Aleltu Hydroelectric Project Summary

■           Ethiopian Electric Light & Power Authority
Aleltu Hydroelectric Project
Reconnaissance and Prefeasibility Studies
Volume 3 - Appendixes June 1984
■
Acres International Limitedj. cA  ,9 Ethiopian Electric Light & Power Authority
r
// >/o-^
Aleltu Hydroelectric Project
Reconnaissance and Prefeasibility Studies
Volume 3 - Appendixes June 1984
nUllfS Acres International LimitedVOLUME 1
VOLUME 2
- EXECUTIVE SUMMARY
-    MAIN REPORT
VOLUME 3         APPENDIXESACKNOWLEDGMENTS ACRES INTERNATIONAL LIMITED
wishes to express its appreciation to the Canadian International Development Agency and the Ethiopian Electric Light and Power Authority for their support in financing and for the many arrangements made in order to carry out this study. We also appreciated the significant contribution and the opportunity to work close with the staff of the Ethiopian Electric Light and Power Authority during this study. Thanks are also due to agencies of the Government of Ethiopia and others who contributed much of the basic information related to the Aleltu Hydroelectric Project.VOLUME 3 - APPENDIXES
TABLE OF CONTENTS
GLOSSARY OF ABBREVIATIONS
LIST OF TABLES
LIST OF PLATES
APPENDIX A - LAYOUT OPTIMIZATION MODEL
APPENDIX B - HYDROLOGICAL STUDIES
APPENDIX C - GEOLOGY, GEOTECHNICAL INVESTIGATIONS AND SEISMICITY
APPENDIX D - SOCIOECONOMIC AND ENVIRONMENTAL ASSESSMENT APPENDIX E - COST ESTIMATE
APPENDIX F - TERMS OF REFERENCEVOLUME 3 - APPENDIXES GLOSSARY OF ABBREVIATIONS
Acres Acres International Limited
ACSR
aluminum core, steel reinforced
ASTM
American Society for Testing and Materials
B/C
benefit/cost
CIDA
Canadian International Development Agency
d
day
DSL
dead storage level
EELPA
Ethiopian Electric Light and Power Authority
ENEL
1
Ente Nazionale Per L Energia Electrica
ERESA
Eritrea Region Electrical Supply Agency
FAO
Food and Agriculture Organization
FI
flood index
FSCL                full surcharge condition level
FSL
ICS
full supply level
interconnected system
MAF
mean annual flood
Mm3
million cubic metres
MM
modified Mercalli
MSL
mean sea level
PF
plant factor
PI
plasticity index
PMF
probable maximum flood
PPS
Power Planning Study
PTD
power tunnel diameterGlossary of Abbreviations - 2
PVC               polyvinyl chloride
r/min               revolutions per minute SCS                self-contained system
t
tonne
UNDP             United Nations Development Program USBR             United States Bureau of ReclamationVOLUME 3 - APPENDIXES LIST OF TABLES
Number            Title
A.l
Results of initial Layout Model Runs
A. 2
Results of Final Layout Model Runs
B.l
Streamflow Records
B.2
Rainfall Records
B.3
Discharge Record Corelations
B.4
Complete and Extended Streamflow Records
B.5
Rainfall Corelations
B.6
Comparison of Chacha and Muger Streamflow Parameters
B.7
Centroid Distances of Subbasins
in Preliminary Hydrology Study
B.8
Monthly Inflow Sequences
of Subbasins
B.9
Reservoir Evaporation Losses
B. 10
Example Jida Reservoir
Regulation Computer Runs
B. 11
Reservoir-Regulation Relationships for Final Model Runs
B. 12
Results of Flood Hydrology Analysis
B. 13                 Flood Index Factors B. 14                 Computed Peak Flows C.l                     Earthquake Intensities
D. 1
Information on Farmer Associations
D. 2                   School LocationsNumber
D.3
D.4
E.l
Title
Health Care Services
Number       and       Percentage       of       Leading Causes for Hospitalization
Prefeasibility Cost EstimateVOLUME 3 - APPENDIXES LIST OF PLATES
Number           Title
A-l
Schematic of Project Components
A-2                  Computer Model Flow Chart
B-l                   Hydrologic Data Base
B-2                  Hydrometric Recording Station
B-3                  Hydrology Studies-DetaiIs
C-l                   Geology of Tiliku Aleltu Dam Site
C-2                  Geology of Jida Dam Site
C-3                  Geological Section of Zega Wedem Gorge C-4                  Geological Stereonets
C-5                  Seismicity of Ethiopia
C-6                   Potential Jima Impervious Borrow Area C-7                   Properties of Impervious Materials
D-l
Environmental DefinitionsAPPENDIX A
TABLE OF CONTENTS
LIST   OF   TABLES
LIST OF PLATES
Page
Al -       MODEL CONCEPT-------------------------------------------------------------------------------- A-       1
A2 -      MODEL COMPUTATIONAL STEPS -----------------------------------------------  A-      2
A3 -      RESERVOIR OPERATION------------------------------------------------------------  A-      2
A3.1 - Individual Reservoir Live Storage ---------------------------------------------  A-      3
A3.2 - Individual Reservoir Degree of
Regulation----------------------------------------------------------------- A- 4
A3.3 - Multireservoir Operation--------------------------------------------------------- A- 5
A4 - SIZING AND COST FUNCTIONS OF PROJECT
COMPONENTS---------------------------------------------------------------------------  A- 6
A4.1 - Dams--------------------------------------------------------------------------------  A- 8
A4.2 - Interconnection Tunnels ---------------------------------------------------------  A- 9
A4.3 - Power Tunnel---------------------------------------- -----------------------------  A-ll
A4.4 - Penstock------------------------------------------------------------------------------    A-14
A4.5 - Powerhouse---------------------------------------------------------------------------- A-16
A4.6 - Other------------------------------------------------------------------------------------ A-17
A5       - ENERGY AND CAPACITY----------------------------------------------------------  A-18
A6       - CALCULATION PROCEDURE-----------------------------------------------------  A-19
A7       - PROGRAM DESCRIPTION-------------------------------------------------------------- A-21
A7.1 -
RESECO-------------------------------------------------------------------------  A-23
A7.2 -
READ-------------------------------------------------------------------------  A-2 3
A7.3 -
MARGIN------------------------------------------------------------------------  A-24
A7.4 -
DEGREG------------------------------------------------------------------------  A-24
A7.5 -
ITER------------------------------------------------------------------------------  A-24
A7.6 -
ROUTE--------------------------------------------------------------------------- A-25
A7.7 -
OPTRES ---------------------------------------------------------------------  A-2 5
A7.8 -
OUTPUT--------------------------------------------------------------------- a-2 5
A7.9 -        Example Output-----------------------------------------------------------------  A-26
PLATESLIST   OF   TABLES LIST OF PLATES
Al - MODEL CONCEPT -------------------------------------
_____________________________  A- 1
A2       - MODEL COMPUTATIONAL STEPS --------------------------------------------------------- A       2
A3       - RESERVOIR OPERATION------------------------------ ~
A_     2
A3.1 - Individual Reservoir
A3.2 - Individual Reservoir Degree of
Live     Storage ----------------------------- a-  j
Regulation-------------------------------------------------------------------------- A“ A3.3 - Multireservoir Operation-------------------------------------------------------------------  A"  5
A4 - SIZING AND COST FUNCTIONS OF PROJECT
COMPONENTS--------------------------------------------------------------------------------  A“ °
A4.1 - Dams-------------------------------------------------------------------------------------  A“ 8
A4.2 - Interconnection Tunnels --------------------------------------------------------------  A- 9
A4.3 - Power Tunnel--------------------------------------------;-------------------------------  A-11
A4.4 - Penstock---------------------------------------------------------------------------------- A-14
A4.5 - Powerhouse------------------------------------------------------------------------------  A-16
A4.6 - Other-------------------------------------------------------------------------------------- A-17
A5 - ENERGY AND CAPACITY---------------------------------------------------------------------  A-18
A6 - CALCULATION PROCEDURE----------------------------------------------------------------- A-19
A7 - PROGRAM DESCRIPTION---------------------------------------------------------------------  A-21
A7.1 
- RESECO--------------------------------------------------------------------------  A
-2 3
A7.2 
- READ---------------------------------------------------------------------------------
-  X-23
A7.3 
- MARGIN-----------------------------------------------------------------------------
-  A-24
A7.4 
- DEGREG-----------------------------------------------------------------------------
-  A-24
A7.5 
— ITER ———— ——— — — — — — — — — — — — — — 
a—94
A7.6 - ROUTE ---------------------------------------------------------------------------------
A7.7 - OPTRES --------------------------------------------------------------------------------
A7.8 - OUTPUT --------------------------------------------------------------------------------
A7.9 - Example Output-------------------------------------------------------------------------
PLATESAPPENDIX A
LIST OF TABLES
Number             Title
A.l                      Results of Initial Layout Model Runs A.2                     Results of Final Layout Model RunsAPPENDIX A LIST OF PLATES Number           Title
A-l
Schematic of Project Components
A-2                  Computer Model Flow ChartAPPENDIX A
LAYOUT OPTIMIZATION MODEL
Al - MODEL CONCEPT
The proposed Aleltu development concept comprises a complex configuration of reservoirs which are interconnected by pressure tunnels and/or open channels. It is assumed that
the project will be developed as one or more independent multireservoir systems; and that each independent system of reservoirs will be connected by a power tunnel and penstock to a powerhouse. This concept is illustrated on Plate A-l.
To handle the complex analysis associated with the inter active operation of the reservoirs and the numerous system alternatives, a mathematical model was developed.
The most significant variable in energy production within a system is reservoir regulation of the inflows. Therefore, 
the objective of the model is to determine reservoir eleva tion and the corresponding dam neight on the basis of one of two criteria
to determine the least cost of the major project structures for a given degree of regulation
to optimize energy production against cost of the major project structures on the basis of marginal cost of long term grid energy supply.A-2
The model is herein referred to as the Layout Optimization Model and a detailed description is contained in the following sections.
A2 - MODEL COMPUTATIONAL STEPS
The principal computational phases of the model consist of
-    operating rules for the multireservoir system
-    sizing and costing of structural components of the system
-    calculation of economic parameters
-    optimizing the dimensions of structural components of the developments
-    calculation of energy production
-    evaluation of economic performance.
The operating rules for the multireservoir system are based on interreservoir sharing in regulating the natural inflows, sharing in supply of power flows and spilling of inflow in excess of the combined storage capability.
A3 - RESERVOIR OPERATION
The purpose of this section is to deserioe in detail tneA-3
characteristics are input functions to the layout optimization model and are outlined in Sections A3.1 and A3.2, respectively. The reservoir operation is described by the reservoir elevation, the regulated flows between inter connected reservoirs, spill, and by the long-term average power flow. This is presented briefly in Section A3.3.
A3.1 - Individual Reservoir
Live Storage
Based on available topographic maps and some field surveys performed during the study, reservoir storage volumes were calculated for a number of reservoir elevations. Regression analyses were then performed to determine the equation des cribing reservoir storage as a function of elevation. The general form of the equation is based on the standard function
y = a + bxc
and was derived to be
A
LS = Ax          + A (EL-EL )
2r
3
(1)
where LS
= reservoir live storage (Mm3)
EL                       = reservoir FSL (m)
ELr
9 
= reference (dead storage) elevation 9        ^3 “ site-specific coefficients related
storage
(m) to liveA-4
A3.2 - Individual Reservoir
Degree of Regulation
To evaluate potential Aleltu developments  it was necessary 
r
to assume that benefits are derived from firm (primary) energy generation only. Secondary energy is assumed to have negligible economic value.* Firm energy corresponds directly with the firm power flow from the reservoir. By defining the firm power flow of an individual reservoir and subsequently that of the entire multireservoir system, the energy benefit
is implicitly described.
The firm power flow corresponds to the reservoir discharge that can be sustained throughout the periods of dry hydro logy. Degree of regulation is defined as the firm power flow divided by the long-term average flow. (Thus, the degree of regulation can vary from 0.0 to 1.0. For example, a reser voir which fully regulates the inflow has a degree of regula tion equal to a value of 1.0.) By using a mass curve analy sis, the firm power flow was determined for a specific reser voir elevation. A description and example of the mass curve analysis is presented in Appendix B. By repeating tne mass curve analysis for several reservoir elevations, the reser voir degree of regulation was defined as a function of reser voir live storage by the same standard function as for the live storage (Section A3.1 aoove) and resulted in the following equation.
•This assumption is based on the fact that the interconnected system (ICS) is an all-nydro system. However, complementary operation of the existing I<_S reservoirs can permit firming up of about 200 GW-h/yr of secondary energy. This is not considered in the model, as discussed in Section 7 of the
main report.A-5
DOR X Q ma where
+ B (LS)
2
(2)
DOR
= degree of regulation
Qma
= mean annual flow
Qp
LS
= firm power flow
= live storage
B l' B2'
= site-specific coefficients related to power
flow
A3.3 - Multireservoir Operation
The reservoir live storage (Section A3.1) and the reservoir degree of regulation (Section A3.2) describe the hydraulic capabilities of individual river/reservoir complexes. The operation of the multireservoir system is based on the
following specific characteristics of the Aleltu develop
ment .
(a) The reservoirs are interconnected by pressure tunnels or open channels. Excess water in one reservoir is distri buted to other reservoirs, as storage is available, to minimize spill.
(b)       Natural inflows are routed through the reservoirs in one of three ways
- regulated by the reservoir(s) constructed in the
specific river
- discharged through interconnection tunnels or channels to De regulated by other reservoirs in the multireservoir systemA-6
- spilled from the multireservoir system.
The system operation is determined by a water balance of the natural inflows, regulated discharges and spill tnroughout the network. The long-term average power flow is equivalent to the regulated flow which can be supplied by a specific multireservoir system.
A4 - SIZING AND COST FUNCTIONS
OF PROJECT COMPONENTS
The system components (Plate A-l) which have a significant influence on project cost are
-    dams
-    interconnecting tunnels
-    power tunnel
-    penstock
-    powerhouse.
The sizing and costing functions of these components were defined in terms of reservoir operation as follows.
Component Dams
Size and Cost Function Reservoir full supply level (FSL)
Interconnecting
Tunnels
Regulated discharge (long-term average
power flow) and unregulated discharges
(expressed as a linear function of
long-term average power flow)A-7
Component Power Tunnel Penstock Powerhouse
Size and Cost Function
Long-term average power flow
Long-term average power flow
Reservoir mean operating level (defined by the FSL) and long-term average power flow
It can be seen that the cost functions of the individual components contain two variables
-    the reservoir FSL
-    the long-term average power flow.
These variables are interdependent: to each FSL belongs a long-term average power flow equal to or less than the mean annual inflow.
Therefore, for any given FSL, all project costs are defined, and marginal costs can be calculated. The optimum FSL can be determined by calculating the marginal costs and correspond ing marginal benefits for a number of reservoir levels.
The cost functions are discussed in the following sections. It is noted that the costs of additional components such as the surge chamDer, spillways, access, etc, are included as part of the costs of the individual components, as applic able.A-b
A4.1 - Dams
The cost function of the dams in the Aleltu development is related to dam volume. The dam volume is dependent on reser voir elevation and topography of a specific site. Based on a standard layout for earth- and rock-fill dams, volumes for dams were determined for various reservoir elevations. The standard layout was based on dam slopes of 2.5H:1V for dam heights less than 25 m, and 3H:1V for dam heights in excess of 25 m.
Therefore, for each reservoir site, dam volumes were calcu lated in terms of reservoir elevation and were defined by the following equation.
C (EL-EL )
2r
where
DV                       = dam volume (Mm3)
(3)
EL ELr
C 1' C2'
= reservoir FSL (m)
= reference (dead storage) elevation (m) C  = site-specific coefficients
3
Unit costs of dam fill material were assumed to vary with the quantity of fill material and were defined on the basis of
the following equation.
UCD
D2(DV)
(4)A-9
where
DV                     = dam volume (Mm3)
UCD                   = unit cost of dam volume ($ mi 11ion/Mm3) D , D , D  = cost coefficients
23
The resulting dam cost function
DC = UCD x DV
where
DC = dam cost ($ million)
DV = dam volume (Mm3)
UCD = unit cost of dam volume ($ million/Mm3) A4.2 - Interconnection Tunnels
is then defined as follows.
(5)
The principal design feature of the interconnection tunnels is the diameter. The selection of a design diameter is dependent on the regulated and unregulated flows to be discharged through the tunnel. The design criteria for tne tunnel diameter are as follows.
(a) Regulated Discharges
To limit the extent of water level fluctuation within the reservoir system, a maximum head loss over the tunnel length of 1.0 m was arbitrarily selected. The discharge used in the calculation is equivalent to the regulated discharge.A-10
(b) Unregulated Discharges
To permit distribution of unregulated inflows over the reservoirs, particularly during peak runoff, a discharge of six times the regulated discharge at a head loss of 5.0 m was allowed.
The design diameter of the interconnection tunnel was derived through the use of the Darcy-WeisDach equation
HL =
where
(6)
HL = head loss
f = friction factor
L = tunnel length
D = tunnel diameter
v = tunnel flow velocity
g = acceleration of gravity
This resulted in the following equation. ITD = E  X (Q ) ’  x (ITL) *2
04                   0 xp
where
(7)
°p ITL =
= regulated (power) discharge = tunnel length
El =    = constant, comprising friction factor, design, discharge multiplier, etcA-ll
The         interconnection         tunnels         are         assumed         to         be         unlined.         Their cost function is defined as follows (0.5-m overbreak
excavation is allowed for).
2
ITC = E  x [E  + E (ITD) ] ITL
234
where
(8)
ITC
= interconnection 
tunnel
cost ($ million)
ITD
= interconnection 
tunnel
diameter (m)
ITL
= interconnection 
tunnel
length (m)
E2               = unit cost of excavation for interconnection tunnel (is constant) ($/m3)
E , E  = specific coefficients
34
A4.3 - Power Tunnel
To establish the variation of tunnel cost with power flow, the definition of optimum tunnel diameter is required. Opti mization of the power tunnel diameter is carried out on the basis of marginal variation in the cost of construction and value of head loss, such that the marginal cost is equal to the marginal benefit.
The marginal benefit is derived from energy savings due to head loss reduction in the power tunnel with respect to increased tunnel diameter. The marginal benefit is evaluated using the long-term average grid cost of energy.
Costs are based on a concrete-lined tunnel. The marginal annual cost of the power tunnel is derived by differentiating the annual cost function of the power tunnel with respect toA-10
(b) Unregulated Discharges
To permit distribution of unregulated inflows over the
reservoirs, particularly during peak runoff, a discharge
of six times the regulated discharge at a head loss of
5.0 m was allowed.
The       design       diameter       of       the       interconnection       tunnel       was       derived through the use of the Darcy-Weisbach equation
(6)
wnere
HL = head loss
f = friction factor
L = tunnel length
D = tunnel diameter
v = tunnel flow velocity g = acceleration of gravity This resulted in the
following equation.
(7)
where
= regulated (power) discharge
ITL = tunnel length
= constant, comprising friction factor, design, discharge multiplier, etcA-ll
The         interconnection         tunnels         are         assumed         to         be         unlined.         Their cost function is defined as follows (0.5-m overbreak
excavation is allowed for).
2
[E  + e (itd) ] itl
34
(8)
where
ITC
= interconnection 
tunnel
cost ($ million)
ITD
= interconnection 
tunnel
diameter (m)
ITL
= interconnection 
tunnel
length (m)
E 2                       = unit cost of excavation for interconnection tunnel (is constant) (S/m^)
E^, E  = specific coefficients
4
A4.3 - Power Tunnel
To establish the variation of tunnel cost with power flow, the definition of optimum tunnel diameter is required. Opti mization of the power tunnel diameter is carried out on the basis of marginal variation in the cost of construction and value of head loss, such that the marginal cost is equal to the marginal benefit.
The marginal Denefit is derived from energy savings due to head loss reduction in the power tunnel with respect to increased tunnel diameter. The marginal benefit is evaluated using the long-term average grid cost of energy.
Costs are based on a concrete-lined tunnel. The marginal annual cost of the power tunnel is derived by differentiating the annual cost function of the power tunnel with respect toA-12
the diameter. The tunnel cost function contains an excava tion component and a concrete liner component. Costs for access and mucXing are incorporated in the unit cost of excavation. On this basis, the power tunnel cost per unit of length is as follows.
C  + ir(PTD + tp t  C J x PTL
1
}2
x PTD2        x PTL
where
PTC = power tunnel unit cost ($ million/km)
PTD          = power tunnel diameter (m)
(9)
PTL
= power tunnel length (km)
C1
UCPTi
= concrete liner thickness equals PTD/15 (m)
= unit cost of tunnel excavation (constant)
ucpt2
= unit cost of concrete (constant)
?1
= constant
The tunnel cost was amortized over a 50-yr period at a discount rate of 12% to determine equivalent annual costs.
The unit energy benefit as a function of head loss in the
power tunnel is evaluated utilizing tne Darcy-Weisbacn formu lation of head loss (see Section A4.2 above), resulting in 
the following equation.
PTB
x W x PTL
( 10)A-13
where
PTB
= unit power tunnel energy benefit ($ million/kra)
fQ
Qp 
W
= weighted flow factor
= long-term average power flow (m^/s)
= grid cost of energy (mills/kW*h)
PTL
= power tunnel length (km)
f2
= constant
The weighted flow factor (fg) is used to adjust the power flow to represent plant stacking conditions in the ICS load duration curve (i.e., to reflect the peaking role). For this purpose, a weighted mean power flow is calculated as follows.
Q           = weighted mean                power flow
T, t =        duration
Qp         = mean power flow
fq            = flow factor
Various plant operation  modes were used  to  determine probable stacking  configurations and  the corresponding  flow factor was calculated. Ultimately, a factor of 1.30 was adopted.
The economic diameter was calculated by equating the marginal cost and marginal benefit functions, and solving the power tunnel diameter (PTD).A-14
3PTC  3PTB
3PTD ’ 3PTD
(12)
The       optimum       power       tunnel       diameter       for       the       layout       optimization model was found to De
PTD = F3
3/7
(13)
and the power tunnel cost for fg equals 1.30 is
6/7
PTC = F  x (Q ) x PTL
4p
where
PTD          = power tunnel diameter (m)
PTC          = power tunnel cost (S million)
PTL           = power tunnel length (km)
°P              = mean power flow (m /s)
F 4 = constants
A4.4 - Penstock
Penstock diameters are optimized on the same oasis of
installed        cost        and        value        of        head        losass for tfheor  power tunnel.
Because of Che high head, the penstock cost function is
(14)
3
developed by considering the desian of ments. Each segment is defined in terms of
.       . . 
’ tne Penstock in seg rms of ^e length of
,
penstock within a particular elevaH«„            elevation ran9e and, therefore
the penstock diameter is assumed to be cone
segment.  Segments were evaluated  for r eacfl
(
. 
therefore, constant for each
u       . 
 100 m of eleva
tion. The following equations illustrar k
a cost function for each penstock segment " 6 deVel°pment °fThe        thickness        of        steel        plate hydrostatic head.
A-15
in the penstock increases with
( 15)
where
t2 = thickness of steel plate in penstock (m)
H| = hydrostatic head (m) for penstock segment "i"
PD = penstock diameter (m)
F = allowable tensile stress (2,426 kg/cm2)
The unit weight of the penstock is given as follows.
U = yll( PD + t )
2                        1,000
where
U = unit weight                 of penstock (kg/m)
y = density of                 steel (7,850 kg/m3)
The unit cost of penstock construction is given as follows. p   — c°s u
P       1,000 where
(16)
(17)
Cp = unit cost
Cg = unit cost
of    penstock (§ million/km) of     steel construction (52.50/kg)A-16
An     average     cost     coefficient     was     determined     on     the     basis     of all penstock segments.
Similar     to     the     power     tunnel,     the     unit     energy     benefit     due     to energy savings is evaluated from the Darcy-Weisbach formula.
(18)
The marginal cost and benefit is computed by differentiating the appropriate function with respect to the penstock dia meter. By equating the two marginal costs and solving for penstock diameter, the economic diameter is given as follows.
PD = G  x
2
(19)
and the penstock cost is
x (Q )
p
6/7
x PL
(20)
where
PD
= penstock
diameter (m)
PC
= penstocx
cost ($ million)
PL
= penstocx
length (km)
On             = mean power flow (m^/s)
G 2' G3 = conscants 9iven particular lengtn versus depth profile of penstock
A 4.5 - powerhouse
The cost of the powerhouse is equal to the summation of equipment cost and structural powerhouse cost, includingA-17
switchyard, and was expressed as the unit cost of installed capacity. This was estimated at $250/kW. The formulation of installed capacity is as follows.
IC = H
net
where
x Q x H P
(21)
IC       = installed capacity
H        = net head
net
Qp = power flow
= coefficient, incorporating plant factor (see Section A5) efficiency, etc
Since the net operating head can be calculated from the hydraulic losses in the conveyance system (see Section A5), the powerhouse cost function becomes as follows.
PHC   =   [H_ 
2 
x   Q
p
]
x W + H3
( 22)
where
PHC = powerhouse cost ($ million)
Qp = long-term average power flow
H2         =         coefficient         related         to         capacity         function         (Hnet
and )
H3 = lump sum costs from separate project components (see
Section A4.6)
W = unit cost of installed capacity
A4.6 - Other
Lump       sum       costs       were       calculated       for       separate       components       of       tne project, such as access, surge chamber and transmission.
These       costs       were       introduced       in       the       model       as       independent       costs and were accommodated under powerhouse cost.A-16
An      average      cost      coefficient      was      determined      on      the      basis      of all penstock segments.
Similar       to       the       power      tunnel,      the energy savings is evaluated from
unit      energy      benefit      due      to the Darcy-Weisbach formula.
PEB = GJ
3
x W
(18)
The marginal cost and benefit is computed by differentiating the appropriate function with respect to the penstock dia meter. By equating the two marginal costs and solving for penstock diameter, the economic diameter is given as follows.
(19)
and the penstock cost is 6/7
X (Q )
p
x PL
( 20)
where
PD             = penstock diameter (m) PC             = penstock cost ($ million) PL             = penstock length (km)
Qp
G , g  =
23
= mean power flow (m-^/s)
= constants given particular length versus depth profile of penstock
4.5 - powerhouse
The cost of tne powerhouse is equal to the summation of equipment cost and structural powernouse cost includingA-17
switchyard, and was expressed as the unit cost of installed capacity. This was estimated at $250/kW. The formulation of installed capacity is as follows.
(21)
where
IC      =  installed capacity H       =  net head
net
Qp  = power flow Hjl = coefficient, 
incorporating plant factor (see
Section A5) efficiency, etc
Since the net operating head can be calculated from the hydraulic losses in the conveyance system (see Section A5) , the powerhouse cost function becomes as follows.
PHC = (H x QI 2 P
X W + h3                                                                                                                                   (22)
where
PHC = powerhouse cost ($ million)
Qp = long-term average power flow
H2 = coefficient related to capacity function (Hnet
and Hp
H3 = lump sum costs from separate project components (see
Section A4.6)
W = unit cost of installed capacity
A4.6 - Other
Lump       sum       costs       were       calculated       for       separate       components       of       tne project, sucn as access, surge chamber and transmission.
These       costs       were       introduced       in       the       model       as       independent       costs and were accommodated under powerhouse cost.A-18
A5 - ENERGY AND CAPACITY
The       generation       capability       of       the       project       is       derived       from       the general relationships as follows.
Capacity (CAP) = 9.812 n x Qpk x Hngt
Energy (E) where
p          net x time = 9.812 n x Q  x H
(23)
(24)
n = overall turbine/generator efficiency (0.85)
Qpk = Peak flow equals Ql/PF
Qp = regulated (power) flow
Hnet = net head (m)
From consideration of the ICS characteristics in the 1990s, a plant factor (PF) of about 0.4 was adopted (see Section 7 of the main report).
The net head is the difference between average operating reservoir level and the centerline of the power nozzles on the turbines (ELEV?) in the powernouse, less losses, i.e., as follows.
H = DSL + 0.75 (FSL - DSL) - ELEV - H - H
net
where
DSL = dead storage level (m) FSL = full supply level (m)
r
i LT LP
(25)
Hlt  = head loss in power tunnel (m)
h LP = head loss in PenscocK
The term "0.75 (FSL - DSL)" provides a weighted average operating level of the reservoir.A-19
A6 - CALCULATION PROCEDURE
With  the formulas presented  in  Sections A3  to  A5,  the average and  incremental cost of energy  can  be calculated  for selected reservoir FSL. Optimum component sizing is carried out
simultaneously.
For a given  FSL,  the marginal cost of the project corresponds to  the sum of the incremental costs of the individual project components and is determined in the following manner.
From        the        individual        reservoir        live        storage,        the        change        in power flow amounts to
3Q _ 3Q BLS
3EL BLS X 3EL
The incremental costs are as follows. Dam
3 DC  3 DC 3DV BEL " 8DV X 3EL Interconnection Tunnel
(26)
( 27)
3ITC
BEL          3ITD X Power Tunnel
3ITC          3ITP 3Q 3LS
in
8Q BLS 3 EL
A
n r o x
( 28)
3PTC 3EL
3PTC
9Q     x
3Q8LS_ B 3ELLS
r              A » r-< V
( 29)A-20
Penstock
3PC  3PC 3Q 3LS
3EL 3Q X 3LS X 3ELC Powerhouse
( 30)
3PHC
=
3PHC      3Q      3LS
3EL              3Q X 3LS X 3EL The incremental project cost 3Project Cost  3DC 3ITC
(31)
3EL
3EL + 3EL
is then
3PTC 3PC 3PHC 3EL * 3EL * 3EL
( 32)
where
Q        = power flow (m^/s)
EL     = FSL (m)
LS      = live storage (Mm3)
DC     = dam cost ($ million)
DV =  = dam volume (Mm3)
ITC = = interconnection tunnel cost (S million)
ITD = = interconnection tunnel diameter (m)
PTC = = power tunnel cost ($ million)
PC =   = penstock cost ($ million)
PHC = = powerhouse cost ($ million)
The     margina     1     unit     costs     of     available     firm     energy     can     now     be calculated.
MUC      A x
3Project Cost  3E
3EL                ’ 3EL
f
( 33)A-21
where
MUC = marginal unit cost (mills/kW«h)
A       =       amortization       factor       at       12%       over       50       years
E = available firm energy (GW-h/yr)
and        this        is        compared        to        the        long-term        incremental        supply        cost of 35 mills/kW«h.
The        average        unit        cost        of        available        energy        is        calculated        as follows.
AUC = Project Cost * E where
( 34)
AUC
= average unit cost (mills/kW*h)
Project Cost = DC+ITC+PTC+PC-t-PHC ($ million)
A7 - PROGRAM DESCRIPTION
The following model logic was developed for evaluation of total project cost estimates for a chosen project
conf iguration.
( 1)       Select an elevation design
(2)       From the given dam neight, evaluate (a)        the total dam volume
height for the dam.
(b)        tne live storage availade to regulate inflows.A-22
(3)       From the total dam volumes, estimate dam costs.
(4)       From the live storage available, evaluate the degree or
river regulation.
(5)       From the degree of river regulation, evaluate long-term
average regulated outflows from each reservoir.
(6)      From the long-term average inflow and the regulated 
long-term average outflow of each reserovir, evaluate
(a)       tne regulated diversion flow between reservoirs
(b)       the unregulated diversion flow between reservoirs
(c)       the regulated power flow from tne head pond
reservoir.
(7)         From the regulated and unregulated diversion flow of
each diversion tunnel, determine the economic diameter
of each diversion tunnel.
(8)       From the economic diameter of the diversion tunnel, 
determine tne diversion tunnel costs.
(9)       From      the      regulated      power      flow,   determine       the economic diameter of the
(a)       power tunnel
(b)       penstock.
From the economic diameter and the length of the powe tunnel, determine the power tunnel costs.
(11)        From the economic
diameter and tne length
of    tne
penstock, determine the penstock costs.A-23
(12)        From     the   economic
sizing        of    the     power tunnel, determine
the
head
loss.
(13)        From     the   economic       sizing        of    the     penstock, determine the
head        loss •
(14)                From the elevation design height of the head pond and 
tne head loss in the power tunnel and penstock, deter
mine the design head of the powerhouse.
(15)        From the regulated power flow and design head,
determine        the        long-term        energy        production        of        the        confi guration.
(16)        From the (given) plant factor, the regulated power flow and the design head, determine the installed capacity of the powerhouse.
(17)        From the installed capacity, determine the powerhouse cost.
(18)        Sum the component costs to determine the total project cost estimate.
Steps 1 to 18 are repeated for a small increment in design height to evaluate the marginal cost of energy production for the given project at that design height. The design height
of the project is adjusted and the marginal cost of project energy is reevaluated at the new design height. The design height continues to be adjusted until the marginal cost of energy production for the project configuration is equal to the marginal cost of grid energy in the Ethiopian power system.A-2 4
The logic layout optimization model is developed in a series of computer program subroutines or modules. A description of these modules is given in the following subsections. The flow chart (Plate A-2) shows the interaction between these
modules.
A7.1 - RESECO
The main module is termed RESECO (acronym for reservoir economics). RESECO contains the overall logic of the model and systematically calls other modules to analyze a specific multireservoir system.
A7.2 - READ
Basic project data are extended into the program by subroutine READ.
A 7.3 - MARGIN
Subroutine MARGIN determines
(a) tne opL.fnum dimensions and costs of the following major project components
-   dams
-   diversion tunnels
-   penstocks
-   power tunnels
-    installed capacities
(b) total project costs.A-25
A7.4 - DEGREG
Parameters determined in subroutine DEGREG relate to the capability of the reservoirs, including
-   live storage available at each reservoir
-   degree of regulation available at each reservoir
-   total live storage available in the system
-   available system degree of regulation.
A7.5 - ITER
Subroutine ITER determines the total live storage required in 
the system to achieve a given system degree of regulation. 
The system live storage is calculated through an interactive
process.
A7.6 - ROUTE
Subroutine ROUTE calculates
(a) the regulated and unregulated flows required to be passed by the interconnection tunnels between
reservoirs
(b) the power flow.
A7.7 - OPTRES
Subroutine OPTRES calculates the optimum reservoir elevation such that one of the following conditions holds.A-24
The logic layout optimization model is developed in a series of computer program subroutines or modules. A description of these modules is given in the following subsections. The flow chart (Plate A-2) shows the interaction between these
modules.
A7.1 - RESECO
The main module is termed RESECO (acronym for reservoir economics). RESECO contains the overall logic of the model and systematically calls other modules to analyze a specific multireservoir system.
A7.2 - READ
Basic project data are extended into the program by subroutine READ.
A7.3 - MARGIN
Subroutine MARGIN determines
(a) the optimum dimensions and costs of the following major project components
-   dams
-   diversion tunnels
-   penstocks
-   power tunnels
-    installed capacities
(b) total project costs.A-25
A7.4 - DEGREG
Parameters determined in subroutine DEGREG relate to the capability of the reservoirs, including
-   live storage available at each reservoir
-   degree of regulation available at each reservoir
-   total live storage available in the system
-   available system degree of regulation.
A7.5 - ITER
Subroutine ITER determines the total live storage required in 
the system to achieve a given system degree of regulation. 
The system live storage is calculated through an interactive
process.
A7.6 - ROUTE
Subroutine ROUTE calculates
(a) the regulated and unregulated flows required to be passed by the interconnection tunnels between
reservoirs
(b) the power flow.
A7.7 - OPTRES
Subroutine OPTRES calculates
the optimum reservoir elevation
such that one of the following conditions holds.A-2 6
- The marginal cost of energy equals the average grid cost of energy.
- The reservoir inflows are completely regulated.
A7.8 - OUTPUT
Subroutine OUTPUT prints a detailed summary of
-   project components for each selected reservoir design elevation
-   tne analysis for the selected and optimum reservoir design elevations.A 7.9 - Example Output
ACRES CONSULTING SERVICES LTD ALELTU PRE-tEASIBILITY STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OE PROJECT SIZING TILIKU • JIDA : PEN TIL TO A
RESERVO II STRUCTURE
NODE RES NAME
3            TILIKU
4               JIDA
GENERAL INPUT DATA
DUN NODE UP NODES
0
3
RESERVOIR ELEVATION (M) =                 2610.00 2605.00 2600.00 2595.00 2590.00 2525.00 2580.00A-28
ACRES CONSULTING SEW ICES LTD ALELTU PRE-FEASIBILITY STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OF PROJECT SIZING TRIXU - JIDA : PEN TIL TO A
RESERVOIR DATA
NODE
RES NAME
DISCH REG
DSEL
NIN LS
HAX LS
U/S LS
U/S LS CST
1
n
AGAT
1.2600
2560.0000
35.3000
84.4600
0.0000
0.0000
TINISHU
0.4700
2560.0000
9.1000
20.3900
0.0000
6.0000
3
TILIKU
5.5700
2560.0000
202.9000
401.1800
0.0000
4.0000
4
JIDA
3.1600
2560.0000
238.2000
707.1200
0.0000
1.3000
5
COMORO
2.4100
2577.0000
49.3000
196.9600
0.0000
0.0000
6
ROB I
4.2900
2588.0000
97.1000
279.2700
0.0000
0.0000
COEFFICIENTS LIVE STORAGE VS ELEVATION
NODE
1
RES NAME
AGAT
Al
0.8400000
A2
1.6020000
*>
to
TINISHU
0.0000000
0.0000000
3 TILIKU
4            JIDA
5 GOMORO
6            ROB I
0.0008890                 3.1501000
0.1281750                 2.4626000
0.0540500                 2.8209000
0.3660800 2.4782000
COEFFICIENTS PERCENT REGULATION VS LIVE STORAGE
NODE             RES NAME
Al
A2
A3
A4
1
2
AGAT
TINISHU
0.2355000
0.1800000
0.0131600
0.0571000
0.0019100
0.0133600
1.3356000
1.3406000
3
4
TILIKU
JIDA
0.4025500
0.1707000
0.0019589
0.0022220
0.0006653
0.0011288
1.0674000
1.0549000
5
6
COMORO
ROB I
0.2477000
0.2894300
0.0091743
0.0042283
0.0027103
0.0003949
1.1940000
1.3607000
COEFFICIENTS DAM VOLUME VS ELEVATION
NODE
RES NAME
1
2
AGAT
TINISHU
Al
1.2230000
A2
0.0420000
A3
1.4250000
3
TILIKU
0.0000000
0.0070000
0.0000000
0.0002243
0.0000000
2.3076000
4
JIDA
5
6
GOMORO
0.2370000
0.0000000
0.0086340
0.0003063
1.3575000
2.7452000
ROB I
0.0000000
0.0011862
2.2892000A-29
ACRES CONSULTING SERVICES LTD                          ALELTU PRE-FEASIBILITY STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OF PROJECT SIZING
TILDCU - JIDA : PEN TIL TO A
RESERVOIR CONNECTIVITY
RESERVOIR CONNECTION                      LENGTH                      NODAL CONNECTIONS
AGAT   -   TINISHU
7.40
1
2
TINISHU     -     TILIKU
4.40
2
3
TILDCU    -    JIDA
2.11
3
4
JIDA  -  COMORO
7.30
4
5
COMORO - WENZ
6.00
5
6
AGAT    -    TILIKU
14.10
1
3
AGAT - JIDA
16.60
1
4
GENERAL COEFFICIENTS
DAM COST
COEFFICIENT
(1)  =
IS.0000
DAM COST
COEFFICIENT
(2)  =
4.0000
DAM COST
COEFFICIENT
(3)  =
0.3000
ENERGY COST =
35.00 (MILS/KWH)
PLANT FACTOR =
0.4000
FLOW FACTOR -
1.4000
COEFF FOR POWER TUNNEL DIAM (TILIKU - A) = 0.362330
COEFF FOR POWER TUNNEL COST (TILIKU - A) = 0.163340
POWER TUNNEL LENGIH (TILIKU - A) = FRICTION FACTOR FOR POWER TUNNEL (TILIKU - A) =
15.51 (KM)
0.018000
COEFF FOR PENSTOCK DIAMETER (PENSTOCK A) =                    0.751450 COEFF FOR PENSTOCK COST (PENSTOCK A) =                   1.578660
PENSTOCK LENGTH (PENSTOCK A) =
3.13 (KM)
FRICTION FACTOR FOR PENSTOCK (PENSTOCX A) =                      0.012000 BASE HEAD FOR POWERHOUSE .PENSTOCK A) =                    1030.00 (M)
COEFFICIENT FOR CAPACITY COST (PENSTOCK A) =
250.00 (»/KU)
BASE POWERHOUSE COSTS ( ACCESS * TRANSMISSION ) (PENSTOCK A) =
22.12 ( M»A-28
ACRES CONSULTING SERVICES LTD ALELTU PRE-FEASIBILITT STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OF PROJECT SIZING TILIKU - JIDA : PEN TIL TO A
RESERVOIR DATA
NODE
RES NAME
DISCH REG
DSEL
MIN LS
MAX LS
U/S LS U/S LS CST
1
n
AGAT
1.2600
2560.0000
35.3000
84.4600
0.0000
0.0000
TINISHU
0.4700
2560.0000
9.1000
20.3900
0.0000
6.0000
3
TILIKU
5.5700
2560.0000
202.9000
401.1800
0.0000
4.0000
4
J IDA
8.1600
2560.0000
238.2000
707.1200
0.0000
1.3000
5
GOMORO
2.4100
2577.0000
49.3000
196.9600
0.0000
0.0000
6
ROB I
4.2900
2588.0000
97.1000
279.2700
0.0000
0.0000
COEFFICIENTS LIVE STORAGE VS ELEVATION
NODE
RES NAME
Al
A2
1
AGAT
0.8400000
1.6020000
2
TINISHU
0.0000000
0.0000000
3
TILIKU
0.0008890
3.1501000
4
JIDA
0.1281750
2.4626000
5
GOMORO
0.0540500
2.8209000
6
ROB I
0.3660800
2.4782000
COEFFICIENTS PERCENT REGULATION VS LIVE STORAGE
NODE
RES NAME
Al
A2
1
AGAT
0.2355000
0.0131600
2
TINISHU
0.1800000
0.0571000
A3
0.0019100
0.0133600
3
TILIKU
0.4025500
0.0019589
4
JIDA
0.1707000
0.0022220
0.0006653
0.0011288
A4
1.3356000 1.3406000 1.0674000 1.0549000
5
GOMORO
0.2477000
0.0091743
0,0027103
6
ROB I
0.2894300
0.0042283
0.0003949
1.1940000
1.3607000
COEFFICIENTS DAM
VOLUME VS ELEVATION
NODE
RES NAME
Al
A2
1
AGAT
1.2230000
0.0420000
2
TINISHU
0.0000000
0.0000000
3
TILIKU
0.0070000
0.0002243
A3
1.4250000
0.0000000
2.3076000
4
JIDA
0.2370000
0.0086340
1.3575000
jr
GOMORO
0.0000000
0.0003063
2.7452000
6
ROB I
0.0000000
0.0011862
2.2892000A-29
ACRES COMSULTING SERVICES LTD ALELTU PRE-FEASIBILITY STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OF PROJECT SIZING TILIXU - JIDA : PEN TIL TO A
RESERVOIR CONNECTIVITY
RESERVOIR CONNECTION
LENGTH
NODAL CONNECTIONS
AGAT - TINISHU
7.40
1
2
TINISHU - TILIKU
4.40
2
3
TILIKU - JIDA
2.11
3
4
JIDA - GOMORO
7.80
4
5
COMORO - WENZ
6.00
5
6
AGAT - TILIKU
14.10
1
3
AGAT - JIDA
16.60
1
4
GENERAL COEFFICIENTS
DAN      COST      COEFFICIENT      (1)      =      15.0000
DAN      COST      COEFFICIENT      (2)      =      4.0000
DAN COST COEFFICIENT (3) = 0.3000
ENERGY COST =                35.00 (NILS/KWH)
PLANT FACTOR »               0.4000
FLOW FACTOR =              1.4000
COEFF    FOR    POWER    TUNNEL    DIAN    (TILIKU    -    A)    =    0.362330
COEFF FOR POWER TUNNEL COST (TILIKU - A) = 0.163940
POWER TUNNEL LENGTH (TILIKU - A) = FRICTION FACTOR FOR POWER TUNNEL (TILIKU - A) =
15.51 (KM)
0.018000
COEFF FOR PENSTOCK DIAMETER (PENSTOCK A) =                    0.751450 COEFF FOR PENSTOCK COST (PENSTOCK A) =                   1.578660
PENSTOCK LENGTH (PENSTOCK A) =
3.13 (KN)
FRICTION    FACTOR    FOR    PENSTOCK    (PENSTOCK    A)    =    0.012000 BASE HEAD FOR POWERHOUSE (PENSTOCK A) =                    1030.00 (M)
COEFFICIENT FOR CAPACITY COST (PENSTOCK A) =
250.00 iS/KW)
BASE POWERHOUSE COSTS ( ACCESS ♦ TRANSMISSION ) (PENSTOCK A) =
22.12 ( M$ACRES CONSULTING SERVICES LTD
A-30
ALELTU PtE-FEASIBILITY STUD!
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OF PROJECT SIZING
TILIKU - JIDA : PEN TIL TO A
RESULTS FOR ELEVATION 2610.00 (M)
RESERVOIR
NUMBER
DAN
VOLUME
DAM LIVE DEGREE TUNNEL
COST STORAGE REGULATION COST
TUNNEL
DIAMETER
UNREG
FLOW
REG
FLOW
3                  1.8746             23.0654           199.9111             0.7942              0.0000              0.0000             0.0000           13.7300 4               12.5979               82.5108         1957.4328             1.0000              2.2325              4.0253            -1.1466              9.3066
SYS               14.4725             105.5762         2157.3439             1.0000              2.2325
PENSTOCK DESIGN
DIAM (M.;=
2.3575 HEAD
LOSS (M.)=
22.0114
COST (Ml)=
POUER TUNNEL DESIGN
DiAM (M.) =
3.1992 HEAD
LOSS (M.)=
35.5980
COST (Ml) =
15.5237
26.0242
RESULTS FOR ELEVATION 2605.00 (M)
RESERVOIR DAM
NUMBER VOLUME
DAM LIVE DEGREE TUNNEL
COST STORAGE REGULATION COST
TUNNEL
DIAMETER
UNREG            REG
FLOW FLOW
3
4
1.4716
10.4008
19.4638
73.3181
143.4486
1510.0957
0.6836
1.0000
0.0000
2.3455
0.0000
4.1298
0.0000
-1.7626
13.7300
9.9226
SYS              11.8723               92.7819       1653.5443               1.0000              2.3455
PENSTOCK DESIGN
POWER TUNNEL DESIGN
DIAN (M.)=
DIAM (M.)=
2.3575 HEAO LOSS (M.)= 22.0114 COST (Ml)= 15.5237
3.1992 HEAD LOSS iM.)= 35.5980 COST (Ml)= 26.0242
RESULTS FOR ELEVATION 2600.00 (M)
RESERVOIR
NUMBER
DAM
VOLUME
DAM
COST
LIVE DEGREE
STORAGE REGULATION
TUNNEL
COST
TUNNEL UNREG
DIAMETER FLOW
REG
FLOW
3
4
1.1230
3.4035
16.1940
63.6940
98.9830
1129.8902
0.5964
1.0000
0.0000
2.4336
0.0000
4.2094
0.0000
-2.2478
13.7300
10.4078
SYS                9.5266                79.3879     1223.9733                 1.0000              2.4336
PENSTOCK DESIGN
POWER TUNNEL DESIGN
DIAM (M.)= 2.3575
DIAM (M.) = 3.1992
HEAD LOSS (M.)= 22.0114
HEAD LOSS (M.)= 35.5980
COST (Ml)= 15.5237
COST (Mi) = 26.0242A-31
ACRES CONSULTING SERVICES LTD                           ALELTU PRE-FEASIBILITY STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OE PROJECT SIZING
TILIXU - JIDA : PEN TIL TO A
RESULTS FOB ELEVATION 2595.00 (M)
RESERVOIR
NUMBER
DAM
VOLUME
DAM                   LIVE DEGREE
TUNNEL          TUNNEL                 UNREG                  REG
COST
STORAGE
REGULATION
COST
DIAMETER
FLOW
aow
3
4
0.8271
6.60%
13.2808
53.3547
64.9950
0.5299
0.0000
2.2957
0.0000
4.0840
0.0000
12.6011
8
13.2523
1.0000
-2.1607
9.6498
SYS                7.4367             67.1355         878.2473                 0.9178
2.2957
PENSTOCK DESIGN            DIAM
POWER TUNNa DESIGN DIAM
(M.)=        2.2724        HEAD        LOSS        (M.)= (M.)= 3.0837 HEAD LOSS (M.)=
22.2832
36.0375
COST (M$)= 14.4231
COST (M»)= 24.1789
RESERVOIR DAM
NUMBER VOLUME
RESULTS FOR aEVATION 2590.00 (M)
DAM LIVE DEGREE TUNNa COST STORAGE REGULATION COST
TUNNEL
DIAMETER
UNREG
aow
REG
FLOW
3
0.5816
10.7466
39.9937
0.4809
0.0000
0.0000                 0.0000                 11.1065
4
5.0229
44.0373
556.3680
0.9142
2.0687
3.8687               -1.3271
8.4279
SYS
5.6045
54.7839
596.3616
0.8089
2.0687
PENSTOCK DESIGN                DIAM (M.)»                 2.1527     HEAD LOSS (M.)= POWER TUNNa DESIGN                    DIAN (M.)=                 2.9212     HEAD LOSS (M.)=
RESULTS FOR ELEVATION 2585.00 (M)
22.6891
COST
(H$)=
12.9438
36.6940
COST
(M) =
21.6987
RESERVOIR DAM
NUMBER VOLUME
MM LIVE DEGREE
TUNNEL TUNNEL
UNREG
REG
COST           STORAGE      REGULATION         COST              DIAMETER aOU
aou
3
0.3843
8.6102            22.5197
0.4467
0.0000              0.0000
4
3.6480
0.0000               9.4335
34.5057
355.1161
0.7834
1.7842
3.5807
-1.3391
6.9456
SYS
4.0323
43.1160
377.6358
0.6871
PENSTOCK DESIGN
DIAM
(MJ=
2.0072 h;
1.7842 LOSS      (M.)=
POWER TUNMEL DESIGN
DiAM
23.2251
37.5608
COST (ND®
(M.J=
2.7238 HI
LOSS (M.)=
COST (M4)=
11.2535
18.3649A-32 ACRES CONSULTING SERVICES LTD                     ALELTU PRE-FtASIBILITY STUDY
ALELTU PRE’EEASIBILITY STUDY OPTIMIZATION GF PROJECT SIZING
TRIXU - JIDA : PEN TIL TO A
RESULTS FOR ELEVATION 2580.00 (M)
RESERVOIR
DAM
DAM
LIVE
DEGREE
TUNNEL
TUNNEL
UNREG
REG
NUMBER
VOLUME
COST
STORAGE
REGULATION
COST
DIAMETER
FLOW
FLOW
3
0.2324
6.8863
11.1503
0.4244
0.0000
0.0000
0.0000
7.1250
4
2.4906
25.5594
204.9839
0.6262
1.3410
3.0787
-0.5266
4.7611
SYS               2.7230            32.4457           216.1342            0.5189              1.3410
PENSTOCK DESIGN           DIAM   (M.)=            1.7797 HEAD LOSS (M.)=                  24.1762    COST (Ml)=             8.8474
rovn TUNNEL DESIGN                 DIAN   (M.)=           2.4151 HEAD LOSS (NJ=
39.0989    COST (Ml)=           14.8310
RESULTS FOR ELEVATION 2598.35 (M)
RESERVOIR DAM
NUMBER VOLUME
DAM
COST
LIVE DEGREE TUNNEL STORAGE REGULATION COST
TUNNEL
DIAMETER
UNREG REG
FLOW FLOW
3               1.0196             15.1920           86.6824              0.5724              0.0000             0.0000             0.0000            13.7153 4               7.7889              60.4596     1018.5537                1.0000             2.4551             4.2287            -2.3760             10.5273
SYS               8.8085             75.6517     1105.2361                0.9989              2.4551
PENSTOCK DESIGN          DIAM (M.)=              2.3564       HEAD LOSS (M.)=          22.0148       COST (M1) =      15.5094 POWER TUNNEL DESIGN          DIAM (M.)=              3.1977       HEAD LOSS (M.)=          35.6035       COST (Mf)=        26.0003A-33
ACRES CONSULTING SERVICES LTD
ALELTU PRE-FEASIBILITY STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OF PROJECT SIZING TRIXU - JIDA : PEN TIL TO A
SUMMARY OF RESULTS
ELEVATION
(K)
DAM COST
TUN COST
PTUN COST
PSTX COST
PWRH COST
TOTAL COST
(IM)
(IM)
(M)
(IK)
(IM)
(IM)
2610.00             105.5762                 2.2325               26.0242                15.5237
2605.00               92.7819
2.3455               26.0242                15.5237
94.3972 243.7538
94.1288 230.8041
2600.00               79.8879                 2.4336               26.0242                15.5237                93.8604                217.7298
2595.00 67.1355
2590.00 54.7839
2585.00 43.1160
2580.00 32.4457
2.2957               24.1789                14.4231
87.6689              195.7021
2.0687 21.6987 12.9438 79.6154 171.1104
1.7842 18.8649 11.2535 70.7014 145.7200
1.3410               14.8310
3.3474                58.5811                116.0462
2598.35               75.6517                 2.4551               26.0003                15.5094                93.6945                213.3110A-34
W3ES CONSULTING SERVICES LTD ALELTU PRE-FEASIBILITY STUDY
ALELTU PK-EEASBILITY STUDY
OPTIMIZATION OF PROJECT SUING
TILIXU - JIDA : PEN TIL TO A
SUMMARY OF RESULTS
ELEVATION
(M)
NET HEAD
CAP COST
ANN EGY
ANN BEN
CAPACITY
(N)
AUS COST
AVG COST
KARG COST
(N)
(»N/YI;
(GW)
•$N)
($/KW)
(MILS/KVH)
(MILS/KWH)
BEN/COST
RATIO
2610.00 1009.39
2605.00 1006.14
2600.00 1002.39
29.25              1013.04
27.79              1009.23
26.22              1005.51
23.57                913.73
20.61 305.35
17.55 680.92
35.46 289.11
35.32 233.04
35.19 236.96
32.16 262.20
23.20 229.93
23.33 194.33
843.12
301.31
753.74
746.40
744.02
749.88
23.93                410.07               1.2079
27.54                417.31               1.2710
26.08                 417.%                1.3423
2595.00
2590.00
2585.00
997.93
993.12
987.96
25.65
25.57
25.77
25.61 1.3645
26.63 1.3633
20.14 1.3531
2530.OG                 931.72                     13.97               511.04                  17.39                145.84                 795.69                  27.34                  22.15                1.2799
Z98.35                1001.14
25.69               1003.19
35.11                286.30
745.07
25.61
24.32                1.3669I ADI t A. I
Kt  Sill  IS  UF  INI  11  Al
LAmil MUOtl RUHS
l>«sc i lul loti
Unit
3A
MA
5A
45A
34 5A
56C
56C
568
56A
5689C
56890
5689A
9G
Wl
6896
68911
(1)
(2)
(31
(4)
(5)
(6)
(7)
(81
(91
(10)
(ID
(12)
(13)
(14)
(IS)
(16)
full Supply iovol
a
2 574.U
2 578.0
2 600.0
2 597.5
2 582.2
2 592.0
2 592.0
2 592.0
2 592.1
2 582.5
2 582.5
2 582.5
2 579.1
2 577.2
2 579.1
2 577.5
I IvU SI04 <XJM
57.6
III.7
191.1
290.3
217.6
824.0
625.6
826.2
628.4
1 282.5
1 283.9
1 281.3
231.1
190.3
935.1
815.2
Dvj ol Ruyulal lun
1
97.9
99.5
01.1
92.1
73.6
99.8
99.9
99.9
99.9
99.9
99.9
99.9
93.7
88.1
99.9
95.0
Huju1 d 1 ad f 1 co
1.06
2.02
4.71
6.22
5.76
14.86
14.87
14.87
14.88
22.64
22.65
22.64
4.52
4.25
16.69
16.01
Pu««f 1 annul
a
0.61
1.06
1.53
1.72
1.68
2.58
2.56
2.56
2.50
3.09
3.07
2.99
1.52
1.52
2.66
2.68
0I.M1OI
Pufibfoch Dldnutur
a
1.53
2.02
2.91
3.27
3.17
4.76
4.76
4.87
4.76
5.70
5.70
5.70
3.97
2.78
5.00
4.91
l«ul lludd
a
1 029.6
1 036.7
1 024.7
1 026.4
1 046.1
919.9
815.3
935.5
1 032.2
917.3
933.1
1 034.1
916.0
786.9
925.1
792.5
tout yy
GWh/yr
79.6
153.0
352.3
466.1
440.3
998.7
994.3
1 016.4
1 122.3
1 517.5
1 544.2
1 705.4
302.7
244.7
1 128.0
927.1
( opaci t y
MW
18. 17
34.93
60.43
106.42
100.53
228.02
227.00
232.06
256.24
346.47
352.60
389.37
69.12
55.88
257.54
211.68
Uaas
lx IQ6
28.53
59.01
49.25
64.66
78.82
62.58
62.68
62.71
62.85
99.82
99.89
99.75
26.06
23.23
75.81
69.12
Sui Ixu I urinal $
UI06
0.00
1.88
0.00
2.35
11.18
2.75
1.69
2.75
2.75
26.49
26.50
26.48
0.00
0.00
24.10
23.37
Huvoi lutinul
IxlU6
0.53
0.83
8.27
10.35
1.88
13.16
16.38
16.68
21.22
18.72
23.72
30.16
4.42
3.27
12.89
9.65
Pt»IH tuck
S a 10*
2.36
4.70
6.47
10.76
10.09
11.71
11.71
11.31
22.74
16.80
16.22
32.58
6.96
3.14
21.30
9.77
Huwur house
lx IO6
21.26
25.45
36.63
43.32
41.85
74.30
74.04
75.08
80.78
103.91
105.20
114.06
42.37
38.83
89.46
77.78
lulol Cost
IxlU6
52.68
91.26
72.86
131.44
143.61
164.49
166.50
168.53
190.30
265.73
271.53
303.04
49.81
68.46
223.58
189.68
Annual Cost
6
|xlO /yr
6. 54
10.99
6.77
15.83
17.32
19.61
20.05
20.29
22.92
32.00
32.70
36.47
9.61
8.24
26.92
22.64
Annual Uunol1t
6
ixl0 /y<
2.39
4.59
10.57
13.96
13.21
29.96
29.83
30.49
33.67
45.53
46.33
51.16
9.06
7.34
33.84
27.01
A,y (opacity Cust
1/kW
2 900
2 613
90C
1 235
1 431
721
733
726
743
767
770
778
1 153
1 225
668
896
Awcj tnurijy Cos 1
al 1Is/kW-h
79.72
71.63
24.89
33.96
39.33
19.83
20.17
19.97
20.42
21.09
21.17
21.40
32.75
33.69
23.87
24.64
Ah j t nut yy Cos 1
al Ils/kWh
66.87
77.69
19.15
30.00
30.00
30.00
30.00
30.00
29.34
29.73
29.64
28.76
30.00
30.00
29.96
50.00
UA Hallo
-
0. 38
0.42
1.21
0.88
0.76
1.51
1.49
1.50
1.47
1.42
1.42
1.40
0.94
0.89
1.26
1.22A-34
■M3E3 CONSULTING SciVICES LID ALELTU P8E-FEAS3ILITY STUD!
ALELTU PBE-cEA3ISILITr STUDY uPTINIZATION OF PROJECT SIZING TILDOJ - J IDA : PEN TIL TO A
SUMMARY OF RESULTS
ELEVATION
(M)
me: head
(N)
CAP COST
itt/YS)
ANN EGY
(GUH)
ANN BEN
(IN)
CAPACITY
(MV)
AUG COST
il/KV)
AUG cos:
(MILS/KUH)
MARG COST
(MILS/KWH)
bem/cos:
RATIO
2610.00 1009.39
2605.00 1006.14
2600.00 1002.39
29.35              1013.04
27.79              1009.23
26.22              1005.51
23.57                913.73
20.61 305.35
35.46                289.11                 343.12
35.32                233.04                 301.31
35.19                236.96                 753.74
32.16 262.20 746.40
23.20 229.93 744.02
23.98               410.07               1.2079
27.54               417.31                1.2710
26.03                417.%                1.3423
2595.00
2590.00
997.93
993.12
25.65
25.57
25.61 1.3645
26.63 1.3633
Z85.00
987.96
17.55
630.92
23.33
194.33
749.83
25.77
20.14
1.3581
2530.00
931.72
13.97
511.04
17.39
145.84
795.69
27.34
TT '.e
*1J
1.2799
2598.35                1001.14
25.69               1003.19
35.11                286.30
745.07
25.61             •a^aUaa                1.3669AlJlt A,
Hl MH IS Of INI I I Al LAYOUl MOOtI RUNS
Dus<r Ipl Icmi
Unll
3A
34A
5A
45A
34 5*
56C
5«3
56A
5669C
56890
5689A
9G
®l
689G
68911
(II
(2)
<31
(4)
(5)
(6)
(7)
<8>
(91
(10)
(II)
(12)
(13)
(14)
(15)
(16)
full Supply Lovul
■
2 574 <,0
2 578.0
2 600.0
2 597.5
2 582.2
2 592.0
2 592.0
2 592.0
2 592.1
2 562.5
2 582.5
2 562.5
2 579.1
2 577.2
2 579.1
2 577.5
I Iva SIcmojm
Mh>3
51.6
III.7
191.1
290.3
217.6
824.0
825.6
626.2
626.4
1 282.5
1 263.9
1 281.3
231.1
190.3
935.1
815.2
Dwy ul Regulation
97.9
99.5
81.1
92.1
73.6
99.8
99.9
99.9
99.9
99.9
99.9
99.9
93.7
88.1
99.9
95.0
l<U <J U 1 d 1 U(J fl CM
.Vs
1.06
2.02
4.71
6.22
5.76
14.86
14.87
14.67
14.68
22.64
22.65
22.64
4.52
4.25
16.69
16.01
Pcmuf 1 annul
■
0.81
1.06
1.53
1.72
1.68
2.58
2.56
2.56
2.50
3.09
3.07
2.99
1.52
1.52
2.66
2.68
UI^buIui
Punstock Dlaroutur
HI
1.53
2.02
2.91
3.27
3.17
4.76
4.76
4.87
4.76
5. 70
5.70
5.70
3.97
2.78
5.00
4.91
Nut Ikiod
HI
1 029. 6
1 036.7
1 024.7
1 026.4
1 046.1
919.9
815.3
935.5
1 032.2
917.3
933.1
1 034.1
916.0
786.9
925.1
792.5
GN-h/yr
19.6
153.0
352.3
466.1
440.3
998.7
994.3
1 016.4
1 122.3
1 517.5
1 544.2
1 705.4
302.7
244.7
1 128.0
927.1
Capac 11y
HW
16. 17
34.93
80.43
106.42
100.53
228.02
227.00
232.06
256.24
346.47
352.60
389.37
69.12
55.88
257.54
211.68
l)«m^
Im IO6
28.53
59.01
49.25
64.66
78.82
62.58
62.68
62.71
62.85
99.82
99.69
99.75
26.06
23.23
75.61
69.12
IxlO6
0.00
1.88
0.00
2.35
11.16
2.75
1.69
2.75
2.75
26.49
26.50
26.48
0.00
0.00
24.10
23.37
P<mui I annul
Im IO6
0.55
0.83
8.27
10.35
1.88
13.16
16.38
16.68
21.22
16.72
23.72
30.16
4.42
3.27
12.89
9.65
IO6
2.36
4. 70
8.47
10.76
10.09
11.71
11.71
11.31
22.74
16.80
16.22
32.58
6.96
3.14
21.30
9.77
PcMUf IiuuSm
lx IO6
21.26
25.45
36.83
43.32
41.85
74.30
74.04
75.08
80.78
103.91
105.20
114.06
42.37
38.83
89.48
77.78
lutdl Cost
Im IO6
52.68
91.26
72.66
131.44
143.81
164.49
166.50
168.53
190.30
265.73
271.53
303.04
49.81
68.46
223.58
189.66
Annual Cost
6
Im IO /yr
6. 34
10.99
8. 77
15.83
17.32
19.81
20.05
20.29
22.92
32.00
32.70
36.47
9.61
8.24
26.92
22.64
Annual Banal 1t
6
i*IO /yf
2.39
4.59
10.57
13.98
13.21
29.96
29.63
30.49
33.67
45.53
46.33
51.16
9.08
7.34
33.64
27.81
Avy LapaC 1 1 y Coil
l/k»t
2 ‘>00
2 613
906
1 235
1 431
721
733
726
743
767
770
778
1 155
1 225
868
696
Av<j lnu(<jy Cost
•1 1 Is/kM’li
79. n
71.83
24.89
33.96
39.33
19.63
20.17
19.97
20.42
21.09
21.17
21.40
32.75
33.69
23.87
24.64
Mui j £nu< yy Cos t
ml 1 |s/ktf*t)
66.87
77.69
19.15
30.00
30.00
30.00
30.00
30.00
29.34
29.73
29.64
28.76
30.00
30.00
29.96
30.00
HA Kat Io
-
0.38
0.42
1.21
0.88
0.76
1.51
1.49
1.50
1.47
1.42
1.42
1.40
0.94
0.89
1.26
1.22iadli a. 2
IKSill  IS  (N  FIHAI
IA10UI MOit I RUHS
Doser 1 pI Ion Unit
5A«
(II
6A
(2)
%A 568A 561
(3> <41 ?5
B9A I
89G
(61
456A
171
45689A          256A«»          7E°«
56.I2A            5689.I2A        5689.I4A
(6)
(9)                  (10)
(III
7l2)
(13)
full Supply level
■
2 600.0
2 595.1
2 598.4
2 597.4
Dam Vuluaw
2  598.7
Mm*
2 599.0
l.l
2 598.7
6.0
2 598.6
2 628.0
8.8
9.6
|o  .7
2 500.0
2 601.2
2 600.2
2 596.9
I Ivo Slur agu
Ha*
1.8
99.0
8.9
10.7
706.2
1.6
0.1
I 105.2
| JO5.2
I    579.2
10.1
11.7
10.0
D«*j ol Rtejulallon
4/2.9
1
59.64
1 127.1
1 596.1
100.00
143.0
1.00
1 325.6
1 800.9
1 883.9
Hegu1 a 1 wd flow
100.00
100.00
10 0.00
3.32
100.00
8. 16
100.00
100.00
13.72
16.14
20   .40
100.00
-
100.00
100.00
■
6.69
100.00
Power lunnwl
1.74
14.19
20.88
2.56
2.30
6.70
3.20
5.4)
).   79
17.71
24.41
26.60
Dlaawlur
2.35
3.25
5.85
-
2.55
5.66
4.09
4.25
Penstock 1)1 .mm 1 ar
■
1.28
1.89
Mel lh«ad
2.36
2.53
•
2.  79
969.4
1.75
9U0.4
2.39
2.82
2.50"
I 001.|
| 001.8
I    004.6
1.75
2.63
3.02
1 007.1
3.13
Lnur gy
Ot-h/yr
240.2
950.6
584.2
1 001.7
1 004.9
i ooi.r
786.5
1 005.4
1 006.7
Capaclly
I 005.2
I 181.3
I    496.1
MW
68.50
464.9
1 038.6
166.80
1 552.7
168.0
505.2
286.50
357.10
42  7.50
1 300.5
1 796.0
1 956.3
132.70
296.40
457.40
46.00
110.00
571.10
512.50
558.30
Dears
Im IO6
17.49
54.01
Sni lace tunnels
75.65
86.22
lx IO6
94   .93
24.48
62.42
101.58
15.58
2.46
8.55
18    56
27.58
116.28
135.60
120.61
Power lunnul
lx IO6
7.71
4. 18
22.02
3.73
20.05
1.03
-
26.00
29.89
36   .56
2.95
20.84
31.43
Puns loch
lx IO6
4.60
7.25
9.95
26.77
57.27
2.49
25.51
17.83
21   .81
2.99
32.56
42.62
45.8/
Power house
IxlO6
59.25
8.37
65.80
15.97
22.25
2.21
8.37
93.69
12  9.00
19.50
25.42
27.36
total Cost
lx IO6
106.40
69.06
63.26
149.76
96.22
131.47
9.62
213.31
248.89
50 0.86
57.60
114.91
150.26
161. 70
107.53
225.12
312.60
30.95
96 50
265.68
374.74
596.97
Annual Cost
6
lx to /yr
8.32
18.05
Annual Uonuflt
6
IxlO /yr
25.09
29.9/
8.41
56  .25
12.95
27.11
20.45
37.64
3.72
11.62
34.43
35. 11
52  .43
46.13
46.60
Avg Capacity Cost
l/KN
41.55
1 008
16.27
36.35
53.64
5.88
15.48
62.86
745
4 38
70 4
68.47
Av J Lliurgy Cost
890
45.52
mlllS/kW'h
34.63
811
760
30.87
715
644
8/7
770
7)1
693
Moi g lnur <jy Cost
■Ills/kWIi
25.61
25.37
25.54
24   .18
27.85
26.10
27.47
24.56
22.14
30. 17
26.4/
U/V Hallo
24.62
30.46
-
1.01
50  .22
25.13
25.82
33.84
24.44
29.93
1.13
-
-
23.23
28.29
26.22
1.37
1.58
|.  45
1.26
1.34
1.43
1.58
1. 16
1.21
1.39
1.47
• Nunop 11mai.
■■ Situ 2a - Scheme 2.
■••Situ 7a Scheme |,
Wosurbl data a< u given except whor u underlined. Robl-Gunxxo date ai w given except were underlined.APPENDIX B
TABLE OF CONTENTS
LIST   OF   TABLES LIST OF PLATES
Page
Bl - INTRODUCTION----------------------------------------------------------------------------- B- 1
B2 - DATA AVAILABILITY AND REVIEW------------------------------------------------- B- 3
B2.1 - Hydrometric Station Locations and
Records--------------------------------------------------------------------  B- 3
B2.2 -        Streamflow Data Analysis------------------------------------------------------ B-17
B2.3 -        Rainfall Data             Analysis------------------------------------------------  B-25
B3 - PRELIMINARY STREAMFLOW SEQUENCE ANALYSIS ------------------------  B-28
B3.1 -
Evaluation 
of Discharge Stations -----------------------------------  B-28
B3.2 -
Generation 
of Inflow Sequences-------------------------------------  B-31
B3.3        -        Assessment        of        the        Regulation        Potential
of Each Reservoir--------------------------------------------------------  B-31
B4 - FINAL STREAMFLOW SEQUENCE ANALYSIS ------------------------------------  B-33
B4.1 - Derivation of Synthetic Flow Sequences--------------------------------------      B-34
B5 - EVAPORATION ANALYSES-------------------------------------------------------------  B-39
B6 - RESERVOIR REGULATION ANALYSIS ----------------------------------------------  B-52
B7 - FLOOD FLOW STUDIES----------------------------------------------------------------- B-53
B7.1 -
General --------------------------------------------------------------------------  B-53
B7.2 -
Frequency Curves--------------------------------------------------------------- B-60
B7.3 -
Homogeneity Test -------------------------------------------------------------  B-62
B7.4 -
Flood Index Factors ------------------------------------------------------------ B-62
B7.5 -
Mean Annual Floods ----------------------------------------------------------  B-63
B7.6 -
Peak Flood Calculations-------------------------------------------------------  B-63
B7.7 -
Inflow Hydrograpns -----------------------------------------------------------  B-65
B8 - RESERVOIR SEDIMENTATION ------------------------------------------------------  B-67
B9 - EVALUATION OF HYDROLOGIC ANALYSES -----------------------------------  B-67
B9.1 - General ---------------------------------------------------------------------------  B-67
B9.2 - Inflow Sequences ---------------------------------------------------------------  B-69
B9.3 - Flood Flows ---------------------------------------------------------------------  B-70
PLATESAPPENDIX B
LIST OF TABLES
Number             Title
B. 1                    Streamflow Records
B. 2                    Rainfall Records
B.3                     Discharge Record Corelations
3.4                     Complete and Extended
Streamflow Records
B. 5                   Rainfall Corelations
B.6                     Comparison of Chacna and 
Muger Streamflow Parameters
B.7                    Centroid         Distances         of         Subbasins in Preliminary Hydrology Study
B.8                    Montnly         Inflow         Sequences of Subbasins
B.9                     Reservoir Evaporation Losses B. 10                  Example Jida Reservoir
Regulation Computer Runs
B. 11                 Reservoir-Regulation for Final Model Runs
B. 12                 Results       of       Flood Hydrology Analysis
B. 13                  Flood Index Factors B. 14                 Computed Peak Flows
RelationshipsAPPENDIX B
LIST OF PLATES
Number           Title
B-l                   Hydrologic Data Base
B-2                  Hydrometric Recording Station B-3                  Hydrology Studies-DetaiIsAPPENDIX B
HYDROLOGICAL STUDIES
Bl - INTRODUCTION
This appendix contains a description and the results of the hydrological studies carried out for the Aleltu project. 
These studies were carried out in two phases as hydrologic
data were required initially to facilitate operation of the
layout optimization model and at a later stage for execution 
of the prefeasibility studies.
-    Initially, no rainfall data were available, and streamflow records only were utilized to provide a data base for preliminary hydrologic analyses. A simplified spatial relationship was defined between project subbasins and relevant gauging stations. On this basis, monthly reser
voir inflow sequences were derived.
-   As more data became available, including rainfall data, further studies were undertaken to refine the results of
the preliminary analyses. Evaporation losses from the proposed reservoirs were determined and flood hydrology studies were carried out. A qualitative assessment of potential reservoir sedimentation was undertaken.
A numDer of hydrologic methods were used and various analyses were carried out to obtain reliable series of monthly inflow sequences for the subDasins of the project. In orcer to 
maintain a perspective on the approach and methodologyAPPENDIX B
HYDROLOGICAL STUDIES
Bl - INTRODUCTION
This appendix contains a description and the results of the hydrological studies carried out for the Aleltu project. 
These studies were carried out in two phases as hydrologic
data were required initially to facilitate operation of the
layout optimization model and at a later stage for execution 
of the prefeasibility studies.
- Initially, no rainfall data were available, and streamflow records only were utilized to provide a data base for preliminary hydrologic analyses. A simplified spatial relationship was defined between project subbasins and relevant gauging stations. On this basis, monthly reser
voir inflow sequences were derived.
- As more data became available, including rainfall data, 
further studies were undertaken to refine the results of
the preliminary analyses. Evaporation losses from the proposed reservoirs were determined and flood hydrology studies were carried out. A qualitative assessment of potential reservoir sedimentation was undertaken.
A number of hydrologic methods were used and various analyses were carried out to obtain reliable series of monthly inflow sequences for the subbasins of the project. In order to 
maintain a perspective on the approach and methodologyB-2
descrioea      in      Sections      B2      to      B6,      a      point      form      summary      of      study steps and results is presented oelow.
(a) No streamflow data are available at the sites under
study in the Aleltu project. Available streamflow recording stations are located at the (more drier) eastern side of the project area (Chacha) and at the (more wetter) western side of the project area (Muger). 
Additional stations are located outside the project area.
(d) No correlation exists among the Chacha and Muger stations and correlations with outside stations is not strong.
(c) There are no rainfall stations witnin the subbasins but
a number are located around tne peripnery of the project area. The availaDle rainfall records are mostly incom plete, intermittent and snort.
(d) No consistent correlative relationships exist between 
any pair of rainfall stations. This is likely due to spot rainfall, typical of convective thunderstorms and line squall activity; therefore, longer records cannot be used to fill in or extend the shorter records.
(e) No reliaole correlative relationsnips between streamflow records and any of the rainfall records could be derived. The density of rainfall station locations is insufficient (for the type of rainfall experienced) to extend or fill in streamflow records from rainfall recordings.
f) As a result of tne absence of reliable correlations
among any of the streamflow or rainfall records, synthe tical streamflow sequences were derived for the suboasins.READ
PLATE A
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY ALELTU HYDROELECTRIC PROJECT
COMPUTER MODEL FLOW CHARTi
4r
* FW M
r» 4 k t r a* ’ *
• ♦ « ►*-> **
< W 1 • i«M » n* * •«* &
-e
*     »   < MS
♦
»< t*WMrf
*•♦ W
•* AM *
< *rvr
MWV"»■•
r. in < I . *■*
»     • ■ * »,    «i
.•ent.
<
iC*B-3
(g) The method of synthetizing flow sequences uses
-   annual isohyetal maps to obtain an estimate of the mean annual rainfall in each subbasin
-   probabilistic methods to derive a rainfall/runoff relationship from data of the Chacha and Muger stations
- a statistical, single-step, sequential, simulation method with a random element to derive streamflow values for each subbasin from the monthly flow variability recorded at the Chacha station.
(h) The results of the analyses are considered to be accept able for examining alternative development schemes at prefeasibility level. The reference hydrology will, 
however, require extensive review once actual streamflow observations at the top ranking sites have been 
collected for a number of years.
B2 - DATA AVAILABILITY AND REVIEW
B2.1 - Hydrometric Station
Locations and Records
The locations of streamflow and rainfall stations of interest in the Aleltu study are shown on Plate B-l. Tne recording periods of these stations are shown on Plate B-2. The individual records of the streamflow and rainfall gauging stations are shown in Taoles B.l and B.2.table   Pl   :   historic   STREANFLOU   sequence    foe    peressa    r.uer    at    pepre
DRAINAGE AREA«211 RmJ
BIBHAN IN MILLION CUBIC METRES
JAN
FEB MAR
ABRIL
MAY
JUNE
JULY
AUG
SEPT
OCT
NdV
1962
0.32
0.27
0.50
0.55
0.60
0.91
—
......
1963
0.43
1964
0.20
0.29
0.35
o.io
1.15
2.10
22.79
1.02
45.63
27.36
19.36
65.69
1.73
0.00
1.30
1965
0.22
0.71
0.51
0.65
1.12
1.12
0.63
0.35
0.04
2.13
0.91
42.50
49.04
12.20
1966
0.47
0.60
0.62
1.12
1.13
0.06
1.13
1.69
24.35
0.99
0.10
0.35
1967
5.63
1.20
0.61
2.02
0.52
1.04
1.42
2.87
50.38
22.57
I960
50.06
0.87
1.0(1
1 .47
29.92
0.60
1.41
DEC
0.75
0.09
0.23
2.90
0.63
1969
2.90
1.15
0 . 19
1.32
1 .no
1.44
1.30
1.00
1.32
60.92
6.24
57.83
7.21
14.40
2.07
0.42
34.53
3.40
1970
3.14
0.41
0.27
0.67
0.37
0.64
0.54
109.06
3.71
0.53
1971
0.29
0.15
0.20
0.40
0.70
34.05
5.53
63.50
7.57
0.3*3
0.93
1.32
2.0(3
0.42
1972
22.23
110.01
0.25
0.38
0.34
0.40
0.27
0.36
0.34
0.90
9.24
0.41
1973
0.36
0.40
0.33
0.27
0.24
H.40
48.06
12. 15
1974
0.06
0.39
0.43
1975
0.26
0.33
0.40
0.52
0.53
0.51
0.40
20.6/i
0.57
60.22
42.17
19.97
0.60
0.46
0.33
0.25
52.77
13.71
1976
0 33
0.50
0.29
1.10
15.22
57.92
1.27
0.34
0.36
0.52
0. 13
0. 1 ]
40.47
1977
0.40
0.44
0.70
0.35
1U. 40
76.44
0.92
15.07
0.65
0.46
0.52
0.25
0.31
tu
1970
0.45
0.20
0.32
0.24
0.54
0.40
0.44
0.46
0.55
24.90
0.55
27.95
0.53
1.30
1.07
4.32
I
4^
1979
0.55
0.29
0.33
0.50
1.05
16.26
1.04
46.12
0.0 1
10.00
24.26
3.82
1900
0.50
0.46
0.42
0.75
0.16
0.24
0.34
0.33
0.33
0.25
31.66
4.00
2.57
44.96
0.72
35.68
0.09
0. 13
0.20■
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s-aTABLE Bl               HISTORIC STREAMFLOW SEQUENCE FOR AWASH RIVER R MBLKA KUNTURE IN MILLION CUBIC METRES DRAINAGE AREA-444O Ka2
JAN
FEB
MAR
APRIL
MAY
JUNE
JULY
AUG
SEPT
OCT
NOV
DEI
1963
2.67
2. IK
1 .31
12.10
34.49
22.43
109.09
375.84
204.31
18.36
6.56
5.96
1464
4.20
1.74
2.40
5.50
4.15
19.62
147.04
239.11
276.42
59.01
X
X
1965
X
X
X
X
X
X
X
X
X
X
X
X
1966
2.93
16.9 1
4.35
15.00
2.42
17.92
150.42
454.97
303.22
26.79
7.D7
4.30
1967
2.02
3.35
1.05
16.44
31.59
17.97
153.69
364.26
109.40
70.03
44.46
9.52
1960
3.15
11.72
5.94
50.33
10.02
22.01
179.06
242.60
156.31
41.47
7.50
7.58
1969
11.01
11.12
23.10
12.60
19.67
40.71
240.37
493.59
259.00
24.55
16.36
8.99
1 970
2.69
9.31
23.30
10.65
2.09
12.91
302.37
490.74
276.53
05.01
10.12
6.01
1971
6.22
2.90
1.60
7.46
10.93
95.94
309.33
520.01
348.92
43.67
9.40
13.04
1972
5.00
12.33
9.53
13.30
12.77
0.77
181.69
234.92
68.32
12.02
5.36
3.42
1973
6.60
1.60
0.69
0.32
4.60
13.57
120.04
380.30
286.31
53.33
9.65
6.10
1974
6.23
2.52
9.15
7.92
3.67
9.00
166.50
410.04
167.95
39.13
0.00
3.91
1975
3.64
2.50
1 .41
5.44
1.09
1.04
309.27
343.52
445.58
54.51
7.41
3.76
1976
2.79
1.22
4.28
2.03
0.30
10.04
119.37
3 16.06
132.11
105.00
7.36
3.41
1977
9.35
4.30
X
4.00
5.42
10.75
164.60
155.00
154.75
05.43
116.57
8.66
1970
4.63
6.95
6.43
5.23
4.64
21.32
159.13
350.49
170.76
36.39
0.36
5.75
1979
6.19
7.60
9.65
7.66
11.22
13.95
139.03
257.53
98.30
23.73
9.02
5.29
1 q30
2.56
2.07
5.22
3.20
2.07
16.73
200.02
371.06
129.69
16.40
4.17
2.20
NOTE: X Mistin') ditaTAM E r<J
URA1NAGE AREA-489 Mm2
HISTORIC STREAMFLOW SEQUENCE FOR HUGER RIVER AT CHANCHO IN MILLION CUBIC METRES
.IAN
FEB
MAR
ABRIL
MAY
JUNE
JULY
AUG
SEPT
OCT
NOV
DEC
1962
0.62
0.40
0.53
0.44
0.76
1.26
0.60
37.3)
51.02
11.02
2.24
1.38
196 3
0.D4
0.72
0.50
1.13
1.70
1 .61
66.37
91.70
35.50
3.37
1.00
0.80
196 4
0.47
0.30
0.27
0.25
0.22
1.53
30.10
50.57
50.39
11.14
2.00
1.42
1965
0.42
0.19
0.16
0.28
0.17
0.36
7.67
25.91
16.56
6.89
1.00
0.49
1966
0.20
0.32
0.23
0.57
0.19
1.07
22.50
90.20
36.21
10.73
0.95
0.48
1967
0. 19
0.29
0.31
0.32
1 .50
0.68
25.43
115.16
55.09
21.49
9.10
5.62
I960
4.50
4.0«
1.B6
4.63
2.(14
2.26
25.80
51.91
33.05
6.68
1.54
0.7B
1969
0.75
0.91
2.21
0.99
1.33
4.48
42.00
X
X
X
1.24
0.6)
1970
0.56
0.56
1.70
1.00
0.44
0.61
9.42
X
35.35
5.62
1.24
0.78
1971
0.55
0. Ji
0.42
0.65
0.69
1.02
38.11
79.73
33.73
6.12
1 .59
0.85
1972
0.47
0.52
0.60
0.71
0.67
0.7(1
55.38
117.05
26.36
2.40
0.68
0.45
1 973
0. 16
0.16
0.17
0.10
0.31
1.63
36.77
135.5)
06.02
12.on
1.26
0.59
1974
0.34
0.24
0.36
0.50
0.29
1.50
67.09
90.36
42.22
4.74
0.90
0.37
1 975
0.2 1
0.16
0.17
0.50
0.2 1
2.65
94.93
126.20
69.61
7.72
1.09
0.51
1976
0.40
0.20
0.29
0.36
0.62
1.55
72.54
80.92
38.33
2.41
1.07
0.51
1 977
0.94
4.96
0.20
0.32
0.49
3.10
125.08
141.37
79.56
43.93
35.69
12.79
1970
5.28
4.04
4.69
3.08
3.94
3.72
42.64
72.48
66.07
16.56
1.55
0.99
1979
1.01
0.0 1
0.47
0.57
0.92
1 . 16
H4.65
X
60.34
6.33
1.18
0.77
1900
X
X
X
X
X
X
X
X
X
X
X
X
NOTE: X - Missir.3 daf aTABLE 82 : Monthly Total Rainfall in mm
Hy<Jrolo3ic il Period: 1973-1982
STATION: Addie Ababa Observatory
JAN
FEB
HAk APRI
L
MAY
E
JOLY
AUG       SEPT
OCT
NOV
HEC
1973
1974
1975
1976
1977
1978
1979 1900 1981 1982
0.3
1.6
2.2
33.6
138.8
.0
267.7
345.5      269.0
50.3
0.0
52.5
0.0
31 .9
21 .7
0.9
60.3
94.8
65.9
00.3
84.9
114.2
53.5
113.3
.5
264.9
330.0      329.2
3.5
0.0
0.0
0.0
2.7
□ 4.4
.5
271.5
183.6       1U2.0
17.0
0.0
0.0
19. 1
61.4
44.0
.7
101.2
277.7       145.5
3.0
62.1
13.2
55.7
40.0
68.0
146.0
30.8
103.2
.6
255.3
280.6       133.6
272.3
1.2
0.0
2.1
63.3
10.1)
.7
200.1
361.3      111.0
39.1
0.0
3.4
127.9
19. 1
73.6
1.1
316.1
204.5       225. 1
0.0
0.0
16.2
aa. a
36.6
45.3
00.5
02.9
>.2
385.1
297.4       111.9
51.5
0.0
0.0
0.0
75.5
176.0
3.9
1.1
266.5
320.9       102.1
12.6
0.0
4.8
40.7
00.9
57.0
103.7
115.9
1.9
259.3
257.9       109.1
64.4
4 1.2
11 .9
CO
no:
X^Nissing data
I
00
I
■TABIE 02 : Monthly Total Rainfall in mm.
Hydrological Period: 1962-1979
STAY KiN: Lheno
JAN
FEB
MAR
APRIL
MAY
•
JULY
AUG
SLPT
OCT
NOV
HEC
1 962
X
X
X
X
X
0
332.0
173.0
127.7
1 963
X
4 .3
10.2
12.5
07.1
X
54.0
4.9
1
270.3
477.2
443.0
0.0
1964
13.(1
16.3
46.0
14.0
04.0
44.2
14.2
5
330.2
246.0
126.7
16.6
0.0
1965
7.9
0.0
73.7
56.0
0.0
11.3
0
202.7
520.6
22.3
17.9
41.5
0.0
1 966
P.7
63.6
14.0
35.0
0.0
0
391.9
574.0
135.5
0.0
1 96 7
0.0
0.0
57.3
0.0
00.2
0.0
39.2
5
0.0
0.0
93.0
46.7
60.3
0.0
I960
0.0
51.0
14.6
155.6
60.0
0
354.3
214.2
95.6
12.1
21.9
1969
54.3
93.7
0.0
131.0
151.4
64.3
7
320.6
351.1
29.5
1.0
5.1
1970
25.6
75.5
52.5
0.0
42.0
0.0
0
295.3
227.0
100.0
10.0
2.1
1 971
6.4
0.0
79.1
41 .7
70.7
2.6
2
270.2
312.9
73.9
7.0
5.1
31.3
1972
4.7
17.3
29.6
95.0
44.9
1
107.2
169.2
79.2
3.0
0.0
3.2
197 3
1.3
0.0
0.0
20.2
22.7
6
202.5
323.6
94.9
23.5
1 .1
12.4
J 974
6.7
15.3
51.5
5.7
54.1
1
324.2
163.9
02.5
2.2
X
X
1975
0.5
15.7
27.7
97.6
37.5
9
304.6
103.7
123.1
5.7
0.0
11 .7
1 976
7.6
0.0
10.4
69.3
76.2
9
265. 1
293.3
74.5
2.6
34.7
4.2
1977
52.5
34.4
19.9
46.6
61.1
0
303.6
250.0
45.3
110.0
13.7
0.0
1970
0.0
60.0
45.5
47.4
29.0
9
207.9
314.0
131.4
44.7
0.0
0.0
1979
92.2
14.4
H4.7
24.4
3.2
6
250.3
207.7
79.4
15.1
0.0
0.0
NO:      X»Mi 55 ing dataTABLE 82 : Monthly Total Rainfall in mu
Hylrol O'jic il Period: 1962- 1979
JAN          FEB          MAR      APR II
STATION: Sendafa
JUNE JULY AUG SEPT OCT NOU
1962
1963
1964
1965
1966
1 967
1960
1969
1970
1971
1972
1973
1974
1977
1978
1979
XXXX
26.0 79.0 7.0 141.0 31
X 10.5 196.6 205.0
.0 79.7 383.7 430.0
8.4            8.3          37.7         79.3          39 .5 25.3            0.0          10.1          31.3            7 . 4
0.0        141.8          25.6       140.3          96 . 0
0.0            4.0          82.0       155.1        112 .3
0.0          49.1            0.0           0.0          (1 .6
60.7          69.8         9.3.4         74.1            6 .6
00.4          39.1          71.4        57. 1          13 .9
3.7          10.2        169.1       100.6        272 .2
16.0        205.6          320.3
114.9 227.1 396.9
171 .9 293.5 522.4
33.2       2d(l. 6         176.6
04.7        443.7          113.2
117.1        279.3         27 4.2      134.4            37.4              0.0
177.4 34.0 1.0
80.9             0.1              1.3
05.4           43.9           32.1
71.8           19.7              0.0
60.5           20.0            45.2
](t6.6 10.1 0.0
09.6             3.1              6.0
48.3        319.9          666.3     208.1               9.3              0.0
405.8 354.1 66 4.9 260.4 43.2 8.7
33. 1             0.0          55.0       107.9         94
0       162.4        279.0          333.2
0.0            0.0            0.0         13.0         63 . s
62.3        217.1          465.6
0.0            0.0          87.0           0.5         93
.3        123.8        266.2          210.7      116.3               0.0                X
73.2             1.0            12.0
175.8 0.0 0.0
08.9          21.4          22.0         42.4          73 .4
145.1        390.9          359.2     262.1          165.1             10.0
0.5          86.5          49.1         33.8         46 133.7            8.6          02.3         56.2         01
4       155.6        264.6          289.0      109.7            80.2              0.0
. 1 111.3 429.4 256.9 132.8 13.5 0.0
8EI
24.0
20.0
36.3
0.8
0.0
0.0
0.0
0.0
0.0
22.0
12.0
3.0
X
0.0 ® 0.0
X
NB:      X = M i n « i ng data
0T-TAB! 1. B2 5 Monthly Total Rainfall in
Hydrological Period: 1972-1979
STATION: Ochre Perhan
JAN
run
MAK
APRIL
HAY
JUNE
JULY
AUG
SLPT
OCT
NUM
HEC
1972
X
19.0
33.3
57.7
11.0
X
219.7
150.6
H2.1
0.0
0.0
0.0
1973
6.1
0.0
0.0
32.3
79. 1
27.6
394.0
365.5
116.1
19.9
1974
0.0
4.9
00.3
0.0
0.0
15.7
39.0
149.0
299.5
X
X
X
X
1975
0.0
11.1
97.9
9.5
0.0
X
102.5
194.0
J20.7
102.5
0.0
0.0
0.0
1976
0.0
0.0
95.0
X
X
73. 1
212.1
245.7
19.0
13.5
15.0
5.5
1977
30.2
12.3
29.0
X
X
X
1111.3
336.8
36.5
107.4
X
0.0
1970
0.0
25.2
36.6
17.3
31.1
41.0
172.3
200.4
124.1
32.7
0.6
0.0
1979
01.1
7.4
66.0
71.0
69.7
50.2
J55.7
131.9
102.5
X
0.0
6.5
NR:
X=Hissing data
IT-TABLE B2 : Monthly Total Rainfall in ox
Hydrological Period: I960 J979
STATION: Mendida
JAN
FEB
MAX
APRIL
HAY
JUNE JULY AUG SEPT OCT NOV PEC
I960
1961
X
X
1962
1972
X
X
50.2
23.0
30.7
113.7
0.0
X
0.0
X
59.2
X
75.7
0.0
40.5
86.6
369.0
465.2
70.5
X
310.1
316.2
131.0
91.3
X
X
0.0
X
X
X
X
X
1974
1975
35.0
X
271.3
200.9
236.6
148.0
90.3
36.2
X
X
56.9
X
X
X
X
0.0
26.2
0.0
63.9
01.0
0.0
31.0
120.4 24.2
185.5
29.6
359.9
257.9
X
210.4
44.0
65.0
X
0.0
X
X
X
0.0
1976
1977
3.0
97.7
40.0
12.7
X
25.1
82.6
X
X
21.5
65.0
66.4
330.0 21)9.1
252.5
401.7
62.4
81.3
16.0
43.4
21.0
X
0.0
0.0
1 978
1 979
0.0
97.0
64.0
4.5
10.7
51.0
0.0
47.0
X
44.6
X
260.9
217.6
55.2
97.0
40.2
X
X
X
X
0.0
X
25.8
X
HH:
X-Mivilri'i dataHy > lroIogic11 Period: 1969-1979
JAN           FEB          MAR          APRIL        MAY        JONE         JULY            AUG          SEPT            0( T             NOV            HEC
1 96 9
63.2
X
X
X
11.4
X
533.5
434.4
X
0.5
4.0
0.0
1970
40.0
X
X
X
4.0
20.0
370.5
534.7
X
7.3
0.0
4.0
1972
X
X
X
X
X
166.2
146.0
X
97.7
X
X
X
1 973
X
X
0.0
69.0
X
54.0
332.1
460.5
157.9
50.0
11.5
30.3
1 974
0.0
14.9
109.0
0.0
157.7
197. 1
439. 1
305.4
144.5
6.6
0.0
0.0
1975
0.6
43.1
40.0
□ 7.0
91.0
109.0
309.0
357.7
226.5
X
0.0
X
1 976
0.0
X
15.0
19. 1
68.2
59. J
541.0
390.6
1 47.6
0.0
49. 1
3.7
1 977
3 .3.4
37.9
34.1
27.1
50.0
03.0
599.9
319. 1
X
1 970
221.9
0.0
0.0
X
56.0
29.0
40.2
1.1
109.7
X
X
163.7
63.8
1 979
79.9
23.4
66.6
X
X
134.2
69.2
361 .:)
15.9
X
X
X
X
X
X = M i f»s i ng d it aTAD1.E 1<2 : Monthly Total Rainfall in me
Hydrological Period: 1972-1979
STATION: Chancho
JAN           FEB          MAR          APRIL        MAY         JUNE         JULY            AUG         SEPT            OCT           NUM            [(EC
1972
X
X
X
X
X
103.6
264.4
191.6
03.9
X
32.2
31.7
1973
0.0
0.0
4.0
16.0
52.3
180.3
290.6
320.5
107.1
0.7
0.5
0.7
197 4
0.0
19.0
91.3
9.5
70.2
133.6
190.0
216.0
00.6
9.0
0.0
4.2
1975
15.7
22.0
35.4
07.9
113.7
169.9
351.7
244.5
50.5
0.0
1 .0
27.5
1976
7.5
39.9
64.1
93.9
23.1
245.4
290. 1
X
X
X
X
X
1977
51.1
21.7
109.2
50.9
31.4
215.4
377.4
270.5
95.9
165.7
12.4
X
197(1
X
X
X
45.4
11.5
X
356.0
391.0
200.5
9.3
X
20.2
1979
90.0
19.3
60.7
X
119.7
123.6
270.0
136.3
X
X
X
X
X = Mtasing datiTAPLE P2 : Monthly Total Rainfall in mm.
Hydrological Period: 1974-1982
STATION: Sululta
JAN
FEP
MAR
APRIL
MAY
JUNE
JULY
AUG
SEPT
01 T
NOV
IIF.C
1974
X
X
X
X
97.4
134.1
271.3
231.2
107.0
6.0
0.0
0.0
1 975
0.0
2.5
27.0
□ 7.6
70.6
128.9
361.1
295.6
148.0
10.2
0.0
0.0
1976
38.0
17.0
52.9
80.9
117.4
182.7
448.2
310.5
59.6
18.0
57.3
11.5
1 977
109.5
23.5
37.4
61.1
70.4
241 .9
378.0
290.8
130.1
174.7
0.0
0.7
1978
2.0
36.4
40.5
16.7
17.3
174.0
298.1
251.2
133.1
41 .0
0.4
0.2
1979
144.9
27.3
25.3
15.2
3.3
65.9
302.4
267.1
105.0
7.1
0.0
2.5
1980
10.1
31.8
70.0
33.8
14.6
79. 1
353.0
522.3
228.5
7.7
X
0.0
1901
0.0
0.0
122.8
68.7
183.4
57.5
395.5
418.5
77.1
2.0
0.0
1.3
1982
35.5
36.9
62.6
79.7
109.9
92.2
277.1
269.6
93.3
28.5
52.7
X
HP:
X'Hiffirig data
tnTABLE M2 : Honthly Tuld) Kain/al 1 in mm
Hydrological Period: 1970, 1974
STATION: Mehle-Ttige
JAN
FEB
MAM
APRIL
MAI
JUNE
JULY
AUG
SEPT
OCT
NUM
HEC
1970
X
X
X
X
X
X
220.0
X
X
X
X
X
1974
X
X
X
X
X
X
X
101 . 1
147.0
X
X
X
Monthly Total Maintal 1 in mm.
STATION: Muketuri
Hydrological Peilod: 1970
1971        1974
IAN           FEB           MAk        APR 11         MAY        JUNE         JULY           AUG        SEPT           OCT           NUM           MEI
1970
1971
1974
X
16.5
X
X
10.4
X
9.0
X
61.1
X
97.2
X
50.5
X
276.3
X
X
404.0
134.3
X
5.7
X
24.9
12.4
77.1
X
X
X
X
X
X
160.7
155.6
X
X
X
Monthly Totjl Rainfall in mm.
IlyJrol o'jiljI Period: 1925 1979
STATION: Meneba
JAN
LEK
MAk
APk 11.
MAY
JUNE
JULY
AUG
SLPT
OCT
NUM
HEC
1975
X
X
X
X
X
140.7
290. (1
261.4
226.0
65.0
0.0
0.0
19 '6
0.0
0.6
10.6
X
X
X
353.3
.166.5
50.0
120.6
0.0
32.3
1977
90.7
13.6
41.. 0
56.0
39.0
X
X
X
57.1
76.1
X
X
1 97U
X
47.7
19.3
40.9
0.0
91.9
X
101.2
07. 1
0.0
2.5
9.1
- - — ■ — - - - — - . — - - - —
Nl<:       X-Mi eci ng data
1 979
66.7
57. Ic
32.9
411.7
9) . 4
X
43.3
122.3
X
X
X
30.0
________B-17
There are 11 rainfall stations and 4 streamflow gauging 
stations near the Aleltu project area. From Plates B-l and 
B-2, and Tables B. 1 and B.2, it can be observed that
- rainfall stations do not exist within the main Aleltu Basin 
area
-    rainfall data are mostly incomplete with poor overlap of
recording periods, with the exception of the Addis Ababa, 
Sendafa and Sheno stations
-    three streamflow stations are located at the eastern and 
western side of the Aleltu Basin and a fourth station is
located just south of Addis Ababa. Although some data are
missing, the records of these stations are generally 
complete, show a good overlap and extend over a period of
about 20 years.
-    three new streamflow stations were installed during July
1983 for the purpose of the Aleltu project studies; these
stations are located on three of the main rivers in the
project development area. Overlapping data with other
stations, however, were not available in time for
incorporation in this report.
B2.2 - Streamflow Data Analysis
The        discharge        records        of        the        following        gauging        stations        were analyzed
-    Chacha River at Chacha
-    Beressa River at Debre Berhan
-   Awash River at Melka Konture
-   Muger River at Chancho.J
B-18
The records of these stations are shown in Table B.l.
Beressa Station
The record of the Beressa station is complete and contains 19 years of monthly historic streamflow data from 1962 to 1980.
Chacna Station
The record of the Chacna station contains flow measurements from 1962 to 1980 with some months missing during 1968, 1969 and 1980. Estimation of flows during these months was carried out using the following relationships.
Sum A - Sum M
Sum SD
where
F ,p = characteristic factor for wet or dry period 
n
"p" of year "n"
Sum A = sum of available flow in period "p"
Sum M = sum of the mean monthly flows in 
period "p"
Sum SD = sum of the standard deviations in period "p" and
Flow = M + m
F x SD
n,p              mB-19
where
Flow      =      estimated      flow      in      month      "m,"      period      "p"      of      year      "n" M   = mean of recorded flows in month "m"
m
SDm = standard deviation of recorded flows in month "m"
Muger Station
The       record       of       the       Muger       station       contains       18       years       of       obser vations with some months missing during 1969, 1970 and
1979.              Flows      in      these      months      were      estimated      using      the      same technique as for the Chacha station. For the entire year
1980,      however, no recordings are available. To extend the data, corelations with the other discharge records were carried out. The results in Table B.3 indicate that none
of these correlations provide a reliable basis for extend
ing data. However, because of lack of better data and in view of the preliminary nature of the analysis, it was
decided to accept the Muger versus Beressa relationship in order to extend the Muger discharge record.
Awash Station
The record of the Awash station contains 17 years of data with some months missing in 1964 and 1977. These data were filled in using the same technique as for the Chacha
station. However, the entire records for 1962 and 1965 are missing. Corelations witn the Beressa, Muger and Chacha stations were carried out as snown in Table B.3. The corelation with the Beressa River was selected as the most suitable for data extension and the missing Awash data were estimated on this basis.
The complete 19-yr historic and extended streamflow sequences of the four gauging stations are shown in Table B.4.*
B-20
TABLE B.3
DISCHARGE RECORD CORELATIONS
Corelations
Muger versus Chacha
Number of Data Points
14
Corelation Coefficient
2
(r )
-0.081
Standard Error       of Sample
(SE)
5.37
Standard Error       of the Mean (SE/ «^n)
1.44
Muger versus
16
0.222
7.47
1.87
Beressa
Muger versus
11
-0.055
18.86
5.69
Awash
Beressa
15
0.502
23.63
6.10
versus Awash
Chacha versus                 12 Awash
0.510
82.96
23.95TAKI    L    B4    :    HISTORIC    STREAKF1    (IU    SEQUENCE    FOR    BERESSA    RIMER    AT    DEBRE    H1RHAH    IN    MILLION    CUBIC    METRES URA INAGE AREA 21 1 |t»2
a
IAN              FEB            MAR           APRIL          MAY         JUNE         JULY
AUG         SEPT           OCT           NOV           BEL         :              ANNUAL
TOTAL       MEAN
1 962               0.32            0.27            0.50             0.55            0.60            0.91            22.79        45.63          19.36            1.73            1.30          0.75
1 96 3 0.43 0.20 0.35 1.15 2.10 1.02 27.36
196 4 0.29 0.10 0.22 0.71 0.51 0.65 42.58
1 965               0.63             0.35            0.04            2.13            0.91             1.12              1.13
1966               0. 47            0.60            0 62             1.12            0.06            1.69              5.63
1 967              0.6 1            0.52            1 .04           1 . 42          2.117           1.47            29.92
1960                1.00             1.4)             1.15            1.32           1 . 44           1.80            60.92
1 969 2.90 0.39 1 . UO I . 30 1.3.1 0.42 34.53
1970                0.41             0.27            0.67            0.37            0.64            0.54            34.05
1 97 1              0.29            0.15            0.20            0.40            0.70            5.53            22.23
197 2               0.38             0.40            0.27            0.36            0.34            0.90              6.40
94.71            7.09
197 J
0. u             0.37            0.24            0.3.3            0.52            0.51            20.66
197 4               0.39             0.36            0.40            0.53            0.40            0.57            42.17
1 975               0.3.1            0.25            0.33            0.50            0.29            1.10            15.22
1 97 6              0.13            0.11             0.40            0.44            0.78            0.35            18.40
1 97 7              0.46           0 . >1            0.20            0.24            0.40            0.46            24.90
1 970               0.45          0.32            0.54            0.44            0.55            0.55            16.26
1 97 9              0.55            0.29            0.33            0.50             1.05            1.04            24.26
1900                0.16            0.24            0.34             0.33            0.33            0.25              4.80
65.69            0.00            1.12            1.12          0.09
49.04          12.28            0.99            0.35          0.23
24.35            0.10            1.20           2.02          2.90
58.36 22.57 0.07 0.60 0.63 50.06 6.24 7.21 2.07 1.32 57.83 14.40 3.40 3.14 2.08
109.06              3.71            0.53            0.30          0.42 63.58            7.57            0.93            0.25          0.34
110.01              9.24            0.41            0.36          0.48
48.06          12.15            0.86            0.43          0.34
60.22          19.97            0.60            0.46          0.36
52.77          13.71            1.27            0.52          0.52
57.92          40.47            0.92            0.65          0.25 76.44          15.07            0.53            1.07          0.46 27.95            1.30           4. 12           0.03          0.42 46.12          18.00            3.02            0.50            0.75 31.66            2.57            0.72            0.09          0.13 44.96          35.68            5.39            0.52            0.20
109.51 9.13
10U.U3 9.07
46.26            3.86
94.04            7.04
105.55 8.00
150.85 12.57
156.92          13.00
109.62            9.14
150.DO          12.57
72.89            6.07
104.47 8.71
1)3.51            9.46
110.39            9.87
114.18            9.52
62.03            5.17
80.30            7.36
63.19            5.27
93.20            7.77
U3
I
bJ
MEAN 0.56 0. 39 0.56 0.75 0.08 1.11 24.02
I-LOU
56.91          14.24            1.94            0.92            0.75       :
103.02
0.58
STU.
0.60             0.30            0.42            0.52            0.66            1.16           1 4.82        22.68          10.33            1.94            0.86            0.80
OEM
C . 01 1.079 0.775 0.753 0.685 0.755 1.052 0.617
VAR
X 0.54 0.38 0.54 0.73 0.85 1.07 23.31
0 ISTR I8UT ION
0.390 0.726 1.000 0.937 1.071
55.25 13.82 1 .08 0.09 0.73
S 29.76 2.48
:            0.289          0.289
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lilf A INAGE AKEA-418 Kiu2TAU1 E U4                 HISTORIC ANU EXTENUEU STREAMFLOW SEQUENCE FOR AWASH RIMER V MELKA KUNTURE IN MILLION CUBIC METRES
hRAJNAGE AREA=444O Cm2
JAN            FEU           MAR          APRIL          NAY         JUNE          JULY           AUG         SEPT            OCT           NOM           UEC         •               ANNUAL
TOTAL       MEAN
1962                3.60A         4.50A         6.30A         6.40A         6.10A                        19.00A187.50A332.20A269.75A     40.30A        15.20A           6.00A
•
•
1 963              2.67            2.10            1.31          12.18        34.49          22.43       189.09       375.84          204.31           18.38            6.56            5.96 196 4              4.28           1 .74           2.40            5.50            4.15        19.62       147.04        239.11          276.42          59.01              9.65A         5.65A
•
•
•
896.85v 74.74e
875.40             72.95
•           774.57v           64.55c
) 965
4.90A     14.30A       12.30A         29.00A     10.90A     23.20A 81.00A246.05A155.70A
32.80A       23.50A         14.30A
•
• 1007.12 U3.93
647.95e           54.00e
1 966              2.93          16.93            4.35        15.00              2.42        17.92       J50.42        454.97          303.22          26.79            7.87            4.30
1 96 7             2.02            3.35            1.05         16.44          31.59        17.97       153.69       364.26           189.40          70.03          44.46            9.52
I960               3.15         11.72            5.94          50.33        10.02              22.0)    179.06        242.60          156.31          41.47            7.58            7.58
I 96 9           11.01           1112          23.18          12.60        19.67             48.71    240.37        493.59          259.00          24.55          16.36            8.99
1970              2.69           9.31          23.30          10.65            2.09           12.91    302.37        490.74          276.53          85.01          10.12            6.01
) 971              6.22            2.90            1 .68           7.46          16.93            95.94   368.33          520.01        340.93          43.67            9.40         13.D4
1972              5.0U         12.33            9.53          13.30          12.77              8.77   181.60        234.92             88.32          12.02            5.36            3.42
1 973 6.68 1.60 0.69 0.32 4.60 13.57 120.04 300.30 206.31 53.33 9.65 6.10
197 4 6.23 2.52 9. 15 7,92 3.67 9.06 166.50 418.04 167.95 39.13 0.08 3.91
1975 3.6 4 2.50 1.41 5.44 1.09 1.84 309.27 3-43.52 445.58 54.51 7.41 3.76
•
•
•
904.5U            75.36
•
•
•
•
•
•           737.77             61.48
1169.15 97.43
1339.73      103.31
•           1457.30      121.45
•
• 507.50 48.96
883.19             73.60
•
•
•
•
••
842.9(1 70.25
1180.77 98.40
I
K)
UJ
1976
2.79
1.22
4.2(1
2.63
6.38
18.04
119.37
336.86
132.11
105.80
7.36
3.41
742.45
61.87
J 977
0 . 15
4. 10
17.75A
4.00
5.42
18.75
164.60
155.08
154.75
05.43
116.57
0.66
•■
743.66V
61.97e
1 970
4.63
6.95
6.43
5.23
4.64
21.33
159.13
350.49
178.76
36.39
8.36.
5.75
••
780.09
65.67
1 979
6.19
7.60
9.65
7.66
1 1.22
13.95
139.83
257.53
90.30
23.73
9.02
5.29
••
••
509.97
49.16
1 900
2.56
2.07
5.22
3.20
2.07
16.73
208.02
371.06
129.69
16.46
4.17
2.20
765.15
63.76
MEAN
4.72
6.31
7.72
11.34
10.26
22.24
108.85
348.17
2)6.91
45.73
17.20
6.56
••
686.0)
73.83
I LOU
STU.
3.31
4.09
6.99
11.45
9.62
20.04
74.69
101.22
92.02
25.83
25.72
3.30
••
231.97
19.33
OEM .
( . 0!
0.489
0.775
0.905
1.010
0.938
0.901
0.395
0.291
0.428
0.565
1.496
0.503
••
0.262 0
.262
MAE
X
0.53
0.7)
0.87
1.28
1.16
2.5)
21.31
39.30
24.40
5. 16
1.94
0.74
••
100.00 X
HISTR(BUT ION
note: a L 3 ti■aIedTABLE U4               HISTORIC ANU EXTLNDEU STREAMFLOW SEQUENCE FOE HUGER RIVER AT CHANCHO IN HILLION CUBIC HETRES I'RAINAGE AREA»489 Kh2
JAN          FEU          HAH       APRIL         HAY
JULY AUG 6EFT OCT NOV
DEL :
ANNUAL
TOTAL MEAN
1962           0.62          0. 40         0.53            0.44         0.76
1963           0.04          0.72          0.50            1.13         1.70
1964           0.47          0.30          0.27            0.25         0.22
1965           0.42          0.19          0.16            0.30         0.17
1966           0.20          0.32          0.23            0.57         0.19
1967           0.39          0.39          0.31            0.32         I .58
1960           4.50          4.00            1.06          4.63         2.04
1969            0.75          0.91          3.21            0.99         1.33
1970           0.56          0.56            1.70          1.00         0.44
1 971           0.55          0.31          0.42            0.65         0.69
1972           0.47          0.53            0.60          0.71         0.67 197 3          0.36          0.16          0.17            0.10         0.31 197 4           0.34          0.34            0.36          0.50         0.29 1975           0.2 1         0.16            0.17          0.50         0.23 1976           0.40          0.20            0.29          0.36         0.62 1977            0.94           4.96           0. !0          0.33         0.49
1970           5.28          4.04            4.69          3.08         3.94 1 979           1 .01         0.0 1           0.47          0.57         0.92
1900           0.45A        0.43A          0.29A       0.46A       0.55 A       1.30 A             35.70A 75.58A   41.35A            7.83A        0.64A
1.26             6.60       37.31       51 .02        11.02             2.24
1 .61          66.37       91.70       35.50             3.37           1 .00
1.53           30.10       50.57       50.39         11.14             2.00
0.36             7.67       25.91        16.56             6.69           1 .00
1.07           23.50       90.20       36.21         10.73             0.95
0.60           25.43     115.10       55.09         21.49             9.10 2.26           25.60       51.91       33.05             6.60           1.54
4.48           42.08       02.35A     45.25A        11.90A         1.24
0.61             9.42       53.95A    35.35             5.62           1 .24
1.03           30.11       79.73       33.73             6.12           1.59
0.70            55.38     117.05       26.36             2.40           0.68
1 .63          36.77     135.51       06.02         13.00             1.26 1.50           67.09       90.36       42.22             4.74           0.90 2.65           94.93     126.20       69.61             7.72           1.09 1.55           72.54       08.92       38.33             2.41           1.07 3.10         125.00    141 . 37      79.56         43.93          35.69 3.73           42.64       72.46       66.07         16.56             1.55 1.16           H4.65   120..18A     60..14            6.3.)          1 . 10
1.38
0.08
1.43
0.49
0.48
5.62
0.78
0.61
0.78
0.05
0.45
0.59
0.37
0.51
0.51
12.79
0.99
0.77
0.55A
115.511 9.63
205.22 17.1 1
148.66 12.39
60.10            5.02
163.65 13.64
225.40 19.62
139.93         11.66
194.lOe 16.18m
111.31            9.28
164.5/ 13.71
206.07              17.17                                         1
W
275.04 22.92
200.91 17.41
J04.00          25.33
207.20          17.27
440.51          37.36
225.84      111.62
27*2.6 le       23.22m 165.13e   13.76m
to
lU
MEAN
Fl OW
STU.
BEV.
C. 01
VAR
0.99           1.03          0.82           0.93          0.94           1.74        46.89        86.67         47.47         10.47           3.48           1.62
1 . 40         1.51          J . 12         1.21           0.99           1.00        31.54        33.31         18.20           9.42           8.02           2.94
•
•
203.06          16.92
U5.29           7.11
1.4)5         1.459         1.368          1.292        1 .04(1       0.620         0.673        0.304         0.383         0.900         2.306       1.813         •           0.420         0.420
X               0.49
U 1STfc 1 BIJT ]()N
0.51           0.40           0.46           0.46           0.86        23.09         42.68         23.38           5.16           1.71           0.60       •         100.00 Z
NOTE: A EstimatedB-25
B2.3 - Rainfall Data Analysis
Rainfall Isohyet Map
To estimate the long-term average annual rainfall on the subbasins of the Aleltu project, a rainfall isohyet map was prepared from the small-scale isohyet maps of the meteoro logical atlas of Ethiopia and the data in Table B.2. The
long-term mean annual rainfall was calculated for each rainfall station and plotted on a project area map. The
data from the rainfall stations were used to supplement the available isohyet contours and the isohyet map was redrawn specifically for the project area. Plate B-l shows the estimated rainfall isohyets over the project area.
Comparison of
Rainfall Stations
From Plate B-l, it is observed that rainfall stations are not available within the Aleltu project area, but there are a number of rainfall stations located around the project area. These stations are
-   Addis Ababa Observatory
-   Chancho
-   Debre Berhan
-   Debre Tsige
-   Deneba
-   Fiche
-   Mendida
-   Muke Turi
-   Sendafa
-   Sheno
-    Sululta.B-26
Generally, most of the data sets of these stations are
incomplete with single month and/or series of months or
years missing. The Debre Tsige, Deneba and Muke Turi
records, containing fewer than 6 years of data, were
omitted from the analysis. The remaining stations have
record lengths varying between 8 and 18 years but these do 
not all have overlapping time periods.
Annual,        seasonal        and        monthly        corelation        analyses        were carried        out        between        the        rainfall        stations.        The        results        of these       analyses       are       snown       in       Table       B.5.       The       incompleteness of      the      records      results      in      a      lack      of      overlapping      data.      For the     cases     where     an     overlap     of     more     than     2     years     was     avail able,      no      corelation      could      be      found      between      any      pair      of      the stations.          These          results          are          particularly          surprising          for the       Sendafa       and       Sheno       stations,       which       are       located       within 35     km     of     each     other     and     have     record     lengths     of     18     years, with       13       years       overlapping.       Apparently,       there       is       a       large spatial        variation        in        rainfall        in        the        Aleltu        project        area with       spot       rainfall       patterns       occurring       in       a       random       manner. This         situation         is         consistent         with         rainfall/storm         systems dominated by line squall and thunderstorms.
Monthly corelations were also carried out. From these, it was established that corelations appear to exist only for some of the dry months of most of the stations, which likely results from lack of rainfall during these months and these are therefore of little value.B-27
TABLE B.5
RAINFALL CORELATIONS
Station
Years of
Record
Results of Corelation Analysis
Annual
Seasonal
Sheno  Wet
(18 yr)
—
Sendafa  D
(18 yr)
Fiche                 10
Addis
Ababa
10
Sheno
(18 yr)
no over
lapping
data
n = 6
r 2 = 0.15
no over
lapping
data
n - 3
r 2 » -0.99
n = 5
r 2 = 0.18
n = 2
Sendafa
(18 yr)
no over
lapping
data
n = 3
r 2 = 0.75
no over
lapping
data
n » 2
n = 2
-
-
Mendida             8
——
Deb re
Berhan
8
-
-
Sululta 9
Chancho 8
-
-
no over                  —
-
lapping
data
She no
18
-
-
-
n    =    13
(dry)
r 2 = 0.24
Sendafa
(wet)
18
-
-
n = 14
r 2 = 0.13
-
Note: n
r2
= number of years of data = corelation coefficientB3        PRELIMINARY STREAMFLOW
SEQUENCE ANALYSIS
During the initial phases of the study, rainfall data were
not available and for tne purpose of the preliminary runs of
the layout optimization model, monthly inflow sequences of
the subbasins were calculated based on streamflow records
only. The derivation is described below.
B3.1 - Evaluation of
Discharge Stations
To establish the inflow sequences for each subbasin of the
Aleltu project, the use of one or more of the available
discharge records was required. The selection was based on 
the following evaluation.
The Awash station at Melka Konture has a drainage area which
is about 10 to 20 times larger than that of
basins       or       any       of       the       other       stations.       Also, farthest away from the Aleltu project area.
Konture station, therefore, appears to be least attractive
the Aleltu sub this station is
The Melka
for inflow sequence
generation.
The Beressa station at Debre Berhan has a drainage area of about half tne size of the Muger and Chacha basins. This station is located outside the Aleltu Basin and directly to the east of tne Chacha station, away from the project area. For these reasons, the Beressa station was not further consi dered .
From Plate B-l, it is shown that the annual mean rainfall in the basin varies from east to west. The Chacna station isB-29
located at the eastern end, just inside the Aleltu Basin, 
while the Muger station is located at the western end, also just inside the basin. Both stations have drainage areas comparable in size with the subbasins of the Aleltu project. Therefore, the Chacha and Muger stations appear to be the obvious choice for inflow sequence generation.
However, corelation of monthly flow data between the two stations is poor as shown in Table B. 3 and the use of these stations would not provide a reliable historical data basis.
When the long-term specific mean flows of the stations are compared, however, there appears to be a strong similarity between the specific runoff from these stations as shown in Table B.6.
Also, when the annual discharge records of the Chacha and Muger stations are examined probabilistically, it can be shown that there is a consistent relationship between the two records. This is shown on Plate B-3, Figure 1.
It is therefore concluded that, although there does not
appear to be a deterministic relationship between annual or monthly flows from these basins, long-term average flow con ditions appear to be consistent with drainage area and mean annual rainfall and a probabilistic corelation can be shown to exist. It was considered that, for the preliminary recon naissance analyses, the use of these discharge stations would be acceptable, but that all results would require confirma tion by more detailed hydrologic analyses, including a rainfall/runoff analysis.B-30
TABLE B.6
COMPARISON OF CHACHA AND MUGER STREAMFLOW PARAMETERS
Description
Unit
Chacha
Muger
Recorded annual runoff
Mm3
146.4
203.1
Drainage area
km2
418
489
Mean annual runoff
mm
350
415
Annual rainfall
mm
1 100
1 250
Runoff coefficient
mm/mm
0.32
0.33B-31
B3.2 - Generation of
Inflow Sequences
To account for the variation from east to west of the rain
fall pattern over the basin, preliminary inflow sequences for
the Aleltu subbasins were derived by calculating the dis
tances from the centroid of each subbasin to the Chacha
station as a ratio of the distance between the Chacha and
Muger       stations.       Monthly       flows       over       a       period       of       19       years       were then calculated by computer using the following
relationship.
r ,X x Flow Chacha. ,84-X x Flow Muger., Flo “sub ' “sub x [(84 DA Chacha > + ’“5V ’da MT'ger"1 1
where
Flow = monthly flow
DA = drainage area
X = distance from Chacha station to centroid of subbasin
84        = distance between Chacha and Muger (km)
sub = subbasin
Table       B.7       shows       the       distances       to       the       centroids       for       the       ten subbasins considered in the initial model runs.
B3.3 - Assessment of the
Regulation Potential
of Eacn Reservoir
To establish the relationship between tne degree of flow regulation and the reservoir volume required to maintain that regulation, a monthly reservoir balance was carried out byB-32
TABLE B.7
CENTROID DISTANCES OF SUBBASINS IN PRELIMINARY HYDROLOGY STUDY*
Subbasin
X-Distance**
(km)
Agat
58.0
Tinishu Aleltu
57.5
Tiliku Aleltu
51.5
Jida
37.0
Gomoro
30.0
Robi
19.0
Weserbi
62.0
Duber
57.5
Chacha
0.0
Jinjer
11.5
Muger
-      Lat      09°18*;      Long      38°44'
Distance:
Chacha to
 Muger = 84 km
* Locations: Chacna - Lat 90°32'; Long  39°28'
*’X-Distance is between centroids of subbasins and the Cham* gauging station. 
naB-33
computer analysis. In this analysis, a monthly accounting is
made of change in reservoir storage and spill volumes for the
monthly inflow volumes and for a given constant reservoir
outflow draft rate, according to the following water balance
equation.
Outflow = (Inflow)-(Evaporation)-(Spi11) + (Change in Storage)
Reservoir        evaporation        losses        were        considered        to        be        small        and were not taken into account in the initial model runs.
For each reservoir scheme, the analysis was repeated for
three or more different draft rates. The results were then 
plotted to determine the relationship between the degree of regulation (i.e., the ratio of draft rate to mean annual
inflow volume) and the corresponding storage volumes required to maintain that draft rate without reservoir failure. The reservoir volumes thus derived were used in the layout opti mization model. For comparison purposes, the required live storages at 100% regulation are shown in Table B.ll (see Section B.6).
B4 - FINAL STREAMFLOW
SEQUENCE ANALYSIS
To verify the apparent lack of satisfactory corelations
between individual rainfall records and streamflow records, 
the rainfall/runoff relationships in the Aleltu project area
were investigated. For this purpose, regression analyses of
tne Chacha streamflow record with the Addis Ababa, Sheno andB-34
Debre Berhan rainfall records were carried out. No 
satisfactory corelation between these records, either on an annual, seasonal or monthly basis, could be found.
Obviously, the derivation of reliable inflow sequences for
the subbasins of the Aleltu project cannot be based on the
use of rainfall/runoff regression. Therefore, other statis
tical methods were employed to derive synthetic flow sequences in the manner reported below.
B4.1 - Derivation of Synthetic
Flow Sequences
To make the best possible use of available rainfall and discharge data, synthetic flow sequences were derived from
the Chacha streamflow record, utilizing the 18-yr records of
the Sheno and Sendafa rainfall stations, the rainfall iso
hyets over tne Aleltu Basin and the rainfall/runoff relation ships at the Chacha and Muger stations. A probability
ranking analysis of rainfall and runoff was used to establish 
a means of developing a streamflow sequence with statistical variability typical of the known rainfall variability. The
stepwise methodology employed in the analyses was as
follows.
(a)        Using calculated mean annual rainfall from available rainfall stations, together with the available rainfall
map of Ethiopia, rainfall isohyets over the basin were determined.
(b)       From the isohyets, the mean annual rainfalls of the drainage basins subtending the Chacna and Muger stream flow stations were determined.B-35
(c)             Using       the       Sheno       and       Sendafa       rainfall       records,       average annual          dimensionless          probability          of          exceedance          curves were developed.
(d)      Utilizing the extended and actual discharge records of
the Chacha and Muger stations, the annual discharges were ranked by magnitude and the corresponding probabi lities of occurrence calculated.
(e)       Utilizing these probabilities, the corresponding annual rainfalls for the Chacha and Muger stations over the available period of record were calculated using the curves derived in Step (c).
(f)        The ranked rainfall/discharge relationship using data at Muger and Chacha was derived from the results of Steps (d) and (e).
(g)       The areas of the Aleltu project subbasins were calcu lated from the available topograpnic mapping.
(h)       Utilizing the statistics of the discharge record at
Chacha (i.e., monthly means, monthly standard deviation and monthly serial corelation coefficients) and the drainage area of the subbasins, a series of monthly discharge records for each subbasin, based on the Markov single-step generation method, using single-seeded ran dom numbers was developed. The annual and long-term mean annual runoffs of the generated series were then calculated.
(i)       From the rainfall isohyets, the expected mean annual rainfall at the centroid of each subbasin was determined and, from the rainfall/discharge relationship of
Step       (f),       the       expected       long-term       mean       annual       runoff       was estimated.B-36
(j)        The generated monthly discharge records were adjusted linearly by the ratio of the expected long-term mean annual runoff to the generated long-term mean annual runoff.
The foregoing steps are elaborated in the following 
paragraphs.
(a)       The rainfall isohyets of the Aleltu project area are
shown on Plate B-l.
(b)       The mean annual rainfall of the Chacha and Muger station areas were determined by drawing detailed rainfall isohyets over the drainage areas and calculating the contribution of the areas between the rainfall isohyets
to the mean rainfall. It was found that the mean annual rainfalls of the Cnacha and Muger station areas are
1,100 and 1,250 mm, respectively.
(c)       Because of their long and complete records, an analysis
of the Sheno and Sendafa rainfall records was carried 
out and the results were utilized to develop average annual dimensionless probability of exceedance curves. It was found that, by omitting the extremely large 1971 Sendafa rainfall, a reasonable statistical relationship 
was found between tnese stations. The 1971 rainfall
had the nignest recorded values in each month from March to September. Such rainfalls were not recorded at any 
of the other rainfall stations and a detailed review of these records is required for future analyses.
In the probability of exceedance curves, the recorded annual rainfalls were calculated as a ratio of the mean recorded value and were plotted against the probability of occurrence. Probabilities were calculated using the following formula.B-37
where
Pi = probability of the ith ranked value of the
series
i = rank of the value in the series
n = total number of values in the series
The two curves for Sheno and Sendafa were averaged and the results are shown on Plate B-3, Figure 2. It is
noted that the area below the curve represents the dimensionless annual rainfall volume expressed as a function of the mean annual rainfall.
(d)       The extended and historic discharge records of the Chacha and Muger are shown in Table B.4. The annual discharges were ranked and the corresponding probabili ties of occurrence were calculated, utilizing the above formula.
(e)        It is noted that the calculated probabilities of the
ranked Muger and Chacha discharges are based on a 19-yr record. To determine the correspondingly ranked annual rainfalls, the probability of exceedance rainfall curve was entered utilizing these probabilities (abscissa) and considering the calculated mean annual rainfalls at the Chacha and Muger gauging stations (ordinate).
(f)        A typical rainfall/runoff relationship for the Aleltu Basin was determined by plotting the ranked rainfall and discharge data calculated in Steps (d) and (e) above. This is shown on Plate B-3, Figure 3.B-36
(j) The generated monthly discharge records were adjusted linearly by the ratio of the expected long-term mean annual runoff to the generated long-term mean annual runoff.
The foregoing steps are elaborated in the following 
paragraphs.
(a)        The rainfall isonyets of the Aleltu project area are
shown on Plate B-l.
(b)       The mean annual rainfall of the Chacha and Muger station areas were determined by drawing detailed rainfall isohyets over the drainage areas and calculating the contribution of the areas between the rainfall isonyets
to the mean rainfall. It was found tnat the mean annual rainfalls of the Chacha and Muger station areas are
1,100 and 1,250 mm, respectively.
(c)        Because of tneir long and complete records, an analysis of the Sheno and Sendafa rainfall records was carried 
out and the results were utilized to develop average annual dimensionless probability of exceedance curves. It was found that, by omitting the extremely large 1971 Sendafa rainfall, a reasonable statistical relationship 
was found between these stations. The 1971 rainfall
had the highest recorded values in each month from March to September. Such rainfalls were not recorded at any 
of the otner rainfall stations and a detailed review of these records is required for future analyses.
In the probability of exceedance curves, the recorded annual rainfalls were calculated as a ratio of the mean recorded value and were plotted against the probability of occurrence. Probabilities were calculated using the following formula.B-37
where
Pi = probability of the ith ranked value of the
series
i = rank of the value in the series
n = total number of values in the series
The two curves for Sheno and Sendafa were averaged and the results are shown on Plate B-3, Figure 2. It is
noted that the area below the curve represents the dimensionless annual rainfall volume expressed as a function of the mean annual rainfall.
(d)      The extended and historic discharge records of the Chacha and Muger are shown in Table B.4. The annual discharges were ranked and the corresponding probabili ties of occurrence were calculated, utilizing the above formula.
(e)      It is noted that the calculated probabilities of the
ranked Muger and Chacha discharges are based on a 19-yr record. To determine the correspondingly ranked annual rainfalls, the probability of exceedance rainfall curve was entered utilizing these probabilities (abscissa) and considering the calculated mean annual rainfalls at the Chacha and Muger gauging stations (ordinate).
(f)       A typical rainfall/runoff relationship for the Aleltu
Basin was determined by plotting the ranked rainfall and discharge data calculated in Steps (d) and (e) above. This is shown on Plate B-3, Figure 3.B-38
It is noted that the plotted rainfall/runoff relation
ship is based on annual data series. It is assumed in 
the analysis below that this relationship is also valid 
for establishing monthly runoff series with a typical seasonal variability as defined by the flow records of the Chacha station.
(g)       The areas of the subbasins were determined from avail- aDle 1:50 000- and 1:250 000-scale topographic maps.
(n) Monthly discharge records for each of the subbasins of
the Aleltu project were derived based on the Markov single-step sequential simulation method and using single-seeded random numbers. For this purpose, the monthly means, monthly standard deviation and monthly serial correlation coefficients of the Chacha discharge record were calculated for use in the Markov recursion formula, shown below.
where
= generated streamflow in month "i+1"
= mean of observed flows in month "j+1" Qi = generated flow in month "i"
Qj = mean of observed flow in month "j"
bj = regression coefficient of month "j+1" in monthB-39
t = random number selected from a normal distribution having a zero mean and unit variance
°j+l = standard deviation of observed flows for
calendar month "j + 1"
rj = corelation coefficients describing the relation 
of flows for months "j+1” to flows for month n j ■■
From the synthetically generated monthly inflow sequences, the annual and long-term mean annual inflows were determined.
(i) Using the rainfall/runoff relationship determined in 
Step (f), the long-term mean annual runoffs for each subbasin were calculated and were compared to the synthetically derived long-term mean annual runoffs.
(j) The synthetically generated monthly inflow sequences were multiplied by the ratio of the mean annual calculated runoff to the mean annual generated inflow, to arrive at the inflow sequences used in the final layout optimization model runs.
The results of the analyses are shown in Table B.8.
B5 - EVAPORATION ANALYSES
For the preliminary hydrologic analyses, the effects of evaporation losses were not considered. However, for the detailed hydrologic analyses, an estimate of expected reservoir evaporation losses was made.B-40
TABLE B.8
MONTHLY INFLOW SEQUENCES OF SUBBASINS
GENERATED MONTHLY DISCHARGES (nr 3/S)
BASIN NAME: BASIN NO.:
AGAT 3a
DRAINAGE AREA:      92            km 2
PRECIPITATION:       1283        mm/yr
AVG RUNOFF:       430         mm/ yr
RUNOFF COEFF:      oo • 5        7.
DISCHARGE
YEAR        J           F          M          A
MJ
(m 3/S)
J  A S 0 N D /R
1
0.04 0.04
0.04
0.04
0. 03    0. 03
1.1
5.7
2.65
0. 09
0. 04    0.04
0.
0.04 0.04
0.08
0.04
0.00     0. 13
5.9
7.8
2.54
0.04
0. 03    0.02
1.
0.04 0.0.3
0.04
0.03
0. 03    0.00
2.4
5. 7
1. 17
0.09
0.04     0.03
0.
4
0.04 0.04
0. 13
0.07
0. 15    0. 05
1.3
11.1
1.57
0. 04
0. 05    0. 04
1.
5
0.05 0.05
0.02
0.03
0.02     0.00
3.4
5.7
0.42
0. 10
0. 15    0.03
0.
6
0.04 0.04
0.04
0.04
0.05     0. 14
4. 7
25.7
0.82
0. 1 3
0.03     0. 04
2.
7
0.04 0.03
0.04
0.04
0.04     0.02
0. 1
6.9
1.85
0.06
0. 04    0.03
0.
8
0.04 0.03
0.02
0.05
0.08     0.02
8.0
6. 8
0. 45
0. 12
0.04     0.02
1.
9
0.04 0.05
0. 03
0.03
0.05     0.01
0. 1
8.4
1.62
0. 14
0.04     0.04
0.
10
0.03 0.03
0.03
0.06
0.04     0.46
1.3
2.0
1.63
0. 04
0. 15    0. u4
0.
11
0.03 0.03
0.02
0.05
0.04     0.02
2.4
8.6
2.50
0. 14
0. 14    0. 05
1.
12
0.02 0.01
0.04
0.05
0.04     0.04
5.8
4. o
1.83
0. 07
0. 15    0. 04
1.
13
0.04 0.03
0.03
0. 05
0.05      1.32
8. 1
24. 1
1.27
0. 10
0. 04    0. 03
14
0.03 0.03
0. 04
0.05
0.04     2.78
11.4
9.2
_* • 03
0. 12
0.03     0.02
O
15
0.03 0.02
0. 03
0. 03
0. 1 1   2.78
10. 7
9.0
2.88
0.09
0. 02    0.02
o -- ■
16
0.04 0.05
0.05
0. 13
0.07     0. 13
-•. o
6. 5
1.86
0.03
0. 04    0. 04
1.
17
0•03 O.03
0.04
0. 16
0. 1 1   0. 04
3.9
4.5
1.07
0. 10
0. 02    0. 04
0.
18
0.03 0.01
0. 06
0.02
0.03     0.03
5.8
o. 8
1.30
0.08
0.03     0.04
1.
I?
0.03 0.03
0. 05
0.03
0. 07     0.01
1.2
5. 3
i .84
0.09
A. 02    0. 07
n.
20
0.04 0.08
0.06
0. 03
0.04     0.04
4.2
2.8
1.80
0. 09
0. 05    0. 03
0.
AVG
0.04 0.03
0. 05
0. 05
0.06      0. 40
4. 3
8.3
1.71
0. 09
0. 06    0.03
l.
S.D.
0.01 0.02
0.03
0.04
0.04     0.07
3. 3
6. 1
0. 74
0. 03
0.05     O.01
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TABLE B.8
MONTHLY INFLOW SEQUENCES OF SUBBASINS
GENERATED MONTHLY DISCHARGES (m 3/S)
BASIN NAME:
BASIN NO.: DRAINAGE AREA:
AGAT
3a
92
km"'-2
PRECIPITATION:
1293
mm/yr
•
■I
AVG RUNOFF:
430
mm / yr
RUNOFF COEFF:
33. 5
7.
■i
DISCHA
RGE
X
(m 3/S)
YEAR J
A
MJ
J 
A
S
0
ND
r’R
■
1     0.04      0.04      0.04      0.04     0.03     0 ■ Oo       1.1          5.7       2.65       0. 09  0. 04    0.04         0.3
2     0.04      0. 04     0.08     0.04     0.00     0. 13          5.9          7.8       2.54       0. 04  O. 03   0. 02        1.4
3     0.04      0. 03     0.04      0.03     0.03     0.00           2.4          5.7       1. 17        0.09  0.04     0.03       (>. 8
5     0.05      0.05      0.02     0.03     0.02     0.00           3.4          5.7       0. 42       0. 10  O. 15   0. <>3     0. 8
4     0.04
0. 04     0. 13     0.07     0. 15    0.05            1.3       11.1        1.57        0.04  0. 05    0. 04        1.2
6     0.04      0. 04     0.04      0.04     0.05     0. 14
4.7       25.7       0.82        0. 13  0.03     0.04        2. 6
7     0.04      0-03     0.04      0.04      0.04     0.02           0. 1         o.9        1.85       0. 06  0. 04    0. 03       0. 8
0     0.04      0.03      0.02     0. 05     0.00     0.02            8.0          6.8       0. 45       0. 12  0. 04    0. 02        1.3
10      0.03      0.03     0.03      0.06      0.04     0. 46           1.3         2.0       1.63       0. 04  0. 15    u. 04       0. 5
9     0.04      0. 05     0. 03     0. 03    0.05     0.01           0. 1         8. 4       1.62      0. J 4  0.04     0.04        0. 9
11     0.03      0 • 03    0.02     0. 05     0. 04    0.02            2.4         8. 6       2.50       0. 14  0. 14    u. ».'□      1.2
12     O.02     0 • 01    0.04      0. 05     0.04     0. 04           5.8         4. o       1.83       0. 07  0. 15    0. 04       t . 1
13      0.04
14     0.03
15     0.03
16     0.04
17        O.03
ia          0.03
jQ 0.03
Zu 0.04
AVG 0.04
S.D. 0.01
0. 03     0. 03     0. 05     0. 05     1.32
8. 1      24. 1        1.27       0. 10  0.04      0. 03        2.9
0. 02     0. 03     0.03      0. 1 1   2. 73        10. 7         9.0       2.88     <>. 09  0.02     0.02        2. 1
0 03      0. 04     0. 05    0.04     2.78         11.4          9.2       3.03        0. 12  <>. 03  0.02
0.05 0. 13 0.07 0. 13 0.03 0.04 0. Is 0. 11 0.04 n o t 0. 06 0. 02 0.03 0. 03
6.5       1.36        0.03  0. 04    O.»<4      1.0 3.9          4.5        1.07       0. 10  t1.02    0.04         0.3
5.5 5.8 1.30 0.08 0. 03 0.04 1 . 1
n o 3 0. 05 0. Oo 0.07 0.01 1.2 5- 1.84 0.09 0.02 0.03 0.7
0. 08 0.06 0.03 0. 04 0.04 4.2 2.8 1.80 0. 09 0.05 0. 03 0.8
t"i (“) T 0. 05 0.05 0.06 0. 40
0.02 0. 03 0.04 0.04 0.37
4.3          8.3       1.71        0. 09  0 . 06   0.03         1.3 333        6. 1       0.74        0. 03  0. 05    • >. 01B-41
Table B.8
Monthly Inflow
Sequences of Subbasins - 2
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:      TINISHU
BASIN NO.:      4b
DRAINAGE AREA:      37           km ^2
PRECIPITATION:       1231        mm/yr
AVG RUNOFF:      404          mm/yr
RUNOFF COEFF:       32.0        7.
DISCHARGE (m^3/S)
YEAR
J
F
M
A
M
J
J
A
s
0
ND
YR
1
0.02
0.01
0.01
0.06
0.04
0.01
1.9
3.0
0.67
0.03
0.02      0.01
0.5
2
0.02
0.02
0. 16
0.04
0.02
0.03
2.3
2.3
0.84
0.02
0.01      0.01
0.5
3
0.01
0.01
0.01
0.01
0.01
0.01
0.5
2.6
0.44
0.03
0.02      0.02
0. 3
4
0.02
0.02
0.06
0.06
0.04
0.00
1.0
3.4
0.52
0.02
0.01      0.01
0.5
5
0.01
0.01
0.02
0.02
0.02
0.01
2.2
1.8
0. 18
0.09
0.02     0.01
0.4
6
0.02
0.02
0.01
0.01
0.02
0.01
0. 3
5.0
0. 16
0.04
0.02      0.01
0.5
7
0.01
0.01
0.01
0.05
0.04
0.02
1.3
1.8
0.82
0. 10
0.01      0.01
0.3
8
0.02
0.02
0. 16
0.05
0.04
0.03
0. 1
4.3
0.40
0.09
0.01      0.02
0.4
9
0.02
0.01
0.01
0.02
0.02
0.01
1.9
10.2
0.85
0.09
0.06      0.02
1.1
10
0.02
0.02
0.01
0.02
0.03
0.09
1.4
4. 1
0. 15
0.02
0.02      0.01
0.5
11
0.01
0.01
0.01
0.01
0.01
0.01
1.9
3. 1
1.24
0.04
0.01      0.02
O. 5
12
0.02
0.01
0. 15
0.06
0.04
0.03
1. 1
4.3
1. 10
0.03
0.06      0. 02
0.6
13
0.01
0.01
0.07
0. 03
0.03
0.02
1.3
1.9
0.64
0. 03
0.01      0.01
0. 3
14
0.01
0.02
0.01
0.01
0.01
0.01
0.4
1.8
1.01
0.02
0.02      0.01
0. 3
15
0.02
0.02
0.02
0.05
0.04
0.02
2.5
3.0
0.86
0. 03
0.02      0.01
0.5
16
0.02
0.01
0.01
0.01
0.02
0.01
1.2
1.8
0.78
0.04
0.04      0.02
0.3
17
0.02
0.02
0.01
0.01
0.01
0.02
1.9
2.2
1.04
0.08
0.01      0.01
0. 4
18
0.01
0.01
0.01
0.05
0.05
0.02
0.2
1.8
0.70
0.01
0.02      0.01
19
0.01
0.01
0. 15
0.05
0.03
0.2
0.08
1.5
6.6
1.34
0.07
0.02      0. 01
0.3
20
0.01
0.01
0.01
0.01
0.03
0.02
1.4
2.8
0.39
0.02
0.06      0.02
0. 4
AVG
0.01
0.01
0.05
0.03
0. 03
0.02
1.4
3. 4
0.71
0.04
0.02      0.01
0.5
S.D.
0. 00
0.00
0. Ob
0.02
0.01
0.02
0.7
2. 1
0.35
0.03
0.02      0.00B-42
Table B.8
Monthly Inflow Sequences of Subbasins - 3
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME: BASIN NO.:
DRAINAGE AREA:
PRECIPITATION: AVG RUNOFF:
RUNOFF COEFF:
TILIKU
5b
450 knT2 1108 mm/yr 383 mm/yr 0^2 ■ .z.    /■
DISCHARGE (m 3/S)
YEAR
J
F
M
A
M
J
J
A
S
0
N□
YR
1
0. 13
0.32
0.72
0.30
0.24
0.63
30.4
42.0
4. 10
0.34
0.20     0. 16
6.6
2
0. 10
0.20
0.41
0.28
0.60
0.30
17.8
41.4
9.28
0. 15
0.71     0. 15
6.0
3
0. 15
0. 13
0.22
0. 19
0.22
0. 10
26. 1
19. 1
13.02
1.07
0. 12    0. 17
5. 1
4
0.22
0. 16
0.64
0.29
0.24
0.60
4.5
39.2
9.73
0.47
0. 17    0. 16
4.7
5
0. 14
0.08
0. 10
0. 15
0.52
0.44
3.0
70.9
4.95
0. 15
0.23     0.20
6.7
6
0. 18
0. 13
0. 16
0.51
0.39
0.08
11.9
29.4
11.34
0.42
0.52     0. 15
4.6
7
0. 21
0. 17
0.09
0. 42
0.28
0.23
26.6
26.9
0.96
0.26
0.23     0. 18
5.4
8
0. 18
0.81
0.54
0. 35
0.48
0.23
10.5
27.0
14.78
0.50
0.37     0.20
4.7
9
0. 15
0.04
0.27
0. 12
0.21
0. 18
16.0
12.2
10.06
1.22
0. 17    0. 16
3.5
10
0. 17
0.08
0.21
0. 13
0. 13
0.04
0.6
24.0
7.76
0. 36
0.51     0.20
2.9
11
0. 17
0. 12
0.22
0. 18
0.00
0.09
5.4
110.6
12.07
0.37
0.70     0.20
10.9
12
0. 15
0. 12
0. 14
0. 13
0. 16
0. 14
9.9
39. 4
9. 19
0.37
D. 17   0. 19
5.0
13
0.21
0. 22
0. 14
0.29
0. 16
0. 16
20.4
29.8
1.78
1.02
0. 1 1   0. 16
5.2
14
0. 16
0. 1 1
0.21
0. 17
0. 17
0. 18
14.7
28.2
9.74
0. 38
0.09     0. 16
4.5
15
0. 21
0.07
0. 1 1
0.07
0.00
0.45
29.2
61.2
6.02
0.95
0.23     0. 18
8.2
16
0. 15
0.09
0.67
0.36
0.41
0.32
19.2
18.8
2.41
0. 10
0. 18    0. 13
3.6
17
0. 20
0. 20
0. 48
0.37
0.29
0.56
4.0
27.2
0.97
1. 13
0.09     0. 15
3.6
1A
0. 17
0. 19
0. 1 1
0.21
0.37
0.34
3.5
43.3
9.24
0.26
0. 13    0. 12
4.8
19
20
0. 20
0. 15
0.21
0.20
0.22
0. 10
0. 19
0. 17
0.50
0. 17
0. 14
0.09
13.8
02.3
14. 45
0.55
0. 23    0. 14
9.3
34.8
26. 3
4. 76
0.26
0.23     0. 18
5.6
nVU
S. D.
0. 17
0. 22
0.29
0.24
0.29
0.27
15. 7
40.0
8.67
0.52
0.27     0. 17
5.6
0. 03
0.22
0.21
0. 12
0. 17
0. 18
10.7
24. °
3.74
0.35
0. 19    0.02B-43
Table B.8
Monthly Inflow
Sequences of Subbasins - 4
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:       JIDA
BASIN NO.:       6c
DRAINAGE AREA:       749              km 2
PRECIPITATION:       1103         mm/yr
AVG RUNOFF:       342            mm/yr
RUNOFF COEFF:       31.1         7.
DISCHARGE    (m '3/S>
YEAR        J           F          M          A           M          J              J              A              S              0           N           D           YR
1        0.25  0.22      0.29      1.07     0.77      0. 16           26.6        96. 7   20. 45            0.73   0. 93     0.27         12. 4
2        0.24   0.23      0.25      1.05     0.92      0.29             21.0         11.9       4.52           0.56   0.31      0.22           3. 4
3       0. 19   0.20      0.22      0.27      0.33      0. 12         111.5         41.8   19.68             0.68   0.24      0. 16         14.6
4        0.27   0.29      0. 19     0.22      0.32      0.05              1.7        17. 3       5.90          0. 03   0.69      0.25            2.3
5       0. 14   0. 16     0. 33     0. 33     0.31      0. 18           28.7         54.6       8. 05          0.29   0.61      0. 25           7.8
6        0.20   0.20      0.27      0.23      0. 17     0.33            23.2         62.8       7. 39         0. 50   0.99      0.31          9. 1
7        0.34   0.35      0.30      0.23      0.24      0. 16           31.9       127.9   18. 15            1.34   0. 77     0.29          15.2
0        0.29   0.29      0. 12     0. 16     0.20      9. 15           25.9       35. 1    14. 49            1.24   0.99      0.23            7.3
9       0. 19   0. 19     0.30      0.34      0.3018.14                 79.5         36.6   19.63             1.26   0. 12     0. 20         13.0
10        0.30   0.33      0.90      0.45      0.4612.97                 51.3       50. 1    12.27            0. 35   0. 13     0. 12         10.8
11
0.22
0. 16
0. 29
0. 19
0. 18
0.25
21.9
63.9
12
0.22
0.01
0. 11
0. 09
2. 86
0. 46
0. 00
0. 26
0.24
0.25
7.6
36. 1
74. 1
13
0.24
0.26
0. 44
0.27
11.21
0.34
0.72
0. 12
0.23
10. 3
0.24
6.7
14
0. 19
0. 13
52. 4
0.33
0.25
4.97
0.44
0. 14
0. 45
0. 13
0.24
5. 6
8^ ■ 0
15
0.25
0.24
0.23
0.45
1.20
0. 43
n-r -r
42.6
7.26
0.26
0. 17
0.25
11.2
16
0.27
0.21
0.90
55. 1
0.40
9. 29
0. 53
0.29
0. 24
0. 18
0. 79
9. 1
7.6
36. 4
17
0. 18
0. 10
0.23
0. 19
16.57
0.26
0.40
0.27
0. 13
0. 14
5. 4
21.9
10
0. 23
0.24
0. 12
0. 13
42.2
6. 11
0. 59
0.65
0.90
0. 16
0.20
6. 0
0. 12
2.8
19
0. 18
0.37
30. 7
1.09
7. 40
0.73
0.24
0.09
0. 21
0. 25
1.0
3. 6
20
0.30
0.23
0. 16
0. 15
0. IS
41.6
11.99
0.61
0.00
0. 23
0. 16
4.9
24.0
35. 1
11.79
0. 59
0. 93
0.24
6. 1
AVG
0.23
0.21
0.32
0. 39
0. 40
2. IS
31.5
S.D.
0.05
0.09
0.22
0.31
50.4
0. 30
10. 95
4.97
0. 58
0. 42
29.0
0. 25
a. i
26. 4
5.56
0.36
0.32
0. 13B-42
Table B.8
Monthly Inflow Sequences of Subbasins - 3
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:      TILIKU
BASIN NO.:      5b
DRAINAGE AREA:      459              km'2
PRECIPITATION:      1198         mm/yr AVG RUNOFF:      393          mm/yr
RUNOFF COEFF:      32.2         7.
I
A
S
0
ND
YR
42.0
4. IS
0. 34
0.20     0. 16
6. 6
41.4
9.28
0. 15
0.71     0. 15
6.0
19. 1
13.82
1.07
0. 12    0. 17
5. 1
39.2
9.73
0.47
0. 17    0. 16
4.7
70.9
4.95
0. 15
0.23     0.20
6.7
29.4
11.34
0.42
0.52     0. 15
4.6
26. 9
8.96
0.26
0.23     0. 18
5.4
27.8
14.78
0.50
0.37     0.20
4.7
12.2
10. 06
1.22
0. 17    0. 16
o.5
24.8
7.76
0. 36
0.51     0.20
2.9
1 10.6
12.07
0.37
0.70     0.20
10.9
39.4
9. 19
0.37
0. 17    0. 19
5.0
29.8
1.78
1.02
0. 1 1   0. 16
5.2
28.2
9.74
0. 38
0. 09    0. 16
4.5
61.2
6.02
0.95
0.23     0. 18
8.2
18.9
2.41
0. 10
0. 18    0. 13
3.6
27.2
8.97
1. 13
0.09     0. 15
3.6
43. 3
9.24
0.26
0. 19    0. 12
4.8
82.3
14. 45
0.55
0.23     0. 14
9.8
26.3
4.76
0.26
0.23     0. 19
5. 6
40.0
8.67
0.52
0.27     0. 17
5.6
24.2
3.74
0.35
0. 19    0.02B-43
Table B.8
Monthly Inflow Sequences of Subbasins - 4
GENERATED MONTHLY DISCHARGES (m 3/S)
x
BASIN NAME:       JIDA
BASIN NO.:      6c
DRAINAGE AREA:      749           kmz’ 2
PRECIPITATION:       1103        mm/yr
AVG RUNOFF:      342           mm/yr
RUNOFF COEFF:      31. 1        7.
DISCHARGE (m'3/S>
YEAR       J          F          M          A
M          J             J              A             s         □      N          D          YR
11
1        0.25  0.22     0.29      1.07     0.77     0. 16          26.6        96.7    20.45          0.73   0.83      0.27         12.4
2        0.24  0.23     0.25      1.05     0.92     0.28           21.0        11.8       4.52          0.56  0.31      0.22           3.4
3       0. 19  0.20     0.22     0.27     0.33     0. 12        111.5        41.8     19.68          0.68  0.24      0. 16        14.6
4        0.27  0.2S     0. 19    0.22     0.32     0.05             1.7        17.3       5.90          0.03   0.69      0.25           2.3
5       0. 14   0. 16    0.33     0.33     0.31     0. 18          28.7        54.6       8.05          0.29   0.61      0.25           7.8
6        0.20  0.20     0.27     0.23     0. 17    0.33           23.2        62.8       7.39         0. 50  0.99      0.31         8. 1
7        0.34   0. 35    0.30     0.23     0.24      0. 16          31.9      127.9    18. 15         1.34   0.77      0.29         15.2
8        0.29  0.29     0. 12    0. 16    0.20     8. 15          25.8       35. 1     14. 48          1.24  0.99      0.23           7.3
9       0. 19  0. 18    0.30     0.34     0.3018.14               78.5       3a. 6     19.63          1.26   0. 12     0.20        13. 0
10 0.30 0.33 0.90 0.45 0.4612.97 51.3 50. 1 12.27 0. 35 0. 13 0. 12 10.8
0.22
0. 16
0.29
0. 19
0. 18
0.25
21.9
63.9
0.01
0. 11
2.86
12
0.22
0.08
0.00
0. 46   0.26      0.25
0.24
7.6
36. 1
74. 1
13
0.24
0.26
0.44
0.27
11.21
0.34
0.72   0. 12     0.23
0. 24
10.3
6.7
52.4
4.97
14
0. 19
0. 13
0.33
0.25
0. 14
0.44   0. 13     0.24
0.45
5. 6
83.0
42.6
15
0.25
0.24
0.23
0. 45
7.26
1.20
0.26   0. 17     0.25
0.43
11.2
23.3
55. 1
8.29
16
0.27
0.21
0.90
0.40
0. 28
0. 18
0.53   0.24      0.78
7.6
9. 1
36. 4
17
0. 18
0. 10
0.23
0. 19
16.57
0.26
0. 13
0. 40   0.27      0. 14
5. 4
21.9
0.23
42.2
6. 11
IB
0.24
0. 12
0. 13
0.65
0.90
0.59   0. 16     0.20
6. 0
2.8
30.7
19
0. 18
0. 12
0.37
1.00
7. 40
0.73
0.24
0.08  0.21      0.25
3. 6
1.0
41.6
20
0.30
0.23
0. 16
0. 15
11.93
0. IB
0.00
0.61   0.23      0. 16
4.9
24.0
35. 1
11.79
0. 59   0.93      0.24
6. 1
AVG
0.23
0.21
0.32
0. 38
0. 40
2. 18
31.5
50. 4
S.D.
0.05
0.08
0.22
0.31
10. 95
0. 30
4. 97
29.0
0. 58   0. 42     0. 25
8. 1
26. 4
5.56
0. 36   0.32      0. 13B-44
Table B.8
Monthly Inflow Sequences of Subbasins - 5
GENERATED MONTHLY DISCHARGES (m''3/S)
BASIN NAME:      GOMORO
BASIN NO.:      8a
DRAINAGE AREA:      225              km'2
PRECIPITATION:
1092
mrn/yr
AVG RUNOFF:
337
irim/yr
RUNOFF COEFF:
30.9
7.
DISCHARGE ((TT3/S)
YEAR
J
F
M
A
M
J 
J 
A
s
0
N
D
YR
1
0.04
0.02
0.09
0. 11
0. 12
0.26
13.2
10.8
4.76
0.21
0.29
0.08
2.5
2
0.04
0.02
0.03
0.03
0.03
0.04
11.0
7.0
3.49
0. 12
0.29
0.08
i.a
3
0.07
0.07
0.53
0. 15
0.06
0.05
5.6
6.4
3.60
0.25
0.05
0.04
1.4
4
0. 09
0.08
0.04
0. 16
0.09
0.07
2.4
20.3
1.74
0.33
0.07
0.07
2. 1
5
0.09
0.09
0.09
0.24
0.36
4.22
22.0
17.5
3.65
0. 17
0.25
0.05
4. 1
6
0. 09
0.06
o.oa
0. 17
0. 14
2.24
10.8
8.6
3.56
0.34
0.22
0. 18
2.2
7
0.08
0.08
0.27
0. 12
0.06
0.07
18. 1
10.8
4.71
0. 14
0.06
0.04
2.9
8
0. 04
0.04
0. 11
0.04
0.03
0.07
0.8
13.8
0.63
0.24
0.08
0.37
1.4
9
0. 10
0. 08
0.02
0.04
C.25
0.06
6.0
13.6
2.20
0.02
0.20
0.07
1.9
10
0.04
0.04
0.04
0.20
0. 17
0. 14
4.6
30. 6
4.08
0.24
0.04
0.04
3.3
11
0.09
0. 05
0. 06
o.oa
0.26
0.06
2.5
io.e
5. 03
0.27
0.08
0.06
1.6
12
0. 08
0.08
0. 05
0.04
0. 19
0.41
2.7
12.2
4.04
0. 17
0.04
0.07
1.7
13
14
0.0a
0.04
0.09
0.05
0.02
0.09
9.0
8.8
2.34
0.09
0.04
0.07
1.7
o. oa
0.06
0.27
0. 11
0. 12
0.08
9.9
10.6
3.94
0.07
0.04
0.06
2. 1
15
0. 08
0.07
0.09
0.07
0.07
0.07
0.03
0. 11
0.05
0. 16
0.01
0.04
4.6
10. 1
3.24
0. 10
0.09
0.07
1.5
1a
1.0
55.9
6.61
0.22
0.25
0.0a
5.4
17
0.07
0.07
0. 06
0.25
0. 19
0. 11
23.4
24.3
0.84
0.20
0.07
0.06
4. 1
19
0. 05
0.05
0. 27
0. 12
0. 10
0. 10
6.6
13.5
5.85
0.28
0.28
0.39
2.3
19
0. 13
0. 14
0. 12
0.32
0.21
0.03
0.4
21.2
3.92
0. 15
0.09
0.07
2.2
20
0.07
0.08
0. 11
0.05
0.07
0.04
4.9
16.6
1.42
0.05
0.04
0.04
2.0
AVG
S.D.
0. 07
0. 02
0.07
0.03
0. 12
0. 12
0. 12
o. oa
0. 13
0.09
0.41
1.02
8.0
16.2
3.48
0. 18
0. 13
0. 10
2.4
6.8
11.2
1.58
0.09
0. 10
0. 10B-45
Table B.8
Monthly Inflow Sequences of Subbasins - 6
GENERATED MONTHLY DISCHARGES (m' 3/S)
s
BASIN NAME: Robi
BASIN NO.:      9a
DRAINAGE AREA:      437            km~2
PRECIPITATION:       1030        mm/yr
AVG RUNOFF:      309           mm/yr
RUNOFF COEFF:       30.0         7.
DISCHARGE (m' 3/S)
s
YEAR
J
F
M
A
M
J 
J 
A
S
□ND
YR
1
0. 12
0.09
0. 14
0.11
0. 17
0.08
11.9
24. 1
6. 49
0.80   0.00      0. 10
3.7
2
0.11
0. 16
0. 15
0.06
0.09
0.20
2.2
77.4
9.04
0.52   0.09      0.00
7.5
3
0. 10
0.08
1.20
0.35
0.20
0.05
12.9
18.9
8.77
0.70   0. 14     0. 12
3.6
4
0.09
0.06
0.07
0.09
0. 16
0.09
20. 1
28.2
5. 14
0. 15   0. 11     0.06
5
0. 13
0. 16
0.09
0.07
4.5
0.09
0. 17
4.0
24.5
7.73
0.83   0.47      0. 16
6
0.00
0.05
0. 10
0.52
3.2
0.39
0.99
26.9
15.7
7.46
7
0.82  0. 11     0. 13
0. 12
0.09
0. 15
0.07
0.00
5. 1
0.06
30.6
10.3
3.28
0
0. 13
0. 10
0. 16
0.09
0. 11   0. 11     0.07
0.00
3.0
0.08
10.4
12.0
9
5.80
0.11
0.00
0. 13
0.52
0. 17   0.09      0.24
0.38
8.99
2.5
36.2
38.0
10
0. 16
0. 14
0 ■ Oo
0.48
6.42
0.34
0. 19   0. 13     0. 10
7.6
0.06
4.0
0.00
29.0
5.71
11
0.05
0. 16
0. 12
0.09
0.20  0. 40     0.09
3.4
6.38
35. 0
20.6
5. 10
12
0. 12
0.08
0. 44
0.23
0.00
0.27  0.49      0. 14
0. 12
5. 7
0.9
0. 10
16.4
13
0. 10
0. 11
0.52
3.81
0.37
0.30   0. 11     0. 16
0.34
1.9
50. 1
14
0. 10
0.55
0.51
25.5
0. 15
6.07
0.25
0.07
0. 17   0.09      0. 13
7.0
10.6
55.7
1.54
15
0. 13
0. 14
1.21
0.70
0.50
0.44   0.47      0.09
8.99
5. 9
25. 2
16
0. 17
0. 17
0.00
0.06
18.4
2.68
0. 10
0. 18   0. 12     0. 13
0. 10
4.9
4.2
36. 4
4. 07
17
0.00
0.09
0.06
0. 11
0. 13
0.05   0. 11     0. 10
0.05
3. 0
11.0
11.1
18
0. 14
0. 12
0. 1 1
0. 18
8.20
0.24
0. 13  0. 13     0.09
0.06
1.7
2.6
22.4
19
0. 11
0.33
0.09
0. 16
0. 17
4.26
0.09
0.20   0. 10     0.20
15.9
2. 5
21.7
20
0. 14
0. 05
0. 14
0. 12
4.04
0.23
0. j6
0. 66   0. 1 1    0. 11
16.0
3.6
19. 1
1.30
0.03   0.41      0. 10
3.2
AVG
0. 12
0. 13
0.26
0.24
0.20
1.77
16.5
S.D.
0.03
0. 12
0.35
26.3
0.21
5. 35
0. 13
3.41
0. 35   0.20      0. 12
4.3
13.6
16.0
2.25
0.27   0. 16     0.04B-44
12
Table B.8
Monthly Inflow
Sequences of Subbasins - 5
GENERATED MONTHLY DISCHARGES (m''3/S)
BASIN NAME:      GOMORO
BASIN NO.:      8a
DRAINAGE AREA:      225             km^2
PRECIPITATION:
1092
mni/yr
AVG RUNOFF:
337
ffim/yr
RUNOFF COEFF:
30.9
7.
DISCHARGE (m<3/S)
YEAR
J
F
M
A
M
J
J
A
S
0
N
YR
1
0.04
0.02
0.08
0.11
0. 12
0.26
13.2
10.8
4.76
0.21
0.29     0.08
2.5
2
0.04
0.02
0.03
0.03
0.03
0.04
11.0
7.0
3.49
0. 12
0.29     0.08
1.8
3
0.07
0.07
0.53
0. 15
0.06
0.05
5.6
6.4
3.60
0.25
0.05     0.04
1.4
4
0. 08
0.08
0.04
0. 16
0.09
0.07
2.4
20.3
1.74
0.33
0.07     0.07
2. 1
5
0.09
0.09
0.09
0.24
0.36
4.22
22.0
17.5
3.65
0.17
0.25     0.05
4. 1
6
0.08
0.06
0.08
0. 17
0. 14
2.24
10.8
8.6
3.56
0.34
0.22     0. 18
2.2
7
0.08
0.08
0.27
0. 12
0.06
0.07
18. 1
10.8
4.71
0. 14
0.06     0.04
2.9
0
0.04
0.04
0. 11
0.04
0.03
0.07
0.8
13.8
0.63
0.24
0.08     0.37
1.4
9
0. 10
0.08
0.02
0.04
C.25
0.06
6.0
13.6
2.20
0.02
0.20     0.07
1.9
10
0.04
0.04
0.04
0.20
0. 17
0. 14
4.6
30.6
4.08
0.24
0.04     0.04
3. 3
11
0.09
0.05
0.06
0.08
0.26
0.06
2.5
10.8
5.03
0.27
0.08     0. 06
1.6
12
0. 08
0.08
0.05
0.04
0. 19
0.41
2.7
12.2
4.04
0. 17
0.04     0.07
1.7
13
0. 06
0.04
0.08
0.05
0.02
0.09
9.0
8.8
2.34
0.09
0.04     0.07
1.7
14
0.08
0.06
0.27
0. 11
0. 12
0.08
9.9
10.6
3.94
0.07
0.04     0.06
2. 1
15
0. 08
0.09
0.07
0.03
0.05
0.01
4.6
10. 1
3.24
0. 10
0.09     0.07
1.5
16
17
0.07
0.07
0.07
0. 07
0.07
0.06
0. 11
0.25
0. 16
0. 19
0.04
0. 11
1.0
55.9
6.61
0.22
0.25     0.06
5.4
23.4
6. 6
24.3
0.84
0.20
0.07     0.06
4. 1
18
0. 05
0. 05
0.27
0. 12
0. 10
0. 10
13.5
5.85
0.28
0.28     0.39
2.3
19
20
0. 13
0. 07
0. 14
0.08
0. 12
0. 11
0.32
0.05
0.21
0. 07
0.03
0.04
0.4
21.2
3.92
0. 15
0.09     0.07
2.2
4.9
16.6
1.42
0.05
0.04     0.04
2.0
AVG
S.D.
0.07
0. 07
0. 12
0. 12
0. 13
0.41
8.0
16.2
3.48
0.18
0. 13    0. 10
2.4
0.02
0.03
0. 12
0.08
0.09
1.02
6.8
11.2
1.58
0.09
0. 10    0. 10
1 1 ia i
iB-45
Table B.8
Monthly Inflow Sequences of Subbasins - 6
GENERATED MONTHLY DISCHARGES (m'"3/S)
BASIN NAME:         Robi
BASIN NO.:        9a
DRAINAGE AREA: 437 kmzX2
PRECIPITATION:        1030          mm/yr AVG RUNOFF:        309             mm/yr
RUNOFF COEFF:         30.0           7.
DISCHARGE (m'3/S)
YEAR
J
F
M
A
M
J
J
A
S
0
N
D
YR
1
0. 12
0.09
0.14
0.11
0. 17
0.08
11.9
24. 1
6.49
0.80
0.08
0. 10
3.7
2
0. 11
0. 16
0. 15
0.06
0.09
0.20
2.2
77.4
9.04
0.52
0.09
0.08
7.5
3
0. 10
0.08
1.20
0.35
0.20
0.05
12.9
18.9
8.77
0.70
0. 14
0. 12
3.6
4
0.09
0.06
0.07
0.09
0. 16
0.09
20. 1
28.2
5. 14
0. 15
0. 11
0.06
4.5
5
0. 13
0. 16
0.09
0.07
0.09
0. 17
4.0
24.5
7.73
0 ■ 8o
0. 47
0. 16
3.2
6
0.08
0.05
0. 10
0.52
0.39
8.99
26.9
15.7
7.46
0.82
0. 11
0. 13
5. 1
7
0. 12
0.09
0. 15
0.07
0.08
0.06
30.6
10.3
3.28
0.11
0. 11
0.07
3.8
8
0. 13
0. 10
0. 16
0.09
0.08
0.08
10.4
12.8
5.80
0. 17
0.09
0.24
2.5
9
0. 11
0.08
0. 13
0.52
0.38
8. 99
36.2
38.0
6.42
0. 19
0. 13
0. 10
7.6
10
0. 16
0. 14
0.03
0.48
0. 34
0.06
4.0
29.0
5.71
0.20
0. 48
0.09
3.4
11
0.08
0.05
0. 16
0. 12
0.09
6.38
35.0
20.6
5. 10
0.27
0.49
0. 14
5.7
12
0. 12
0.08
0. 44
0.23
0.00
0. 12
0.9
16.4
3. 81
0.30
0. 1 1
0. 16
1.9
13
0. 10
0. 11
0. 10
0.52
0.37
0.34
50. 1
25.5
6.07
0. 17
0.09
0. 13
14
0. 10
0.55
0.51
0. 15
7.0
0.25
0.07
10.6
55. 7
1.54
0.44
0. 47
0. 09
5. 9
15
0. 13
0. 14
1.21
0.78
0.50
8.99
25.2
18. 4
2. 68
0. 18
0. 12
0. 13
16
0. 17
0. 17
0.08
0.06
4. 9
0. 10
0. 10
4.2
36. 4
4.07
17
0.08
0.09
0.05
0. 11
0.06
0. 10
0. 11
0. 13
3. 8
0.05
11.0
11.1
8.20
0. 13
0. 13
18
0. 14
0. 12
0. 11
o. le
0.09
0.24
2.6
0. 06
1.7
22.4
4.26
0. 20
19
0. 11
0.33
0.09
0. 16
0. 10
0. 17
0.20
2. 5
0.09
15.9
21.7
4.04
0.66
0. 11
0. 11
20
0. 14
0.05
0. 14
0. 12
0.23
3. 6
0 • ^»6
16.0
19. 1
1.30
0.03
0. 41
0. 10
3.2
AVG
0. 12
0. 13
0.26
0.24
0.20
1.77
16.5
26.3
5.35
0.35
0.20
0. 12
S. D.
0.03
0. 12
0.35
0.21
0. 13
4.3
3.41
13.6
16.0
2.25
0.27
0. la
0.04B-46
Table B.8
Monthly Inflow Sequences of Subbasins - 7
A
GENERATED MONTHLY DISCHARGES (m 3/S)
BASIN NAME:       WESERBI BASIN NO.:        2a
DRAINAGE AREA:         168               km-v2 PRECIPITATION:         1288            mm/yr
AVG RUNOFF:         432              mm/yr RUNOFF COEFF;         33.6           7.
DISCHARGE (m''3/S)
YEAR
J
F
M
A
M
J
J
A
s
0
N
D
YR
1
0 • 05
0.05
0.05
0.03
0.03
0.23
1.6
5.4
3.49
0. 10
0.07
0.06
0.9
2
0.07
0.05
0.08
0. 10
0. 11
0.20
2.5
18.2
5.48
0.27
0.05
0.07
2.3
3
0.08
0.08
0.06
0. 17
0.21
0.05
4.2
10.0
3. 76
0. 11
0.06
0.07
1.6
4
0.08
0. 10
0.08
0.05
0.00
0.05
8.4
6.9
4. 13
0. 19
0.08
0.07
1.7
5
0.08
0.08
0.01
0.05
0.04
0.04
10. 1
20.3
1.58
0.06
0.03
0.05
2.7
6
0.05
0.03
0.24
0. 14
0.28
0.23
9.2
5.4
4.30
0.23
0.23
0.07
1.7
7
0.05
0.04
0. 10
0.06
0.06
0.05
2.3
11.2
2. 18
0. 14
0.26
0.08
1.4
8
0. 08
0. 10
0. 11
0.07
0. 10
0.05
0.4
50.6
3.46
0. 18
0.05
0.04
4.6
9
0.05
0.02
0. 16
0.09
0.08
0.05
10.0
10.0
1.05
0.08
0.05
0.06
1.8
10
0.08
0.08
0. 10
0.09
0.08
0.06
30.0
16.8
1.53
0. 10
0.07
0.07
4. 1
11
0.08
0.06
0.05
0.09
0.05
0.24
9.3
4.2
2.97
0. 16
0.04
0.05
1.4
12
0. 06
0.06
0.06
0.05
0.07
0.05
2.2
11.9
1.73
0.30
0.26
0.07
1.4
13
0. 05
0.03
0.01
0.07
0.06
0. 18
4.7
6.5
5.20
0.39
0.06
0.03
1.4
14
0.06
0.06
0.05
0.07
0. 03
0. 10
1.9
11.0
0.79
0.03
0.06
0.06
1.2
15
0. 04
0.09
0. 15
0.07
0.00
0.05
2. 1
50.7
6.32
0. 13
0. 15
0.07
5.0
16
0. 08
0. 08
0.04
0. 10
0.31
0.23
12.8
6.6
0.43
0.28
0.05
0.03
1.7
17
0. 07
0. 07
0.56
0. 16
0. 34
0.07
0.4
12.0
4.47
0. 12
0.09
0.06
1.5
IB
0. 05
0.05
0.09
0.07
0.06
0.07
5.0
12.5
3.33
0. 17
0.07
0.07
1.8
19
0.04
0. 03
0.03
0.08
0.24
0.01
22.2
52.3
4.Cl
0. 18
0.09
0.04
6.6
20
0. 03
0.02
0.07
0. 15
0.22
0.05
1.9
11.0
0.08
0.09
0.07
1.3
AVG
0. 06
0.06
0. 11
0.09
0. 12
0. 10
7. 1
16. 7
3. 12
0. 16
0. 10
0.06
2.3
S. D.
0.02
0.03
0. 12
0.04
0. 11
0.08
7.6
15.5
1.65
0.09
0.07
0.01B-47
Table B.8
Monthly Inflow Sequences of Subbasins - 8
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:
DUBER
BASIN NO.:
12c
DRAINAGE AREA:
312
km''2
PRECIPITATION:
1225
mm/yr
AVG RUNOFF:
401
mm/yr
RUNOFF COEFF:
32.7
7.
J             F             M            A             M             J                 J                 A                 s         □      N             D              YR
DISCHARGE (m''3/S)
1
0. 16
0. 10
0.11
0.21
0. 19
0. 15
18. 1
24.7
7.27
0.29
0.48
0.20
4.3
2
0. 14
0. 10
0. 14
0. 12
0. 14
4.70
14.4
16.3
7. 48
0.44
0.07
0.09
3.7
3
0. 15
0. 11
0. 13
0. 10
0.38
0.09
11.1
29. 9
1.88
0. 10
0.50
0. 14
3.7
4
0. 16
0. 16
0. 10
0. 10
0. 12
1.52
20.5
30.2
8.86
0.36
0.09
0. 19
5.2
5
0. 16
0. 17
0.36
0.27
0.38
0.02
4.0
30.0
6.75
0.34
0. 12
0.09
3.6
6
0.08
0.00
0.07
0.11
0. 17
0.22
26.7
30.9
6.81
0.27
0.07
0.08
5.5
7
0. 12
0. 14
0. 16
0.36
0.31
0. 10
4.5
20.0
10.29
0.43
0.09
0. 14
3. 1
8
0.08
0.08
0.08
0. 10
0. 11
5.76
16.2
16. 4
6.53
0.33
0. 17
0. 15
3.8
9
0. 12
0. 13
0.09
0. 10
0.09
0. 06
20. 1
30.3
6.83
0. 35
0.07
0. 13
4.9
10
0. 11
0. 12
0. 11
0. 11
0.23
0.26
9.2
16.3
6.58
0- 33
0.52
0. 14
2.8
11
0. 17
0. 15
0. 16
0. 19
0. 17
0. 13
2.2
15.3
1.28
0. 14
0.30
0. 15
1.7
12
0. 16
0. 13
0. 12
0.11
0.09
0.27
14.5
44. 4
6.04
0.32
0. 51
0. 14
5. 6
13
0. 10
0. 10
0.24
0. 16
0.41
0. 03
20.6
27. 1
3. 80
0.45
0. 15
0. 10
4. 4
14
0. 12
0. 13
0.21
0.30
0.11
0.01
11.5
27.2
7. 59
0.28
0. 18
0. 14
15
0.00
0.08
0. 10
4. 0
0. 10
0. 06
0. 16
21.6
10. 5
3.83
0. 15
0. 17
16
0. 18
0- 19
0. 14
0.29
0.22
0.25
3. 1
0. 42
16. 1
25.7
1. 13
0. 06
17
0. 10
0.07
0.49
0. 14
0.30
0. 07
0.20
3. 7
0.07
12. 1
40.7
7.74
0.30
0.07
18
0. 11
0.06
0.20
0. 13
0. 1 1
0. 12
5.2
2. 29
15. 0
16.3
6. 72
0. 44
19
0. 13
0. 10
0. 16
0. 12
0. 15
0.11
0. 13
3. 5
0. 10
15.8
30. 3
5. 75
0. 17
20
0. 15
0.06
0. 49
0.29
0. 17
0. 40
0. 09
4.4
0. 17
0. 7
28. 7
9.21
0. 49
0.53
0. 15
3. 4
VS
0. 13
0. 11
0. 18
0. 18
0.20
0.83
13. 7
25.6
6. 12
.D.
0.03
0.04
0. 12
0. 30
0.09
0. 11
O. 23
0.13
4. 0
1.62
7. 0
8. 7
2.53
0. 12
0. 18
0.04B-46
Table B.8
Monthly Inflow Sequences of Subbasins - 7
GENERATED MONTHLY DISCHARGES (m~3/S)
BASIN NAME:       WESERBI BASIN NO.:        2a
DRAINAGE AREA:         168               kmzx2 PRECIPITATION:         1288            mm/yr
AVG RUNOFF:         432              mm/yr RUNOFF COEFF:          33.6           7.
DISCHARGE (m~3/S)
YEAR
J
F
M
A
M
J
J
A
s
0
N
D
YR
1
0.05
0.03
0.05
0.03
0.03
0.23
1.6
5.4
3.49
0. 10
0.07
0.06
0.9
2
0.07
0.05
0.08
0. 10
0. 11
0.20
2.5
18.2
5.48
0.27
0.05
0.07
2.3
3
0.08
0.08
0.06
0. 17
0.21
0.05
4.2
10.0
3.76
0. 11
0.06
0.07
1.6
4
0. 08
0. 10
0.08
0.05
0.00
0.05
8.4
6.9
4. 13
0. 19
0.08
0.07
1.7
5
0.08
0.08
0.01
0.05
0.04
0.04
10. 1
20. 3
1.58
0.06
0.03
0.05
2.7
6
0. 05
0.03
0. 24
0. 14
0.28
0.23
9.2
5.4
4.30
0.23
0.23
0.07
1.7
7
0.05
0.04
0. 10
0.06
0.06
0.05
2.3
11.2
2. 18
0. 14
0.26
0.08
1.4
8
0. 08
0. 10
0. 11
0.07
0. 10
0. 05
0.4
50.6
3.46
0. 18
0.05
0.04
4.6
9
0.05
0.02
0. 16
0.09
0.08
0.05
10.0
10.0
1.05
0.08
0.05
0.06
1.8
10
0.08
0.08
0. 10
0.09
0.08
0.06
30.0
16.8
1.53
0. 10
0.07
0.07
4. 1
11
0.08
0.06
0.05
0.09
0.05
0.24
9.3
4.2
2.97
0. 16
0.04
0.05
1.4
12
0.06
0.06
0.06
0. 05
0.07
0.05
2.2
11.9
1.73
0.30
0.26
0.07
1.4
13
0.05
0. 03
0.01
0.07
0.06
0. 18
4.7
6.5
5.20
0.39
0.06
0.03
1.4
14
0.06
0.06
0.05
0.07
0 ■ Oo
0. 10
1.9
11.0
0.79
0.03
0.06
0.06
1.2
15
0. 04
0.09
0. 15
0.07
0.00
0.05
2. 1
50.7
6.32
0. 13
0. 15
0.07
5.0
16
0.08
0.08
0.04
0. 10
0.31
0.23
12.8
6.6
0.43
0.28
0.05
0.03
1.7
17
0.07
0.07
0.56
0. 16
0.34
0.07
0.4
12.0
4.47
0. 12
0.09
0.06
1.5
T TT
18
0.05
0.05
0.09
0.07
0.06
0.07
5.0
12.5
0. 17
0.07
0.07
1.8
19
0. 04
0.03
0. 03
0. 08
0.24
0.01
22.2
52.3
4.Cl
0. 18
0.09
0.04
6.6
20
0.03
0.02
0.07
0. 15
0.22
0.05
1.9
11.0
2. 13
0.08
0.09
0.07
1.3
iVG
0. 06
0.06
0. 11
0.09
0. 12
0. 10
7. 1
16.7
3. 12
0. 16
0. 10
0. 06
2.3
i.D.
0.02
0.03
0. 12
0.04
0. 11
0.08
7.6
15.5
1.65
0.09
0.07
0.01B-47
Table B.8
Monthly Inflow Sequences of Subbasins - 8
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:
DUBER
BASIN NO.:
12 c
DRAINAGE AREA:
312
km~2
PRECIPITATION:
1225
mm/yr
AVG RUNOFF:
401
mm/yr
RUNOFF COEFF:
32.7
7.
DISCHARGE (m~3/S)
YEAR           J             F           M          A            M         J                J                A                s          0             N             D             YR
1
0. 16
0. 10
0. 11
0.21
0. 19       0. 15
18. 1
24.7
7.27
0.29
0.48
0.20
4.3
2
0. 14
0. 10
0. 14
0. 12
0. 14       4.70
14.4
16.3
7.48
0.44
0.07
0.09
3.7
3
0. 15
0. 11
0. 13
0. 10
0.38        0.09
11.1
29.9
1.88
0. 10
0.50
0. 14
3.7
4
0. 16
0. 16
0. 10
0. 10
0. 12       1.52
20.5
30.2
8.86
0.36
0.09
0. 19
5.2
5
0. 16
0. 17
0.36
0.27
0.38        0.02
4.0
30.0
6.75
0.34
0. 12
0.09
3.6
6
0.08
0.00
0.07
0. 11
0. 17
0.22
26.7
30.9
6.81
0.27
0.07
0.08
5.5
7
0. 12
0. 14
0. 16
0.36
0.31
0. 10
4.5
20.0
10.29
0.43
0.09
0. 14
3. 1
8
0.08
0.08
0.08
0. 10
0. 11
5.76
16.2
16.4
6.53
0.33
0. 17
0. 15
3.8
9
0. 12
0. 13
0.09
0. 10
0.09
0.06
20.1
30.3
6 • 8s_<
0.35
0.07
0. 13
4.9
10
0. 11
0. 12
0. 11
0. 11
0.23
0.26
9.2
16.3
6.58
0.33
0.52
0. 14
2.8
11
0. 17
0. 15
0. 16
0. 19
0. 17
0. 13
r*
«k ■ 4k
15.3
1.28
0. 14
0.30
0. 15
1.7
12
0. 16
0. 13
0. 12
0.11
0.09
0.27
14.5
44. 4
6.04
0.32
0.51
0. 14
5.6
13
0. 10
0. 10
0.24
0. 16
0.41
0.03
20.6
27. 1
3. 80
0.45
0. 15
0. 10
4. 4
14
0. 12
0. 13
0.21
0.30
0. 11
0.01
11.5
27.2
7.59
0.28
0. 18
0. 14
4.0
15
0.08
0.08
0. 10
0. 10
0.06
0. 16
21.6
10.5
3.83
0. 15
0. 17
0.22
3. 1
16
0. 18
0. 19
0. 14
0.29
0.25
0.42
16. 1
25.7
1. 13
0. 06
0. 14
0.07
3. 7
17
0. 10
0.07
0.49
0.30
0.20
0.07
12. 1
40.7
7.74
0.30
0.07
0. 11
5.2
is
0. 11
0.06
0.20
0. 13
0. 12
2.29
15.0
16.3
6.72
0. 44
0. 15
0. 11
19
0. 13
0. 10
0. 16
0. 12
3.5
0. 13
0. 10
15.8
30.3
5.75
0. 17
0. 17
0.09
4.4
20
0. 15
0.06
0. 49
0.29
0. 40
0. 17
0. 7
28.7
9.21
0.49
0.53
0. 15
3. 4
AVG           0. 13   0. 1 1      0. 18       0. 18       0.20        0.83             13. 7             25.6        6. 12            0. 30   0.23        0.13               4.0 S.D.            0.03   0.04        0. 12       0.09        0. 11        1.62              7.0                8. 7         2.53             0. 12   0. IS        0.04in i> i
•      < I I ] f- H H H H H H »■*
Q O I QO(0\|0‘UI^UK)hO’0(0>|0‘UI*WNh
B-48
Table B.8
Monthly Inflow Sequences of Subbasins - 9
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:
CHACHA
BASIN NO. :
14a
DRAINAGE AREA:
590
km' 2
x
PRECIPITATION:
1076
mm/yr
AVG RUNOFF:
330
mm/yr
RUNOFF COEFF:
30.7
7.
DISCHARGE (m' 3/S)
x
YEAR J F M A
M
J
J
A
S
0
N
D
YR
0.22
0. 15
0. 19
0.34
0.38
0.08
0.86
0. 12
17.8
22.7
17.34
0.84
0.20
0. 12
5.   1
0. 17
0. 1 1
0. 16
0.29
0.38
34.8
39.0
10.76
0.51
0.81
0.24
0. 19
0. 19
0. 12
0.21
0 • oO
24.4
49. 1
2.31
0.49
0.89
0.25
7.3
6.5
0.
15   0.09
0.
15   0.62
0.39
0.21
6.9
41.5
1.91
0.34
0. 11
0. 13
0.24
0.24
0.06
0.31
0.33
0.22
0.29
0.77
50. 1
76.0
2.5S
0. 12
0.28
0. 13
4.4
10.9
0. 19
3. 1
0. 17
0. 11
0.21
0.B3
0. 12
0. 15
0. 10
3.0
26.7
5. 14
0.56
0. 15
0.33
0.36
0.36
39.9
55.2
4.01
0. 17
0.89
0.24
0.22
0.22
0. 17
0.09
0. 16
0. 19
0.27
7.3
41.0
2.21
0.43
0.20
0.21
0.
44   0.22
0. 13
0.51
3.5
27. 1
5. 19
0.07
0.89
0.2S
8.6
4.4
3.3
0. 26
1.04
1.09
0.26
0.22
0.37
0.64
0. 41
0.22
30.4
42.2
18.90
0.63
0. 16
0.20
0.25
0.21
0.22
0.34
0. 18
0.21
0.24
6.5
64.2
6.53
0.45
0. 11
0. 19
0.34
0.26
0.27
0. 11
19. 1
46.6
19.07
0.73
0. 14
0. 19
8.0
6.6
7.3
0. 17
0. 13
0.32
0.32
0. 15
25.2
30.7
12.76
0.71
o.e7
0.25
6.  0
0. 19       0. 12       0. 11       0.09
0. 22       0. 17       0.20
0.52
0. 35 0. 1 1 33. e 49.5 12. 19 0. 47 0.89 0.27
0.71 0. 11 6.9 47.5 5.37 0. 15 0. 16 0.22
8.2
5.2
0. 18
0.20
0.26
0.    13
0.
19   0.20
0.59
21.8
34.0
7.92
0. 48
0. 10
0. 14
5.5
0.26
0 • 8^,
0.
47   0.39
0.77
15.8
■3
16.50
0.74
0.24
0.20
5. a
0. 19
0. 12
0.33
0.27
0.70
0. 48
o.es
15.3
44. 2
11.00
0.64
0.20
0. 22
0. 21
0. 15
0. 33
0. 11
34.0
28.2
16.02
0.44
0. 12
0.21
6.2
6.7
0.24
0.07
0.25
0. 11       0. 13       1.82              9. 1            31.7      14.33            0.63   0.27       0. 19
0.21         0.25         0.29         0-31         0.33         0.40      20.3          41.5          9.60          0.48          0.38          0.20
4.9
6. 2
0.03 0.29 0.21 0.19 0.18 0.41
13.5 13.4 6.00 0.22 0.33 0.05B-49
Table B.8
Monthly Inflow
Sequences of Subbasins - 10
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:       JINJER
BASIN NO.;        10a
DRAINAGE AREA:        238                kmz'2 PRECIPITATION:        1OOO          mm/yr
AVG RUNOFF:        295              mm/yr RUNOFF COEFF:         29.5           7.
DISCHARGE (m^3/S)
YEAR
J
F
M
A
M
J
J
A
s
0
N
D
YR
1
0.06
0.04
0.08
0. 10
0. 10
0.00
4.9
14.4
0.62
0.07
0. 15
0.06
1.7
A.
0.04
0.29
0.28
0.34
0.46
0.05
4.4
12.8
4.97
0. 14
0.05
0.07
2.0
3
0.07
0.05
0.06
0.06
0.00
0. 13
29.2
11.8
3 • -^/O
0. 07
0. 07
0.06
3.7
4
o.os
0. 10
0.09
0. 11
o.oe
0.09
0. 4
18.3
3.21
0. 10
0.05
0. ^5
1.9
5
0.08
0.06
0. 13
0.24
0. 19
0.24
6.9
8. 1
3.23
0.35
0.26
0.05
1.7
6
0.06
0.02
0.06
0.06
0.30
0.07
0.5
11.2
3.33
0. 10
0.03
0.34
1.3
7
0. 12
0.37
0.29
0. 10
0.08
0. 18
0. 6
19.0
4.57
0. 18
0.05
0.07
2. 1
8
0.07
0.32
0.07
0. 11
0.32
0.24
21.4
11.8
4.23
0. 16
0.06
0.02
3. 2
9
0.09
0.03
0.06
0.03
0.02
0.07
5.0
15.2
4.33
0. 19
0.26
0. 06
2. 1
10
0.09
0. 19
0.26
0.09
0.09
0.05
28. 7
17. 4
0. 60
0.04
0.05
0.27
4.0
11
0.08
0.02
0.25
0. 11
0.00
0.05
23. 1
9.S
5.05
0.25
0.23
0.05
3.2
12
0.06
0.32
0. 10
0.07
0.30
0.03
8.9
15.3
3.32
0.05
o.oe
0.04
2. 4
13
0.05
0.00
0.09
0.08
0. 10
0.20
1.7
24. 1
1.72
0.39
0.05
0.02
2.4
14
0.09
0.07
0.04
0.03
0. 06
0.03
26.0
14.7
1.54
0. 09
0.23
0.08
3. 6
13
0.08
0.06
0.04
0.23
0. 14
0. 05
1. 1
4.6
0. 17
0 • 05
0.05
0.8
16
0.04
0.05
0.03
0.03
0. 17
0.04
0.5
11.5
4.95
0.24
0. 22
0. 34
1.5
17
0. 12
0. 11
0.02
0.07
0.00
0.08
1.5
20.5
5.08
0. 14
0.24
0.36
2. 4
18
0.09
0.03
0.08
0.06
0.03
0.24
1.5
3.9
1 • 5*^
0. 16
0. 26
0.05
0. 7
19
0.04
0. 03
0.05
0.07
0.03
0. 11
10.0
S.S
3.57
0. 42
0.04
0.03
1.9
20
0.03
0.02
0.08
0.07
0.04
0. IB
8.3
9.6
4.62
0.44
0.06
0.26
2.0
AVG 0.07 0. 11 0. 11 0. 10 0.13 0. 11 9. 3 13. 1 7 0. 19 0. 13 0. 13
S.D. 0.02 0. 12 0.09 0.08 0. 13 0.08 10.3 5. 1 1.46 0. 12 0.09 0. 13B-50
—-s purpose, evaporation data contained in the 1973 Nations development Program (UNDP) technical report on 
"Investigation of Geothermal Resources for Power Development"
•ere analyzed. In this report, mean annual evaporation and evapotranspiration rates at various topographic elevations in Ethiopia are presented. From these data, the evaporation rate for reservoirs on the plateau (at an elevation of about
2,600 m) was calculated to be about 1,100 mm/yr. With a corresponding natural evapotranspiration of about 675 mm/yr, the net reservoir losses are estimated to be about
425 mm/yr.
To determine the effect of these losses on tne available mean annual power flow, the reservoir surface area at an average operating reservoir level of 2,590 m was determined for each subbasin. The losses were then calculated as a percentage of tne runoff of each subbasin.
The results of these calculations are shown in Table B.9.
It can be seen from this table that the average loss over the subbasins of the reconnaissance study amounts to 3.4%. For the main base schemes alone (i.e., Tiliku Aleltu, Jida, Gomoro and Robi), the loss is 3.9%.
The average operating surface area of the Robi reservoir is very small. This is because the surveyed riverbed level at the Robi dam is at about elevation 2,288 m, resulting in a mean reservoir depth of about 2 m. Typically, the Robi reservoir will operate during the wet season to regulate inflows and to provide the power flow during the early part of the dry season. The reservoir will then be empty during the remainder of the dry season.B-51
TABLE B.9
RESERVOIR EVAPORATION LOSSES
Drainage
Reservoir
Area at
Evaporation
Loss as
 Percent
Site            Subbasin
Area
el 2,590
Of Run
off
2
(km  )
2
(km  )
3a              Agat
92
8.0
8.6
4b             Tinishu Aleltu
37
0.5
1.4
5b             Tiliku Aleltu
458
4.0
1.0 )
) Base schemes
6c              Jida
749
36.0
6.0 
) average
) evaporation
8a              Gomoro
225
16.0
9.0 
) equals 3.9%
)
9a              Robi
437
3.0
1.0 )
2a              Weserbi
168
10.0
5.8
12c            Duber
312
1.5
0.5
14a            Chacha
590
112.0
2.7
10a            Jinjer
238
7.0
3.7
Basin Average Evaporation
3.4B-50
For this purpose, evaporation data contained in the 1973 United Nations Development Program (UNDP) technical report on "Investigation of Geothermal Resources for Power Development" were analyzed. In this report, mean annual evaporation and evapotranspiration rates at various topographic elevations in Ethiopia are presented. From these data, the evaporation 
rate for reservoirs on the plateau (at an elevation of about
2,600 m) was calculated to be about 1,100 mm/yr. With a corresponding natural evapotranspiration of about 675 mm/yr, the net reservoir losses are estimated to be about
425 mm/yr.
To determine the effect of these losses on the available mean annual power flow, the reservoir surface area at an average operating reservoir level of 2,590 m was determined for each subbasin. The losses were then calculated as a percentage of the runoff of each subbasin.
The results of these calculations are shown in Table B.9.
It can be seen from this table that the average loss over the subbasins of tne reconnaissance study amounts to 3.4%. For the main base schemes alone (i.e., Tiliku Aleltu, Jida, Gomoro and Robi), the loss is 3.9%.
The average operating surface area of the Robi reservoir is very small. This is because the surveyed riverbed level at the Robi dam is at about elevation 2,288 m, resulting in a mean reservoir depth of about 2 m. Typically, the Robi reservoir will operate during the wet season to regulate inflows and to provide the power flow during the early part of tne dry season. The reservoir will then be empty during the remainder of tne dry season.B-51
TABLE B.9
RESERVOIR EVAPORATION LOSSES
Reservoir
Area at
Evaporation
Drainage
Area
Loss
 as Per
cent
Site            Subbasin
el 2,590
Of R
unoff
2
(km  )
2
(km )
3a              Agat
92
8.0
8.6
4b              Tinishu Aleltu
37
0.5
1.4
5b             Tiliku Aleltu
458
4.0
1.0
)
)
Base schemes
6c              Jida
749
36.0
6.0
)
average
)
evaporation
8a              Gomoro
225
16.0
9.0
)
)
)
equals 3.9%
9a              Robi
437
3.0
1.0
2a              Weserbi
168
10.0
5.8
12c            Duber
312
1.5
0.5
14a            Chacha
590
112.0
2.7
10a            Jinjer
238
7.0
3.7
Basin Average Evaporation
3.4B-52
For the Duber scheme, the alternative development of a small dam in the Tiliku Duber River was considered. The resulting reservoir will only provide for weekly regulation of peak inflows during the wet season and evaporation loss will be small.
The Weserbi scheme is the only Aleltu scheme which originally contained large natural swampy areas which would be flooded out by the proposed reservoir. This swamp was not considered to be seasonal and the original swamp area was subtracted from the reservoir area to determine the incremental area
from which evaporation losses could be calculated.
It is noted that the assumed reservoir areas are derived mostly from the large-scale 1:250 000-scale mapping. In addition, the actual average operating levels of the indivi dual reservoirs can only be estimated at this stage and will need to be realistically established in future studies. It was, therefore, decided that the average basin loss of about 3.4% would not significantly affect the accuracy of the results of the reconnaissance studies. However, for the prefeasibility level studies of the Tiliku Aleltu and Jida reservoirs, the estimated evaporation losses were taken into account.
Bo - RESERVOIR REGULATION ANALYSIS
To determine the degree of regulation at each basin develop ment, the monthly inflows of the subDasins were routed through the reservoirs using the same water balance model as that used for the preliminary reconnaissance model runsB-53
(described in Section B3). For the Tiliku Aleltu and Jida subbasins, surveyed reservoir volumes were used as part of the prefeasibility level study effort. For the remaining subbasins, estimated reservoir volumes based on surveyed riverbed levels at the damsites only were used. An example
of the reservoir regulation analyses for the Jida reservoir
is shown in Table B. 10 and a summary of the relationship between reservoir volume and degree of regulation is shown in Table B.ll.
As indicated in Section B3, the results of the preliminary analyses for 100% flow regulation are shown in Table B.ll for comparison purposes. It can be derived that a significant difference exists between the calculated reservoir live
storage requirements in the preliminary and final subbasin inflow sequences. This can be caused by the larger variation in monthly flows in the synthesized prefeasibility phase reference hydrology.
B7 - FLOOD FLOW STUDIES
B7.1 - General
To permit preliminary sizing of construction diversion and flood handling facilities of the proposed Tiliku Aleltu and Jida schemes, estimates of flood peak magnitudes and shapes of inflow hydrographs were required.
Because of the scarcity of recorded flow data available in and around the Aleltu project area, and also to improve the reliability of the calculated flood peaks, a broad-basedB-54
TABLE B.10 EXAMPLE JIDA RESERVOIR REGULATION COMPUTER RUNS
STATION: BASIN 4 -JIDA MONTHLY RUNOFF in «A3/s
JAN
FEB
MR
APR
NAY
JUN
JUL
AUS
SEP
OCT
NOV
DEC
AVS
I
2
0.3
0.2
0.2
0.2
0.3
0.3
1.1
1.1
0.8
0.9
0.2
0.3
26.6
21.0
96.7
11.8
20.5
4.5
0.7
0.6
0.8
0.3
0.3
0.2
12.4
3.4
3
4
0.2
0.3
0.2
0.3
0.2
0.2
0.3
0.2
0.3
0.3
0.1
0.1
111.5 1.7
41.B
17.3
19.7
5.9
0.7
0.0
0.2
0.7
0.2
0.3
14.6
2.3
5
6
0.1
0.2
0.2
0.2
0.3
0.3
0.3
0.2
0.3
0.2
0.2
0.3
2B.7
23.2
54.7
62.8
8.1
7.4
0.3
0.5
0.6
1.0
0.3
0.3
7.8
8.1
7
8
0.3
0.3
0.4
0.3
0.3
0.1
0.2
0.2
0.2
0.2
0.2
8.1
31.9
25.8
127.9
35.1
18.2
14.5
1.3
1.2
0.8
1.0
0.3
0.2
15.2
7.3
9
10
0.2
0.3
0.2
0.3
0.3
0.9
0.3
0.5
0.3
0.5
13.1
13.0
78.5
51.3
36.6
50.1
19.6
12.3
1.3
0.4
0.1
0.1
0.2
0.1
13.0
10.8
11
12
0.2
0.2
0.2
0.0
0.3
0.1
0.2
0.1
0.2
0.0
0.3
0.2
21.9
36.1
63.9
74.1
2.9
11.2
0.5
0.7
0.3
0.1
0.3
0.2
7.6 10.3
13
14
0.2
0.2
0.3
0.1
0.4
0.3
0.3
0.3
0.3
0.1
0.2
0.5
6.7
83.0
52.4
42.6
5.0
7.3
0.4
0.3
0.1
0.2
0.2
0.3
5.6 11.2
15
16
0.3
0.3
0.2
0.2
0.2
0.9
0.5
0.4
1.2
0.3
0.4
0.2
23.3
9.1
55.1
36.4
8.3
16.6
0.5
0.4
0.2
0.3
0.9
0.1
7.6
5.4
17
16
0.2
0.2
0.1
0.2
0.2
0.1
0.2
0.1
0.3
0.7
0.1
0.9
21.9
2.8
42.2
30.7
6.1
7.4
0.6
0.1
0.2
0.2
0.2
0.3
6.0
3.6
19
20
0.2
0.3
0.1
0.2
0.4
0.2
1.1
0.2
0.7
0.2
0.2
0.0
1.0
24.0
41.6
35.1
12.0
11.8
0.6
0.6
0.2
0.9
0.2
0.2
4.9
6.1
0.2
0.2
0.3
0.4
0.4
2.2
31.5
50.4
10.9
0.6
0.4
0.3
8.2
Drainage Area: 749 ka*2
Soicific Runoft; 343.6208 aaTable B.10
Example Jida Reservoir Reaulacion Computer Runs - 2
B-55
A
CUMULATIVE STORAGE (in a 3/s)
Drift Rita: 4.08 aA3/S
JAN      FEB   MAR      APR       MAY      JUN        JUL AUG             SEP       OCT       NOV       DEC    SPILL   ST0RA6E
1
-3.8
-7.7
-11.5
-14.5
-17.6
-21.7
0.8
92.6
16.4
-3.3
-6.6
-10.4
109.8
-21.7
2
-14.2
-18.1
-21.9
-24.9
-28.1
-31.9
-15.0
-7.3
-6.9
15.6
-10.4
-14.1
-18.0
-11.2
0.0
-31.9
3
-21.9
-25.8
-29.6
-33.4
-37.2
-41.1
66.2
37.8
-3.4
-7.2
119.6
-41.1
4
-15.0
-18.8
-22.6
-26.5
-30.3
-34.3
-36.6
-23.5
-21.6
4.0
3.3
14.1
10.4
15.6
8.2
-25.7
-29.1
-32.9
0.0
-36.6
5
-36.8
-40.8
-44.5
-48.3
-52.0
-55.9
-31.3
19.3
-3.8
-7.3
-11.1
23.2
-55.9
6
-15.0
-18.8
-22.6
-26.5
-30.4
-34.2
-15.0
43.7
-3.6
-6.7
-10.4
-9.8
-9.8
47.0
-34.2
7
-14.2
-17.9
-21.7
-25.5
-29.4
-33.3
-5.5
118.4
-2.7
-6.0
132.4
-33.3
8
-13.6
-17.4
-21.4
-25.3
-29.2
-25.1
-3.4
27.7
-2.8
-5.9
38.1
-29.2
9
-13.7
-17.6
-21.3
-25.1
-28.9
-14.8
59.6
32.5
-2.8
-6.8
-10.7
107.7
-28.9
10
-14.4
-18.2
-21.4
-25.0
-28.6
-19.7
27.6
46.0
-3.7
-7.7
-11.6
81.8
-28.6
11
-15.5
-19.4
-23.2
-27.1
-31.0
-34.8
-17.0
42.9
-1.2
7.1
0.9
3.2
4.2
12.5
2.0
-4.8
-8.7
-12.5
42.9
-34.8
12
-16.3
-20.4
-24.4
-28.4
-32.5
-36.3
-4.3
65.7
-3.4
-7.3
-11.2
72.9
-36.3
13
-15.0
-18.8
-22.5
-26.3
-30.0
-33.8
-31.2
17.1
-3.6
-7.6
-11.4
18.0
-33.8
14
-15.3
-19.3
-23.0
-26.8
-30.8
-34.4
44.5
38.5
-3.8
-7.7
-11.6
86.2
-34.4
15
-15.4
-19.2
-23.1
-26.7
-29.6
-33.2
-14.0
37.0
-3.5
-7.4
-10.7
41.2
-33.2
16
-14.5
-18.4
-21.5
-25.2
-29.0
-32.9
-27.8
4.5
-3.7
-7.5
-11.4
17.0
-32.9
17
-15.3
-19.3
-23.1
-27.0
-30.9
-34.8
-16.9
21.2
-3.5
-7.4
-11.3
23.2
-34.8
18
-15.1
-19.0
-22.9
-26.9
-30.3
-33.5
-34.8
-8.1
-4.8
4.1
7.7
-8.8
-12.7
-16.5
0.0
-34.8
19
-20.4
-24.4
-28.1
-31.1
-34.4
-38.3
-41.3
-3.8
-3.5
-7.3
-11.2
4.1
-41.3
20
-15.0
-18.9
-22.8
-26.7
-30.6
-34.7
-14.7
16.3
-3.5
-6.6
-10.5
24.0
-34.7
A
CUMULATIVE STORAGE (in a 3/«)
Drift Rita: 4.89 aA3/S
JAN       FEB      MAR      APR      MAY       JUN       JUL       AU6       SEP       OCT       NOV       OEC     SPILL ST0RA6E
1
-4.6
-9.3
-13.9
-17.7
-21.9
-26.6
-4.9
86.9
15.6
-4.2
-8.2
-12.9
102.5
-26.6
2
-17.5
-22.2
-26.8
-30.7
-34.6
-39.2
-23.2
-16.3
-16.7
-21.0
-25.6
-30.2
0.0
-39.2
3
-34.9
-39.6
-44.3
-48.9
-53.5
-58.3
48.3
37.0
14.8
-4.2
-8.9
-13.6
100.0
-58.3
4
-18.2
-22.8
-27.5
-32.2
-36.8
-41.6
-44.8
-32.4
-31.4
-36.3
-40.5
-45.1
0.0
-45.1
5
-49.9
-54.6
-59.2
-63.8
-68.3
-73.1
-49.2
0.5
3.2
-4.6
-8.9
-13.5
3.7
-73.1
6
-18.2
-22.9
-27.5
-32.2
-36.9
-41.5
-23.2
34.8
2.5
-4.4
-8.3
-12.9
37.2
-41.5
7
-17.4
-22.0
-26.6
-31.2
-35.9
-40.6
-13.6
109.4
13.3
-3.6
-7.7
-12.3
122.6
-40.6
8
-16.9
-21.5
-26.3
-31.0
-35.7
-32.4
-11.6
18.7
9.6
-3.7
-7.6
-12.2
28.3
-35.7
9
-16.9
-21.6
-26.2
-30.8
-35.4
-22.1
51.4
31.7
14.7
-3.6
-8.4
-13.1
97.9
-35.4
10
-17.7
-22.3
-26.3
-30.7
-35.1
-27.1
19.4
45.2
7.4
-4.5
-9.3
-14.1
72.0
-35.1
11
-18.8
-23.5
-28.1
-32.8
-37.5
-42.2
-25.1
33.9
-2.0
-6.5
-11.1
-15.7
33.9
-42.2
12
-20.4
-25.3
-30.1
-34.9
-39.8
-44.4
-13.3
55.9
6.3
-4.2
-8.9
-13.6
62.3
-44.4
13
-18.3
-22.9
-27.4
-32.0
-36.5
-41.2
-39.3
8.2
0.1
-4.5
-9.2
-13.9
8.2
-41.2
14
-18.6
-23.3
-27.9
-32.5
-37.3
-41.7
3o.3
37.7
2.4
-4.6
-9.4
-14.0
76.4
-41.7
15
-18.6
-23.3
-28.0
-32.4
-36.1
-40.6
-22.2
28.1
3.4
-4.4
-9.0
-13.1
31.5
-40.6
lo
-17.8
-22.4
-26.4
-30.9
-35.5
-40.3
-36.0
-4.5
7.2
-4.5
-9.1
-13.9
7.2
-40.3
17
-18.0
-23.4
-28.0
-32.7
-37.4
-42.1
-25.1
12.2
1.2
-4.3
-9.0
-13.7
13.4
-42.1
IB
-18.4
-23.0
-27.8
-32.6
-36.8
-40.8
-42.9
-17.1
-14.6
-19.4
-24.1
-28.7
0.0
-42.9
19
-33.5
-38.2
-42.8
-46.0
-50.7
-55.4
-59.2
-22.6
-15.5
-19.8
-24.4
-29.2
0.0
-59.2
20
-33.7
-38.4
-43.1
-47.9
-52.0
-57.5
-38.4
-8.2
-1.3
-5.6
-9.5
-14.2
0.0
-57.5B-54
TABLE B.10 EXAMPLE JIDA RESERVOIR REGULATION COMPUTER RUNS
STATION: BASIN 4 -JIDA MONTHLY RUNOFF in r3/i
JAN
FEB
WAR
APR
HAY
JUN
JUL
AU6
SEP
OCT
NOV
DEC
AV6
I
2
0.3
0.2
0.2
0.2
0.3
0.3
1.1
1.1
0.8
0.9
0.2
0.3
26.4
21.0
96.7
11.8
20.5
4.5
0.7
0.6
0.8
0.3
0.3
0.2
12.4
3.4
3
4
0.2
0.3
0.2
0.3
0.2
0.2
0.3
0.2
0.3
0.3
0.1
0.1
111.5 1.7
41.8
17.3
19.7
5.9
0.7
0.0
0.2
0.7
0.2
0.3
14.6 2.3
5
6
0.1
0.2
0.2
0.2
0.3
0.3
0.3
0.2
0.3
0.2
0.2
0.3
2B.7
23.2
54.7
62.8
8.1
7.4
0.3
0.5
0.6
1.0
0.3
0.3
7.8
8.1
7
8
0.3
0.3
0.4
0.3
0.3
0.1
0.2
0.2
0.2
0.2
0.2
8.1
31.9
25.8
127.9
35.1
18.2
14.5
1.3
1.2
0.8
1.0
9
10
0.3
0.2
15.2
7.3
0.2
0.3
0.2
0.3
0.3
0.9
0.3
0.5
0.3
0.5
ia.1
13.0
78.5
51.3
36.6
50.1
19.6
12.3
1.3
0.4
0.1
0.1
0.2
0.1
11
12
0.2
0.2
13.0
10.8
0.2
0.0
0.3
0.1
0.2
0.1
0.2
0.0
0.3
0.2
21.9
36.1
63.9
74.1
2.9
11.2
0.5
0.7
0.3
0.1
13
14
0.2
0.2
0.3
0.2
0.3
0.1
0.4
0.3
7.6 10.3
0.3
0.3
0.3
0.1
0.2
0.5
6.7
B3.0
52.4
42.6
5.0
7.3
0.4
0.3
15
16
0.3
0.3
0.1
0.2
0.2
0.2
0.2
0.3
0.2
0.9
0.5
0.4
5.6 11.2
1.2
0.3
0.4
0.2
23.3
9.1
55.1
36.4
8.3
16.6
0.5
0.4
17
18
19
20
0.2
0.2
0.2
0.1
0.2
0.1
0.2
0.3
0.8
0.1
0.2
0.1
0.4
0.2
0.1
1.1
7.6
5.4
0.3
0.7
0.7
0.1
0.9
0.2
21.9
2.8
1.0
42.2
30.7
41.6
6.1
7.4
12.0
0.3
0.6
0.1
0.6
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.3
0.2
6.0
3.6
4.9
0.0
24.0
35.1
50.4
11.8
0.6
0.9
0.2
6.1
0.2
0.2
0.3
0.4
0.4
2.2
31.5
10.9
0.6
0.4
0.3
8.2
Drainage Area: 749 ka*2
Specific Runoff: 343.6208 uTable B.10
Example Jida Reservoir Regulation Computer Runs - 2
CUMULATIVE STORAGE (in i*3/sl Draft Rati: 4.08 eA3/S
JAN
FEB
MAR
APR
MAY
JUN
JUL
AU6
SEP
OCT
NOV
DEC
SPILL
ST0RA6E
1
-3.8
-7.7
-11.5
-14.5
-17.8
-21.7
0.8
92.6
16.4
-3.3
-6.6
-10.4
109.8
-21.7
2
-14.2
-18.1
-21.9
-24.9
-28.1
-31.9
-15.0
-7.3
-6.9
-10.4
-14.1
-18.0
0.0
-31.9
3
-21.9
-25.8
-29.6
-33.4
-37.2
-41.1
66.2
37.8
15.6
-3.4
-7.2
-11.2
119.6
-41.1
4
-15.0
-18.1
-22.6
-26.5
-30.3
-34.3
-36.6
-23.5
-21.6
-25.7
-29.1
-32.9
0.0
-36.6
5
-36.8
-40.8
-44.5
-48.3
-52.0
-55.9
-31.3
19.3
4.0
-3.8
-7.3
-11.1
23.2
-55.9
6
-15.0
-18.8
-22.6
-26.5
-30.4
-34.2
-15.0
43.7
3.3
-3.6
-6.7
-10.4
47.0
-34.2
7
-14.2
-17.9
-21.7
-25.5
-29.4
-33.3
-5.5
118.4
14.1
-2.7
-6.0
-9.8
132.4
-33.3
8
-13.6
-17.4
-21.4
-25.3
-29.2
-25.1
-3.4
27.7
10.4
-2.8
-5.9
-9.8
38.1
-29.2
9
-13.7
-17.6
-21.3
-25.1
-28.9
-14.8
59.6
32.5
15.6
-2.8
-6.8
-10.7
107.7
-28.9
10
-14.4
-18.2
-21.4
-25.0
-28.6
-19.7
27.6
46.0
8.2
-3.7
-7.7
-11.6
81.8
-28.6
1!
-15.5
-19.4
-23.2
-27.1
-31.0
-34.8
-17.0
42.9
-1.2
-4.8
-8.7
-12.5
42.9
-34.8
12
-16.3
-20.4
-24.4
-28.4
-32.5
-36.3
-4.3
65.7
7.1
-3.4
-7.3
-11.2
72.9
-36.3
13
-15.0
-18.8
-22.5
-26.3
-30.0
-33.8
-31.2
17.1
0.9
-3.6
-7.6
-11.4
18.0
-33.8
14
-15.3
-19.3
-23.0
-26.8
-30.8
-34.4
44.5
38.5
3.2
-3.8
-7.7
-11.6
86.2
-34.4
13
-15.4
-19.2
-23.1
-26.7
-29.6
-33.2
-14.0
37.0
4.2
-3.5
-7.4
-10.7
41.2
-33.2
16
-14.5
-18.4
-21.5
-25.2
-29.0
-32.9
-27.8
4.5
12.5
-3.7
-7.5
-11.4
17.0
-32.9
17
-15.3
-19.3
-23.1
-27.0
-30.9
-34.8
-16.9
21.2
2.0
-3.5
-7.4
-11.3
23.2
-34.8
18
-15.1
-19.0
-22.9
-26.9
-30.3
-33.5
-34.8
-8.1
-4.8
-8.8
-12.7
-16.5
0.0
-34.8
19
-20.4
-24.4
-28.1
-31.1
-34.4
-38.3
-41.3
-3.8
4.1
-3.5
-7.3
-11.2
4.1
-41.3
20
-15.0
-18.9
-22.8
-26.7
-30.6
-34.7
-14.7
16.3
7.7
-3.5
-6.6
-10.5
24.0
-34.7
A
CUMULATIVE STORAGE (in « 3/s) Draft Rate: 4.89 iA3/S
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUS
SEP
OCT
NOV
DEC
SPILL
STORAGE
1
-4.6
-9.3
-13.9
-17.7
-21.9
-26.6
-4.9
86.9
15.6
-4.2
-8.2
-12.9
102.5
-26.6
2
-17.5
-22.2
-26.8
-30.7
-34.6
-39.2
-23.2
-16.3
-16.7
-21.0
-25.6
-30.2
0.0
-39.2
3
-34.9
-39.6
-44.3
-48.9
-53.5
-58.3
48.3
37.0
14.B
-4.2
-8.9
-13.6
100.0
-58.3
4
-18.2
-22.8
-27.5
-32.2
-36.8
-41.6
-44.8
-32.4
-31.4
-36.3
-40.5
-45.1
-54.6
0.0
5
-49.9
-59.2
-63. B
-45.1
-68.3
-73.1
-49.2
0.5
3.2
-4.6
-8.9
-13.5
3.7
6
-18.2
-22.9
-27.5
-32.2
-36.9
-73.1
-41.5
-23.2
34.8
2.5
-4.4
-8.3
-12.9
7
-17.4
-22.0
-26.6
-31.2
-35.9
37.2
-41.5
-40.6
-13.6
109.4
13.3
-3.6
-7.7
-16.9
-21.5
-26.3
-12.3
8
-31.0
-35.7
122.6
-40.6
-32.4
-11.0
18.7
9.6
-3.7
-16.9
-7.6
9
-21.6
-26.2
-30.8
-12.2
-35.4
28.3
-35.7
-22.1
51.4
31.7
14.7
-3.0
-8.4
-13.1
97.9
10
-17.7
-22.3
-26.3
-30.7
-35.1
-35.4
-27.1
19.4
45.2
7.4
-4.5
-9.3
-14.1
72.0
11
-18.8
-23.5
-28.1
-32.8
-37.5
-35.1
-42.2
-25.1
33.9
-2.0
-6.5
12
-20.4
-30.1
-11.1
-25.3
-34.9
-15.7
33.9
-39.8
-44.4
-42.2
-13.3
55.9
6.3
-4.2
-8.9
13
-18.3
-22.9
-27.4
-32.0
-13.6
-36.5
62.3
-44.4
-41.2
-39.3
B.2
0.1
-4.5
-27.9
-9.2
-13.9
14
-18.6
-23.3
-32.5
-37.3
8.2
-41.7
-41.2
36.3
37.7
2.4
-4.6
-9.4
-14.0
15
-18.6
-23.3
-28.0
-32.4
-36.1
76.4
-41.7
-40.6
-22.2
28.1
3.4
-4.4
-26.4
-9.0
-13.1
16
-17.8
-22.4
-30.9
-35.5
31.5
-40.3
-40.6
-36.0
-4.5
7.2
-4.5
-9.1
-13.9
17
-18.6
-23.4
-28.0
-32.7
-37.4
7.2
-42.1
-40.3
-25.1
12.2
1.2
-4.3
-18.4
-27.8
-9.0
-13.7
18
-23.0
-32.6
-36.8
13.4
-40.8
-42.9
-42.1
-17.1
-14.6
-19.4
-24.1
-42.8
-28.7
19
-33.5
-38.2
-4b.6
-50.7
-55.4
0.0
-42.9
-59.2
-22.6
-15.5
-19.8
-38.4
-47.9
-24.4
-29.2
20
-33.7
-43.1
-52.0
0.0
-57.5
-38.4
-59 2
-8.2
-1.3
-5.6
-9.5
-14.2
0.0
-57.5Table B.10
Example Jida Reservoir Regulation Computer Runs - 3
CUMULATIVE STORAGE (in «*3/s) Drift Rati: 3.71 i'3/S
B-56
JAN
FEB
MAR
APR
MAY
JUN
JUL
AU6
SEP
OCT
NOV
DEC
SPILL
STORAGE
I
-5.5
-10.9
-16.4
-21.0
-25.9
-31.5
-10.6
80.4
14.7
-5.0
-9.9
-15.3
95.1
-31.5
2
-20.8
-26.2
-31.7
-36.4
-41.2
-46.6
-31.3
-25.2
-26.4
-31.6
-37.0
-42.5
0.0
-46.6
3
-48.0
-53.5
-59.0
-64.4
-69.8
-75.4
30.4
36.1
14.0
-5.0
-10.5
-16.0
80.5
-75.4
4
-21.5
-26.9
-32.4
-37.9
-43.3
-49.0
-53.0
-41.4
-41.2
-46.9
-51.9
-57.4
0.0
-57.4
5
-62.9
-68.5
-73.9
-79.2
-84.6
-90.2
-67.2
-18.2
-15.9
-21.3
-26.4
-31.9
0.0
-90.2
6
-37.4
-42.9
-48.3
-53.8
-59.4
-64.7
-47.2
9.9
1.7
-5.2
-9.9
-15.3
11.6
-64.7
7
-20.7
-26.1
-31.5
-36.9
-42.4
-48.0
-21.8
100.4
12.4
-4.4
-9.3
-14.7
112.9
-48.0
a
-20.1
-25.6
-31.2
-36.7
-42.2
-39.8
-19.7
9.7
8.8
-4.5
-9.2
-14.7
18.5
-42.2
9
-20.2
-25.7
-31.1
-36.5
-41.9
-29.5
43.3
30.9
13.9
-4.4
-10.0
-15.5
88.1
-41.9
10
-21.0
-26.3
-31.1
-36.4
-41.7
-34.4
11.2
44.4
6.6
-5.4
-10.9
-16.5
62.2
-41.7
n
-22.0
-27.6
-33.0
-38.5
-44.0
-49.5
-33.3
24.9
-2.8
-8.1
-13.5
-19.0
24.9
-49.5
12
-24.5
-30.2
-35.8
-41.4
-47.1
-52.6
-22.2
46.2
5.5
-5.0
-10.6
-16.1
51.7
-52.6
13
-21.5
-27.0
-32.2
-37.7
-43.1
-48.5
-47.5
-0.8
-1.5
-6.8
-12.4
-17.9
0.0
-48.5
14
-23.4
-29.0
-34.3
-39.8
-45.4
-50.6
26.6
36.9
1.6
-5.4
-11.0
-16.4
65.1
-50.6
15
-21.9
-27.4
-32.9
-38.1
-42.6
-47.9
-30.3
19.1
2.6
-5.2
-10.6
-15.6
21.7
-47.9
16
-21.0
-26.5
-31.3
-36.6
-42.1
-47.6
-44.1
-13.4
-2.6
-7.9
-13.3
-18.9
0.0
-47.6
17
-24.4
-30.0
-35.5
-41.0
-46.5
-52.1
-35.8
0.7
0.4
-5.1
-10.7
-16.2
1.1
-52.1
IS
-21.7
-27.1
-32.7
-38.3
-43.4
-48.2
-51.1
-26.1
-24.4
-30.0
-35.5
-41.0
0.0
-51.1
19
-46.5
-52.1
-57.4
-62.1
-67.0
-72.5
-77.2
-41.3
-35.0
-40.1
-45.6
-51.2
0.0
-77.2
20
-56.6
-62.1
-67.6
-73.2
-78.7
-84.4
-66.1
-36.7
-30.6
-35.7
-40.5
-46.0
0.0
-84.4
A
CUMULATIVE STORAGE (in i 3/«) Drift Rati: 6.52 i'3/S
JAN
FEB
MAR
APR
NAY
JUN
JUL
AU6
SEP
OCT
NOV
DEC
SPILL
ST0RA6E
I
-6.3
-12.6
-18.8
-24.3
-30.0
-36.4
-16.3
73.9
13.9
-5.8
-11.5
-17.7
87.B
-36.4
2
-24.0
-30.3
-36.6
-42.1
-47.7
-53.9
-39.5
-34.2
-36.2
-42.2
-48.4
-54.7
0.0
-54.7
3
-61.0
-67.4
-73.7
-79.9
-86.1
-92.5
12.4
35.3
13.2
-5.8
-12.1
-18.5
60.9
-92.5
4
-24.7
-31.0
-37.3
-43.6
-49.8
-56.3
-61.1
-50.4
-51.0
-57.5
-63.3
-69.6
0.0
-69.6
5
-76.0
-82.4
-88.6
-94.7
-101.0
-107.3
-85.1
-37.0
-35.5
-41.7
-47.6
-53.9
0.0
-107.3
6
-e0.2
-66.6
-72.8
-79.1
-85.5
-91.6
-74.9
-18.7
-17.8
-23.8
-29.4
-35.6
0.0
-91.6
7
-41.8
-47.9
-54.2
-60.5
-66.7
-73.1
-47.7
73.6
11.6
-5.2
-10.9
-17.2
85.3
-73.1
8
-23.4
-29.6
-36.0
-42.4
-48.7
-47.1
-27.9
0.7
8.0
-5.3
-10.8
-17.1
8.7
9
-23.4
-29.8
-36.0
-42.2
-48.4
-36.8
35.1
30.1
-48.7
13.1
-5.3
-11.7
-18.0
78.3
-*8.4
10
-24.2
-30.4
-36.0
-42.1
-48.2
-41.7
3.1
43.6
5.7
-6.2
-12.6
-50.6
-56.8
-41.4
-19.0
52.4
-48.2
11
-25.3
-31.6
-37.9
-44.2
16.0
-3.7
-9.7
-16.0
-22.3
16.0
-56.8
12
-28.6
-35.1
-41.5
-47.9
-54.5
-60.8
-31.2
36.4
4.7
-5.8
-12.2
-18.5
41.1
U-6V0i .o8
13
-24.8
-31.1
-37.1
-43.4
-49.6
-55.9
-55.6
-9.8
-11.3
-17.4
-23.8
-30.1
14
-36.4
-42.8
-49.0
-55.3
-61.7
-67.8
8.7
36.1
0.0
0.7
w-w55. 79
-6.3
-12.6
-18.9
45.5
15
-25.2
-31.5
-37.7
-43.8
-49.1
-55.2
-38.5
10.1
1.8
U-6r7• fQi
-6.0
-12.3
-36.2
-42.3
-48.6
-54.9
-52.3
-18.0
16
-24.3
-30.6
-22.4
11 9
-55 7
-12.4
-18.5
-24.7
-56.5
-62.8
-68.4
-69.2
-74.0
-53.8
-77.7
-18.1
-53.6
-31.1
17
18
19
20
-37.5
-43.4
-43.9
-50.2
-56.1
-90.6
-110.6
V0. Vfl
-49.7
-62.5
-78.1
-84.5
-96.1
-101.9
-113.6
-78.6
-97.9
-104.2
-117.0
-123.3
-108.2
-129.8
-112.3
-83.8
-18.5
-52.7
-73.1
-78.5
-24.5
-30.8
-37.1
-59.1
-65.5
-71.7
-79.1
-69.2
-77.7
-85.3
-91.7
-84.4
0.0
0.0
0.0
0.0
-113.6
-90.0
-96.3
-129.8Table B.10
Example Jida Reservoir Regulation Computer Runs - 4
CUMULATIVE STORAGE (in a 3/s) Drift Rati: 7.34 aA3/S
B-57
A
1
JAN
-7.1
FEB
-14.2
MAR
-21.3
APR
-27.5
MAY
-34,1
JUN
-41.3
JUL
-22.0
AU6        SEP       OCT       NOV       DEC      SPILL    ST0RA6E
2 -27.3 -34.4 -41.5 -47.8 -54.2 -61.3 -47.6
3 -74.1 -81.2 -88.4 -95.4 -102.4 -109.7 -5.5
4 -28.0 -35.1 -42.2 -49.3 -56.4 -63.7 -69.3
5 -89.0 -96.2 -103.2 -110.2 -117.3 -124.4 -103.1
-13.1 -20.2 80.5 -41.3
-59.8 -66.9 0.0 -66.9
-13.8       -20.9        41.3
-109.7
-74.8 -81.8 0.0
-68.8 -75.9 0.0
-81.8
-124.4
6       -83.1      -90.2
7       -74.4      -81.4
S       -26.7      -33.7
9       -27.8      -35.0
10       -27.5      -34.5
11       -28.5      -35.7
12       -32.7      -40.0
13       -28.1      -35.1
14       -49.5      -56.7
15 -28.5 -35.6
16 -27.5 -34.7
17 -50.5 -57.8
IB -66.3 -73.4
19 -110.7 -117.9
20 -140.3 -147.5
-97.3 -104.4 -111.6 -118.6 -102.7 -88.4 -95.5 -102.6 -109.8 -85.3 -40.9 -48.1 -55.3 -54.5 -36.0 -42.0 -49.0 -56.0 -45.2 25.9 -40.9 -47.8 -54.7 -49.1 -5.1 -42.8 -49.9 -57.1 -64.2 -49.6 -47.2 -54.5 -61.8 -68.9 -40.2 -42.0 -49.1 -56.1 -63.2 -63.8 -63.7 -70.8 -78.0 -84.9 -9.2 -42.7 -49.6 -55.8 -62.7 -46.7 -41.1 -48.1 -55.1 -62.3 -60.5 -64.9 -72.0 -79.1 -86.3 -71.7 -80.6 -87.8 -94.5 -100.9 -105.5
-124.9 -131.1 -137.8 -144.9 -151.2 -154.6 -161.8 -169.0 -176.3 -159.6
67.3        13.1        -6.6 -43.2       -46.0       -52.8
29.0        12.3        -6.7 -59.4       -60.8       -68.1 -55.8       -55.1      -62.1
-47.2       -47.2       -54.0
35.3        10.8        -6.0
-8.2         -1.1        -7.2
29.3        12.3        -6.1
37.7          4.9        -7.0
7.0        -4.5       -11.4
26.6          3.9        -6.6
-18.8      -21.1       -28.0
26.0        -0.1        -7.2
1.1          0.9        -6.8
-31.4 -22.2 -29.1 -36.9 -38.1 -44.8 -82.1 -82.1 -89.3
-60.4       -67.4          0.0
-118.6
-12.6 -19.6 46.1
-13.5       -20.7          0.0
-13.3       -20.4        67.4
-14.2       -21.4        42.6
-18.4 -25.5 7.0
-13.8 -21.0 30.4
-35.2       -42.3          0.0
-14.3       -21.4        26.0
-13.9       -20.5          2.0
-36.2       -43.4          0.0
-52.0       -59.2          0.0
-96.4     -103.5          0.0
-109.8
-55.3
-56.0
-54.7
-64.2
-68.9
-63.8
-84.9
-62.7
-62.3
-86.3
-105.5
-116.9     -112.3    -119.0
-126.1     -133.3          0.0
-151.2
-131.9    -127.4    -134.2
-140.6     -147.7          0.0
-176.3
A
CUMULATIVE ST0RA6E (in a 3/s) Drift Rita: 8.16 aA3/S
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUS
SEP
OCT
NOV
-7.9
-15.8
-23.7
DEC
-30.8
SPILL
1
ST0RA6E
-38.2
-46.2
-27.7
60.8
12.3
-7.4
-14.8
-22.6
2
-30.6
-38.5
-46.4
-53.5
73.1
-46.2
-60.7
-68.6
-55.8
-52.2
-55.8
-63.4
-71.2
3
-87.1
-95.1
-103.0
-110.9
-79.2
0.0
-118.7
-79.2
-126.8
-23.5
10.2
11.5
-7.5
-15.4
4
-31.3
-39.1
-47.1
-23.4
-55.0
-62.9
21.S
-126.8
-71.0
-77.4
-68.3
-70.6
-78.7
-86.2
-94.1
5
-102.1
-110.1
-117.9
-125.7
0.0
-94.1
-133.6
-141.6
-121.0
-74.5
-74.6
-82.5
-90.0
-97.9
6
-105.9
-113.9
-121.7
-129.7
0.0
-137.6
-141.6
-145.5
-130.4
-75.8
-76.5
-84.2
-91.3
7
-107.0
-114.8
-122.7
-130.6
-99.2
0.0
-138.5
-145.5
-146.5
-122.8
-3.0
7.0
-6.8
-14.2
-22.1
8
-29.9
-37.8
-45.8
-53.8
-61.8
7.0
-146.5
-61.8
-44.2
-17.2
-10.9
-17.8
-46.8
-56.7
-25.0
-32.9
9
-40.8
-64.5
-72.4
0.0
-62.4
-61.8
7.9
28.4
11.5
-6.9
-14.9
-22.9
10
-30.7
-38.6
-45.8
-53.5
47.9
-61.2
-72.4
-56.4
-13.2
28.7
4.1
-7.8
11
-47.7
-15.8
-31.8
-39,8
-55.6
-23.9
-63.6
J2.8
-61.2
-71.5
-57.7
-2.0
-7.3
-15.0
-22.9
12
-38.7
-46.8
-54.9
-63.0
-71.1
-30.8
0.0
-79.0
-71.5
-51.1
14.8
3.1
-7.4
-46.9
-15.5
-23.4
17.9
13
-31.3
-39.2
-54.8
-62.6
-70.5
-79.0
-72.0
-27.7
-30.9
-38.6
-78.4
-46.6
14
-62.5
-70.6
-86.3
-54.6
-94.3
0.0
-72.0
-102.0
-27.2
7.3
-0.9
-8.8
-16.8
15
-32.6
-40.5
-48.4
-56.1
-24.7
-63.1
7.3
-70.8
-102.0
-55.7
-8.7
-8.6
-16.2
-24.1
16
-39.4
-47.3
-54.6
-62.3
-31.5
0.0
-70.2
-70.8
-78.2
-77.2
-48.9
-40.5
-48.3
-56.2
-64.2
0.0
17
-72.2
-80.2
-88.1
-96.1
-104.0
-112.0
-78.2
-98.2
-64.2
-66.2
-73.8
-81.8
18
-97.7
-105.o
-113.6
-121.7
-89.8
-129.2
0.0
-136.4
-112.0
-141.8
-119.2
-120.0
-128.1
-136.0
-143.9
19
-151.9
-159.9
-167.7
-174.8
-182.2
0.0
-190.1
-143.9
-197.3
-163.8
-160.0
-167.6
-175.5
-183.5
20
-191.3
-199.3
-207.3
-215.3
-223.2
0.0
-231.4
-197.3
-215.5
-188.6
-185.0
-192.5
-199.7
-207.7
0.0
-231.4Table B.10
Example Jida Reservoir Regulation Computer Runs - 3
CUMULATIVE STORAGE (in a 3/s)
Drift Rite:          5.71 eA3/S
B-56
A
1
2
3
4
5
a
7
8
9
10
11
12
13
15
16
17
18
19
20
JAN        FEB        MAR       APR        NAY        JUN        JUL        AU6       SEP       OCT       NOV       DEC     SPILL    STQRA6E -5.5        -10.9       -16.4       -21.0       -25.9       -31.5       -10.6        80.4        14.7        -5.0        -9.9      -15.3        95.1    "31 • 5
■it
-20. B       -26.2       -31.7       -36.4       -41.2       -46.6       -31.3       -25.2      -26.4      -31.6      -37.0      -42.5
0.0     ”46«6
-48.0        -53.5       -59.0       -64.4       -69.8       -75.4        30.4        36.1        14.0        -5.0      -10.5      -16.0       80* 5     -75. 4
-21.5        -26.9       -32.4       -37.9       -43.3       -49.0       -53.0       -41.4      -41.2      -46.9      -51.9      -57.4          0.0       -57.4
If 1
-62.9        -68.5       -73.9       -79.2       -84.6       -90.2       -67.2       -18.2      -15.9      -21.3      -26.4      -31.9          0.0
BA A
-90.2
-37.4        -42.9       -48.3       -53.8       -59.4       -64.7       -47.2          9.9          1.7        -5.2        -9.9      -15.3        11.6       -64.7
-20.7        -26.1       -31.5       -36.9       -42.4       -48.0       -21.8      100.4        12.4        -4.4        -9.3      -14.7      112.9      -4B.0
-20.1        -25.6       -31.2       -36.7       -42.2       -39.8       -19.7          9.7          8.8        -4.5        -9.2      -14.7        18.5      -42.2
-20.2        -25.7       -31.1       -36.5       -41.9       -29.5        43.3        30.9        13.9        -4.4      -10.0      -15.5        88.1       -41.9
-21.0 -26.3 -31.1 -36.4 -41.7 -34.4 11.2 44.4 6.6 -5.4 -10.9 -16.5 62.2 -41.7 -22.0 -27.6 -33.0 -38.5 -44.0 -49.5 -33.3 24.9 -2.8 -8.1 -13.5 -19.0 24.9 -49.5 -24.5 -30.2 -35.8 -41.4 -47.1 -52.6 -22.2 46.2 5.5 -5.0 -10.6 -16.1 51.7 -52.6 -21.5 -27.0 -32.2 -37.7 -43.1 -48.5 -47.5 -0.8 -1.5 -6.8 -12.4 -17.9 0.0 -40.5
14 -23.4 -29.0 -34.3 -39.8 -45.4 -50.6 26.o 36.9 1.6 -5.4 -11.0 -16.4 65.1 -50.6
-21.9        -27.4       -32.9       -38.1       -42.6       -47.9       -30.3        19.1          2.6        -5.2      -10.a      -15.6        21.7      -47.9
-21.0        -26.5       -31.3       -36.6       -42.1       -47.6       -44.1       -13.4        -2.6        -7.9      -13.3      -1B.9          0.0      -47.6
-24.4        -30.0       -35.5       -41.0       -46.5       -52.1       -35.8          0.7          0.4        -5.1      -10.7      -16.2        1.1     -52.1
-21.7        -27.1       -32.7       -38.3       -43.4       -48.2       -51.1      -26.1       -24.4      -30.0      -35.5      -41.0          0.0      -51.1
-46.5        -52.1       -57.4       -62.1       -67.0       -72.5       -77.2      -41.3      -35.0      -40.1      -45.6      -51.2          0.0      -77.2
-56.6       -62.1       -67.6       -73.2       -78.7       -84.4       -66.1       -36.7      -30.6      -35.7      -40.5      -46.0          0.0       -84.4
A
CUMULATIVE ST0RA6E (in e 3/s)
Drift Rite: 6.52 e'3/S
JAN FEB MAR APR        MAY       JUN        JUL        AU6      SEP        OCT       NOV       DEC     SPILL    STORAGE
1
-a.3
-12.6
-18.8
-24.3
-30.0
-36.4
-16.3
73.9
13.9
-5.8
-11.5
-17.7
87.8
-36.4
2
-24.0
-30.3
-36.6
-42.1
-47.7
-53.9
-39.5
-34.2
-36.2
-42.2
-48.4
-54.7
0.0
-54.7
3
-61.0
-67.4
-73.7
-79.9
-86.1
-92.5
12.4
35.3
13.2
-5.8
-12.1
-18.5
60.9
-92.5
4
-24.7
-31.0
-37.3
-43.6
-49.8
-56.3
-61.1
-50.4
-51.0
-57.5
-63.3
-69.6
0.0
-69.6
5
-76.0
-82.4
-88.6
-94.7
-101.0
-107.3
-85.1
-37.0
-35.5
-41.7
-47.6
-53.9
0.0
-107.3
6
-60.2
-66.6
-72.8
-79.1
-85.5
-91.6
-74.9
-18.7
-17.8
-23.8
-29.4
-35.6
0.0
-91.6
7
-41.8
-47.9
-54.2
-60.5
-66.7
-73.1
-47.7
73.6
11.6
-5.2
-10.9
-17.2
85.3
-73.1
8
-23.4
-29.6
-36.0
-42.4
-48.7
-47.1
-27.9
0.7
8.0
-5.3
-10.8
-17.1
8.7
-48.7
9
-23.4
-29.8
-36.0
-42.2
-48.4
-36.8
35.1
30.1
13.1
-5.3
-11.7
-18.0
78.3
-48.4
10
-24.2
-30.4
-36.0
-42.1
-48.2
-41.7
3.1
43.6
5.7
-6.2
-12.6
-19.0
52.4
-48.2
11
-25.3
-31.6
-37.9
-44.2
-50.6
-56.8
-41.4
16.0
-3.7
-9.7
-16.0
-22.3
16.0
-56.8
12
-2B.6
-35.1
-41.5
-47.9
-54.5
-60.8
-31.2
36.4
4.7
-5.8
-12.2
-18.5
41.1
-60.8
13
-24.e
-31.1
-37.1
-43.4
-49.6
-55.9
-55.6
-9.8
-11.3
-17.4
-23.8
-30.1
0.0
-55.9
14
-36.4
-42.8
-49,0
-55.3
-61.7
-67.8
B.7
36.1
0.7
-6.3
-12.6
-18.9
45.5
-67.8
15
-25.2
-31.5
-37.7
-43.8
-49.1
-55.2
-38.5
10.1
1.8
-6.0
-12.3
-18.0
11.9
-55.2
16
-24.3
-30.6
-36.2
-42.3
-48.6
-54.9
-52.3
-22.4
-12.4
-18.5
-24.7
-31.1
0.0
-54.9
17
-37.5
-43.9
-50.2
-56.5
-.2.8
-69.2
-53.8
-18.1
-18.5
-24,5
-30.8
-37.1
0.0
-69.2
18 
-43.4
*49.7
-56.1
-62.5
-68.4
-74.0
-77.7
-53.6
-52.7
-59.1
-65.5
-71.7
0.0
-77.7
19
-78.1
-84.5
-90.6
-96.1
-101.9
-108.2
-113.6
-78.6
-73.1
-79.1
-85.3
-91.7
0.0
-113.6
20
-97.9
-104.2
-110.6
-117.0
-123.3
-129.8
-112.3
-83.8
-78.5
-84.4
-90.0
-96.3
0.0
-129.8Table B.10
Example Jida Reservoir Regulation Computer Runs - 4
B-57
CUMULATIVE STORAGE (in
Drift Rati: 7.34 i*3/S
JAM         FEB        MAR        APR        MAY         JUN          JUL         AUG         SEP         OCT         NOV         DEC        SPILL    STORAGE
1           -7.1        -14.2        -21.3        -27.5        -34.1        -41.3        -22.0          67.3          13.1          -6.6
2         -27.3        -34.4        -41.5        -47.8        -54.2        -61.3        -47.6        -43.2        -46.0        -52.8
3         -74.1        -81.2        -88.4        -95.4     -102.4      -109.7           -5.5          29.0          12.3         -6.7
4         -28.0        -35.1        -42.2        -49.3        -56.4        -63.7        -69.3        -59.4        -60.8        -«8.1
5         -89.0        -96.2     -103.2      -110.2      -117.3      -124.4      -103.1          -55.8         -55.1        -62.1
6         -83.1        -90.2        -97.3     -104.4      -111.6      -118.6      -102.7          -47.2        -47.2        -54.0
7         -74.4        -81.4        -88.4        -95.5     -102.6      -109.8          -85.3          35.3          10.8          -6.0
9         -26.7        -33.7        -40.9        -48.1        -55.3        -54.5        -36.0          -8.2           -1.1          -7.2
9         -27.8        -35.0        -42.0        -49.0        -56.0        -45.2          25.9          29.3          12.3         -6.1
10         -27.5        -34.5        -40.9        -47.8        -54.7        -49.1          -5.1          37.7            4.9          -7.0
11         -28.5        -35.7        -42.8        -49.9        -57.1        -64.2        -49.6             7.0          -4.5        -11.4
12         -32.7        -40.0        -47.2        -54.5        -61.8        -68.9        -40.2          26.6            3.9          -6.6
13         -28.1        -35.1        -42.0        -49.1        -56.1        -63.2        -63.8        -18.8        -21.1         -28.0
14         -49.5        -56.7        -63.7        -70.8        -78.0        -84.9          -9.2          26.0           -0.1          -7.2
15         -28.5        -35.6        -42.7        -49.6        -55.8        -62.7        -46.7            1.1            0.9          -6.8
16         -27.5        -34.7        -41.1        -48.1        -55.1         -62.3        -60.5        -31.4        -22.2        -29.1 17         -50.5        -57.8        -64.9        -72.0        -79.1        -86.3        -71.7        -36.9         -38.1        -44.8 IB         -66.3        -73.4        -80.6        -87.8        -94.5     -100.9       -105.5          -82.1         -82.1        -89.3 19      -110.7      -117.9      -124.9      -131.1      -137.8      -144.9       -151.2         -116.9       -112.3    -119.0 20      -140.3      -147.5      -154.6      -161.8      -169.0      -176.3      -159.6         -131.9      -127.4    -134.2
-13.1         -20.2           80.5        -41.3
-59.8        -66.9             0.0        -66.9
-13.8        -20.9           41.3      -109.7
-74.8        -81.8             0.0        -81.8
-68.8        -75.9             0.0      -124.4
-60.4        -67.4             0.0      -118.6
-12.6         -19.6          46.1       -109.8
-13.5         -20.7             0.0        -55.3
-13.3        -20.4           67.4         -56.0
-14.2        -21.4           42.6        -54.7
-18.4         -25.5             7.0        -64.2
-13.8        -21.0           30.4         -68.9
-35.2         -42.3             0.0        -63.8
-14.3        -21.4           26.0        -84.9
-13.9         -20.5             2.0         -62.7
-36.2        -43.4             0.0         -62.3
-52.0        -59.2             0.0         -86.3
-96.4      -103.5             0.0       -105.5
-126.1 -133.3 0.0 -151.2
-140.6 -147.7 0.0 -176.3
CUMULATIVE STORAGE (in «*3/s)
Drift Rati: 8.16 ■''3/S
JAN         FEB         MAR        APR         HAY         JUN          JUL
1           -7.9        -15.8        -23.7        -30.8        -38.2        -46.2         -27.7
2         -30.6        -38.5        -46.4        -53.5        -60.7        -68.6         -55.8
3         -87.1        -95.1      -103.0      -110.9      -118.7      -126.8          -23.5
4         -31.3        -39.1        -47.1        -55.0        -62.9        -71.0          -77.4
5       -102.1      -110.1      -117.9      -125.7      -133.6      -141.6        -121.0
6       -105.9      -113.9      -121.7      -129.7      -137.6      -145.5       -130.4
7       -107.0      -114.8      -122.7      -130.6      -138.5      -146.5        -122.8
8         -29.9        -37.8        -45.8        -53.8        -61.8        -61.8         -44.2
9         -40.8        -48.8        -5n.7        -64.5        -72.4        -62.4             7.9
10 -30.7 -38.6 -45.8 -53.5 -61.2 -56.4 -13.2
11 -31.8 -39.8 -47.7 -55.6 -63.6 -71.5 -57.7
12 -38.7 -46.8 -54.9 -63.0 -71.1 -79.0 -51.1
13         -31.3        -39.2       -4e. 9        -54.8        -62.6        -70.5         -72.0
14         -62.5        -70.6        -78.4        -86.3        -94.3      -102.0          -27.2
15         -32.6        -40.5        -48.4        -56.1        -63.1         -70.8        -55.7
16         -39.4        -47.3        -54.6        -62.3        -70.2        -78.2          -77.2
17         -72.2        -80.2        -88.1        -96.1      -104.0      -112.0         -98.2
18         -97.7      -105.o      -113.6      -121.7      -129.2      -136.4        -141.8
19 -151.9 -159.9 -167.7 -174.8 -182.2 -190.1 -197.3
20      -191.3 -(99.3 -207.3 -215.3 -223.2 -231.4 -215.5
AU6 SEP OCT NOV DEC SPILL STORAGE
60.8          12.3         -7.4        -14.8         -22.6          73.1         -46.2
-52.2       -55.8         -63.4         -71.2         -79.2             0.0         -79.2
10.2          11.5          -7.5        -15.4        -23.4           21.8       -126.8
-68.3 -70.6 -78.7 -86.2 -94.1 0.0 -94.1 -74.5 -74.6 -82.5 -90.0 -97.9 0.0 -141.6
-75.8       -76.5         -84.2        -91.3         -99.2             0.0       -145.5
-3.0             7.0          -6.8        -14.2        -22.1             7.0       -146.5
-17.2        -10.9        -17.8         -25.0         -32.9             0.0         -61.8
28.4          11.5          -6.9        -14.9         -22.9           47.9         -72.4 28.7            4.1          -7.8        -15.8         -23.9           32.8         -61.2 -2.0           -7.3        -15.0         -22.9         -30.8             0.0         -71.5
14.8            3.1          -7.4         -15.5         -23.4           17.9         -79.0
-27.7         -30.9       -38.6         -46.6         -54.6             0.0         -72.0
7.3          -0.9          -8.8         -16.8         -24.7             7.3       -102.0
-8.7           -8.6        -16.2        -24.1         -31.5             0.0         -70.8
-46.9 -40.5 -‘8.3 -56.2 -e4.2 0.0 -78.2 -64.2 -6e.2 -73.8 -81.8 -89.8 0.0 -112.0
-119.2 -120.0 -128.1 -136.0 -143.9 0.0 -143.9 -163.8 -160.0 -167.6 -175.5 -183.5 0.0 -197.3 -188.6 -185.0 -192.5 -199.7 -207.7 0.0 -231.4Table B.10
Example Jida Reservoir Regulation Computer Runs - 5
B-58
Drift        Has Storage
Graft
Rite
Required
Spillige
Vol mi
Runoff
■ A3/S
N« A3
Ni A3
lta A3
lta A3
4.1          -146.9          2598.1         2570.5           5141.1
4.9          -191.9          2093.7         3084.7           5141.1
5.7          -236.9          16&3.1         3598.8           5141.1
6.5          -341.0          1281.2         4112.9           5141.1
7.3         -463.1            902.0         4627.0           5141.1
8.2          -607.8            545.4         5141.1           5141.1TABLE B.11
RESERVO1R-REGULATION
RELATIONSHIPS FOR
FINAL MODEL RUNS
Reservoir Volume
Required (Mm ) in
3
3
Long-Term Reservoir Volume Required (Mm )
Drainage Mean Annual for Degree of Regulation (%) Runs for Degree of
Preliminary Model
Site
Subbasin
Ar ea
Flow
50
60
70
80
90
100
Regulation - 100%
2
(km )
3
(m /s)
5b
Tiliku
4 58
5.57
66.3
106.8
149.2
202.9
297.7
401.1
317.1
Al elt u
6c
Ji da
749
8. 16
148.2
193.2
238.2
372.5
525.5
707.2
512.6
8a
Gomoro
225
2.41
27.5
35.9
49.3
73.4
129.8
198.0
169.1
9a
Robi
4 37
4.29
49.8
73.4
97.1
132.9
197.1
279.5
286.7
2a
Weserbi
168
2.30
28.5
42.2
72.6
107.7
143.1
182.0
130.8
12c
Duber
312
3.98
53.3
75.3
100.1
134.6
169.0
216.5
221.1
14a
Cbacha
590
6. 19
74.1
109.8
145.6
193.7
249.0
304.3
566.3
10a
Jinjer
2 38
2.24
40.3
52.6
65.9
97.0
133.0
189.8
160.4
4b
Ti nishu
37
0.47
5.6
6.8
9.1
11.7
15.3
20.4
-
Aleltu
7b
Robi -
272
2.79
32.1
44.6
60.1
85.7
139.2
204.9
-
GomoroB-60
regional frequency analysis was undertaken. For this pur
pose, extensive use was made of data collected for the 1982 Power Planning Study (PPS) and a total of 15 recording stations located on the Ethiopian plateau in the Blue Nile, Omo and Awash basins was considered.
Table B.12, Columns 1 to 6, contains a listing of these stations, their period of record, drainage area and the mean annual flood (MAF). Instantaneous peak flow data were not available for most of the recording stations and, Dased on assumptions made in tne PPS, a ratio of instantaneous peak flow to daily peak flow of 1.4 was adopted.
The MAF for each station was calculated as the arithmetic mean of the annual maximum instantaneous peax flows over the recording period.
B7.2 - Frequency Curves
As a first step in the regional analysis, flood frequency curves were calculated for all of the gauging stations using a 2-parameter lognormal probability function. This function was selected to provide the most consistently reliable solu tion for the short lengths of the available recordings. Because of the short lengths, the computed relationships do not permit reliable estimates to be made of extremely rare flood events, such as tne probable maximum flood (PMF). However, for the purpose of preliminary sizing cf structural components for the various subbasin developments, extrapola tions were carried out for a recurrence interval of
1:10 000 years. Additional studies will be required during future study phases to confirm the calculated flood flow values and to obtain reliable estimates of the PMF.TABLE B.12
RESULTS OF FLOOD
HYDROLOGY ANALYSIS
(1)
Bas 1 n
(2)
No,
(3)
River Gauging
Station
(4)
Per 1od
of
Record
(yr)
(5)
Drainage
Area*
(km2)
(6)
Mean
Annual
Flood*
(m3/s)
(7)
Statistical
Flood**
(ip/s)
(8)
Return
Period of
Statistical
Flood
(yr)
(9)
9 1.05
(m5/s)
(10)
Q 1.05/MAF
(-)
(11)
Q 20
(m^/s)
(12)
020^
(-)
B 1 ue
1
Chemoga near Debre
18
364
59
87
10.0
32
0.54
98
1.66
NlJe
Markos
2
Beressa near Debre
17
211
89
132
8.3
41
0.46
163
1.83
Berhan
3
Dabana near
18
3 281
278
411
22.2
182
0.65
403
1.45
Abas Ina
4
Amartl near Shambu
16
24 5
35
52
10.0
18
0.51
60
1.71
5
DIdessa near Arjo
10
9 981
810
1 199
21.3
521
0.64
1 192
1.47
6
Neshe near Shambu
17
322
30
44
11.1
17
0.57
48
1.61
7
Muger near Chancho
16
489
81
120
5.9
29
0.36
171
2.11
8
Chacha at Chacha
14
418
101
149
6.5
33
0.33
212
2.10
Omo 9 GlIgel Gibe near 14 2 966 177 262
Asendabo
20.4                    112          0.64                  261          1.48
10
GlIgel Glbe near
17
4 230
287
425
21.7
185
0.64
418
1.46
Deneba
11
Great Gibe at
15
15 746
1 009
1 493
33.3
691
0.68
1 412
1.40
Abaltl
12
Wabe near Wolkltle
12
1 866
345
511
6.7
143
0.41
692
2.01
13
Walga near
18
1 792
185
274
6.9
76
0.41
366
1.97
Wolkltle
14
Gogeb near Shebo
9
3 494
282
417
11.8
157
0.56
461
1.64
Awash
15
Awash near Melka
16
4 440
266
394
14.2
142
0.53
415
1.56
Konture
• For other slat Ion data, such as locations, recording length, etc, see the October 1982 PPS by Acres International Limited. (Column 6, maximum Installation.)
■■Mean annual flood of each station times average 10-yr ratio equals mean 1:IO-yr flood over 15 stations
MAF x ----------------
1
mean annual flood over 15 stations
----------------------------------------     1.48 x MAF3-62
B7.3 - Homogeneity Test
To assess if all of the gauging stations would represent a homogeneous hydrologic region, a Langbein homogeneity test was carried out. This test is based on comparing the slopes
of individual frequency curves to a mean curve calculated for the region. For this purpose, a statistical flood for each station was computed as follows.
Statistical               Flood =
 mean l:10-yr flood* 
MAF x               --                   — mean annual flood*
Table B.12, Columns 7 and 8, shows the statistical floods and their corresponding return periods. The results are plotted in the Langbein graph shown on Plate B-3, Figure 4. This graph contains 95% confidence limits and, as all points fall well within these limits, it was concluded that the 15 
stations can be considered to represent a homogeneous hydrologic region.
B7.4 - Flood Index Factors
Table B.12, Columns 9 to 12, summarizes flood peaks and ratios for the 1:1.05- and l:20-yr recurrence intervals. The
nondimensional values of Q
peaR M
/  AF for each station were
"Average over 15 stations.B-63
plotted to determine the flood index (FI) factors, which are
defined as the regional mean relationships between flood 
peaks and MAF. Table B.13 shows the derived FI factors.
B7.5 - Mean Annual Floods
The remaining  part of the flood  frequency  analysis consisted of determining  the relationship  between  the MAF and  drainage area.
For this purpose, the values in Columns 5 and 6, Table B.12, were plotted as shown on Plate B-3, Figure 5. A regression analysis, based on the least square method, was carried out to mathematically define the relationship. The following function was found.
MAF = 0.84       X A where
0.73
Gp = FI x (0.84 x A '
MAF = mean annual flood
A = the drainage area (km2)
B7.6 - Peak Flood Calculations
The 1:20- and 1:10 000-yr peak floods of the Aleltu schemes were calculated using the MAF function and FI factors as follows.
0 73)B-64
I.’.LEX FACTORS
Ev*-r.t
Index
Factor
*At' i-'.-j. f-'X.'i
1.00
* ; 5-7 r
1.25
1.45
>six-7'
»</'f»
1.60
1.83
2.00
2.56
3.10B-65
where
Qp = he peak flood with a recurrence interval correspond 
t
ing to that of the FI factor
FI = flood index factor
A = drainage area (km2)
Table B.14 shows the computed peak flows for the subbasins.
B7.7 - Inflow Hydrographs
In order to assess peak flood flow attenuation during reser voir surcharge conditions, the determination of flood inflow hydrographs to the reservoir was required. Use was made of daily peak recordings at the Chacha gauging station to derive nondimensional hydrograph shapes. These were plotted over a period of about 8 days for the four highest peak floods on record and an eye-fit average nondimensional shape was determined as shown on Plate B-3, Figure 6 (solid lines). It
is noted that the hydrograph base flow corresponds to about 10% of the peak flow. The nondimensional nydrograph shape was simplified by adopting a 6—d base period and a triangular configuration, as shown on Plate B-3, Figure 6 (dotted line). To reflect different response times of each subbasin consi dered, the base period of the hydrograph was multiplied by the ratio of the subbasin drainage area to that of the Chacha drainage area.B-64
TABLE B.13
FLOOD INDEX FACTORS
Flood Event
Mean annual flood
Index Factor 1.00
1:5-yr
1.25
1:10-yr
1.45
1:20-yr
1.60
1:50-yr
1.83
l:100-yr
2.00
1:1 000-yr
2.56
1:10 000-yr
3.10B-65
where
Qp = the peak flood with a recurrence interval correspond 
ing to that of the FI factor
FI = flood index factor
A = drainage area (km2j
Table B.14 shows the computed peak flows for the subbasins.
B7.7 - Inflow Hydrographs
In order to assess peak flood flow attenuation during reser voir surcharge conditions, the determination of flood inflow hydrographs to the reservoir was required. Use was made of daily peak recordings at the Chacha gauging station to derive nondimensional hydrograph shapes. These were plotted over a period of about 8 days for the four highest peak floods on record and an eye-fit average nondimensional shape was determined as shown on Plate B-3, Figure 6 (solid lines). It
is noted that the hydrograph base flow corresponds to aDout 10% of the peak flow. The nondimensional hydrograph shape was simplified by adopting a 6-d base period and a triangular configuration, as shown on Plate B-3, Figure 6 (dotted line). To reflect different response times of each subbasin consi dered, the base period of the hydrograph was multiplied by the ratio of the subbasin drainage area to that of the Chacha drainage area.B-66
TABLE B. 14
COMPUTED PEAK FLOWS
Site         Subbasin
Drainage
Area
2
(km )
J
Flood Flow (m /s)
MAF g20 Q50 g100 210 000
3a
Agat
92
22.8
36.5
41.7
45.6
70.6
4b
Tinishu
Aleltu
37
11.7
18.8
21 .5
23.4
36.3
5b
Tiliku
Aleltu
458
73.5
117.7
134.6
147.1
228.0
6c
Jida
749
105.4
168.6
192.8
210.7
326.6
8a
Gomcro
225
43.8
70.1
80.1
87.6
135.7
9a
Robi
437
71.1
113.7
130.1
142.2
220.4
2a
Weserbi
168
35.4
56.6
64.7
70.8
109.6
12c
Duber
312
55.6
88.9
101.7
111.2
172.3
14a
Chacha
590
88.5
141 .6
162.0
177.0
274.4
10a
Jinjer
238
45.6
73.0
83.5
91.2
141.4B-67
B8 - RESERVOIR SEDIMENTATION
No quantitative analyses were carried out to determine the potential for sedimentation of the subbasin reservoirs. However, based on the results of studies carried out at similar sites (Gilgel Gibe, Amarti, etc) and from inspections carried out during the field investigation programs of the Tiliku Aleltu and Jida prefeasibility study, it was qualita tively established that sediment transport in the rivers on the high plateau area is small, and would not alter the find ings of the reconnaissance and prefeasibility studies. Quan titative studies should be carried out in the feasibility study stage.
B9 - EVALUATION OF HYDROLOGIC ANALYSES
B9.1 - General
The hydrologic analyses described in this appendix are based on the availability and quality of hydrologic data. It is
shown that there are three discharge stations and some ten rainfall stations available along the perimeter of the Aleltu drainage basin, but there are no stations located at the main rivers of the oase schemes.
In July 1983, three discharge stations were estaolished at tne Tiliku Aleltu, Jida and Gomoro rivers along the Muke Turi-Lemi Road. These stations now have one wet season of flow data available. No comparative data at other stations could be made a/ailaole for this study and these data wouldB-68
as yet be insufficient to contribute significantly to the hydrologic analyses presented herein. Future analyses and, in particular, feasibility and design level studies must incorporate these flow data if confidence in the estimate of power generating flow is to be obtained.
Therefore, the need to operate these stations to maximize data accumulation, quality and continuity is essential for future studies.
The records of the available rainfall stations are mostly short and incomplete. This largely affects the correlation analyses carried out between these stations as there are few complete and overlapping years of record available. In future studies, an effort should be undertaxen to obtain 
up-to-date records and to fill in missing months and years. The lack of data within the basin and the brevity of most of the available records affect the accuracy of the estimated rainfall distribution (isonyets) over the drainage basin; and this affects, therefore, the accuracy of the flow
calculations for individual subbasins.
The discharge records of the three stations around the Aleltu project area are of reasonable length and are reasonably complete. It was shown that there is some confidence in the accuracy of the long-term mean annual flow which can be derived from these stations. However, no satisfactory annual, seasonal or monthly relationships between flow records or unavailable rainfall data could be established. Future studies should investigate this aspect in more detail and other discharge records should De considered as well.B-69
B9.2 - Inflow Sequences
The analysis carried out to determine synthetic inflow
sequences to typify the statistics of water supply by the
subbasins was particularly based on the estimation of long
term average rainfall and the use of historical, annual and 
monthly flow variability of the Chacha discharge record.
This statistical analysis therefore adopted  the characteris tics of the Chacha record  to  be representative of the entire Aleltu Basin. However, at the Muger station, some 100 km
west, the distribution of annual and monthly discharges is different from that at the eastern side of the basin, and it appears that the variation in the Chacha record is particu larly unfavorable compared to the Muger station. It is then tentatively considered that conservative estimates of the required reservoir storage volumes to regulate the natural inflows have been obtained in this study. This is evident in comparing the results of the initial and final model runs, from which it can be seen that the dam heights in the final model runs are about 7 m higher than in the initial runs. It
is therefore believed that dam height and storage volumes are conservatively estimated.
Because the long-term firm flow available from individual subbasins is determined from rainfall isohyets, the accuracy of these isohyets is of prime importance. No rainfall stations exist within the project basins and the availability of such stations would substantially improve the accuracy of the estimated isohyets.
Evaporation losses from the subbasin reservoirs were not considered in tne layout optimization model runs. Justifica tion for this approach was based on the limited accuracy of the reservoir volume requirements, both hydrologically and topographically, and that of the estimated inflow volumes.B-68
as yet be insufficient to contribute significantly to the hydrologic analyses presented herein. Future analyses and, in particular, feasibility and design level studies must incorporate these flow data if confidence in the estimate of power generating flow is to be obtained.
Therefore, the need to operate these stations to maximize data accumulation, quality and continuity is essential for future studies.
The records of the available rainfall stations are mostly short and incomplete. This largely affects the correlation analyses carried out between these stations as there are few complete and overlapping years of record available. In future studies, an effort should be undertaken to obtain 
up-to-date records and to fill in missing months and years. The lack of data within the basin and the brevity of most of the available records affect the accuracy of the estimated rainfall distribution (isohyets) over the drainage basin; and this affects, therefore, the accuracy of the flow
calculations for individual subbasins.
The discharge records of the three stations around the Aleltu project area are of reasonable length and are reasonably complete. It was shown that there is some confidence in the accuracy of tne long-term mean annual flow which can be derived from these stations. However, no satisfactory annual, seasonal or monthly relationships between flow records or unavailable rainfall data could be established. Future studies should investigate this aspect in more detail and other discharge records should be considered as well.B-69
B9.2 - Inflow Sequences
The analysis carried out to determine synthetic inflow sequences to typify the statistics of water supply by the subbasins was particularly based on the estimation of long term average rainfall and the use of historical, annual and monthly flow variability of the Chacha discharge record.
This            statistical
analysis
therefore            adopted            the            characteris
tics       of       the       Chacha       record       to       be       representative       of       the       entire Aleltu Basin. However, at the Muger station, some 100 km
west, the distribution of annual and monthly discharges is different from that at the eastern side of the basin, and it appears that the variation in the Chacha record is particu larly unfavorable compared to the Muger station. It is then tentatively considered that conservative estimates of the required reservoir storage volumes to regulate the natural inflows have been obtained in this study. This is evident in comparing the results of the initial and final model runs, from which it can be seen that the dam heights in the final model runs are about 7 m higher than in the initial runs. It
is therefore believed that dam height and storage volumes are conservatively estimated.
Because the long-term firm flow available from individual subbasins is determined from rainfall isohyets, the accuracy of these isohyets is of prime importance. No rainfall
stations exist within the project basins and the availability of such stations would substantially improve the accuracy of the estimated isohyets.
Evaporation losses from tne subbasin reservoirs were not considered in tne layout optimization model runs. Justifica tion for this approach was based on the 1imited accuracy of the reservoir volume requirements, botn hydrologica1ly and topographically, and that of the estimated inflow volumes.B-70
Evaporation losses, however, were included for the prefeasibility estimates of the energy yield from the Tiliku Aleltu and Jida schemes. It is obvious tnat evaporation 
effects should be introduced in future layout model runs when more accurate data become available and improved analyses will be carried out.
It is noted that evapotranspiration measurements in the
Aleltu project area would greatly contribute to future evaporation analyses.
B9.3 - Flood Flows
The probability analysis carried out to determine flood flows
in the Aleltu Basin was based on a regional analysis of flow data. Daily peak discharges of stations as far away as the
Omo Basin were considered in this analysis and average rela tionships between frequency factors and the MAF were adopted. Based on the peak flows of the Chacha and Muger basins, it appears that local rainfall concentrations significantly 
affect the flood flow characteristics in that region and further analyses are required to determine more accurately such effects on the Aleltu Basin peak flows. Furthermore, it is noted that the Chacna and Muger record lengths are insuf ficient to calculate a reliable estimate of the PMF or
1:10 000-yr flood inflows. Future studies, therefore, need to be directed to establishing relationships with much longer records available outside the region considered in this analysis.W30
LEGEND
RAINFALL STATION
STREAM FLOW STATION
RAINFALx. ISOHYETS DETERMINED FROM
-  RAINFALL STATION RECORDS
-  HYDROLOGIC ATLAS OF ETHIOPIA (19^1 PERIMETER OF PROJECT DRAINAGE AREA
OMITS OF SUBBASINS
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY AlELTu HYDROELECTRIC
PLATE B-1
HYDROLOGIC DATAk«
roo
* *
* *
kilometres
LEGEND
RAINFALL STATION
STREAM FLOW STATION
RAINFALl. isohyets determined from
-  RAINFALl. station records
-  HYDROLOGIC atlas OF ETHIOPIA (1979) -------------- PERIMETER OF PROJECT DRAINAGE AREA
-------------- LIMITS OF SUBBASINS
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY
ALELTO HYDROELECTRIC PROJECT
0
HYDROLOGIC DATA BASE    ULBYEARS OF RECORD
>7
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
aaaiaai
iiaaaaai
aaaaaaai
aeaaaai
aiaaan
■■■■■II
8888881
laaaBBBI kaiaiiu
iiiaaii
■aaaiaa
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY [—’— ALELTlI HYDROELECTRIC PROJECT innrn
HYDROMETRIC RECORDING STATIONS Mill)ROI_OGY
N EXCEEDANCE CURVES
DLOGY
FIG. 3-RAINFALL/RUNOFF RELATIONSHIP OF CHACHA AND MUGER STATIONS
2
lA \ km )
iN ANNUAL FLOOD
FIG   6-TYPICAL   NON-DIMENSIONAL   FLOOD HYDROGRAPH AT CHACHA
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY
ALELTU HYDROELECTRIC project
PLATE B
HYDROLOGY STUDIES-DETAILS  HAPPENDIX C
TABLE OF CONTENTS
LIST    OF    TABLES LIST OF PLATES
Page
Cl -        GENERAL--------------------------------------------------------------------------------------------- C-
1
C2 -       DATA COLLECTION AND REVIEW------------------------------------------------------------ C-
2
C2.1 - Field Investigation Program--------------------------------------------------------------- C-
2
C2.2 - Review of Existing Data-------------------------------------------------------------------  C-
3
C3 -      GEOLOGY--------------------------------------------------------------------------------------------- C-
4
C3.1 - Regional Geology---------------------------------------------------------------------------  C-
4
C3.2 - Damsite Geology---------------------------------------------------------------------------- C-
6
C3.3 - Gorge Geology------------------------------------------------------------------------------- C-
6
C3.3.1 - General-------------------------------------------------------------------------------------- C-
6
C3.3.2 - Major Rock Units-------------------------------------------------------------------------- C-
7
C4 -      REGIONAL SEISMOLOGY----------------------------------------------------------------------------
C-15
C4.1      - General---------------------------------------------------------------------------------------
C-15
C4.2      - Earthquake          Data--------------------------------------------------------------------
C-16
C4.3      - Evaluation           Methods--------------------------------------------------------------  C-17
C4.4      - Seismicity            of Aleltu Basin------------------------------------------------------- C-19
C5 - SOILS AND MATERIALS INVESTIGATIONS --------------------------------------------  C-21
C5.1 - Test Pits and Auger Holes------------------------------------------------------------- C-21
C5.2 - Laboratory Testing----------------------------------------------------------------------- C-22
C5.3 - Test Pit Reports--------------------------------------------------------------------------- C-23
TEST PIT REPORTS PLATESAPPENDIX C
TABLE OF CONTENTS
LIST    OF    TABLES LIST OF PLATES
Cl - GENERAL
C- 1
C2 - DATA COLLECTION AND REVIEW----------------------------------------------------------------- C- 2
C2.1 - Field Investigation Program -------------------------------------------------------------- C- 2
C2.2 - Review of Existing Data------------------------------------------------------------------- C- 3
C3 -       GEOLOGY--------------------------------------------------------------------------------------------- C-       4
C3.1 - Regional Geology--------------------------------------------------------------------------- C-       4
C3.2 - Damsite Geology---------------------------------------------------------------------------- C-       6
C3.3 - Gorge Geology------------------------------------------------------------------------------- C-       6
C3.3.1 - General-------------------------------------------------------------------------------------- C-       6
C3.3.2 - Major Rock Units-------------------------------------------------------------------------- C- 7
C4 -      REGIONAL SEISMOLOGY---------------------------------------------------------------------------- C-15
C4.1 -         General-------------------------------------------------------------------------------------- C-15
C4.2 -         Earthquake       Data--------------------------------------------------------------------- C-16
C4.3 -         Evaluation         Methods--------------------------------------------------------------- C-17
C4.4 -         Seismicity         of Aleltu Basin-------------------------------------------------------- C-19
C5 - SOILS AND MATERIALS INVESTIGATIONS ------------------------------------------------- C-21
C5.1 - Test Pits and Auger Holes-------------------------------------------------------------- C-21
C5.2 - Laboratory Testing ----------------------------------------------------------------------- C-22
C5.3 - Test Pit Reports--------------------------------------------------------------------------- C-23
TEST PIT REPORTS PLATESAPPENDIX C
LIST OF TABLES
Number            Title
C. 1 Earthquake IntensitiesAPPENDIX C
LIST OF PLATES Number            Title
C-l
Geology of Tiliku Aleltu Dam Site
C-2
Geology of Jida Dam Site
C-3
Geological Section of Zega Wedem Gorge
C-4
Geological Stereonets
C-5
Seismicity of Ethiopia
C-6
Potential Jima Impervious Borrow Area
C-7
Properties of Impervious MaterialsAPPENDIX C
LIST OF TABLES
Number          Title
C.l Earthquake IntensitiesAPPENDIX C
LIST OF PLATES Number            Title
C-l
Geology of Tiliku Aleltu Dam Site
C-2                   Geology of Jida Dam Site
C-3                   Geological Section of Zega Wedem Gorge C-4                   Geological Stereonets
C-5                   Seismicity of Ethiopia
C-6                   Potential Jima Impervious Borrow Area C-7                   Properties of Impervious MaterialsAPPENDIX C
GEOLOGY, GEOTECHNICAL INVESTIGATIONS AND SEISMICITY
Cl - GENERAL
The geological and geotechnical investigation programs were carried out with the following objectives.
(a)       To determine the geological setting of the project.
(b)       To assess the foundation conditions at the two damsites selected for the first stage development in order to prepare adequate and economic design of the dams and associated conveyance structures.
(c)       To locate natural construction materials.
(d)       To identify the major rock units in the gorge and to evaluate the characteristics of each unit in order to select a technically feasible route for the penstock and power tunnel.
(e)       To locate the powerhouse on a competent bedrock foun dation in the gorge as far downstream as possible to maximize the available head and the resulting energy.
(f)        To evaluate the seismicity of tne Aleltu Basin and determine the seismic design criteria for the project structures.C-2
(g)       To produce preliminary designs of dams, rock-cut slopes, and rock support system for the tunnels and portals to a level sufficient to determine the economical and techni cal viaDility of the project at the prefeasibility 
level.
C2 - DATA COLLECTION AND REVIEW
C2.1 - Field Investigation
Program
Geological field investigations were carried out by an
integrated team of the Ethiopian Electric Light and Power
Authority and Acres International Limited (EELPA/Acres) geo
logists and geotechnical engineers during October and
November 1983. The field program was periodically reviewed
with senior staff of EELPA Planning and Programming
Department before execution.
A      helicopter      was      used      for      the      flyover      reconnaissance      of      the gorge      and      the      damsites      in      the      plateau.      Fly      tent      camps      were set     up     and     moved     to     various     places     in     the     gorge     and     plateau as the geological mapping progressed.
General geological maps and seismic data were reviewed to establish the regional geology and seismology with respect to tne project area.
Geological mapping and test pitting were carried out at tne proposed dam locations and potential borrow areas. A general geological survey of the gorge was made along the selectedC-3
penstock route. In the powerhouse area, a detailed survey 
was undertaken, including a geological mapping.
Selected soil samples were transported to laboratories in
Addis Ababa. Routine testing of soil samples was carried out
mainly in the EELPA materials testing laboratory. Laboratory 
facilities at Addis Ababa University was also used for
carrying out some specialized soil tests.
C2.2 - Review of Existing Data
Available seismological and geological maps, aerial
photographs and geological reports were reviewed. The geo
logical maps included those published by the Department of
the Interior United States Bureau of Reclamation (USBR) 1964
study of the Blue Nile River Basin,* and a more recent
Geological Map of Ethiopia published by the Ethiopian
Ministry of Mines and Energy.
Aerial       photography       at       1:10       000       scale       was       available       for       study of the area of the power facilities and damsites.
Seismological information consisted of the comprehensive work of Pierre Gouin which is described in detail in Section C4. During the field investigation program, the Ethiopian geo physical observatory was also visited to aiscuss the
seismicity of the Aleltu Basin.
«USBR, Land and Water Resources of the Blue Nile Basin, Etmopla (Seven Volumes), prepared for the Department of State Agency for International Development, 1964.C-2
(g) To produce preliminary designs of dams, rock-cut slopes, and rock support system for the tunnels and portals to a level sufficient to determine the economical and techni cal viability of the project at the prefeasibility 
level.
C2 - DATA COLLECTION AND REVIEW
C2.1 - Field Investigation
Program
Geological field investigations were carried out by an
integrated team of the Ethiopian Electric Light and Power
Authority and Acres International Limited (EELPA/Acres) geo
logists and geotechnical engineers during October and
November 1983. The field program was periodically reviewed
with senior staff of EELPA Planning and Programming
Department before execution.
A      helicopter      was      used      for      the      flyover      reconnaissance      of      the gorge      and      the      damsites      in      the      plateau.      Fly      tent      camps      were set     up     and     moved     to     various     places     in     the     gorge     and     plateau as the geological mapping progressed.
General geological maps and seismic data were reviewed to establish the regional geology and seismology with respect to the project area.
Geological mapping and test pitting were carried out at the proposed dam locations and potential borrow areas. a general geological survey of the gorge was made along tne selectedC-3
penstock route. In the powerhouse area, a detailed survey 
was undertaken, including a geological mapping.
Selected soil samples were transported to laboratories in
Addis Ababa. Routine testing of soil samples was carried out
mainly in the EELPA materials testing laboratory. Laboratory 
facilities at Addis Ababa University was also used for
carrying out some specialized soil tests.
C2.2 - Review of Existing Data
Available seismological and geological maps, aerial
photographs and geological reports were reviewed. The geo
logical maps included those published by the Department of
the Interior United States Bureau of Reclamation (USBR) 1964
study of the Blue Nile River Basin,* and a more recent
Geological Map of Ethiopia published by the Ethiopian
Ministry of Mines and Energy.
Aerial       photography       at       1:10       000       scale       was       available       for       study of the area of the power facilities and damsites.
Seismological information consisted of the comprehensive work of Pierre Gouin which is described in detail in Section C4. During the field investigation program, the Ethiopian geo physical observatory was also visited to aiscuss the
seismicity of the Aleltu Basin.
*USBR, Land ana Water Resources of the Blue Nile Basin, Ethiopia (Seven Volumes), prepared for the Deparr.mpnr of State Agency for International Development, 1964.C-4
Following the review of all documents, a geological mapping and a test pit exploration program were carried out.
C3 - GEOLOGY
C3.1 - Regional Geology
Ethiopia lies along the main oceanic boundary between two major tectonic plates, namely, the African and Arabian
plates; and also straddles the East African Rift System.
The oldest rocks in Ethiopia, with ages over 600 million
years, are the sheared and folded Precambrian metamorphic and granitic rocks, referred to as the crystalline basement
complex. Most of the Precambrian rocks are relatively imper meable, and have been subjected to several orogenic episodes since their formation. This process, combined witn the rift
ing associated with the development of the Ethiopian Rift Valley, has resulted in considerable fracturing and
shattering.
At the end of the Precambrian times, uplift occurred which was followed by a long period of erosion. Any sediments wnich were deposited during the Paleozoic interval, which lasted some 375 million years, have been largely removed by erosion. Such a long period of erosion and denudation left
the earth's surface of East Africa and Etniopia completely peneplained.
Crustal motion started in the beginning of Mesozoic period about 225 million years ago. During the late Triassic and early Jurassic periods, a regional epeirogenic sinking of theC-5
crust commenced causing a progressive transgression of the
ocean from the southeast, that is, from the Indian Ocean
coast of present Somalia in the general direction of Lake
Tana in northwest Ethiopia. This downward crustal movement,
concomitant with a sedimentation process, started a cycle of
marine transgression and recession of the Mesozoic sea.
Within this large epicontinental sea, extensive layers of
sediments were deposited to form hundreds of metres of rocks 
consisting of sandstone, shale, gypsum, limestone and otner
varieties of bedded rocks. The crustal movement was reversed
into a upward motion during the late Jurassic period which
brought the crust’s surface up to sea level by the end of the
Mesozoic period, 65 million years ago, and finally uplifted
it through intermittent but progressive phases throughout
Tertiary and Quaternary times to the present level of more
than 3,000 m above sea level.
Extensive        fracturing        occurred        within        the        earth's        crust        by        the doming process due to progressive uplift early in the
Cenozoic period (the earliest rocks of which are dated
65 million years), although major displacement along the fault systems did not occur until later in the Tertiary 
period. Faulting was accompanied by widespread volcanic activity and the two processes, which are partly related, have largely determined the form of the landscape in the western naif of Ethiopia and in the Afar depression. The outpouring of vast quantities of basaltic lava over the western half of the country was accompanied by, and alter nated with the eruption of large amounts of ash and coarser fragmental material, forming the Trap Series. More recent volcanism is associated with the development of the Rift System, activity being concentrated within tms structure and along tne edge of the adjoining plateau.C-6
C3.2 - Damsite Geology
Geological mapping was carried out for the prefeasibility damsites. These mappings are based on aerial photography, existing mapping and ground level and aerial reconnaissances. The geological mapping of the damsites is shown on Plates C-l and C-2.
C3.3 - Gorge Geology
C3.3.1 - General
Site investigations along the power tunnel and pen stock alignment consisted of geologic mapping of bedrock outcrops as close to the alignment as possi- ble.        The results of the geological mapping are summarized as a geological section of the gorge and shown on Plate C-3.
The outcrops found mainly along the Agat at lower elevations and along the gullies and cliff faces at upper elevations were considered typical for the gorge face. All mapped outcrops on the gorge face were connected by a survey traverse. The field notes collected on outcrop samples include rock type, color, grain size, strength, degree of weathering, jointing and rock mass fabric. Stereonets showing the distri bution of jointing were plotted and contoured as shown on Plate C-4.
The elevations and thickness of various units shown are approximate only and applicable only close to the alignment. Lower rock units in the gorge were basedC-7
on mapping the outcrops along the Agat River and projected to the proposed alignment. Some generaliza tions and approximations were found necessary because of almost near vertical inaccessible outcrops of
stronger units and lack of outcrops of extensively weathered weaker units.
C3.3.2 - Major Rock Units
Surface geological mapping indicates 14 major rock units along the proposed power tunnel and penstock alignment, and a brief description of each unit
starting from the bottom of the gorge is given below.
Shale with Lenses 
of Sandstone___________
(From el 1,511 to 1,527)
The shale is generally of variegated type with
colors grading from grayish to pinkish, fine to very fine grained, very weak to weak at the surface, very thin to thinly bedded, moderately weathered to
highly weathered with lenses of moderately weak to moderately strong sandstone. Beddings are extremely continuous to greater than 2 m with evidence of pronounced cross—bedding in places. Seepage was observed along the contact Detween sandstone and shale at river level.
Sandstone with Interbeds 
of Snale and Mudstone
(From el 1,527 to 1,553)
The sandstone is interbedded witn thin to medium beds of shale and mudstone, generally gray in color,C-6
C 3.2 - Damsite Geology
Geological mapping was carried out for the prefeasibility damsites. These mappings are based on aerial photography, existing mapping and ground level and aerial reconnaissances. The geological mapping of the damsites is shown on Plates C-l and C-2.
C3.3 - Gorge Geology
C3.3.1 - General
Site investigations along the power tunnel and pen stock alignment consisted of geologic mapping of bedrock outcrops as close to the alignment as possi- ble.        The results of the geological mapping are summarized as a geological section of the gorge and shown on Plate C-3.
The outcrops found mainly along the Agat at lower elevations and along the gullies and cliff faces at upper elevations were considered typical for the gorge face. All mapped outcrops on the gorge face were connected by a survey traverse. The field notes collected on outcrop samples include rock type, color, grain size, strengtn, degree of weathering, jointing and rock mass fabric. Stereonets showing the distri bution of jointing were plotted and contoured as shown on Plate C-4.
The elevations and thickness of various units shown are approximate only and applicable only close to the alignment. Lower rock units in the gorge were basedC-7
on mapping the outcrops along the Agat River and projected to the proposed alignment. Some generaliza tions and approximations were found necessary because of almost near vertical inaccessible outcrops of
stronger units and lack of outcrops of extensively weathered weaker units.
C3.3.2 - Major Rock Units
Surface geological mapping indicates 14 major rock units along the proposed power tunnel and penstock alignment, and a brief description of each unit
starting from the bottom of the gorge is given below.
Shale with Lenses 
of Sandstone__________
(From el 1,511 to 1,527)
The shale is generally of variegated type with
colors grading from grayish to pinkish, fine to very fine grained, very weak to weak at the surface, very thin to thinly bedded, moderately weathered to
highly weathered with lenses of moderately weak to moderately strong sandstone. Beddings are extremely continuous to greater than 2 m with evidence of pronounced cross—bedding in places. Seepage was observed along tne contact between sandstone and shale at river level.
Sandstone with Interbeds 
of Shale and Mudstone
(From el 1,527 to 1,553)
The sandstone is interbedded with thin to medium beds of shale and mudstone, generally gray in color,C-8
fine to very fine grained, moderately weak to moderately strong, slight to moderately weathered. Beddings in general are extremely continuous with evidence of cross-bedding in places. Thin localized places of lignite were also present and these beds are not as continuous as the sandstone beds. Joint ing is well developed and generally conforms to the regional trend shown on Plate C-3. Spacing of joints varies from 0.5 to greater than 1.0 m.
Shaly Limestone
with Interbeds of
Mudstone and Shale
(From el 1,553 to 1,613)
The sandy limestone is interbedded with medium to thick interbeds of calcareous mudstone, gypsum and carbonaceous shale, light gray to whitish in color, fossiliferous toward top, strong to very strong, faulted with fault displacements varying from 2 to 40 cm. The sandy limestone is fresh to faintly weathered whereas the mudstone shale is moderately weathered. The strength of shale and mudstone interbeds is moderately weak. The gypsum encoun tered at lower elevations was more of massive and amorphous type. Thin sheets of well developed and crystallized gypsum were observed at higher eleva tions. Large solution cavities were observed along the contact of gypsum and limestone, and the natural stream in many places passes through these
cavities.
Sandstone
(From el 1,613 to 1,989)
The sandstone unit is the thickest of all units mapped in the gorge and is about 376 m thick along C-9
the proposed power tunnel and penstock alignment. Most of the slope failures and slope instabilities
in the gorge were related to this sandstone unit. The sandstone is light gray to white at bottom and grading to pinkish toward top due to oxidation, fine to medium grained with occasional gritty coarse layers of mostly quartz, moderately weak to weak, very thickly bedded with evidence of cross-bedding, poorly cemented, slight to moderately weathered. The joints are widely spaced and extremely continuous to greater than 2 m.
Lower Basalt
(From el 1,989 to 2,093)
The lower basalt consists of two flow units and the contact between lower flow unit and sandstone appears to be tight and no apparent weakness is observed. Both flow units of basalt are dark bluish-gray in color, fine grained, and strong to very strong, blocky toward top, vesicular and scoriaceous in places. Jointing is mostly columnar and close- to medium-spaced. Subhorizontal joints with waviness were observed at the upper portion of lower flow unit. The amplitude of tne waviness is up to 2 m in places and the waviness is probably due to variation in strength of poorly cemented underlying sandstone.
The contact between flow units about 2 m thick, moderately weak to weak, very close to closely jointed, vesicular toward top witn inclusions of calcite and thin beds of vitrified wood.C-10
Lower Lacustrine
(From el 2,093 to 2,137)
This unit is very thin compared to other rock units in the gorge and mostly covered by talus and culti vated field. No significant exposures were encoun tered around the penstock route. Scattered odd outcrops of silicified mudstone were observed at contact with lower basalt. Exposures elsewhere on the other side of Agat at the same level indicate strong welded tuff mixed with vesicular basalt.
Agglomerate
(From el 2,137 to 2,275)
The agglomerate consists of three massive units and is of cliff-forming character. It is light gray to light brown in color, composed of an average 40% cobbles with sizes ranging from 1 to 70 cm, strong to very strong, faintly weathered, very widely jointed and thickly bedded. The contact Detween flow units is about 1-m thick and consists of
moderately weak to weax tuffaceous ash.
Middle Basalt
( From el 2,27 5 to 2,307)
The middle basalt is dark gray in color, fine grained, strong to very strong, columnar jointed with an average block size of 20 cm, faintly weathered. This unit does not appear to oe continuous laterally.C-l 1
Upper Lacustrine
(From el 2,307 to 2,389)
The upper lacustrine unit is probably deposited in a shallow deltaic environment and a typical outcrop, from top to bottom, consists of
-    light gray ash tuff, massive, moderately strong, poorly cemented and friable, slightly weathered
-   light gray sandy siltstone, fine to medium
grained, tnin to medium bedded with laminations of shale, moderately weak, moderately weathered
-    light gray mudstone, very weak and crumbling, moderately weathered
-   brownish shale, very thinly laminated, weak, moderately weathered
-    light gray sandy siltstone, fine to medium
grained, moderately weak, moderately weathered
-    light gray to pinkish silicified mudstone, moderately strong, slightly weathered
-   middle basalt.
Exposures elsewhere near Debre Libanos church on the otner side of Agat at the same level indicate the presence of carbonaceous shale and lignite.C-12
Upper Basalt - First
and Second Flow Units
(From el 2,389 to 2,485)
The first unit is about 62 m thick and the second 
unit is about 34 m thick. Both units of basalt are
dark gray, fine grained, slightly vesicular, strong 
to very strong, fresh to faintly weathered, columnar
jointed with block sizes ranging from 30 to 50 cm. 
The vesicles in the first flow unit are generally 
filled with secondary mineralization.
The contact between the lower lacustrine and first
flow unit is about 2 m thick and, from top to 
bottom, consists of
-      brown      grading      to      dark      gray      ash      tuff,      moderately strong,       highly       weathered       and       altered       by       contact metamorphism
- dark gray siltstone with dark strains, moderately weak, highly weathered
- yellowish ash tuff, moderately strong, moderately weathered.
The contact between the two flow units of basalt is about 4.5 m tnick and consists of highly weathered and generally weak to very weak basalt with closely spaced columnar joints. The upper 2.5 m of contact is light to reddish brown in color and probably nardened by contact metamorphism.C-13
Basic Breccia
and Pyroclastics
(From el 2,485 to 2,515)
The basic breccia and pyroclastics are considered as
part of the upper basalt and referred to as third 
flow unit. A typical outcrop of this unit indicates
pyroclastic overlying basic breccia. The basic
breccia consists of the mixture of rough "aa" sur
face and other basaltic angular to subangular frag
ments from 1 mm to 6 cm, weak to moderately weak, 
moderately weathered with inclusions of fossilwood.
The       fragments       are       massive       and       vesicular       and       probably constitute about 20% Dy volume.
The pyroclastic is light gray to yellowish lapillus ash tuff grading to ash tuff with depth, very light
in weight, fine to medium grained with inclusions of volcanic glass in places, generally weak with moderately strong intercalations, thin to medium bedded and medium jointed, beds tilted locally and extremely continuous to greater than 2 m. The upper portion of this unit is locally interbedded with 
thin to medium beds of lignite.
The contact at the bottom between the breccia and the underlying basalt is very rough because of "aa" surface and generally is tight without any paleosol. The contact zone consists of highly weathered zone of about 3 m thick and part of it is hardened by contact metamorpnism.
The contact between the pyroclastic and the over- lying basalt is about 5 m thick. The bottom 4 m is moderately weathered to highly weathered, and partC-12
Upper Basalt - First
and Second Flow Units
(From el 2,389 to 2,485)
The first unit is about 62 m thick and the second unit is about 34 m thick. Both units of basalt are dark gray, fine grained, slightly vesicular, strong to very strong, fresh to faintly weathered, columnar jointed with block sizes ranging from 30 to 50 cm. The vesicles in the first flow unit are generally filled with secondary mineralization.
The contact between the lower lacustrine and first flow unit is about 2 m thick and, from top to bottom, consists of
- brown grading to dark gray ash tuff,
strong,        highly weathered and altered metamorph ism
- dark gray siltstone with dark strains, moderately weaK, highly weathered
- yellowish ash tuff, moderately strong, moderately weathered.
The contact between the two flow units of basalt is about 4.5 m thick and consists of highly weathered and generally weak to very weak basalt with closely spaced columnar joints. The upper 2.5 m of contact is light to reddish brown in color and probably nardened by contact metamorphism.
moderately
by contactC-13
Basic Breccia
and Pyroclastics
(From el 2,485 to 2,515)
The basic breccia and pyroclastics are considered as
part of the upper basalt and referred to as third 
flow unit. A typical outcrop of this unit indicates
pyroclastic overlying basic breccia. The basic
breccia consists of the mixture of rough "aa" sur
face and other basaltic angular to subangular frag
ments from 1 mm to 6 cm, weak to moderately weak, 
moderately weathered with inclusions of fossilwood.
The       fragments       are       massive       and       vesicular       and       probably constitute about 20% by volume.
The pyroclastic is light gray to yellowish lapillus ash tuff grading to ash tuff with depth, very light
in weight, fine to medium grained with inclusions of volcanic glass in places, generally weak with moderately strong intercalations, thin to medium bedded and medium jointed, beds tilted locally and extremely continuous to greater than 2 m. The upper portion of this unit is locally interbedded with 
thin to medium beds of lignite.
The contact at the bottom between the breccia and tne underlying basalt is very rough because of "aa" surface and generally is tight without any paleosol. The contact zone consists of highly weathered zone of about 3 m thick and part of it is nardened by contact metamorphism.
Tne contact between the pyroclastic and the over- lying basalt is aDout 5 m thick. The bottom 4 m is moderately weathered to highly weathered, and partC-14
of it is hardened by contact metamorphism. The top 
1 m is part of the overlying basalt and is highly weathered to weak. Evidence of leaching and solu tion deposits on the surface were observed in both rock types on the exposed face.
Upper Basalt -
Fourth Flow Unit
(From el 2,515 to 2,541)
The fourth flow unit of basalt is dark gray in 
color, fine grained, slightly vesicular at the
bottom becoming highly vesicular toward the top with openings up to 3 cm wide, very strong, fresh to faintly weathered, columnar jointed with block sizes ranging from 10 to 100 cm. This unit in highly weathered form is exposed on the low-lying areas of the plateau and the color of these exposures is generally white possibly due to the leaching of
mafic minerals.
The contact between the fourth flow unit of basalt and the overlying pyroclastic appears to be grada tional with a thick highly weathered zone and was not easily recognizable in the field.
Pyroclastic
(From el 2,541 to 2,561)
The pyroclastic between the fourth and fifth flow units of basalt is an interoedded lapillus tuff, lapillus ash tuff and ash tuff, moderately weak to 
moderately strong, slightly weathered, medium bedded. This unit in low-lying areas around Agat is eroded and observable along the edges of trie plateau and near prominent hills such as the Mite Hill.C-15
Upper Basalt -
Fifth Flow Unit
(From el 2,561 to 2,600)
The top of the fifth flow unit of basalt forms the surface of the plateau and is dark gray in color, fine grained, very strong, fresh to faintly 
weathered, columnar jointed with an average block size of about 15 cm.
C4 - REGIONAL SEISMOLOGY
C4.1 - General
Ethiopia has experienced the effects of earthquakes and volcanic activity throughout its history due to its geo graphic location in the vicinity of two seismically active tectonic features. These are the major tectonic plate boun dary which divides the continental Africa from the Arabian peninsula and tne major break in the earth's crust due to the East African rift systems. Seismic activity in Ethiopia, as it relates to the Aleltu project, is shown on Plate C-5, Figures 1 and 2.
The methodology used and the results pertaining to the evaluation of seismicity of tne Aleltu Basin are described in the following sections.C-16
Pierre Gouin made a comprehensive study of the seismicity of Ethiopia* by compiling, in a logical manner, the earthquake records dating back to 1400 A.D. This study was, therefore, essentially an analysis of historical data.
C4.2 - Earthquake Data
The data file for the 575 years of earthquake history, on the whole, is neither sufficiently accurate nor numerically complete enough to be subjected to statistical analysis. It
was, therefore, necessary to select within that historical
period a time interval which could be considered as the best representative sample of the current seismic activity. The
more modern events confirmed by instrumental recordings from either local or foreign seismic stations during the period 
from 1875 to 1974 were- considered scientifically reliable and were used as the basis for the evaluation of seismicity of Ethiopia. Plate C-5, Figure 3, snows the location of all
seismic events that can be assigned reliable geographic coor dinates with enough accuracy. The estimated magnitudes of all the seismic events are shown on Plate C-5, Figure 4. The extent of the Aleltu Basin is also shown on these location maps. The Aleltu Basin is along the margin of the Rift System where largest number of epicenters and volcanoes are located.
•Gouin, P., "Eartnquake History Africa," Publication No. 118e, Research Centre, Canada, 1977.
of     Ethiopia     and     the     Horn     of International DevelopmentC-17
C4.3 - Evaluation Methods
(a)      Summary
The seismicity distribution over the country was obtained by summing up and contouring the amplitudes experienced at a series of selected reference points distributed over Ethiopia. A total of 650 reference points formed the grid. For each point on the grid, the amplitudes experienced from each seismic event regis tered for the period from 1875 to 1974 were computed in terms of intensities and ground accelerations. Inten sities are given in modified Mercalli (MM) units and the ground accelerations in percentage of the standard gra vitational acceleration, g. The predicted acceleration 
and intensity values were plotted on the base map and then contoured as shown on Plate C-5, Figures 6 and 7.
(b)      Attenuation
Computation of intensity from independent seismic events requires attenuation characteristics of the site, i.e., 
how the intensity of the resulting ground motion decreases with distance from the origin of an earth
quake. No quantitative measurements of ground motion in Ethiopia are available to derive an attenuation rela tionship from actual measurements in the region. There fore, the rates of attenuation were obtained by deriving quasi-equivalent geological and crustal conditions. The dominant crustal structures in Ethiopia are the rift and 
the plateau. A suitable analogy of these two crustal structures occurs on the North American Continent— California on West Coast can be approximated to the tectonically disturbed rift regions of Ethiopia; andC-16
Pierre Gouin made a comprehensive study of tne seismicity of Ethiopia’ by compiling, in a logical manner, the earthquake records dating back to 1400 A.D. This study was, therefore, essentially an analysis of historical data.
C4.2 - Earthquake Data
The daca file for the 575 years of earthquake history, on the whole, is neither sufficiently accurate nor numerically complete enougn to be subjected to statistical analysis. It
was, therefore, necessary to select within that historical
period a time interval which could be considered as the best representative sample of the current seismic activity. The
more modern events confirmed by instrumental recordings from either local or foreign seismic stations during the period 
from 1875 to 1974 were- considered scientifically reliable and were used as the basis for the evaluation of seismicity of Ethiopia. Plate C-5, Figure 3, shows the location of all
seismic events that can be assigned reliable geographic coor dinates with enough accuracy. The estimated magnitudes of all the seismic events are shown on Plate C-5, Figure 4. The extent of the Aleltu Basin is also shown on these location maps. The Aleltu Basin is along the margin of the Rift System where largest number of epicenters and volcanoes are located.
Gouin,  P.,  "Earthquake History Africa," Publication  No.  118e, Research Centre, Canada, 1977.
of     Ethiopia     and     tne     Horn     of International DevelopmentC-17
C4.3 - Evaluation Methods
(a)       Summary
The seismicity distribution over the country was
obtained by summing up and contouring the amplitudes experienced at a series of selected reference points distributed over Ethiopia. A total of 650 reference
points formed the grid. For each point on the grid, the amplitudes experienced from each seismic event regis tered for the period from 1875 to 1974 were computed in terms of intensities and ground accelerations. Inten sities are given in modified Mercalli (MM) units and the ground accelerations in percentage of the standard gra vitational acceleration, g. The predicted acceleration 
and intensity values were plotted on the base map and then contoured as shown on Plate C-5, Figures 6 and 7.
(b)       Attenuation
Computation of intensity from independent seismic events requires attenuation characteristics of the site, i.e., 
how the intensity of the resulting ground motion decreases with distance from the origin of an earth-
quaxe. No quantitative measurements of ground motion in Ethiopia are availaDle to derive an attenuation rela tionship from actual measurements in the region. There fore, tne rates of attenuation were obtained by deriving quasi-equivalent geological and crustal conditions. The dominant crustal structures in Etniopia are tne rift and the plateau. A suitaole analogy of these two crustal structures occurs on the North American Continent— California on West Coast can be approximated to the tectonically disturbed rift regions of Ethiopia; andC-18
Eastern Canada to the bedding conditions under the plateau. The adopted attenuation curves for earthquakes in Ethiopia are shown on Plate C-5, Figure 5.
(c)       Acceleration and
Intensity Maps
The instrumental information from the data file provided magnitudes of earthquakes and the macroseismic evidence provided some of the intensities. The reciprocal conversion of magnitude and intensities, and the compu tation of ground accelerations make use of the following relations.
Acc = 3 
(I-j-9.66 + 1.38 M) + 4.5 for M>5
Acc
0.69
1.64 M
e_______
1.1    e
1.1 M
for M<5
i =3 Uog10 Acc + 1*5)
where
Acc      =      ground      acceleration      in      percent      of      gravity M     = magnitude of earthquake in MM units
I       = intensity
I7 = intensity produced Dy an earthquake of magnitude 7
To determine the return period or tne rate of recurrence associated with the predicted acceleration levels for each reference point, the method of extreme valueC-19
statistics was used. This method was successfully 
applied to the analysis of seismic hazards in Canada by 
Milne and Davenport in 1969. These statistics make use
of only the yearly peak amplitudes experienced at each 
reference grid point. The reason for using only one
value over a determined period of time is to filter out
the effects of foreshocks and aftershocks. In the
original computations, return periods ranging from 3 to
1,000 years have been evaluated.
Considering        the        length        of        the        sampling        interval        a        100-yr return period is considered reliable, and beyond
100 years, the maximum intensities have been checked against the data of a 575-yr data file. The predicted ground acceleration and intensity maps of Ethiopia based on a 100-yr return period are shown on Plate C-5, Figures 6 and 7.
The predicted ground acceleration and intensity for
three towns adjacent to Aleltu Basin for 100-, 200- and 300-yr return periods are summarized in Table C.l.
C4.4 - Seismicity of Aleltu Basin
The Aleltu Basin is bounded between latitudes of 9.25° and 10.00°, and longitudes of 38.75° and 39.50°. This region is along the Western Plateau and close to the "Y" intersection 
of the Red Sea, Gulf of Aden and the Etniopian rifts. The predicted ground acceleration based on a 100-yr recurrence period from Plate C-5, Figure 6, is between 5 and 10% and the intensity from Plate C-5, Figure 7, is VII to VIII. Based on averaging the values reported for the three nearby towns
Addis Ababa, Debre Bernan and Chancno——the acceleration is 10.2% for a return period of 200 years and 15.3% for a returnC-18
Eastern Canada to the bedding conditions under the plateau. The adopted attenuation curves for earthquakes in Ethiopia are shown on Plate C-5, Figure 5.
(c)       Acceleration and 
Intensity Maps
The instrumental information from the data file provided magnitudes of earthquakes and the macroseismic evidence provided some of the intensities. The reciprocal conversion of magnitude and intensities, and the compu tation of ground accelerations make use of the following relations.
Acc = 3 log1Q
 ( I -9.66-t-l. 38 M) + 4.5 for M>5
?
Acc
0.69
1.64 M
e_______
1.1    e
1.1 M
for M<5
I =3 (log^g Acc + 1.5)
where
Acc      =      ground      acceleration      in      percent      of      gravity M     = magnitude of earthquake in MM units
I       = intensity
I7      =      intensity      produced      Dy      an      earthquake      of magnitude 7
To determine the return period or the rate of recurrence associated with tne predicted acceleration levels for each reference point, the method of extreme valueC-19
statistics was used. This method was successfully 
applied to the analysis of seismic hazards in Canada by 
Milne and Davenport in 1969. These statistics make use
of only the yearly peak amplitudes experienced at each 
reference grid point. The reason for using only one
value over a determined period of time is to filter out
the effects of foreshocks and aftershocks. In the
original computations, return periods ranging from 3 to 
1,000 years have been evaluated.
Considering        the        length        of        the        sampling        interval        a        100-yr return period is considered reliable, and beyond
100 years, the maximum intensities have been checked against the data of a 575-yr data file. The predicted ground acceleration and intensity maps of Ethiopia based on a 100-yr return period are shown on Plate C-5, Figures 6 and 7.
The predicted ground acceleration and intensity for three towns adjacent to Aleltu Basin for 100-, 200- and 300-yr return periods are summarized in Table C.l.
C4.4 - Seismicity of Aleltu Basin
The Aleltu Basin is bounded between latitudes of 9.25° and 10.00°, and longitudes of 38.75° and 39.50°. This region is along the Western Plateau and close to the "Y" intersection 
of the Red Sea, Gulf of Aden and the Etniopian rifts. The predicted ground acceleration based on a 100-yr recurrence period from Plate C-5, Figure 6, is between 5 and 10% and the intensity from Plate C—5, Figure 7, is VII to VIII. Based on averaging the values reported for the three nearDy towns
Addis Ababa, Debre Berhan and Chancho——the acceleration is 10.2% for a return period of 200 years and 15.3% for a returnC-20
TABLE C.1
EARTHQUAKE INTENSITIES Coordinates (° )
Return Period (yr)
100         200
300
Location
North     East
I*    A**   I*       A**    I*     A*w
Addis Ababa
9.00
38.77
VII
6.9
VIII
13.3
VIII
20.0
Debre Berhan
9.30
39.30
VII
5.3
VIII
9.7
VIII
14.0
Chancho
9.32
38.73
VII
4.7
VII
8.5
VIII
12.0
Average
9.15 to
38.75 to
VII
5.6
VII to VIII
10.2
VIII
15.3
estimated
10.00
39.50
for Aleltu
♦ I = MM intensities
* A = Ground acceleration as percent of standard
W
gravitational acceleration
gC-21
period of 300 years. The corresponding intensities of earthquake vary from MM index VII to VIII or a Richter magnitude of 6. A 300-yr life span appears to be reasonable for the major dam and other water conveyance structures of Aleltu. Therefore, a design acceleration of 15% correspond ing to an event with a return period of 300 years was considered appropriate to the present level of study.
C5 - SOILS AND MATERIALS
INVESTIGATIONS
C5.1 - Test Pits and 
Auger Holes
To determine the nature, depth and extent of overburden, a total of 14 test pits were excavated at tne damsites: 5 at Tiliku Aleltu, 6 at Jida and 3 at Tinishu Aleltu (see
Plates C-l, C-2 and C-6). It is noted that test pits were excavated at the Tinishu Aleltu damsite wnile reconnaissance studies continued. Eventually, as reported in Section 2, the Tinishu Aleltu scheme was eventually eliminated. In addi tion, a total of 6 test pits and 3 auger holes were completed in the potential Jima impervious borrow area, as shown on Plate C-6. The test pits were manually excavated to a depth of 3 to 4 m with shovel and picks. The nand auger holes were drilled to a maximum depth of 3 m. In many instances, hand auger holes were drilled at the bottom of the test pits to extend the depth of investigation.C-22
All the test pits were excavated without any snoring or
temporary supports. All test pits were left open for more
than a month and groundwater levels were monitored. Tension 
cracks and minor caving of walls were observed in general in 
tne test pits at impervious borrow area.
Pocket penetrometer readings were taken at regular intervals. 
As the materials encountered in impervious borrow areas were
generally homogeneous without any lenses or stratification, 
sampling was confined mostly to bulk channel samples. 
Description of the soil and the types of samples taken are
given in test pit reports, Section C5.3.
C5.2 - Laporatory Testing
Materials testing facilities at EELPA and University of Addis
Aoaba were utilized for performing the limited numoer of
routine and specialized strength and consolidation tests.
The      details      of      tests      carried      out      on      selected      samples      from      the damsite and impervious borrow area are as follows.
Type of Tests
(a) Damsite
Specific gravity
Natural moisture content tests Atterberg consistency limit tests Grain size analyses
(b) Impervious Borrow Area
Natural moisture content tests Atterberg consistency limit testsC-23
Grain size analyses
Standard Proctor compaction tests
Undrained strength tests
Swelling pressure tests
Consolidation tests
Direct shear tests
All tests were performed in accordance with ASTM Standards. The results of all tests performed on impervious material are summarized on Plate C-7.
C5.3 - Test Pit Reports Definitions
Location        and elevation
Datum
Depth
Sample number
Elevation and location of test pits
and boreholes were determined by 
precise leveling and horizontal
distance measurement. All measure
ments are based on control points
established at Tiliku Aleltu and 
Robi Jida damsites.
All       elevations       refer       to       mean       sea level (MSL) as datum.
All      depths      are      given      in      metres, measured from the ground surface.
Samples are numbered numerically in tne order in wmch they were obtained, except where noted.C-22
All the test pits were excavated without any shoring or temporary supports. All test pits were left open for more
than a month and groundwater levels were monitored. Tension cracks and minor caving of walls were observed in general in the test pits at impervious borrow area.
Pocket penetrometer readings were taken at regular intervals. As the materials encountered in impervious borrow areas were generally homogeneous without any lenses or stratification, sampling was confined mostly to bulk channel samples. Description of the soil and the types of samples taken are given in test pit reports, Section C5.3.
C5.2 - Laboratory Testing
Materials testing facilities at EELPA and University of Addis Ababa were utilized for performing the limited numDer of routine and specialized strength and consolidation tests.
The details of tests carried out on selected samples from the damsite and           impervious         borrow area are as follows.
Type of Tests
(a) Damsite
Specific gravity
Natural moisture content tests Atterberg consistency limit tests Grain size analyses
(p) Impervious Borrow Area
Natural moisture content tests Atterberg consistency limit testsGrain size analyses
Standard Proctor compaction tests
Undrained strength tests
Swelling pressure tests
Consolidation tests
Direct shear tests
All tests were performed in accordance with ASTM Standards. The results of all tests performed on impervious material are summarized on Plate C-7.
C5.3 - Test Pit Reports Definitions
Location and elevation
Datum
Depth
Sample number
Elevation and location of test pits
and boreholes were determined by 
precise leveling and horizontal
distance measurement. All measure
ments are based on control points established at Tiliku Aleltu and 
Robi Jida damsites.
All   elevations            refer       to mean sea level (MSL) as   datum.
All   depths are           given       in metres, measured from tne ground surface.
Samples are numbered numerically in tne order in which they were obtained, except where noted.C-24
Sample      type
Sample     size
Sample retained
Soil type
Indicated by two letters, the first
of these describes the sampling method and the second, the shipping container.
Dimension in millimetres and refers to the nominal diameter of the sample.
Indicates the length in millimetres of sample retained in the sampler. If no value is indicated, no recovery of sample is assumed.
Approximate composition of soil is expressed according to the following weight-percent relationship.
Silt and clay
Silty clay
Clay with some
silt
Clay witn trace
45 to 50% silt 45   to    50%  clay 25    to   45%  silt 55   to    75%  clay 10   to    25%  silt 75   to    90%  clay
<10%      silt
of silt
Clays and Silts
Consistency
Very soft
Soft
Medium soft
>90% clay
Consistency 
of
clays and silts
Unconfined
Compressive
Strength
(xg.m/cm )
<0.25
0.25 to 0.50
0.50 to 1.00
2C-25
Consistency of
clays         and         silts (cont)
Soil plasticity
Clays         and         Silts Consistency
Stiff
Very stiff Hard
Description
Unconf        ined Compressive Strength 
2
(kg.m/cm )
1.00 to 2.00
2.00 to 4.00 
>4.00
Plasticity Index (PI)
Nonplastic
0 to
4
Slightly plastic
4 to
15
Medium plastic
15 to
30
Hignly plastic
>30
Grain size
Description
distribution
Particle Size
(mm)
Boulder
305.000
or
more
Cobble
76.000
to
305.000
Coarse gravel
19.000
to
76.000
Fine gravel
4.760
to
19.000
Coarse sand
2.000
to
4.760
Medium sand
0.420
to
2.000
Fine sand
0.074
to
0.420
Silts and clays
<0.074
Grain size of rocks
Description
Very coarse grained
Coarse grained
Grain Size
(mm)
>60.000
2.000 to 60.000C-24
Sample type
Sample size
Sample retained
Soil type
Indicated by two letters, the first
of these describes the sampling method and the second, the shipping container.
Dimension in millimetres and refers to the nominal diameter of the sample.
Indicates the length in millimetres of sample retained in the sampler. If no value is indicated, no recovery of sample is assumed.
Approximate composition of soil is expressed according to the following weight-percent relationship.
Consistency           of clays and silts
Silt and clay
Silty clay
Clay with some
silt
Clay with trace
of silt
Clays       and       Silts Consistency
Very soft Soft Medium soft
45 to 50% silt 45    to   50%  clay 25    to   45%  silt 55   to    75%  clay 10   to    25%  silt
75   to    90%  clay <10%      silt
>9G% clay
Unconfined Compressive Strength
2
(kg.m/cm )
<0. 25
0.25 to 0.50 0.50 to 1.00C-25
Consistency of
clays and silts
Clays       and 
Silts
(cont)
Consistency
Unconfined Compressive Strength 
Soil plasticity
Grain size distribution
Grain size of rocks
Stiff
Very stiff Hard
Description
Nonplastic Slightly plastic Medium plastic Highly plastic
Description
Boulder Cobble Coarse gravel
Fine gravel Coarse sand
Medium sand Fine sand
Silts and clays Description
Very coarse grained
Coarse grained
2
(kg.m/cm )
1.00 to 2.00
2.00 to 4.00
>4.00
Plasticity
Index (PI)
0 to 4
4 to 15
15 to 30
>30
Particle Size
(mm)
305.000 or more
76.000 to 305.000
19.000 to 76.000
4.760 to 19.000
2.000 to 
0.420 to 
0.074 to 
<0.074
Grain Size
(mm)
>60.000
2.000 to 60.000
4.760
2.000
0.420Grain       size       of      rocks (cont)
C-26 Description
Grain Size (mm)
Medium grained Fine grained 
Very fin
e
0.060 to 2.000
0.002 to 0.060 
<0.002
grain
ed
Discontinuity 
characteristics
Spacing 
Bedding
Jointing
(mm)
0 to 1
1 to 10
10 to
100
100 to
>1,000
Very thinly
laminated
Thinly to 
thickly
laminated
Very thin 
to thinly
Dedded
Medium
Dedded
Thick
Dedded
Very close to close
jointed Medium 1,000 
jointed Wide jointed
Weathering Grades
Fresh
No visible sign of rock 
weathering. 
Rock rings under hammer line.
if crystal-C-27
Faintly weathered                     Discoloration of major discontinui ties. Rock rings under hammer if crystalline.
Slightly weathered                   Discoloration of rock and discon tinuities. Rock has dull or clunk sound under hammer and is somewhat weaker than fresh rock.
Moderately weathered
Highly weathered
• Less than 50% of rock decomposed or disintegrated to soil. Fresh or discolored rock present either as continuous framework or as core
stones.
Greater than 50% of rock decomposed or disintegrated to soil. Fresh or discolored rock present either as continuous framework or as core stones.
Completely 
weathered
One hundred percent of rock decomposed or disintegrated to soil;
original rock structure remains.
Residual soil
All rock converted to soil;
original structure destroyed.
Rock Strength Very strong
Cannot be scratched with knife. More than one blow of hammer required to break sample.Grain      size      of      rocks (cont)
Discontinuity
characteristics
C-26 Description
Medium grained Fine grained Very fine
grained Spacing Bedding (mm)
0 to 1
Grain Size
(mm)
0.060 to 2.000 0.002 to 0.060 
<0.002 Jointing
Very thinly laminated
1 to 10
10 to 100
100 to >1,000
Thinly to thickly laminated
Very thin to tninly oedded
Medium Dedded
Thick Dedded
Very close to close
jointed Medium 1,000 
jointed Wide jointed
Weathering Grades Fresh
No visible sign of rock weathering. Rock rings under nammer if crystal line.C-27
Faintly weathered
Slightly weathered
Moderately weathered
Highly weathered
Discoloration of major discontinui
ties. Rock rings under hammer if crystalline.
Discoloration of rock and discon tinuities. Rock has dull or clunk 
sound under hammer and is somewhat weaker than fresh rock.
- Less than 50% of rock decomposed or disintegrated to soil. Fresh or discolored rock present either as continuous framework or as core
stones.
Greater than 50% of rock decomposed or disintegrated to soil. Fresh or discolored rock present either as continuous framework or as core stones.
Completely 
weathered
One hundred percent of rock decomposed or disintegrated to soil;
original rock structure remains.
Residual soil
All rock converted to soil;
original structure destroyed.
Rock Strength Very strong
Cannot be scratched with knife. More than one blow of hammer required to break sample.C-28
Strong
Moderately strong
Moderately weak
Can be scratched with knife with difficulty. Can De broken with one hammer blow.
Can be scratched easily with knife;
5-mm indentations with blow of sharp pick.
Can De gouged with knife; 2-mm
indentations by firm pressure of
Weak
Very weaK rock or
hard soil
sharp pick.
Crumbles under blows of sharp pick. Can be scratched with fingernail;
may be broken in nand with 
difficulty.Test Pit Report
JOB p6888
PIT TAD-1 SHEET 1 OF 2
CLIENT Ethiopian Electric Light and Power Authority (EELPA) PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu CONTRACTOR       Local labor METHOD  OF
Hand dug with shovel and Sunny and clear
Geology pick
SITE Tiliku Aleltu - Left Bank Drawing DEPARTURE
STARTED 12:00                26/10/83
EXCAVATION
WEATHER
ELEVATIONS: DATUM MSL GROUND SURFACE 2,587.46 ROCK SURFACE Not encountered
TRENCH LENGTH          2.0
FINISHED 10:00 TEMPERATURE
BOTTOM OF PIT
1/11/83 2,583-26
WATER LEVEL Not encountered
WIDTH           2.0 
DEPTH
4.2
OEPTH SOIL TYPE                   DESCRIPTION
0.00  Silty clay Reddish brown silty clay with
with sand and cobbles
some sand and subangular to sub- rounded cobbles up to 15 cm in size, hard becoming very stiff with depth, greasy to gritty texture, heterogenous, moist, highly plastic, slight organic
odor and organic roots to 0.3m
SAMPLE
•TYPE NO. SIZE DEPTH qu_
(mm)       (m) GS                 1           Bulk         0.20
to 0.55
GQ                 2            Bulk         0.30 to 1.00
GQ                 3           Bulk         1.00 to 2.00
GS                 4           Bulk
0.55 to
0.90
GS                 5            Bulk        0.90 
to
2.70
0.50               4.5+
to
to
1.00
3.75
1.50
3.6
to
to
2.00
3.8
2.50
3.8
to
to
3.00
3.6
sampling methoo
•g _ thin wall tuoe
G — snoval
rt — carved Oioc*
INSPECTOR _Sevoum
SHIPPING CONTAINER
0 — tuoe
P — tin
Q — glass jar
S — piartic jag
T - metal can
U — woocin oox
GQ                6           Bulk         2.00
to
3.00
QU   unconfined comore^sive strength
in Kg/cm* measured with oocKet oenatromexer
A — doth bag                Z — discarded
Lemina
L0GGED P- Valliappan, Said Mohammed
APPROVED DATE
Form 314 A 1tt Test Pit Report
JOB P6888 PIT TAD-1 SHEET 1 OF 2
CLIENT Ethiopian Electric Light and Power Authority (EELPA) PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu Geology Drawing CONTRACTOR Local labor
METHOD OF
EXCAVATION Hand dug with shovel and pick WEATHER             Sunny and clear ELEVATIONS: DATUM MSL
GROUND SURFACE 2,587.46 ROCK SURFACE Not encountered
SITE Tiliku Aleltu - Left Bank DEPARTURE
STARTED 12:00  26/10/83
FINISHED 10:00 
TEMPERATURE
1/11/83
BOTTOM OF PIT              2,583.26 WATER LEVEL Not encountered
TRENCH LENGTH 2.0
WIDTH 2.0
DEPTH 4-2 SAMPLE
DEPTH        SOIL TYPE           DESCRIPTION
0.00                   Silty clay           Reddish brown silty clay with with sand            some sand and subangular to sub-
and cobbles        rounded cobbles up to 15 cm in size, hard becoming very stiff with depth, greasy to gritty texture, heterogenous, moist. highly plastic, slight organic odor and organic roots to
0.3 m
•TYPE          NO.         SIZE       DEPTH        Tt
(mm)
(m)
GS                 1            Bulk       0.20 to 0.55
GQ                 2             Bulk       0.30 to 1.00
GQ                 3             Bulk       1.00 to 2.00
GS                 4             Bulk
0.55 
to
0.90
GS                 5             Bulk       0.90 
to
2.70
0.50                   4.5*
to
to
1.00 3.75
1.50                3.6
to
to
2.00
3.8
2.50
3.8
to
to
3.00
3.6
GQ                6             Bulk       2.00 to 3.00
sampling method
SHIPPING CONTAINER
_ thin wall tuoa G - snoval
□ - xuoa
P — xin
s-
T-
PKSXIC
nrwxai can
H — arvea oiocx
qu unconf mao comoressve srrongrh
• n Kg, cm^ maasuraa wixh oocxax panaxromexar
Q - glass gar
A — aoxn oag
U-
z -
wooaan box
discaroaa
imspfcTOR
Seyoum
Lemma
LOGGED P. Valliappan, Said Mohammed
Form 31 4 A liTest Pit Report
job p6838
PIT TAD-1
SHEET 2 OF 2
SAMPLE
DEPTH          SOIL TYPE            DESCRIPTION
3.00                     Silty clay            Yellowish brown silty clay with some fine to medium sand size particles, hard, greasy to
gritty texture, homogenous, highly plastic (residual soil derived from weathering of basalt)
•TYPE         NO.         SIZE      DEPTH       qu_
imml
(m)
3.50                 4.5* GS                7            Bulk       2.70
to 4.20
GQ               8            Bulk       3.00 to 4.00
4.20 
Bottom of test pit
Note:           1 - The walls of the pit were stable and almost ver tide.
2 - No sign of any collapse of the walls observed during logging on November 30, 1983.
Form 314 A 2‘■
Test Pit Report
CLIENT       Ethiopian       Electric       Light       and       Power       Authority PROJECT Aleltu Hydro Project
LOCATION     LATITUDE     See     Tiliku     Aleltu     Geology     Drawing CONTRACTOR Local labor
METHOD OF
JOB P6888 
PIT TAD-2
SHEET 1 OF 2
(EELPA)
SITE     Tiliku     Aleltu     -     Left     Bank DEPARTURE
STARTED        15:40        28/10/83
EXCAVATION WEATHER
Hand     dug     with     shovel     and     pick,     and     hand auger
Sunny and clear
2/11/83
ELEVATIONS: DATUM
GROUND SURFACE
MSL
2,578.13
FINISHED 09:30 TEMPERATURE BOTTOM OF PIT 2,571.76 WATER LEVEL See Note 3
ROCK SURFACE                2,574.83 TRENCH LENGTH 2.00
WIDTH 2.00
DEPTH 4.0 (test pit)
4.00 to 6.37 (auger hole) SAMPLE
DEPTH       SOIL TYPE         DESCRIPTION
•TYPE        NO.        SIZE       DEPTH       qu
0.00                    Silty clay     Dark brown grading to dark gray silty clay with trace of sub- rounded gravel and cobbles of basaltic composition up to
10 cm in size, hard becoming very stiff with depth, greasy to gritty texture, heterogenous, moist, medium to highly plastic, slight organic odor and organic roots to 0.3 m
3.30             Weathered             Light to yellowish brown basalt
basalt
moderately weak to weak, com- pletely weathered with frag ments of moderately strong basalt up to 15 cm m size
(mm/      (m)
GQ               1           Bulk      0.30
to
1.00
GS               2            Bulk      0.30
to
1.60
0.50             4.5*
1.00             3.3
1.50             3.3
2.00              3.3
2.50             2.7
3.00             2.6 GS                3           Bulk       1.60
to 3.00
GQ               4           Bulk       2.00 to 3.00
GS               5           Bulk       3.30 to
4.00
SAMPLING METHOO
SHIPPING CONTAINER
•9 — thin wall tub®
G - sftove*
H — carvea diock
0 - tuoa
P — tin
□ - giau jar
R - ciotn bag
s -   pianic
T -    merai an
U - woocen pox
z -   dijcaraea
qu uncontmea compressive strtngtn
n «cg/cm“ measured with pocket penetrometer
imsppctor Seyoum            Lemma
AP°ROVED
-
uOGGED p, Valliappan, Said Mohammed
° ATc Pecember" •___________________________________
Corm 314 m 11Test Pit Report
J0B P6888
PIT TAD-1
SHEET 2 OF 2
SAMPLE
DEPTH          SOIL TYPE            DESCRIPTION
3.00                     Silty clay            Yellowish brown silty clay with some fine to medium sand size particles, hard, greasy to
gritty texture, homogenous, highly plastic (residual soil derived from weathering of basalt)
•TYPE         NO.         SIZE (mm)
DEPTH (m)
qu_
3.50                 4.5+ GS                7            Bulk       2.70
to 4.20
GQ               8            Bulk       3.00 to 4.00
4.20
Bottom of test pit
Note:                  1 - The walls          of the pit were stable and almost verticle.
2 - No sign of any collapse of the walls observed during logging on November 30, 1983.
Form 314 A 12Test Pit Report
CLIENT        Ethiopian        Electric        Light        and        Power        Authority PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu Geology Drawing
CONTRACTOR
METHOO OF EXCAVATION
Local labor
Hand  dug  with  shovel and  pick, and  hand 
JOB P6888
PIT TAD-2
SHEET 1 OF 2
(EELPA)
SITE Tiliku Aleltu - Left Bank DEPARTURE
started         15:40        28/10/83
FINISHED
09:30           2/11/83
weather
auqer
Sunny
and clear
ELEVATIONS; DATUM       MSL GROUND SURFACE           2,578.13 ROCK SURFACE                 2,574.83
TRENCH LENGTH
2.00
WIOTH 2.00
TEMPERATURE BOTTOM OF PIT 2,571.76 WATER LEVEL See Note 3
DEPTH 4.0 (test pit)
4.00 to 6.37 (auqer hole) SAMPLE
DEPTH       SOIL TYPE          DESCRIPTION
0.00                     Silty clay     Dark brown grading to dark gray silty clay with trace of sub- rounded gravel and cobbles of basaltic composition up to
10 cm in size, hard becoming very stiff with depth, greasy to gritty texture, heterogenous, moist, medium to highly plastic, slight organic odor and organic roots to 0.3 m
•TYPE        NO.         SIZE (mm;
DEPTH (m)
qu.
3.30           Weathered             Light to yellowish brown basalt
basalt
moderately weak to weak, com- pletely weathered with frag- ments of moderately strong basalt up to 15 cm in size
GQ               1          Bulk       0.30
to
1.00
GS                2           Bulk       0.30
to
1.60
0.50               4.5* 1.00               3.3
1.50               3.3
2.00               3.3
2.50              2.7
3.00               2.6 GS                3          Bulk        1.60
to 3.00
GO               4          Bulk        2.00 to 3.00
GS                5           Bulk        2.30 to
4.00
SAMPLING    method
SHIPPING CONTAINER
•g — trim wall tune
G - snovei
rt - arvea     OIOCM
INSPECTOR Seyoum Lemma
0 - tuo«
P — rm
Q - glass jar
S — plastic oaq
T — metai can
U - woooen sox
qu unconti
compressive strength
m Kg . cm2     measu re a with pocKet penetrometer
R — doth oag                Z - discaraea
a 4 \ APPROV=D     ^1A vl
r
LOGGED      P. ValliaDpan. Said Mohammed 
DATE Decemhp^ IQTest Pit Report
DEPTH        SOIL TYPE DESCRIPTION
JOB P6888
PIT TAD-2 SHEET 2 OF 2
SAMPLE________________________ -TYPE NO. SIZE DEPTH
Imm) (m)
qu
6.37 
Bottom of test pit
No te: 1  - Hole advanced with auger below 4.0 m.
2   - Observed tension cracks and caving of walls to 3.0 m during logging on November 30, 1983.
3   - Water levels in test pit and auger hole.
Date
Depth
2/11/83
3/11/83
4/11/83 
14/11/83
30/11/83
(m)
6.00 5.33
5.17
5.17
5.50
i
^orm 314 A 2'a
Test Pit Report
CLIENT Ethiopian Electric Light and Power Authority (EELPA) PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu Geology Drawing CONTRACTOR   Local labor
METHOD OF
EXCAVATION
Hand dug with shovel and pick
WEATHER Sunny
ELEVATIONS: DATUM
and clear
MSL
GROUND SURFACE 2,563.88
ROCK SURFACE 2,561.48
J0B psese PIT TAD-3 SHEET 1 OF 1
SITE Tiliku Aleltu - Left Bank DEPARTURE
STARTED 07:30           27/10/83
FINISHED 14:00           28/10/83 TEMPERATURE
BOTTOM OF PIT 2,563.03 WATER LEVEL Not encountered
T
RENCH LENGTH 2.00                                 WIDTH 1.50                                  DEPTH
q.85
SAMPLE
DEPTH      SOIL TYPE          DESCRIPTION
•TYPE
NO.
SIZE
DEPTH
(mml
(mJ
0.00                      Silty clay
Dark brown silty clay with trace     GZ                1           Bulk      0.00
of subrounded gravel and cobbles
of basaltic composition up to
to
0.4C
15 cm in size, greasy to gritty 
texture, heterogenous, moist,
highly plastic, slight organic
odor and organic roots to 
0.3 m
0.40 Weathered 
Dark gray fine grained
basalt
aphanitic basalt, moderately
strong to very strong, moder
ately weathered to faintly 
weathered with depth, columnar
jointed with block sizes rang
ing from 15 to 25 cm
q.85 
Bottom of test pit
Note: Unanle to dig with hand tools below 0.85 m.
sampling methoo
SH
IPPING CONTAINER
•g - mm wall tude
□ - tuoe
s -
pianic oag
qu uncon*into compressive rtrengtn
q _ snovei
P - tin
T -   metal can
m                    measured with pocket oenetrometer
M — carved Diock
Q - glass jar
U-
wooaen oox
R - clotn oag
z -
discarded
.mcpppTOR Seyoum
Lemma
APPROVED
W OGGED P. Valliappan, Said Mohammed
DATE December 1983
Form 314 A Hi»OT
Test Pit Report
JOB P6888 PIT TAD-4 SHEET 1 OF 1
CLIENT Ethiopian Electric Light and Power Authority (EELPA) PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu Geology Drawing
CONTRACTOR
METHOD OF EXCAVATION
WEATHER ELEVATIONS:
Local labor
Hand dug with shovel and pick Sunny      and clear
DATUM
MSL
GROUND SURFACE 2,567.38 ROCK SURFACE 2,567.08
TRENCH LENGTH 1-50
WIDTH 1.50
DEPTH SOIL TYPE                  DESCRIPTION
SITETiliku Aleltu - Right Bank DEPARTURE
STARTED 11:00                1/11/83
FINISHED 08:45               2/11/83 TEMPERATURE
BOTTOM OF PIT 2,566.23
WATER LEVEL Not encountered
DEPTH 1.15
SAMPLE
TYPE        NO.        SIZE       DEPTH       qu imml      ImJ
0.00              Silty clay                Dark       gray       silty       clay       with       trace of subrounded gravel and
cobbles of basaltic composition up to 15 cm in size, greasy to gritty texture, heterogenous, moist, highly plastic, slight organic odor and organic roots to 0.3 m
Weathered             Light gray fine grained basalt,
GZ               1            Bulk     0.00 to 0.30
basalt
1.15
vesicular with vesicles par tially filled with white zeo- litic minerals, moderately strong becoming strong with depth, slightly weathered to faintly weathered with deptn, columnar jointed with Dlock sizes ranging from 15 to 30 cm, probably top of flow covering river bed
Bottom of test pit
Note:          1  - Unable to dig with hand tools below 1.15 m. 2   - A topographical low depression exists about
20 m downstream from pit.
sampling methoc
-   thin wall tube
SHIPPING CONTAINER
-   .novel
- carved oiock
O - tube
P — tin
S — olastic oag T — metai san
qu uncontineo compressive
■n kg/cm* measured  .tn
w        pocket
strength
Q — glass jar
R — ciorh oag
U — wooden box Z — discarded
.NSPSCTOR jevc/un Lemma
APPROVED
LOGGED p. Valliappan, Said Mohammed
DATE December 198 3
Form 314 A 11co o r
Test Pit Report
CLIENT Ethiopian Electric Light and Power Authority PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu Geolooy Drawing CONTRACTOR      Local labor
METHOD OF
EXCAVATION
Hand dug with shovel and pick
WEATHER              Sunny and clear ELEVATIONS: DATUM MSL
GROUND SURFACE 2,585.40
ROCK SURFACE Not TRENCH LENGTH 2.0
encountered
WIDTH 2.0
DEPTH SOIL TYPE            DESCRIPTION
0.00            Silty clay              Dark brown silty clay with trace of sand and subangular cobbles up to 15 an in size, hard becom- ing stiff around 3.0 m and
JOB P6888
PIT TAD-5
SHEET 1 OF 2
(EELPA)
SITE Tiliku Aleltu - Right Bank DEPARTURE
STARTED        09:30 2/11/83
FINISHED        17:00 7/11/83 TEMPERATURE
BOTTOM OF PIT 2,580.70
WATER LEVEL Not encountered
DEPTH 4.7
SAMPLE
•TYPE        NO.        SIZE      OEPTH        qu
•
increasing to very stiff below, greasy to gritty texture, hete- rogenous, moist, highly plastic, slight organic odor and organic roots to 0.3 m, concentration of basaltic cobbles in places
GQ               1
GQ               2
GQ               3
GQ               4
(mm)      (m2 0.30
to 1.00 1.00 to 2.00 2.00 to 3.00 3.00 to 4.00
0.50              4.5+ 1.00            4.1
1.50            3.6
2.00            3.6
2.50            1.9
3.00            1.8 3.50            3.2 4.00            3.9
4.70
Bottom of test pit
GS                5             Bulk      0.50 to 4.50
SAMPLING METHOD
SHIPPING CONTAINER
-   tn«n wall tuoa
w - tUD*
S - oianic Dag
-   snovel
P - rm
qu unconfmaa compress>va strength
T - meiai can
-   carveo piock
Q - glass |ir
•n Kg/cm^ measured with pocKet penetrometer
U - wooden pox
R - doth oag
Z - d'jcarata
INSPECTOR Seyoum Lemma LOGGED P. Valliappan, Said Mohammed
DATE    December 1983
corm 314 A 111Test Pit Report
JOB p680e
PIT TAD-4 SHEET
CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu Geology Drawing DEPARTURE
SITETiliku Aleltu - Right Bank
CONTRACTOR
METHOD OF
EXCAVATION
Local labor
Hand dug with shovel and pick
STARTED
FINISHED
11:00
08:45
1/11/83
2/11/83
WEATHER               Sunny     and clear
ELEVATIONS:   DATUM
MSL
GROUND SURFACE 2,567.38 ROCK SURFACE 2,567.08
TRENCH  LENGTH 1.50
WIDTH 1.50
OEPTH        SOIL TYPE           DESCRIPTION
TEMPERATURE
BOTTOM OF PIT 2,566.23 WATER LEVEL Not encountered
DEPTH 1.15
SAMPLE
•TYPE        NO         SIZE      DEPTH
(mm J
0.00
Silty clay
Dark gray silty clay with trace
GZ
1
Bulk
of subrounded gravel and
cobbles of basaltic composition 
up to 15 cm in size, greasy to 
gritty texture, heterogenous,
0.30
moist, highly plastic, slight organic odor and organic roots to 0.3 m
Weathered            Light gray fine grained basalt,
basalt
1.15
Note: 1
vesicular with vesicles par tially filled with white zeo- litic minerals, moderately strong becoming strong with depth, slightly weathered to faintly weathered with depth, columnar jointed with block sizes ranging from 15 to 30 cm, probably top of flow covering river bed
3ottom of test pit
-   Unable to dig with hand tools below 1.15 m.
2   -   A topographical low depression exists about 20   m  downstream from pit.
SAMPLING METHOD
*B - thin «ail tube
G — snovai
m — carvao oiock
SHIPPING CONTAINER
O — ruD«
P — tin
a — glass |ir
R — cloth nag
S
T
U
z
piastre Dag
marai can
woooan dox
discaroao
□ nconr.naa comprewve srrengtn
n 'naawrto w.th pockat panatromatar
INSPECTOR
Sevoum Lemma
LOGGED p. Valliappan, Said Mohammed
APPROVED DATE
Form 314 A 11 lTest Pit Report
JOB P6888 PIT TAD-5 SHEET 1 OF 2
CLIENT
Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION   LATITUDE See Tiliku Aleltu Geolocry Drawing DEPARTURE CONTRACTOR      Local labor
METHOO OF
EXCAVATION
Hand dug with shovel and pick
STARTED
FINISHED
SITE Tiliku Aleltu - Right Bank 09:30         2/11/83
17:00        7/11/83
WEATHER             Sunny and clear ELEVATIONS: DATUM MSL
GROUND SURFACE 2,585.40 ROCK SURFACE Not encountered
TRENCH LENGTH      2.0
TEMPERATURE
BOTTOM OF PIT 2,580.70 WATER LEVEL Not encountered
WIDTH
2.0
DEPTH
4.7
DEPTH      SOIL TYPE
SAMPLE
•TYPE        NO.        SIZE      OEPTH       51 imml
(m?
0.00
Silty       clay
DESCRIPTION
Dark brown silty clay with trace of sand and subangular cobbles up to 15 cm in size, hard becom- ing stiff around 3.0 m and increasing to very stiff below. greasy to gritty texture, hete- rogenous, moist, highly plastic, slight organic odor and organic roots to 0.3 m, concentration
of basaltic cobbles in places
GQ               1
GQ               2
GQ               3
GQ               4
0.30
to
1.00
1.00
to
2.00
2.00
to
3.00
3.00
to
4.00
0.50             4.5* 1.00            4 1
1.50            3.6
2.00            3.6
2.50            1.9
3.00            1.8 3.50            3.2 4.00            3.9
4.70
Bottom of test pit
GS                5             Bulk      0.50 to 4.50
sampling
method
SHIPPING CONTAINER
*9 - thin wall tuoe
G - jfiovti
ri — carvwa oiock
INSPECTOR Spyoiim Lemma
0 - tuoe
P — tin
Q - glass jar
R - aotn bag
S - Plastic oag
T     -    metal on
wooden oox
dtscaraea
U-
qu unconfined compressive strength
in <g/cm^ measurea with pocxet penetrometer
z -
APPROVED
LOGGED
P. Valliappan, Said Mohammed
Form 314 A 1SAMPLE
DEPTH SOIL TYPE DESCRIPTION
Note:          1 - The walls of the test pit were stable
and almost verticle.
2              - No sign of any collapse of the walls ODserved during logging on November 30, 1983.
TYPE        NO.         SIZE (mm/
DEPTH (m)
Form 314 A i2Test Pit Report
JOB P6888 PIT TINAD-1 SHEET 1 OF 1
CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tinishu Aleltu Geology Drawing DEPARTURE CONTRACTOR Local labor
METHOD OF
EXCAVATION   Hand dug with shovel and pick WEATHER          Sunny and clear ELEVATIONS: DATUM        MSL
GROUND SURFACE ROCK SURFACE
TRENCH LENGTH 2.0
2,592.77
2,591.97
SITE Tinishu Aleltu - Right Bank STARTED 09:00              15/11/83
FINISHED 15:30             16/11/83 TEMPERATURE
BOTTOM OF PIT 2,591.57 WATER LEVEL Not encountered
WIDTH 2.0
DEPTH 1>2
DEPTH      SOIL TYPE         DESCRIPTION
0.00                      Silty clay     Dark reddish brown silty clay with trace of coarse sand and subangular basalt fragments up to 10 cm in size, hard, floury to gritty texture, hete- rogenous, moist, highly plastic, slight organic odor and organic
roots to 0.3 m, sand and
SAMPLE
*TYPE        NO.        SIZE       DEPTH       qu
Imml      (mJ
GQ               1           Bulk      0.20
to
0.80
GS               2            Bulk      0.20
to
0.80
0.50                4.5 0.80                4.1
cobble
content
increases
toward 
bottom
(soil
mainly 
transported 
talus)
0.80 Weathered Dark gray basalt, medium grained 
basalt plagioclase crystals in a fine
grained ground mass, strong to very strong, columnar jointed and blocky at surface with average size of blocks about 15 cm, moderate to highly 
weathered
1.20
Note:
Bottom of test pit
Unable to dig with hand tools below 1.2 m.
sampling method
•g - thin wail tune
G - snovei
h - arvea oiock
SHIPPING CONTAINER
0         - tune                   S  -     oustic oaq
P        - tin                      T  -      metal an
Q - gnu tar U - wooden box
R         - clothoag           Z  -     □ uaraea
inspector           Sevoum     ■ueimna LOGGED p. Valliappan, Said Mohammed
qu unconfineo compressive strength
■n Kg/cm^ measured with pocket penetrometer
APPROVED
OATE December TL983
Form 314 A 11Test Pit Report
P6888 JOB
PIT TINAD-2
SHEET 1 OF 2
CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tinishu Aleltu Geology Drawing DEPARTURE
CONTRACTOR    Local labor METHOD OF
SITE Timshu Aleltu - Right
Bank
EXCAVATION
WEATHER
Hand dug with shovel and and clear
Sunny
pick
ELEVATIONS.  DATUM    MSL GROUND SURFACE        2,591.82 ROCK SURFACE             2,590.37
STARTED 09:00
FINISHED 08:30
TEMPERATURE BOTTOM OF PIT WATER LEVEL
15/11/83 17/11/83
2,589.82
1.50 
(see Note 4)
TRENCH  LENGTH
2.0
WIDTH
2.0
DEPTH
2.0
SAMPLE
DEPTH
SOIL TYPE
DESCRIPTION
•TYPE
NO.
SIZE
Immi
OEPTH
Im)
qu
0.00
Silty clay
Dark gray silty clay with trace
GQ
1
Bulk
0.20
of coarse sand and subrounded
to
gravel up to 3 cm in size, very
1.00
stiff to hard, floury to gritty
GS
1
Bulk
0.20
texture, heterogenous, moist, highlv plastic, slight organic odor and organic roots to 0.3 m
(soil mainly transported talus)
1.00             Cobbly                   Transported talus with subrounded clay with                cobble size basalt fragments in sand and                 a matrix of dark gray silty clay grave 1                   with some sand and gravel size
particles, hard, floury to gran ular texture, heterogenous, moist, necoming wet with depth, medium plastic
to 1.00 0.50 1.00
3.75
2.50
1.45
Weathered basalt
METHOD
Brownish gray, fine grained, moderately weak to strong, highly weathered, stained along fracture surfaces, blocky along surface with block sizes ranging from 3 to 20 cm with an 
size around 6 cm
Bottom       of       test       pit
SHIPPING CONTAINER
average
2.00
sampling
*9 - thin wall tuoa
G - snovai
H - arj»d oiock
INSPECTOR Seyoum
0 — tuM
P - tin
Q - giass i«r
R - cloth oaq
S
T
U
z
□u unconfin«a compr«uiVt nrengxn
kJ, cm* m..,urla w„„ Docl<„
Lemma
APPROVED ^J,l DATE December "1983
'z
LOGGED
P.    Valliappan, Said Mohammed
Form 314 A■
Test Pit Report
JOB P6888 PIT TINAD-2 SHEET 2 OF 2
depth so
il type de
scription
SAMPLE______________________ -TYPE NO SIZE DEPTH
qu
Imm) (m)
Note:
1 - Unable t
o excavate below 2
.0 m because
of
seepage      and 
accumulation 
of
ground
water.
2              - Weathered basalt appears to be highly permeable and the water accumulated in the pit is clear.
3  - Pit appears to be stable and no sign of caving of wall observable.
4  - Water levels in test pit. Date                Depth
(m)
16/11/83
17/11/83
23/11/83
1.50
1.57
1.55CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tinishu Aleltu Geolocy Drawing DEPARTURE CONTRACTOR      Local labor
METHOO  OF
SITE Tinishu Aleltu - Left Bank STARTED         09:00          15/11/83
EXCAVATION WEATHER
Hand      dug      with      shovel      and      pick Sunny and clear
16/11/83
elevations. OATUM           MSL
FINISHED 15:15 TEMPERATURE BOTTOM OF PIT 2,589.97
GROUND SURFACE ROCK SURFACE
TRENCH LENGTH 2.0
2,591.17
2,590.07
WIDTH 2.0
WATER       LEVEL       1.15       (15/11/83       and 23/11/83)
DEPTH 1.2
SAMPLE
DEPTH
SOIL TYPE
DESCRIPTION
•TYPE
NO.
SIZE
(mm)
DEPTH
0.00
Silty clay
Yellowish gray becomina reddish
GQ
1
Bulk
0.20
with sand and cobbles
brown with depth, silty clay with some sand and subangular cobbles of basalt, hard, floury to gritty texture, neterogenous, moist becoming wet with deptn, medium plastic, slight organic odor and organic roots to
0.2 m
to 1.00
GS                1            Bulk       0.20 to 1.00
0.50
0.70              Silty clay                 Dark gray silty clay with trace
of medium to coarse sand, stiff,
floury to gritty texture, homo-
genous,       wet,       medium       to       highly plastic, slight organic odor
1.00
1.10              Weathered basalt
1.20
Dark gray basalt, strong to very strong, columnar jointed and blocky at surface with an average block size of 15 cm, faintly weathered
Bottom of test pit
Note:                       Unable to dig   with hand tools below 1.2 m.
sampling method
SHIPPING CONTAINER
’9 — thin wall tube
G - snovel
□ - ube
r
P — tin
S-
T-
piarric bag
metal can
qu uncontmea comprewve strength
h — carved mock
□ - glass iar R - cloth bag
U-
z -
wooden oox discarded
m
m..wr«a w«h pocx.t p.n.trom.«r
.NSPECTOR Sevoum Lemma
z--
LOGGED p. Valliappan, Said Mohammed
December ^983
Form 3’4 A 1Test Pit Report
JOB P6888 PIT RJD-1 SHEET 1 OF 1
CLIENT Ethiopian Electric Light PROJECT Aleltu Hydro Project LOCATION LATITUOE See Robi Jida
CONTRACTOR
METHOD OF
EXCAVATION
Local labor
Hand dug with shovel
and Power Authority (EELPA) Geology Drawing
and pick
SITE Robi Jida - DEPARTURE STARTED 08:30
FINISHED 12:30
Left Bank 4/11/83
5/11/83
WEATHER           Sunny
and clear
TEMPERATURE
ELEVATIONS: DATUM
MSL
BOTTOM OF PIT
2,573.94
GROUND SURFACE
2,575.74
WATER LEVEL
ROCK SURFACE
2,574.64
1.2 (5/11/83) Dry (29/11/83)
TRENCH LENGTH
2.0
WIDTH
2.0
OEPTH 0.00
SOIL TYPE Silty clay
DESCRIPTION
Dark brown grading to dark gray, silty clay with trace of sub-
rounded gravel and cobbles of basaltic composition up to 30 cm
in size, medium stiff, greasy
to gritty texture, heterogenous, moist, highly plastic, slignt
organic odor and organic roots
to 0.3 m
Light gray, fine grained 
DEPTH 1.8
SAMPLE
•TYPE         NO.         SIZE       DEPTH        qu
(mm)
(mJ
GO                1            Bulk       0.20 to 1.00 0.50 1.00
GS                2            Bulk       0.20 to
1.00
0.9
0.9
1.10
Weathered basalt
apnanitic, moderately
weathered,
completely
moderately weak to strong, moderately at places highly to weathered, columnar
1.80
Note:
jointed  with  block  sizes ranging from 10  to  20  cm m size, highly permeable
Bottom of test pit
1  - Groundwater started seeping from 1.2 m.
2   - Water had to be bailed out during excavation.
3  - Pit dry during logging on November 29, 1983.
4   - A spring about 30 m from the test pit possibly marking the contact between flow units of basalt.
sampling method
•3 — trim wall tuoe
G - snovei
k - carved diock
INSPECTOR Seyoum
.OGGED          P.
SHIPPING CONTAINER
0 - tuoe
S
-   aianic bag
P — tin
T
-   'natal an
□ - gnu jar
U
-   wooden oox
qu unconrjneo compressive strength
in •cg^cm* - measured with pocket penetrometer
1
A - dotn oeg
z -      disarrjea
Lemma
Valliappan, Said Mohammed
APPROVED DATE oeTest Pit Report
JOB P6888 PIT TINAD-3 SHEET 1 OF 1
CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tinishu Aleltu Geology Drawing DEPARTURE
contractor
METHOO OF EXCAVATION
WEATHER Sunny
Local labor
Hand dug with shovel and pick and clear
SITE Timshu Aleltu - Left Bank STARTED          09:00          15/11/83
16/11/83
ELEVATIONS: DATUM GROUND SURFACE ROCK SURFACE
TRENCH LENGTH 2.0
MSL 2,591.17 2,590.07
FINISHED 15:15 TEMPERATURE BOTTOM OF PIT 2,589.97
WIDTH 2.0
DEPTH        SOIL TYPE             DESCRIPTION
0.00 Silty clay Yellowish gray becomina reddish
WATER       LEVEL       1.15       (15/11/83       and 23/11/83)
DEPTH i,2
SAMPLE
•TYPE         NO.         SIZE       DEPTH
(mm)       (m) GQ                1            Bulk       0.20
with sand and cobbles
brown with depth, silty clay with some sand and subangular cobbles of basalt, hard, floury to gritty texture, heterogenous. moist becoming wet with depth, medium plastic, slight organic odor and organic roots to
0.2 m
to 1.00
GS                 1            Bulk       0.20 to 1.00
0.50
4.30
0.70                     Silty clay            Dark gray silty clay with trace of medium to coarse sand, stiff, floury to gritty texture, homo genous, wet, medium to highly plastic, slight organic odor
1.10 Weathered Dark gray basalt, strong to very
1.00
1.55
basalt
1.20
strong, columnar jointed and blocky at surface with an average block size of 15 cm, faintly weathered
Bottom of test pit
Note:          Unable to dig with hand tools below 1.2 m.
sampling method
SHIPPING CONTAINER
*3 — thm wall tube
O
- tuo«
S-
plastic dag
qu unconfined compressive strength
G — tnovei
P
- tin
T-
metal   can
M — carv«o Slock
•n <g,cm2 measured                p.
Wl<h QOCk-t      nttrom<ttr
□
— glass jar
U—
AOOdin dox
R
- aotn oag
Z—
discarded
INSPECTOR Sevoum Lemma------------------------------------------------ LOGGED           P. ValLiapoar., Said Mohammed
Form 314 A 1)n
Test Pit Report
JOB P6888 PIT RJD-1 SHEET 1 OF 1
CLIENT Ethiopian Electric Light PROJECT Aleltu Hydro Project
and Power Authority (EELPA)
SITE Robi Jida - DEPARTURE
Left Bank
LOCATION . LATITUOE See Robi Jida                Geology Drawinq CONTRACTOR   Local labor
METHOD OF
EXCAVATION    Hand dug with shovel WEATHER           Sunny and clear ELEVATIONS: DATUM MSL
GROUND SURFACE 2,575.74 ROCK SURFACE 2,574.64
TRENCH LENGTH 2.0
and pick
STARTED 08:30               4/11/83
FINISHED 12:30              5/11/83 TEMPERATURE
BOTTOM OF PIT 2,        573.94 WATER LEVEL       1.2 (5/11/83)
Dry (29/11/83)
WIDTH 2.0
DEPTH      SOIL TYPE          DESCRIPTION
0.00                      Silty clay     Dark brown grading to dark gray. silty clay with trace of sub- rounded gravel and cobbles of basaltic composition up to 30 cm
in size, medium stiff, greasy
to gritty texture, heterogenous.
DEPTH 1.8
SAMPLE
•TYPE        NO.         SIZE       OEPTH       qu
(mm)      Im} GO                1            Bulk      0.20
to 1.00
0.50                0.9
1.00                0.9
GS                2            Bulk       0.20
moist, highly plastic, slight
to
organic odor and organic roots
1.00
to 0.3 m
1.10 Weathered Light gray, fine grained 
basalt
aphanitic, moderately weak to
moderately strong, moderately 
weathered, at places highly to 
completely weathered, columnar
jointed with block sizes ranging 
from 10 to 20 cm in size, highly 
permeable
1.80 
Bottom of test pit
Note:         1 
- Groundwater started seeping from 1.2 m.
2 
- Water had to be bailed out during excavation.
3 
- Pit dry during logging on November 29, 1983.
4 
- A spring about 30 m from the test pit possibly
marking the contact between flow units of
basalt.
SAMPLING METHOO
SH
IPPING
CONTAINER
■g — trim wall tuoe
0 - tuoe
s -
oiasxic Dag
5u unconfined compressive strengtn
3 - snovel
P - tin
T-
metal can
n - sarved oiock
<n Kg.cm^ measured with pocket penetrometer
□-
jar
U-
wooden oox
R - doth Dag
z -  discarded
incpfcTOR Seyoum          Lemma
logged ?. Valliappan, Said Mohammed
APPROVED
Da.E DecemoeY 1983Test Pit Report
JOB P6888 PIT RJD-2 SHEET 1 OF 1
CLIENT          Ethiopian Electric Light
PROJECT LOCATION
Aleltu Hydro Project LATITUDE See Robi Jida
and Power Authority (EELPA) Geology Drawing
and pick
SITE Robi Jida - DEPARTURE
CONTRACTOR        Local labor METHOD   OF
EXCAVATION
Hand dug with shovel
STARTED
FINISHED
09:00
16:00
Left Bank 3/11/83
8/11/83
WEATHER               Sunny
ELEVATIONS.
DATUM
GROUND SURFACE ROCK SURFACE
and clear MSL 2,562.89 2,561.24
TEMPERATURE
BOTTOM OF PIT 2,558.29
WATER LEVEL 4.40 (14/11/83)
3.80               (29/11/83)
See Notes 3
and 4
TRENCH   LENGTH                 2.0
WIDTH
2.0
DEPTH
SAMPLE
4.6
DEPTH 0.00
SOIL TYPE             DESCRIPTION
Silty clay                  Dark gray grading to dark brown below 1.10 m, silty clay with trace of subrounded gravel and coobles of basaltic composition up to 15 cm in size, stiff,
greasy to gritty texture, hete- rogenous, moist, medium to highly plastic, slight organic odor and organic roots to
0.3 m
Weathered                Light gray, fine grained basalt
•TYPE
NO.
SIZE
Imml
DEPTH
(m)
qu
GQ
1
Bulk
0.20
to
1.00
0.50
1.00
1.10
1.25,
GS
2
Bulk
0.20
to
1.15
1.65
GQ
3
Bulk
1.00
basalt
vesicular, moderately weak, highly to completely weathered, vesicles filled with white zeo- litic minerals, possibly top of flow, considerably weathered, highly permeable
Bottom of pit
to
2.00
GS
4
Bulk
1.15
to
1.70
4.60
Note:          1 2
The walls of the pit were stable and 
almost vertical.
No sign of any collapse of the walls observed during logging on November 29, 1983.
3   - Groundwater started seeping from 3.73 m.
4   - Water
sampling methoo
•8 — thm wall tub®
G — shovel
M — carved block
INSPECTOR Sevoum
collected in the pit is verv clear.
SHIPPING CONTAINER
□           - tube               S p          - tin                  T
Q        — glass ar
t
A          - doth bag       Z
Lemma
U•
qu unconhnea compr«uiv« strength
measured with pocxet penetrometer
APPROVED
LOGGED
P. Valliappan
Form 314 All)b
Test Pit Report
J0B 86888 PIT RJD-3 SHEET 1 OF l
CLIENT Ethiopian Electric Light and Power Authority (EELPA) PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Robi Jida Geology Drawing CONTRACTOR       Local labor
METHOD OF
EXCAVATION        Hand dug with shovel and pick WEATHER               Sunny and clear ELEVATIONS: DATUM MSL
GROUND SURFACE 2,555.52
• ROCK SURFACE          2,554.67
SITE Robi Jida - Left Bank DEPARTURE
STARTED 08:50  3/11/83
FINISHED 09:50             4/11/83 TEMPERATURE
BOTTOM OF PIT            2,554.22 WATER LEVEL 0.85 (8/11/83)
TRENCH LENGTH 2.0 
WIDTH 2.0 
DEPTH      SOIL TYPE          DESCRIPTION
0.00                 Silty clay          Dark gray silty clay with trace
of subrounded gravel and cobbles
of basaltic composition up to
30 cm in size, medium stiff,
greasy to gritty texture, hete
rogenous, moist, highly plastic,
slight organic odor and organic
roots to 0.4 m
0.85  Weathered  Light gray, fine grained  basalt
1.20 (29/11/83) OEPTH 1.3
SAMPLE
•TYPE        NO.        SIZE       DEPTH       qu
(mm/      (mJ GQ               1          Bulk      0.20
to
0.80
0.50 0.65
basalt
1.30 
with phenocrists of plagioclase, moderately weak, highly weathered becoming slightly weathered at
the bottom of the pit, highly permeable
Bottom of test pit
Note:         1 - Unable to dig with hand tools oelow 1.30 m. 2   - Water had to be bailed out during excavation. 3  - Water collected in the pit is very clear.
SAMPLING METHOD
SHIPPING CONTAINER
*8 - tnm wall tuoe
G - snovei
0 - tuoe
P - tin
H - carved oiocK
s - plastic sag
T — meta, can
U - wooden oox
Z - aucaraeo
qu unconf mea compressive strength
h Kg/cm* measure a with pocKCt penetrometer
□ - giau jar A - aotn sag
INSPECTOR Seycum Lemma
I
APPROVED
uOGG ED p. Valliappan, Said Mon amine d
□ ATP
Form 314 A > 11Test Pit Report
JOB P6888 PIT RJD-4 SHEET 1 OF 1
CLIENT          Ethiopian          Electric          Light          and          Power          Authority PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Robi Jida Geoloov Drawing CONTRACTOR         Local labor
METHOD   OF
(EELPA)
SITE Robi Jida - Right Bank DEPARTURE
STARTED 08:30 
EXCAVATION          Hand dug with shovel
and pick
10/11/83
10/11/83
WEATHER                Sunny ELEVATIONS: DATUM
GROUND SURFACE ROCK SURFACE
and          clear MSL
2,554.25 2,553.75
FINISHED 17:10 TEMPERATURE BOTTOM OF PIT 2,553.25
PIT LENGTH
2.0
WIDTH 2.0
"bEPTH        SOIL TYPE            DESCRIPTION
0.00               Silty clay                 Dark gray silty clay with trace
of subrounded gravel and cobbles of basaltic composition up to 20 cm in size, medium stiff, greasy to gritty texture, hete rogenous, moist, highly plastic, slight organic odor and organic roots co 0.3 m
0.50              Weathered Light gray# fine grained 
WATER LEVEL Not encountered DEPTH 1.0
SAMPLE_________________________
•TYPE NO. SIZE DEPTH qu
GZ                1
(mm/ (m) Bulk 0.00 
to
0.50
basalt
1.00
aphanitic with phenocrysts of plagioclase and pyroxene, moder ately weak and moderately weathered at the top becoming strong and faintly weathered at the bottom of the pit, columnar jointed with size of blocks ranging from 10 to 25 cm
Bottom of test pit
Note:          Unable to            dig with hand tools below 1.0 m.
SAMPLING METHOD
•fl - rnm wall ruM
G - tn ov«i
h - carved oiock
INSPECTOR Sevoum Lemma
SHIPPING CONTAINER
0 - tube
P — tin
Q - glass jer
A - doth oag
S - oiastic oaq
T - metal can
U - .-■'ooaen dox
Z - d scarped
Qu uncontined compressive strength
• n Kg/cm? measured with pocket penetrometer
LOGGED p. Valliappan, Said Mohammed
APPROVED DATE
\J         IQ 93
Form 3’4 A I11Test Pit Report
CLIENT Ethiopian Electric Light and Power Authority PROJECT Aleltu Hydro Project
LOCATION LATITUOE See Rooi Jida Geology Drawing CONTRACTOR Local labor
METHOD OF
EXCAVATION       Hand dug with shovel and pick WEATHER              Sunny and clear ELEVATIONS: DATUM MSL
GROUND SURFACE 2,562.28 ROCK SURFACE 2,560.93
JOB P6888 PIT RJD-5 SHEET 1 OF 2
(EELPA)
SITE Robi Jida - Right Bank DEPARTURE
STARTED 09:45               7/11/83
FINISHED 17:10 10/11/83 TEMPERATURE
BOTTOM OF PIT 2,559.2 8 WATER LEVEL 2.70 (10/11/83)
3.00 (29/11/83)
PIT LENGTH 2.0
WIDTH 2.0
DEPTH SAMPLE
3.0
DEPTH      SOIL TYPE          DESCRIPTION
0.00
Silty clay     Dark brown grading to dark gray below 0.3 m, silty clay with trace of subrounded gravel and cobbles of basaltic composition up to 15 cm m size, stiff,
greasy to gritty texture, hete- rogenous, moist, highly plastic. slight organic odor and organic
roots to 0.3 m
•TYPE         NO.         SIZE       DEPTH        qu_
Imml        (m)
GQ                1            Bulk       0.20
to
1.00
0.50                 1.75 1.00               1.40
GS                2            Bulk       0.30 to 1.05
1.35 Weathered Light gray, fine grained basalt,
basalt
3.00 
with phenocrysts of plagioclase, vesicular up to 2.0 m, moderately weak to moderately strong, highly weathered grading to moderately weathered toward bottom, highly permeable (possibly top of flow considerably weathered)
Bottom of test pit
Mote:        1 - The walls of the pit were stable and
‘
almost vertical.
2 - No sign of any collapse of the walls
observed during logging on November 29, 1983.
sampling method
SHIPPI
NG CONTAINER
•g _ tnm wall tuoe
0 - tUOe
s -
piartic oag
G - rnovei
P - tin
T-
me tai  n
a
n - carved diocm
Q - giais i«r
U-
woootn box
R - dotn oag
z -
qu unconfined compressive strength
• n xg/cm^ measured with pocket penetrometer
A
<J saroxj
imspfctoR Sevoum
Lemma
NT 0
n
approved
LOGGED p. Valliappan, Saia Monammed DATE De cemoer 1983
form 314 A : ,Test Pit Report
JOB P6888 PIT RJD-4 SHEET 1 OF 1
CLIENT          Ethiopian Electric Light and Power Authority PROJECT Aleltu Hydro Project
LOCATION LATITUDE            See Robi Jida Geoloov Drawing CONTRACTOR       Local labor
METHOD OF
EXCAVATION        Hand dug with shovel and pick WEATHER               Sunny and clear ELEVATIONS: DATUM         MSL
GROUND SURFACE 2,554.25 ROCK SURFACE 2,553.75
PIT LENGTH                2.0
WIDTH 2.0
'DEPTH        SOIL TYPE           DESCRIPTION
(EELPA)
SITE Robi Jida - Right Bank
DEPARTURE
STARTED 08:30               10/11/83
FINISHED 17:10               10/11/83 TEMPERATURE
BOTTOM OF PIT 2,553.25
WATER LEVEL Not encountered
DEPTH 1.0
SAMPLE
•TYPE        NO.        SIZE       DEPTH      qu — - —
(mm)       (m)
0.00
Silty clay
Dark gray silty clay with trace
GZ
1
Bulk
0.00
of subrounded gravel and cobbles
to
of basaltic composition up to
0.50
20 cm in size, medium stiff,
greasy to gritty texture, hete rogenous, moist, highly plastic, slight organic odor and organic roots to 0.3 m
0.50              Weathered              Light gray, fine grained
basalt
1.00
aphanitic with pnenocrysts of plagioclase and pyroxene, moder ately weak and moderately weathered at the top becoming strong and faintly weathered at the bottom of the pit, columnar jointed with size of blocks ranging from 10 to 25 cm Bottom of test pit
Note:         Unable to dig with hand tools below 1.0 m.
SAMPLING METHOD
*8 - thin wall (uM
G — move i
m - carved oiocm
SHIPPING CONTAINER
0 - tuoa
P - tin
Q — glass i«r
A - doth oag
S - pUstic sag
T - ma tai can
U - wooaan Dox
Z - d icaraea
qu unconfined compressive strength
•n <g/cm2 measured with pocKat penetrometer
INSPECTOR Sevoum Lemma --------------------------------------------- LOGGED p. Valliappan, Said Mohammed
APPROVED
DATE ___ norrhor 1QQ?
/
Form 314 A ilTest Pit Report
JOB P6888 PIT RJD-5 SHEET 1 OF 2
CLIENT Ethiopian Electric Light and Power Authority PROJECT Aleltu Hydro Project
LOCATION : LATITUDE See Robi Jida Geology Drawing CONTRACTOR Local labor
METHOD  OF
7/11/83
EXCAVATION
Hand dug with shovel and pick
WEATHER                Sunny ELEVATIONS:   DATUM
GROUND SURFACE ROCK SURFACE
and clear
MSL
2,562.28
2,560-93
(EELPA)
SITE Robi Jida - Right Bank DEPARTURE
STARTED 09:45 
FINISHED 17:10 10/11/83 TEMPERATURE BOTTOM OF PIT 2,559.28
WATER LEVEL 2.70 (10/11/83)
3.00 (29/11/83)
PIT LENGTH
2.0
WIDTH
2.0
DEPTH
3.0
DEPTH        SOIL TYPE            DESCRIPTION
SAMPLE
•TYPE NO. SIZE DEPTH qu_
Imml
(m)
0.00
Silty clay     Dark brown grading to dark gray below 0.3 m, silty clay with trace of subrounded gravel and cobbles of basaltic composition up to 15 cm in size, stiff,
greasy to gritty texture, hete- rogenous, moist, highly plastic.
GQ                 1             Bulk       0.20
to
1.00
0.5C                   1.75
1.00 GS                 2             Bulk       0.30
to 1.05
1.40
slight          organic          odor          and          organic roots to 0.3 m
1.35             Weathered               Light gray, fine grained basalt,
basalt
3.00 
with phenocrysts of plagioclase. vesicular up to 2.0 m, moderately weak to moderately strong, highly weathered grading to moderately weathered toward bottom, highly permeable (possibly top of flow consideranly weathered )
Bottom of test pit
Note:          1 - The walls of the pit were stable and
almost vertical.
2 - No sign of any collapse of the walls observed during logging on November 29,
sampling method
SHIPPING CONTAINER
•g — mm well tuoe
0 — tube
S - plastic o*q
G _ jnovei
P — tin
T - metal can
H — carved oiocx
1983.
qu unconfined comprewve Strength
• n <g/cm^ measured with oocnex penetrometer
Q — glass jar
U — wooden oom
R — doth oag
2     — U scaraea
INSPFCTOR Seyoum
Lemma
LOGGED p, Valliapcan Said Monammed
Form 31 J A 1 •■
Test Pit Report
JOB P6888
P’T RJD-5 SHEET 2 OF 2
DEPTH SOIL TYPE DESCRIPTION
SAMPLE
"TYPE
NO.        SIZE DEPTH (mm) (m)
qu
Note:          3 - Groundwater started seeping from 2.6 m.
4 - Pit wet and saturated at the bottom during logging on November 29, 1983.
Porm 314 A 2Test Pit Report
JOB P6888
PIT RJD-6 SHEET 1 OF 1
CLIENT         Ethiopian          Electric          Light          and          Power          Authority 
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Robi Jida Geology Drawing CONTRACTOR       Local labor
METHOD OF
EXCAVATION         Hand dug with shovel and pick
WEATHER              Sunny and clear
ELEVATIONS: DATUM MSL
(EELPA)
SITE Robi Jida - Right Bank DEPARTURE
STARTED 08:00 
FINISHED 16:10 TEMPERATURE BOTTOM OF PIT 2,580.91
9/11/93 10/11/83
GROUND SURFACE
ROCK SURFACE
PIT LENGTH 2.0
2,581.61
2,581.11
WATER LEVEL Not encountered
WIDTH 2.0
depth
0b7
DEPTH
0.00
SOIL TYPE         DESCRIPTION
Silty clay                 Dark brown grading to dark gray silty clay with trace of sub rounded gravel and cobbles up to 20 cm in size, greasy to gritty texture, highly plastic, slight organic odor and organic roots to 0.2 m
SAMPLE
•TYPE NO.
GZ                 1
SIZE       DEPTH       qu_ (mmi        (m)
Bulk         0.00 to 0.50
0.50
Weathered basalt
0.70
Light gray, fine grained basalt, vesicular, vesicles partially 
filled with yellowish weathered material, moderately strong to very strong, moderately weathered to faintly weathered with depth, columnar jointed with block sizes ranging from 20 to 40 cm
Bottom of test pit
Note: Unable to dig with hand tools below 0.70 m
SAMPLINC METHOD
SHIPPING CONTAINER
*8 — tnm wvall tuoa
0-
tuoa                    S — plastic baq
G - shovei
p-
tin                          T - matai an
m - carvea oioc*
qu uncontinea comprassiva strengtn
• n cm* rraasuraa with pockat panwtromarar
Q-
giau jar
U - wooam ook
R-
doth Dag             Z — u sardea
INSPECTOR Sevoum
Lemma
LOGGED P. Valliappan, Said Mohammed
APOROVED DATE
c prm 314 A 1'Test Pit Report
JOB P6888 PIT TP-100 SHEET 1 OF 1
CLIENT            Ethiopian Electric Light and Power Authority
PROJECT LOCATION
Aleltu Hydro Project
LATITUDE See Impervious Borrow Area Drawing
(EELPA) SITE Jima DEPARTURE
Impervious Borrow
Are.
CONTRACTOR       Local labor METHOD OF
EXCAVATION
Hand     dug     with     shovel     and     pick     and     hand 
STARTED
FINISHED
09:20
16:30
18/11/83
19/11/83
WEATHER
auger
Sunny
ELEVATIONS:  DATUM GROUND SURFACE ROCK SURFACE
and clear
MSL
2,603.72
Not encountered
TEMPERATURE BOTTOM OF PIT 2,599.12 WATER LEVEL       2.4
PIT LENGTH
2.0
WIDTH
2.0
OEPTH 2.5 2.5
SAMPLE
(test Pit) to 4.6 (auger hole)
DEPTH       SOIL TYPE           DESCRIPTION
•TYPE        NO.        SIZE (mm)
DEPTH       qu_
0.00
Silty clay      Dark brown grading to dark gray oelow 0.3 m, stiff, greasy to floury texture, homogenous. moist, highly plastic, slight organic odor and organic roots to 0.4 m, trace of white
partially weathered fragments of basalt up to 3 cm in size
1.4C             Silty clay                Light gray silty clay to clayey
with
silt with some partially
weathered               weathered white suorounded
fragments of basalt
basaltic fragments up to 4 cm in size, stiff, greasy to granular texture, homogenous, moist becoming wet with depth,
GQ               1            3ulk      0.20
to
1.00
0.50              1.75 GS               2           Bulk      0.20
to
1.00
1.00             1.35
GR               3           Bulk       1.40
to
4.60
1.50              1.50
medium
plastic
4.60
Bot tom
of test pit
Note:          1
-    Pit extended by
augering below 2.5
2   -    Observed tension cracks and caving
m.
of
walls      up      to      1.4      m      during      logging  on November 25, 1983.
sampling methoo
’S - thin wall tuoe
G - shovel
m - carved bloc*
INSPECTOR Seyoum Lemma
shipping container
0 - tube
P - tin
Q - glass iar
A - doth bag
s    -   panic bag
qu  unconTineo
compressive strengtn
T-
U-
2-
mcui can
wooden pox
J saroed
•n xg/cm2
measured with pocxet penetrometer
LOGGED
P. Valliappan, Said Mohammed
approved OATE Decembe
Form 314 A , 1 .Test Pit Report
CLIENT          Ethiopian           Electric           Light           and           Power           Authority 
PROJECT Aleltu Hydro Project
LOCATION : LATITUDE See Impervious Borrow Area Drawing CONTRACTOR      Local labor
METHOD OF
JOB P6888
PIT TP-101 SHEET 1 OF 1
(EELPA)
SITE Jima Impervious Borrow Aree DEPARTURE
EXCAVATION
WEATHER
Hand dug with shovel and pick and hand auger
Sunny and clear
STARTED 09:25
FINISHED 16:30 TEMPERATURE
18/11/83
19/11/83
ELEVATIONS: DATUM       MSL GROUND SURFACE        2,604.91 ROCK SURFACE        Not encountered
PIT LENGTH
DEPTH
2.0
SOIL TYPE
WIDTH              2.0 
BOTTOM OF PIT            2,602.41 WATER LEVEL 2.30
DEPTH 2.0 (test pit)
2.0 to 2.5 (auger hole)
SAMPLE
DESCRIPTION
•TYPE         NO.         SIZE       DEPTH
qu_
0.00                    Silty clay           Dark brown grading to dark gray below 0.3 m, very stiff becoming
stiff with depth, greasy to
floury texture, homogenous.
moist, highly plastic, slight organic odor and organic roots
up to 0.4 m, trace of white
partially weathered fragments of basalt to 2 cm in size
(mm)      (m)
GQ                 1             Bulk       0.20
to
1.00
0.50                3.8 1.00               2.5
GO                 2             Bulk        1.00 to 2.00
GR                 3             Bulk
1.50 0.40 to
1.60
2.1
1.60            Silty clay                 Light gray silty clay to clayey
with
silt with some partially
weathered            weathered white sub rounded
fragments
basaltic fragments up to 4 cm
GR                 4           Bulk        1.60
to
2.50
2.00                1.9
2.50
Note: 1
of basalt              in size, stiff, greasy to granular texture, homogenous, moist becoming wet with depth, medium plastic
Bottom of test pit
-    Pit extended by
augering De low 2.0 m.
2   -    Observed tension cracks on the walls of the test
pit
up
to
sampling
method
1.6 m during logging on November 25, 1983.
SHIPPING CONTAINER
O - tuoe
P — tin
Q — glass jar
R - doth bag
s
T
U
z
strength
inspector LOGGED
Sevoum Lemma
P. Vailiappan, Said Mohammed
APPROVED
DATE December 198 3Test Pit Report
JOB
PIT
P6888
TP-100
SHEET 1 OF 1
CLIENT PROJECT LOCATION
Ethiopian Electric Light and Power Authority Aleltu Hydro Project
LATITUDE See Impervious Borrow Area Drawing
(EELPA) SITE Jima DEPARTURE
Impervious Borrow Ared
CONTRACTOR       Local labor METHOO OF
EXCAVATION
Hand     dug     with     shovel     and     pick     and     hand 
STARTED
FINISHED
09:20
16:30
18/11/83
19/11/83
WEATHER
auger
Sunny
ELEVATIONS:  DATUM GROUND SURFACE ROCK SURFACE
and clear
MSL
2,603.72
Not encountered
PIT LENGTH
2.0
WIDTH
2.0
TEMPERATURE BOTTOM OF PIT 2,599.12 WATER LEVEL       2.4
DEPTH 2.5 (test pit)
2.5 to 4.6 (auger hole)
SAMPLE
DEPTH       SOIL TYPE           DESCRIPTION
•TYPE        NO.        SIZE      DEPTH
21
Immi
-(»>
0.00
Silty clay     Dark brown grading to dark gray below 0.3 m, stiff/ greasy to floury texture, homogenous. moist, highly plastic, slight organic odor and organic roots to 0.4 m, trace of white
partially weathered fragments of basalt up to 3 cm in size
1.40             Silty clay                Light gray silty clay to clayey
with
silt with some partially
weathered               weathered white subrounded
fragments of basalt
basaltic fragments up to 4 cm in size, stiff, greasy to granular texture, homogenous, moist becoming wet with depth, medium plastic
GQ              1            Bulk     0.20
to
1.00
0.50               1.75 GS              2            Bulk     0.20
to
1.00
1.00               1.35
GR              3            Bulk      1.40
to
4.60
1.50               1.50
4.60
Note:
1  - Pit extended by
of test pit
Bottom
augering below 2.5
2   - Observed tension cracks and caving
m.
of
walls      up      to      1.4      m      during      logging  on November 25, 1983.
sampling methoo
*8 - thin wall tupe
G - snovei
M — carvaa oiock
INSPECTOR Seyoum Lemma
shipping container
0     - tube
P — tin
Q - gms i«r
R - doth peg
S-
T-
U-
z -
Qu unconfmea comprewve strength
measure a with pocnet penetrometer
LOGGED
P. Vaillappan, Said Mohammed
APPROVED
DATE Decembe j\-il983
Form 314 A 1 |Test Pit Report
CLIENT
PROJECT
LOCATION
Ethiopian Electric Light and Power Authority Aleltu Hydro Project
LATITUDE See Impervious Borrow Area Drawing
JOB       p6888
PIT       TP-101 SHEET 1 OF 1
(EELPA)
SITE Jima Impervious Borrow Area
departure
CONTRACTOR
METHOD OF
EXCAVATION
WEATHER
Local labor
Hand  dug  with  shovel and  pick  and  hand 
STARTED 09:25
18/11/83
aucer
Sunny
ELEVATIONS: DATUM
GROUND SURFACE
and clear MSL 2,604.91
FINISHED 16:30 19/11/83
TEMPERATURE
BOTTOM OF PIT 2,602.41
WATER LEVEL         2.  30
ROCK SURFACE
PIT LENGTH 2.0
Not
encountered
WIDTH
2.0                          DEPTH
2.0
2.0
(test pit)
to 2.5 (auger hole)
SAMPLE
DEPTH
SOIL TYPE
DESCRIPTION
•TYPE
NO.
SIZE
(mm)
DEPTH
(mJ
qu
0.00
Silty clay
Dark brown grading to dark gray
GC
1
Bulk
0.20
below 0.3 m, very stiff becoming stiff with depth, greasy to floury texture, homogenous. moist, highly plastic, slight organic odor and organic roots up to 0.4 m, trace of white partially weathered fragments
of basalt to 2 cm in size
to
1.00
0.50                  3.8 1.00                  2.5
GO                2             Bulk        1.00 to 2.00
1.50 0.40 to
1.60
2.1
GR                 3             Bulk
1.60              Silty clay                 Light gray silty clay to clayey
GR                 4             Bulk        1.60
with
silt with some partially
to
weathered
weathered white subrounded
2.50
fragments
basaltic fragments up to 4 cm
2.00
1.9
of Dasalt
in size, stiff, greasy to 
granular texture, homogenous,
moist becoming wet with depth,
medium
plastic
2.50
Note: 1
Bottom       of test pit
-    Pit extended by
auger mg oelow 2.0 m.
2   -   Observed tension cracks on the walls of the test
pit
up
to
1.6 m during logging on November 25, 1983.
SAMPLING    method
SHIPPING CONTAINER
•B — thin wail tube G - snovei
O - tub«
P - tin
strength
H — carved bloc*
qu unconf inea
m kg/cm
Q — giau )«r
R - cloth OAq
S
T
U
z
INSPECTOR
Sev
oum
Lerma
APPROVED
LOGGED
P.
Vallx
appan, Said Mo
nammed
DATE
Form 31 4 A 111Test Pit Report
JOB P6888
PIT TP-102 SHEET 1 OF 1
CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUOE See Impervious Borrow Area Drawing DEPARTURE
SITE Jima Impervious Borrow Area
CONTRACTOR
METHOD OF
EXCAVATION
WEATHER
ELEVATIONS.
Local labor
Hand dug with shovel and pick
Sunny
DATUM
and clear MSL
2/606.49
18/11/83 19/11/83
2/604.49
GROUND SURFACE
STARTED 09:35
FINISHED 14:00 TEMPERATURE BOTTOM OF PIT WATER LEVEL 1.30
ROCK SURFACE
TRENCH LENGTH
Not
2.0
encountered
See Notes 1
WIDTH         2.0
DEPTH
2.0
SAMPLE
DEPTH
0.00
SOIL TYPE          DESCRIPTION
Silty clay                  Dark brown grading to dark gray below 0.3 m, stiff becoming medium stiff with depth, greasy to floury texture, homogenous, moist, highly plastic, slight organic odor and organic roots to 0.4 m
•TYPE
NO.
SIZE
(mm)
DEPTH im^
GQ
1
Bulk
0.20
to
1.00
0.50
GR
2
Bulk
0.20
to
1.00
1.00
1.10
Silty clay
to clayey
GS
3
Bulk
1.10
to
silt
Light gray silty clay to clayey silt, stiff, greasy to floury texture, homogenous, moist becoming wet with depth, highly plastic, occasional fragments
of partially weathered basalt toward bottom
Bottom of test pit
1.30
GQ
4
Bulk
1.10
to
1.30
1.50
2.00
Note: 1 2 3
Unable to excavate below 2.0 m because
of seepage and accumulation of ground water.
Observed          tension          cracks          on the      test      pit     up     to      1.0      m
on Novemoer 25
/ 1983.
Water
collected in rhe pit
tne walls of during logging is very clear.
sampling method
SHIP°ING CONTAINER
*9 — thin wall tuee G - shovel
O — tuoe
P - tin
m - orvec block
S
T
U
DUPiC osg matai an
qu
Q — giau tar
wooaen box
unconfjnaa comoresjjvs sxrengtn
^•surea with pocket penetrometer
R - cloth naq
z
duardea
INSPECTOR LOGGED
Seyoum Lemma
APPROVED
P. Valliappan, Said Monammed DATE DecemberTest Pit Report
JOB P6888 PIT TP-103 SHEET 1 OF 1
CLIENT PROJECT
Ethiopian Electric Light and Power Autnority (EELPA) Aleltu Hydro Project
SITE Jima Impervious Borr
Area
LOCATION LATITUDE See Impervious Borrow Area Drawing     DEPARTURE
CONTRACTOR                 Local labor
METHOO OF
EXCAVATION Hand dug with shovel
and pick
WEATHER
Sunny and clear
ELEVATIONS: OATUM   MSL GROUND SURFACE     2,608.74 ROCK SURFACE           2,607.64
TRENCH LENGTH            2.0 
WIDTH           2.0
STARTED 14:15              19/11/83
FINISHED 12:00             22/11/83 TEMPERATURE
BOTTOM OF PIT           2,606.74 WATER LEVEL              1.80
DEPTH          2.0 SAMPLE
DEPTH       SOIL TYPE         DESCRIPTION
0.00 Silty Dark brown grading to dark gray
clay
below 0.3 m, very stiff becoming stiff witn depth, greasy to
floury texture, homogenous, moist, highly plastic, slight organic
odor and organic roots to 0.4 m
•TYPE        NO.         SIZE       DEPTH       qu
(mm)      Im}
GQ             1            Bulk       0.20
to
1.00
0.50                3.5 1.00                1.3
GS             2            Bulk       0.30 to
1.10
1.10
Weathered
Light gray highly to completely
GZ
3
Bulk
1.10
basalt
weathered basalt with subangular
to
to subrounded fragments up to
1.80
15     cm     in     size,     weak     to     very 
weak,
moderate to highly permeable
2.00 
3ottom of test pit
Note: Unable to dig with hand tools below 2.0 m.
SAMPLING METHOO
SHIPPING CONTAINER
*3 — rmn wall tuoa
G - $novei
h - carv«a oiock
0 - tuba
P - tin
Q - glass jar
S - plastic oag
T - matai can
U - woooan oox
Pu unconfmaa compressivf strangth
• n <g,cm2 maasurwo with pocxat panetromatar
R - aotn oag               Z - aiscaraed
A
.MCPFCTOR SeyOurn                       Lemma
OGGED p- ValliaPPan* Said Mohammed
A
APPROVED
DATE Dec emo er
Form 314 A llTest Pit Report
JOB P6888
PIT TP-102
SHEET 1 OF 1
CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Impervious Borrow Area Drawing DEPARTURE CONTRACTOR        Local labor
METHOO  OF
EXCAVATION
WEATHER
ELEVATIONS.
Hand dug with shovel and pick
Sunny
DATUM
GROUND SURFACE
and clear MSL 2,606.49
ROCK SURFACE
TRENCH LENGTH
Not
2.0
encountered
WIDTH
2.0
DEPTH       SOIL TYPE          DESCRIPTION
0.00
Silty clay      Dark brown grading to dark gray oelow 0.3 m, stiff becoming medium stiff with depth, greasy to floury texture, homogenous, moist, nignly plastic, slight organic odor and organic roots to 0.4 m
SITE Jima Impervious Borrow Area
STARTED 09:35               18/11/83
FINISHED 14:00               19/11/83
TEMPERATURE
BOTTOM OF PIT 2,604.49
WATER LEVEL 1.30
See Notes 1 and 3 DEPTH 2.0
SAMPLE
•TYPE          NO.         SIZE       DEPTH       qu
——
imml       (m/ GQ                1            Bulk       0.20
1.10              Silty clay                  Light gray silty clay to clayey
to clayey
silt
2.00
silt, stiff, greasy to floury texture, homogenous, moist becoming wet with depth, highly plastic, occasional fragments
of partially weathered basalt toward bottom
Bottom of test pit
to
1.00
0.50                  1.10
GR                2             Bulk       0.20
to
1.00
1.00                  0.75 GS                 3            Bulk       1.10
to
1.30
GQ                4            Bulk       1.10
to
1.30
1.50                1.55
Note:          1 - Unable to excavate below 2.0 m because
of        seepage        and        accumulation        of        ground water.
2   - Observed tension cracks on the walls of
the      test      pit      up      to      1.0      m      during      logging on November 25, 1983.
3   - Water collected in the pit is very clear.
sampling method ‘3 — thin wail xuD«
SHIP°ING CONTAINER
□     — ruoa
G - shovwi
h - carved dock
P — tin
S — planic oag
T — rneial can
□     - 3  lais jar A — doth oaq
U — wooden Dox Z — discarded
qu unconfinto comp revive jtrangtn
•n <g,cm2 maasurao with pocxet penetrometer
INSPECTOR
Sevoum
lemma
APPROVED
LOGGED
P. Valliapp
an, Said Mohamm
ed
1 E De cember 19 3Test Pit Report
Bii
JOB pease PIT TP-103 SHEET 1 OF 1
CLIENT
PROJECT
Ethiopian Electric Light and Power Authority (EELPA) Aleltu Hydro Project
LOCATION LATITUDE See Impervious Borrow Area Drawing DEPARTURE CONTRACTOR                 Local labor
METHOD OF
EXCAVATION Hand dug with shovel
and pick
WEATHER
Sunny and clear
ELEVATIONS: DATUM   MSL GROUND SURFACE     2,608.74 ROCK SURFACE           2,607.64
TRENCH LENGTH            2.0 
SITE J^a Impervious Borrow Area STARTED 14:15 19/11/93
FINISHED 12:00             22/11/83 TEMPERATURE
BOTTOM OF PIT           2,606.74 WATER LEVEL             1.80
WIDTH           2.0
DEPTH       SOIL TYPE         DESCRIPTION
0.00 Silty Dark brown grading to dark gray
DEPTH          2.0
SAMPLE
•TYPE        NO.         SIZE (mm)
OEPTH (mJ
qu_
GQ             1            Bulk       0.20
clay
below 0.3 m, very stiff becoming stiff with depth, greasy to
floury texture, homogenous, moist, highly plastic, slight organic
odor and organic roots to 0.4 m
1.10            Weathered             Light gray highly to completely
to
1.00
0.50                3.5 1.00                1.3
GS             2            Bulk       0.30 to 1.10
GZ             3            Bulk       1.10
basalt
weathered basalt with subangular
to
to subrounded fragments up to
1.80
15     cm     m     size,     weak 
to     very     weak,
moderate to highly permeable
2.00 
Bottom of test pit
Note: Unable to dig with hand tools below 2.0 m.
SAMPLING METHOO
•g — tmn wall tuo*
G - snovei
M — carved oiocx
SHIPPING CONTAINER
0 - tuoe
P - tin
s-
T-
Q - glass iar
U-
R - aotn bag
z -
plastic bag
metai can
woooen dox
disoraed
Qu unconfmec compressive strengtn
•n <g.cm^ measured with pocxet penetrometer
mcppctor Seyoum            Lemma
APPROVED
logged
p. Valliappar., Said Mohammed
xjTest Pit Report
JOB PIT SHEET
P6338 TP-104
1 OF 1
CLIENT Ethiopian Electric Light
PROJECT Aleltu Hydro Project
and Power Authority
(EELPA)
SITE
Impervious Borrow Ared
LOCATION . LATITUDE See Impervious
Borrow Area Drawing
DEPARTURE
CONTRACTOR
Local labor
STARTED       13:00 
23/11/83
METHOD OF
EXCAVATION       Hand dug with shovel
and pick and hand
FINISHED       14:30
24/11/83
WEATHER
auger
Sunny and clear
TEMPERATURE
ELEVATIONS: DATUM
MSL
BOTTOM OF PIT
2,602.54
GROUND SURFACE         2,604.34
WATER LEVEL
Not encountered
ROCK SURFACE       Not
encountered
PIT LENGTH
2.0
WIDTH 2.0
DEPTH 1.5 (test
pit)
DEPTH       SOIL TYPE           DESCRIPTION
0.00              Silty clay                Dark brown grading to dark gray
below 0.3 m, very stiff, greasy
to floury texture, homogenous.
mcist, highly plastic, slight
organic odor and organic roots
to 0.4 m, trace of white
partially           weathered           coarse           sand size fragments of basalt
1.10             Silty clay                Light gray silty clay to clayey
1.5 to 2.3 (auger hole) SAMPLE
•TYPE        NO.        SIZE (mm)
DEPTH      51
with
of basalt
weathered
weathered white subrounded
to
fragments
basaltic fragments up to 2 cm
silt with some partially
in size, very stiff, greasy to granular texture, homogenous, moist becoming wet with depth,
GQ               1           Bulk      0.20
to
1.10
0.50                2.50 GS               2           Bulk      0.20
to
1.10
1.20                2.25
GS                3           Bulk       1.10
2.30
medium
2.30
Note:
Bottom
1 - Pit extended by
plastic
of test pit
augering below 1.5 m.
2 - Observed tension cracks on the walls
of the test pit up to 1.0 m during
logging      on November      28, 1983.
SAMPLING METHOD
SHIPPING CONTAINER
*8 - thin wall tube
G - shovel
0 - tuba
P — tin
S - plastic bag
T — matai an
Qu unconfmed
• n kg/cm2
strength
H - carved oiock
Q - glass jar R - doth beg
U - wooden box Z - d-scanted
INSPECTOR
Seyoum
Lemma
LOGGED
?. Valliapp
an, Said
Monammed
APPROVED
DATE
Form 314 A»1)Drilling Report
JOB P6888
HOLE AH-105
SHEET 1 OF 1
CLIENT
PROJECT
SITE
Ethiopian Electric Light and Power Authority Aleltu Hydro Project
Jima Impervious Borrow Area
(EELPA)
CONTRACTOR       Local labor
09:30  23/11/83
15:00  23/11/83
METHOD OF
DRILLING:
LOCATION:
SOILAugermg  with  post hole
ROCK Not encountered
STARTED
FINISHED
auger CASING Di AM
CORE DIAM
LATITUDE
)
)
See Imoervious
ELEVATIONS: DATUM
DRILL PLATFORM
MSL
DEPARTURE
Borrow Area Drawing
8EARING
INITIAL DIP
90 deg
OTHER  DIPS
GROUND SURFACE 2,605.40 ROCK SURFACE Not encountered BOTTOM OF HOLE 2,603.00 WATER LEVEL Not encountered
PENE-
SAMPLE
___________________ TRATION
OEPTH
0.00
SOIL TYPE
DESCRIPTION
•TYPE I
NO.
SIZE DEPTH RET'D TEST
1.10
Silty clay
Silty clay to clayey silt
Dark gray silty clay, greasy to floury texture, moist, medium plastic
Light gray silty clay to clayey silt with some partially wea thered coarse sand size fragments of basalt, greasy to floury texture, moist, highly plastic Bottom of auger hole
GZ
1
Bulk 0.30 
to
1.00
GS
2
Bulk 1.10 
to
2.40
2.40
SAMPLING METHOD
•A - split tape
3 _ thin wall tuoe
C - piston sampler
D - care oarrti
SHIPPING    container
E - auger
F — wesn
n
□    tuoe
insert
INSPECTOR Seyoum Lemma
LOGGED BY p, Valliappar., Said Mohammed
Form 3’9 A 1PROJECT Aleltu Hydro Project
SITE Jima
Impervious Borrow Arec
LOCATION LATITUDE See Impervious
Borrow Area Drawing
DEPARTURE
CONTRACTOR
Local labor
STARTED
13:00 
23/11/83
METHOD OF
EXCAVATION       Hand dug with shovel
and pick and hand
FINISHED       14:30
24/11/83
WEATHER
auqer
Sunny
and clear
TEMPERATURE
ELEVATIONS: DATUM       MSL
BOTTOM OF PIT
2,602.54
GROUND SURFACE         2,604.94
WATER LEVEL
Not encountered
ROCK SURFACE       Not
encountered
PIT LENGTH
2.0
WIDTH
2.0
DEPTH 1.5 (test
pit)
DEPTH       SOIL TYPE          DESCRIPTION
0.00             Silty clay               Dark brown grading to dark gray
below 0.3 m, very stiff, greasy
to floury texture, homogenous.
moist, highly plastic, slight
organic odor and organic roots
to 0.4 m, trace of white
partially           weathered           coarse           sand size fragments of basalt
1.10             Silty clay                Light gray silty clay to clayey
1.5 to 2.3 (auger hole) SAMPLE
•TYPE        NO.        SIZE (mm)
DEPTH      21
(m->
with
of basalt
GQ               1           Bulk      0.20
to
1.10
0.50               2.50 GS               2           Bulk      0.20
to
1.10
1.20             2.25
GS                3            Bulk       1.10
weathered
weathered white subrounded
to
fragments
basaltic fragments up to 2 cm
silt with some partially
in size, very stiff, greasy to granular texture, homogenous,
moist becoming wet with depth,
2.30
medium
plastic
2.30
Bottom
Note:         1 - Pit extended by                      augering below 1.5 m.
2 - Observed tension cracks on the walls
of the test pit up to 1.0 m during 
logging        on November 28, 1983.
SAMPLING METHOD
SHIPPING CONTAINER
— thin wall tube
O - tuo«
S-
G - snovei
P — tin
T-
qu uncont.nea cocmopmrapuf»ivwa»si tSretrnegntghth
H - carved Block
Q - gias jar
U-
2
•n kg/cm maawrao with pocket penetrometer
R - doth bag
z -
INSPECTOR Seyoum
Lemma
APPROVED
LOGGED
Valliapoan, Said Mohamme
d
DATE
Form 314 A illDrilling Report
H
JOB P6888
HOLE AH-105
SHEET 1 OF 1
CLIENT          Ethiopian Electric Light and Power Authority
PROJECT Aleltu Hydro Project
SITE               Jima Impervious Borrow Area CONTRACTOR Local labor
(EELPA)
METHOO OF
DRILLING
SOILAugering with post hole ROCK Not encountered
LOCATION:        LATITUDE
DEPARTURE
BEARING
INITIAL DIP OTHER DIPS
) See ImDervious
) Borrow Area Drawing 90 deg
STARTED        09:30 23/11/83
FINISHED        15:00 23/11/83
auger CASING Di AM
CORE OIAM
ELEVATIONS: OATUM
DRILL PLATFORM
MSL
GROUND SURFACE 2,605.40 ROCK SURFACE Not encountered BOTTOM OF HOLE 2,603.00 WATER LEVEL Not encountered
DEPTH      SOIL TYPE     DESCRIPTION
0.00              Silty clay
1.10              Silty clay to clayey silt
2.40
Dark gray silty clay, greasy to floury texture, moist, medium plastic
Light gray silty clay to clayey silt with some partially wea thered coarse sand size fragments of basalt, greasy to floury texture, moist, highly plastic Bottom of auger hole
SAMPLE
•TYPE I  NO. GZ            1
GS            2
PENE- ___________________ TRATION SIZE OEPTH RET'O TEST
Bulk 0.30 
to
1.00 Bulk 1.10 
to
2.40
SAMPLING METHOO
•A — spin tube
3 — tnin            tuoe
C - pisxon ampler
□ - core oarrei
E - auger
F — wash
SHIPPING CONTAINER
N — mien
0 - tune
P — A/ater content tin
R — ciotn oaq
S — piartic nag
Y — core box
INSPECTOR Seyoum Lemma
LOGGED BY p Valliappar., Said Mohammed
Q — glass ,ar
APPROVED
DATE     Decembe
Form 318 A 1 >X Qo5
■
Test Pit Report
CLIENT Ethiopian Electric Light and Power Authority PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Impervious Borrow Area Drawina
JOB P6888
PIT TP-107 SHEET 1 OF 1
(EELPA)
SITE Jima Impervious Borrow Area DEPARTURE
CONTRACTOR
METHOO OF
EXCAVATION
WEATHER
Local labor
Hand dug witn shovel and pick Sunny and clear
ELEVATIONS. DATUM       MSL GROUND SURFACE      2,604.02 ROCK SURFACE           2,602.37
PIT LENGTH             2.0
STARTED 08:20
FINISHED 10:00 TEMPERATURE BOTTOM OF PIT WATER LEVEL
21/11/83
23/11/83
2,601.72
Not encountered
WIDTH 2.0
DEPTH 2.3
SAMPLE
DEPTH      SOIL TYPE          DESCRIPTION
0.00
Silty clay     Dark brown grading to dary gray below 0.3 m, very stiff becoming stiff with depth, greasy to floury texture, homogenous. moist, highly plastic, slight organic odor and organic roots to 0.4 m
•TYPE        NO.         SIZE DEPTH (mm)      (m)
GQ               1           Bulk 0.20
to
1.00 0.50 1.00
GS               2                Bulk 0.40 to
1.60
GQ               3
1.65 Weathered Light gray to pinkish, highly to GZ
4 Bulk 1.70 
basalt
completely weathered oasalt with subangular to subrounded fragments up to 15 cm in size, weak to very weak
Bottom of test pit
Bulk 1.00
to
1.75 1.65
to
2.30
2.30
Note: 1 - Unable to dig with hand tools below 2.3 m.
2 - Observed tension cracks and caving of walls up to 1.5 m during logging on November 25, 1983.
sampling method
— thin wall tube
— shovel
— carved block
SHIPPING CONTAINER
O — tube
P — tin
Q - gun jer
R - aotn bag
S — plastic bag
T — metal can
U — wooden box
Z — d.sarded
qu unconfineo oompreuive strengtn
•n kg/cm^ measured with pocxet penetrometer
INSPECTOR      Sevoum Lemma________________________ LOGGED p, Valliappan. Said Mohammad
Form 314 Ail)Drilling Report
JOB P6888 HOLE AH-108 SHEET 1 OF 1
CLIENT
Ethiopian Electric Light and Power Authority
(EELPA)
PROJECT     Aleltu Hydro Project
Jima Impervious Borrow Area
CONTRACTOR Local labor
METHOD OF
DRILLING:
LOCATION:
SOlLAugering with post hole
ROCK Not encountered
STARTED FINISHED
auger CASING DIAM CORE DIAM
08:30  21/11/83
13:00  21/11/83
LATITUDE ) DEPARTURE ) BEARING INITIAL DIP OTHER DIPS
See Impervious Borrow Area Drawing
ELEVATIONS: DATUM
DRILL PLATFORM
MSL
90 deg
GROUND SURFACE 2,604.08 ROCK SURFACE Not encountered BOTTOM OF HOLE 2,601.18 WATER LEVEL 2.3 m
DEPTH 0.00
SOIL TYPE    DESCRIPTION
SAMPLE
•TYPE I NO. SIZE OEPTH RET’D
PENE TRATION TEST
Silty clay
Dark gray silty clay, greasy to floury texture, moist, highly 
plastic, trace of white partially weathered fragments of oasalt up to 2 cm in size
GS           1
Bulk 0.20 
to1. 00
Silty clay 
with weathered fragments of basalt
Light gray silty clay to clayey silt with some partially wea thered white fragments of basalt up to 2 cm in size, moist becom ing wet with depth, medium plastic
Bottom of auger hole
GZ          2
Bulk 2.15 
to
2.90
SAMPLING  method
A — spilt tUD4
g - tnm well tube
C - piston semoier
□ - core o«rre»
INSPECTOR Seyoum Lemma
SHIPPING CONTAINER
E - auger
r - .vein
gias jir
APPROVED
ciotn oaq
P’emc bag
=or» oox
aisoraea
iI
Mil/
LOGGED BY p. Valliappan, Said Mohammed
OATE
Decembe^ 1983
Form 318 A 1|Test Pit Report
CLIENT Ethiopian Electric Light PROJECT Aleltu Hydro Project LOCATION LATITUDE See Impervious CONTRACTOR        Local labor
METHOD OF
and Power Authority Borrow Area Drawincr
JOB P6888 
PIT TP-10 7 SHEET 1 OF 1
(EELPA)
SITE Jima Impervious Borrow Area DEPARTURE
STARTED 08:20            21/11/83
EXCAVATION
WEATHER
Hand dug with shovel and pick Sunny and clear
ELEVATIONS: DATUM       MSL
GROUND SURFACE
ROCK SURFACE
PIT LENGTH 2.0
2,604.02
2,602.37
FINISHED      10:00 TEMPERATURE BOTTOM OF PIT WATER LEVEL
23/11/83
2,601.72
Not encountered
WIDTH 2.0
DEPTH      SOIL TYPE          DESCRIPTION
DEPTH 2.3
SAMPLE
•TYPE         NO.        SIZE DEPTH
(mm)       (m)
GQ               1          Bulk 0.20
qu_
0.00
Silty clay     Dark brown grading to dary gray
below 0.3 m, very stiff becoming
to
stiff with depth, greasy to
1.00
floury texture, homogenous.
0.50
2.50
moist, highly plastic, slight
1.00
1.50
organic odor and organic roots
GS
2
Bulk 0.40
to 0.4 m
to
1.60
GQ
3
Bulk 1.00
to
1.75
1.65
1.25
1.65             Weathered
Light gray to pinkish, highly to
GZ
4
Bulk 1.70
basalt
completely weathered basalt with subangular to subrounded fragments up to 15 cm in size,
weak to very weak
Bottom of test pit
dig with hand tools below 2.3 m.
to
2.30
2.30
Note: 1 - Unable to
2 - Observed tension cracks and caving of walls up to 1.5 m during logging on November 25, 1983.
SAMPLING METHOD
•S - chin wall tuba
G - shovat
SNIPPING CONTAINER
O - tuba
p - tin
S - plttic bag
T - ma tai can
qu unconfinea compr«sav« strength
m Kg/cm^ measure a with pocket penetrometer
N - carvers bloc*
Q - gun iar
U-
bow
R - doth bag
z “ dscaroao
INSPECTOR
Sevoum
Lemma
LOGGED r, ValliaPC-an. Said Mohammed
Form 314 ADrilling Report
JOB P6888 HOLE AH-108 SHEET 1 OF 1
CLIENT
Ethiopian Electric Light and Power Authority
(EELPA)
PROJECT     Aleltu Hydro Project
Jima Impervious Borrow Area CONTRACTOR Local labor
METHOD OF
DRILLING:
LOCATION:
SOlLAugering with post hole
STARTED FINISHED
auger CASING DIAM CORE DIAM
08:30  21/11/83
13:00  21/11/83
ROCK Not encountered
LATITUDE )
See Impervious
ELEVATIONS; DATUM
MSL
DEPARTURE )
Borrow Area Drawina
DRILL PLATFORM
SEARING
GROUND SURFACE 2,604.08 
INITIAL DIP
90 deg
ROCK SURFACE Not encountered 
OTHER OIPS
BOTTOM OF HOLE 2,601.18 
WATER LEVEL 2.3 m
SAMPLE
PENE TRATION
DEPTH      SOIL TYPE    DESCRIPTION
•TYPE
NO. SIZE DEPTH RET'D
TEST
0.00            Silty                Dark gray silty clay, greasy to clay                 floury texture, moist, highly 
GS
1     Bulk 0.20 
plastic, trace of white partially 
to
1.00
weathered fragments of basalt up 
Silty 
clay 
with weathered fragments of basalt
to 2 cm in size
Light gray silty clay to clayey silt with some partially wea thered white fragments of basalt up to 2 cm in size, moist becom ing wet with depth, medium plastic
Bottom of auger hole
GZ          2
Bulk 2.15 
to
2.90
2.90
sampling method
•A — sp>'( ruoe
g _ mm wall (udi
C - piston sampler
□ - core Dirrei
INSPECTOR Sevoum Lemma
SHIPPING CONTAINER
E - auger
F - .vain
v - nsarr
R-
0 - tuoe
S-
P - water content tin
Y-
Q — gias jar
Cloth 3aq
pianic oag
core pom
auaraec
APPROVED
LOGGED BY p, Valliappan, Said Mohammed
OATE         De
cembe^ 1983
Form 318A 1 ’Drilling Report
JOB P6888 HOLE AH-109 SHEET 1 OF
CLIENT PROJECT
Ethiopian Electric Light and Power Authority
(EELPA)
Aleltu Hydro Pro}ect
SITE
Jima Impervious Borrow Area
CONTRACTOR
Local labor
STARTED
13:00 
21/11/83
FINISHED
17:00 
21/11/83
METHOD OF DRILLING.
LOCATION:
SOIL Augenng with post hole auger CASING DI AM
ROCK Not
encountered
LATITUDE DEPARTURE BEARING INITIAL DIP OTHER  DIPS
)
)
See Impervious Borrow Area Drawing
CORE DiAM
ELEVATIONS: DATUM
DRILL PLATFORM -
MSL
90 deg
GROUND SURFACE 2,605.70 ROCK SURFACE Not encountered BOTTOM OF HOLE 2,603.50 WATER lEVEl 2.0 m
DEPTH 0.00
SOIL TYPE      DESCRIPTION
SAMPLE
•TYPE 1 NO.
SIZE DEPTH RET’D
PENE TRATION TEST
Silty
clay
Silty clay with weathered fragments of basalt
Dark gray silty clay, greasy to floury texture, moist, highly plastic
Light gray silty clay to clayey silt with some partially wea thered white subrounded basaltic fragments, moist becoming with depth, highly plastic Bottom of auger hole
GZ
1       Bulk 0.30 
to
1.00
1.20
GS        2
Bulk 1.20 
to
2.20
wet
2.20
SAMPLING METHOD
•A - split tuOe
3 — tmn well rube
C - piston sampler
□ - core oarrei
INSPECTOR spyoum Lemma
E - auger
r - wasn
SHIPPING CONTAINER
N - i men
0 - xuoe
P - water content tin
Q - gias ar
R    -   ciotn oag
S-
Y-
(
plastic bag
core oox
discs raeo
LOGGED BY p, Valliappan, Said Mohammed
APPROVEO DATE
December'T.983
Form 318 A »1|Drilling Report
JOB P6888 HOLE AH-109 SHEET 1 OF 1
CLIENT
Ethiopian Electric Light and
Power Authority
(EELPA)
PROJECT
Aleltu Hydro Project
SITE
Jima Impervious Borrow Area
CONTRACTOR
Local labor
STARTED
13:00
21/11/83
FINISHED
17:00
21/11/83
METHOO OF
SOIL Augering with post hole
aucerCASING DIAM
DRILLING.
LOCATION:
ROCK     Not encountered
LATITUDE       ) DEPARTURE ) BEARING INITIAL DIP OTHER DIPS
See Impervious Borrow Area Drawing 90 deg
DEPTH 0.00
1.20
SOIL TYPE Silty 
clay
Silty 
clay          with weathered fragments
of basalt
DESCRIPTION
Dark gray silty clay, greasy to floury texture, moist, highly plastic
Light gray silty clay to clayey silt with some partially wea thered white subrounded basaltic fragments, moist oecoming wet with depth, highly plastic Bottom of auger hole
CORE OlAM
ELEVATIONS:     DATUM                           MSL
DRILL PLATFORM -
GROUND SURFACE 2,605.70
ROCK       SURFACE       Not       encountered BOTTOM OF HOLE 2,603.50
WATER LEVEL 2.0 m
PENE- SAMPLE________________________ TRATION
•TYPE NO. SIZE DEPTH RET'D TEST GZ 1 Bulk 0.30 
to
1.00 GS 2               Bulk 1.20 
to
2.20
2.20
SAMPLING METHOD
•A - spilt tube
0 - thin wall !um
C - onton sampler
□ - core carrel
INSPECTOR seyoum Lemma
e - auger
F - wasn
SHIPPING CONTAINER
N - insert
0 - tune
P - water content tin
Q — glass jar
R - ciotn oag
S - plastic nag
V - core box
Z — discarded
—________________
approve°
LOGGED 3V p Valliapoan, Said Mohammed
t
OATE Decemoer^Q 83
Porrn 318 A 111i 0DEID
ACCUMULATION OF BASALT BOULDERS THICK SOIL COVER ,OVER SOcml
THIN SOIL CO/ER I LESS THAN SOcm I WEATHERED BASALT
COLUMNAR JOINTEO BASALT
\ \ \ CLIFF FACE SLUMPING AT BOTTOM ___  GEOLOGICAL CONTACT OBSERVED ___ GEOLOGICAL CONTACT INFERRED
* TEST PIT
prrrg rock outcrop
NOTE
TOPOGRAPHY OBTAINED BY EELPA GROUND SURVEYS DURING PREFEASIBILITY FIELD INVESTIGATIONS IN I98S
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY ALELTU HYDROELECTRIC PROJECT
GEOLOGY OF TILIKU ALELTU DAM SITE
UIBELEVATION IN METRES
ET"»OHAN UtCTMC iK>l ANO *<OWI AuTMCWTt
M’U >
GEOLOGICAL SECTION OF M ZEGA WE Of M GORGE MGA
CLASSIFICATION OF SEDIMENTARY ROCKS
NOTE
JOINT MEASUREMENTS PLOTTED AS DIP AZIMUTH / DIP
SET DIP AZIMUTH DIP
1                   165’           68 345*          90
SPACING I mm i  BEDDING
VERT THINLY LAMINATED
JOINTING
U                  0S4°          87 2 14”         90
i 10
10-100
lOO-IOOO
OVER 1000
MEDIUM BEDDED
THICK MOOED
THINLY TO THICKLY LAMINATED
VERY THIN TO THINLY BEDDED
VERY CLOSE TO CLOSE JOINTED
ID                 065 ’          84 245’           89
MEDIUM JOINTED
WOE JOINTED
U                   282’           80
ETHIOPIAN ELECTRIC LIGHT ANO POWER AUTHORITY ALELTU HVDROELECTW,: pnclmct gagra GEOLOGIC STEREONETS WliFIGURE I
FIGURE 3
FIGURE 4
MAJOR TECTONIC FEATURES
LOCATION OF VOLCANIC CENTRES
LOCATION  OF  SEISMIC  EVENTS  OF MAGNITUDE 4
FIGURE 6
FIGURE 7
FIGURE 5
SOURCE OF INFORMATION
'EAR’HOUAKE   HISTORY   OF   E’HiOPiA   AND   ThE   HORN   OF   AFRICA" BY PIERRE GOU1N
INTERNATIONAL     OEVEuOpMENT     RESEARCH     CENTRE PUBLICATION No ilBE OTTAWA. CANADA 1979
PREDICTED GROUND ACCELARATION
PREDICTED INTENSITY
attenuation CURVES
C5
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY ALELTu HYDROELECTRIC PROJECT
SEISMICITY OF ETHIOPIA   UIBKILOMETRES
LOCATION MAP
SILTY CLAY
-SILTY CLAY WITH WEATHERED    FRAGMENTS
TP-107
OF BASALT
_        -p
I 2615 t
PLAN
SECTION A-A
METRES
SILTY CLAY-,
i SILTY CLAY WITH
WEATHERED FRAGMENTS
OF BASALT
-   2620 g
TP-100 AH-108 TP-101 Art’109
EL 2605?
EL 26024
-----------------
TP-102
EL26O69
-  2610 —
El 26049 El 2603 s
■ —TJT '------ r^~  4
\
EL 26045 /
WEATHERED BASALT
200                   400
600
1400                  1600                  1800
SECTION B-B
PLATE C-6
POTENTIAL JIMA IMPERVIOUS BORROW AREA  M8
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY
ALELTU HYDROELECTRIC PROJECT
AUGER HOLE 108c
oo                  <«
fcOa0
TiME U,NU’ES)
SWELL PRESSURE TEST TIME SWELL CURVE
B
PRESSURE .P ‘   /cn»* » CONSOLIDATION TEST e - Log P CURVE
OIRECT SHEAR TEST FAILURE ENVELOPE
PLASTICITY CHART
NOTE
C"MTT XX, STA0OLS "• "™ '"PCO •** CLASS* CATCH JTSTEM
5
8
i
GRAIN SIZE DISTRIBUTION
LEGEND
----------T»O2
---------r»K»
— - AH 109
IO2-III
ii si
io? ■ ?l ANO TP iOO IOE- lOI
--------- TR iOS
SWEU-iNS »»ES3u £ •«-
o
- ------- AH 109
103- l>
<02 1 II
SWELL CUPVE COR
PARTI ALL* CONFINED SWELL TEST
VARIATION OF UNDRAINED STRENGTH WITH
MOISTURE CONTENT
HORIZONTAL DISPLACEMENT I moil
DIRECT SHEAR TEST
STRESS DISPLACEMENT CURVES
—    - TP IDA
- - ah ior
iii 221
no- SI
--------- TPIOl l
OA KI
MOISTURE CONTENT t%>
---- ----- TP 100
IIO-ASl
STANDARD PROCTOR COMPACTION
TEST RESULTS
--------- AH OS I0S-2H
—  AH 109 - 2 22 I
"LA’E C
ETHIOPIAN ELECTRIC UGHT AND POWEP AUTHORITY AlEl’u HYOROE^ECTRir PwrufCT
PROPERTIES OF IMPERVIOUS MATERIALS
KIESJ
LIQUID LIMIT (%)
PLASTICITY CHART
NOTE
OART AND SYMBOLS ARE CROM UNFIED SOL CLASSIFICATION SYSTEM
1
RlvOlDCuWvE
COBBLES
GRAVEL
SAND
SILT OR CLAY
COAPSE  PINE
(
MEDIUM            PINE
________________ i--------------------
'□ARSE
GRAIN SIZE DISTRIBUTION
X • v
X2
LEGEND
---------------- TP 102  (02-1 •)
---------------to 102  (11-13)
-------------AH 109 (02-12) AND TP 100 (0 2-10)
---------------- TP 103  (03-1 I)
--------------- AH  108  (02-1 I)
--------------- AH  108  (i 1-22)
--------------- TP 104  (10-15)
------------------- TP  101    (04-16)
----------------TP 100  (10-46)
--------------- AH  105 (03-21)
--------------- AH  109 (I 2-22 I
PLATE C
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY
ALELTU HYDROELECTRIC PROJECT
PROPERTIES OF IMPERVIOUS MATERIALSLIQUID LIMIT (%)
PLASTICITY CHART
NOTE
CHART AND SYMBOLS ARE FROM UNIFIED SOL CLASSIFICATION SYSTEM
COBBLES
GRAVEL
SAND
SILT OR CLAY
COARSE ;NE
r
I MEDIUM ] FINE
COARSE
GRAIN SIZE DISTRIBUTION
LEGEND
------------ TP 102 (02-11)
------------- TP 102 (11-13)
-------------- AH 109    (02-12) AND  TP  100  (0  2-10) ------------ TP 103 (03-1.1)
-------------- AH 108 (02-1 I) -------------- AH 108 (1.1-22) ------------ TP 104 (1.0-15) ------------ TP IO» (04-16) -------------- TP 100  (I 0-46' ------------AH >05 (03-21) ------------ AH 109 (12-22)
PLATE C
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY ALElTU HYDROELECTRIC PROJECT
PROPERTIES OF IMPERVIOUS MATERIALSAPPENDIX D
TABLE OF CONTENTS
LIST   OF   TABLES LIST OF PLATES
Page
DI - WORK PROGRAM------------------------------------------------------------------------------  D- 1
D2 - DESCRIPTION OF THE PRESENT SETTING--------------------------------------------  D- 3
D3 - SHORT-TERM IMPACTS DURING CONSTRUCTION---------------------------------  D-18
D4 - LONG-TERM IMPACTS OF PROJECT-----------------------------------------------------  D-19
D5 - COST OF MITIGATING MEASURES------------------------------------------------------  D-26
PLATESAPPENDIX D
LIST OF TABLES
Number           Title
D. 1 Information on Farmer Associations
D.2
School Locations
D. 3
Health Care Services
D.4
Number      and      Percentage
of
Leading 
Causes for HospitalizationAPPENDIX D
LIST OF PLATES
Number    Title
D-l Environmental DefinitionsMay 28, 1984
APPENDIX D
SOCIOECONOMIC AND ENVIRONMENTAL ASSESSMENT
Construction o£ the Aleltu project will have various social
and environmental impacts on the surrounding community. With the extensive development of agriculture in the project area, 
the creation of reservoirs will have a significant impact on the local farmers in the Tiliku Aleltu and Jida basins. The construction of the power tunnel with its access adits and surge chamber, penstock, powerhouse and transmission line will also have an effect on the land use but being confined to smaller areas of impact can be more readily absorbed by the community.
This appendix presents a description of the local setting, identification of the major social and environmental issues, consideration of mitigating measures and identification of issues that should have additional assessment in the feasibility studies.
DI - WORK PROGRAM
As part of tnis study, social and environmental aspects of the project were reviewed. Tne investigation involved a site visit, acquisition of data from government agencies in Addis Ababa, and discussions with local officials and residents.D-2
From the site visit, it was possible to acquire considerable environmental information about the study area. With most of the area being used extensively for agricultural purposes, 
the major environmental issue was identified as being the inundation of grazing land and the resultant effects on the local farmers. Discussions with the local representative from the Ministry of Agriculture and information from the Bureau of Statistics were valuable in addressing this issue.
Contact With
Government Agencies
The main agencies contacted were the
- Planning Commission
(a)       General Statistical Office
(b)      Agricultural Statistics Office
(c)       Cartography Office
(d)       Ministry of Health
(e)       Ministry of Education
- Ministry of              Agriculture, Agriculture           Organization
Discussions were held in Muke Tun with
specifically Food and (FAO).
-   the local Ministry of Agriculture representative
- tne political representative for the Wuchale District
-   the general service representative for the Wuchale District.D-3
Other agencies identified for contact during the feasibility studies to develop detailed agricultural and rehabilitation programs are
-   Ministry of Urban and Housing Rural Project Agency
-   Science and Technology Commission
-   Agricultural and Industrial Development Bank
-   Addis Ababa University.
D2 - DESCRIPTION OF
THE PRESENT SETTING
(a) Land Use
The topography of the area in the vicinity of the proposed reservoirs is in general flat. As a conse quence, the area inundated with even low dams will be signif icant.
In the gorge, the topography is characterized by ver tical cliffs, natural terraces and shallow to steep soil covered slopes.
Within tne proposed project area on the plateau, virtually all tne available land is utilized for agri culture, either for crop cultivation or cattle grazing on natural pasture. In the gorge, the terraces and shallow slopes are farmed.D-4
Most of the people in the area are peasant farmers at
close to subsistence living. Each family farms 3 to 
4 ha, cultivating barley with some beans in the March to August period, and teff, wheat, barley, sorghum, chick 
peas and beans in the September to February period. The Ministry of Agriculture has tried, with little success
yet, to introduce the production of maize in the area. 
The main crops taken to market are barley and beans. Sedentary peasant livestock grazing occurs on unimproved pasture and fallow. Since the land is normally left
fallow for 4 to 10 years subsequent to intense cultiva
tion, considerable area for cattle grazing is available. 
Cattle are maintained for milk and meat. Herd sizes
vary, averaging 4 to 5 cattle per family with maximums
up to 20 cattle per family. Additional livestock 
includes sheep, goats, horses and donkeys. Oxen are maintained by some farmers for ploughing of the fields.
The housing settlement pattern of the farmers on the
plateau is important. The homes are generally in clus
ters, located on high land along the ridges of the
valleys and not down in the valleys. In general, the
houses are of a simple construction, wood pole frame
with thatch roofs and/or stone and mud or thatch walls. 
The land immediately adjacent to the homes is the most intensely cultivated with unimproved pasture occupying a larger proportion of the valleys.
Potable water is acquired from springs located near the homes. These springs are reported to flow even during 
the dry season.* The rivers are used to water the
Reported       by       tne       local       Ministry       of       Agriculture in Muke Turi.
representativeD-5
cattle but, apparently, not as a supply of potable water or for irrigation except in the vicinity of the Agat reservoir. In the Agat reservoir area, there is an 8-km canal, which was initially built for a flour mill in Debre Libanos. At present, it is being used for a very small power plant in the same area and for irrigation purposes along its length. The irrigated land produces mostly onions.
(b) Population
As a result of the recent national census, accurate information on the number of people in the study area is available. The actual location of peasant associations has been mapped by the General Statistical Office and should be finalized and available by March 1984.
Information on the farmer associations, including the names, number of members, major crops and types of animals raised in some of the districts potentially affected by the project, is shown in Table D.l. 
District boundaries are presented on Plate D-l.
The Debre Libanos District, which contains the Agat and Tinishu Aleltu basins, has approximately 6,375 people or 15.7 people per square kilometre. The Wuchale District, located south of the Debre Libanos District, contains
the entire Tiliku Aleltu and part of the Jida reser voirs. Although the Wuchale District nas a population of over 8,800 or 17.4 people per square kilometre, most of the settlements are located in the south and southcentral areas of the district. Population density 
in the area of tne Tiliku Aleltu and Jida reservoirs is sparse.TABLE D.1(a)
INFORMATION ON FARMER ASSOCIATIONS PROVINCE; Selale
DISTRICT:        Debre Libanos
Majoi Kind of Crop              Major
Name of Peasant
Major
Sep to
Mai to
Type of
Association
Member s
Occupation
Feb
Aug
Animals
Climate
Legend
Wayu
372
3
a,b ,c
c
k,l,n
P
1 - farming
Sele
328
3
a,b, c
c
k,l,n
P
2 - raise cattle
Timano
600
3
a,b,c
c
k,l ,n
P
3 - both
Sone
313
3
a f b, c
c
k,l,n
P
Fikre Seiam
Goro Gorone
130
481
3
3
d ,a
a,b
c
c
k ,m,n
k,l,n
Q,R
P
a - teff
b - wheat
Wortu
3 17
3
Kessim
d,b,a
c
k,l,n
P
c - barley
386
3
0
b, a, f
c
k, l,n
P
d - sorghum
Arabona Ayat
131
3
I
cn
a ,d
c
k ,m, n
Q,R
e - chick-pea
Auki Meselal
79
3
a,d,c
c
k, m, n
Q,R
f - beans
Set Debir
52
3
a,d,f
c
k,m,n
Q
g - nug
Zega Amel
149
3
a, d
c
k,m(n
R
Bussa
292
3
d ,a
c
o
P
k - cattle
Doiene
306
3
b,a,f
c
o
P
1 - sheep
Ji jiga
140
3
b,a,f
c
k,l,n
P
m - goats
Adis Alem
229
3
a, d, e
c
kn
Q,R
n - horses/donkeys
Hagere Selam
127
3
a,d,e
c
k ,m, n
Q.R
o - all
Gora Sbemen
229
3
a, b, e
c
o
p
Mukeara
342
3
c ,a
c
k, 1 ,n
p
P - cool zone
Edero
316
3
c, a,b
c
k, 1 ,n
p
Q - temperate zone
Babu Etaya
312
3
b, e
c
o
p
R - hot zone
Verero Aueguta
200
3
b, a, e
c
k,m, n
R,Q
Ji bo
284
3
b,a
c
o
P
Wero
260
3
a,b, c
c
k,l,n
P
TOTAL
6 375TABLE D.1(b)
INFORMATION ON FARMER ASSOCIATIONS
PROVINCE:        Selale
DISTRICT:         Wuchale
Major Kind of Crop              Major
Name of Peasant
Major
Sep to        Mar   to
Type     of
Association
Members
Occupation
Feb
Aug
Animals
Climate
Legend
Mechel a
185
3
c,f ,a
-
k. 1 ,n
P
1 - farming
Bole Gendem
222
3
a (b,c
-
o
Q
2 - raise cattle
Boseke Debir
130
3
a.b.c
-
k,l ,n
p
3 - both
Jibara
269
3
a,b, c
-
k  1  n
ff
p
date
213
3
a.b.c
-
k,l,n
P.Q.R
a - teff
Boseke
142
3
a, b, c
-
k,l,n
p
b - wheat
Duber Guto
180
3
a,b,c
-
k,l ,n
P.Q.R
c - barley
Duber Gebriel
24 1
3
a, b, c
-
k.l.n
p
d - sorghum
Webera
2 15
3
a,b,c
-
k.l.n
p
e - chick-pea
U
I
Tigrenobuko
595
3
a, b, c
-
k,l,n
p
f - beans
Kex eyu
171
3
a, bjC
-
k.l.n
p
g - nug
Adere Gordema
295
3
a, b, c
-
k.l.n
p
Dete Kot a
172
3
a, b, c, d -
k,l,n
p
k - cattle
Beeley Gimbichu
331
3
a, b, c
-
m
p
1 - sheep
Gel im
182
3
a,b,c
-
k.l.n
p
m - goats
Ellu Kora
257
3
a, b, c
-
k,l,n
p
n - horses/donkeys
Ado
2 29
3
a,b,c
-
k,l,n
p
o - all
Asomani
270
3
a, b, c
-
k.l.n
p
Botena Seyu
212
3
a, b,c
-
k,l,n
p
P - cool zone
Gorasa
203
3
a.b.c
-
k.l.n
p
Q - temperate zone
Ayu
196
3
a, b,c
-
o
P.Q
R - hot zone
Egu Kora
150
3
b,c, f
-
k.l.n
p
Babo Bedeyu
304
3
a, b  c f -
r#
o
Q
Deyu Gimbichu
818
3
a,b,c
-
o
QTable D.1(b)
Information on Farmer Associations - 2
PROVINCE:       Selale
DISTRICT:        Wuchale
Maj.or Kind of
Name of Peasant
Association
Members
Major
Occupation
Sep
Feb
to         Mar Aug
C F°P to
Major
Type     of
Animals Climate Legend
Akaku                                           223              3
Enguye Gerdo                              247              3
Adamana Deku                            250              3
Harcho                                          294              3
Becho Fanili                                 464              3
Becho Gorada
a f b g c / f — a,b,c,f
a,b,c,f
a,b,Cjf
a,bfc,f
o
k,l,n
k,l,n
k,l,n
k,    l,n
1  - farming
2  - raise cattle
3  - both
a - teff
247
3
a^bjCjf
o
k,l
b - wheat
Kaso Tulu
253
3
a,b# c,f
,n
c - barley
Nono Kore
376
3
a,b,c,f
k,l,n
k,l,n
d - sorghum
Kaso Aye
2 08
3
a , b t c, f -
e - chick-pea
Nono Boli
293
3
a,b,c,f
o
k,l ,n
f - beans
Mechela Andode
213
3
a t b / c g f —
TOTAL
8 830
g - nug
k - cattle
1 - sheep
m - goats
n - horses/donkeys
o - all
p - cool zone
Q - temperate zone
R - hot zone
I
1
iiTABLE D.1(c)
INFORMATION ON FARMER ASSOCIATIONS
PROVINCE:      Selale
DISTRICT:        Ensaro 
Major Kind of Crop
Name
of
Peasant
Members
173
Major
Occupation
3
Sep to
Feb
c,f ,b
Mar to
Aug
c,f
Major
Type
of
Association
Animals
Climate
Engoyu Arogi
108
263
3
3
c,f ,b
c / f i b
C/f
C/f
k,l,n
k,l,n
P
P
Legend
1 - farming
Tosegn
Ture
k,l,n
k,l,n
P
P
2 - raise cattle
3 - both
Enkuye Felelo
165
180
3
3
c,f ,b
c,f ,b
c,f
c,f
Bidano
Weserbi
91
146
3
3
c,f ,b
c,f ,b
c,f
c,f
k,l,n
k,l,n
P
P,Q,R
a - teff
b - wheat
k,l,n
P,Q,R
Abakasin
186
189
3
1
c,f ,b
c, f / b
c,f
c,f
k /1 / n
p
c - barley
d - sorghum
Esunaeteya
Kasem
Mute
201
194
1
1
c, f,b
c,f ,b
c,f
c,f
k,l
k,l
p
p
e - chick-pea
f - beans
Wekesir
181
302
1
1
b, a, c
b,a,c
c,f
c,f
k,l
k,l
p
Q
Denbana Egersa Leinina Munir
g - nug
k - cattle
Seielanami kerso
314
302
1
1
b, a, c
b,a,c
C/f
c,f
k,l
k,l
Q
Q
k,l
k,l
Q
Q
1 - sheep
m - goats
Kersanabisanera
Anzucha
Gi rarge
214
76
1
1
b, a, c
d, a,c
c,f
c,f
n - horses/donkeys o - all
Wegebnaaimg
176
216
1
1
d, a, c
d / a / c
C,f
C/f
k,l
k,l
R
Q,R
Welencheta Senketan
102
341
3
1
c,f
C/f
C/f
C/f
k,l
k,l,n
Q,R
Q
P - cool zone
Q - temperate zone
R - hot zone
Et nora Kena Amba
336
227
1
1
b,f ,a
b,f ,a
C/f
C/f
k,l ,n
k,l,n
R,Q
R
Hose
248
307
3
3
*/C,g
a,g
C/f
C/f
k,l,n k/1 ,m
R
P
Dawanakodiso
k/l/tn
P
Daugiorgis
217
491
3
3
ac
 # »f t g a,c,f,g
C/f
C/f
k, 1 ,m
P
Awarenabedaek
Digididara
251
260
1
1
a, d
a,d
C/f
C/f
k,l,m
m,k,l
P
R
Chewanamoraja
m,ki 1
m,k, 1
R
Kolamog
113
1
a,d
C/f
RTable D.1(b) Information on Farmer PROVINCE:     Selale DISTRICT:       Wuchale
Associations -
2
Major Kind of Crop Major
Name of Peasant Association
Members
Major
Occupation
Sep
Feb
to
Mar to
Aug
Type    of Animals
Climate
Legend
Akaku
223
3
a f b | c i f
o
Q
1 - farming
Enguye Gerdo
247
3
a,b,c,f
-
k,l,n
p
2 - raise cattle
Adamana Deku
250
3
a t b g c f f
-
k,l,n
p
3 - both
Harcho
294
3
a,b,c,f
-
k,l,n
p
Becho Fanili
464
3
a f b f c / f
-
k,l,n
R
a - teff
Becho Gorada
247
3
a,b,c,f
-
o
Q
b - wheat
Kaso Tulu
253
3
a,b,c,f
-
k,l,n
P.Q
c - barley
Nono Kore
376
3
a,b,c,f
-
*
k, l,n
P.Q
d - sorghum
Kaso Aye
2 08
3
a,b,c,f
k,l,n
p
e - chick-pea
Nono Boli
293
3
a,b,c,f
-
o
Q/R
f - beans
U
I
co
Mechela Andode
213
3
a,b,c,f
k,l ,n
P
g - nug
TOTAL
8 830
k - cattle
1 - sheep
m - goats
n - horses/donkeys
o - all
p - cool zone
Q - temperate zone
R - hot zoneTABLE D.1(c)
INFORMATION ON FARMER ASSOCIATIONS PROVINCE:    Selale
D1STRICT: Enaaro
Name     of     Peasant
Major
Major Kind of Crop Major
Sep to Mar to Type of
Association
Members
Occupation
Feb
Aug
Animals
Climate
Legend
Engoyu
173
3
c,f ,b
c,f
k,l,n
P
1 - farming
Arogi
108
3
c,f ,b
c,f
k,l,n
P
2 - raise cattle
Tosegn
263
3
c,f ,b
c,f
k,l,n
P
3 - both
Ture
165
3
c,f ,b
c,f
k,l,n
P
Enkuye Felelo
180
3
c,f ,b
C,f
k,l,n
P
a - teff
Bidano
91
3
c,f ,b
C, f
k,l,n
P,Q,R
b - wheat
Weserbi
146
3
c,f ,b
c,f
k,l,n
P,Q,R
c - barley
Abakasi n
186
3
c,f ,b
C,f
k,l,n
p
d - sorghum
O
Esunaeteya
189
1
c,f ,b
c,f
k,l
p
e - chick-pea
KO
I
Kasem
201
1
c,f ,b
c,f
k,l
p
f - beans
Mute
194
1
c,f ,b
c,f
k,l
p
g - nug
Wekesi r
181
1
b,a,c
C,f
k,l
Q
Denbana Egersa
302
1
b,a,c
C,f
k,l
Q
k - cattle
Lemina Munir
314
1
b / a f c
c,f
k,l
Q
1 - sheep
Selelanamikerso
302
1
b, a,c
c,f
k,l
Q
m - goats
Kersanabisanera
214
1
b, a,c
C,f
k,l
Q
n - horses/donkeys
Anzucha
76
1
d,a,c
c,f
k,l
R
o - all
Gi rarge
176
1
d,a,c
c,f
k.l
Q,R
Wegebnaaimg
216
1
d,a,c
c,f
k,l
Q,R
P - cool zone
Welencheta
102
3
c,f
c,f
k, 1, n
Q
Q - temperate zone
Senketan
341
1
c,f
C,f
k,l,n
R.Q
R - hot zone
Et nora
336
1
b,f ,a
C,f
k,l,n
R
Kena Amba
227
1
b,f ,a
C,f
k,l,n
R
Hose
248
3
a,c,g
c,f
k,l,m
P
Dawanakodiso
307
3
a,g
C,f
k,l,m
P
Daugiorgis
217
3
a,c,f,g
c,f
k,l,m
P
Awarenabedaek
491
3
a,c,f,g
C,f
k,l,m
P
Di gididara
251
1
a,d
C,f
m,k»l
R
Chewanamoraja
260
1
a,d
C/f
m,k,l
R
Koiamog
113
1
a,d
c,f
n>,k,l
RTable D.1(c)
Information on Farmer Associations - PROVINCE:     Selale
DISTRICT:       Ensaro
2
Major Kind of Crop            Major
Name of Peasant Association
Members
Major
Occupation
Sep to
Feb
Mar
Aug
to
Type of
Animals Climate Legend
Kor go go
340
1
a,d
Shenkora
c,f
m, k, 1
R
1 - farming
452
3
a, d
c,f
m,k,l
R
2 - raise cattle
Harowadeba
296
1
a,d
Harogulele
c,f
m, k, 1
R
3 - both
213
1
a, d
c,f
m,k,l
R
Kekersak i
448
3
a,b,f
c,f
m, k, 1
P
a - teff
Borebornak
283
3
a.b.c
C,f
m.k.l
P
b - wheat
Bikonadibi
366
3
a,b,f
c,f
m,k,l
P
c - barley
Aliberdada
265
3
a,b, f
C,f
m, k, 1
P
d - sorghum
Tulumilke
304
3
a,b,f
-
k,l,n
P
e - chick-pea
Aba Botro
358
3
a,b,f
-
k.l.n
P
f - beans
Jemjem Arbabo
425
3
d ,a
-
k,l,n
R
g - nug
Petona Sekekelo
358
3
d, a
-
k,m, n
R
Bochela
377
3
d ,a
-
k,m,n
R
k - cattle
Bobena Meda
267
3
d, a
-
k,m, n
R
1 - sheep
m - goats
TOTAL
11 322
n - horses/donkeys
o - all
p - cool zone
Q - temperate zone
R - hot zoneTABLE D.1(d)
INFORMATION ON FARMER ASSOCIATIONS PROVINCE:    Selale
DISTRICT: Girar Jersa
Major Kind of Crop            Major
Name     of     Peasant
Major
Sep to           Mar  to
Type    of
Associ at ion
Members
Occupation
Feb
Aug
Animals
Climate
Legend
Arje Gideyu
4 16
3
c,b,f
c,f
k,l ,n
P
1 - farming
Alamo Denka
266
3
c,b; a
c,f
k,l,n
P
2 - raise cattle
Selala Ali
183
3
c / b t a f f
c,f
k,l ,n
P
3 - both
Ana Chare
304
3
c,b,a,f
c,f
k,l,n
P
Bowana
2 39
3
c t b f a ( f
c,f
k,l,n
P
a - teff
Kano
371
3
c i b / a t f
c,f
k,l,n
P
b - wheat
Ameto
165
3
C;b,a,f
c,f
k,l,n
P
c - barley
Eras Osmani
363
3
c,b,a,f
-
k,l,n
P
d - sorghum
Eras Kino
250
3
c,b,a,f
-
k,l,n
P
e - chick-pea
Gishe Merche
272
3
c,b,a,f
-
k,l,n
P
f - beans
Sobo Abote
191
3
c,b,a,f
c,f
k,l,n
P
g - nug
Enta Denka
232
3
c,b,a,f
C|f
k,l,n
P
Etiso Boli
301
3
c,b,a,f
c,f
k,l,n
P
k - cattle
Shire Raso
258
3
c,b,a,f
C,f
k, l,n
P
1 - sheep
Setane Weldami
233
3
c t b f a i f
-
k,l,n
P
m - goats
Wert e
262
3
c,b,a,f
-
k,l,n
P
n - horses/donkeys
Enate Deneba
531
3
c / b t a / f
c,f
k,l,n
P
o - all
Chagal Ankaka
238
3
C;b,a,f
-
k,l,n
P
Kotuna Gobola
146
3
c,b,a,f
-
k,l,n
P
P - cool zone
Deyo Genda
300
3
a,b,c
-
k,l,n
Q
Q - temperate zone
Arere
229
3
a,b,c
-
k,l ,n
p
R - hot zone
Bego Kara
232
3
a, b, c
C,f
k,l,n
p
Shebel Beteri
275
3
a,b,c,f
c,f
k,l,n
p
Kolegna Eyesus
170
3
a,b,c,f
k,n,m
R
Selmi Zuria
550
3
a,b,c,f
c,f
o
Q,R
TOTAL
6 977D-12
Specific information on the size and population of districts to the east of Debre Libanos and Wuchale was not available. This information should be collated for future studies. For this prefeasibility study, it is sufficient to note that, as indicated by the topographic maps of the area and from the reconnaissance visit, the occurrence of settlements in this eastern area is
limited.
The reason for the lower population east of the Debre LiDanos District is probably a combination of restricted access (i.e., further distance from main roads) and poorer soil types. Although not confirmed, it appears that soils to the east tend to be more reddish in color, indicating the occurrence of chromic cambisols or eutric nitosols. According to FAO, these soils tend to support open grassland with peasant livestock grazing but not intense cultivation as occurs on the vertic cambisols and pellic vertisols in the western Agat reservoir area. Additionally, because of more rapid drainage of the soil in the eastern area, the cropping season may be shorter with lesser ability to endure drought periods.
(c)      Towns and
Large Villages
A number of towns or large villages are located within the area of influence of the project. These include Fiche, Debre Libanos, DeDre Tsige and Muke Turi.
Debre Libanos will require particular consideration being a historic religious center and the town closest to the proposed powerhouse access road and penstock.D-13
(d)       Religion
The predominant religion in the project area is
Ethiopian Orthodox. About 2 km from the start of the
access road to the powerhouse is a nationally famous
church in Debre Libanos. This church contains the tomb 
of the first Ethiopian saint, Abuneteklehaimanot, and 
the church is named after him.
Besides the famous church in Debre Libanos, there are
several other Ethiopian Orthodox churches throughout the
project area. There is also one Muslem settlement con
taining a mosque, located near Muke Turi just off the
road to Aleltu. The village is called Boku Tigre
suggesting the Tigray origin of the settlers.
(e)       Language
Generally,         about         three         different         languages         are         spoken         in the project area,
-    on the plateau—Oromo
-    in the gorge—Amharic
-    in towns—Oromo and Amharic mixed, and Tigrigna at the Muslem settlement near Muke Turi.
( f) Education
Schooling in the project is comparable to other rural regions in Etniopia. School locations and general information on size of schools, number of teachers and students in the project area, are presented in 
Table D.2.D-12
Specific information on the size and population of
I
districts to the east of Debre Libanos and Wuchale was
not available. This information should be collated for
future studies. For this prefeasibi11ty study, it is
sufficient to note that, as indicated by the topographic
maps of the area and from the reconnaissance visit, the
occurrence of settlements in this eastern area is
limited.
The reason for the lower population east of the Debre
Libanos District is probably a combination of restricted access (i.e., further distance from main roads) and 
poorer soil types. Although not confirmed, it appears tnat soils to the east tend to be more reddish in color, indicating the occurrence of chromic cambisols or eutric nitosols. According to FAO, these soils tend to support open grassland with peasant livestock grazing but not intense cultivation as occurs on the vertic cambisols and pellic vertisols in the western Agat reservoir area. Additionally, because of more rapid drainage of the soil in the eastern area, the cropping season may be shorter with lesser ability to endure drought periods.
(c) Towns and
Large Villages
A number of towns or large villages are located within the area of influence of the project. These include Fiche, Debre Libanos, Debre Tsige and Muke Turi.
Debre Libanos will require particular consideration being a historic religious center and the town closest to the proposed powerhouse access road and penstock.
-D-13
(d) Religion
The predominant religion in the project area is
Ethiopian Orthodox. About 2 km from the start of the
access road to the powerhouse is a nationally famous
church in Debre Libanos. This church contains the tomb 
of the first Ethiopian saint, Abuneteklehaimanot, and 
the church is named after him.
Besides the famous church in Debre Libanos, there are
several other Ethiopian Orthodox churches throughout the
project area. There is also one Muslem settlement con
taining a mosque, located near Muke Turi just off the
road to Aleltu. The village is called Boku Tigre
suggesting the Tigray origin of the settlers.
e) Language
Generally,         about         three         different         languages         are         spoken         in the project area,
-   on the plateau—Oromo
-    in the gorge—Amharic
-    in towns—Oromo and Amharic mixed, and Tigrigna at the Muslem settlement near Muke Turi.
f) Education
Schooling in the project is comparable to other rural regions in Etniopia. School locations and general information on size of schools, number of teachers and students in the project area, are presented in 
Table D.2.D-14
TABLE D.2
SCHOOL LOCATIONS*
Location
No. of
Area
District
Region
Schools
No. of
Students
No. of
Teachers
1
Ensaro
Selale
8
1 448
30
2
Debre
Libanos
Selale
11
1 665
38
3
Wuchale
Selale
9
1 758
39
4
Girar
Jarso
Selale
11
7 031
195
5
Sululta
Menagesha
14
3 746
83
6
Gida
Menagesha
4
965
14
7
Aleltu
Menagesha
5
1 530
31
8
Kimbibit
Tegulet
and Bulga
9
Bosena
Tegulet
and Bulga
21
9 965
277
10
Moja and Wadera
Tegulet
and Bulga
9
1 995
36
11
Moret and
Jiru
Tegulet
10
2 509
47
and Bulga
*For district location, see Plate D-l.D-15
(g) Health Care Services
The Aleltu project covers part of the twelve districts
in three provinces of the Shoa administrative region.
There is at least one health station in every district
of the project area, as shown in Table D.3. Healtn 
station locations are shown on Plate D-l.
Table D.4 gives a general idea of the type of diseases
in the administrative region in which the Aleltu project
is found.
(h) Wildlife and Fisheries
Wildlife
As a result of the extensive agricultural utilization 
of the area, most wildlife habitat has Deen disturbed, the exception to this being the Zega Wedem Gorge. Along the edge of the gorge, there are populations of the Gelada baboon, one of tne four endemic species to Ethiopia. The Gelada baboon, althougn concentrated in the High Semyen, has been noted at Debre Libanos (and Debre Lina areas with small populations in the Mulu and Bole Valley gorges). it is the only surviving representative of tne once widespread group of pri mates of the genus Thenopitnecus. Tne Gelada baboons have a linear distribution along tne escarpment never moving far from the rim. They are mainly vegetarian and very tame. Their only enemy is man wno sometimes snoots them for sport or to acquire the great mane of
tne adult male that is used for traditional head dresses by highland warriors.*
♦"Endemic Mamma1s of
Tourism Commission,
?noiopla
1 7 o 2 •'" Polished by tne EthiopianD-14
TABLE D.2
SCHOOL LOCATIONS*
Location
No. of
Area
District
Reg ion
Schools
No. of
Students
No. of
Teachers
1
Ensaro
Selale
8
1 448
30
2
DeDre
Libanos
Selale
11
1 665
38
3
Wuchale
Selale
9
1 758
39
4
Girar
Jarso
Selale
11
7 031
195
5
Sululta
Menagesha
14
3   746
83
6
Gida
Menagesha
4
965
14
7
Aleltu
Menagesha
5
1   530
31
8
Kimbibit
Tegulet
and Bulga
9
Bosena
Tegulet
21
9   965
277
and Bulga
10
Moja     and 
Tegulet
9
1   995
36
Wadera
and Bulga
11
Moret      and 
Tegulet
10
2   509
47
Jiru
and Bulga
*For district location, see Plate D-l.D-15
(g ) Health Care Services
The Aleltu project covers part of the twelve districts
in three provinces of the Shoa administrative region.
There is at least one health station in every district
of the project area, as shown in Table D.3. Health 
station locations are shown on Plate D-l.
Table D.4 gives a general idea of the type of diseases
in the administrative region in which tne Aleltu project
is found.
(h) Wildlife and Fisheries
Wildlife
As a result of the extensive agricultural utilization 
of the area, most wildlife habitat has been disturbed, the exception to this being the Zega Wedem Gorge. Along the edge of the gorge, there are populations of the Gelada baboon, one of the four endemic species to Ethiopia. The Gelada baboon, although concentrated in the High Semyen, has been noted at Debre Libanos (and Debre Lina areas with small populations in the Mulu and Bole Valley gorges). it is the only surviving representative of the once widespread group of pri mates of the genus Thenop1tnecus. The Gelada baboons have a linear distribution along the escarpment never moving far from tne rim. They are mainly vegetarian and very tame. Their only enemy is man who sometimes shoots them for sport or to acquire the great mane of
the adult male that is used for traditional head dresses by highland warriors.*
•"Endemic MammaIs of
Tourism Commission,
Etniopla, 1982.
published by tne EthiopianD-14
TABLE D.2
SCHOOL LOCATIONS*
Location
Area
District
Reg ion
No. o£
Schools
No. of
Students
No. of
Teachers
1
Ensaro
Selale
8
1 448
30
2
Debre Libanos
Selale
11
1 665
38
3
Wuchale
Selale
9
1 758
39
4
Girar
Jarso
Selale
11
7 031
195
5
Sululta
Menagesna
14
3 746
83
6
Gida
Menagesha
4
965
14
7
Aleltu
Menagesha
5
1 530
31
8
Kimbibit
Tegulet
and Bulga
9
Bosena
Tegulet
21
9 965
277
and Bulga
10
Moja and Wadera
Tegulet
9
1 995
36
and Bulga
11
Moret
and 
Tegulet
10
2 509
47
Jiru
and Bulga
*For district location, see Plate D-lD-15
(g) Health Care Services
The Aleltu project covers part of the twelve districts
in three provinces of the Shoa administrative region.
There is at least one health station in every district
of tne project area, as shown in Table D.3. Healtn 
station locations are shown on Plate D-l.
Table D.4 gives a general idea of the type of diseases
in the administrative region in whicn the Aleltu project
is found.
(h) Wildlife and Fisheries
Wildlife
As a result of the extensive agricultural utilization 
of the area, most wildlife habitat has been disturbed, 
the exception to this being the Zega Wedem Gorge. Along the edge of the gorge, there are populations of
the Gelada baboon, one of the four endemic species to Ethiopia. The Gelada baboon, altnough concentrated in the High Semyen, has Deen noted at Debre Libanos (and Debre Lina areas with small populations in the Mulu and Bole Valley gorges). it is the only surviving representative of tne once widespread group of pri mates of the genus Thenopithecus. The Gelada baboons have a linear distribution along the escarpment never moving far from tne rim. They are mainly vegetarian ana very tame. Their only enemy is man who sometimes shoots them for sport or to acquire the great mane of
the adult male that is used for traditional head dresses by highland warriors.*
*"Endemic Mamma Is of Ethiopia, Tourism Commission, 1982.
published by the EthiopianD-14
TABLE D.2
SCHOOL LOCATIONS*
Location
Area
District
Reg ion
No. of
Schools
No. of
Students
No. of
Teachers
1
Ensaro
Selale
8
1 448
30
2
Debre Libanos
Selale
11
1 665
38
3
Wuchale
Selale
9
1 758
39
4
Girar
Jarso
Selale
11
7 031
195
5
Sululta
Menagesna
14
3 746
83
6
Gida
Menagesha
4
965
14
7
Aleltu
Menagesha
5
1 530
31
8
Kimoibit
Tegulet
and Bulga
9
Bosena
Tegulet
and Bulga
21
9 965
277
10
Moja and Wadera
Tegulet
and Bulga
9
1 995
36
11
Moret
and 
Tegulet
10
2 509
47
Jiru
and Bulga
*For district location, see Plate D-lD—15
(g ) Healtn Care Services
The Aleltu project covers part of the twelve districts
in three provinces of the Shoa administrative region.
There is at least one health station in every district
of the project area, as shown in Table D.3. Health 
station locations are shown on Plate D-l.
Table D.4 gives a general idea of the type of diseases
in the administrative region in which the Aleltu project
is found.
(h) Wildlife and Fisheries
Wildlife
As a result of the extensive agricultural utilization 
of the area, most wildlife habitat has been disturbed, the exception to this being the Zega Wedem Gorge. Along the edge of the gorge, there are populations of the Gelada baboon, one of the four endemic species to Ethiopia. The Gelada baboon, although concentrated in the High Semyen, has been noted at Debre Libanos (and Debre Lina areas with small populations in the Hulu and Sole Valley gorges). it is the only surviving representative of tne once widespread group of pri mates of the genus Thenop1tnecus. The Gelada baboons have a linear distriDution along the escarpment never moving far from tne rim. They are mainly vegetarian and very tame. Their only enemy is man who sometimes shoots them for sport or to acquire the great mane of
the adult male tnat is used for traditional head dresses by nighland warriors.*
’"Endemic Mammals of Ethiopia," puolisned by tne Ethiooian Tourism Commission, 1982.D-16
TABLE D.3
HEALTH CARE SERVICES*
Name
of Health
Area
Station
(Town)
District
1              Hideno                     Ensaro
2               Lemi
Ensaro
Number
of Health Personnel**
Region Stations HA JHA CM
Selale 1 1 1 1 Selale 1 1 1 1
3              Debre Tsige             Debre
Libanos
Selale                   1
-11
4
Muke Turi
Wuchale
Selale
1
1
-
1
5
Silimi
Girar
Jarso
Selale
1
1
-
1
6
Aleltu
Aleltu
Menagesha
1
-
2
1
7
Gelayi
Gida
Menagesha
1
-
1
1
8
Gida
Gida
Menagesha
1
-
1
1
9
Senomulu
Sululta
Menagesha
1
-
1
-
10
Sheno
Kimbibit
Tegulet
1
1
2
1
11            Deneba                        Kimbibit
and Bulga
Tegulet
and Bulga
1
12              Gudo Beret            Moja   and          Tegulet
2--
2 1
Wadera
and Bulga
13
Seledingay
Moja   and
Tegulet
1 1
Wadera
and Bulga
14
Juhur
Moret and
Tegulet
1
1
1
1
Jiru
and Bulga
15
Keteb
Moret and
Tegulet
1
-
1
1
Jiru
and Bulga
16
Chacha
Angolala
Tiro
Tegulet
1
-
1
-
and Bulga
* For district and town locations, see Plate D-1.
••Personnel      descriptions      are      as      follows:      HA      -      Health      Assistance;      JHA Junior Health Assistance; CM - Custodial and Manual.
Note:        In other places in the project area, there are other health stations under construction. There is one hospital in Debre
Berhan.D—17
TABLE D.4
NUMBER AND PERCENTAGE OF LEADING CAUSES FOR HOSPITALIZATION
NO.                 Diagnosis
Number     Percent
1
Normal delivery
1 129
10.2
2
Malaria
836
7.6
3
Complications of pregnancy, childbirth and puerperium
647
5.8
4
Pneumonia (all types)
637
5.8
5
Dysentery (all types)
612
5.5
6
Tuberculosis (all forms)
571
5.2
7
Gastroenteritis and colitis
525
4.7
8
Transport accidents
255
2.3
9
Abortions
239
2.2
10
Malnutrition (all states)
219
2.0
Total Discharge
11 066
100.0
Note:         Ou$            the exPected 132 reports (hospital months),
only 56 were reported (Ministry of Health)
Information          obtained          from          Comprehensive          Health          Servin 
^■T^ r
8
11SBed °y
y and ProgrammingD-18
Fisheries
As a consequence of the ephemeral nature of the streams and lack of fish recruitment from downstream, it is expected that little or no fisheries exist in 
the streams in the impoundment areas.
D3 - SHORT-TERM IMPACTS
DURING CONSTRUCTION
Both detrimental and beneficial impacts will result from the construction of the project. Construction of access roads
and other structures, opening of borrow areas, and heavy construction traffic will disrupt some of the local farmers
and the village of Muke Tun, but should not deleteriously affect Debre Libanos or other towns and villages in the surrounding area. The influx of a migrant labor force will
also impose social pressures on the local communities and public health services. The possibility exists that diseases
not locally endemic can be introduced, with subsequent exposure of local residents. The detrimental impact of these activities can be controlled with appropriate planning and implementation of mitigating measures.
Employment opportunities for area residents, improved access, project purchases of local goods and services, housing rental and purchase by workers of locally produced goods could all be beneficial to the economy of the area and its residents. However, due to the subsistant lifestyle of most of the local residents, it will oe necessary to supply essential services
for any imported work force to ensure that an excess demandD-19
is       not       placed       on       the       local       supply       of       goods       and       services, especially food and medical requirements. With proper plan
ning,         construction         facilities,         such         as         a         hospital         and         school, can be converted into long-term beneficial facilities
subsequent to construction.
D4 - LONG-TERM
IMPACTS OF PROJECT
(a) Effects of Reservoirs
and Project Structures
on Farmers in the Area
As a consequence of the low relief of the area, any reservoir created will be relatively shallow and exten sive. Tinishu Aleltu is the only reservoir which would inundate any of the roads connecting the reservoir areas with Muke Turi. However, Tinishu Aleltu is not consi dered for development, at least in the Stage I construc tion.
With the extensive agriculture in the area, a consider able loss of farmland will occur with creation of tne reservoirs. The areas of the Tiliku Aleltu and Jida reservoirs are 7 and 52 km2 , respectively. This reservoir area presently forms part of a larger farming area whicn extends up to and beyond the houses on tne ridges. The larger farming area is estimated to cover about 150 to 200 km2 around the reservoirs. The farmers in this greater "area of direct influence" will be affected by the creation of the reservoirs with 59D-20
out of the 150 to 200 km2 lost to the reservoirs. 
This will be a 30 to 40% reduction in farming area in this area of direct influence. On a prorated basis, assuming a density of 16 people per square kilometre, this translates into 2,500 to 3,000 people directly or indirectly affected by the reservoirs in the Stage I development. Assuming 5 people per family, this becomes 500 to 600 families.
With the settlement patterns on the plateau (i.e., homes built on the ridge areas), the number of homes actually inundated will be small. However, the farmland around tne homes that would be inundated represents the liveli hood of the local people. As a consequence, it will be necessary co compensate the farmers. Although the land of 500 to 600 families will be affected, not all families will loose 30 to 40% of their land. Some will De only slightly affected such as having the boundaries of tneir farm changed to compensate them. Others will nave a larger extent of their grazing land disappear and will have to be substantially compensated. As they are peasant farmers, compensation in cash is not socially appropriate. Any development plan should include an intensive agriculture improvement plan and/or socially Deneficial rehabilitation and resettlement programs.
Several programs have Deen considered" as discussed Delow.
None of these programs are proposed as definite solutions but are presented to indicate that measures are available to mitigate the impact of the project. Recommended programs should be developed during the feasibility studies and, thereafter, in consultations with the local people, and responsible agencies both government and privateD—21
(i)      As peasant farmers, it is expected that most
would prefer to remain in the same community, even with smaller farm sizes, if they can con
tinue to maintain or improve their standard of living. A redistribution of farmlands, parti
cularly if some farmers elect to resettle else
where, as discussed below, should allow most farmers to continue with the existing farming practices. Farmers can be compensated for dis ruption and reductions in farm size by support programs including supply of (nonmechanized) farm equipment, tools, better housing, training pro grams and improved market access. These farmers grow cash crops and this would be an added benefit to such farmers.
(ii)         Since the soil has been derived from tertiary basalts and tuffs, it may be suitable for
upgraded agriculture.
Some peasant farmers may elect to remain in the same community and change their farming practice from subsistence to cash crop farming, if given appropriate support. This support could extend to supply of (nonmechanized) farm equipment, tools, better housing, training and use of ferti lizers and insecticides.
For example, a simple application of fertilizer on pasture land would increase the production capacity (cattle per hectare) of the land for grazing manyfold. This practice could more tnan compensate for the land inundated by the reservoirs.D-2 2
The agricultural extension service would have to extend over a period of 5 years or more to ensure that the farmers become self-supporting.
(iii)          Some farmers may accept resettlement in areas outside the community. A resettlement program would include transportation of family, belong ings and cattle; new housing; possible construc tion of access roads; and financial support for
one or more years until the new farm can be developed to self-sufficiency.
At the road junction near Sekoro, located between the Jida and Gomoro reservoirs, there is a rela tively new village—Weberi.* The agricultural representative in this village should be con
tacted regarding mitigation planning for the area farmers. It may also be possible to utilize the experience involved in developing this community to assist in any resettlement planning.
(b)       Effects Downstream
from Reservoirs
Downstream from the reservoirs, the natural river flows will De cut off after construction of the dams, except for local streams. Since the rivers are not used for
From discussions with the local people, the town was reformed around 1975 and it is now a village under the farmers association and under the Ensaro District.D-23
human activities, but mainly for watering cattle, the impact will not be severe. Watering holes can be pro vided for cattle along the river downstream from the dams. The watering holes can be supplied by releases from the reservoir or, since reservoir water is
extremely valuable, the watering holes would preferably be supplied by local tubewells providing the groundwater supply is sufficient. The feasiDility studies should address any localized impacts in areas where the rivers presently enter the gorge since there may be effects on inhabitants utilizing the terraces in these areas.
(c)       Effects on Religious
and Historical Monuments
The church at Debre Libanos need not and should not be affected by the development of the reservoirs, pen stocks, tunnels or powerhouse.
In the layout planning, particularly for the powerhouse access road and a penstock route which runs about 2 km west of Debre Libanos, special consideration was given to not disturbing the churches and holy areas. it is believed there would be no problems arising from the finally proposed project structure but this matter
should be diplomatically approached and confirmed in the feasibility study.
(d)       Impact on
Wildlife and Fisheries Wildlife
With          extensive          agricultural          development,          the          area          has precluded any significant wildlife utilization of theD-24
area. The only wildlife species of concern is the
Gelada baboon. The main effect on its habitat will be
in the area where the tunnel/penstock enters the
gorge. This area should be investigated to determine
if any minor relocations are warranted to reduce the impact to any areas used extensively by the Gelada baboons.
Fisheries
Since present fisheries populations are expected to be small or nonexiscant, anticipated impacts are not of concern. With the creation of the reservoirs, a
fisheries development program should be investigated; however, with the drawdown anticipated in most (or all) of the reservoirs, such a program may not be
viable.
(e)       Potential for Aquatic
Macrophyte Development
With the cooler climate in the area and the proposed extensive annual drawdown, the likelinood of developing an aquatic macrophyte problem is lessened. However, since the reservoir would be shallow and result from the inundation of agricultural land, a program to monitor
weed development should be implemented during the early phases of the project with a contingency plan prepared 
to properly deal with any weed problems if they do materialize.
The swamps in tne headwaters of the Tiliku Aleltu and Jida reservoirs should be surveyed for nuisance species that could inoculate the reservoirs.D-25
If open channels are used co connect the reservoirs, 
they should be designed to discourage macrophyte growth. This could include concrete lining, adequate flow, steep sides and/or weed collection/removal facilities. The present canals in the Agat reservoir area should be investigated in this context.
f) Infectious Diseases
Schistosomiasis, often resulting from reservoir development in tropical conditions, appears to be vir tually nonexistant in the project area. This is prob
ably due to the lack of standing water bodies, the
regular occurrence of droughts, cooler climate and a dispersed population. With the creation of the reser
voir and the need for resettlement, it is possible that Schistosomiasis could become a problem if not monitored and controlled. The occurrence of snails of the genuses Bulinus, Biompharlaria and Oncomelania, the intermediate host for Schistosomiasis, should be monitored with a contingency plan developed as shown in Table D.4.
Malaria does occur in the area. For protection of both the indigenous population and the construction work force, a malaria control program should be established prior to start of construction.D-24
area. The only wildlife species of concern is the
Gelada baboon. The main effect on its habitat will be
in the area where the tunnel/penstock enters the
gorge. This area should be investigated to determine
if any minor relocations are warranted to reduce the impact to any areas used extensively by the Gelada baboons.
Fisheries
Since present fisheries populations are expected to be small or nonexistant, anticipated impacts are not of concern. With the creation of the reservoirs, a
fisheries development program should be investigated; however, with the drawdown anticipated in most (or all) of the reservoirs, such a program may not be
viable.
(e) Potential for Aquatic
Macrophyte Development
With the cooler climate in the area and the proposed extensive annual drawdown, the likelihood of developing an aquatic macrophyte problem is lessened. However, since the reservoir would be shallow and result from the inundation of agricultural land, a program to monitor
weed development snould be implemented during the early phases of the project with a contingency plan prepared 
to properly deal with any weed problems if they do materialize.
The swamps in the headwaters of the Tiliku Aleltu and Jida reservoirs should oe surveyed for nuisance species that could inoculate the reservoirs.D-25
If open channels are used to connect the reservoirs, 
they should be designed to discourage macrophyte growth. This could include concrete lining, adequate flow, steep sides and/or weed collection/removal facilities. The present canals in the Agat reservoir area should be investigated in this context.
f) Infectious Diseases
Schistosomiasis, often resulting from reservoir development in tropical conditions, appears to be vir tually nonexistant in the project area. This is prob
ably due to the lack of standing water bodies, the
regular occurrence of droughts, cooler climate and a dispersed population. With the creation of the reser
voir and the need for resettlement, it is possible that Schistosomiasis could become a problem if not monitored and controlled. The occurrence of snails of the genuses Bulinus, Biompharlaria and Oncomelania, the intermediate host for Schistosomiasis, should be monitored with a contingency plan developed as shown in Table D.4.
Malaria does occur in the area. For protection of both the indigenous population and the construction work force, a malaria control program should be established prior to start of construction.D-26
D5 - COST OF
MITIGATING MEASURES
As a result of construction of the Aleltu project, various mitigating measures will have to be implemented, as discussed above. The cost of these measures is charged to the
project.
(a) Rehabilitation/
Resettlement Program
The major social cost will be for renabilitation and/or resettlement associated with the loss of agricultural land. Allowing for implementation of a combination of the rehabilitation and/or resettlement programs discussed in Section D4, the cost is estimated at, on average, $9,000 per family in the area of influence.
This cost for 500 to 600 families totals about
$5 million.
(b) Other Social and
Environmental Programs
Other costs to mitigate the impact of the project will arise with respect to downstream compensation health control programs, modest wildlife and fisheries pro grams, and other social improvements in the area. An estimate of these total requirements and cost is beyond the scope of this prefeasibility study. To allow for
these measures, a provisional sum of $3 million has been provided in the cost estimate for Stage I.D-27
The total socioenvironmental cost, which is carried forward to the cost estimate in Appendix E, is as follows.
Rehabilitation/Resettlement Program $5,000,000 Other Socioenvironmental Programs
TOTAL
3,000,000 $8,000,00059*
yr sc
»— • 0-00’
.^INEWARE
YIDENO
I
4- 9-45
tqpfe r e
Xg, r
\
TSIG0
ANOSW L J®j|
< Jr1                Wj* <■*     1
MUKE
"UR I
/
/
/
9" 3C /
I
I
I
I
I
SENOMULU
JCHANCHQ
GELAY I
\
I
I'
ORAINAGE
BASIN LIMITS
SENDAFA
ADDIS
PLAN
9*00
10
LEGEND
— PROVINCIAL BOUNDARY
_________DISTRICT BOUNDARY
® HEALTH CARE SERVICES
NOTE
NOT ALL
VILuAGES WITH
HEALTH stations are SHOWN ON THE MAP
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY
Plate D-*
ENVIRONMENTAL DEFINITIONS MiIlS
ALELTU HYDROELECTRIC PROJECT lilflYIDENO
U<
1
>MUKE                 jF j . < v / : A. - 1 ’
t TUT r
k X
1 ’V' <z'-
OA
i /I
H
( SENOMULU
:hancho
GELAYI
SHENO
DRAINAGE 8ASIN LIMITS
SENDAFA
ADDIS
SiBfa z
PLAN
9-00
* uOMFHtfS
LEGEND
— PROVINCIAL BOUNDARY district BOUNOARY HEALTH care services
note
not al*, villages with HEAltH stations are shown on the map
ETHIOPIAN ELECTRIC LIG--H--T---A-,NLD/wPcOn WauEihROAHUITTYHO--R---IT--Y------------------------------------------- 1 AlELTU HYDROELECTRIC project lUra
PLATE CH
ENVIRONMENTAL DEFINITIONS nilHliAPPENDIX E
COST ESTIMATE
This appendix contains the detailed cost estimate at prefeasibility level of the first stage of the Aleltu 
project.
The code of accounts of the estimate contains the following main items.
00 Infrastructure
01 Reservoir
02 Interconnection Tunnel
03 Dams
04 Spillways
05 Power Tunnel Intake
06 Power Tunnel
07 Surface Penstock
08 Powerhouse
09 Switchyard
10     Socioeconomic Costs
11     Transmission
12     Gafarsa SuDstation
in the estimate, the quantities, unit prices and construct
costs, based on January 1984 price levels
•Lcvexs, are shown. 
» 
°n
Contingencies vary between 15 and 25# and are inclnc „
tne individual cost items. The average contingency Lunts" co 20.7%. Engineering, construction management and owner-, cost were assumed to oe aoout 12% and are included in thE-2
The estimate covers all direct and indirect items for implementation of the first stage of the project within the ICS, and includes for construction power and socioeconomic programs, all transmission and substation costs. Interest
and escalation during construction is not included. The estimate is presented in the following tables.E-3
APPENDIX E
STAGE 1
PREFEASIBILITY COST ESTIMATE
6 x 50Nm Units
PAGE: 1 OF 7
jteh sub
DESCRIPTION
QUANTITY
UNIT
UNIT PRICE
AMOUNT
TOTAL
REMARKS
(4/
(I)
00
INFRASTRUCTURE
J
ACCESS ROADS
.11
TO DAN SITES
4
KM
50,000
200,000
.12
TO POWERHOUSE AND TUNNEL OUTLET
.121
STEEP CLIFF ACCESS
2.5
KM
1,000,000
2,500,000
.122
WINDING SIDE HILL
6
KM
500,000
3,000,000
Ind. S/Yard Access
.123
FLAT
5.5
KM
100,000
550,000
.13
TUNNEL ROAD i SUR6E TANK ACCESS
20
KM
50,000
1,000,000
.14
CONSTRUCTION SITE ROADS
10
KM
30,000
300,OuO
.15
ROAD MAINTENANCE
-
LS
**
500,000
,2
CONSTRUCTION AND CAMP POWER
.21
ELECTRICAL POWER SUPPLY 4 OPERATION
-
LS
-
2,000,000
Ind. standby diesel
▼
.J
OIL STORAGE DEPOTS
-
LS
-
500,000
.4
CONSTRUCTION CAMPS
.41
MAIN CAMP
.411
SITE DEVELOPMENT 4 SERVICES
-
LS
2,000,000
.412
H0USE5
130
EA
40,000
5,200,000
.413
BUNKHOUSES k LOW INCOME HOUSING
-
LS
-
1,500,000
.414
KITCHEN/DINER/COMMISSARY
-
LS
-
2,500,000
.415
RECREATION HALL/CLUBHOUSE
-
LS
-
1,000,000
.41b
FIRST AID/MEDICAL FACILITIES
-
LS
-
2,000,000
.417
SCHOOL/OPERATE
-
Ind. operation
LS
-
1,000.000
.410
OTHER BUILDINGS
-
LS
-
1,000,000
.42
SECONDARY CAMP AT POWERHOUSE
LS
4.000,000
.43
CAMP OPERATIONS
.431
MAINTENANCE
-
LS
-
1,000,000
.432
SECURITY
-
LS
-
1,000,000
.433
FOOD 4 CATERIN6/CAMP MANAGEMENT
1.900,000
ND
8.00
14,400.000
.5
CONTINGENCY
-
LS
-
11,790.000
Approx. 251
SUBTOTAL 00
-—————
58,940,000
01
RESERVOIR
.1
RESERVOIR CLEARING
-
LS
■J
NONE REQUIRED
2                TREATMENT OF CONTACT ZONES ’ILIKU-ALELTU
77                J IDA
-
-
LS
LS
• *
CONTINGENCY
-
450,uOO
-           1.200.000 450,OuO
Approx. 251.
SUBTOTAL 0!E-2
The estimate covers all direct and indirect items for implementation of the first stage of the project within the ICS, and includes for construction power and socioeconomic programs, all transmission and substation costs. Interest
and escalation during construction is not included. The estimate is presented in the following tables.E-3
N SUB
APPENDIX e
STAGE 1
°REFEASIBILITY COST ESTIMATE b x 50H« Units
DESCRIPTION
PAGE: 1 OF 7
QUANTITY        UNIT       UNIT PRICE             AMOUNT
(1)
If)
TOTAL
«)
REMARKS
INFRASTRUCTURE
.1               ACCESS ROADS
.11             TO DAM SITES
.12                  TO POWERHOUSE AND TUNNEL OUTLET
.121                    STEEP CLIFF ACCESS
.122                     KINDINS SIDE HILL
.123                    FLAT
.13                TUNNEL ROAD i SURGE TANK ACCESS
.14                CONSTRUCTION SITE ROADS
.15                ROAD MAINTENANCE
.2                CONSTRUCTION AND CAMP POKER
.21                ELECTRICAL POKER SUPPLY i OPERATION
.3                OIL ST0RA6E DEPOTS
.4               CONSTRUCT ION CAMPS
.41 MAIN CAMP
.411              SITE DEVELOPMENT A SERVICES
.412              HOUSES
.413              BUNKHOUSES 4 lON INCOME HOUSING
.414          KITCHEN/DINER/CONMISSARY
.415          RECREATION HALL/CLUBHOUSE
,41o               FIRST AID/MEDICAL FACILITIES
.41?              SCHOOL/OPERATE
.418               OTHER BUILDINGS
.42               SECONDARY CAMP AT POWERHOUSE
.43                CAMP OPERATIONS
.431               MAINTENANCE
.432               SECURITY
.433               FOOD I CATERIN8/CAMP MANAGEMENT
.5 CONTINGENCY
SUBTOTAL 00
4     KN                      50,000                200,000
2.5       KN                 1,000,000           2,500,000
6       KN                    500,000           3,000,000
5.5       KN                    100,000                 550,000
20       KN                      50,000           1,000,000
10       KN                      30,000                 300,000
Inci. S/*ard Access
-       LS
-                 500,000
-       LS
-       LS
- 2,000,000
- 500,000
Ind. standbv diesel
-        LS
- 2,000.000
130
EA
40,000              5,200,000
-
LS
-              1,500,000
-
LS
-              2,500,000
-
LS
-              1 000 000
-
LS
,,
- 2 000 000
-
LS
,,
1 000 000
Ind. operation
-
LS
,,
- 1 000 000
-
LS
,,
4,000,000
-
LS
-              1 000 000
-
LS
,,
- 1 000 000
1,800,000
MD
8.00
,,
14,400,1)00
-            11,790,000
Approx. 25Z
----------
59,’40,000
RESERVOIR
.1 RESERVOIR CLEARING
LS
-
.2
TREATMENT OF CONTACT ZONES
•W RESUIRED
,2i
TILIKU-ALELTU
.22
JIDA
lS
-
LS
450,000
1,200,000
CONTINGENCY
450,000
SUBT0T4L 01
------------
100,00^
H PPrcx. 2S/.E-4
SUB
APPENDIX E
STAGE I
PREFEASIBILITY COST ESTIMATE o x 50Mn Units
DESCRIPTION
QUANTITY        UNIT      UNIT PRICE                AMOUNT             TOTAL
REMARKS
<$)
(11 ($)
INTERCONNECTION TUNNEL (Ind. Low Level              Outlet)
.1
MAIN TUNNEL
.11
PORTALS
.111
OPEN CUT ROCK EXCAVATION
120,000
M3
15.00
1,300,000
.112
SURFACE TREATMENT
-
LS
-
100,000
.113
REINFORCED CONCRETE
1,500
M3
350.00
525.000
bi dia.
.12
T UNNEL
.121
ROCK EXCAVATION
57,000
M3
70.00
3,990,000
.122
ROCKBOLTING t STEEL SUPPORT
-
LS
-
200,000
.13
GUIDES,STOPLOGSIHOISTS
-
LS
-
880,000
.14
REMOVAL OF ROCK PLUG
-
LS
-
30,000
’.2                  LON lEVEL OUTLET TUNNEL
.21
TUNNEL AND SATE CHAMBER
.211
TUNNEL AND CHAMBER EXCAVATION
15,000
M3
75.00
1,125,000
.212
ACCESS SHAFT EXCAVATION
500
M3
200.00
100,000
5a dial.
.213
ROCKBOLTING & STEEL SUPPORT
-
LS
-
100,000
Raise
.214
REINFORCED CONCRETE
150
M3
500.00
75,000
.22
OUTLET PORTAL
.221
OPEN CUT ROCK EXCAVATION
14,000
M3
15.00
210,000
.222
ROCK SURFACE TREATMENT
-
LS
•
20,000
.223
REINFORCED CONCRETE
500
M3
350.00
175,000
.23
GUIDES, GATES, HOISTS, LINER
-
LS
-
1,300,000
.3                 CONTINGENCY
SUBTOTAL 02
-       LS
-           2,120,000
Approx. 20Z
.1
TILIKU-ALELTU DAM
.11
COFFERDAMS i UNNATERING
-
lS
200,uUO
. -i
EXCAVATION I FOUNDATION PREPARATION
.12:
COMMON EXCAVATION
70,000
.122
CORE TRENCH EXCAVATION
15.000
N3
N3
123
FOUNDATION PREPARATION
9,000
N2
3.50
10.00
10.00
Belew core
.124
6R0UTIN6
-
LS
245,000
150,000
90,000
500,000
Grout curtain
.13
DAM FILLS
.131
COMPACTED IMPERVIOUS CORE
175,000
4Ki naui
.132
COMPACTED FILTER
80,000
P 0CeS5B3
r
.133
COMPACTED TRANSITION
215,000
M3
KJ
M3
5.u0
15.00
10.00
Screened
.134
COMPACTED ROCKFILL
.134!
FROM EXCAVATIONS
400,000
N3
5.U0
.1342
QUARRIED
250,000
M3
M3
J
12. UO
2,000,000
3,000,000
.135
RIPRAP
40,OOU
10.00
4U0,000
100,000
F o« excavations
r
.14
INSTRUMENTATION
-
aE-5
APPENDII E
STA6E 1
°REFEASIBILITY COST ESTIMATE
PAGE: 3 OF 7
6 x 50N. Units
ITEM sub
description
QUANTITY unit unit price
MOUNT                TOTAL
REHARK5
if)
If)
(f /
I
I
I
I
I
I
I« H
R
P
.2
.21
.22
• •
.222
.223
.224
.23
.231
.232
.233
.234
.235
.24
.3
JIDA DAM
COFFERDAMS & UNWATERING EXCAVATION & FOUNDATION PREPARATION
COMMON EXCAVATION
CORE TRENCH EXCAVATION FOUNDATION PREPARATION GROUTINS
DAM FILLS
COMPACTED IMPERVIOUS CORE COMPACTED FILTER COMPACTED TRANSITION COMPACTED BASALT ROCKFILL RIPRAP
INSTRUMENTATION CONTINGENCY
SUBTOTAL 03
-        LS
230,000        M3
65,000        M3
44,000        112
-        LS
900,000        H3
400.000        «3
875,000        M3
4,790,000        M3
145,000        M3
LS
-        LS
-        200,000
3.50 805,000
10.00
10.00
-
t>50,000
440,000
1,500,000
Below core
5.00                 4,500,000
15.00
10.00
6,000,000
9,750,000
10.00               47,900,000
10.00
•
1,450,000
200,000
SKi naul Processed
Excav. nearby Frca tunnel excav
-               16,655,000
Approx. 201
99,960,000
SPILLWAYS
.1 TILIKU RESERVOIR SPILLWAY
.11                  EXCAVATION
.111
.112
.12
.13
COMMON
ROCK
CONCRETE
SURFACE TREATMENT
18,000
95,000
M3
M3
150 M3
LS
5.00
15.00
300.00
90,000
1,425.000
45,000
150,000
.2 JIDA RESERVOIR SPILLWAY
.2!                   EXCAVATION
.211
.212
.22
.23
COMMON
ROCK
CONCRETE
SURFACE TREATMENT
26,000
120,000
M3
M3
100        M3
LS
-         IS
5.00
15.00
300.00
130,000
1,800,000
30,000
150,000
.3                    CONTINGENCY
SUBTOTAL 04
- 960,000
'
.
^oprcx 251
<.780,000
POWER TUNNEL INTAKE
EXCAVATION
COMMON
OPEN CUT ROCK
ROCK SURFACE TREATENNT
5.000 N3
50,000 M3
-•
00
- uS
l5 -°0
25,000
750.000
75.000
REINFORCED CONCRETE
M3
350.00
BRIDGE ACCESS It DECK
- IS
420,000
300,^00E-6
I TEH SUB
APPENDIX E
STAGE 1
PREFEASIBILITY COST ESTIMATE o x 50Mw Units
DESCRIPTION
PAGE: 4 OF 7 QUANTITY       UNIT      UNIT PRICE               AMOUNT              TOTAL
REMARKS
111
($)
.4
GUIDES, SATE5 I HOISTS
.41
GUIDES 4 EMBEDMENTS
-
LS
-
350,000
.42
TRASHRACKS
-
LS
-
105.000
.43
BULKHEAD SATE
-
L5
-
25,000
.44
CONTROL GATE
-
LS
-
50,000
.45
HOISTS
-
LS
-
55,000
For control 4 service ga
.5                 CONTINGENCY
SUBTOTAL 05
-       LS
-              535.000
Approx. 251
2,o90,000
06
POWER TUNNEL (INCL.SURGE TANK 4 VALVE CHAMBER?
.1 ACCESS ADITS, NUCKIN6 SHAFTS, AND IWIN TUNNEL
.11
ACCESS ADITS
.111
PORTAL
-
LS
-
300,000
.112
TUNNEL
.1121
EXCAVATION
20,UDO
H3
75.00
1,500,000
One adit ® 5i du.
.1122
ROCK BOLTING 4 STEEL SUPPORT
-
LS
-
100,000
.113
ADIT PLUG 4 HISC.
-
LS
-
1UU.00G
10
• A ±
ACCESS 4 MUCKING SHAFTS
.12!
.1211
ROCK EXCAVATION
SINKING SHAFTS
ROCK SUFPORT
3,000
-
M3
LS
300.00
-
900,000
200,000
Two shafts
.1212
. 122
LOCAL concrete support
750
M3
350.00
262,500
.123
SHAFT EQUIPMENT
-
LS
-
500,000
.124
PLUG SHAFTS
-
LS
-
40,000
.13
MAIN TUNNEL
.131
ROCK EXCAVATION-TUNNELS
165,000
M3
120.00
19.800,000
3.oo Gia.
.132
ROCK EICAVAT1ON-SHAFT
4,000
MJ
200.OG
500,000
.133
ROCKBOLTING 4 STEEL SUPPORT
-
LS
-
900,000
.134
CONCRETE
.1341
LINING OF HORIZONTAL TUNNELS
52,000
H3
250.ou
3,000,000
.1342
LINING OF VERTICAL SHAFT SECTIONS
1,000
M3
350.00
350,000
.1343
CONCRETE BEHIND STEEL LINING
3,000
M3
160.OC
5«o,ooo
.1344
OVERBREAK CONCRETE
33,000
H3
HO. 00
4,-20,000
.14
STEEL LINING
1,500
tonne
3,000
4,500,000
.15
VENTILATION 4 MISCELLANEOUS
-
LS
-
1,000,000
SURGE SHAFT I TANK
.21
POCK EXCAVATION
.211
SINKING PILOT SHAFT
1.900
M3
200.00
380,000
use *or ouckinq 4 access
• •- * V
ENLARGEMENT CQR TANK
n?
..3
30.000
13
50.00
1.500,UOO
ROCK SUPPORT
-
LS
-
340,uOO
Bolting i steel rings
CONCRE’E
23’
.INING OF SHAFT
100
MJ
350.00
35.000
TANK
3,500
MJ
300.00
1,050,000
.24
SUPERSTRUCTURE
-
LS
-
500.000E-7
APPENDIX E
STA6E 1
PREFEASIBILITY    COST    ESTIMATE 6 x 50Nv Units
DESCRIPTION
QUANTITY UNIT UNIT PRICE
AMOUNT
IS)
PA6E: 5 OF 7
TOTAL
IS)
RENARKS
(S)
VALVE CHAMBER
CIVIL WORK
ROCK EICAVATION
3, uOO
M3
50.00
150,UOO
ROCK SUPPORT
-
LS
-
50.000
REINFORCED CONCRETE
500
M3
400.00
200,000
MECHANICAL
VALVE
-
LS
-
980,000
One spherical valve
STEEL LINER
LS
-
100,000
2.4a da. x 30a Ig.
CONTINGENCY
-
LS
-
9,912,500
Approx.201
SUBTOTAL 06
59,510,000
SURFACE PENSTOCK
ROCK EICAVATION
30,000
2,500
5,800
M3
CONCRETE ANCHORS
25.00
40U.00
3,000
750,000
1,000,000
17,400,000
750,OuO
Trench
M3
STEEL PENSTOCK
Incl. saoale support
RAIL SYSTEM
tonne
LS
Ind. aamfoid
2ki lg.
CONTINGENCY
-
lS
-
2,930,JOO
15X
SUBTOTAL 07
22,930,000
POWERHOUSE
EICAVATION
COMMON
ROCK(POWERHOUSE i TAILRACE; SLOPE EICAVATION
SLOPE STABILIZATION
RE1NFCRCE0 CONCRETE
15,000 M3
40,000 M3
<00.000 M3
45,000 M2
5.)0                   75,000
25.00           1,000,000
5,u0          2.000,000
<00 180,000
Na Dlastmg, «aCn. exca
1L500 M3
EMBEDDED METAL3/P!PING
400.00
- LS
4,&00,0Q0 300,000
SUPERSTRUCTURE It ARCHITECTURAL
1,300 M2
<200
1,750,000APPENDIX E
STAGE 1
PREFEASIBILITY COST ESTIMATE 6 x 50Mw Units
DESCRIPTION
PAGE: 4 OF 7
ITEM SUB
QUANTITY
UNIT       UNIT PRICE          AMOUNT If)                       (4)
TOTAL
if)
REMARKS
.4
GUIDES, GATES i HOISTS
.41
GUIDES 4 EMBEDMENTS
■ LS
-
350.000
.42
TRASHRACKS
lS
-
105,000
.43
B'JLKHEAD SATE
L5
-
25,000
.44
CONTROL GATE
LS
-
50,000
.45
HOISTS
LS
-
55,000
For control & service ga
.5                 CONTINGENCY
-       LS
-              535,000
Approx. 253
SUBTOTAL 05
2,690,000
06
POWER TUNNEL (INCL.SURGE TANK 4 VALVE         CHAMBER)
.1
ACCESS ADITS, RUCKING SHAFTS, AND MAIN TUNNEL
.11
ACCESS ADITS
.111
PORTAL
-
LS
-
300,000
.112
TUNNEL
.1121
EXCAVATION
20,000
M3
7S.OO
1,500.000
One adit § 5i flu.
.1122
ROCK BOLTING 1 STEEL SUPPORT
-
LS
-
100,000
.113
ADIT PLUG i MISC.
-
IS
-
100,000
.12
ACCESS 4 MUCKING SHAFTS
.121
ROCK EXCAVATION
.1211
SINKING SHAFTS
3,000
M3
300.00
900,000
t mo shafts
.1212
ROCK SUPPORT
-
LS
-
200,000
. 122
lOCAL CONCRETE SUPPORT
750
M3
350.00
262,5U0
.123
SHAFT EQUIPMENT
-
LS
-
500,000
.124
PLUG SHAFTS
-
LS
-
40.000
.. j
i-
MAIN TUNNEL
.131
ROCK EXCAVATION-TUNNELS
165,000
M3
120.00
19.300,000
3.3ft did.
.132
ROCK EXCAVATION-SHAFT
4.000
M3
200.00
800,00V
.133
POCKBOLTING I STEEL SUPPORT
-
LS
-
900,000
.134
CONCRETE
.1341
LINING OF HORIZONTAL TUNNELS
32,000
MJ
250.00
3,000,000
.1342
LINING OF VERTICAL SHAFT SECTIONS
1,000
M3
350.UO
350,000
.1343
CONCRETE BEHIND STEEL LINING
3,000
M3
ISO.00
540,000
.1344
OVERBREAK CONCRETE
33.000
M3
140.00
4,520,000
.14
S”EEL l!N!N6
1,500
tonne
3,000
4,500,000
15
VENTILATION 4 MISCELLANEOUS
-
LS
-
1,000,000
n                 SURGE SHAFT j TANK
n,
. -A
POCK EXCAVATION
!
SINKING PILOT SHAFT
1,900
M3
200.00
380,000
use *or tucking ? access
•»• ▼
ENLARGEMENT ^OR TANK
30,000
M3
50.00
1,500,000
•>2
ROCK SUPPORT
-
IS
-
340.000
Bolting 4 steel rgs
r
CONCRETE
.INING OF SHAFT
100
M3
350.00
35.000
TANK
3,500
M3
300,90
1,050,000
.2<
SUPERSTRUCTURE
-
LS
-
500,000E-7
APPENDIX E
STAGE 1
PREFEASIBILITY COST ESTIMATE 6 x 5OM* Units
DESCRIPTION
PA6E: 5 OF 7
1 SUB
QUANTITY        UNIT        UNIT PRICE               AMOUNT
TOTAL
if)
REMARKS
(S)
(S)
.3
VALVE CHAMBER
.31
CIVIL WORK
.311
ROCK EXCAVATION
3.000
M3
50.00
150,000
.312
ROCK SUPPORT
-
LS
-
50.000
.313
REINFORCED CONCRETE
500
M3
400.00
200,000
.32
MECHANICAL
.321
VALVE
-
LS
-
880,000
One spherical valve
.322
STEEL LINER
-
LS
-
ioo.ooo
2.4b oia. x 30a lg.
.4                CONTINGENCY
-        LS
-               9,912,500
Approx.2CZ
SUBTOTAL Oo
59,510,000
SURFACE PENSTOCK
.1
ROCK EXCAVATION
30,000
M3
25.00
7 50,OoO
Trench
.2
.3
CONCRETE ANCHORS
2,500
5,800
M3
STEEL PENSTOCK
400.00
3,000
2,000,000
17,400,000
Ind. saadle support
tonne
Ind, tamfalfl
.4
RAIL SYSTEM
-
LS
-
750,000
2K« lg.
c
• u
CONTINGENCY
-
LS
-
2,980,000
15X
SUBTOTAL 07
22,380,000
POWERHOUSE
.1
EXCAVATION
.11
COMMON
15,000
M3
5.00
? 5,000
.12
.13
ROCK(POWERHOUSE i TAILRACE)
SLOPE EXCAVATION
40,000
400,000
M3
M3
25.00
5.00
1, 000,GOO
No alasting.    n. exca
2,000,000
Jac
.2
.3
SLOPE STABILIZATION
REINFORCED CONCRETE
45,U00
11,500
M2
M3
4.00
<00.00
180,000
4,600,juO
.4
EMBEDDED METALS/PIP ING
-
LS
300,000
.5
SUPERSTRUCTURE i ARCHITECTURAL
1,300
M2
1,200
1,750,000E-8
ITEM SUB
APPENDIX E
STAGE I
PREFEASIBIL1TV COST ESTIMATE o x 5CMb Units
DESCRIPTION
PAGE: o OF 7
QUANTITY
UNIT     UNIT PRICE             AMOUNT
TOTAL
iS)
REMARKS
ill
(f/
• 0                 ELECT/MECH EQUIPMENT
.61
MECHANICAL
.611
INLET VALVES
0
EA
315.000
1.990,000
o§la au. soheriul
.el2
3ATES/SUIDES/H0ISTS
. 0 i 21
DISCHARGE PIT GATE
-
LS
-
’,000
1
.0122
DISCHARGE DIT GUIDES
-
lS
-
76,uO0
o sets
.6123
DISCHARGE PIT GATE HOIST
-
lS
-
7.000
I
.613
T URBINES 4 GOVERNORS
0
EA
2,150,000
12,900.000
5utH ei. Delten wneei
.□14
POWERHOUSE CRANE
-
LS
-
535,000
sot
.□15
PQKRHOUSc BECh SERVICES
-
LS
-
1,450,000
.o2
ELECTRICAL
.□21
GENERATORS 4 EXCITERS
0
EA
2,400,000
14,400,000
.622
MAIN TRANSFORMERS
-
LS
-
J.0v0,000
.623
POWERHOUSE AUXILIARY ELECTRICAL
-
LS
•
4,0o0,00U
•t
./
CONTINGENCY
-
LS
-
9.630.000
Aoorox. 203
SUBTOTAL 08
57,800.000
?
SWITCHYARD
.1                CIVIL WORKS 4 FOUNDATIONS ,C                SWITCHYARD EQUIPMENT
.3                CONTINGENCY
SUBTOTAL O’ SOCIOECONOMIC PROGRAMS PROVISIONAL SUM CONTINGENCY
SUBTOTAL 10
- LS
- LS
- LS
800,000
-       7,200.000
1,600,000
Aoprox.2< 9.600.000
- LS
LS
- fe.400.0U0
-          l.oOO.OOv
Aporox. 251 9,000,u00
TRANSMISSION
.1          TRANSMISSION          LINES
.11                POWERHOUSE TO PLATEAU
,12                 PLATEAU TO ADDIS iGAFARSA) CGNTIN5ENC
SUBTOTAL 11
3 KM                  200,000 600,000
S5 f.M
lS
100.000         8,500,000 1.320.000
Apprcx.2Gl
;0,92'j.000C4 U
IT0 SUB
APPENDII E
STAGE I
PREFEASIBILITY COST ESTIMATE 6 x :0Mw Units
DESCRIPTION
E-9
QUANTITY                 UNIT UNIT PRICE                    AMOUNT
PAGE: 7 OF 7 TOTAL
REMARKS
(i)
•$>
SAFARSA SUBSTATION
.1 CIVIL NORKS I FOUNDATION
- LS
800,000
SNITCHGEAR
TRANSFORMERS
- lS
-
7,200.000
- LS
3,000,000
.4 CONTINGENCY
- LS
-
2,200.000
Approx.20'
SUBTOTAL 12
13,200,000
TOTAL CONSTRUCTION COSTS (00 to 12) ENGINEERING 1 CONSTRUCTION MANAGEMENT OWNER S ADMINISTRATION
TOTAL ESTIMATED COST
363,130.000
16,310,000 Approx. LOZ 7,260,000 Approx. 2Z
40o,700,000
♦OTHER COSTS (Not Included)
» I. D. C. EscalationAPPENDIX F
TABLE OF CONTENTS
Page
Fl - GENERAL----------------------------------------------------------------------------------------- F“ 1
F2 - OBJECTIVE AND GENERAL APPROACH
OF THE FEASIBILITY STUDY----------------------------------------------------------  F" 1
F3 - SCOPE OF CONSULTING SERVICES-----------------------------------------------------  F" 3
F3.1 - Update of Reconnaissance Study---------------------------------------------------  F- 3
F3.2 - Feasibility Studies--------------------------------------------------------------------  F- 4
F3.2.1        - Investigation of the Selected Site------------------------------------------  F-         4
F3.2.2        - Layout of the Project---------------------------------------------------------  F-         5
F3.2.3         - Power and Energy------------------------------------------------------------  F—      6
F3.2.4         - Transmission Capability ----------------------------------------------------  F—      7
F3.2.5 - Environmental and Socioeconomic
Studies---------------------------------------------------------------------  F-         7
F3.2.6 -          Construction Planning and Scheduling----------------------------------  F- 9
F3.2.7 -          Capital Cost Estimate ------------------------------------------------------  F- 9
F3.2.8 -          Economic Evaluation of
the Project --------------------------------  F-10
F3.2.9 - Financial Studies -----------------------------------------------------------------  F-13
F3.3 - Reporting------------------------------------------------------------------------------------  F-13APPENDIX F
TABLE OF CONTENTS
Page
Fl - GENERAL------------------------------------------------------------------------------------------ F" 1
F2 - OBJECTIVE AND GENERAL APPROACH
OF THE FEASIBILITY STUDY-----------------------------------------------------------  F- 1
F3 - SCOPE OF CONSULTING SERVICES------------------------------------------------------  F- 3
F3.1 - Update of Reconnaissance Study---------------------------------------------------  F- 3
F3.2 - Feasibility Studies---------------------------------------------------------------------  F- 4
F3.2.1 -           Investigation of the Selected Site-----------------------------------------  F-
4
F3.2.2 -           Layout of the Project-------------------------------------------------------  F-
5
F3.2.3 -           Power and Energy----------------------------------------------------------  F-
6
F3.2.4 -           Transmission Capability --------------------------------------------------  F—
7
F3.2.5 - Environmental and Socioeconomic
Studies---------------------------------------------------------------------  F-
7
F3.2.6        - Construction Planning and Scheduling-------------------------------------  F- 9
F3.2.7 
- Capital Cost Estimate -------------------------------------  F— 
9
F3.2.8            - Economic Evaluation of the Project-------------------------------------
F-10
F3.2.9 
F3.3 -
- Financial Studies ------------------------------------------  F-13 Reporting------------------------------------------  F-13
1
I
1
I
I
I
I
IAPPENDIX F
TERMS OF REFERENCE
Fl - GENERAL
EELPA wishes to carry out a feasibility study of the Aleltu project for the purpose of
-   determining if the Aleltu project should be considered for meeting the increasing load demand in the ICS, and the timing of the project for implementation
-   arranging financing for engineering and construction from international financing institutions.
F2 - OBJECTIVE AND GENERAL
APPROACH OF THE
FEASIBILITY STUDY
The principal objectives are
- to determine the technical and the first stage of development
economical feasibility of of the Aleltu hydro projectF-2
-   to determine tne least-cost generation and transmission sequence of development for tne Aleltu project for meeting the expected load demands in the ICS
-   to perform a financial analysis of the recommended project.
The studies should be separated in two distinct phases. The first phase consists of a comprehensive review and update of the reconnaissance study of the ultimate development. From this first pnase study, the first stage of development for
tne Aleltu project should be confirmed.
The second phase of the study consists of a review of the prefeasibility study of the first stage of development, confirmation of its findings and carrying out of the feasibility study.
The consultant shall review all reference material, including the PPS, OctoDer 1982, and the Aleltu Hydro Project, recon naissance and prefeasibility studies, June 1984, noting and addressing the recommendations in the latter report for future studies.
The studies for the hydroelectric development snail include
-   detailed investigations of topography, geology and hydrology
-   project layout, including preliminary design of the access road to the powerhouse
-   study of the transmission system
-   environmental and socioeconomical studies
-   construction planning, including contract packaging and construction schedule
-   estimated cost of the workF-3
-   development of alternative generation and transmission sequences
-   economic analysis
-   financial studies.
The studies mentioned above will be carried out using method ologies which will permit consideration for the eventual financing of the project by international financing agencies.
The consultant should perform all surveys, analysis and collection of data, and engineering work as may be required to attain the objectives set out and to meet all professional standards. In the conduct of his work, the consultant should cooperate and liaise fully with EELPA.
The
and
and
consultant should  be solely  responsible interpretation  of all data obtained  and recommendations of his report.
for          the          analysis the conclusions
F3 - SCOPE OF CONSULTING SERVICES
The studies will include the activities described below.
F3.1 - Update of
Reconnaissance Study
A large number of development schemes of the Aleltu project were identified in the reconnaissance phase of the 1984 reconnaissance and prefeasibility studies. Although most of these schemes were investigated, an accurate definition ofcue development sequence was not possible due to limited availability of 1:50 000-scale mapping and detailed topographic data.
The sizing of the first stage of the Aleltu project will be influenced by tne future development of the ultimate project. Therefore, the ultimate development must be investigated and sufficiently defined to determine the provisions in the first stage for the ultimate development. The scope of work required will De to
-   review the proposed layouts for all schemes (using new 1:50 000-scale mapping in these areas for which only 
1:250 000-scale mapping was available)
-   carry out full topographic surveys of the proposed reser voirs and dam locations, in order to confirm or adjust volume-elevation curves and firm flow calculations
-   prepare revised cost estimates, if necessary, and determine the optimum development sequence of the ultimate development
-   establish tne effect of this sequence on the proposed first stage of development
F3.2 - Feasibility Studies
F3.2.1 - Investigation of
tne Selected Site
The investigations started in the Aleltu project area during the initial reconnaissance and prefeasibilityF-5
studies       must       De       updated       and       extended       to       provide       all
the        data        necessary        for        the        conceptual        designs        which 
are to be prepared as part of the feasibility study.
-   The design study of the project must be based on 
topographic surveys of high precision. The surveys
shall establish points of reference for the control
of alignment and level during the investigations of
the recommended site, and for subsequent construc
tion activity.
-   The geological and geotechnical investigations will
include field mapping, drill holes, exploration
adits,  geophysical surveys,  test pitting  and  labora tory  tests.  The studies will include an  analysis of seismological data and  estimations on  the magnitudes of earthquakes.
- All the hydrologic and meteorologic data available must be analyzed and evaluated for the determination of significant flow parameters, such as long-term average flow, characteristics of the flow in wet and dry years, seasonal and monthly variations of the flows, evaporation losses from the reservoirs, mag nitude and frequency of floods. Data on the trans port of sediments will be required to permit an evaluation of the sedimentation of tne reservoir.
F3.2.2 - Layout of the Project
Studies of project layout will be carried out to determine the best layout and design of all tne components of the hydroelectric project, tne access roads, transmission lines and substations. All theF-4
t le development sequence was not possible due to limited availability of 1:50 000-scale mapping and detailed topographic data.
The sizing of the first stage of the Aleltu project will be influenced by the future development of the ultimate project. Therefore, the ultimate development must be investigated and sufficiently defined to determine the provisions in the first stage for the ultimate development. The scope of work required will be to
-    review the proposed layouts for all schemes (using new 1:50 000-scale mapping in these areas for which only 
1:250 000-scale mapping was available)
-    carry out full topographic surveys of the proposed reser voirs and dam locations, in order to confirm or adjust volume-elevation curves and firm flow calculations
-    prepare revised cost estimates, if necessary, and determine tne optimum development sequence of the ultimate development
- establish the effect of
stage of development
- define the second stage of the Aleltu
F 3.2 - Feasibility Studies
F3.2.1 - Investigation of
tne Selected Site
this sequence
on the proposed first project.
Tne investigations started in the Aleltu project area
during the initial reconnaissance and prefeasibilityF-5
studies must be updated  and  extended  to  provide all the data necessary  for the conceptual designs which are to be prepared as part of the feasibility study.
-   The design study of the project must be based on topographic surveys of high precision. The surveys shall establish points of reference for the control
of alignment and level during the investigations of the recommended site, and for subsequent construc tion activity.
-   The geological and geotechnical investigations will include field mapping, drill holes, exploration 
adits, geophysical surveys, test pitting and labora tory tests. The studies will include an analysis of seismological data and estimations on the magnitudes of earthquakes.
- All the hydrologic and meteorologic data available must be analyzed and evaluated for the determination of significant flow parameters, such as long-term average flow, characteristics of the flow in wet and dry years, seasonal and monthly variations of the flows, evaporation losses from the reservoirs, mag nitude and frequency of floods. Data on the trans port of sediments will oe required to permit an evaluation of tne sedimentation of the reservoir.
F3.2.2 - Layout of the Project
Studies of project layout will be carried out to determine the best layout and design of all tne components of the hydroelectric project, tne access roads, transmission lines and substations. A11 tneF-6
structures and facilities will be defined with sufficient detail to permit the calculation of
quantities and preparation of the cost estimate for
a feasibility level of study.
The optimum dimensions, capacities and principal characteristics of all major project components (civil works, mechanical and electrical equipment) for power production shall be determined in evaluation of the competing alternatives.
Selection of all individual project components should be determined by economic comparisons. Where necessary, the level of detail of site investigations should be such as to allow proper comparisons of alternative developments.
Location and dimensions of major structures for the recommended project should be firmly establisned. The access road required for construction and operation of the powerhouse should be surveyed and designs snould be prepared to include alignment, grade, surfacing and sections so tnat the route is firmly established.
Transmission and substation requirements at Addis Ababa shall be included in the studies and layouts for the Aleltu project.
F3.2.3 - Power and Energy
Power and energy calculations shall be performed in conjunction with evaluation of alternative sequences for best development of the project within the ICS.F-7
F3.2.4 - Transmission Capability
The consultant shall delineate the transmission development alternatives and conduct load flow, short circuit and stability studies to ensure adequate performance of the recommended network and its components under maximum and minimum system load conditions for the initial and extended power plant capacity.
The studies of the transmission line will determine
-   the selected voltage level and the number of lines, taking into account quantities of energy at present and in the future to be transmitted and the
stability of the system
-    the type and level of compensation if required.
F3.2.5 - Environmental and
Socioeconomic Studies
The potential impact by construction of the project
and creation of the reservoirs will include the
following considerations.
(a) Environment
An environmental study will be carried out to estimate me impact which will occur from the construction and operation of the project, and to determine the necessary means to avoid or to alleviate the environmental problems which are identified. The environmental study will includeF-8
construction and operation of the project, and to determine the necessary means to avoid or to alleviate the environmental problems which are identified. The environmental study will include assessment of the impact of the project on the aquatic and terrestrial ecology of the region.
Biomedical studies will be carried out to estimate the potential of various human disease vectors which could occur from the construction and operation of the project, and to determine
the necessary means to avoid or to alleviate the disease problems which are identified.
(b) Socioeconomic
Socioeconomic studies will be carried out to evaluate the social and socioeconomic impact, particularly on tne local population, from the construction and operation of the project. Execution of tne socioeconomic studies will include
- socioeconomic survey of population which would be affected directly and indirectly by the
Aleltu project
-   assessment of land which would be directly influenced by the project reservoirs
-   assessment of religious areas which are of particular importance and may be affected by the project.F3.2.6 - Construction planning
and Scheduling
The consultant will arrange the work into appropriate contract packages and will prepare engineering and construction schedules showing the activities of EELPA, the engineer and the contractors. The schedule shall include all major structures and activities
required for implementation of the project, including land acquisition, buildup of infrastructure and socioeconomic programs. Engineering and construction supervision should be shown as a separate contract. For each contract package, the consultant shall indi cate the preengineering requirements of EELPA, and the engineering and management planning for initiating the project.
F3.2.7 - Capital Cost Estimate
The estimate of cost will contain tabulations of quantities, unit prices and total cost for all the
principal items.
All direct and indirect costs which may occur in construction and completion of the project will be included. The cost of each major project item should be made up of base costs and physical contingency, and these should be broken down into local currency and foreign exchange. Components in foreign currency will also be defined for products manufactured locally which contain within their costs imported components making up a significant portion.F-10
The estimated cost of the recommended project should 
be broken down into the major procurement and con struction contracts, and also possible financing 
packages. A program of cash flow must be presented 
for all the major components of the project with price escalation and interest during construction shown separately. Cash flows should also be provided for
local currency and foreign exchange separately.
F3.2.8 - Economic Evaluation
of the Project
The economic evaluation will be carried out on the
basis of the performance of the Aleltu project in the
ICS.
(a)       Load Forecast
The forecasted demands of energy and system peak capacity will be provided to the consultant by EELPA. The basic economic evaluation will be performed for the most probable forecast, with sensitivity tests carried out for optimistic and pessimistic cases.
(b)       Development of
Alternative Generation
and Transmission Sequences
The consultant should define alternative sequences, with and without Aleltu, for providing generation and transmission capacity to meet the forecasted demands over the study period for theF-l 1
ICS. Prior to defining the generation and trans mission components of the sequences, the consul tant should review the capability of the existing system, and all the known primary generation resources of the country which appear to De economically attractive for the power production. The consultant should consider and take due note of the expected lives of the existing plant in 
the country.
The studies should define firm capacity and energy production, and secondary energy consider ing the useful storage and the interrelated operation of the reservoirs in the ICS. Each sequence of development shall be comparable both in terms of reliability.
In evaluation of the alternative sequences, the study will determine how the energy produced by the various projects (particularly the Aleltu project) can best be used in the ICS, taking into account the characteristics of the present installation and the future planned installa
tions, and to establish the installed capacity 
and the capacity factor of the plants.
(c) Economic Methodology
The economic analysis of the Aleltu hydroelectric project will De carried out using the net present value method to determine the least-cost program of a number of alternative generation sequences witn and without the Aleltu project.F-10
The estimated cost of the recommended project should 
be broxen down into the major procurement and con struction contracts, and also possible financing 
packages. A program of cash flow must be presented 
for all the major components of the project with price escalation and interest during construction shown separately. Cash flows should also be provided for
local currency and foreign exchange separately.
F3.2.8 - Economic Evaluation
of the Project
The economic evaluation will be carried out on the
basis of the performance of the Aleltu project in the
ICS.
(a) Load Forecast
Tne forecasted demands of energy and system peak capacity will be provided to the consultant by EELPA. The basic economic evaluation will be performed for the most probable forecast, with sensitivity tests carried out for optimistic and pessimistic cases.
(b) Development of
Alternative Generation
and Transmission Sequences
The consultant should define alternative sequences, with and without Aleltu, for providing generation and transmission capacity to meet the forecasted demands over the study period for theF-ll
ICS. Prior to defining the generation and trans mission components of the sequences, the cons
tant should review the capability of the existing system, and all the known primary generation resources of the country which appear to be economically attractive for the power production. The consultant should consider and take due note of the expected lives of the existing plant in 
the country.
The studies should define firm capacity and energy production, and secondary energy consider ing the useful storage and the interrelated operation of the reservoirs in the ICS. Each sequence of development shall be comparable both in terms of reliability.
In evaluation of the alternative sequences, the study will determine how the energy produced by the various projects (particularly the Aleltu project) can best be used in the ICS, taking into account the characteristics of the present installation and the future planned installa
tions, and to establish the installed capacity and the capacity factor of the plants.
c) Economic Methodology
The economic
analysis of the Aleltu hy
project will De carried out
value method to determine the least— of a number of alternative generati
droelectric using 
tne
net
present
cost p
rogram
on 
seque
nces
with and without tne Aleltu
project.F-12
-   The analysis will De based on constant value and estimated prices applicable to a fixed date close to the end of the study.
-   The calculation of costs must include invest ment capital, operating fuel costs, fixed costs of operation and maintenance, and interim replacement and equivalent insurance.
-   The economic analysis of the project must be made using both market (actual) and economic (shadow) prices, and taking into account non- quantifiable aspects. The difference between the analysis based on market prices and that based on economic prices for each category affected will be presented in a table.
-   The sensitivity of the results should be examined with respect to changes in the values of all important parameters, e.g., load forecast, discount rate, capital and operating costs.
-    Differential escalation of any major cost item, such as hydrocarbon fuels, snail be identified and the affect of the differential escalation versus constant prices shall be examined.
-   The net present value, internal rate of return and tne benefit/cost ratio for the recommended sequence of development and competitive alter natives shall be presented in the study 
report.F-13
F3.2.9 - Financial Studies
The financial analyses must take the form of a financial forecast during the assumed economic life of the project. Criteria for the financing of the pro posed project will be assumed in consultation with EELPA, and this, together with estimates of capital costs, and costs of operation and maintenance, will be used to determine the tariff required for the sale of electrical energy to achieve the assumed financial objectives. The financial analysis will be performed on the basis of
-    the project by itself
-   the project as a part of EELPAs overall program for generation and transmission in the country.
The financial assumptions established  provisions of agencies.
used        will        conform        with        the international lending
The financial requirements will be expressed in current money terms, taking into consideration escala tion of present prices. The effects of different
rates of inflation on the financing of the project must be determined.
F3.3 - Reporting
A s a minimum, the consultant is expected to meet formally with EELPA on the following occasions
- after 1 month—to review
the consultant's
cions and to discuss and
agree the detaileo
initial ooserva- work. planF-14
-    after about 3 months—to review the load forecasts, the existing and potential generation plants and the proposed criteria for evaluation of alternatives
-    after about 6 months—to review the consultant's early results and the likely future course of the study, and to discuss the proposed outline of the final report, etc
-    to review study progress and findings immediately before preparation of the draft report commences
- to review the consultant's draft report.
On or before submission of the Draft Final Report, the consultant will be expected to give a formal presentation in Ethiopia to EELPA and others, outlining the study and its results and recommendations.
The consultants shall prepare and submit the following reports to EELPA within the time periods indicated.
Report
Progress Reports Draft Final Report Final Report
Timing
At intervals of 2 months
15 months from starting date Within 30 calendar days of
receipt of comments on the Draft Final Report from EELPA
All reports shall be in English.F-15
Progress Reports
Progress reports shall contain
-   a brief summary fo the work accomplished in the preceding 
2 months
-   an outline of work expected to be completed during the
next progress reporting period
- the consultant's comments or recommendations on any
unforeseen conditions that may affect the progress or
quality of their work.
Final Report
Conclusions and  recommendations shall be on  a firm basis from which  EELPA can  make decisions on  implementation  ot the project in the ICS.
The technical and economical feasibility studies tor the hydroelectric development of the Aleltu project will be complete and presented with sufficient detail to servo to support applications for financing to an international lending agency.
Training of
Counterpart Personnel
The Consultant snail work in collaboration with EELPA in the training of counterpart personnel for the transfer of technology with respect to most aspects of tne study. The Consultant shall provide training Dotn in Etniopia and in the Consultant's home office by working on a daily basis with tne counterpart personnel. Provision snail be made■           Ethiopian Electric Light & Power Authority
Aleltu Hydroelectric Project
Reconnaissance and Prefeasibility Studies
Volume 3 - Appendixes June 1984
■
Acres International Limitedj. cA  ,9 Ethiopian Electric Light & Power Authority
r
// >/o-^
Aleltu Hydroelectric Project
Reconnaissance and Prefeasibility Studies
Volume 3 - Appendixes June 1984
nUllfS Acres International LimitedVOLUME 1
VOLUME 2
- EXECUTIVE SUMMARY
-    MAIN REPORT
VOLUME 3         APPENDIXESACKNOWLEDGMENTS ACRES INTERNATIONAL LIMITED
wishes to express its appreciation to the Canadian International Development Agency and the Ethiopian Electric Light and Power Authority for their support in financing and for the many arrangements made in order to carry out this study. We also appreciated the significant contribution and the opportunity to work close with the staff of the Ethiopian Electric Light and Power Authority during this study. Thanks are also due to agencies of the Government of Ethiopia and others who contributed much of the basic information related to the Aleltu Hydroelectric Project.VOLUME 3 - APPENDIXES
TABLE OF CONTENTS
GLOSSARY OF ABBREVIATIONS
LIST OF TABLES
LIST OF PLATES
APPENDIX A - LAYOUT OPTIMIZATION MODEL
APPENDIX B - HYDROLOGICAL STUDIES
APPENDIX C - GEOLOGY, GEOTECHNICAL INVESTIGATIONS AND SEISMICITY
APPENDIX D - SOCIOECONOMIC AND ENVIRONMENTAL ASSESSMENT APPENDIX E - COST ESTIMATE
APPENDIX F - TERMS OF REFERENCEVOLUME 3 - APPENDIXES GLOSSARY OF ABBREVIATIONS
Acres Acres International Limited
ACSR
aluminum core, steel reinforced
ASTM
American Society for Testing and Materials
B/C
benefit/cost
CIDA
Canadian International Development Agency
d
day
DSL
dead storage level
EELPA
Ethiopian Electric Light and Power Authority
ENEL
1
Ente Nazionale Per L Energia Electrica
ERESA
Eritrea Region Electrical Supply Agency
FAO
Food and Agriculture Organization
FI
flood index
FSCL                full surcharge condition level
FSL
ICS
full supply level
interconnected system
MAF
mean annual flood
Mm3
million cubic metres
MM
modified Mercalli
MSL
mean sea level
PF
plant factor
PI
plasticity index
PMF
probable maximum flood
PPS
Power Planning Study
PTD
power tunnel diameterGlossary of Abbreviations - 2
PVC               polyvinyl chloride
r/min               revolutions per minute SCS                self-contained system
t
tonne
UNDP             United Nations Development Program USBR             United States Bureau of ReclamationVOLUME 3 - APPENDIXES LIST OF TABLES
Number            Title
A.l
Results of initial Layout Model Runs
A. 2
Results of Final Layout Model Runs
B.l
Streamflow Records
B.2
Rainfall Records
B.3
Discharge Record Corelations
B.4
Complete and Extended Streamflow Records
B.5
Rainfall Corelations
B.6
Comparison of Chacha and Muger Streamflow Parameters
B.7
Centroid Distances of Subbasins
in Preliminary Hydrology Study
B.8
Monthly Inflow Sequences
of Subbasins
B.9
Reservoir Evaporation Losses
B. 10
Example Jida Reservoir
Regulation Computer Runs
B. 11
Reservoir-Regulation Relationships for Final Model Runs
B. 12
Results of Flood Hydrology Analysis
B. 13                 Flood Index Factors B. 14                 Computed Peak Flows C.l                     Earthquake Intensities
D. 1
Information on Farmer Associations
D. 2                   School LocationsNumber
D.3
D.4
E.l
Title
Health Care Services
Number       and       Percentage       of       Leading Causes for Hospitalization
Prefeasibility Cost EstimateVOLUME 3 - APPENDIXES LIST OF PLATES
Number           Title
A-l
Schematic of Project Components
A-2                  Computer Model Flow Chart
B-l                   Hydrologic Data Base
B-2                  Hydrometric Recording Station
B-3                  Hydrology Studies-DetaiIs
C-l                   Geology of Tiliku Aleltu Dam Site
C-2                  Geology of Jida Dam Site
C-3                  Geological Section of Zega Wedem Gorge C-4                  Geological Stereonets
C-5                  Seismicity of Ethiopia
C-6                   Potential Jima Impervious Borrow Area C-7                   Properties of Impervious Materials
D-l
Environmental DefinitionsAPPENDIX A
TABLE OF CONTENTS
LIST   OF   TABLES
LIST OF PLATES
Page
Al -       MODEL CONCEPT-------------------------------------------------------------------------------- A-       1
A2 -      MODEL COMPUTATIONAL STEPS -----------------------------------------------  A-      2
A3 -      RESERVOIR OPERATION------------------------------------------------------------  A-      2
A3.1 - Individual Reservoir Live Storage ---------------------------------------------  A-      3
A3.2 - Individual Reservoir Degree of
Regulation----------------------------------------------------------------- A- 4
A3.3 - Multireservoir Operation--------------------------------------------------------- A- 5
A4 - SIZING AND COST FUNCTIONS OF PROJECT
COMPONENTS---------------------------------------------------------------------------  A- 6
A4.1 - Dams--------------------------------------------------------------------------------  A- 8
A4.2 - Interconnection Tunnels ---------------------------------------------------------  A- 9
A4.3 - Power Tunnel---------------------------------------- -----------------------------  A-ll
A4.4 - Penstock------------------------------------------------------------------------------    A-14
A4.5 - Powerhouse---------------------------------------------------------------------------- A-16
A4.6 - Other------------------------------------------------------------------------------------ A-17
A5       - ENERGY AND CAPACITY----------------------------------------------------------  A-18
A6       - CALCULATION PROCEDURE-----------------------------------------------------  A-19
A7       - PROGRAM DESCRIPTION-------------------------------------------------------------- A-21
A7.1 -
RESECO-------------------------------------------------------------------------  A-23
A7.2 -
READ-------------------------------------------------------------------------  A-2 3
A7.3 -
MARGIN------------------------------------------------------------------------  A-24
A7.4 -
DEGREG------------------------------------------------------------------------  A-24
A7.5 -
ITER------------------------------------------------------------------------------  A-24
A7.6 -
ROUTE--------------------------------------------------------------------------- A-25
A7.7 -
OPTRES ---------------------------------------------------------------------  A-2 5
A7.8 -
OUTPUT--------------------------------------------------------------------- a-2 5
A7.9 -        Example Output-----------------------------------------------------------------  A-26
PLATESLIST   OF   TABLES LIST OF PLATES
Al - MODEL CONCEPT -------------------------------------
_____________________________  A- 1
A2       - MODEL COMPUTATIONAL STEPS --------------------------------------------------------- A       2
A3       - RESERVOIR OPERATION------------------------------ ~
A_     2
A3.1 - Individual Reservoir
A3.2 - Individual Reservoir Degree of
Live     Storage ----------------------------- a-  j
Regulation-------------------------------------------------------------------------- A“ A3.3 - Multireservoir Operation-------------------------------------------------------------------  A"  5
A4 - SIZING AND COST FUNCTIONS OF PROJECT
COMPONENTS--------------------------------------------------------------------------------  A“ °
A4.1 - Dams-------------------------------------------------------------------------------------  A“ 8
A4.2 - Interconnection Tunnels --------------------------------------------------------------  A- 9
A4.3 - Power Tunnel--------------------------------------------;-------------------------------  A-11
A4.4 - Penstock---------------------------------------------------------------------------------- A-14
A4.5 - Powerhouse------------------------------------------------------------------------------  A-16
A4.6 - Other-------------------------------------------------------------------------------------- A-17
A5 - ENERGY AND CAPACITY---------------------------------------------------------------------  A-18
A6 - CALCULATION PROCEDURE----------------------------------------------------------------- A-19
A7 - PROGRAM DESCRIPTION---------------------------------------------------------------------  A-21
A7.1 
- RESECO--------------------------------------------------------------------------  A
-2 3
A7.2 
- READ---------------------------------------------------------------------------------
-  X-23
A7.3 
- MARGIN-----------------------------------------------------------------------------
-  A-24
A7.4 
- DEGREG-----------------------------------------------------------------------------
-  A-24
A7.5 
— ITER ———— ——— — — — — — — — — — — — — — 
a—94
A7.6 - ROUTE ---------------------------------------------------------------------------------
A7.7 - OPTRES --------------------------------------------------------------------------------
A7.8 - OUTPUT --------------------------------------------------------------------------------
A7.9 - Example Output-------------------------------------------------------------------------
PLATESAPPENDIX A
LIST OF TABLES
Number             Title
A.l                      Results of Initial Layout Model Runs A.2                     Results of Final Layout Model RunsAPPENDIX A LIST OF PLATES Number           Title
A-l
Schematic of Project Components
A-2                  Computer Model Flow ChartAPPENDIX A
LAYOUT OPTIMIZATION MODEL
Al - MODEL CONCEPT
The proposed Aleltu development concept comprises a complex configuration of reservoirs which are interconnected by pressure tunnels and/or open channels. It is assumed that
the project will be developed as one or more independent multireservoir systems; and that each independent system of reservoirs will be connected by a power tunnel and penstock to a powerhouse. This concept is illustrated on Plate A-l.
To handle the complex analysis associated with the inter active operation of the reservoirs and the numerous system alternatives, a mathematical model was developed.
The most significant variable in energy production within a system is reservoir regulation of the inflows. Therefore, 
the objective of the model is to determine reservoir eleva tion and the corresponding dam neight on the basis of one of two criteria
to determine the least cost of the major project structures for a given degree of regulation
to optimize energy production against cost of the major project structures on the basis of marginal cost of long term grid energy supply.A-2
The model is herein referred to as the Layout Optimization Model and a detailed description is contained in the following sections.
A2 - MODEL COMPUTATIONAL STEPS
The principal computational phases of the model consist of
-    operating rules for the multireservoir system
-    sizing and costing of structural components of the system
-    calculation of economic parameters
-    optimizing the dimensions of structural components of the developments
-    calculation of energy production
-    evaluation of economic performance.
The operating rules for the multireservoir system are based on interreservoir sharing in regulating the natural inflows, sharing in supply of power flows and spilling of inflow in excess of the combined storage capability.
A3 - RESERVOIR OPERATION
The purpose of this section is to deserioe in detail tneA-3
characteristics are input functions to the layout optimization model and are outlined in Sections A3.1 and A3.2, respectively. The reservoir operation is described by the reservoir elevation, the regulated flows between inter connected reservoirs, spill, and by the long-term average power flow. This is presented briefly in Section A3.3.
A3.1 - Individual Reservoir
Live Storage
Based on available topographic maps and some field surveys performed during the study, reservoir storage volumes were calculated for a number of reservoir elevations. Regression analyses were then performed to determine the equation des cribing reservoir storage as a function of elevation. The general form of the equation is based on the standard function
y = a + bxc
and was derived to be
A
LS = Ax          + A (EL-EL )
2r
3
(1)
where LS
= reservoir live storage (Mm3)
EL                       = reservoir FSL (m)
ELr
9 
= reference (dead storage) elevation 9        ^3 “ site-specific coefficients related
storage
(m) to liveA-4
A3.2 - Individual Reservoir
Degree of Regulation
To evaluate potential Aleltu developments  it was necessary 
r
to assume that benefits are derived from firm (primary) energy generation only. Secondary energy is assumed to have negligible economic value.* Firm energy corresponds directly with the firm power flow from the reservoir. By defining the firm power flow of an individual reservoir and subsequently that of the entire multireservoir system, the energy benefit
is implicitly described.
The firm power flow corresponds to the reservoir discharge that can be sustained throughout the periods of dry hydro logy. Degree of regulation is defined as the firm power flow divided by the long-term average flow. (Thus, the degree of regulation can vary from 0.0 to 1.0. For example, a reser voir which fully regulates the inflow has a degree of regula tion equal to a value of 1.0.) By using a mass curve analy sis, the firm power flow was determined for a specific reser voir elevation. A description and example of the mass curve analysis is presented in Appendix B. By repeating tne mass curve analysis for several reservoir elevations, the reser voir degree of regulation was defined as a function of reser voir live storage by the same standard function as for the live storage (Section A3.1 aoove) and resulted in the following equation.
•This assumption is based on the fact that the interconnected system (ICS) is an all-nydro system. However, complementary operation of the existing I<_S reservoirs can permit firming up of about 200 GW-h/yr of secondary energy. This is not considered in the model, as discussed in Section 7 of the
main report.A-5
DOR X Q ma where
+ B (LS)
2
(2)
DOR
= degree of regulation
Qma
= mean annual flow
Qp
LS
= firm power flow
= live storage
B l' B2'
= site-specific coefficients related to power
flow
A3.3 - Multireservoir Operation
The reservoir live storage (Section A3.1) and the reservoir degree of regulation (Section A3.2) describe the hydraulic capabilities of individual river/reservoir complexes. The operation of the multireservoir system is based on the
following specific characteristics of the Aleltu develop
ment .
(a) The reservoirs are interconnected by pressure tunnels or open channels. Excess water in one reservoir is distri buted to other reservoirs, as storage is available, to minimize spill.
(b)       Natural inflows are routed through the reservoirs in one of three ways
- regulated by the reservoir(s) constructed in the
specific river
- discharged through interconnection tunnels or channels to De regulated by other reservoirs in the multireservoir systemA-6
- spilled from the multireservoir system.
The system operation is determined by a water balance of the natural inflows, regulated discharges and spill tnroughout the network. The long-term average power flow is equivalent to the regulated flow which can be supplied by a specific multireservoir system.
A4 - SIZING AND COST FUNCTIONS
OF PROJECT COMPONENTS
The system components (Plate A-l) which have a significant influence on project cost are
-    dams
-    interconnecting tunnels
-    power tunnel
-    penstock
-    powerhouse.
The sizing and costing functions of these components were defined in terms of reservoir operation as follows.
Component Dams
Size and Cost Function Reservoir full supply level (FSL)
Interconnecting
Tunnels
Regulated discharge (long-term average
power flow) and unregulated discharges
(expressed as a linear function of
long-term average power flow)A-7
Component Power Tunnel Penstock Powerhouse
Size and Cost Function
Long-term average power flow
Long-term average power flow
Reservoir mean operating level (defined by the FSL) and long-term average power flow
It can be seen that the cost functions of the individual components contain two variables
-    the reservoir FSL
-    the long-term average power flow.
These variables are interdependent: to each FSL belongs a long-term average power flow equal to or less than the mean annual inflow.
Therefore, for any given FSL, all project costs are defined, and marginal costs can be calculated. The optimum FSL can be determined by calculating the marginal costs and correspond ing marginal benefits for a number of reservoir levels.
The cost functions are discussed in the following sections. It is noted that the costs of additional components such as the surge chamDer, spillways, access, etc, are included as part of the costs of the individual components, as applic able.A-b
A4.1 - Dams
The cost function of the dams in the Aleltu development is related to dam volume. The dam volume is dependent on reser voir elevation and topography of a specific site. Based on a standard layout for earth- and rock-fill dams, volumes for dams were determined for various reservoir elevations. The standard layout was based on dam slopes of 2.5H:1V for dam heights less than 25 m, and 3H:1V for dam heights in excess of 25 m.
Therefore, for each reservoir site, dam volumes were calcu lated in terms of reservoir elevation and were defined by the following equation.
C (EL-EL )
2r
where
DV                       = dam volume (Mm3)
(3)
EL ELr
C 1' C2'
= reservoir FSL (m)
= reference (dead storage) elevation (m) C  = site-specific coefficients
3
Unit costs of dam fill material were assumed to vary with the quantity of fill material and were defined on the basis of
the following equation.
UCD
D2(DV)
(4)A-9
where
DV                     = dam volume (Mm3)
UCD                   = unit cost of dam volume ($ mi 11ion/Mm3) D , D , D  = cost coefficients
23
The resulting dam cost function
DC = UCD x DV
where
DC = dam cost ($ million)
DV = dam volume (Mm3)
UCD = unit cost of dam volume ($ million/Mm3) A4.2 - Interconnection Tunnels
is then defined as follows.
(5)
The principal design feature of the interconnection tunnels is the diameter. The selection of a design diameter is dependent on the regulated and unregulated flows to be discharged through the tunnel. The design criteria for tne tunnel diameter are as follows.
(a) Regulated Discharges
To limit the extent of water level fluctuation within the reservoir system, a maximum head loss over the tunnel length of 1.0 m was arbitrarily selected. The discharge used in the calculation is equivalent to the regulated discharge.A-10
(b) Unregulated Discharges
To permit distribution of unregulated inflows over the reservoirs, particularly during peak runoff, a discharge of six times the regulated discharge at a head loss of 5.0 m was allowed.
The design diameter of the interconnection tunnel was derived through the use of the Darcy-WeisDach equation
HL =
where
(6)
HL = head loss
f = friction factor
L = tunnel length
D = tunnel diameter
v = tunnel flow velocity
g = acceleration of gravity
This resulted in the following equation. ITD = E  X (Q ) ’  x (ITL) *2
04                   0 xp
where
(7)
°p ITL =
= regulated (power) discharge = tunnel length
El =    = constant, comprising friction factor, design, discharge multiplier, etcA-ll
The         interconnection         tunnels         are         assumed         to         be         unlined.         Their cost function is defined as follows (0.5-m overbreak
excavation is allowed for).
2
ITC = E  x [E  + E (ITD) ] ITL
234
where
(8)
ITC
= interconnection 
tunnel
cost ($ million)
ITD
= interconnection 
tunnel
diameter (m)
ITL
= interconnection 
tunnel
length (m)
E2               = unit cost of excavation for interconnection tunnel (is constant) ($/m3)
E , E  = specific coefficients
34
A4.3 - Power Tunnel
To establish the variation of tunnel cost with power flow, the definition of optimum tunnel diameter is required. Opti mization of the power tunnel diameter is carried out on the basis of marginal variation in the cost of construction and value of head loss, such that the marginal cost is equal to the marginal benefit.
The marginal benefit is derived from energy savings due to head loss reduction in the power tunnel with respect to increased tunnel diameter. The marginal benefit is evaluated using the long-term average grid cost of energy.
Costs are based on a concrete-lined tunnel. The marginal annual cost of the power tunnel is derived by differentiating the annual cost function of the power tunnel with respect toA-10
(b) Unregulated Discharges
To permit distribution of unregulated inflows over the
reservoirs, particularly during peak runoff, a discharge
of six times the regulated discharge at a head loss of
5.0 m was allowed.
The       design       diameter       of       the       interconnection       tunnel       was       derived through the use of the Darcy-Weisbach equation
(6)
wnere
HL = head loss
f = friction factor
L = tunnel length
D = tunnel diameter
v = tunnel flow velocity g = acceleration of gravity This resulted in the
following equation.
(7)
where
= regulated (power) discharge
ITL = tunnel length
= constant, comprising friction factor, design, discharge multiplier, etcA-ll
The         interconnection         tunnels         are         assumed         to         be         unlined.         Their cost function is defined as follows (0.5-m overbreak
excavation is allowed for).
2
[E  + e (itd) ] itl
34
(8)
where
ITC
= interconnection 
tunnel
cost ($ million)
ITD
= interconnection 
tunnel
diameter (m)
ITL
= interconnection 
tunnel
length (m)
E 2                       = unit cost of excavation for interconnection tunnel (is constant) (S/m^)
E^, E  = specific coefficients
4
A4.3 - Power Tunnel
To establish the variation of tunnel cost with power flow, the definition of optimum tunnel diameter is required. Opti mization of the power tunnel diameter is carried out on the basis of marginal variation in the cost of construction and value of head loss, such that the marginal cost is equal to the marginal benefit.
The marginal Denefit is derived from energy savings due to head loss reduction in the power tunnel with respect to increased tunnel diameter. The marginal benefit is evaluated using the long-term average grid cost of energy.
Costs are based on a concrete-lined tunnel. The marginal annual cost of the power tunnel is derived by differentiating the annual cost function of the power tunnel with respect toA-12
the diameter. The tunnel cost function contains an excava tion component and a concrete liner component. Costs for access and mucXing are incorporated in the unit cost of excavation. On this basis, the power tunnel cost per unit of length is as follows.
C  + ir(PTD + tp t  C J x PTL
1
}2
x PTD2        x PTL
where
PTC = power tunnel unit cost ($ million/km)
PTD          = power tunnel diameter (m)
(9)
PTL
= power tunnel length (km)
C1
UCPTi
= concrete liner thickness equals PTD/15 (m)
= unit cost of tunnel excavation (constant)
ucpt2
= unit cost of concrete (constant)
?1
= constant
The tunnel cost was amortized over a 50-yr period at a discount rate of 12% to determine equivalent annual costs.
The unit energy benefit as a function of head loss in the
power tunnel is evaluated utilizing tne Darcy-Weisbacn formu lation of head loss (see Section A4.2 above), resulting in 
the following equation.
PTB
x W x PTL
( 10)A-13
where
PTB
= unit power tunnel energy benefit ($ million/kra)
fQ
Qp 
W
= weighted flow factor
= long-term average power flow (m^/s)
= grid cost of energy (mills/kW*h)
PTL
= power tunnel length (km)
f2
= constant
The weighted flow factor (fg) is used to adjust the power flow to represent plant stacking conditions in the ICS load duration curve (i.e., to reflect the peaking role). For this purpose, a weighted mean power flow is calculated as follows.
Q           = weighted mean                power flow
T, t =        duration
Qp         = mean power flow
fq            = flow factor
Various plant operation  modes were used  to  determine probable stacking  configurations and  the corresponding  flow factor was calculated. Ultimately, a factor of 1.30 was adopted.
The economic diameter was calculated by equating the marginal cost and marginal benefit functions, and solving the power tunnel diameter (PTD).A-14
3PTC  3PTB
3PTD ’ 3PTD
(12)
The       optimum       power       tunnel       diameter       for       the       layout       optimization model was found to De
PTD = F3
3/7
(13)
and the power tunnel cost for fg equals 1.30 is
6/7
PTC = F  x (Q ) x PTL
4p
where
PTD          = power tunnel diameter (m)
PTC          = power tunnel cost (S million)
PTL           = power tunnel length (km)
°P              = mean power flow (m /s)
F 4 = constants
A4.4 - Penstock
Penstock diameters are optimized on the same oasis of
installed        cost        and        value        of        head        losass for tfheor  power tunnel.
Because of Che high head, the penstock cost function is
(14)
3
developed by considering the desian of ments. Each segment is defined in terms of
.       . . 
’ tne Penstock in seg rms of ^e length of
,
penstock within a particular elevaH«„            elevation ran9e and, therefore
the penstock diameter is assumed to be cone
segment.  Segments were evaluated  for r eacfl
(
. 
therefore, constant for each
u       . 
 100 m of eleva
tion. The following equations illustrar k
a cost function for each penstock segment " 6 deVel°pment °fThe        thickness        of        steel        plate hydrostatic head.
A-15
in the penstock increases with
( 15)
where
t2 = thickness of steel plate in penstock (m)
H| = hydrostatic head (m) for penstock segment "i"
PD = penstock diameter (m)
F = allowable tensile stress (2,426 kg/cm2)
The unit weight of the penstock is given as follows.
U = yll( PD + t )
2                        1,000
where
U = unit weight                 of penstock (kg/m)
y = density of                 steel (7,850 kg/m3)
The unit cost of penstock construction is given as follows. p   — c°s u
P       1,000 where
(16)
(17)
Cp = unit cost
Cg = unit cost
of    penstock (§ million/km) of     steel construction (52.50/kg)A-16
An     average     cost     coefficient     was     determined     on     the     basis     of all penstock segments.
Similar     to     the     power     tunnel,     the     unit     energy     benefit     due     to energy savings is evaluated from the Darcy-Weisbach formula.
(18)
The marginal cost and benefit is computed by differentiating the appropriate function with respect to the penstock dia meter. By equating the two marginal costs and solving for penstock diameter, the economic diameter is given as follows.
PD = G  x
2
(19)
and the penstock cost is
x (Q )
p
6/7
x PL
(20)
where
PD
= penstock
diameter (m)
PC
= penstocx
cost ($ million)
PL
= penstocx
length (km)
On             = mean power flow (m^/s)
G 2' G3 = conscants 9iven particular lengtn versus depth profile of penstock
A 4.5 - powerhouse
The cost of the powerhouse is equal to the summation of equipment cost and structural powerhouse cost, includingA-17
switchyard, and was expressed as the unit cost of installed capacity. This was estimated at $250/kW. The formulation of installed capacity is as follows.
IC = H
net
where
x Q x H P
(21)
IC       = installed capacity
H        = net head
net
Qp = power flow
= coefficient, incorporating plant factor (see Section A5) efficiency, etc
Since the net operating head can be calculated from the hydraulic losses in the conveyance system (see Section A5), the powerhouse cost function becomes as follows.
PHC   =   [H_ 
2 
x   Q
p
]
x W + H3
( 22)
where
PHC = powerhouse cost ($ million)
Qp = long-term average power flow
H2         =         coefficient         related         to         capacity         function         (Hnet
and )
H3 = lump sum costs from separate project components (see
Section A4.6)
W = unit cost of installed capacity
A4.6 - Other
Lump       sum       costs       were       calculated       for       separate       components       of       tne project, such as access, surge chamber and transmission.
These       costs       were       introduced       in       the       model       as       independent       costs and were accommodated under powerhouse cost.A-16
An      average      cost      coefficient      was      determined      on      the      basis      of all penstock segments.
Similar       to       the       power      tunnel,      the energy savings is evaluated from
unit      energy      benefit      due      to the Darcy-Weisbach formula.
PEB = GJ
3
x W
(18)
The marginal cost and benefit is computed by differentiating the appropriate function with respect to the penstock dia meter. By equating the two marginal costs and solving for penstock diameter, the economic diameter is given as follows.
(19)
and the penstock cost is 6/7
X (Q )
p
x PL
( 20)
where
PD             = penstock diameter (m) PC             = penstock cost ($ million) PL             = penstock length (km)
Qp
G , g  =
23
= mean power flow (m-^/s)
= constants given particular length versus depth profile of penstock
4.5 - powerhouse
The cost of tne powerhouse is equal to the summation of equipment cost and structural powernouse cost includingA-17
switchyard, and was expressed as the unit cost of installed capacity. This was estimated at $250/kW. The formulation of installed capacity is as follows.
(21)
where
IC      =  installed capacity H       =  net head
net
Qp  = power flow Hjl = coefficient, 
incorporating plant factor (see
Section A5) efficiency, etc
Since the net operating head can be calculated from the hydraulic losses in the conveyance system (see Section A5) , the powerhouse cost function becomes as follows.
PHC = (H x QI 2 P
X W + h3                                                                                                                                   (22)
where
PHC = powerhouse cost ($ million)
Qp = long-term average power flow
H2 = coefficient related to capacity function (Hnet
and Hp
H3 = lump sum costs from separate project components (see
Section A4.6)
W = unit cost of installed capacity
A4.6 - Other
Lump       sum       costs       were       calculated       for       separate       components       of       tne project, sucn as access, surge chamber and transmission.
These       costs       were       introduced       in       the       model       as       independent       costs and were accommodated under powerhouse cost.A-18
A5 - ENERGY AND CAPACITY
The       generation       capability       of       the       project       is       derived       from       the general relationships as follows.
Capacity (CAP) = 9.812 n x Qpk x Hngt
Energy (E) where
p          net x time = 9.812 n x Q  x H
(23)
(24)
n = overall turbine/generator efficiency (0.85)
Qpk = Peak flow equals Ql/PF
Qp = regulated (power) flow
Hnet = net head (m)
From consideration of the ICS characteristics in the 1990s, a plant factor (PF) of about 0.4 was adopted (see Section 7 of the main report).
The net head is the difference between average operating reservoir level and the centerline of the power nozzles on the turbines (ELEV?) in the powernouse, less losses, i.e., as follows.
H = DSL + 0.75 (FSL - DSL) - ELEV - H - H
net
where
DSL = dead storage level (m) FSL = full supply level (m)
r
i LT LP
(25)
Hlt  = head loss in power tunnel (m)
h LP = head loss in PenscocK
The term "0.75 (FSL - DSL)" provides a weighted average operating level of the reservoir.A-19
A6 - CALCULATION PROCEDURE
With  the formulas presented  in  Sections A3  to  A5,  the average and  incremental cost of energy  can  be calculated  for selected reservoir FSL. Optimum component sizing is carried out
simultaneously.
For a given  FSL,  the marginal cost of the project corresponds to  the sum of the incremental costs of the individual project components and is determined in the following manner.
From        the        individual        reservoir        live        storage,        the        change        in power flow amounts to
3Q _ 3Q BLS
3EL BLS X 3EL
The incremental costs are as follows. Dam
3 DC  3 DC 3DV BEL " 8DV X 3EL Interconnection Tunnel
(26)
( 27)
3ITC
BEL          3ITD X Power Tunnel
3ITC          3ITP 3Q 3LS
in
8Q BLS 3 EL
A
n r o x
( 28)
3PTC 3EL
3PTC
9Q     x
3Q8LS_ B 3ELLS
r              A » r-< V
( 29)A-20
Penstock
3PC  3PC 3Q 3LS
3EL 3Q X 3LS X 3ELC Powerhouse
( 30)
3PHC
=
3PHC      3Q      3LS
3EL              3Q X 3LS X 3EL The incremental project cost 3Project Cost  3DC 3ITC
(31)
3EL
3EL + 3EL
is then
3PTC 3PC 3PHC 3EL * 3EL * 3EL
( 32)
where
Q        = power flow (m^/s)
EL     = FSL (m)
LS      = live storage (Mm3)
DC     = dam cost ($ million)
DV =  = dam volume (Mm3)
ITC = = interconnection tunnel cost (S million)
ITD = = interconnection tunnel diameter (m)
PTC = = power tunnel cost ($ million)
PC =   = penstock cost ($ million)
PHC = = powerhouse cost ($ million)
The     margina     1     unit     costs     of     available     firm     energy     can     now     be calculated.
MUC      A x
3Project Cost  3E
3EL                ’ 3EL
f
( 33)A-21
where
MUC = marginal unit cost (mills/kW«h)
A       =       amortization       factor       at       12%       over       50       years
E = available firm energy (GW-h/yr)
and        this        is        compared        to        the        long-term        incremental        supply        cost of 35 mills/kW«h.
The        average        unit        cost        of        available        energy        is        calculated        as follows.
AUC = Project Cost * E where
( 34)
AUC
= average unit cost (mills/kW*h)
Project Cost = DC+ITC+PTC+PC-t-PHC ($ million)
A7 - PROGRAM DESCRIPTION
The following model logic was developed for evaluation of total project cost estimates for a chosen project
conf iguration.
( 1)       Select an elevation design
(2)       From the given dam neight, evaluate (a)        the total dam volume
height for the dam.
(b)        tne live storage availade to regulate inflows.A-22
(3)       From the total dam volumes, estimate dam costs.
(4)       From the live storage available, evaluate the degree or
river regulation.
(5)       From the degree of river regulation, evaluate long-term
average regulated outflows from each reservoir.
(6)      From the long-term average inflow and the regulated 
long-term average outflow of each reserovir, evaluate
(a)       tne regulated diversion flow between reservoirs
(b)       the unregulated diversion flow between reservoirs
(c)       the regulated power flow from tne head pond
reservoir.
(7)         From the regulated and unregulated diversion flow of
each diversion tunnel, determine the economic diameter
of each diversion tunnel.
(8)       From the economic diameter of the diversion tunnel, 
determine tne diversion tunnel costs.
(9)       From      the      regulated      power      flow,   determine       the economic diameter of the
(a)       power tunnel
(b)       penstock.
From the economic diameter and the length of the powe tunnel, determine the power tunnel costs.
(11)        From the economic
diameter and tne length
of    tne
penstock, determine the penstock costs.A-23
(12)        From     the   economic
sizing        of    the     power tunnel, determine
the
head
loss.
(13)        From     the   economic       sizing        of    the     penstock, determine the
head        loss •
(14)                From the elevation design height of the head pond and 
tne head loss in the power tunnel and penstock, deter
mine the design head of the powerhouse.
(15)        From the regulated power flow and design head,
determine        the        long-term        energy        production        of        the        confi guration.
(16)        From the (given) plant factor, the regulated power flow and the design head, determine the installed capacity of the powerhouse.
(17)        From the installed capacity, determine the powerhouse cost.
(18)        Sum the component costs to determine the total project cost estimate.
Steps 1 to 18 are repeated for a small increment in design height to evaluate the marginal cost of energy production for the given project at that design height. The design height
of the project is adjusted and the marginal cost of project energy is reevaluated at the new design height. The design height continues to be adjusted until the marginal cost of energy production for the project configuration is equal to the marginal cost of grid energy in the Ethiopian power system.A-2 4
The logic layout optimization model is developed in a series of computer program subroutines or modules. A description of these modules is given in the following subsections. The flow chart (Plate A-2) shows the interaction between these
modules.
A7.1 - RESECO
The main module is termed RESECO (acronym for reservoir economics). RESECO contains the overall logic of the model and systematically calls other modules to analyze a specific multireservoir system.
A7.2 - READ
Basic project data are extended into the program by subroutine READ.
A 7.3 - MARGIN
Subroutine MARGIN determines
(a) tne opL.fnum dimensions and costs of the following major project components
-   dams
-   diversion tunnels
-   penstocks
-   power tunnels
-    installed capacities
(b) total project costs.A-25
A7.4 - DEGREG
Parameters determined in subroutine DEGREG relate to the capability of the reservoirs, including
-   live storage available at each reservoir
-   degree of regulation available at each reservoir
-   total live storage available in the system
-   available system degree of regulation.
A7.5 - ITER
Subroutine ITER determines the total live storage required in 
the system to achieve a given system degree of regulation. 
The system live storage is calculated through an interactive
process.
A7.6 - ROUTE
Subroutine ROUTE calculates
(a) the regulated and unregulated flows required to be passed by the interconnection tunnels between
reservoirs
(b) the power flow.
A7.7 - OPTRES
Subroutine OPTRES calculates the optimum reservoir elevation such that one of the following conditions holds.A-24
The logic layout optimization model is developed in a series of computer program subroutines or modules. A description of these modules is given in the following subsections. The flow chart (Plate A-2) shows the interaction between these
modules.
A7.1 - RESECO
The main module is termed RESECO (acronym for reservoir economics). RESECO contains the overall logic of the model and systematically calls other modules to analyze a specific multireservoir system.
A7.2 - READ
Basic project data are extended into the program by subroutine READ.
A7.3 - MARGIN
Subroutine MARGIN determines
(a) the optimum dimensions and costs of the following major project components
-   dams
-   diversion tunnels
-   penstocks
-   power tunnels
-    installed capacities
(b) total project costs.A-25
A7.4 - DEGREG
Parameters determined in subroutine DEGREG relate to the capability of the reservoirs, including
-   live storage available at each reservoir
-   degree of regulation available at each reservoir
-   total live storage available in the system
-   available system degree of regulation.
A7.5 - ITER
Subroutine ITER determines the total live storage required in 
the system to achieve a given system degree of regulation. 
The system live storage is calculated through an interactive
process.
A7.6 - ROUTE
Subroutine ROUTE calculates
(a) the regulated and unregulated flows required to be passed by the interconnection tunnels between
reservoirs
(b) the power flow.
A7.7 - OPTRES
Subroutine OPTRES calculates
the optimum reservoir elevation
such that one of the following conditions holds.A-2 6
- The marginal cost of energy equals the average grid cost of energy.
- The reservoir inflows are completely regulated.
A7.8 - OUTPUT
Subroutine OUTPUT prints a detailed summary of
-   project components for each selected reservoir design elevation
-   tne analysis for the selected and optimum reservoir design elevations.A 7.9 - Example Output
ACRES CONSULTING SERVICES LTD ALELTU PRE-tEASIBILITY STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OE PROJECT SIZING TILIKU • JIDA : PEN TIL TO A
RESERVO II STRUCTURE
NODE RES NAME
3            TILIKU
4               JIDA
GENERAL INPUT DATA
DUN NODE UP NODES
0
3
RESERVOIR ELEVATION (M) =                 2610.00 2605.00 2600.00 2595.00 2590.00 2525.00 2580.00A-28
ACRES CONSULTING SEW ICES LTD ALELTU PRE-FEASIBILITY STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OF PROJECT SIZING TRIXU - JIDA : PEN TIL TO A
RESERVOIR DATA
NODE
RES NAME
DISCH REG
DSEL
NIN LS
HAX LS
U/S LS
U/S LS CST
1
n
AGAT
1.2600
2560.0000
35.3000
84.4600
0.0000
0.0000
TINISHU
0.4700
2560.0000
9.1000
20.3900
0.0000
6.0000
3
TILIKU
5.5700
2560.0000
202.9000
401.1800
0.0000
4.0000
4
JIDA
3.1600
2560.0000
238.2000
707.1200
0.0000
1.3000
5
COMORO
2.4100
2577.0000
49.3000
196.9600
0.0000
0.0000
6
ROB I
4.2900
2588.0000
97.1000
279.2700
0.0000
0.0000
COEFFICIENTS LIVE STORAGE VS ELEVATION
NODE
1
RES NAME
AGAT
Al
0.8400000
A2
1.6020000
*>
to
TINISHU
0.0000000
0.0000000
3 TILIKU
4            JIDA
5 GOMORO
6            ROB I
0.0008890                 3.1501000
0.1281750                 2.4626000
0.0540500                 2.8209000
0.3660800 2.4782000
COEFFICIENTS PERCENT REGULATION VS LIVE STORAGE
NODE             RES NAME
Al
A2
A3
A4
1
2
AGAT
TINISHU
0.2355000
0.1800000
0.0131600
0.0571000
0.0019100
0.0133600
1.3356000
1.3406000
3
4
TILIKU
JIDA
0.4025500
0.1707000
0.0019589
0.0022220
0.0006653
0.0011288
1.0674000
1.0549000
5
6
COMORO
ROB I
0.2477000
0.2894300
0.0091743
0.0042283
0.0027103
0.0003949
1.1940000
1.3607000
COEFFICIENTS DAM VOLUME VS ELEVATION
NODE
RES NAME
1
2
AGAT
TINISHU
Al
1.2230000
A2
0.0420000
A3
1.4250000
3
TILIKU
0.0000000
0.0070000
0.0000000
0.0002243
0.0000000
2.3076000
4
JIDA
5
6
GOMORO
0.2370000
0.0000000
0.0086340
0.0003063
1.3575000
2.7452000
ROB I
0.0000000
0.0011862
2.2892000A-29
ACRES CONSULTING SERVICES LTD                          ALELTU PRE-FEASIBILITY STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OF PROJECT SIZING
TILDCU - JIDA : PEN TIL TO A
RESERVOIR CONNECTIVITY
RESERVOIR CONNECTION                      LENGTH                      NODAL CONNECTIONS
AGAT   -   TINISHU
7.40
1
2
TINISHU     -     TILIKU
4.40
2
3
TILDCU    -    JIDA
2.11
3
4
JIDA  -  COMORO
7.30
4
5
COMORO - WENZ
6.00
5
6
AGAT    -    TILIKU
14.10
1
3
AGAT - JIDA
16.60
1
4
GENERAL COEFFICIENTS
DAM COST
COEFFICIENT
(1)  =
IS.0000
DAM COST
COEFFICIENT
(2)  =
4.0000
DAM COST
COEFFICIENT
(3)  =
0.3000
ENERGY COST =
35.00 (MILS/KWH)
PLANT FACTOR =
0.4000
FLOW FACTOR -
1.4000
COEFF FOR POWER TUNNEL DIAM (TILIKU - A) = 0.362330
COEFF FOR POWER TUNNEL COST (TILIKU - A) = 0.163340
POWER TUNNEL LENGIH (TILIKU - A) = FRICTION FACTOR FOR POWER TUNNEL (TILIKU - A) =
15.51 (KM)
0.018000
COEFF FOR PENSTOCK DIAMETER (PENSTOCK A) =                    0.751450 COEFF FOR PENSTOCK COST (PENSTOCK A) =                   1.578660
PENSTOCK LENGTH (PENSTOCK A) =
3.13 (KM)
FRICTION FACTOR FOR PENSTOCK (PENSTOCX A) =                      0.012000 BASE HEAD FOR POWERHOUSE .PENSTOCK A) =                    1030.00 (M)
COEFFICIENT FOR CAPACITY COST (PENSTOCK A) =
250.00 (»/KU)
BASE POWERHOUSE COSTS ( ACCESS * TRANSMISSION ) (PENSTOCK A) =
22.12 ( M»A-28
ACRES CONSULTING SERVICES LTD ALELTU PRE-FEASIBILITT STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OF PROJECT SIZING TILIKU - JIDA : PEN TIL TO A
RESERVOIR DATA
NODE
RES NAME
DISCH REG
DSEL
MIN LS
MAX LS
U/S LS U/S LS CST
1
n
AGAT
1.2600
2560.0000
35.3000
84.4600
0.0000
0.0000
TINISHU
0.4700
2560.0000
9.1000
20.3900
0.0000
6.0000
3
TILIKU
5.5700
2560.0000
202.9000
401.1800
0.0000
4.0000
4
J IDA
8.1600
2560.0000
238.2000
707.1200
0.0000
1.3000
5
GOMORO
2.4100
2577.0000
49.3000
196.9600
0.0000
0.0000
6
ROB I
4.2900
2588.0000
97.1000
279.2700
0.0000
0.0000
COEFFICIENTS LIVE STORAGE VS ELEVATION
NODE
RES NAME
Al
A2
1
AGAT
0.8400000
1.6020000
2
TINISHU
0.0000000
0.0000000
3
TILIKU
0.0008890
3.1501000
4
JIDA
0.1281750
2.4626000
5
GOMORO
0.0540500
2.8209000
6
ROB I
0.3660800
2.4782000
COEFFICIENTS PERCENT REGULATION VS LIVE STORAGE
NODE
RES NAME
Al
A2
1
AGAT
0.2355000
0.0131600
2
TINISHU
0.1800000
0.0571000
A3
0.0019100
0.0133600
3
TILIKU
0.4025500
0.0019589
4
JIDA
0.1707000
0.0022220
0.0006653
0.0011288
A4
1.3356000 1.3406000 1.0674000 1.0549000
5
GOMORO
0.2477000
0.0091743
0,0027103
6
ROB I
0.2894300
0.0042283
0.0003949
1.1940000
1.3607000
COEFFICIENTS DAM
VOLUME VS ELEVATION
NODE
RES NAME
Al
A2
1
AGAT
1.2230000
0.0420000
2
TINISHU
0.0000000
0.0000000
3
TILIKU
0.0070000
0.0002243
A3
1.4250000
0.0000000
2.3076000
4
JIDA
0.2370000
0.0086340
1.3575000
jr
GOMORO
0.0000000
0.0003063
2.7452000
6
ROB I
0.0000000
0.0011862
2.2892000A-29
ACRES COMSULTING SERVICES LTD ALELTU PRE-FEASIBILITY STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OF PROJECT SIZING TILIXU - JIDA : PEN TIL TO A
RESERVOIR CONNECTIVITY
RESERVOIR CONNECTION
LENGTH
NODAL CONNECTIONS
AGAT - TINISHU
7.40
1
2
TINISHU - TILIKU
4.40
2
3
TILIKU - JIDA
2.11
3
4
JIDA - GOMORO
7.80
4
5
COMORO - WENZ
6.00
5
6
AGAT - TILIKU
14.10
1
3
AGAT - JIDA
16.60
1
4
GENERAL COEFFICIENTS
DAN      COST      COEFFICIENT      (1)      =      15.0000
DAN      COST      COEFFICIENT      (2)      =      4.0000
DAN COST COEFFICIENT (3) = 0.3000
ENERGY COST =                35.00 (NILS/KWH)
PLANT FACTOR »               0.4000
FLOW FACTOR =              1.4000
COEFF    FOR    POWER    TUNNEL    DIAN    (TILIKU    -    A)    =    0.362330
COEFF FOR POWER TUNNEL COST (TILIKU - A) = 0.163940
POWER TUNNEL LENGTH (TILIKU - A) = FRICTION FACTOR FOR POWER TUNNEL (TILIKU - A) =
15.51 (KM)
0.018000
COEFF FOR PENSTOCK DIAMETER (PENSTOCK A) =                    0.751450 COEFF FOR PENSTOCK COST (PENSTOCK A) =                   1.578660
PENSTOCK LENGTH (PENSTOCK A) =
3.13 (KN)
FRICTION    FACTOR    FOR    PENSTOCK    (PENSTOCK    A)    =    0.012000 BASE HEAD FOR POWERHOUSE (PENSTOCK A) =                    1030.00 (M)
COEFFICIENT FOR CAPACITY COST (PENSTOCK A) =
250.00 iS/KW)
BASE POWERHOUSE COSTS ( ACCESS ♦ TRANSMISSION ) (PENSTOCK A) =
22.12 ( M$ACRES CONSULTING SERVICES LTD
A-30
ALELTU PtE-FEASIBILITY STUD!
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OF PROJECT SIZING
TILIKU - JIDA : PEN TIL TO A
RESULTS FOR ELEVATION 2610.00 (M)
RESERVOIR
NUMBER
DAN
VOLUME
DAM LIVE DEGREE TUNNEL
COST STORAGE REGULATION COST
TUNNEL
DIAMETER
UNREG
FLOW
REG
FLOW
3                  1.8746             23.0654           199.9111             0.7942              0.0000              0.0000             0.0000           13.7300 4               12.5979               82.5108         1957.4328             1.0000              2.2325              4.0253            -1.1466              9.3066
SYS               14.4725             105.5762         2157.3439             1.0000              2.2325
PENSTOCK DESIGN
DIAM (M.;=
2.3575 HEAD
LOSS (M.)=
22.0114
COST (Ml)=
POUER TUNNEL DESIGN
DiAM (M.) =
3.1992 HEAD
LOSS (M.)=
35.5980
COST (Ml) =
15.5237
26.0242
RESULTS FOR ELEVATION 2605.00 (M)
RESERVOIR DAM
NUMBER VOLUME
DAM LIVE DEGREE TUNNEL
COST STORAGE REGULATION COST
TUNNEL
DIAMETER
UNREG            REG
FLOW FLOW
3
4
1.4716
10.4008
19.4638
73.3181
143.4486
1510.0957
0.6836
1.0000
0.0000
2.3455
0.0000
4.1298
0.0000
-1.7626
13.7300
9.9226
SYS              11.8723               92.7819       1653.5443               1.0000              2.3455
PENSTOCK DESIGN
POWER TUNNEL DESIGN
DIAN (M.)=
DIAM (M.)=
2.3575 HEAO LOSS (M.)= 22.0114 COST (Ml)= 15.5237
3.1992 HEAD LOSS iM.)= 35.5980 COST (Ml)= 26.0242
RESULTS FOR ELEVATION 2600.00 (M)
RESERVOIR
NUMBER
DAM
VOLUME
DAM
COST
LIVE DEGREE
STORAGE REGULATION
TUNNEL
COST
TUNNEL UNREG
DIAMETER FLOW
REG
FLOW
3
4
1.1230
3.4035
16.1940
63.6940
98.9830
1129.8902
0.5964
1.0000
0.0000
2.4336
0.0000
4.2094
0.0000
-2.2478
13.7300
10.4078
SYS                9.5266                79.3879     1223.9733                 1.0000              2.4336
PENSTOCK DESIGN
POWER TUNNEL DESIGN
DIAM (M.)= 2.3575
DIAM (M.) = 3.1992
HEAD LOSS (M.)= 22.0114
HEAD LOSS (M.)= 35.5980
COST (Ml)= 15.5237
COST (Mi) = 26.0242A-31
ACRES CONSULTING SERVICES LTD                           ALELTU PRE-FEASIBILITY STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OE PROJECT SIZING
TILIXU - JIDA : PEN TIL TO A
RESULTS FOB ELEVATION 2595.00 (M)
RESERVOIR
NUMBER
DAM
VOLUME
DAM                   LIVE DEGREE
TUNNEL          TUNNEL                 UNREG                  REG
COST
STORAGE
REGULATION
COST
DIAMETER
FLOW
aow
3
4
0.8271
6.60%
13.2808
53.3547
64.9950
0.5299
0.0000
2.2957
0.0000
4.0840
0.0000
12.6011
8
13.2523
1.0000
-2.1607
9.6498
SYS                7.4367             67.1355         878.2473                 0.9178
2.2957
PENSTOCK DESIGN            DIAM
POWER TUNNa DESIGN DIAM
(M.)=        2.2724        HEAD        LOSS        (M.)= (M.)= 3.0837 HEAD LOSS (M.)=
22.2832
36.0375
COST (M$)= 14.4231
COST (M»)= 24.1789
RESERVOIR DAM
NUMBER VOLUME
RESULTS FOR aEVATION 2590.00 (M)
DAM LIVE DEGREE TUNNa COST STORAGE REGULATION COST
TUNNEL
DIAMETER
UNREG
aow
REG
FLOW
3
0.5816
10.7466
39.9937
0.4809
0.0000
0.0000                 0.0000                 11.1065
4
5.0229
44.0373
556.3680
0.9142
2.0687
3.8687               -1.3271
8.4279
SYS
5.6045
54.7839
596.3616
0.8089
2.0687
PENSTOCK DESIGN                DIAM (M.)»                 2.1527     HEAD LOSS (M.)= POWER TUNNa DESIGN                    DIAN (M.)=                 2.9212     HEAD LOSS (M.)=
RESULTS FOR ELEVATION 2585.00 (M)
22.6891
COST
(H$)=
12.9438
36.6940
COST
(M) =
21.6987
RESERVOIR DAM
NUMBER VOLUME
MM LIVE DEGREE
TUNNEL TUNNEL
UNREG
REG
COST           STORAGE      REGULATION         COST              DIAMETER aOU
aou
3
0.3843
8.6102            22.5197
0.4467
0.0000              0.0000
4
3.6480
0.0000               9.4335
34.5057
355.1161
0.7834
1.7842
3.5807
-1.3391
6.9456
SYS
4.0323
43.1160
377.6358
0.6871
PENSTOCK DESIGN
DIAM
(MJ=
2.0072 h;
1.7842 LOSS      (M.)=
POWER TUNMEL DESIGN
DiAM
23.2251
37.5608
COST (ND®
(M.J=
2.7238 HI
LOSS (M.)=
COST (M4)=
11.2535
18.3649A-32 ACRES CONSULTING SERVICES LTD                     ALELTU PRE-FtASIBILITY STUDY
ALELTU PRE’EEASIBILITY STUDY OPTIMIZATION GF PROJECT SIZING
TRIXU - JIDA : PEN TIL TO A
RESULTS FOR ELEVATION 2580.00 (M)
RESERVOIR
DAM
DAM
LIVE
DEGREE
TUNNEL
TUNNEL
UNREG
REG
NUMBER
VOLUME
COST
STORAGE
REGULATION
COST
DIAMETER
FLOW
FLOW
3
0.2324
6.8863
11.1503
0.4244
0.0000
0.0000
0.0000
7.1250
4
2.4906
25.5594
204.9839
0.6262
1.3410
3.0787
-0.5266
4.7611
SYS               2.7230            32.4457           216.1342            0.5189              1.3410
PENSTOCK DESIGN           DIAM   (M.)=            1.7797 HEAD LOSS (M.)=                  24.1762    COST (Ml)=             8.8474
rovn TUNNEL DESIGN                 DIAN   (M.)=           2.4151 HEAD LOSS (NJ=
39.0989    COST (Ml)=           14.8310
RESULTS FOR ELEVATION 2598.35 (M)
RESERVOIR DAM
NUMBER VOLUME
DAM
COST
LIVE DEGREE TUNNEL STORAGE REGULATION COST
TUNNEL
DIAMETER
UNREG REG
FLOW FLOW
3               1.0196             15.1920           86.6824              0.5724              0.0000             0.0000             0.0000            13.7153 4               7.7889              60.4596     1018.5537                1.0000             2.4551             4.2287            -2.3760             10.5273
SYS               8.8085             75.6517     1105.2361                0.9989              2.4551
PENSTOCK DESIGN          DIAM (M.)=              2.3564       HEAD LOSS (M.)=          22.0148       COST (M1) =      15.5094 POWER TUNNEL DESIGN          DIAM (M.)=              3.1977       HEAD LOSS (M.)=          35.6035       COST (Mf)=        26.0003A-33
ACRES CONSULTING SERVICES LTD
ALELTU PRE-FEASIBILITY STUDY
ALELTU PRE-FEASIBILITY STUDY OPTIMIZATION OF PROJECT SIZING TRIXU - JIDA : PEN TIL TO A
SUMMARY OF RESULTS
ELEVATION
(K)
DAM COST
TUN COST
PTUN COST
PSTX COST
PWRH COST
TOTAL COST
(IM)
(IM)
(M)
(IK)
(IM)
(IM)
2610.00             105.5762                 2.2325               26.0242                15.5237
2605.00               92.7819
2.3455               26.0242                15.5237
94.3972 243.7538
94.1288 230.8041
2600.00               79.8879                 2.4336               26.0242                15.5237                93.8604                217.7298
2595.00 67.1355
2590.00 54.7839
2585.00 43.1160
2580.00 32.4457
2.2957               24.1789                14.4231
87.6689              195.7021
2.0687 21.6987 12.9438 79.6154 171.1104
1.7842 18.8649 11.2535 70.7014 145.7200
1.3410               14.8310
3.3474                58.5811                116.0462
2598.35               75.6517                 2.4551               26.0003                15.5094                93.6945                213.3110A-34
W3ES CONSULTING SERVICES LTD ALELTU PRE-FEASIBILITY STUDY
ALELTU PK-EEASBILITY STUDY
OPTIMIZATION OF PROJECT SUING
TILIXU - JIDA : PEN TIL TO A
SUMMARY OF RESULTS
ELEVATION
(M)
NET HEAD
CAP COST
ANN EGY
ANN BEN
CAPACITY
(N)
AUS COST
AVG COST
KARG COST
(N)
(»N/YI;
(GW)
•$N)
($/KW)
(MILS/KVH)
(MILS/KWH)
BEN/COST
RATIO
2610.00 1009.39
2605.00 1006.14
2600.00 1002.39
29.25              1013.04
27.79              1009.23
26.22              1005.51
23.57                913.73
20.61 305.35
17.55 680.92
35.46 289.11
35.32 233.04
35.19 236.96
32.16 262.20
23.20 229.93
23.33 194.33
843.12
301.31
753.74
746.40
744.02
749.88
23.93                410.07               1.2079
27.54                417.31               1.2710
26.08                 417.%                1.3423
2595.00
2590.00
2585.00
997.93
993.12
987.96
25.65
25.57
25.77
25.61 1.3645
26.63 1.3633
20.14 1.3531
2530.OG                 931.72                     13.97               511.04                  17.39                145.84                 795.69                  27.34                  22.15                1.2799
Z98.35                1001.14
25.69               1003.19
35.11                286.30
745.07
25.61
24.32                1.3669I ADI t A. I
Kt  Sill  IS  UF  INI  11  Al
LAmil MUOtl RUHS
l>«sc i lul loti
Unit
3A
MA
5A
45A
34 5A
56C
56C
568
56A
5689C
56890
5689A
9G
Wl
6896
68911
(1)
(2)
(31
(4)
(5)
(6)
(7)
(81
(91
(10)
(ID
(12)
(13)
(14)
(IS)
(16)
full Supply iovol
a
2 574.U
2 578.0
2 600.0
2 597.5
2 582.2
2 592.0
2 592.0
2 592.0
2 592.1
2 582.5
2 582.5
2 582.5
2 579.1
2 577.2
2 579.1
2 577.5
I IvU SI04 <XJM
57.6
III.7
191.1
290.3
217.6
824.0
625.6
826.2
628.4
1 282.5
1 283.9
1 281.3
231.1
190.3
935.1
815.2
Dvj ol Ruyulal lun
1
97.9
99.5
01.1
92.1
73.6
99.8
99.9
99.9
99.9
99.9
99.9
99.9
93.7
88.1
99.9
95.0
Huju1 d 1 ad f 1 co
1.06
2.02
4.71
6.22
5.76
14.86
14.87
14.87
14.88
22.64
22.65
22.64
4.52
4.25
16.69
16.01
Pu««f 1 annul
a
0.61
1.06
1.53
1.72
1.68
2.58
2.56
2.56
2.50
3.09
3.07
2.99
1.52
1.52
2.66
2.68
0I.M1OI
Pufibfoch Dldnutur
a
1.53
2.02
2.91
3.27
3.17
4.76
4.76
4.87
4.76
5.70
5.70
5.70
3.97
2.78
5.00
4.91
l«ul lludd
a
1 029.6
1 036.7
1 024.7
1 026.4
1 046.1
919.9
815.3
935.5
1 032.2
917.3
933.1
1 034.1
916.0
786.9
925.1
792.5
tout yy
GWh/yr
79.6
153.0
352.3
466.1
440.3
998.7
994.3
1 016.4
1 122.3
1 517.5
1 544.2
1 705.4
302.7
244.7
1 128.0
927.1
( opaci t y
MW
18. 17
34.93
60.43
106.42
100.53
228.02
227.00
232.06
256.24
346.47
352.60
389.37
69.12
55.88
257.54
211.68
Uaas
lx IQ6
28.53
59.01
49.25
64.66
78.82
62.58
62.68
62.71
62.85
99.82
99.89
99.75
26.06
23.23
75.81
69.12
Sui Ixu I urinal $
UI06
0.00
1.88
0.00
2.35
11.18
2.75
1.69
2.75
2.75
26.49
26.50
26.48
0.00
0.00
24.10
23.37
Huvoi lutinul
IxlU6
0.53
0.83
8.27
10.35
1.88
13.16
16.38
16.68
21.22
18.72
23.72
30.16
4.42
3.27
12.89
9.65
Pt»IH tuck
S a 10*
2.36
4.70
6.47
10.76
10.09
11.71
11.71
11.31
22.74
16.80
16.22
32.58
6.96
3.14
21.30
9.77
Huwur house
lx IO6
21.26
25.45
36.63
43.32
41.85
74.30
74.04
75.08
80.78
103.91
105.20
114.06
42.37
38.83
89.46
77.78
lulol Cost
IxlU6
52.68
91.26
72.86
131.44
143.61
164.49
166.50
168.53
190.30
265.73
271.53
303.04
49.81
68.46
223.58
189.68
Annual Cost
6
|xlO /yr
6. 54
10.99
6.77
15.83
17.32
19.61
20.05
20.29
22.92
32.00
32.70
36.47
9.61
8.24
26.92
22.64
Annual Uunol1t
6
ixl0 /y<
2.39
4.59
10.57
13.96
13.21
29.96
29.83
30.49
33.67
45.53
46.33
51.16
9.06
7.34
33.84
27.01
A,y (opacity Cust
1/kW
2 900
2 613
90C
1 235
1 431
721
733
726
743
767
770
778
1 153
1 225
668
896
Awcj tnurijy Cos 1
al 1Is/kW-h
79.72
71.63
24.89
33.96
39.33
19.83
20.17
19.97
20.42
21.09
21.17
21.40
32.75
33.69
23.87
24.64
Ah j t nut yy Cos 1
al Ils/kWh
66.87
77.69
19.15
30.00
30.00
30.00
30.00
30.00
29.34
29.73
29.64
28.76
30.00
30.00
29.96
50.00
UA Hallo
-
0. 38
0.42
1.21
0.88
0.76
1.51
1.49
1.50
1.47
1.42
1.42
1.40
0.94
0.89
1.26
1.22A-34
■M3E3 CONSULTING SciVICES LID ALELTU P8E-FEAS3ILITY STUD!
ALELTU PBE-cEA3ISILITr STUDY uPTINIZATION OF PROJECT SIZING TILDOJ - J IDA : PEN TIL TO A
SUMMARY OF RESULTS
ELEVATION
(M)
me: head
(N)
CAP COST
itt/YS)
ANN EGY
(GUH)
ANN BEN
(IN)
CAPACITY
(MV)
AUG COST
il/KV)
AUG cos:
(MILS/KUH)
MARG COST
(MILS/KWH)
bem/cos:
RATIO
2610.00 1009.39
2605.00 1006.14
2600.00 1002.39
29.35              1013.04
27.79              1009.23
26.22              1005.51
23.57                913.73
20.61 305.35
35.46                289.11                 343.12
35.32                233.04                 301.31
35.19                236.96                 753.74
32.16 262.20 746.40
23.20 229.93 744.02
23.98               410.07               1.2079
27.54               417.31                1.2710
26.03                417.%                1.3423
2595.00
2590.00
997.93
993.12
25.65
25.57
25.61 1.3645
26.63 1.3633
Z85.00
987.96
17.55
630.92
23.33
194.33
749.83
25.77
20.14
1.3581
2530.00
931.72
13.97
511.04
17.39
145.84
795.69
27.34
TT '.e
*1J
1.2799
2598.35                1001.14
25.69               1003.19
35.11                286.30
745.07
25.61             •a^aUaa                1.3669AlJlt A,
Hl MH IS Of INI I I Al LAYOUl MOOtI RUNS
Dus<r Ipl Icmi
Unll
3A
34A
5A
45A
34 5*
56C
5«3
56A
5669C
56890
5689A
9G
®l
689G
68911
(II
(2)
<31
(4)
(5)
(6)
(7)
<8>
(91
(10)
(II)
(12)
(13)
(14)
(15)
(16)
full Supply Lovul
■
2 574 <,0
2 578.0
2 600.0
2 597.5
2 582.2
2 592.0
2 592.0
2 592.0
2 592.1
2 562.5
2 582.5
2 562.5
2 579.1
2 577.2
2 579.1
2 577.5
I Iva SIcmojm
Mh>3
51.6
III.7
191.1
290.3
217.6
824.0
825.6
626.2
626.4
1 282.5
1 263.9
1 281.3
231.1
190.3
935.1
815.2
Dwy ul Regulation
97.9
99.5
81.1
92.1
73.6
99.8
99.9
99.9
99.9
99.9
99.9
99.9
93.7
88.1
99.9
95.0
l<U <J U 1 d 1 U(J fl CM
.Vs
1.06
2.02
4.71
6.22
5.76
14.86
14.87
14.67
14.68
22.64
22.65
22.64
4.52
4.25
16.69
16.01
Pcmuf 1 annul
■
0.81
1.06
1.53
1.72
1.68
2.58
2.56
2.56
2.50
3.09
3.07
2.99
1.52
1.52
2.66
2.68
UI^buIui
Punstock Dlaroutur
HI
1.53
2.02
2.91
3.27
3.17
4.76
4.76
4.87
4.76
5. 70
5.70
5.70
3.97
2.78
5.00
4.91
Nut Ikiod
HI
1 029. 6
1 036.7
1 024.7
1 026.4
1 046.1
919.9
815.3
935.5
1 032.2
917.3
933.1
1 034.1
916.0
786.9
925.1
792.5
GN-h/yr
19.6
153.0
352.3
466.1
440.3
998.7
994.3
1 016.4
1 122.3
1 517.5
1 544.2
1 705.4
302.7
244.7
1 128.0
927.1
Capac 11y
HW
16. 17
34.93
80.43
106.42
100.53
228.02
227.00
232.06
256.24
346.47
352.60
389.37
69.12
55.88
257.54
211.68
l)«m^
Im IO6
28.53
59.01
49.25
64.66
78.82
62.58
62.68
62.71
62.85
99.82
99.69
99.75
26.06
23.23
75.61
69.12
IxlO6
0.00
1.88
0.00
2.35
11.16
2.75
1.69
2.75
2.75
26.49
26.50
26.48
0.00
0.00
24.10
23.37
P<mui I annul
Im IO6
0.55
0.83
8.27
10.35
1.88
13.16
16.38
16.68
21.22
16.72
23.72
30.16
4.42
3.27
12.89
9.65
IO6
2.36
4. 70
8.47
10.76
10.09
11.71
11.71
11.31
22.74
16.80
16.22
32.58
6.96
3.14
21.30
9.77
PcMUf IiuuSm
lx IO6
21.26
25.45
36.83
43.32
41.85
74.30
74.04
75.08
80.78
103.91
105.20
114.06
42.37
38.83
89.48
77.78
lutdl Cost
Im IO6
52.68
91.26
72.66
131.44
143.81
164.49
166.50
168.53
190.30
265.73
271.53
303.04
49.81
68.46
223.58
189.66
Annual Cost
6
Im IO /yr
6. 34
10.99
8. 77
15.83
17.32
19.81
20.05
20.29
22.92
32.00
32.70
36.47
9.61
8.24
26.92
22.64
Annual Banal 1t
6
i*IO /yf
2.39
4.59
10.57
13.98
13.21
29.96
29.63
30.49
33.67
45.53
46.33
51.16
9.08
7.34
33.64
27.81
Avy LapaC 1 1 y Coil
l/k»t
2 ‘>00
2 613
906
1 235
1 431
721
733
726
743
767
770
778
1 155
1 225
868
696
Av<j lnu(<jy Cost
•1 1 Is/kM’li
79. n
71.83
24.89
33.96
39.33
19.63
20.17
19.97
20.42
21.09
21.17
21.40
32.75
33.69
23.87
24.64
Mui j £nu< yy Cos t
ml 1 |s/ktf*t)
66.87
77.69
19.15
30.00
30.00
30.00
30.00
30.00
29.34
29.73
29.64
28.76
30.00
30.00
29.96
30.00
HA Kat Io
-
0.38
0.42
1.21
0.88
0.76
1.51
1.49
1.50
1.47
1.42
1.42
1.40
0.94
0.89
1.26
1.22iadli a. 2
IKSill  IS  (N  FIHAI
IA10UI MOit I RUHS
Doser 1 pI Ion Unit
5A«
(II
6A
(2)
%A 568A 561
(3> <41 ?5
B9A I
89G
(61
456A
171
45689A          256A«»          7E°«
56.I2A            5689.I2A        5689.I4A
(6)
(9)                  (10)
(III
7l2)
(13)
full Supply level
■
2 600.0
2 595.1
2 598.4
2 597.4
Dam Vuluaw
2  598.7
Mm*
2 599.0
l.l
2 598.7
6.0
2 598.6
2 628.0
8.8
9.6
|o  .7
2 500.0
2 601.2
2 600.2
2 596.9
I Ivo Slur agu
Ha*
1.8
99.0
8.9
10.7
706.2
1.6
0.1
I 105.2
| JO5.2
I    579.2
10.1
11.7
10.0
D«*j ol Rtejulallon
4/2.9
1
59.64
1 127.1
1 596.1
100.00
143.0
1.00
1 325.6
1 800.9
1 883.9
Hegu1 a 1 wd flow
100.00
100.00
10 0.00
3.32
100.00
8. 16
100.00
100.00
13.72
16.14
20   .40
100.00
-
100.00
100.00
■
6.69
100.00
Power lunnwl
1.74
14.19
20.88
2.56
2.30
6.70
3.20
5.4)
).   79
17.71
24.41
26.60
Dlaawlur
2.35
3.25
5.85
-
2.55
5.66
4.09
4.25
Penstock 1)1 .mm 1 ar
■
1.28
1.89
Mel lh«ad
2.36
2.53
•
2.  79
969.4
1.75
9U0.4
2.39
2.82
2.50"
I 001.|
| 001.8
I    004.6
1.75
2.63
3.02
1 007.1
3.13
Lnur gy
Ot-h/yr
240.2
950.6
584.2
1 001.7
1 004.9
i ooi.r
786.5
1 005.4
1 006.7
Capaclly
I 005.2
I 181.3
I    496.1
MW
68.50
464.9
1 038.6
166.80
1 552.7
168.0
505.2
286.50
357.10
42  7.50
1 300.5
1 796.0
1 956.3
132.70
296.40
457.40
46.00
110.00
571.10
512.50
558.30
Dears
Im IO6
17.49
54.01
Sni lace tunnels
75.65
86.22
lx IO6
94   .93
24.48
62.42
101.58
15.58
2.46
8.55
18    56
27.58
116.28
135.60
120.61
Power lunnul
lx IO6
7.71
4. 18
22.02
3.73
20.05
1.03
-
26.00
29.89
36   .56
2.95
20.84
31.43
Puns loch
lx IO6
4.60
7.25
9.95
26.77
57.27
2.49
25.51
17.83
21   .81
2.99
32.56
42.62
45.8/
Power house
IxlO6
59.25
8.37
65.80
15.97
22.25
2.21
8.37
93.69
12  9.00
19.50
25.42
27.36
total Cost
lx IO6
106.40
69.06
63.26
149.76
96.22
131.47
9.62
213.31
248.89
50 0.86
57.60
114.91
150.26
161. 70
107.53
225.12
312.60
30.95
96 50
265.68
374.74
596.97
Annual Cost
6
lx to /yr
8.32
18.05
Annual Uonuflt
6
IxlO /yr
25.09
29.9/
8.41
56  .25
12.95
27.11
20.45
37.64
3.72
11.62
34.43
35. 11
52  .43
46.13
46.60
Avg Capacity Cost
l/KN
41.55
1 008
16.27
36.35
53.64
5.88
15.48
62.86
745
4 38
70 4
68.47
Av J Lliurgy Cost
890
45.52
mlllS/kW'h
34.63
811
760
30.87
715
644
8/7
770
7)1
693
Moi g lnur <jy Cost
■Ills/kWIi
25.61
25.37
25.54
24   .18
27.85
26.10
27.47
24.56
22.14
30. 17
26.4/
U/V Hallo
24.62
30.46
-
1.01
50  .22
25.13
25.82
33.84
24.44
29.93
1.13
-
-
23.23
28.29
26.22
1.37
1.58
|.  45
1.26
1.34
1.43
1.58
1. 16
1.21
1.39
1.47
• Nunop 11mai.
■■ Situ 2a - Scheme 2.
■••Situ 7a Scheme |,
Wosurbl data a< u given except whor u underlined. Robl-Gunxxo date ai w given except were underlined.APPENDIX B
TABLE OF CONTENTS
LIST   OF   TABLES LIST OF PLATES
Page
Bl - INTRODUCTION----------------------------------------------------------------------------- B- 1
B2 - DATA AVAILABILITY AND REVIEW------------------------------------------------- B- 3
B2.1 - Hydrometric Station Locations and
Records--------------------------------------------------------------------  B- 3
B2.2 -        Streamflow Data Analysis------------------------------------------------------ B-17
B2.3 -        Rainfall Data             Analysis------------------------------------------------  B-25
B3 - PRELIMINARY STREAMFLOW SEQUENCE ANALYSIS ------------------------  B-28
B3.1 -
Evaluation 
of Discharge Stations -----------------------------------  B-28
B3.2 -
Generation 
of Inflow Sequences-------------------------------------  B-31
B3.3        -        Assessment        of        the        Regulation        Potential
of Each Reservoir--------------------------------------------------------  B-31
B4 - FINAL STREAMFLOW SEQUENCE ANALYSIS ------------------------------------  B-33
B4.1 - Derivation of Synthetic Flow Sequences--------------------------------------      B-34
B5 - EVAPORATION ANALYSES-------------------------------------------------------------  B-39
B6 - RESERVOIR REGULATION ANALYSIS ----------------------------------------------  B-52
B7 - FLOOD FLOW STUDIES----------------------------------------------------------------- B-53
B7.1 -
General --------------------------------------------------------------------------  B-53
B7.2 -
Frequency Curves--------------------------------------------------------------- B-60
B7.3 -
Homogeneity Test -------------------------------------------------------------  B-62
B7.4 -
Flood Index Factors ------------------------------------------------------------ B-62
B7.5 -
Mean Annual Floods ----------------------------------------------------------  B-63
B7.6 -
Peak Flood Calculations-------------------------------------------------------  B-63
B7.7 -
Inflow Hydrograpns -----------------------------------------------------------  B-65
B8 - RESERVOIR SEDIMENTATION ------------------------------------------------------  B-67
B9 - EVALUATION OF HYDROLOGIC ANALYSES -----------------------------------  B-67
B9.1 - General ---------------------------------------------------------------------------  B-67
B9.2 - Inflow Sequences ---------------------------------------------------------------  B-69
B9.3 - Flood Flows ---------------------------------------------------------------------  B-70
PLATESAPPENDIX B
LIST OF TABLES
Number             Title
B. 1                    Streamflow Records
B. 2                    Rainfall Records
B.3                     Discharge Record Corelations
3.4                     Complete and Extended
Streamflow Records
B. 5                   Rainfall Corelations
B.6                     Comparison of Chacna and 
Muger Streamflow Parameters
B.7                    Centroid         Distances         of         Subbasins in Preliminary Hydrology Study
B.8                    Montnly         Inflow         Sequences of Subbasins
B.9                     Reservoir Evaporation Losses B. 10                  Example Jida Reservoir
Regulation Computer Runs
B. 11                 Reservoir-Regulation for Final Model Runs
B. 12                 Results       of       Flood Hydrology Analysis
B. 13                  Flood Index Factors B. 14                 Computed Peak Flows
RelationshipsAPPENDIX B
LIST OF PLATES
Number           Title
B-l                   Hydrologic Data Base
B-2                  Hydrometric Recording Station B-3                  Hydrology Studies-DetaiIsAPPENDIX B
HYDROLOGICAL STUDIES
Bl - INTRODUCTION
This appendix contains a description and the results of the hydrological studies carried out for the Aleltu project. 
These studies were carried out in two phases as hydrologic
data were required initially to facilitate operation of the
layout optimization model and at a later stage for execution 
of the prefeasibility studies.
-    Initially, no rainfall data were available, and streamflow records only were utilized to provide a data base for preliminary hydrologic analyses. A simplified spatial relationship was defined between project subbasins and relevant gauging stations. On this basis, monthly reser
voir inflow sequences were derived.
-   As more data became available, including rainfall data, further studies were undertaken to refine the results of
the preliminary analyses. Evaporation losses from the proposed reservoirs were determined and flood hydrology studies were carried out. A qualitative assessment of potential reservoir sedimentation was undertaken.
A numDer of hydrologic methods were used and various analyses were carried out to obtain reliable series of monthly inflow sequences for the subDasins of the project. In orcer to 
maintain a perspective on the approach and methodologyAPPENDIX B
HYDROLOGICAL STUDIES
Bl - INTRODUCTION
This appendix contains a description and the results of the hydrological studies carried out for the Aleltu project. 
These studies were carried out in two phases as hydrologic
data were required initially to facilitate operation of the
layout optimization model and at a later stage for execution 
of the prefeasibility studies.
- Initially, no rainfall data were available, and streamflow records only were utilized to provide a data base for preliminary hydrologic analyses. A simplified spatial relationship was defined between project subbasins and relevant gauging stations. On this basis, monthly reser
voir inflow sequences were derived.
- As more data became available, including rainfall data, 
further studies were undertaken to refine the results of
the preliminary analyses. Evaporation losses from the proposed reservoirs were determined and flood hydrology studies were carried out. A qualitative assessment of potential reservoir sedimentation was undertaken.
A number of hydrologic methods were used and various analyses were carried out to obtain reliable series of monthly inflow sequences for the subbasins of the project. In order to 
maintain a perspective on the approach and methodologyB-2
descrioea      in      Sections      B2      to      B6,      a      point      form      summary      of      study steps and results is presented oelow.
(a) No streamflow data are available at the sites under
study in the Aleltu project. Available streamflow recording stations are located at the (more drier) eastern side of the project area (Chacha) and at the (more wetter) western side of the project area (Muger). 
Additional stations are located outside the project area.
(d) No correlation exists among the Chacha and Muger stations and correlations with outside stations is not strong.
(c) There are no rainfall stations witnin the subbasins but
a number are located around tne peripnery of the project area. The availaDle rainfall records are mostly incom plete, intermittent and snort.
(d) No consistent correlative relationships exist between 
any pair of rainfall stations. This is likely due to spot rainfall, typical of convective thunderstorms and line squall activity; therefore, longer records cannot be used to fill in or extend the shorter records.
(e) No reliaole correlative relationsnips between streamflow records and any of the rainfall records could be derived. The density of rainfall station locations is insufficient (for the type of rainfall experienced) to extend or fill in streamflow records from rainfall recordings.
f) As a result of tne absence of reliable correlations
among any of the streamflow or rainfall records, synthe tical streamflow sequences were derived for the suboasins.READ
PLATE A
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY ALELTU HYDROELECTRIC PROJECT
COMPUTER MODEL FLOW CHARTi
4r
* FW M
r» 4 k t r a* ’ *
• ♦ « ►*-> **
< W 1 • i«M » n* * •«* &
-e
*     »   < MS
♦
»< t*WMrf
*•♦ W
•* AM *
< *rvr
MWV"»■•
r. in < I . *■*
»     • ■ * »,    «i
.•ent.
<
iC*B-3
(g) The method of synthetizing flow sequences uses
-   annual isohyetal maps to obtain an estimate of the mean annual rainfall in each subbasin
-   probabilistic methods to derive a rainfall/runoff relationship from data of the Chacha and Muger stations
- a statistical, single-step, sequential, simulation method with a random element to derive streamflow values for each subbasin from the monthly flow variability recorded at the Chacha station.
(h) The results of the analyses are considered to be accept able for examining alternative development schemes at prefeasibility level. The reference hydrology will, 
however, require extensive review once actual streamflow observations at the top ranking sites have been 
collected for a number of years.
B2 - DATA AVAILABILITY AND REVIEW
B2.1 - Hydrometric Station
Locations and Records
The locations of streamflow and rainfall stations of interest in the Aleltu study are shown on Plate B-l. Tne recording periods of these stations are shown on Plate B-2. The individual records of the streamflow and rainfall gauging stations are shown in Taoles B.l and B.2.table   Pl   :   historic   STREANFLOU   sequence    foe    peressa    r.uer    at    pepre
DRAINAGE AREA«211 RmJ
BIBHAN IN MILLION CUBIC METRES
JAN
FEB MAR
ABRIL
MAY
JUNE
JULY
AUG
SEPT
OCT
NdV
1962
0.32
0.27
0.50
0.55
0.60
0.91
—
......
1963
0.43
1964
0.20
0.29
0.35
o.io
1.15
2.10
22.79
1.02
45.63
27.36
19.36
65.69
1.73
0.00
1.30
1965
0.22
0.71
0.51
0.65
1.12
1.12
0.63
0.35
0.04
2.13
0.91
42.50
49.04
12.20
1966
0.47
0.60
0.62
1.12
1.13
0.06
1.13
1.69
24.35
0.99
0.10
0.35
1967
5.63
1.20
0.61
2.02
0.52
1.04
1.42
2.87
50.38
22.57
I960
50.06
0.87
1.0(1
1 .47
29.92
0.60
1.41
DEC
0.75
0.09
0.23
2.90
0.63
1969
2.90
1.15
0 . 19
1.32
1 .no
1.44
1.30
1.00
1.32
60.92
6.24
57.83
7.21
14.40
2.07
0.42
34.53
3.40
1970
3.14
0.41
0.27
0.67
0.37
0.64
0.54
109.06
3.71
0.53
1971
0.29
0.15
0.20
0.40
0.70
34.05
5.53
63.50
7.57
0.3*3
0.93
1.32
2.0(3
0.42
1972
22.23
110.01
0.25
0.38
0.34
0.40
0.27
0.36
0.34
0.90
9.24
0.41
1973
0.36
0.40
0.33
0.27
0.24
H.40
48.06
12. 15
1974
0.06
0.39
0.43
1975
0.26
0.33
0.40
0.52
0.53
0.51
0.40
20.6/i
0.57
60.22
42.17
19.97
0.60
0.46
0.33
0.25
52.77
13.71
1976
0 33
0.50
0.29
1.10
15.22
57.92
1.27
0.34
0.36
0.52
0. 13
0. 1 ]
40.47
1977
0.40
0.44
0.70
0.35
1U. 40
76.44
0.92
15.07
0.65
0.46
0.52
0.25
0.31
tu
1970
0.45
0.20
0.32
0.24
0.54
0.40
0.44
0.46
0.55
24.90
0.55
27.95
0.53
1.30
1.07
4.32
I
4^
1979
0.55
0.29
0.33
0.50
1.05
16.26
1.04
46.12
0.0 1
10.00
24.26
3.82
1900
0.50
0.46
0.42
0.75
0.16
0.24
0.34
0.33
0.33
0.25
31.66
4.00
2.57
44.96
0.72
35.68
0.09
0. 13
0.20■
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s-aTABLE Bl               HISTORIC STREAMFLOW SEQUENCE FOR AWASH RIVER R MBLKA KUNTURE IN MILLION CUBIC METRES DRAINAGE AREA-444O Ka2
JAN
FEB
MAR
APRIL
MAY
JUNE
JULY
AUG
SEPT
OCT
NOV
DEI
1963
2.67
2. IK
1 .31
12.10
34.49
22.43
109.09
375.84
204.31
18.36
6.56
5.96
1464
4.20
1.74
2.40
5.50
4.15
19.62
147.04
239.11
276.42
59.01
X
X
1965
X
X
X
X
X
X
X
X
X
X
X
X
1966
2.93
16.9 1
4.35
15.00
2.42
17.92
150.42
454.97
303.22
26.79
7.D7
4.30
1967
2.02
3.35
1.05
16.44
31.59
17.97
153.69
364.26
109.40
70.03
44.46
9.52
1960
3.15
11.72
5.94
50.33
10.02
22.01
179.06
242.60
156.31
41.47
7.50
7.58
1969
11.01
11.12
23.10
12.60
19.67
40.71
240.37
493.59
259.00
24.55
16.36
8.99
1 970
2.69
9.31
23.30
10.65
2.09
12.91
302.37
490.74
276.53
05.01
10.12
6.01
1971
6.22
2.90
1.60
7.46
10.93
95.94
309.33
520.01
348.92
43.67
9.40
13.04
1972
5.00
12.33
9.53
13.30
12.77
0.77
181.69
234.92
68.32
12.02
5.36
3.42
1973
6.60
1.60
0.69
0.32
4.60
13.57
120.04
380.30
286.31
53.33
9.65
6.10
1974
6.23
2.52
9.15
7.92
3.67
9.00
166.50
410.04
167.95
39.13
0.00
3.91
1975
3.64
2.50
1 .41
5.44
1.09
1.04
309.27
343.52
445.58
54.51
7.41
3.76
1976
2.79
1.22
4.28
2.03
0.30
10.04
119.37
3 16.06
132.11
105.00
7.36
3.41
1977
9.35
4.30
X
4.00
5.42
10.75
164.60
155.00
154.75
05.43
116.57
8.66
1970
4.63
6.95
6.43
5.23
4.64
21.32
159.13
350.49
170.76
36.39
0.36
5.75
1979
6.19
7.60
9.65
7.66
11.22
13.95
139.03
257.53
98.30
23.73
9.02
5.29
1 q30
2.56
2.07
5.22
3.20
2.07
16.73
200.02
371.06
129.69
16.40
4.17
2.20
NOTE: X Mistin') ditaTAM E r<J
URA1NAGE AREA-489 Mm2
HISTORIC STREAMFLOW SEQUENCE FOR HUGER RIVER AT CHANCHO IN MILLION CUBIC METRES
.IAN
FEB
MAR
ABRIL
MAY
JUNE
JULY
AUG
SEPT
OCT
NOV
DEC
1962
0.62
0.40
0.53
0.44
0.76
1.26
0.60
37.3)
51.02
11.02
2.24
1.38
196 3
0.D4
0.72
0.50
1.13
1.70
1 .61
66.37
91.70
35.50
3.37
1.00
0.80
196 4
0.47
0.30
0.27
0.25
0.22
1.53
30.10
50.57
50.39
11.14
2.00
1.42
1965
0.42
0.19
0.16
0.28
0.17
0.36
7.67
25.91
16.56
6.89
1.00
0.49
1966
0.20
0.32
0.23
0.57
0.19
1.07
22.50
90.20
36.21
10.73
0.95
0.48
1967
0. 19
0.29
0.31
0.32
1 .50
0.68
25.43
115.16
55.09
21.49
9.10
5.62
I960
4.50
4.0«
1.B6
4.63
2.(14
2.26
25.80
51.91
33.05
6.68
1.54
0.7B
1969
0.75
0.91
2.21
0.99
1.33
4.48
42.00
X
X
X
1.24
0.6)
1970
0.56
0.56
1.70
1.00
0.44
0.61
9.42
X
35.35
5.62
1.24
0.78
1971
0.55
0. Ji
0.42
0.65
0.69
1.02
38.11
79.73
33.73
6.12
1 .59
0.85
1972
0.47
0.52
0.60
0.71
0.67
0.7(1
55.38
117.05
26.36
2.40
0.68
0.45
1 973
0. 16
0.16
0.17
0.10
0.31
1.63
36.77
135.5)
06.02
12.on
1.26
0.59
1974
0.34
0.24
0.36
0.50
0.29
1.50
67.09
90.36
42.22
4.74
0.90
0.37
1 975
0.2 1
0.16
0.17
0.50
0.2 1
2.65
94.93
126.20
69.61
7.72
1.09
0.51
1976
0.40
0.20
0.29
0.36
0.62
1.55
72.54
80.92
38.33
2.41
1.07
0.51
1 977
0.94
4.96
0.20
0.32
0.49
3.10
125.08
141.37
79.56
43.93
35.69
12.79
1970
5.28
4.04
4.69
3.08
3.94
3.72
42.64
72.48
66.07
16.56
1.55
0.99
1979
1.01
0.0 1
0.47
0.57
0.92
1 . 16
H4.65
X
60.34
6.33
1.18
0.77
1900
X
X
X
X
X
X
X
X
X
X
X
X
NOTE: X - Missir.3 daf aTABLE 82 : Monthly Total Rainfall in mm
Hy<Jrolo3ic il Period: 1973-1982
STATION: Addie Ababa Observatory
JAN
FEB
HAk APRI
L
MAY
E
JOLY
AUG       SEPT
OCT
NOV
HEC
1973
1974
1975
1976
1977
1978
1979 1900 1981 1982
0.3
1.6
2.2
33.6
138.8
.0
267.7
345.5      269.0
50.3
0.0
52.5
0.0
31 .9
21 .7
0.9
60.3
94.8
65.9
00.3
84.9
114.2
53.5
113.3
.5
264.9
330.0      329.2
3.5
0.0
0.0
0.0
2.7
□ 4.4
.5
271.5
183.6       1U2.0
17.0
0.0
0.0
19. 1
61.4
44.0
.7
101.2
277.7       145.5
3.0
62.1
13.2
55.7
40.0
68.0
146.0
30.8
103.2
.6
255.3
280.6       133.6
272.3
1.2
0.0
2.1
63.3
10.1)
.7
200.1
361.3      111.0
39.1
0.0
3.4
127.9
19. 1
73.6
1.1
316.1
204.5       225. 1
0.0
0.0
16.2
aa. a
36.6
45.3
00.5
02.9
>.2
385.1
297.4       111.9
51.5
0.0
0.0
0.0
75.5
176.0
3.9
1.1
266.5
320.9       102.1
12.6
0.0
4.8
40.7
00.9
57.0
103.7
115.9
1.9
259.3
257.9       109.1
64.4
4 1.2
11 .9
CO
no:
X^Nissing data
I
00
I
■TABIE 02 : Monthly Total Rainfall in mm.
Hydrological Period: 1962-1979
STAY KiN: Lheno
JAN
FEB
MAR
APRIL
MAY
•
JULY
AUG
SLPT
OCT
NOV
HEC
1 962
X
X
X
X
X
0
332.0
173.0
127.7
1 963
X
4 .3
10.2
12.5
07.1
X
54.0
4.9
1
270.3
477.2
443.0
0.0
1964
13.(1
16.3
46.0
14.0
04.0
44.2
14.2
5
330.2
246.0
126.7
16.6
0.0
1965
7.9
0.0
73.7
56.0
0.0
11.3
0
202.7
520.6
22.3
17.9
41.5
0.0
1 966
P.7
63.6
14.0
35.0
0.0
0
391.9
574.0
135.5
0.0
1 96 7
0.0
0.0
57.3
0.0
00.2
0.0
39.2
5
0.0
0.0
93.0
46.7
60.3
0.0
I960
0.0
51.0
14.6
155.6
60.0
0
354.3
214.2
95.6
12.1
21.9
1969
54.3
93.7
0.0
131.0
151.4
64.3
7
320.6
351.1
29.5
1.0
5.1
1970
25.6
75.5
52.5
0.0
42.0
0.0
0
295.3
227.0
100.0
10.0
2.1
1 971
6.4
0.0
79.1
41 .7
70.7
2.6
2
270.2
312.9
73.9
7.0
5.1
31.3
1972
4.7
17.3
29.6
95.0
44.9
1
107.2
169.2
79.2
3.0
0.0
3.2
197 3
1.3
0.0
0.0
20.2
22.7
6
202.5
323.6
94.9
23.5
1 .1
12.4
J 974
6.7
15.3
51.5
5.7
54.1
1
324.2
163.9
02.5
2.2
X
X
1975
0.5
15.7
27.7
97.6
37.5
9
304.6
103.7
123.1
5.7
0.0
11 .7
1 976
7.6
0.0
10.4
69.3
76.2
9
265. 1
293.3
74.5
2.6
34.7
4.2
1977
52.5
34.4
19.9
46.6
61.1
0
303.6
250.0
45.3
110.0
13.7
0.0
1970
0.0
60.0
45.5
47.4
29.0
9
207.9
314.0
131.4
44.7
0.0
0.0
1979
92.2
14.4
H4.7
24.4
3.2
6
250.3
207.7
79.4
15.1
0.0
0.0
NO:      X»Mi 55 ing dataTABLE 82 : Monthly Total Rainfall in mu
Hylrol O'jic il Period: 1962- 1979
JAN          FEB          MAR      APR II
STATION: Sendafa
JUNE JULY AUG SEPT OCT NOU
1962
1963
1964
1965
1966
1 967
1960
1969
1970
1971
1972
1973
1974
1977
1978
1979
XXXX
26.0 79.0 7.0 141.0 31
X 10.5 196.6 205.0
.0 79.7 383.7 430.0
8.4            8.3          37.7         79.3          39 .5 25.3            0.0          10.1          31.3            7 . 4
0.0        141.8          25.6       140.3          96 . 0
0.0            4.0          82.0       155.1        112 .3
0.0          49.1            0.0           0.0          (1 .6
60.7          69.8         9.3.4         74.1            6 .6
00.4          39.1          71.4        57. 1          13 .9
3.7          10.2        169.1       100.6        272 .2
16.0        205.6          320.3
114.9 227.1 396.9
171 .9 293.5 522.4
33.2       2d(l. 6         176.6
04.7        443.7          113.2
117.1        279.3         27 4.2      134.4            37.4              0.0
177.4 34.0 1.0
80.9             0.1              1.3
05.4           43.9           32.1
71.8           19.7              0.0
60.5           20.0            45.2
](t6.6 10.1 0.0
09.6             3.1              6.0
48.3        319.9          666.3     208.1               9.3              0.0
405.8 354.1 66 4.9 260.4 43.2 8.7
33. 1             0.0          55.0       107.9         94
0       162.4        279.0          333.2
0.0            0.0            0.0         13.0         63 . s
62.3        217.1          465.6
0.0            0.0          87.0           0.5         93
.3        123.8        266.2          210.7      116.3               0.0                X
73.2             1.0            12.0
175.8 0.0 0.0
08.9          21.4          22.0         42.4          73 .4
145.1        390.9          359.2     262.1          165.1             10.0
0.5          86.5          49.1         33.8         46 133.7            8.6          02.3         56.2         01
4       155.6        264.6          289.0      109.7            80.2              0.0
. 1 111.3 429.4 256.9 132.8 13.5 0.0
8EI
24.0
20.0
36.3
0.8
0.0
0.0
0.0
0.0
0.0
22.0
12.0
3.0
X
0.0 ® 0.0
X
NB:      X = M i n « i ng data
0T-TAB! 1. B2 5 Monthly Total Rainfall in
Hydrological Period: 1972-1979
STATION: Ochre Perhan
JAN
run
MAK
APRIL
HAY
JUNE
JULY
AUG
SLPT
OCT
NUM
HEC
1972
X
19.0
33.3
57.7
11.0
X
219.7
150.6
H2.1
0.0
0.0
0.0
1973
6.1
0.0
0.0
32.3
79. 1
27.6
394.0
365.5
116.1
19.9
1974
0.0
4.9
00.3
0.0
0.0
15.7
39.0
149.0
299.5
X
X
X
X
1975
0.0
11.1
97.9
9.5
0.0
X
102.5
194.0
J20.7
102.5
0.0
0.0
0.0
1976
0.0
0.0
95.0
X
X
73. 1
212.1
245.7
19.0
13.5
15.0
5.5
1977
30.2
12.3
29.0
X
X
X
1111.3
336.8
36.5
107.4
X
0.0
1970
0.0
25.2
36.6
17.3
31.1
41.0
172.3
200.4
124.1
32.7
0.6
0.0
1979
01.1
7.4
66.0
71.0
69.7
50.2
J55.7
131.9
102.5
X
0.0
6.5
NR:
X=Hissing data
IT-TABLE B2 : Monthly Total Rainfall in ox
Hydrological Period: I960 J979
STATION: Mendida
JAN
FEB
MAX
APRIL
HAY
JUNE JULY AUG SEPT OCT NOV PEC
I960
1961
X
X
1962
1972
X
X
50.2
23.0
30.7
113.7
0.0
X
0.0
X
59.2
X
75.7
0.0
40.5
86.6
369.0
465.2
70.5
X
310.1
316.2
131.0
91.3
X
X
0.0
X
X
X
X
X
1974
1975
35.0
X
271.3
200.9
236.6
148.0
90.3
36.2
X
X
56.9
X
X
X
X
0.0
26.2
0.0
63.9
01.0
0.0
31.0
120.4 24.2
185.5
29.6
359.9
257.9
X
210.4
44.0
65.0
X
0.0
X
X
X
0.0
1976
1977
3.0
97.7
40.0
12.7
X
25.1
82.6
X
X
21.5
65.0
66.4
330.0 21)9.1
252.5
401.7
62.4
81.3
16.0
43.4
21.0
X
0.0
0.0
1 978
1 979
0.0
97.0
64.0
4.5
10.7
51.0
0.0
47.0
X
44.6
X
260.9
217.6
55.2
97.0
40.2
X
X
X
X
0.0
X
25.8
X
HH:
X-Mivilri'i dataHy > lroIogic11 Period: 1969-1979
JAN           FEB          MAR          APRIL        MAY        JONE         JULY            AUG          SEPT            0( T             NOV            HEC
1 96 9
63.2
X
X
X
11.4
X
533.5
434.4
X
0.5
4.0
0.0
1970
40.0
X
X
X
4.0
20.0
370.5
534.7
X
7.3
0.0
4.0
1972
X
X
X
X
X
166.2
146.0
X
97.7
X
X
X
1 973
X
X
0.0
69.0
X
54.0
332.1
460.5
157.9
50.0
11.5
30.3
1 974
0.0
14.9
109.0
0.0
157.7
197. 1
439. 1
305.4
144.5
6.6
0.0
0.0
1975
0.6
43.1
40.0
□ 7.0
91.0
109.0
309.0
357.7
226.5
X
0.0
X
1 976
0.0
X
15.0
19. 1
68.2
59. J
541.0
390.6
1 47.6
0.0
49. 1
3.7
1 977
3 .3.4
37.9
34.1
27.1
50.0
03.0
599.9
319. 1
X
1 970
221.9
0.0
0.0
X
56.0
29.0
40.2
1.1
109.7
X
X
163.7
63.8
1 979
79.9
23.4
66.6
X
X
134.2
69.2
361 .:)
15.9
X
X
X
X
X
X = M i f»s i ng d it aTAD1.E 1<2 : Monthly Total Rainfall in me
Hydrological Period: 1972-1979
STATION: Chancho
JAN           FEB          MAR          APRIL        MAY         JUNE         JULY            AUG         SEPT            OCT           NUM            [(EC
1972
X
X
X
X
X
103.6
264.4
191.6
03.9
X
32.2
31.7
1973
0.0
0.0
4.0
16.0
52.3
180.3
290.6
320.5
107.1
0.7
0.5
0.7
197 4
0.0
19.0
91.3
9.5
70.2
133.6
190.0
216.0
00.6
9.0
0.0
4.2
1975
15.7
22.0
35.4
07.9
113.7
169.9
351.7
244.5
50.5
0.0
1 .0
27.5
1976
7.5
39.9
64.1
93.9
23.1
245.4
290. 1
X
X
X
X
X
1977
51.1
21.7
109.2
50.9
31.4
215.4
377.4
270.5
95.9
165.7
12.4
X
197(1
X
X
X
45.4
11.5
X
356.0
391.0
200.5
9.3
X
20.2
1979
90.0
19.3
60.7
X
119.7
123.6
270.0
136.3
X
X
X
X
X = Mtasing datiTAPLE P2 : Monthly Total Rainfall in mm.
Hydrological Period: 1974-1982
STATION: Sululta
JAN
FEP
MAR
APRIL
MAY
JUNE
JULY
AUG
SEPT
01 T
NOV
IIF.C
1974
X
X
X
X
97.4
134.1
271.3
231.2
107.0
6.0
0.0
0.0
1 975
0.0
2.5
27.0
□ 7.6
70.6
128.9
361.1
295.6
148.0
10.2
0.0
0.0
1976
38.0
17.0
52.9
80.9
117.4
182.7
448.2
310.5
59.6
18.0
57.3
11.5
1 977
109.5
23.5
37.4
61.1
70.4
241 .9
378.0
290.8
130.1
174.7
0.0
0.7
1978
2.0
36.4
40.5
16.7
17.3
174.0
298.1
251.2
133.1
41 .0
0.4
0.2
1979
144.9
27.3
25.3
15.2
3.3
65.9
302.4
267.1
105.0
7.1
0.0
2.5
1980
10.1
31.8
70.0
33.8
14.6
79. 1
353.0
522.3
228.5
7.7
X
0.0
1901
0.0
0.0
122.8
68.7
183.4
57.5
395.5
418.5
77.1
2.0
0.0
1.3
1982
35.5
36.9
62.6
79.7
109.9
92.2
277.1
269.6
93.3
28.5
52.7
X
HP:
X'Hiffirig data
tnTABLE M2 : Honthly Tuld) Kain/al 1 in mm
Hydrological Period: 1970, 1974
STATION: Mehle-Ttige
JAN
FEB
MAM
APRIL
MAI
JUNE
JULY
AUG
SEPT
OCT
NUM
HEC
1970
X
X
X
X
X
X
220.0
X
X
X
X
X
1974
X
X
X
X
X
X
X
101 . 1
147.0
X
X
X
Monthly Total Maintal 1 in mm.
STATION: Muketuri
Hydrological Peilod: 1970
1971        1974
IAN           FEB           MAk        APR 11         MAY        JUNE         JULY           AUG        SEPT           OCT           NUM           MEI
1970
1971
1974
X
16.5
X
X
10.4
X
9.0
X
61.1
X
97.2
X
50.5
X
276.3
X
X
404.0
134.3
X
5.7
X
24.9
12.4
77.1
X
X
X
X
X
X
160.7
155.6
X
X
X
Monthly Totjl Rainfall in mm.
IlyJrol o'jiljI Period: 1925 1979
STATION: Meneba
JAN
LEK
MAk
APk 11.
MAY
JUNE
JULY
AUG
SLPT
OCT
NUM
HEC
1975
X
X
X
X
X
140.7
290. (1
261.4
226.0
65.0
0.0
0.0
19 '6
0.0
0.6
10.6
X
X
X
353.3
.166.5
50.0
120.6
0.0
32.3
1977
90.7
13.6
41.. 0
56.0
39.0
X
X
X
57.1
76.1
X
X
1 97U
X
47.7
19.3
40.9
0.0
91.9
X
101.2
07. 1
0.0
2.5
9.1
- - — ■ — - - - — - . — - - - —
Nl<:       X-Mi eci ng data
1 979
66.7
57. Ic
32.9
411.7
9) . 4
X
43.3
122.3
X
X
X
30.0
________B-17
There are 11 rainfall stations and 4 streamflow gauging 
stations near the Aleltu project area. From Plates B-l and 
B-2, and Tables B. 1 and B.2, it can be observed that
- rainfall stations do not exist within the main Aleltu Basin 
area
-    rainfall data are mostly incomplete with poor overlap of
recording periods, with the exception of the Addis Ababa, 
Sendafa and Sheno stations
-    three streamflow stations are located at the eastern and 
western side of the Aleltu Basin and a fourth station is
located just south of Addis Ababa. Although some data are
missing, the records of these stations are generally 
complete, show a good overlap and extend over a period of
about 20 years.
-    three new streamflow stations were installed during July
1983 for the purpose of the Aleltu project studies; these
stations are located on three of the main rivers in the
project development area. Overlapping data with other
stations, however, were not available in time for
incorporation in this report.
B2.2 - Streamflow Data Analysis
The        discharge        records        of        the        following        gauging        stations        were analyzed
-    Chacha River at Chacha
-    Beressa River at Debre Berhan
-   Awash River at Melka Konture
-   Muger River at Chancho.J
B-18
The records of these stations are shown in Table B.l.
Beressa Station
The record of the Beressa station is complete and contains 19 years of monthly historic streamflow data from 1962 to 1980.
Chacna Station
The record of the Chacna station contains flow measurements from 1962 to 1980 with some months missing during 1968, 1969 and 1980. Estimation of flows during these months was carried out using the following relationships.
Sum A - Sum M
Sum SD
where
F ,p = characteristic factor for wet or dry period 
n
"p" of year "n"
Sum A = sum of available flow in period "p"
Sum M = sum of the mean monthly flows in 
period "p"
Sum SD = sum of the standard deviations in period "p" and
Flow = M + m
F x SD
n,p              mB-19
where
Flow      =      estimated      flow      in      month      "m,"      period      "p"      of      year      "n" M   = mean of recorded flows in month "m"
m
SDm = standard deviation of recorded flows in month "m"
Muger Station
The       record       of       the       Muger       station       contains       18       years       of       obser vations with some months missing during 1969, 1970 and
1979.              Flows      in      these      months      were      estimated      using      the      same technique as for the Chacha station. For the entire year
1980,      however, no recordings are available. To extend the data, corelations with the other discharge records were carried out. The results in Table B.3 indicate that none
of these correlations provide a reliable basis for extend
ing data. However, because of lack of better data and in view of the preliminary nature of the analysis, it was
decided to accept the Muger versus Beressa relationship in order to extend the Muger discharge record.
Awash Station
The record of the Awash station contains 17 years of data with some months missing in 1964 and 1977. These data were filled in using the same technique as for the Chacha
station. However, the entire records for 1962 and 1965 are missing. Corelations witn the Beressa, Muger and Chacha stations were carried out as snown in Table B.3. The corelation with the Beressa River was selected as the most suitable for data extension and the missing Awash data were estimated on this basis.
The complete 19-yr historic and extended streamflow sequences of the four gauging stations are shown in Table B.4.*
B-20
TABLE B.3
DISCHARGE RECORD CORELATIONS
Corelations
Muger versus Chacha
Number of Data Points
14
Corelation Coefficient
2
(r )
-0.081
Standard Error       of Sample
(SE)
5.37
Standard Error       of the Mean (SE/ «^n)
1.44
Muger versus
16
0.222
7.47
1.87
Beressa
Muger versus
11
-0.055
18.86
5.69
Awash
Beressa
15
0.502
23.63
6.10
versus Awash
Chacha versus                 12 Awash
0.510
82.96
23.95TAKI    L    B4    :    HISTORIC    STREAKF1    (IU    SEQUENCE    FOR    BERESSA    RIMER    AT    DEBRE    H1RHAH    IN    MILLION    CUBIC    METRES URA INAGE AREA 21 1 |t»2
a
IAN              FEB            MAR           APRIL          MAY         JUNE         JULY
AUG         SEPT           OCT           NOV           BEL         :              ANNUAL
TOTAL       MEAN
1 962               0.32            0.27            0.50             0.55            0.60            0.91            22.79        45.63          19.36            1.73            1.30          0.75
1 96 3 0.43 0.20 0.35 1.15 2.10 1.02 27.36
196 4 0.29 0.10 0.22 0.71 0.51 0.65 42.58
1 965               0.63             0.35            0.04            2.13            0.91             1.12              1.13
1966               0. 47            0.60            0 62             1.12            0.06            1.69              5.63
1 967              0.6 1            0.52            1 .04           1 . 42          2.117           1.47            29.92
1960                1.00             1.4)             1.15            1.32           1 . 44           1.80            60.92
1 969 2.90 0.39 1 . UO I . 30 1.3.1 0.42 34.53
1970                0.41             0.27            0.67            0.37            0.64            0.54            34.05
1 97 1              0.29            0.15            0.20            0.40            0.70            5.53            22.23
197 2               0.38             0.40            0.27            0.36            0.34            0.90              6.40
94.71            7.09
197 J
0. u             0.37            0.24            0.3.3            0.52            0.51            20.66
197 4               0.39             0.36            0.40            0.53            0.40            0.57            42.17
1 975               0.3.1            0.25            0.33            0.50            0.29            1.10            15.22
1 97 6              0.13            0.11             0.40            0.44            0.78            0.35            18.40
1 97 7              0.46           0 . >1            0.20            0.24            0.40            0.46            24.90
1 970               0.45          0.32            0.54            0.44            0.55            0.55            16.26
1 97 9              0.55            0.29            0.33            0.50             1.05            1.04            24.26
1900                0.16            0.24            0.34             0.33            0.33            0.25              4.80
65.69            0.00            1.12            1.12          0.09
49.04          12.28            0.99            0.35          0.23
24.35            0.10            1.20           2.02          2.90
58.36 22.57 0.07 0.60 0.63 50.06 6.24 7.21 2.07 1.32 57.83 14.40 3.40 3.14 2.08
109.06              3.71            0.53            0.30          0.42 63.58            7.57            0.93            0.25          0.34
110.01              9.24            0.41            0.36          0.48
48.06          12.15            0.86            0.43          0.34
60.22          19.97            0.60            0.46          0.36
52.77          13.71            1.27            0.52          0.52
57.92          40.47            0.92            0.65          0.25 76.44          15.07            0.53            1.07          0.46 27.95            1.30           4. 12           0.03          0.42 46.12          18.00            3.02            0.50            0.75 31.66            2.57            0.72            0.09          0.13 44.96          35.68            5.39            0.52            0.20
109.51 9.13
10U.U3 9.07
46.26            3.86
94.04            7.04
105.55 8.00
150.85 12.57
156.92          13.00
109.62            9.14
150.DO          12.57
72.89            6.07
104.47 8.71
1)3.51            9.46
110.39            9.87
114.18            9.52
62.03            5.17
80.30            7.36
63.19            5.27
93.20            7.77
U3
I
bJ
MEAN 0.56 0. 39 0.56 0.75 0.08 1.11 24.02
I-LOU
56.91          14.24            1.94            0.92            0.75       :
103.02
0.58
STU.
0.60             0.30            0.42            0.52            0.66            1.16           1 4.82        22.68          10.33            1.94            0.86            0.80
OEM
C . 01 1.079 0.775 0.753 0.685 0.755 1.052 0.617
VAR
X 0.54 0.38 0.54 0.73 0.85 1.07 23.31
0 ISTR I8UT ION
0.390 0.726 1.000 0.937 1.071
55.25 13.82 1 .08 0.09 0.73
S 29.76 2.48
:            0.289          0.289
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lilf A INAGE AKEA-418 Kiu2TAU1 E U4                 HISTORIC ANU EXTENUEU STREAMFLOW SEQUENCE FOR AWASH RIMER V MELKA KUNTURE IN MILLION CUBIC METRES
hRAJNAGE AREA=444O Cm2
JAN            FEU           MAR          APRIL          NAY         JUNE          JULY           AUG         SEPT            OCT           NOM           UEC         •               ANNUAL
TOTAL       MEAN
1962                3.60A         4.50A         6.30A         6.40A         6.10A                        19.00A187.50A332.20A269.75A     40.30A        15.20A           6.00A
•
•
1 963              2.67            2.10            1.31          12.18        34.49          22.43       189.09       375.84          204.31           18.38            6.56            5.96 196 4              4.28           1 .74           2.40            5.50            4.15        19.62       147.04        239.11          276.42          59.01              9.65A         5.65A
•
•
•
896.85v 74.74e
875.40             72.95
•           774.57v           64.55c
) 965
4.90A     14.30A       12.30A         29.00A     10.90A     23.20A 81.00A246.05A155.70A
32.80A       23.50A         14.30A
•
• 1007.12 U3.93
647.95e           54.00e
1 966              2.93          16.93            4.35        15.00              2.42        17.92       J50.42        454.97          303.22          26.79            7.87            4.30
1 96 7             2.02            3.35            1.05         16.44          31.59        17.97       153.69       364.26           189.40          70.03          44.46            9.52
I960               3.15         11.72            5.94          50.33        10.02              22.0)    179.06        242.60          156.31          41.47            7.58            7.58
I 96 9           11.01           1112          23.18          12.60        19.67             48.71    240.37        493.59          259.00          24.55          16.36            8.99
1970              2.69           9.31          23.30          10.65            2.09           12.91    302.37        490.74          276.53          85.01          10.12            6.01
) 971              6.22            2.90            1 .68           7.46          16.93            95.94   368.33          520.01        340.93          43.67            9.40         13.D4
1972              5.0U         12.33            9.53          13.30          12.77              8.77   181.60        234.92             88.32          12.02            5.36            3.42
1 973 6.68 1.60 0.69 0.32 4.60 13.57 120.04 300.30 206.31 53.33 9.65 6.10
197 4 6.23 2.52 9. 15 7,92 3.67 9.06 166.50 418.04 167.95 39.13 0.08 3.91
1975 3.6 4 2.50 1.41 5.44 1.09 1.84 309.27 3-43.52 445.58 54.51 7.41 3.76
•
•
•
904.5U            75.36
•
•
•
•
•
•           737.77             61.48
1169.15 97.43
1339.73      103.31
•           1457.30      121.45
•
• 507.50 48.96
883.19             73.60
•
•
•
•
••
842.9(1 70.25
1180.77 98.40
I
K)
UJ
1976
2.79
1.22
4.2(1
2.63
6.38
18.04
119.37
336.86
132.11
105.80
7.36
3.41
742.45
61.87
J 977
0 . 15
4. 10
17.75A
4.00
5.42
18.75
164.60
155.08
154.75
05.43
116.57
0.66
•■
743.66V
61.97e
1 970
4.63
6.95
6.43
5.23
4.64
21.33
159.13
350.49
178.76
36.39
8.36.
5.75
••
780.09
65.67
1 979
6.19
7.60
9.65
7.66
1 1.22
13.95
139.83
257.53
90.30
23.73
9.02
5.29
••
••
509.97
49.16
1 900
2.56
2.07
5.22
3.20
2.07
16.73
208.02
371.06
129.69
16.46
4.17
2.20
765.15
63.76
MEAN
4.72
6.31
7.72
11.34
10.26
22.24
108.85
348.17
2)6.91
45.73
17.20
6.56
••
686.0)
73.83
I LOU
STU.
3.31
4.09
6.99
11.45
9.62
20.04
74.69
101.22
92.02
25.83
25.72
3.30
••
231.97
19.33
OEM .
( . 0!
0.489
0.775
0.905
1.010
0.938
0.901
0.395
0.291
0.428
0.565
1.496
0.503
••
0.262 0
.262
MAE
X
0.53
0.7)
0.87
1.28
1.16
2.5)
21.31
39.30
24.40
5. 16
1.94
0.74
••
100.00 X
HISTR(BUT ION
note: a L 3 ti■aIedTABLE U4               HISTORIC ANU EXTLNDEU STREAMFLOW SEQUENCE FOE HUGER RIVER AT CHANCHO IN HILLION CUBIC HETRES I'RAINAGE AREA»489 Kh2
JAN          FEU          HAH       APRIL         HAY
JULY AUG 6EFT OCT NOV
DEL :
ANNUAL
TOTAL MEAN
1962           0.62          0. 40         0.53            0.44         0.76
1963           0.04          0.72          0.50            1.13         1.70
1964           0.47          0.30          0.27            0.25         0.22
1965           0.42          0.19          0.16            0.30         0.17
1966           0.20          0.32          0.23            0.57         0.19
1967           0.39          0.39          0.31            0.32         I .58
1960           4.50          4.00            1.06          4.63         2.04
1969            0.75          0.91          3.21            0.99         1.33
1970           0.56          0.56            1.70          1.00         0.44
1 971           0.55          0.31          0.42            0.65         0.69
1972           0.47          0.53            0.60          0.71         0.67 197 3          0.36          0.16          0.17            0.10         0.31 197 4           0.34          0.34            0.36          0.50         0.29 1975           0.2 1         0.16            0.17          0.50         0.23 1976           0.40          0.20            0.29          0.36         0.62 1977            0.94           4.96           0. !0          0.33         0.49
1970           5.28          4.04            4.69          3.08         3.94 1 979           1 .01         0.0 1           0.47          0.57         0.92
1900           0.45A        0.43A          0.29A       0.46A       0.55 A       1.30 A             35.70A 75.58A   41.35A            7.83A        0.64A
1.26             6.60       37.31       51 .02        11.02             2.24
1 .61          66.37       91.70       35.50             3.37           1 .00
1.53           30.10       50.57       50.39         11.14             2.00
0.36             7.67       25.91        16.56             6.69           1 .00
1.07           23.50       90.20       36.21         10.73             0.95
0.60           25.43     115.10       55.09         21.49             9.10 2.26           25.60       51.91       33.05             6.60           1.54
4.48           42.08       02.35A     45.25A        11.90A         1.24
0.61             9.42       53.95A    35.35             5.62           1 .24
1.03           30.11       79.73       33.73             6.12           1.59
0.70            55.38     117.05       26.36             2.40           0.68
1 .63          36.77     135.51       06.02         13.00             1.26 1.50           67.09       90.36       42.22             4.74           0.90 2.65           94.93     126.20       69.61             7.72           1.09 1.55           72.54       08.92       38.33             2.41           1.07 3.10         125.00    141 . 37      79.56         43.93          35.69 3.73           42.64       72.46       66.07         16.56             1.55 1.16           H4.65   120..18A     60..14            6.3.)          1 . 10
1.38
0.08
1.43
0.49
0.48
5.62
0.78
0.61
0.78
0.05
0.45
0.59
0.37
0.51
0.51
12.79
0.99
0.77
0.55A
115.511 9.63
205.22 17.1 1
148.66 12.39
60.10            5.02
163.65 13.64
225.40 19.62
139.93         11.66
194.lOe 16.18m
111.31            9.28
164.5/ 13.71
206.07              17.17                                         1
W
275.04 22.92
200.91 17.41
J04.00          25.33
207.20          17.27
440.51          37.36
225.84      111.62
27*2.6 le       23.22m 165.13e   13.76m
to
lU
MEAN
Fl OW
STU.
BEV.
C. 01
VAR
0.99           1.03          0.82           0.93          0.94           1.74        46.89        86.67         47.47         10.47           3.48           1.62
1 . 40         1.51          J . 12         1.21           0.99           1.00        31.54        33.31         18.20           9.42           8.02           2.94
•
•
203.06          16.92
U5.29           7.11
1.4)5         1.459         1.368          1.292        1 .04(1       0.620         0.673        0.304         0.383         0.900         2.306       1.813         •           0.420         0.420
X               0.49
U 1STfc 1 BIJT ]()N
0.51           0.40           0.46           0.46           0.86        23.09         42.68         23.38           5.16           1.71           0.60       •         100.00 Z
NOTE: A EstimatedB-25
B2.3 - Rainfall Data Analysis
Rainfall Isohyet Map
To estimate the long-term average annual rainfall on the subbasins of the Aleltu project, a rainfall isohyet map was prepared from the small-scale isohyet maps of the meteoro logical atlas of Ethiopia and the data in Table B.2. The
long-term mean annual rainfall was calculated for each rainfall station and plotted on a project area map. The
data from the rainfall stations were used to supplement the available isohyet contours and the isohyet map was redrawn specifically for the project area. Plate B-l shows the estimated rainfall isohyets over the project area.
Comparison of
Rainfall Stations
From Plate B-l, it is observed that rainfall stations are not available within the Aleltu project area, but there are a number of rainfall stations located around the project area. These stations are
-   Addis Ababa Observatory
-   Chancho
-   Debre Berhan
-   Debre Tsige
-   Deneba
-   Fiche
-   Mendida
-   Muke Turi
-   Sendafa
-   Sheno
-    Sululta.B-26
Generally, most of the data sets of these stations are
incomplete with single month and/or series of months or
years missing. The Debre Tsige, Deneba and Muke Turi
records, containing fewer than 6 years of data, were
omitted from the analysis. The remaining stations have
record lengths varying between 8 and 18 years but these do 
not all have overlapping time periods.
Annual,        seasonal        and        monthly        corelation        analyses        were carried        out        between        the        rainfall        stations.        The        results        of these       analyses       are       snown       in       Table       B.5.       The       incompleteness of      the      records      results      in      a      lack      of      overlapping      data.      For the     cases     where     an     overlap     of     more     than     2     years     was     avail able,      no      corelation      could      be      found      between      any      pair      of      the stations.          These          results          are          particularly          surprising          for the       Sendafa       and       Sheno       stations,       which       are       located       within 35     km     of     each     other     and     have     record     lengths     of     18     years, with       13       years       overlapping.       Apparently,       there       is       a       large spatial        variation        in        rainfall        in        the        Aleltu        project        area with       spot       rainfall       patterns       occurring       in       a       random       manner. This         situation         is         consistent         with         rainfall/storm         systems dominated by line squall and thunderstorms.
Monthly corelations were also carried out. From these, it was established that corelations appear to exist only for some of the dry months of most of the stations, which likely results from lack of rainfall during these months and these are therefore of little value.B-27
TABLE B.5
RAINFALL CORELATIONS
Station
Years of
Record
Results of Corelation Analysis
Annual
Seasonal
Sheno  Wet
(18 yr)
—
Sendafa  D
(18 yr)
Fiche                 10
Addis
Ababa
10
Sheno
(18 yr)
no over
lapping
data
n = 6
r 2 = 0.15
no over
lapping
data
n - 3
r 2 » -0.99
n = 5
r 2 = 0.18
n = 2
Sendafa
(18 yr)
no over
lapping
data
n = 3
r 2 = 0.75
no over
lapping
data
n » 2
n = 2
-
-
Mendida             8
——
Deb re
Berhan
8
-
-
Sululta 9
Chancho 8
-
-
no over                  —
-
lapping
data
She no
18
-
-
-
n    =    13
(dry)
r 2 = 0.24
Sendafa
(wet)
18
-
-
n = 14
r 2 = 0.13
-
Note: n
r2
= number of years of data = corelation coefficientB3        PRELIMINARY STREAMFLOW
SEQUENCE ANALYSIS
During the initial phases of the study, rainfall data were
not available and for tne purpose of the preliminary runs of
the layout optimization model, monthly inflow sequences of
the subbasins were calculated based on streamflow records
only. The derivation is described below.
B3.1 - Evaluation of
Discharge Stations
To establish the inflow sequences for each subbasin of the
Aleltu project, the use of one or more of the available
discharge records was required. The selection was based on 
the following evaluation.
The Awash station at Melka Konture has a drainage area which
is about 10 to 20 times larger than that of
basins       or       any       of       the       other       stations.       Also, farthest away from the Aleltu project area.
Konture station, therefore, appears to be least attractive
the Aleltu sub this station is
The Melka
for inflow sequence
generation.
The Beressa station at Debre Berhan has a drainage area of about half tne size of the Muger and Chacha basins. This station is located outside the Aleltu Basin and directly to the east of tne Chacha station, away from the project area. For these reasons, the Beressa station was not further consi dered .
From Plate B-l, it is shown that the annual mean rainfall in the basin varies from east to west. The Chacna station isB-29
located at the eastern end, just inside the Aleltu Basin, 
while the Muger station is located at the western end, also just inside the basin. Both stations have drainage areas comparable in size with the subbasins of the Aleltu project. Therefore, the Chacha and Muger stations appear to be the obvious choice for inflow sequence generation.
However, corelation of monthly flow data between the two stations is poor as shown in Table B. 3 and the use of these stations would not provide a reliable historical data basis.
When the long-term specific mean flows of the stations are compared, however, there appears to be a strong similarity between the specific runoff from these stations as shown in Table B.6.
Also, when the annual discharge records of the Chacha and Muger stations are examined probabilistically, it can be shown that there is a consistent relationship between the two records. This is shown on Plate B-3, Figure 1.
It is therefore concluded that, although there does not
appear to be a deterministic relationship between annual or monthly flows from these basins, long-term average flow con ditions appear to be consistent with drainage area and mean annual rainfall and a probabilistic corelation can be shown to exist. It was considered that, for the preliminary recon naissance analyses, the use of these discharge stations would be acceptable, but that all results would require confirma tion by more detailed hydrologic analyses, including a rainfall/runoff analysis.B-30
TABLE B.6
COMPARISON OF CHACHA AND MUGER STREAMFLOW PARAMETERS
Description
Unit
Chacha
Muger
Recorded annual runoff
Mm3
146.4
203.1
Drainage area
km2
418
489
Mean annual runoff
mm
350
415
Annual rainfall
mm
1 100
1 250
Runoff coefficient
mm/mm
0.32
0.33B-31
B3.2 - Generation of
Inflow Sequences
To account for the variation from east to west of the rain
fall pattern over the basin, preliminary inflow sequences for
the Aleltu subbasins were derived by calculating the dis
tances from the centroid of each subbasin to the Chacha
station as a ratio of the distance between the Chacha and
Muger       stations.       Monthly       flows       over       a       period       of       19       years       were then calculated by computer using the following
relationship.
r ,X x Flow Chacha. ,84-X x Flow Muger., Flo “sub ' “sub x [(84 DA Chacha > + ’“5V ’da MT'ger"1 1
where
Flow = monthly flow
DA = drainage area
X = distance from Chacha station to centroid of subbasin
84        = distance between Chacha and Muger (km)
sub = subbasin
Table       B.7       shows       the       distances       to       the       centroids       for       the       ten subbasins considered in the initial model runs.
B3.3 - Assessment of the
Regulation Potential
of Eacn Reservoir
To establish the relationship between tne degree of flow regulation and the reservoir volume required to maintain that regulation, a monthly reservoir balance was carried out byB-32
TABLE B.7
CENTROID DISTANCES OF SUBBASINS IN PRELIMINARY HYDROLOGY STUDY*
Subbasin
X-Distance**
(km)
Agat
58.0
Tinishu Aleltu
57.5
Tiliku Aleltu
51.5
Jida
37.0
Gomoro
30.0
Robi
19.0
Weserbi
62.0
Duber
57.5
Chacha
0.0
Jinjer
11.5
Muger
-      Lat      09°18*;      Long      38°44'
Distance:
Chacha to
 Muger = 84 km
* Locations: Chacna - Lat 90°32'; Long  39°28'
*’X-Distance is between centroids of subbasins and the Cham* gauging station. 
naB-33
computer analysis. In this analysis, a monthly accounting is
made of change in reservoir storage and spill volumes for the
monthly inflow volumes and for a given constant reservoir
outflow draft rate, according to the following water balance
equation.
Outflow = (Inflow)-(Evaporation)-(Spi11) + (Change in Storage)
Reservoir        evaporation        losses        were        considered        to        be        small        and were not taken into account in the initial model runs.
For each reservoir scheme, the analysis was repeated for
three or more different draft rates. The results were then 
plotted to determine the relationship between the degree of regulation (i.e., the ratio of draft rate to mean annual
inflow volume) and the corresponding storage volumes required to maintain that draft rate without reservoir failure. The reservoir volumes thus derived were used in the layout opti mization model. For comparison purposes, the required live storages at 100% regulation are shown in Table B.ll (see Section B.6).
B4 - FINAL STREAMFLOW
SEQUENCE ANALYSIS
To verify the apparent lack of satisfactory corelations
between individual rainfall records and streamflow records, 
the rainfall/runoff relationships in the Aleltu project area
were investigated. For this purpose, regression analyses of
tne Chacha streamflow record with the Addis Ababa, Sheno andB-34
Debre Berhan rainfall records were carried out. No 
satisfactory corelation between these records, either on an annual, seasonal or monthly basis, could be found.
Obviously, the derivation of reliable inflow sequences for
the subbasins of the Aleltu project cannot be based on the
use of rainfall/runoff regression. Therefore, other statis
tical methods were employed to derive synthetic flow sequences in the manner reported below.
B4.1 - Derivation of Synthetic
Flow Sequences
To make the best possible use of available rainfall and discharge data, synthetic flow sequences were derived from
the Chacha streamflow record, utilizing the 18-yr records of
the Sheno and Sendafa rainfall stations, the rainfall iso
hyets over tne Aleltu Basin and the rainfall/runoff relation ships at the Chacha and Muger stations. A probability
ranking analysis of rainfall and runoff was used to establish 
a means of developing a streamflow sequence with statistical variability typical of the known rainfall variability. The
stepwise methodology employed in the analyses was as
follows.
(a)        Using calculated mean annual rainfall from available rainfall stations, together with the available rainfall
map of Ethiopia, rainfall isohyets over the basin were determined.
(b)       From the isohyets, the mean annual rainfalls of the drainage basins subtending the Chacna and Muger stream flow stations were determined.B-35
(c)             Using       the       Sheno       and       Sendafa       rainfall       records,       average annual          dimensionless          probability          of          exceedance          curves were developed.
(d)      Utilizing the extended and actual discharge records of
the Chacha and Muger stations, the annual discharges were ranked by magnitude and the corresponding probabi lities of occurrence calculated.
(e)       Utilizing these probabilities, the corresponding annual rainfalls for the Chacha and Muger stations over the available period of record were calculated using the curves derived in Step (c).
(f)        The ranked rainfall/discharge relationship using data at Muger and Chacha was derived from the results of Steps (d) and (e).
(g)       The areas of the Aleltu project subbasins were calcu lated from the available topograpnic mapping.
(h)       Utilizing the statistics of the discharge record at
Chacha (i.e., monthly means, monthly standard deviation and monthly serial corelation coefficients) and the drainage area of the subbasins, a series of monthly discharge records for each subbasin, based on the Markov single-step generation method, using single-seeded ran dom numbers was developed. The annual and long-term mean annual runoffs of the generated series were then calculated.
(i)       From the rainfall isohyets, the expected mean annual rainfall at the centroid of each subbasin was determined and, from the rainfall/discharge relationship of
Step       (f),       the       expected       long-term       mean       annual       runoff       was estimated.B-36
(j)        The generated monthly discharge records were adjusted linearly by the ratio of the expected long-term mean annual runoff to the generated long-term mean annual runoff.
The foregoing steps are elaborated in the following 
paragraphs.
(a)       The rainfall isohyets of the Aleltu project area are
shown on Plate B-l.
(b)       The mean annual rainfall of the Chacha and Muger station areas were determined by drawing detailed rainfall isohyets over the drainage areas and calculating the contribution of the areas between the rainfall isohyets
to the mean rainfall. It was found that the mean annual rainfalls of the Cnacha and Muger station areas are
1,100 and 1,250 mm, respectively.
(c)       Because of their long and complete records, an analysis
of the Sheno and Sendafa rainfall records was carried 
out and the results were utilized to develop average annual dimensionless probability of exceedance curves. It was found that, by omitting the extremely large 1971 Sendafa rainfall, a reasonable statistical relationship 
was found between tnese stations. The 1971 rainfall
had the nignest recorded values in each month from March to September. Such rainfalls were not recorded at any 
of the other rainfall stations and a detailed review of these records is required for future analyses.
In the probability of exceedance curves, the recorded annual rainfalls were calculated as a ratio of the mean recorded value and were plotted against the probability of occurrence. Probabilities were calculated using the following formula.B-37
where
Pi = probability of the ith ranked value of the
series
i = rank of the value in the series
n = total number of values in the series
The two curves for Sheno and Sendafa were averaged and the results are shown on Plate B-3, Figure 2. It is
noted that the area below the curve represents the dimensionless annual rainfall volume expressed as a function of the mean annual rainfall.
(d)       The extended and historic discharge records of the Chacha and Muger are shown in Table B.4. The annual discharges were ranked and the corresponding probabili ties of occurrence were calculated, utilizing the above formula.
(e)        It is noted that the calculated probabilities of the
ranked Muger and Chacha discharges are based on a 19-yr record. To determine the correspondingly ranked annual rainfalls, the probability of exceedance rainfall curve was entered utilizing these probabilities (abscissa) and considering the calculated mean annual rainfalls at the Chacha and Muger gauging stations (ordinate).
(f)        A typical rainfall/runoff relationship for the Aleltu Basin was determined by plotting the ranked rainfall and discharge data calculated in Steps (d) and (e) above. This is shown on Plate B-3, Figure 3.B-36
(j) The generated monthly discharge records were adjusted linearly by the ratio of the expected long-term mean annual runoff to the generated long-term mean annual runoff.
The foregoing steps are elaborated in the following 
paragraphs.
(a)        The rainfall isonyets of the Aleltu project area are
shown on Plate B-l.
(b)       The mean annual rainfall of the Chacha and Muger station areas were determined by drawing detailed rainfall isohyets over the drainage areas and calculating the contribution of the areas between the rainfall isonyets
to the mean rainfall. It was found tnat the mean annual rainfalls of the Chacha and Muger station areas are
1,100 and 1,250 mm, respectively.
(c)        Because of tneir long and complete records, an analysis of the Sheno and Sendafa rainfall records was carried 
out and the results were utilized to develop average annual dimensionless probability of exceedance curves. It was found that, by omitting the extremely large 1971 Sendafa rainfall, a reasonable statistical relationship 
was found between these stations. The 1971 rainfall
had the highest recorded values in each month from March to September. Such rainfalls were not recorded at any 
of the otner rainfall stations and a detailed review of these records is required for future analyses.
In the probability of exceedance curves, the recorded annual rainfalls were calculated as a ratio of the mean recorded value and were plotted against the probability of occurrence. Probabilities were calculated using the following formula.B-37
where
Pi = probability of the ith ranked value of the
series
i = rank of the value in the series
n = total number of values in the series
The two curves for Sheno and Sendafa were averaged and the results are shown on Plate B-3, Figure 2. It is
noted that the area below the curve represents the dimensionless annual rainfall volume expressed as a function of the mean annual rainfall.
(d)      The extended and historic discharge records of the Chacha and Muger are shown in Table B.4. The annual discharges were ranked and the corresponding probabili ties of occurrence were calculated, utilizing the above formula.
(e)      It is noted that the calculated probabilities of the
ranked Muger and Chacha discharges are based on a 19-yr record. To determine the correspondingly ranked annual rainfalls, the probability of exceedance rainfall curve was entered utilizing these probabilities (abscissa) and considering the calculated mean annual rainfalls at the Chacha and Muger gauging stations (ordinate).
(f)       A typical rainfall/runoff relationship for the Aleltu
Basin was determined by plotting the ranked rainfall and discharge data calculated in Steps (d) and (e) above. This is shown on Plate B-3, Figure 3.B-38
It is noted that the plotted rainfall/runoff relation
ship is based on annual data series. It is assumed in 
the analysis below that this relationship is also valid 
for establishing monthly runoff series with a typical seasonal variability as defined by the flow records of the Chacha station.
(g)       The areas of the subbasins were determined from avail- aDle 1:50 000- and 1:250 000-scale topographic maps.
(n) Monthly discharge records for each of the subbasins of
the Aleltu project were derived based on the Markov single-step sequential simulation method and using single-seeded random numbers. For this purpose, the monthly means, monthly standard deviation and monthly serial correlation coefficients of the Chacha discharge record were calculated for use in the Markov recursion formula, shown below.
where
= generated streamflow in month "i+1"
= mean of observed flows in month "j+1" Qi = generated flow in month "i"
Qj = mean of observed flow in month "j"
bj = regression coefficient of month "j+1" in monthB-39
t = random number selected from a normal distribution having a zero mean and unit variance
°j+l = standard deviation of observed flows for
calendar month "j + 1"
rj = corelation coefficients describing the relation 
of flows for months "j+1” to flows for month n j ■■
From the synthetically generated monthly inflow sequences, the annual and long-term mean annual inflows were determined.
(i) Using the rainfall/runoff relationship determined in 
Step (f), the long-term mean annual runoffs for each subbasin were calculated and were compared to the synthetically derived long-term mean annual runoffs.
(j) The synthetically generated monthly inflow sequences were multiplied by the ratio of the mean annual calculated runoff to the mean annual generated inflow, to arrive at the inflow sequences used in the final layout optimization model runs.
The results of the analyses are shown in Table B.8.
B5 - EVAPORATION ANALYSES
For the preliminary hydrologic analyses, the effects of evaporation losses were not considered. However, for the detailed hydrologic analyses, an estimate of expected reservoir evaporation losses was made.B-40
TABLE B.8
MONTHLY INFLOW SEQUENCES OF SUBBASINS
GENERATED MONTHLY DISCHARGES (nr 3/S)
BASIN NAME: BASIN NO.:
AGAT 3a
DRAINAGE AREA:      92            km 2
PRECIPITATION:       1283        mm/yr
AVG RUNOFF:       430         mm/ yr
RUNOFF COEFF:      oo • 5        7.
DISCHARGE
YEAR        J           F          M          A
MJ
(m 3/S)
J  A S 0 N D /R
1
0.04 0.04
0.04
0.04
0. 03    0. 03
1.1
5.7
2.65
0. 09
0. 04    0.04
0.
0.04 0.04
0.08
0.04
0.00     0. 13
5.9
7.8
2.54
0.04
0. 03    0.02
1.
0.04 0.0.3
0.04
0.03
0. 03    0.00
2.4
5. 7
1. 17
0.09
0.04     0.03
0.
4
0.04 0.04
0. 13
0.07
0. 15    0. 05
1.3
11.1
1.57
0. 04
0. 05    0. 04
1.
5
0.05 0.05
0.02
0.03
0.02     0.00
3.4
5.7
0.42
0. 10
0. 15    0.03
0.
6
0.04 0.04
0.04
0.04
0.05     0. 14
4. 7
25.7
0.82
0. 1 3
0.03     0. 04
2.
7
0.04 0.03
0.04
0.04
0.04     0.02
0. 1
6.9
1.85
0.06
0. 04    0.03
0.
8
0.04 0.03
0.02
0.05
0.08     0.02
8.0
6. 8
0. 45
0. 12
0.04     0.02
1.
9
0.04 0.05
0. 03
0.03
0.05     0.01
0. 1
8.4
1.62
0. 14
0.04     0.04
0.
10
0.03 0.03
0.03
0.06
0.04     0.46
1.3
2.0
1.63
0. 04
0. 15    0. u4
0.
11
0.03 0.03
0.02
0.05
0.04     0.02
2.4
8.6
2.50
0. 14
0. 14    0. 05
1.
12
0.02 0.01
0.04
0.05
0.04     0.04
5.8
4. o
1.83
0. 07
0. 15    0. 04
1.
13
0.04 0.03
0.03
0. 05
0.05      1.32
8. 1
24. 1
1.27
0. 10
0. 04    0. 03
14
0.03 0.03
0. 04
0.05
0.04     2.78
11.4
9.2
_* • 03
0. 12
0.03     0.02
O
15
0.03 0.02
0. 03
0. 03
0. 1 1   2.78
10. 7
9.0
2.88
0.09
0. 02    0.02
o -- ■
16
0.04 0.05
0.05
0. 13
0.07     0. 13
-•. o
6. 5
1.86
0.03
0. 04    0. 04
1.
17
0•03 O.03
0.04
0. 16
0. 1 1   0. 04
3.9
4.5
1.07
0. 10
0. 02    0. 04
0.
18
0.03 0.01
0. 06
0.02
0.03     0.03
5.8
o. 8
1.30
0.08
0.03     0.04
1.
I?
0.03 0.03
0. 05
0.03
0. 07     0.01
1.2
5. 3
i .84
0.09
A. 02    0. 07
n.
20
0.04 0.08
0.06
0. 03
0.04     0.04
4.2
2.8
1.80
0. 09
0. 05    0. 03
0.
AVG
0.04 0.03
0. 05
0. 05
0.06      0. 40
4. 3
8.3
1.71
0. 09
0. 06    0.03
l.
S.D.
0.01 0.02
0.03
0.04
0.04     0.07
3. 3
6. 1
0. 74
0. 03
0.05     O.01
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TABLE B.8
MONTHLY INFLOW SEQUENCES OF SUBBASINS
GENERATED MONTHLY DISCHARGES (m 3/S)
BASIN NAME:
BASIN NO.: DRAINAGE AREA:
AGAT
3a
92
km"'-2
PRECIPITATION:
1293
mm/yr
•
■I
AVG RUNOFF:
430
mm / yr
RUNOFF COEFF:
33. 5
7.
■i
DISCHA
RGE
X
(m 3/S)
YEAR J
A
MJ
J 
A
S
0
ND
r’R
■
1     0.04      0.04      0.04      0.04     0.03     0 ■ Oo       1.1          5.7       2.65       0. 09  0. 04    0.04         0.3
2     0.04      0. 04     0.08     0.04     0.00     0. 13          5.9          7.8       2.54       0. 04  O. 03   0. 02        1.4
3     0.04      0. 03     0.04      0.03     0.03     0.00           2.4          5.7       1. 17        0.09  0.04     0.03       (>. 8
5     0.05      0.05      0.02     0.03     0.02     0.00           3.4          5.7       0. 42       0. 10  O. 15   0. <>3     0. 8
4     0.04
0. 04     0. 13     0.07     0. 15    0.05            1.3       11.1        1.57        0.04  0. 05    0. 04        1.2
6     0.04      0. 04     0.04      0.04     0.05     0. 14
4.7       25.7       0.82        0. 13  0.03     0.04        2. 6
7     0.04      0-03     0.04      0.04      0.04     0.02           0. 1         o.9        1.85       0. 06  0. 04    0. 03       0. 8
0     0.04      0.03      0.02     0. 05     0.00     0.02            8.0          6.8       0. 45       0. 12  0. 04    0. 02        1.3
10      0.03      0.03     0.03      0.06      0.04     0. 46           1.3         2.0       1.63       0. 04  0. 15    u. 04       0. 5
9     0.04      0. 05     0. 03     0. 03    0.05     0.01           0. 1         8. 4       1.62      0. J 4  0.04     0.04        0. 9
11     0.03      0 • 03    0.02     0. 05     0. 04    0.02            2.4         8. 6       2.50       0. 14  0. 14    u. ».'□      1.2
12     O.02     0 • 01    0.04      0. 05     0.04     0. 04           5.8         4. o       1.83       0. 07  0. 15    0. 04       t . 1
13      0.04
14     0.03
15     0.03
16     0.04
17        O.03
ia          0.03
jQ 0.03
Zu 0.04
AVG 0.04
S.D. 0.01
0. 03     0. 03     0. 05     0. 05     1.32
8. 1      24. 1        1.27       0. 10  0.04      0. 03        2.9
0. 02     0. 03     0.03      0. 1 1   2. 73        10. 7         9.0       2.88     <>. 09  0.02     0.02        2. 1
0 03      0. 04     0. 05    0.04     2.78         11.4          9.2       3.03        0. 12  <>. 03  0.02
0.05 0. 13 0.07 0. 13 0.03 0.04 0. Is 0. 11 0.04 n o t 0. 06 0. 02 0.03 0. 03
6.5       1.36        0.03  0. 04    O.»<4      1.0 3.9          4.5        1.07       0. 10  t1.02    0.04         0.3
5.5 5.8 1.30 0.08 0. 03 0.04 1 . 1
n o 3 0. 05 0. Oo 0.07 0.01 1.2 5- 1.84 0.09 0.02 0.03 0.7
0. 08 0.06 0.03 0. 04 0.04 4.2 2.8 1.80 0. 09 0.05 0. 03 0.8
t"i (“) T 0. 05 0.05 0.06 0. 40
0.02 0. 03 0.04 0.04 0.37
4.3          8.3       1.71        0. 09  0 . 06   0.03         1.3 333        6. 1       0.74        0. 03  0. 05    • >. 01B-41
Table B.8
Monthly Inflow
Sequences of Subbasins - 2
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:      TINISHU
BASIN NO.:      4b
DRAINAGE AREA:      37           km ^2
PRECIPITATION:       1231        mm/yr
AVG RUNOFF:      404          mm/yr
RUNOFF COEFF:       32.0        7.
DISCHARGE (m^3/S)
YEAR
J
F
M
A
M
J
J
A
s
0
ND
YR
1
0.02
0.01
0.01
0.06
0.04
0.01
1.9
3.0
0.67
0.03
0.02      0.01
0.5
2
0.02
0.02
0. 16
0.04
0.02
0.03
2.3
2.3
0.84
0.02
0.01      0.01
0.5
3
0.01
0.01
0.01
0.01
0.01
0.01
0.5
2.6
0.44
0.03
0.02      0.02
0. 3
4
0.02
0.02
0.06
0.06
0.04
0.00
1.0
3.4
0.52
0.02
0.01      0.01
0.5
5
0.01
0.01
0.02
0.02
0.02
0.01
2.2
1.8
0. 18
0.09
0.02     0.01
0.4
6
0.02
0.02
0.01
0.01
0.02
0.01
0. 3
5.0
0. 16
0.04
0.02      0.01
0.5
7
0.01
0.01
0.01
0.05
0.04
0.02
1.3
1.8
0.82
0. 10
0.01      0.01
0.3
8
0.02
0.02
0. 16
0.05
0.04
0.03
0. 1
4.3
0.40
0.09
0.01      0.02
0.4
9
0.02
0.01
0.01
0.02
0.02
0.01
1.9
10.2
0.85
0.09
0.06      0.02
1.1
10
0.02
0.02
0.01
0.02
0.03
0.09
1.4
4. 1
0. 15
0.02
0.02      0.01
0.5
11
0.01
0.01
0.01
0.01
0.01
0.01
1.9
3. 1
1.24
0.04
0.01      0.02
O. 5
12
0.02
0.01
0. 15
0.06
0.04
0.03
1. 1
4.3
1. 10
0.03
0.06      0. 02
0.6
13
0.01
0.01
0.07
0. 03
0.03
0.02
1.3
1.9
0.64
0. 03
0.01      0.01
0. 3
14
0.01
0.02
0.01
0.01
0.01
0.01
0.4
1.8
1.01
0.02
0.02      0.01
0. 3
15
0.02
0.02
0.02
0.05
0.04
0.02
2.5
3.0
0.86
0. 03
0.02      0.01
0.5
16
0.02
0.01
0.01
0.01
0.02
0.01
1.2
1.8
0.78
0.04
0.04      0.02
0.3
17
0.02
0.02
0.01
0.01
0.01
0.02
1.9
2.2
1.04
0.08
0.01      0.01
0. 4
18
0.01
0.01
0.01
0.05
0.05
0.02
0.2
1.8
0.70
0.01
0.02      0.01
19
0.01
0.01
0. 15
0.05
0.03
0.2
0.08
1.5
6.6
1.34
0.07
0.02      0. 01
0.3
20
0.01
0.01
0.01
0.01
0.03
0.02
1.4
2.8
0.39
0.02
0.06      0.02
0. 4
AVG
0.01
0.01
0.05
0.03
0. 03
0.02
1.4
3. 4
0.71
0.04
0.02      0.01
0.5
S.D.
0. 00
0.00
0. Ob
0.02
0.01
0.02
0.7
2. 1
0.35
0.03
0.02      0.00B-42
Table B.8
Monthly Inflow Sequences of Subbasins - 3
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME: BASIN NO.:
DRAINAGE AREA:
PRECIPITATION: AVG RUNOFF:
RUNOFF COEFF:
TILIKU
5b
450 knT2 1108 mm/yr 383 mm/yr 0^2 ■ .z.    /■
DISCHARGE (m 3/S)
YEAR
J
F
M
A
M
J
J
A
S
0
N□
YR
1
0. 13
0.32
0.72
0.30
0.24
0.63
30.4
42.0
4. 10
0.34
0.20     0. 16
6.6
2
0. 10
0.20
0.41
0.28
0.60
0.30
17.8
41.4
9.28
0. 15
0.71     0. 15
6.0
3
0. 15
0. 13
0.22
0. 19
0.22
0. 10
26. 1
19. 1
13.02
1.07
0. 12    0. 17
5. 1
4
0.22
0. 16
0.64
0.29
0.24
0.60
4.5
39.2
9.73
0.47
0. 17    0. 16
4.7
5
0. 14
0.08
0. 10
0. 15
0.52
0.44
3.0
70.9
4.95
0. 15
0.23     0.20
6.7
6
0. 18
0. 13
0. 16
0.51
0.39
0.08
11.9
29.4
11.34
0.42
0.52     0. 15
4.6
7
0. 21
0. 17
0.09
0. 42
0.28
0.23
26.6
26.9
0.96
0.26
0.23     0. 18
5.4
8
0. 18
0.81
0.54
0. 35
0.48
0.23
10.5
27.0
14.78
0.50
0.37     0.20
4.7
9
0. 15
0.04
0.27
0. 12
0.21
0. 18
16.0
12.2
10.06
1.22
0. 17    0. 16
3.5
10
0. 17
0.08
0.21
0. 13
0. 13
0.04
0.6
24.0
7.76
0. 36
0.51     0.20
2.9
11
0. 17
0. 12
0.22
0. 18
0.00
0.09
5.4
110.6
12.07
0.37
0.70     0.20
10.9
12
0. 15
0. 12
0. 14
0. 13
0. 16
0. 14
9.9
39. 4
9. 19
0.37
D. 17   0. 19
5.0
13
0.21
0. 22
0. 14
0.29
0. 16
0. 16
20.4
29.8
1.78
1.02
0. 1 1   0. 16
5.2
14
0. 16
0. 1 1
0.21
0. 17
0. 17
0. 18
14.7
28.2
9.74
0. 38
0.09     0. 16
4.5
15
0. 21
0.07
0. 1 1
0.07
0.00
0.45
29.2
61.2
6.02
0.95
0.23     0. 18
8.2
16
0. 15
0.09
0.67
0.36
0.41
0.32
19.2
18.8
2.41
0. 10
0. 18    0. 13
3.6
17
0. 20
0. 20
0. 48
0.37
0.29
0.56
4.0
27.2
0.97
1. 13
0.09     0. 15
3.6
1A
0. 17
0. 19
0. 1 1
0.21
0.37
0.34
3.5
43.3
9.24
0.26
0. 13    0. 12
4.8
19
20
0. 20
0. 15
0.21
0.20
0.22
0. 10
0. 19
0. 17
0.50
0. 17
0. 14
0.09
13.8
02.3
14. 45
0.55
0. 23    0. 14
9.3
34.8
26. 3
4. 76
0.26
0.23     0. 18
5.6
nVU
S. D.
0. 17
0. 22
0.29
0.24
0.29
0.27
15. 7
40.0
8.67
0.52
0.27     0. 17
5.6
0. 03
0.22
0.21
0. 12
0. 17
0. 18
10.7
24. °
3.74
0.35
0. 19    0.02B-43
Table B.8
Monthly Inflow
Sequences of Subbasins - 4
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:       JIDA
BASIN NO.:       6c
DRAINAGE AREA:       749              km 2
PRECIPITATION:       1103         mm/yr
AVG RUNOFF:       342            mm/yr
RUNOFF COEFF:       31.1         7.
DISCHARGE    (m '3/S>
YEAR        J           F          M          A           M          J              J              A              S              0           N           D           YR
1        0.25  0.22      0.29      1.07     0.77      0. 16           26.6        96. 7   20. 45            0.73   0. 93     0.27         12. 4
2        0.24   0.23      0.25      1.05     0.92      0.29             21.0         11.9       4.52           0.56   0.31      0.22           3. 4
3       0. 19   0.20      0.22      0.27      0.33      0. 12         111.5         41.8   19.68             0.68   0.24      0. 16         14.6
4        0.27   0.29      0. 19     0.22      0.32      0.05              1.7        17. 3       5.90          0. 03   0.69      0.25            2.3
5       0. 14   0. 16     0. 33     0. 33     0.31      0. 18           28.7         54.6       8. 05          0.29   0.61      0. 25           7.8
6        0.20   0.20      0.27      0.23      0. 17     0.33            23.2         62.8       7. 39         0. 50   0.99      0.31          9. 1
7        0.34   0.35      0.30      0.23      0.24      0. 16           31.9       127.9   18. 15            1.34   0. 77     0.29          15.2
0        0.29   0.29      0. 12     0. 16     0.20      9. 15           25.9       35. 1    14. 49            1.24   0.99      0.23            7.3
9       0. 19   0. 19     0.30      0.34      0.3018.14                 79.5         36.6   19.63             1.26   0. 12     0. 20         13.0
10        0.30   0.33      0.90      0.45      0.4612.97                 51.3       50. 1    12.27            0. 35   0. 13     0. 12         10.8
11
0.22
0. 16
0. 29
0. 19
0. 18
0.25
21.9
63.9
12
0.22
0.01
0. 11
0. 09
2. 86
0. 46
0. 00
0. 26
0.24
0.25
7.6
36. 1
74. 1
13
0.24
0.26
0. 44
0.27
11.21
0.34
0.72
0. 12
0.23
10. 3
0.24
6.7
14
0. 19
0. 13
52. 4
0.33
0.25
4.97
0.44
0. 14
0. 45
0. 13
0.24
5. 6
8^ ■ 0
15
0.25
0.24
0.23
0.45
1.20
0. 43
n-r -r
42.6
7.26
0.26
0. 17
0.25
11.2
16
0.27
0.21
0.90
55. 1
0.40
9. 29
0. 53
0.29
0. 24
0. 18
0. 79
9. 1
7.6
36. 4
17
0. 18
0. 10
0.23
0. 19
16.57
0.26
0.40
0.27
0. 13
0. 14
5. 4
21.9
10
0. 23
0.24
0. 12
0. 13
42.2
6. 11
0. 59
0.65
0.90
0. 16
0.20
6. 0
0. 12
2.8
19
0. 18
0.37
30. 7
1.09
7. 40
0.73
0.24
0.09
0. 21
0. 25
1.0
3. 6
20
0.30
0.23
0. 16
0. 15
0. IS
41.6
11.99
0.61
0.00
0. 23
0. 16
4.9
24.0
35. 1
11.79
0. 59
0. 93
0.24
6. 1
AVG
0.23
0.21
0.32
0. 39
0. 40
2. IS
31.5
S.D.
0.05
0.09
0.22
0.31
50.4
0. 30
10. 95
4.97
0. 58
0. 42
29.0
0. 25
a. i
26. 4
5.56
0.36
0.32
0. 13B-42
Table B.8
Monthly Inflow Sequences of Subbasins - 3
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:      TILIKU
BASIN NO.:      5b
DRAINAGE AREA:      459              km'2
PRECIPITATION:      1198         mm/yr AVG RUNOFF:      393          mm/yr
RUNOFF COEFF:      32.2         7.
I
A
S
0
ND
YR
42.0
4. IS
0. 34
0.20     0. 16
6. 6
41.4
9.28
0. 15
0.71     0. 15
6.0
19. 1
13.82
1.07
0. 12    0. 17
5. 1
39.2
9.73
0.47
0. 17    0. 16
4.7
70.9
4.95
0. 15
0.23     0.20
6.7
29.4
11.34
0.42
0.52     0. 15
4.6
26. 9
8.96
0.26
0.23     0. 18
5.4
27.8
14.78
0.50
0.37     0.20
4.7
12.2
10. 06
1.22
0. 17    0. 16
o.5
24.8
7.76
0. 36
0.51     0.20
2.9
1 10.6
12.07
0.37
0.70     0.20
10.9
39.4
9. 19
0.37
0. 17    0. 19
5.0
29.8
1.78
1.02
0. 1 1   0. 16
5.2
28.2
9.74
0. 38
0. 09    0. 16
4.5
61.2
6.02
0.95
0.23     0. 18
8.2
18.9
2.41
0. 10
0. 18    0. 13
3.6
27.2
8.97
1. 13
0.09     0. 15
3.6
43. 3
9.24
0.26
0. 19    0. 12
4.8
82.3
14. 45
0.55
0.23     0. 14
9.8
26.3
4.76
0.26
0.23     0. 19
5. 6
40.0
8.67
0.52
0.27     0. 17
5.6
24.2
3.74
0.35
0. 19    0.02B-43
Table B.8
Monthly Inflow Sequences of Subbasins - 4
GENERATED MONTHLY DISCHARGES (m 3/S)
x
BASIN NAME:       JIDA
BASIN NO.:      6c
DRAINAGE AREA:      749           kmz’ 2
PRECIPITATION:       1103        mm/yr
AVG RUNOFF:      342           mm/yr
RUNOFF COEFF:      31. 1        7.
DISCHARGE (m'3/S>
YEAR       J          F          M          A
M          J             J              A             s         □      N          D          YR
11
1        0.25  0.22     0.29      1.07     0.77     0. 16          26.6        96.7    20.45          0.73   0.83      0.27         12.4
2        0.24  0.23     0.25      1.05     0.92     0.28           21.0        11.8       4.52          0.56  0.31      0.22           3.4
3       0. 19  0.20     0.22     0.27     0.33     0. 12        111.5        41.8     19.68          0.68  0.24      0. 16        14.6
4        0.27  0.2S     0. 19    0.22     0.32     0.05             1.7        17.3       5.90          0.03   0.69      0.25           2.3
5       0. 14   0. 16    0.33     0.33     0.31     0. 18          28.7        54.6       8.05          0.29   0.61      0.25           7.8
6        0.20  0.20     0.27     0.23     0. 17    0.33           23.2        62.8       7.39         0. 50  0.99      0.31         8. 1
7        0.34   0. 35    0.30     0.23     0.24      0. 16          31.9      127.9    18. 15         1.34   0.77      0.29         15.2
8        0.29  0.29     0. 12    0. 16    0.20     8. 15          25.8       35. 1     14. 48          1.24  0.99      0.23           7.3
9       0. 19  0. 18    0.30     0.34     0.3018.14               78.5       3a. 6     19.63          1.26   0. 12     0.20        13. 0
10 0.30 0.33 0.90 0.45 0.4612.97 51.3 50. 1 12.27 0. 35 0. 13 0. 12 10.8
0.22
0. 16
0.29
0. 19
0. 18
0.25
21.9
63.9
0.01
0. 11
2.86
12
0.22
0.08
0.00
0. 46   0.26      0.25
0.24
7.6
36. 1
74. 1
13
0.24
0.26
0.44
0.27
11.21
0.34
0.72   0. 12     0.23
0. 24
10.3
6.7
52.4
4.97
14
0. 19
0. 13
0.33
0.25
0. 14
0.44   0. 13     0.24
0.45
5. 6
83.0
42.6
15
0.25
0.24
0.23
0. 45
7.26
1.20
0.26   0. 17     0.25
0.43
11.2
23.3
55. 1
8.29
16
0.27
0.21
0.90
0.40
0. 28
0. 18
0.53   0.24      0.78
7.6
9. 1
36. 4
17
0. 18
0. 10
0.23
0. 19
16.57
0.26
0. 13
0. 40   0.27      0. 14
5. 4
21.9
0.23
42.2
6. 11
IB
0.24
0. 12
0. 13
0.65
0.90
0.59   0. 16     0.20
6. 0
2.8
30.7
19
0. 18
0. 12
0.37
1.00
7. 40
0.73
0.24
0.08  0.21      0.25
3. 6
1.0
41.6
20
0.30
0.23
0. 16
0. 15
11.93
0. IB
0.00
0.61   0.23      0. 16
4.9
24.0
35. 1
11.79
0. 59   0.93      0.24
6. 1
AVG
0.23
0.21
0.32
0. 38
0. 40
2. 18
31.5
50. 4
S.D.
0.05
0.08
0.22
0.31
10. 95
0. 30
4. 97
29.0
0. 58   0. 42     0. 25
8. 1
26. 4
5.56
0. 36   0.32      0. 13B-44
Table B.8
Monthly Inflow Sequences of Subbasins - 5
GENERATED MONTHLY DISCHARGES (m''3/S)
BASIN NAME:      GOMORO
BASIN NO.:      8a
DRAINAGE AREA:      225              km'2
PRECIPITATION:
1092
mrn/yr
AVG RUNOFF:
337
irim/yr
RUNOFF COEFF:
30.9
7.
DISCHARGE ((TT3/S)
YEAR
J
F
M
A
M
J 
J 
A
s
0
N
D
YR
1
0.04
0.02
0.09
0. 11
0. 12
0.26
13.2
10.8
4.76
0.21
0.29
0.08
2.5
2
0.04
0.02
0.03
0.03
0.03
0.04
11.0
7.0
3.49
0. 12
0.29
0.08
i.a
3
0.07
0.07
0.53
0. 15
0.06
0.05
5.6
6.4
3.60
0.25
0.05
0.04
1.4
4
0. 09
0.08
0.04
0. 16
0.09
0.07
2.4
20.3
1.74
0.33
0.07
0.07
2. 1
5
0.09
0.09
0.09
0.24
0.36
4.22
22.0
17.5
3.65
0. 17
0.25
0.05
4. 1
6
0. 09
0.06
o.oa
0. 17
0. 14
2.24
10.8
8.6
3.56
0.34
0.22
0. 18
2.2
7
0.08
0.08
0.27
0. 12
0.06
0.07
18. 1
10.8
4.71
0. 14
0.06
0.04
2.9
8
0. 04
0.04
0. 11
0.04
0.03
0.07
0.8
13.8
0.63
0.24
0.08
0.37
1.4
9
0. 10
0. 08
0.02
0.04
C.25
0.06
6.0
13.6
2.20
0.02
0.20
0.07
1.9
10
0.04
0.04
0.04
0.20
0. 17
0. 14
4.6
30. 6
4.08
0.24
0.04
0.04
3.3
11
0.09
0. 05
0. 06
o.oa
0.26
0.06
2.5
io.e
5. 03
0.27
0.08
0.06
1.6
12
0. 08
0.08
0. 05
0.04
0. 19
0.41
2.7
12.2
4.04
0. 17
0.04
0.07
1.7
13
14
0.0a
0.04
0.09
0.05
0.02
0.09
9.0
8.8
2.34
0.09
0.04
0.07
1.7
o. oa
0.06
0.27
0. 11
0. 12
0.08
9.9
10.6
3.94
0.07
0.04
0.06
2. 1
15
0. 08
0.07
0.09
0.07
0.07
0.07
0.03
0. 11
0.05
0. 16
0.01
0.04
4.6
10. 1
3.24
0. 10
0.09
0.07
1.5
1a
1.0
55.9
6.61
0.22
0.25
0.0a
5.4
17
0.07
0.07
0. 06
0.25
0. 19
0. 11
23.4
24.3
0.84
0.20
0.07
0.06
4. 1
19
0. 05
0.05
0. 27
0. 12
0. 10
0. 10
6.6
13.5
5.85
0.28
0.28
0.39
2.3
19
0. 13
0. 14
0. 12
0.32
0.21
0.03
0.4
21.2
3.92
0. 15
0.09
0.07
2.2
20
0.07
0.08
0. 11
0.05
0.07
0.04
4.9
16.6
1.42
0.05
0.04
0.04
2.0
AVG
S.D.
0. 07
0. 02
0.07
0.03
0. 12
0. 12
0. 12
o. oa
0. 13
0.09
0.41
1.02
8.0
16.2
3.48
0. 18
0. 13
0. 10
2.4
6.8
11.2
1.58
0.09
0. 10
0. 10B-45
Table B.8
Monthly Inflow Sequences of Subbasins - 6
GENERATED MONTHLY DISCHARGES (m' 3/S)
s
BASIN NAME: Robi
BASIN NO.:      9a
DRAINAGE AREA:      437            km~2
PRECIPITATION:       1030        mm/yr
AVG RUNOFF:      309           mm/yr
RUNOFF COEFF:       30.0         7.
DISCHARGE (m' 3/S)
s
YEAR
J
F
M
A
M
J 
J 
A
S
□ND
YR
1
0. 12
0.09
0. 14
0.11
0. 17
0.08
11.9
24. 1
6. 49
0.80   0.00      0. 10
3.7
2
0.11
0. 16
0. 15
0.06
0.09
0.20
2.2
77.4
9.04
0.52   0.09      0.00
7.5
3
0. 10
0.08
1.20
0.35
0.20
0.05
12.9
18.9
8.77
0.70   0. 14     0. 12
3.6
4
0.09
0.06
0.07
0.09
0. 16
0.09
20. 1
28.2
5. 14
0. 15   0. 11     0.06
5
0. 13
0. 16
0.09
0.07
4.5
0.09
0. 17
4.0
24.5
7.73
0.83   0.47      0. 16
6
0.00
0.05
0. 10
0.52
3.2
0.39
0.99
26.9
15.7
7.46
7
0.82  0. 11     0. 13
0. 12
0.09
0. 15
0.07
0.00
5. 1
0.06
30.6
10.3
3.28
0
0. 13
0. 10
0. 16
0.09
0. 11   0. 11     0.07
0.00
3.0
0.08
10.4
12.0
9
5.80
0.11
0.00
0. 13
0.52
0. 17   0.09      0.24
0.38
8.99
2.5
36.2
38.0
10
0. 16
0. 14
0 ■ Oo
0.48
6.42
0.34
0. 19   0. 13     0. 10
7.6
0.06
4.0
0.00
29.0
5.71
11
0.05
0. 16
0. 12
0.09
0.20  0. 40     0.09
3.4
6.38
35. 0
20.6
5. 10
12
0. 12
0.08
0. 44
0.23
0.00
0.27  0.49      0. 14
0. 12
5. 7
0.9
0. 10
16.4
13
0. 10
0. 11
0.52
3.81
0.37
0.30   0. 11     0. 16
0.34
1.9
50. 1
14
0. 10
0.55
0.51
25.5
0. 15
6.07
0.25
0.07
0. 17   0.09      0. 13
7.0
10.6
55.7
1.54
15
0. 13
0. 14
1.21
0.70
0.50
0.44   0.47      0.09
8.99
5. 9
25. 2
16
0. 17
0. 17
0.00
0.06
18.4
2.68
0. 10
0. 18   0. 12     0. 13
0. 10
4.9
4.2
36. 4
4. 07
17
0.00
0.09
0.06
0. 11
0. 13
0.05   0. 11     0. 10
0.05
3. 0
11.0
11.1
18
0. 14
0. 12
0. 1 1
0. 18
8.20
0.24
0. 13  0. 13     0.09
0.06
1.7
2.6
22.4
19
0. 11
0.33
0.09
0. 16
0. 17
4.26
0.09
0.20   0. 10     0.20
15.9
2. 5
21.7
20
0. 14
0. 05
0. 14
0. 12
4.04
0.23
0. j6
0. 66   0. 1 1    0. 11
16.0
3.6
19. 1
1.30
0.03   0.41      0. 10
3.2
AVG
0. 12
0. 13
0.26
0.24
0.20
1.77
16.5
S.D.
0.03
0. 12
0.35
26.3
0.21
5. 35
0. 13
3.41
0. 35   0.20      0. 12
4.3
13.6
16.0
2.25
0.27   0. 16     0.04B-44
12
Table B.8
Monthly Inflow
Sequences of Subbasins - 5
GENERATED MONTHLY DISCHARGES (m''3/S)
BASIN NAME:      GOMORO
BASIN NO.:      8a
DRAINAGE AREA:      225             km^2
PRECIPITATION:
1092
mni/yr
AVG RUNOFF:
337
ffim/yr
RUNOFF COEFF:
30.9
7.
DISCHARGE (m<3/S)
YEAR
J
F
M
A
M
J
J
A
S
0
N
YR
1
0.04
0.02
0.08
0.11
0. 12
0.26
13.2
10.8
4.76
0.21
0.29     0.08
2.5
2
0.04
0.02
0.03
0.03
0.03
0.04
11.0
7.0
3.49
0. 12
0.29     0.08
1.8
3
0.07
0.07
0.53
0. 15
0.06
0.05
5.6
6.4
3.60
0.25
0.05     0.04
1.4
4
0. 08
0.08
0.04
0. 16
0.09
0.07
2.4
20.3
1.74
0.33
0.07     0.07
2. 1
5
0.09
0.09
0.09
0.24
0.36
4.22
22.0
17.5
3.65
0.17
0.25     0.05
4. 1
6
0.08
0.06
0.08
0. 17
0. 14
2.24
10.8
8.6
3.56
0.34
0.22     0. 18
2.2
7
0.08
0.08
0.27
0. 12
0.06
0.07
18. 1
10.8
4.71
0. 14
0.06     0.04
2.9
0
0.04
0.04
0. 11
0.04
0.03
0.07
0.8
13.8
0.63
0.24
0.08     0.37
1.4
9
0. 10
0.08
0.02
0.04
C.25
0.06
6.0
13.6
2.20
0.02
0.20     0.07
1.9
10
0.04
0.04
0.04
0.20
0. 17
0. 14
4.6
30.6
4.08
0.24
0.04     0.04
3. 3
11
0.09
0.05
0.06
0.08
0.26
0.06
2.5
10.8
5.03
0.27
0.08     0. 06
1.6
12
0. 08
0.08
0.05
0.04
0. 19
0.41
2.7
12.2
4.04
0. 17
0.04     0.07
1.7
13
0. 06
0.04
0.08
0.05
0.02
0.09
9.0
8.8
2.34
0.09
0.04     0.07
1.7
14
0.08
0.06
0.27
0. 11
0. 12
0.08
9.9
10.6
3.94
0.07
0.04     0.06
2. 1
15
0. 08
0.09
0.07
0.03
0.05
0.01
4.6
10. 1
3.24
0. 10
0.09     0.07
1.5
16
17
0.07
0.07
0.07
0. 07
0.07
0.06
0. 11
0.25
0. 16
0. 19
0.04
0. 11
1.0
55.9
6.61
0.22
0.25     0.06
5.4
23.4
6. 6
24.3
0.84
0.20
0.07     0.06
4. 1
18
0. 05
0. 05
0.27
0. 12
0. 10
0. 10
13.5
5.85
0.28
0.28     0.39
2.3
19
20
0. 13
0. 07
0. 14
0.08
0. 12
0. 11
0.32
0.05
0.21
0. 07
0.03
0.04
0.4
21.2
3.92
0. 15
0.09     0.07
2.2
4.9
16.6
1.42
0.05
0.04     0.04
2.0
AVG
S.D.
0.07
0. 07
0. 12
0. 12
0. 13
0.41
8.0
16.2
3.48
0.18
0. 13    0. 10
2.4
0.02
0.03
0. 12
0.08
0.09
1.02
6.8
11.2
1.58
0.09
0. 10    0. 10
1 1 ia i
iB-45
Table B.8
Monthly Inflow Sequences of Subbasins - 6
GENERATED MONTHLY DISCHARGES (m'"3/S)
BASIN NAME:         Robi
BASIN NO.:        9a
DRAINAGE AREA: 437 kmzX2
PRECIPITATION:        1030          mm/yr AVG RUNOFF:        309             mm/yr
RUNOFF COEFF:         30.0           7.
DISCHARGE (m'3/S)
YEAR
J
F
M
A
M
J
J
A
S
0
N
D
YR
1
0. 12
0.09
0.14
0.11
0. 17
0.08
11.9
24. 1
6.49
0.80
0.08
0. 10
3.7
2
0. 11
0. 16
0. 15
0.06
0.09
0.20
2.2
77.4
9.04
0.52
0.09
0.08
7.5
3
0. 10
0.08
1.20
0.35
0.20
0.05
12.9
18.9
8.77
0.70
0. 14
0. 12
3.6
4
0.09
0.06
0.07
0.09
0. 16
0.09
20. 1
28.2
5. 14
0. 15
0. 11
0.06
4.5
5
0. 13
0. 16
0.09
0.07
0.09
0. 17
4.0
24.5
7.73
0 ■ 8o
0. 47
0. 16
3.2
6
0.08
0.05
0. 10
0.52
0.39
8.99
26.9
15.7
7.46
0.82
0. 11
0. 13
5. 1
7
0. 12
0.09
0. 15
0.07
0.08
0.06
30.6
10.3
3.28
0.11
0. 11
0.07
3.8
8
0. 13
0. 10
0. 16
0.09
0.08
0.08
10.4
12.8
5.80
0. 17
0.09
0.24
2.5
9
0. 11
0.08
0. 13
0.52
0.38
8. 99
36.2
38.0
6.42
0. 19
0. 13
0. 10
7.6
10
0. 16
0. 14
0.03
0.48
0. 34
0.06
4.0
29.0
5.71
0.20
0. 48
0.09
3.4
11
0.08
0.05
0. 16
0. 12
0.09
6.38
35.0
20.6
5. 10
0.27
0.49
0. 14
5.7
12
0. 12
0.08
0. 44
0.23
0.00
0. 12
0.9
16.4
3. 81
0.30
0. 1 1
0. 16
1.9
13
0. 10
0. 11
0. 10
0.52
0.37
0.34
50. 1
25.5
6.07
0. 17
0.09
0. 13
14
0. 10
0.55
0.51
0. 15
7.0
0.25
0.07
10.6
55. 7
1.54
0.44
0. 47
0. 09
5. 9
15
0. 13
0. 14
1.21
0.78
0.50
8.99
25.2
18. 4
2. 68
0. 18
0. 12
0. 13
16
0. 17
0. 17
0.08
0.06
4. 9
0. 10
0. 10
4.2
36. 4
4.07
17
0.08
0.09
0.05
0. 11
0.06
0. 10
0. 11
0. 13
3. 8
0.05
11.0
11.1
8.20
0. 13
0. 13
18
0. 14
0. 12
0. 11
o. le
0.09
0.24
2.6
0. 06
1.7
22.4
4.26
0. 20
19
0. 11
0.33
0.09
0. 16
0. 10
0. 17
0.20
2. 5
0.09
15.9
21.7
4.04
0.66
0. 11
0. 11
20
0. 14
0.05
0. 14
0. 12
0.23
3. 6
0 • ^»6
16.0
19. 1
1.30
0.03
0. 41
0. 10
3.2
AVG
0. 12
0. 13
0.26
0.24
0.20
1.77
16.5
26.3
5.35
0.35
0.20
0. 12
S. D.
0.03
0. 12
0.35
0.21
0. 13
4.3
3.41
13.6
16.0
2.25
0.27
0. la
0.04B-46
Table B.8
Monthly Inflow Sequences of Subbasins - 7
A
GENERATED MONTHLY DISCHARGES (m 3/S)
BASIN NAME:       WESERBI BASIN NO.:        2a
DRAINAGE AREA:         168               km-v2 PRECIPITATION:         1288            mm/yr
AVG RUNOFF:         432              mm/yr RUNOFF COEFF;         33.6           7.
DISCHARGE (m''3/S)
YEAR
J
F
M
A
M
J
J
A
s
0
N
D
YR
1
0 • 05
0.05
0.05
0.03
0.03
0.23
1.6
5.4
3.49
0. 10
0.07
0.06
0.9
2
0.07
0.05
0.08
0. 10
0. 11
0.20
2.5
18.2
5.48
0.27
0.05
0.07
2.3
3
0.08
0.08
0.06
0. 17
0.21
0.05
4.2
10.0
3. 76
0. 11
0.06
0.07
1.6
4
0.08
0. 10
0.08
0.05
0.00
0.05
8.4
6.9
4. 13
0. 19
0.08
0.07
1.7
5
0.08
0.08
0.01
0.05
0.04
0.04
10. 1
20.3
1.58
0.06
0.03
0.05
2.7
6
0.05
0.03
0.24
0. 14
0.28
0.23
9.2
5.4
4.30
0.23
0.23
0.07
1.7
7
0.05
0.04
0. 10
0.06
0.06
0.05
2.3
11.2
2. 18
0. 14
0.26
0.08
1.4
8
0. 08
0. 10
0. 11
0.07
0. 10
0.05
0.4
50.6
3.46
0. 18
0.05
0.04
4.6
9
0.05
0.02
0. 16
0.09
0.08
0.05
10.0
10.0
1.05
0.08
0.05
0.06
1.8
10
0.08
0.08
0. 10
0.09
0.08
0.06
30.0
16.8
1.53
0. 10
0.07
0.07
4. 1
11
0.08
0.06
0.05
0.09
0.05
0.24
9.3
4.2
2.97
0. 16
0.04
0.05
1.4
12
0. 06
0.06
0.06
0.05
0.07
0.05
2.2
11.9
1.73
0.30
0.26
0.07
1.4
13
0. 05
0.03
0.01
0.07
0.06
0. 18
4.7
6.5
5.20
0.39
0.06
0.03
1.4
14
0.06
0.06
0.05
0.07
0. 03
0. 10
1.9
11.0
0.79
0.03
0.06
0.06
1.2
15
0. 04
0.09
0. 15
0.07
0.00
0.05
2. 1
50.7
6.32
0. 13
0. 15
0.07
5.0
16
0. 08
0. 08
0.04
0. 10
0.31
0.23
12.8
6.6
0.43
0.28
0.05
0.03
1.7
17
0. 07
0. 07
0.56
0. 16
0. 34
0.07
0.4
12.0
4.47
0. 12
0.09
0.06
1.5
IB
0. 05
0.05
0.09
0.07
0.06
0.07
5.0
12.5
3.33
0. 17
0.07
0.07
1.8
19
0.04
0. 03
0.03
0.08
0.24
0.01
22.2
52.3
4.Cl
0. 18
0.09
0.04
6.6
20
0. 03
0.02
0.07
0. 15
0.22
0.05
1.9
11.0
0.08
0.09
0.07
1.3
AVG
0. 06
0.06
0. 11
0.09
0. 12
0. 10
7. 1
16. 7
3. 12
0. 16
0. 10
0.06
2.3
S. D.
0.02
0.03
0. 12
0.04
0. 11
0.08
7.6
15.5
1.65
0.09
0.07
0.01B-47
Table B.8
Monthly Inflow Sequences of Subbasins - 8
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:
DUBER
BASIN NO.:
12c
DRAINAGE AREA:
312
km''2
PRECIPITATION:
1225
mm/yr
AVG RUNOFF:
401
mm/yr
RUNOFF COEFF:
32.7
7.
J             F             M            A             M             J                 J                 A                 s         □      N             D              YR
DISCHARGE (m''3/S)
1
0. 16
0. 10
0.11
0.21
0. 19
0. 15
18. 1
24.7
7.27
0.29
0.48
0.20
4.3
2
0. 14
0. 10
0. 14
0. 12
0. 14
4.70
14.4
16.3
7. 48
0.44
0.07
0.09
3.7
3
0. 15
0. 11
0. 13
0. 10
0.38
0.09
11.1
29. 9
1.88
0. 10
0.50
0. 14
3.7
4
0. 16
0. 16
0. 10
0. 10
0. 12
1.52
20.5
30.2
8.86
0.36
0.09
0. 19
5.2
5
0. 16
0. 17
0.36
0.27
0.38
0.02
4.0
30.0
6.75
0.34
0. 12
0.09
3.6
6
0.08
0.00
0.07
0.11
0. 17
0.22
26.7
30.9
6.81
0.27
0.07
0.08
5.5
7
0. 12
0. 14
0. 16
0.36
0.31
0. 10
4.5
20.0
10.29
0.43
0.09
0. 14
3. 1
8
0.08
0.08
0.08
0. 10
0. 11
5.76
16.2
16. 4
6.53
0.33
0. 17
0. 15
3.8
9
0. 12
0. 13
0.09
0. 10
0.09
0. 06
20. 1
30.3
6.83
0. 35
0.07
0. 13
4.9
10
0. 11
0. 12
0. 11
0. 11
0.23
0.26
9.2
16.3
6.58
0- 33
0.52
0. 14
2.8
11
0. 17
0. 15
0. 16
0. 19
0. 17
0. 13
2.2
15.3
1.28
0. 14
0.30
0. 15
1.7
12
0. 16
0. 13
0. 12
0.11
0.09
0.27
14.5
44. 4
6.04
0.32
0. 51
0. 14
5. 6
13
0. 10
0. 10
0.24
0. 16
0.41
0. 03
20.6
27. 1
3. 80
0.45
0. 15
0. 10
4. 4
14
0. 12
0. 13
0.21
0.30
0.11
0.01
11.5
27.2
7. 59
0.28
0. 18
0. 14
15
0.00
0.08
0. 10
4. 0
0. 10
0. 06
0. 16
21.6
10. 5
3.83
0. 15
0. 17
16
0. 18
0- 19
0. 14
0.29
0.22
0.25
3. 1
0. 42
16. 1
25.7
1. 13
0. 06
17
0. 10
0.07
0.49
0. 14
0.30
0. 07
0.20
3. 7
0.07
12. 1
40.7
7.74
0.30
0.07
18
0. 11
0.06
0.20
0. 13
0. 1 1
0. 12
5.2
2. 29
15. 0
16.3
6. 72
0. 44
19
0. 13
0. 10
0. 16
0. 12
0. 15
0.11
0. 13
3. 5
0. 10
15.8
30. 3
5. 75
0. 17
20
0. 15
0.06
0. 49
0.29
0. 17
0. 40
0. 09
4.4
0. 17
0. 7
28. 7
9.21
0. 49
0.53
0. 15
3. 4
VS
0. 13
0. 11
0. 18
0. 18
0.20
0.83
13. 7
25.6
6. 12
.D.
0.03
0.04
0. 12
0. 30
0.09
0. 11
O. 23
0.13
4. 0
1.62
7. 0
8. 7
2.53
0. 12
0. 18
0.04B-46
Table B.8
Monthly Inflow Sequences of Subbasins - 7
GENERATED MONTHLY DISCHARGES (m~3/S)
BASIN NAME:       WESERBI BASIN NO.:        2a
DRAINAGE AREA:         168               kmzx2 PRECIPITATION:         1288            mm/yr
AVG RUNOFF:         432              mm/yr RUNOFF COEFF:          33.6           7.
DISCHARGE (m~3/S)
YEAR
J
F
M
A
M
J
J
A
s
0
N
D
YR
1
0.05
0.03
0.05
0.03
0.03
0.23
1.6
5.4
3.49
0. 10
0.07
0.06
0.9
2
0.07
0.05
0.08
0. 10
0. 11
0.20
2.5
18.2
5.48
0.27
0.05
0.07
2.3
3
0.08
0.08
0.06
0. 17
0.21
0.05
4.2
10.0
3.76
0. 11
0.06
0.07
1.6
4
0. 08
0. 10
0.08
0.05
0.00
0.05
8.4
6.9
4. 13
0. 19
0.08
0.07
1.7
5
0.08
0.08
0.01
0.05
0.04
0.04
10. 1
20. 3
1.58
0.06
0.03
0.05
2.7
6
0. 05
0.03
0. 24
0. 14
0.28
0.23
9.2
5.4
4.30
0.23
0.23
0.07
1.7
7
0.05
0.04
0. 10
0.06
0.06
0.05
2.3
11.2
2. 18
0. 14
0.26
0.08
1.4
8
0. 08
0. 10
0. 11
0.07
0. 10
0. 05
0.4
50.6
3.46
0. 18
0.05
0.04
4.6
9
0.05
0.02
0. 16
0.09
0.08
0.05
10.0
10.0
1.05
0.08
0.05
0.06
1.8
10
0.08
0.08
0. 10
0.09
0.08
0.06
30.0
16.8
1.53
0. 10
0.07
0.07
4. 1
11
0.08
0.06
0.05
0.09
0.05
0.24
9.3
4.2
2.97
0. 16
0.04
0.05
1.4
12
0.06
0.06
0.06
0. 05
0.07
0.05
2.2
11.9
1.73
0.30
0.26
0.07
1.4
13
0.05
0. 03
0.01
0.07
0.06
0. 18
4.7
6.5
5.20
0.39
0.06
0.03
1.4
14
0.06
0.06
0.05
0.07
0 ■ Oo
0. 10
1.9
11.0
0.79
0.03
0.06
0.06
1.2
15
0. 04
0.09
0. 15
0.07
0.00
0.05
2. 1
50.7
6.32
0. 13
0. 15
0.07
5.0
16
0.08
0.08
0.04
0. 10
0.31
0.23
12.8
6.6
0.43
0.28
0.05
0.03
1.7
17
0.07
0.07
0.56
0. 16
0.34
0.07
0.4
12.0
4.47
0. 12
0.09
0.06
1.5
T TT
18
0.05
0.05
0.09
0.07
0.06
0.07
5.0
12.5
0. 17
0.07
0.07
1.8
19
0. 04
0.03
0. 03
0. 08
0.24
0.01
22.2
52.3
4.Cl
0. 18
0.09
0.04
6.6
20
0.03
0.02
0.07
0. 15
0.22
0.05
1.9
11.0
2. 13
0.08
0.09
0.07
1.3
iVG
0. 06
0.06
0. 11
0.09
0. 12
0. 10
7. 1
16.7
3. 12
0. 16
0. 10
0. 06
2.3
i.D.
0.02
0.03
0. 12
0.04
0. 11
0.08
7.6
15.5
1.65
0.09
0.07
0.01B-47
Table B.8
Monthly Inflow Sequences of Subbasins - 8
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:
DUBER
BASIN NO.:
12 c
DRAINAGE AREA:
312
km~2
PRECIPITATION:
1225
mm/yr
AVG RUNOFF:
401
mm/yr
RUNOFF COEFF:
32.7
7.
DISCHARGE (m~3/S)
YEAR           J             F           M          A            M         J                J                A                s          0             N             D             YR
1
0. 16
0. 10
0. 11
0.21
0. 19       0. 15
18. 1
24.7
7.27
0.29
0.48
0.20
4.3
2
0. 14
0. 10
0. 14
0. 12
0. 14       4.70
14.4
16.3
7.48
0.44
0.07
0.09
3.7
3
0. 15
0. 11
0. 13
0. 10
0.38        0.09
11.1
29.9
1.88
0. 10
0.50
0. 14
3.7
4
0. 16
0. 16
0. 10
0. 10
0. 12       1.52
20.5
30.2
8.86
0.36
0.09
0. 19
5.2
5
0. 16
0. 17
0.36
0.27
0.38        0.02
4.0
30.0
6.75
0.34
0. 12
0.09
3.6
6
0.08
0.00
0.07
0. 11
0. 17
0.22
26.7
30.9
6.81
0.27
0.07
0.08
5.5
7
0. 12
0. 14
0. 16
0.36
0.31
0. 10
4.5
20.0
10.29
0.43
0.09
0. 14
3. 1
8
0.08
0.08
0.08
0. 10
0. 11
5.76
16.2
16.4
6.53
0.33
0. 17
0. 15
3.8
9
0. 12
0. 13
0.09
0. 10
0.09
0.06
20.1
30.3
6 • 8s_<
0.35
0.07
0. 13
4.9
10
0. 11
0. 12
0. 11
0. 11
0.23
0.26
9.2
16.3
6.58
0.33
0.52
0. 14
2.8
11
0. 17
0. 15
0. 16
0. 19
0. 17
0. 13
r*
«k ■ 4k
15.3
1.28
0. 14
0.30
0. 15
1.7
12
0. 16
0. 13
0. 12
0.11
0.09
0.27
14.5
44. 4
6.04
0.32
0.51
0. 14
5.6
13
0. 10
0. 10
0.24
0. 16
0.41
0.03
20.6
27. 1
3. 80
0.45
0. 15
0. 10
4. 4
14
0. 12
0. 13
0.21
0.30
0. 11
0.01
11.5
27.2
7.59
0.28
0. 18
0. 14
4.0
15
0.08
0.08
0. 10
0. 10
0.06
0. 16
21.6
10.5
3.83
0. 15
0. 17
0.22
3. 1
16
0. 18
0. 19
0. 14
0.29
0.25
0.42
16. 1
25.7
1. 13
0. 06
0. 14
0.07
3. 7
17
0. 10
0.07
0.49
0.30
0.20
0.07
12. 1
40.7
7.74
0.30
0.07
0. 11
5.2
is
0. 11
0.06
0.20
0. 13
0. 12
2.29
15.0
16.3
6.72
0. 44
0. 15
0. 11
19
0. 13
0. 10
0. 16
0. 12
3.5
0. 13
0. 10
15.8
30.3
5.75
0. 17
0. 17
0.09
4.4
20
0. 15
0.06
0. 49
0.29
0. 40
0. 17
0. 7
28.7
9.21
0.49
0.53
0. 15
3. 4
AVG           0. 13   0. 1 1      0. 18       0. 18       0.20        0.83             13. 7             25.6        6. 12            0. 30   0.23        0.13               4.0 S.D.            0.03   0.04        0. 12       0.09        0. 11        1.62              7.0                8. 7         2.53             0. 12   0. IS        0.04in i> i
•      < I I ] f- H H H H H H »■*
Q O I QO(0\|0‘UI^UK)hO’0(0>|0‘UI*WNh
B-48
Table B.8
Monthly Inflow Sequences of Subbasins - 9
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:
CHACHA
BASIN NO. :
14a
DRAINAGE AREA:
590
km' 2
x
PRECIPITATION:
1076
mm/yr
AVG RUNOFF:
330
mm/yr
RUNOFF COEFF:
30.7
7.
DISCHARGE (m' 3/S)
x
YEAR J F M A
M
J
J
A
S
0
N
D
YR
0.22
0. 15
0. 19
0.34
0.38
0.08
0.86
0. 12
17.8
22.7
17.34
0.84
0.20
0. 12
5.   1
0. 17
0. 1 1
0. 16
0.29
0.38
34.8
39.0
10.76
0.51
0.81
0.24
0. 19
0. 19
0. 12
0.21
0 • oO
24.4
49. 1
2.31
0.49
0.89
0.25
7.3
6.5
0.
15   0.09
0.
15   0.62
0.39
0.21
6.9
41.5
1.91
0.34
0. 11
0. 13
0.24
0.24
0.06
0.31
0.33
0.22
0.29
0.77
50. 1
76.0
2.5S
0. 12
0.28
0. 13
4.4
10.9
0. 19
3. 1
0. 17
0. 11
0.21
0.B3
0. 12
0. 15
0. 10
3.0
26.7
5. 14
0.56
0. 15
0.33
0.36
0.36
39.9
55.2
4.01
0. 17
0.89
0.24
0.22
0.22
0. 17
0.09
0. 16
0. 19
0.27
7.3
41.0
2.21
0.43
0.20
0.21
0.
44   0.22
0. 13
0.51
3.5
27. 1
5. 19
0.07
0.89
0.2S
8.6
4.4
3.3
0. 26
1.04
1.09
0.26
0.22
0.37
0.64
0. 41
0.22
30.4
42.2
18.90
0.63
0. 16
0.20
0.25
0.21
0.22
0.34
0. 18
0.21
0.24
6.5
64.2
6.53
0.45
0. 11
0. 19
0.34
0.26
0.27
0. 11
19. 1
46.6
19.07
0.73
0. 14
0. 19
8.0
6.6
7.3
0. 17
0. 13
0.32
0.32
0. 15
25.2
30.7
12.76
0.71
o.e7
0.25
6.  0
0. 19       0. 12       0. 11       0.09
0. 22       0. 17       0.20
0.52
0. 35 0. 1 1 33. e 49.5 12. 19 0. 47 0.89 0.27
0.71 0. 11 6.9 47.5 5.37 0. 15 0. 16 0.22
8.2
5.2
0. 18
0.20
0.26
0.    13
0.
19   0.20
0.59
21.8
34.0
7.92
0. 48
0. 10
0. 14
5.5
0.26
0 • 8^,
0.
47   0.39
0.77
15.8
■3
16.50
0.74
0.24
0.20
5. a
0. 19
0. 12
0.33
0.27
0.70
0. 48
o.es
15.3
44. 2
11.00
0.64
0.20
0. 22
0. 21
0. 15
0. 33
0. 11
34.0
28.2
16.02
0.44
0. 12
0.21
6.2
6.7
0.24
0.07
0.25
0. 11       0. 13       1.82              9. 1            31.7      14.33            0.63   0.27       0. 19
0.21         0.25         0.29         0-31         0.33         0.40      20.3          41.5          9.60          0.48          0.38          0.20
4.9
6. 2
0.03 0.29 0.21 0.19 0.18 0.41
13.5 13.4 6.00 0.22 0.33 0.05B-49
Table B.8
Monthly Inflow
Sequences of Subbasins - 10
GENERATED MONTHLY DISCHARGES (m'3/S)
BASIN NAME:       JINJER
BASIN NO.;        10a
DRAINAGE AREA:        238                kmz'2 PRECIPITATION:        1OOO          mm/yr
AVG RUNOFF:        295              mm/yr RUNOFF COEFF:         29.5           7.
DISCHARGE (m^3/S)
YEAR
J
F
M
A
M
J
J
A
s
0
N
D
YR
1
0.06
0.04
0.08
0. 10
0. 10
0.00
4.9
14.4
0.62
0.07
0. 15
0.06
1.7
A.
0.04
0.29
0.28
0.34
0.46
0.05
4.4
12.8
4.97
0. 14
0.05
0.07
2.0
3
0.07
0.05
0.06
0.06
0.00
0. 13
29.2
11.8
3 • -^/O
0. 07
0. 07
0.06
3.7
4
o.os
0. 10
0.09
0. 11
o.oe
0.09
0. 4
18.3
3.21
0. 10
0.05
0. ^5
1.9
5
0.08
0.06
0. 13
0.24
0. 19
0.24
6.9
8. 1
3.23
0.35
0.26
0.05
1.7
6
0.06
0.02
0.06
0.06
0.30
0.07
0.5
11.2
3.33
0. 10
0.03
0.34
1.3
7
0. 12
0.37
0.29
0. 10
0.08
0. 18
0. 6
19.0
4.57
0. 18
0.05
0.07
2. 1
8
0.07
0.32
0.07
0. 11
0.32
0.24
21.4
11.8
4.23
0. 16
0.06
0.02
3. 2
9
0.09
0.03
0.06
0.03
0.02
0.07
5.0
15.2
4.33
0. 19
0.26
0. 06
2. 1
10
0.09
0. 19
0.26
0.09
0.09
0.05
28. 7
17. 4
0. 60
0.04
0.05
0.27
4.0
11
0.08
0.02
0.25
0. 11
0.00
0.05
23. 1
9.S
5.05
0.25
0.23
0.05
3.2
12
0.06
0.32
0. 10
0.07
0.30
0.03
8.9
15.3
3.32
0.05
o.oe
0.04
2. 4
13
0.05
0.00
0.09
0.08
0. 10
0.20
1.7
24. 1
1.72
0.39
0.05
0.02
2.4
14
0.09
0.07
0.04
0.03
0. 06
0.03
26.0
14.7
1.54
0. 09
0.23
0.08
3. 6
13
0.08
0.06
0.04
0.23
0. 14
0. 05
1. 1
4.6
0. 17
0 • 05
0.05
0.8
16
0.04
0.05
0.03
0.03
0. 17
0.04
0.5
11.5
4.95
0.24
0. 22
0. 34
1.5
17
0. 12
0. 11
0.02
0.07
0.00
0.08
1.5
20.5
5.08
0. 14
0.24
0.36
2. 4
18
0.09
0.03
0.08
0.06
0.03
0.24
1.5
3.9
1 • 5*^
0. 16
0. 26
0.05
0. 7
19
0.04
0. 03
0.05
0.07
0.03
0. 11
10.0
S.S
3.57
0. 42
0.04
0.03
1.9
20
0.03
0.02
0.08
0.07
0.04
0. IB
8.3
9.6
4.62
0.44
0.06
0.26
2.0
AVG 0.07 0. 11 0. 11 0. 10 0.13 0. 11 9. 3 13. 1 7 0. 19 0. 13 0. 13
S.D. 0.02 0. 12 0.09 0.08 0. 13 0.08 10.3 5. 1 1.46 0. 12 0.09 0. 13B-50
—-s purpose, evaporation data contained in the 1973 Nations development Program (UNDP) technical report on 
"Investigation of Geothermal Resources for Power Development"
•ere analyzed. In this report, mean annual evaporation and evapotranspiration rates at various topographic elevations in Ethiopia are presented. From these data, the evaporation rate for reservoirs on the plateau (at an elevation of about
2,600 m) was calculated to be about 1,100 mm/yr. With a corresponding natural evapotranspiration of about 675 mm/yr, the net reservoir losses are estimated to be about
425 mm/yr.
To determine the effect of these losses on tne available mean annual power flow, the reservoir surface area at an average operating reservoir level of 2,590 m was determined for each subbasin. The losses were then calculated as a percentage of tne runoff of each subbasin.
The results of these calculations are shown in Table B.9.
It can be seen from this table that the average loss over the subbasins of the reconnaissance study amounts to 3.4%. For the main base schemes alone (i.e., Tiliku Aleltu, Jida, Gomoro and Robi), the loss is 3.9%.
The average operating surface area of the Robi reservoir is very small. This is because the surveyed riverbed level at the Robi dam is at about elevation 2,288 m, resulting in a mean reservoir depth of about 2 m. Typically, the Robi reservoir will operate during the wet season to regulate inflows and to provide the power flow during the early part of the dry season. The reservoir will then be empty during the remainder of the dry season.B-51
TABLE B.9
RESERVOIR EVAPORATION LOSSES
Drainage
Reservoir
Area at
Evaporation
Loss as
 Percent
Site            Subbasin
Area
el 2,590
Of Run
off
2
(km  )
2
(km  )
3a              Agat
92
8.0
8.6
4b             Tinishu Aleltu
37
0.5
1.4
5b             Tiliku Aleltu
458
4.0
1.0 )
) Base schemes
6c              Jida
749
36.0
6.0 
) average
) evaporation
8a              Gomoro
225
16.0
9.0 
) equals 3.9%
)
9a              Robi
437
3.0
1.0 )
2a              Weserbi
168
10.0
5.8
12c            Duber
312
1.5
0.5
14a            Chacha
590
112.0
2.7
10a            Jinjer
238
7.0
3.7
Basin Average Evaporation
3.4B-50
For this purpose, evaporation data contained in the 1973 United Nations Development Program (UNDP) technical report on "Investigation of Geothermal Resources for Power Development" were analyzed. In this report, mean annual evaporation and evapotranspiration rates at various topographic elevations in Ethiopia are presented. From these data, the evaporation 
rate for reservoirs on the plateau (at an elevation of about
2,600 m) was calculated to be about 1,100 mm/yr. With a corresponding natural evapotranspiration of about 675 mm/yr, the net reservoir losses are estimated to be about
425 mm/yr.
To determine the effect of these losses on the available mean annual power flow, the reservoir surface area at an average operating reservoir level of 2,590 m was determined for each subbasin. The losses were then calculated as a percentage of the runoff of each subbasin.
The results of these calculations are shown in Table B.9.
It can be seen from this table that the average loss over the subbasins of tne reconnaissance study amounts to 3.4%. For the main base schemes alone (i.e., Tiliku Aleltu, Jida, Gomoro and Robi), the loss is 3.9%.
The average operating surface area of the Robi reservoir is very small. This is because the surveyed riverbed level at the Robi dam is at about elevation 2,288 m, resulting in a mean reservoir depth of about 2 m. Typically, the Robi reservoir will operate during the wet season to regulate inflows and to provide the power flow during the early part of tne dry season. The reservoir will then be empty during the remainder of tne dry season.B-51
TABLE B.9
RESERVOIR EVAPORATION LOSSES
Reservoir
Area at
Evaporation
Drainage
Area
Loss
 as Per
cent
Site            Subbasin
el 2,590
Of R
unoff
2
(km  )
2
(km )
3a              Agat
92
8.0
8.6
4b              Tinishu Aleltu
37
0.5
1.4
5b             Tiliku Aleltu
458
4.0
1.0
)
)
Base schemes
6c              Jida
749
36.0
6.0
)
average
)
evaporation
8a              Gomoro
225
16.0
9.0
)
)
)
equals 3.9%
9a              Robi
437
3.0
1.0
2a              Weserbi
168
10.0
5.8
12c            Duber
312
1.5
0.5
14a            Chacha
590
112.0
2.7
10a            Jinjer
238
7.0
3.7
Basin Average Evaporation
3.4B-52
For the Duber scheme, the alternative development of a small dam in the Tiliku Duber River was considered. The resulting reservoir will only provide for weekly regulation of peak inflows during the wet season and evaporation loss will be small.
The Weserbi scheme is the only Aleltu scheme which originally contained large natural swampy areas which would be flooded out by the proposed reservoir. This swamp was not considered to be seasonal and the original swamp area was subtracted from the reservoir area to determine the incremental area
from which evaporation losses could be calculated.
It is noted that the assumed reservoir areas are derived mostly from the large-scale 1:250 000-scale mapping. In addition, the actual average operating levels of the indivi dual reservoirs can only be estimated at this stage and will need to be realistically established in future studies. It was, therefore, decided that the average basin loss of about 3.4% would not significantly affect the accuracy of the results of the reconnaissance studies. However, for the prefeasibility level studies of the Tiliku Aleltu and Jida reservoirs, the estimated evaporation losses were taken into account.
Bo - RESERVOIR REGULATION ANALYSIS
To determine the degree of regulation at each basin develop ment, the monthly inflows of the subDasins were routed through the reservoirs using the same water balance model as that used for the preliminary reconnaissance model runsB-53
(described in Section B3). For the Tiliku Aleltu and Jida subbasins, surveyed reservoir volumes were used as part of the prefeasibility level study effort. For the remaining subbasins, estimated reservoir volumes based on surveyed riverbed levels at the damsites only were used. An example
of the reservoir regulation analyses for the Jida reservoir
is shown in Table B. 10 and a summary of the relationship between reservoir volume and degree of regulation is shown in Table B.ll.
As indicated in Section B3, the results of the preliminary analyses for 100% flow regulation are shown in Table B.ll for comparison purposes. It can be derived that a significant difference exists between the calculated reservoir live
storage requirements in the preliminary and final subbasin inflow sequences. This can be caused by the larger variation in monthly flows in the synthesized prefeasibility phase reference hydrology.
B7 - FLOOD FLOW STUDIES
B7.1 - General
To permit preliminary sizing of construction diversion and flood handling facilities of the proposed Tiliku Aleltu and Jida schemes, estimates of flood peak magnitudes and shapes of inflow hydrographs were required.
Because of the scarcity of recorded flow data available in and around the Aleltu project area, and also to improve the reliability of the calculated flood peaks, a broad-basedB-54
TABLE B.10 EXAMPLE JIDA RESERVOIR REGULATION COMPUTER RUNS
STATION: BASIN 4 -JIDA MONTHLY RUNOFF in «A3/s
JAN
FEB
MR
APR
NAY
JUN
JUL
AUS
SEP
OCT
NOV
DEC
AVS
I
2
0.3
0.2
0.2
0.2
0.3
0.3
1.1
1.1
0.8
0.9
0.2
0.3
26.6
21.0
96.7
11.8
20.5
4.5
0.7
0.6
0.8
0.3
0.3
0.2
12.4
3.4
3
4
0.2
0.3
0.2
0.3
0.2
0.2
0.3
0.2
0.3
0.3
0.1
0.1
111.5 1.7
41.B
17.3
19.7
5.9
0.7
0.0
0.2
0.7
0.2
0.3
14.6
2.3
5
6
0.1
0.2
0.2
0.2
0.3
0.3
0.3
0.2
0.3
0.2
0.2
0.3
2B.7
23.2
54.7
62.8
8.1
7.4
0.3
0.5
0.6
1.0
0.3
0.3
7.8
8.1
7
8
0.3
0.3
0.4
0.3
0.3
0.1
0.2
0.2
0.2
0.2
0.2
8.1
31.9
25.8
127.9
35.1
18.2
14.5
1.3
1.2
0.8
1.0
0.3
0.2
15.2
7.3
9
10
0.2
0.3
0.2
0.3
0.3
0.9
0.3
0.5
0.3
0.5
13.1
13.0
78.5
51.3
36.6
50.1
19.6
12.3
1.3
0.4
0.1
0.1
0.2
0.1
13.0
10.8
11
12
0.2
0.2
0.2
0.0
0.3
0.1
0.2
0.1
0.2
0.0
0.3
0.2
21.9
36.1
63.9
74.1
2.9
11.2
0.5
0.7
0.3
0.1
0.3
0.2
7.6 10.3
13
14
0.2
0.2
0.3
0.1
0.4
0.3
0.3
0.3
0.3
0.1
0.2
0.5
6.7
83.0
52.4
42.6
5.0
7.3
0.4
0.3
0.1
0.2
0.2
0.3
5.6 11.2
15
16
0.3
0.3
0.2
0.2
0.2
0.9
0.5
0.4
1.2
0.3
0.4
0.2
23.3
9.1
55.1
36.4
8.3
16.6
0.5
0.4
0.2
0.3
0.9
0.1
7.6
5.4
17
16
0.2
0.2
0.1
0.2
0.2
0.1
0.2
0.1
0.3
0.7
0.1
0.9
21.9
2.8
42.2
30.7
6.1
7.4
0.6
0.1
0.2
0.2
0.2
0.3
6.0
3.6
19
20
0.2
0.3
0.1
0.2
0.4
0.2
1.1
0.2
0.7
0.2
0.2
0.0
1.0
24.0
41.6
35.1
12.0
11.8
0.6
0.6
0.2
0.9
0.2
0.2
4.9
6.1
0.2
0.2
0.3
0.4
0.4
2.2
31.5
50.4
10.9
0.6
0.4
0.3
8.2
Drainage Area: 749 ka*2
Soicific Runoft; 343.6208 aaTable B.10
Example Jida Reservoir Reaulacion Computer Runs - 2
B-55
A
CUMULATIVE STORAGE (in a 3/s)
Drift Rita: 4.08 aA3/S
JAN      FEB   MAR      APR       MAY      JUN        JUL AUG             SEP       OCT       NOV       DEC    SPILL   ST0RA6E
1
-3.8
-7.7
-11.5
-14.5
-17.6
-21.7
0.8
92.6
16.4
-3.3
-6.6
-10.4
109.8
-21.7
2
-14.2
-18.1
-21.9
-24.9
-28.1
-31.9
-15.0
-7.3
-6.9
15.6
-10.4
-14.1
-18.0
-11.2
0.0
-31.9
3
-21.9
-25.8
-29.6
-33.4
-37.2
-41.1
66.2
37.8
-3.4
-7.2
119.6
-41.1
4
-15.0
-18.8
-22.6
-26.5
-30.3
-34.3
-36.6
-23.5
-21.6
4.0
3.3
14.1
10.4
15.6
8.2
-25.7
-29.1
-32.9
0.0
-36.6
5
-36.8
-40.8
-44.5
-48.3
-52.0
-55.9
-31.3
19.3
-3.8
-7.3
-11.1
23.2
-55.9
6
-15.0
-18.8
-22.6
-26.5
-30.4
-34.2
-15.0
43.7
-3.6
-6.7
-10.4
-9.8
-9.8
47.0
-34.2
7
-14.2
-17.9
-21.7
-25.5
-29.4
-33.3
-5.5
118.4
-2.7
-6.0
132.4
-33.3
8
-13.6
-17.4
-21.4
-25.3
-29.2
-25.1
-3.4
27.7
-2.8
-5.9
38.1
-29.2
9
-13.7
-17.6
-21.3
-25.1
-28.9
-14.8
59.6
32.5
-2.8
-6.8
-10.7
107.7
-28.9
10
-14.4
-18.2
-21.4
-25.0
-28.6
-19.7
27.6
46.0
-3.7
-7.7
-11.6
81.8
-28.6
11
-15.5
-19.4
-23.2
-27.1
-31.0
-34.8
-17.0
42.9
-1.2
7.1
0.9
3.2
4.2
12.5
2.0
-4.8
-8.7
-12.5
42.9
-34.8
12
-16.3
-20.4
-24.4
-28.4
-32.5
-36.3
-4.3
65.7
-3.4
-7.3
-11.2
72.9
-36.3
13
-15.0
-18.8
-22.5
-26.3
-30.0
-33.8
-31.2
17.1
-3.6
-7.6
-11.4
18.0
-33.8
14
-15.3
-19.3
-23.0
-26.8
-30.8
-34.4
44.5
38.5
-3.8
-7.7
-11.6
86.2
-34.4
15
-15.4
-19.2
-23.1
-26.7
-29.6
-33.2
-14.0
37.0
-3.5
-7.4
-10.7
41.2
-33.2
16
-14.5
-18.4
-21.5
-25.2
-29.0
-32.9
-27.8
4.5
-3.7
-7.5
-11.4
17.0
-32.9
17
-15.3
-19.3
-23.1
-27.0
-30.9
-34.8
-16.9
21.2
-3.5
-7.4
-11.3
23.2
-34.8
18
-15.1
-19.0
-22.9
-26.9
-30.3
-33.5
-34.8
-8.1
-4.8
4.1
7.7
-8.8
-12.7
-16.5
0.0
-34.8
19
-20.4
-24.4
-28.1
-31.1
-34.4
-38.3
-41.3
-3.8
-3.5
-7.3
-11.2
4.1
-41.3
20
-15.0
-18.9
-22.8
-26.7
-30.6
-34.7
-14.7
16.3
-3.5
-6.6
-10.5
24.0
-34.7
A
CUMULATIVE STORAGE (in a 3/«)
Drift Rita: 4.89 aA3/S
JAN       FEB      MAR      APR      MAY       JUN       JUL       AU6       SEP       OCT       NOV       OEC     SPILL ST0RA6E
1
-4.6
-9.3
-13.9
-17.7
-21.9
-26.6
-4.9
86.9
15.6
-4.2
-8.2
-12.9
102.5
-26.6
2
-17.5
-22.2
-26.8
-30.7
-34.6
-39.2
-23.2
-16.3
-16.7
-21.0
-25.6
-30.2
0.0
-39.2
3
-34.9
-39.6
-44.3
-48.9
-53.5
-58.3
48.3
37.0
14.8
-4.2
-8.9
-13.6
100.0
-58.3
4
-18.2
-22.8
-27.5
-32.2
-36.8
-41.6
-44.8
-32.4
-31.4
-36.3
-40.5
-45.1
0.0
-45.1
5
-49.9
-54.6
-59.2
-63.8
-68.3
-73.1
-49.2
0.5
3.2
-4.6
-8.9
-13.5
3.7
-73.1
6
-18.2
-22.9
-27.5
-32.2
-36.9
-41.5
-23.2
34.8
2.5
-4.4
-8.3
-12.9
37.2
-41.5
7
-17.4
-22.0
-26.6
-31.2
-35.9
-40.6
-13.6
109.4
13.3
-3.6
-7.7
-12.3
122.6
-40.6
8
-16.9
-21.5
-26.3
-31.0
-35.7
-32.4
-11.6
18.7
9.6
-3.7
-7.6
-12.2
28.3
-35.7
9
-16.9
-21.6
-26.2
-30.8
-35.4
-22.1
51.4
31.7
14.7
-3.6
-8.4
-13.1
97.9
-35.4
10
-17.7
-22.3
-26.3
-30.7
-35.1
-27.1
19.4
45.2
7.4
-4.5
-9.3
-14.1
72.0
-35.1
11
-18.8
-23.5
-28.1
-32.8
-37.5
-42.2
-25.1
33.9
-2.0
-6.5
-11.1
-15.7
33.9
-42.2
12
-20.4
-25.3
-30.1
-34.9
-39.8
-44.4
-13.3
55.9
6.3
-4.2
-8.9
-13.6
62.3
-44.4
13
-18.3
-22.9
-27.4
-32.0
-36.5
-41.2
-39.3
8.2
0.1
-4.5
-9.2
-13.9
8.2
-41.2
14
-18.6
-23.3
-27.9
-32.5
-37.3
-41.7
3o.3
37.7
2.4
-4.6
-9.4
-14.0
76.4
-41.7
15
-18.6
-23.3
-28.0
-32.4
-36.1
-40.6
-22.2
28.1
3.4
-4.4
-9.0
-13.1
31.5
-40.6
lo
-17.8
-22.4
-26.4
-30.9
-35.5
-40.3
-36.0
-4.5
7.2
-4.5
-9.1
-13.9
7.2
-40.3
17
-18.0
-23.4
-28.0
-32.7
-37.4
-42.1
-25.1
12.2
1.2
-4.3
-9.0
-13.7
13.4
-42.1
IB
-18.4
-23.0
-27.8
-32.6
-36.8
-40.8
-42.9
-17.1
-14.6
-19.4
-24.1
-28.7
0.0
-42.9
19
-33.5
-38.2
-42.8
-46.0
-50.7
-55.4
-59.2
-22.6
-15.5
-19.8
-24.4
-29.2
0.0
-59.2
20
-33.7
-38.4
-43.1
-47.9
-52.0
-57.5
-38.4
-8.2
-1.3
-5.6
-9.5
-14.2
0.0
-57.5B-54
TABLE B.10 EXAMPLE JIDA RESERVOIR REGULATION COMPUTER RUNS
STATION: BASIN 4 -JIDA MONTHLY RUNOFF in r3/i
JAN
FEB
WAR
APR
HAY
JUN
JUL
AU6
SEP
OCT
NOV
DEC
AV6
I
2
0.3
0.2
0.2
0.2
0.3
0.3
1.1
1.1
0.8
0.9
0.2
0.3
26.4
21.0
96.7
11.8
20.5
4.5
0.7
0.6
0.8
0.3
0.3
0.2
12.4
3.4
3
4
0.2
0.3
0.2
0.3
0.2
0.2
0.3
0.2
0.3
0.3
0.1
0.1
111.5 1.7
41.8
17.3
19.7
5.9
0.7
0.0
0.2
0.7
0.2
0.3
14.6 2.3
5
6
0.1
0.2
0.2
0.2
0.3
0.3
0.3
0.2
0.3
0.2
0.2
0.3
2B.7
23.2
54.7
62.8
8.1
7.4
0.3
0.5
0.6
1.0
0.3
0.3
7.8
8.1
7
8
0.3
0.3
0.4
0.3
0.3
0.1
0.2
0.2
0.2
0.2
0.2
8.1
31.9
25.8
127.9
35.1
18.2
14.5
1.3
1.2
0.8
1.0
9
10
0.3
0.2
15.2
7.3
0.2
0.3
0.2
0.3
0.3
0.9
0.3
0.5
0.3
0.5
ia.1
13.0
78.5
51.3
36.6
50.1
19.6
12.3
1.3
0.4
0.1
0.1
0.2
0.1
11
12
0.2
0.2
13.0
10.8
0.2
0.0
0.3
0.1
0.2
0.1
0.2
0.0
0.3
0.2
21.9
36.1
63.9
74.1
2.9
11.2
0.5
0.7
0.3
0.1
13
14
0.2
0.2
0.3
0.2
0.3
0.1
0.4
0.3
7.6 10.3
0.3
0.3
0.3
0.1
0.2
0.5
6.7
B3.0
52.4
42.6
5.0
7.3
0.4
0.3
15
16
0.3
0.3
0.1
0.2
0.2
0.2
0.2
0.3
0.2
0.9
0.5
0.4
5.6 11.2
1.2
0.3
0.4
0.2
23.3
9.1
55.1
36.4
8.3
16.6
0.5
0.4
17
18
19
20
0.2
0.2
0.2
0.1
0.2
0.1
0.2
0.3
0.8
0.1
0.2
0.1
0.4
0.2
0.1
1.1
7.6
5.4
0.3
0.7
0.7
0.1
0.9
0.2
21.9
2.8
1.0
42.2
30.7
41.6
6.1
7.4
12.0
0.3
0.6
0.1
0.6
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.2
0.3
0.2
6.0
3.6
4.9
0.0
24.0
35.1
50.4
11.8
0.6
0.9
0.2
6.1
0.2
0.2
0.3
0.4
0.4
2.2
31.5
10.9
0.6
0.4
0.3
8.2
Drainage Area: 749 ka*2
Specific Runoff: 343.6208 uTable B.10
Example Jida Reservoir Regulation Computer Runs - 2
CUMULATIVE STORAGE (in i*3/sl Draft Rati: 4.08 eA3/S
JAN
FEB
MAR
APR
MAY
JUN
JUL
AU6
SEP
OCT
NOV
DEC
SPILL
ST0RA6E
1
-3.8
-7.7
-11.5
-14.5
-17.8
-21.7
0.8
92.6
16.4
-3.3
-6.6
-10.4
109.8
-21.7
2
-14.2
-18.1
-21.9
-24.9
-28.1
-31.9
-15.0
-7.3
-6.9
-10.4
-14.1
-18.0
0.0
-31.9
3
-21.9
-25.8
-29.6
-33.4
-37.2
-41.1
66.2
37.8
15.6
-3.4
-7.2
-11.2
119.6
-41.1
4
-15.0
-18.1
-22.6
-26.5
-30.3
-34.3
-36.6
-23.5
-21.6
-25.7
-29.1
-32.9
0.0
-36.6
5
-36.8
-40.8
-44.5
-48.3
-52.0
-55.9
-31.3
19.3
4.0
-3.8
-7.3
-11.1
23.2
-55.9
6
-15.0
-18.8
-22.6
-26.5
-30.4
-34.2
-15.0
43.7
3.3
-3.6
-6.7
-10.4
47.0
-34.2
7
-14.2
-17.9
-21.7
-25.5
-29.4
-33.3
-5.5
118.4
14.1
-2.7
-6.0
-9.8
132.4
-33.3
8
-13.6
-17.4
-21.4
-25.3
-29.2
-25.1
-3.4
27.7
10.4
-2.8
-5.9
-9.8
38.1
-29.2
9
-13.7
-17.6
-21.3
-25.1
-28.9
-14.8
59.6
32.5
15.6
-2.8
-6.8
-10.7
107.7
-28.9
10
-14.4
-18.2
-21.4
-25.0
-28.6
-19.7
27.6
46.0
8.2
-3.7
-7.7
-11.6
81.8
-28.6
1!
-15.5
-19.4
-23.2
-27.1
-31.0
-34.8
-17.0
42.9
-1.2
-4.8
-8.7
-12.5
42.9
-34.8
12
-16.3
-20.4
-24.4
-28.4
-32.5
-36.3
-4.3
65.7
7.1
-3.4
-7.3
-11.2
72.9
-36.3
13
-15.0
-18.8
-22.5
-26.3
-30.0
-33.8
-31.2
17.1
0.9
-3.6
-7.6
-11.4
18.0
-33.8
14
-15.3
-19.3
-23.0
-26.8
-30.8
-34.4
44.5
38.5
3.2
-3.8
-7.7
-11.6
86.2
-34.4
13
-15.4
-19.2
-23.1
-26.7
-29.6
-33.2
-14.0
37.0
4.2
-3.5
-7.4
-10.7
41.2
-33.2
16
-14.5
-18.4
-21.5
-25.2
-29.0
-32.9
-27.8
4.5
12.5
-3.7
-7.5
-11.4
17.0
-32.9
17
-15.3
-19.3
-23.1
-27.0
-30.9
-34.8
-16.9
21.2
2.0
-3.5
-7.4
-11.3
23.2
-34.8
18
-15.1
-19.0
-22.9
-26.9
-30.3
-33.5
-34.8
-8.1
-4.8
-8.8
-12.7
-16.5
0.0
-34.8
19
-20.4
-24.4
-28.1
-31.1
-34.4
-38.3
-41.3
-3.8
4.1
-3.5
-7.3
-11.2
4.1
-41.3
20
-15.0
-18.9
-22.8
-26.7
-30.6
-34.7
-14.7
16.3
7.7
-3.5
-6.6
-10.5
24.0
-34.7
A
CUMULATIVE STORAGE (in « 3/s) Draft Rate: 4.89 iA3/S
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUS
SEP
OCT
NOV
DEC
SPILL
STORAGE
1
-4.6
-9.3
-13.9
-17.7
-21.9
-26.6
-4.9
86.9
15.6
-4.2
-8.2
-12.9
102.5
-26.6
2
-17.5
-22.2
-26.8
-30.7
-34.6
-39.2
-23.2
-16.3
-16.7
-21.0
-25.6
-30.2
0.0
-39.2
3
-34.9
-39.6
-44.3
-48.9
-53.5
-58.3
48.3
37.0
14.B
-4.2
-8.9
-13.6
100.0
-58.3
4
-18.2
-22.8
-27.5
-32.2
-36.8
-41.6
-44.8
-32.4
-31.4
-36.3
-40.5
-45.1
-54.6
0.0
5
-49.9
-59.2
-63. B
-45.1
-68.3
-73.1
-49.2
0.5
3.2
-4.6
-8.9
-13.5
3.7
6
-18.2
-22.9
-27.5
-32.2
-36.9
-73.1
-41.5
-23.2
34.8
2.5
-4.4
-8.3
-12.9
7
-17.4
-22.0
-26.6
-31.2
-35.9
37.2
-41.5
-40.6
-13.6
109.4
13.3
-3.6
-7.7
-16.9
-21.5
-26.3
-12.3
8
-31.0
-35.7
122.6
-40.6
-32.4
-11.0
18.7
9.6
-3.7
-16.9
-7.6
9
-21.6
-26.2
-30.8
-12.2
-35.4
28.3
-35.7
-22.1
51.4
31.7
14.7
-3.0
-8.4
-13.1
97.9
10
-17.7
-22.3
-26.3
-30.7
-35.1
-35.4
-27.1
19.4
45.2
7.4
-4.5
-9.3
-14.1
72.0
11
-18.8
-23.5
-28.1
-32.8
-37.5
-35.1
-42.2
-25.1
33.9
-2.0
-6.5
12
-20.4
-30.1
-11.1
-25.3
-34.9
-15.7
33.9
-39.8
-44.4
-42.2
-13.3
55.9
6.3
-4.2
-8.9
13
-18.3
-22.9
-27.4
-32.0
-13.6
-36.5
62.3
-44.4
-41.2
-39.3
B.2
0.1
-4.5
-27.9
-9.2
-13.9
14
-18.6
-23.3
-32.5
-37.3
8.2
-41.7
-41.2
36.3
37.7
2.4
-4.6
-9.4
-14.0
15
-18.6
-23.3
-28.0
-32.4
-36.1
76.4
-41.7
-40.6
-22.2
28.1
3.4
-4.4
-26.4
-9.0
-13.1
16
-17.8
-22.4
-30.9
-35.5
31.5
-40.3
-40.6
-36.0
-4.5
7.2
-4.5
-9.1
-13.9
17
-18.6
-23.4
-28.0
-32.7
-37.4
7.2
-42.1
-40.3
-25.1
12.2
1.2
-4.3
-18.4
-27.8
-9.0
-13.7
18
-23.0
-32.6
-36.8
13.4
-40.8
-42.9
-42.1
-17.1
-14.6
-19.4
-24.1
-42.8
-28.7
19
-33.5
-38.2
-4b.6
-50.7
-55.4
0.0
-42.9
-59.2
-22.6
-15.5
-19.8
-38.4
-47.9
-24.4
-29.2
20
-33.7
-43.1
-52.0
0.0
-57.5
-38.4
-59 2
-8.2
-1.3
-5.6
-9.5
-14.2
0.0
-57.5Table B.10
Example Jida Reservoir Regulation Computer Runs - 3
CUMULATIVE STORAGE (in «*3/s) Drift Rati: 3.71 i'3/S
B-56
JAN
FEB
MAR
APR
MAY
JUN
JUL
AU6
SEP
OCT
NOV
DEC
SPILL
STORAGE
I
-5.5
-10.9
-16.4
-21.0
-25.9
-31.5
-10.6
80.4
14.7
-5.0
-9.9
-15.3
95.1
-31.5
2
-20.8
-26.2
-31.7
-36.4
-41.2
-46.6
-31.3
-25.2
-26.4
-31.6
-37.0
-42.5
0.0
-46.6
3
-48.0
-53.5
-59.0
-64.4
-69.8
-75.4
30.4
36.1
14.0
-5.0
-10.5
-16.0
80.5
-75.4
4
-21.5
-26.9
-32.4
-37.9
-43.3
-49.0
-53.0
-41.4
-41.2
-46.9
-51.9
-57.4
0.0
-57.4
5
-62.9
-68.5
-73.9
-79.2
-84.6
-90.2
-67.2
-18.2
-15.9
-21.3
-26.4
-31.9
0.0
-90.2
6
-37.4
-42.9
-48.3
-53.8
-59.4
-64.7
-47.2
9.9
1.7
-5.2
-9.9
-15.3
11.6
-64.7
7
-20.7
-26.1
-31.5
-36.9
-42.4
-48.0
-21.8
100.4
12.4
-4.4
-9.3
-14.7
112.9
-48.0
a
-20.1
-25.6
-31.2
-36.7
-42.2
-39.8
-19.7
9.7
8.8
-4.5
-9.2
-14.7
18.5
-42.2
9
-20.2
-25.7
-31.1
-36.5
-41.9
-29.5
43.3
30.9
13.9
-4.4
-10.0
-15.5
88.1
-41.9
10
-21.0
-26.3
-31.1
-36.4
-41.7
-34.4
11.2
44.4
6.6
-5.4
-10.9
-16.5
62.2
-41.7
n
-22.0
-27.6
-33.0
-38.5
-44.0
-49.5
-33.3
24.9
-2.8
-8.1
-13.5
-19.0
24.9
-49.5
12
-24.5
-30.2
-35.8
-41.4
-47.1
-52.6
-22.2
46.2
5.5
-5.0
-10.6
-16.1
51.7
-52.6
13
-21.5
-27.0
-32.2
-37.7
-43.1
-48.5
-47.5
-0.8
-1.5
-6.8
-12.4
-17.9
0.0
-48.5
14
-23.4
-29.0
-34.3
-39.8
-45.4
-50.6
26.6
36.9
1.6
-5.4
-11.0
-16.4
65.1
-50.6
15
-21.9
-27.4
-32.9
-38.1
-42.6
-47.9
-30.3
19.1
2.6
-5.2
-10.6
-15.6
21.7
-47.9
16
-21.0
-26.5
-31.3
-36.6
-42.1
-47.6
-44.1
-13.4
-2.6
-7.9
-13.3
-18.9
0.0
-47.6
17
-24.4
-30.0
-35.5
-41.0
-46.5
-52.1
-35.8
0.7
0.4
-5.1
-10.7
-16.2
1.1
-52.1
IS
-21.7
-27.1
-32.7
-38.3
-43.4
-48.2
-51.1
-26.1
-24.4
-30.0
-35.5
-41.0
0.0
-51.1
19
-46.5
-52.1
-57.4
-62.1
-67.0
-72.5
-77.2
-41.3
-35.0
-40.1
-45.6
-51.2
0.0
-77.2
20
-56.6
-62.1
-67.6
-73.2
-78.7
-84.4
-66.1
-36.7
-30.6
-35.7
-40.5
-46.0
0.0
-84.4
A
CUMULATIVE STORAGE (in i 3/«) Drift Rati: 6.52 i'3/S
JAN
FEB
MAR
APR
NAY
JUN
JUL
AU6
SEP
OCT
NOV
DEC
SPILL
ST0RA6E
I
-6.3
-12.6
-18.8
-24.3
-30.0
-36.4
-16.3
73.9
13.9
-5.8
-11.5
-17.7
87.B
-36.4
2
-24.0
-30.3
-36.6
-42.1
-47.7
-53.9
-39.5
-34.2
-36.2
-42.2
-48.4
-54.7
0.0
-54.7
3
-61.0
-67.4
-73.7
-79.9
-86.1
-92.5
12.4
35.3
13.2
-5.8
-12.1
-18.5
60.9
-92.5
4
-24.7
-31.0
-37.3
-43.6
-49.8
-56.3
-61.1
-50.4
-51.0
-57.5
-63.3
-69.6
0.0
-69.6
5
-76.0
-82.4
-88.6
-94.7
-101.0
-107.3
-85.1
-37.0
-35.5
-41.7
-47.6
-53.9
0.0
-107.3
6
-e0.2
-66.6
-72.8
-79.1
-85.5
-91.6
-74.9
-18.7
-17.8
-23.8
-29.4
-35.6
0.0
-91.6
7
-41.8
-47.9
-54.2
-60.5
-66.7
-73.1
-47.7
73.6
11.6
-5.2
-10.9
-17.2
85.3
-73.1
8
-23.4
-29.6
-36.0
-42.4
-48.7
-47.1
-27.9
0.7
8.0
-5.3
-10.8
-17.1
8.7
9
-23.4
-29.8
-36.0
-42.2
-48.4
-36.8
35.1
30.1
-48.7
13.1
-5.3
-11.7
-18.0
78.3
-*8.4
10
-24.2
-30.4
-36.0
-42.1
-48.2
-41.7
3.1
43.6
5.7
-6.2
-12.6
-50.6
-56.8
-41.4
-19.0
52.4
-48.2
11
-25.3
-31.6
-37.9
-44.2
16.0
-3.7
-9.7
-16.0
-22.3
16.0
-56.8
12
-28.6
-35.1
-41.5
-47.9
-54.5
-60.8
-31.2
36.4
4.7
-5.8
-12.2
-18.5
41.1
U-6V0i .o8
13
-24.8
-31.1
-37.1
-43.4
-49.6
-55.9
-55.6
-9.8
-11.3
-17.4
-23.8
-30.1
14
-36.4
-42.8
-49.0
-55.3
-61.7
-67.8
8.7
36.1
0.0
0.7
w-w55. 79
-6.3
-12.6
-18.9
45.5
15
-25.2
-31.5
-37.7
-43.8
-49.1
-55.2
-38.5
10.1
1.8
U-6r7• fQi
-6.0
-12.3
-36.2
-42.3
-48.6
-54.9
-52.3
-18.0
16
-24.3
-30.6
-22.4
11 9
-55 7
-12.4
-18.5
-24.7
-56.5
-62.8
-68.4
-69.2
-74.0
-53.8
-77.7
-18.1
-53.6
-31.1
17
18
19
20
-37.5
-43.4
-43.9
-50.2
-56.1
-90.6
-110.6
V0. Vfl
-49.7
-62.5
-78.1
-84.5
-96.1
-101.9
-113.6
-78.6
-97.9
-104.2
-117.0
-123.3
-108.2
-129.8
-112.3
-83.8
-18.5
-52.7
-73.1
-78.5
-24.5
-30.8
-37.1
-59.1
-65.5
-71.7
-79.1
-69.2
-77.7
-85.3
-91.7
-84.4
0.0
0.0
0.0
0.0
-113.6
-90.0
-96.3
-129.8Table B.10
Example Jida Reservoir Regulation Computer Runs - 4
CUMULATIVE STORAGE (in a 3/s) Drift Rati: 7.34 aA3/S
B-57
A
1
JAN
-7.1
FEB
-14.2
MAR
-21.3
APR
-27.5
MAY
-34,1
JUN
-41.3
JUL
-22.0
AU6        SEP       OCT       NOV       DEC      SPILL    ST0RA6E
2 -27.3 -34.4 -41.5 -47.8 -54.2 -61.3 -47.6
3 -74.1 -81.2 -88.4 -95.4 -102.4 -109.7 -5.5
4 -28.0 -35.1 -42.2 -49.3 -56.4 -63.7 -69.3
5 -89.0 -96.2 -103.2 -110.2 -117.3 -124.4 -103.1
-13.1 -20.2 80.5 -41.3
-59.8 -66.9 0.0 -66.9
-13.8       -20.9        41.3
-109.7
-74.8 -81.8 0.0
-68.8 -75.9 0.0
-81.8
-124.4
6       -83.1      -90.2
7       -74.4      -81.4
S       -26.7      -33.7
9       -27.8      -35.0
10       -27.5      -34.5
11       -28.5      -35.7
12       -32.7      -40.0
13       -28.1      -35.1
14       -49.5      -56.7
15 -28.5 -35.6
16 -27.5 -34.7
17 -50.5 -57.8
IB -66.3 -73.4
19 -110.7 -117.9
20 -140.3 -147.5
-97.3 -104.4 -111.6 -118.6 -102.7 -88.4 -95.5 -102.6 -109.8 -85.3 -40.9 -48.1 -55.3 -54.5 -36.0 -42.0 -49.0 -56.0 -45.2 25.9 -40.9 -47.8 -54.7 -49.1 -5.1 -42.8 -49.9 -57.1 -64.2 -49.6 -47.2 -54.5 -61.8 -68.9 -40.2 -42.0 -49.1 -56.1 -63.2 -63.8 -63.7 -70.8 -78.0 -84.9 -9.2 -42.7 -49.6 -55.8 -62.7 -46.7 -41.1 -48.1 -55.1 -62.3 -60.5 -64.9 -72.0 -79.1 -86.3 -71.7 -80.6 -87.8 -94.5 -100.9 -105.5
-124.9 -131.1 -137.8 -144.9 -151.2 -154.6 -161.8 -169.0 -176.3 -159.6
67.3        13.1        -6.6 -43.2       -46.0       -52.8
29.0        12.3        -6.7 -59.4       -60.8       -68.1 -55.8       -55.1      -62.1
-47.2       -47.2       -54.0
35.3        10.8        -6.0
-8.2         -1.1        -7.2
29.3        12.3        -6.1
37.7          4.9        -7.0
7.0        -4.5       -11.4
26.6          3.9        -6.6
-18.8      -21.1       -28.0
26.0        -0.1        -7.2
1.1          0.9        -6.8
-31.4 -22.2 -29.1 -36.9 -38.1 -44.8 -82.1 -82.1 -89.3
-60.4       -67.4          0.0
-118.6
-12.6 -19.6 46.1
-13.5       -20.7          0.0
-13.3       -20.4        67.4
-14.2       -21.4        42.6
-18.4 -25.5 7.0
-13.8 -21.0 30.4
-35.2       -42.3          0.0
-14.3       -21.4        26.0
-13.9       -20.5          2.0
-36.2       -43.4          0.0
-52.0       -59.2          0.0
-96.4     -103.5          0.0
-109.8
-55.3
-56.0
-54.7
-64.2
-68.9
-63.8
-84.9
-62.7
-62.3
-86.3
-105.5
-116.9     -112.3    -119.0
-126.1     -133.3          0.0
-151.2
-131.9    -127.4    -134.2
-140.6     -147.7          0.0
-176.3
A
CUMULATIVE ST0RA6E (in a 3/s) Drift Rita: 8.16 aA3/S
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUS
SEP
OCT
NOV
-7.9
-15.8
-23.7
DEC
-30.8
SPILL
1
ST0RA6E
-38.2
-46.2
-27.7
60.8
12.3
-7.4
-14.8
-22.6
2
-30.6
-38.5
-46.4
-53.5
73.1
-46.2
-60.7
-68.6
-55.8
-52.2
-55.8
-63.4
-71.2
3
-87.1
-95.1
-103.0
-110.9
-79.2
0.0
-118.7
-79.2
-126.8
-23.5
10.2
11.5
-7.5
-15.4
4
-31.3
-39.1
-47.1
-23.4
-55.0
-62.9
21.S
-126.8
-71.0
-77.4
-68.3
-70.6
-78.7
-86.2
-94.1
5
-102.1
-110.1
-117.9
-125.7
0.0
-94.1
-133.6
-141.6
-121.0
-74.5
-74.6
-82.5
-90.0
-97.9
6
-105.9
-113.9
-121.7
-129.7
0.0
-137.6
-141.6
-145.5
-130.4
-75.8
-76.5
-84.2
-91.3
7
-107.0
-114.8
-122.7
-130.6
-99.2
0.0
-138.5
-145.5
-146.5
-122.8
-3.0
7.0
-6.8
-14.2
-22.1
8
-29.9
-37.8
-45.8
-53.8
-61.8
7.0
-146.5
-61.8
-44.2
-17.2
-10.9
-17.8
-46.8
-56.7
-25.0
-32.9
9
-40.8
-64.5
-72.4
0.0
-62.4
-61.8
7.9
28.4
11.5
-6.9
-14.9
-22.9
10
-30.7
-38.6
-45.8
-53.5
47.9
-61.2
-72.4
-56.4
-13.2
28.7
4.1
-7.8
11
-47.7
-15.8
-31.8
-39,8
-55.6
-23.9
-63.6
J2.8
-61.2
-71.5
-57.7
-2.0
-7.3
-15.0
-22.9
12
-38.7
-46.8
-54.9
-63.0
-71.1
-30.8
0.0
-79.0
-71.5
-51.1
14.8
3.1
-7.4
-46.9
-15.5
-23.4
17.9
13
-31.3
-39.2
-54.8
-62.6
-70.5
-79.0
-72.0
-27.7
-30.9
-38.6
-78.4
-46.6
14
-62.5
-70.6
-86.3
-54.6
-94.3
0.0
-72.0
-102.0
-27.2
7.3
-0.9
-8.8
-16.8
15
-32.6
-40.5
-48.4
-56.1
-24.7
-63.1
7.3
-70.8
-102.0
-55.7
-8.7
-8.6
-16.2
-24.1
16
-39.4
-47.3
-54.6
-62.3
-31.5
0.0
-70.2
-70.8
-78.2
-77.2
-48.9
-40.5
-48.3
-56.2
-64.2
0.0
17
-72.2
-80.2
-88.1
-96.1
-104.0
-112.0
-78.2
-98.2
-64.2
-66.2
-73.8
-81.8
18
-97.7
-105.o
-113.6
-121.7
-89.8
-129.2
0.0
-136.4
-112.0
-141.8
-119.2
-120.0
-128.1
-136.0
-143.9
19
-151.9
-159.9
-167.7
-174.8
-182.2
0.0
-190.1
-143.9
-197.3
-163.8
-160.0
-167.6
-175.5
-183.5
20
-191.3
-199.3
-207.3
-215.3
-223.2
0.0
-231.4
-197.3
-215.5
-188.6
-185.0
-192.5
-199.7
-207.7
0.0
-231.4Table B.10
Example Jida Reservoir Regulation Computer Runs - 3
CUMULATIVE STORAGE (in a 3/s)
Drift Rite:          5.71 eA3/S
B-56
A
1
2
3
4
5
a
7
8
9
10
11
12
13
15
16
17
18
19
20
JAN        FEB        MAR       APR        NAY        JUN        JUL        AU6       SEP       OCT       NOV       DEC     SPILL    STQRA6E -5.5        -10.9       -16.4       -21.0       -25.9       -31.5       -10.6        80.4        14.7        -5.0        -9.9      -15.3        95.1    "31 • 5
■it
-20. B       -26.2       -31.7       -36.4       -41.2       -46.6       -31.3       -25.2      -26.4      -31.6      -37.0      -42.5
0.0     ”46«6
-48.0        -53.5       -59.0       -64.4       -69.8       -75.4        30.4        36.1        14.0        -5.0      -10.5      -16.0       80* 5     -75. 4
-21.5        -26.9       -32.4       -37.9       -43.3       -49.0       -53.0       -41.4      -41.2      -46.9      -51.9      -57.4          0.0       -57.4
If 1
-62.9        -68.5       -73.9       -79.2       -84.6       -90.2       -67.2       -18.2      -15.9      -21.3      -26.4      -31.9          0.0
BA A
-90.2
-37.4        -42.9       -48.3       -53.8       -59.4       -64.7       -47.2          9.9          1.7        -5.2        -9.9      -15.3        11.6       -64.7
-20.7        -26.1       -31.5       -36.9       -42.4       -48.0       -21.8      100.4        12.4        -4.4        -9.3      -14.7      112.9      -4B.0
-20.1        -25.6       -31.2       -36.7       -42.2       -39.8       -19.7          9.7          8.8        -4.5        -9.2      -14.7        18.5      -42.2
-20.2        -25.7       -31.1       -36.5       -41.9       -29.5        43.3        30.9        13.9        -4.4      -10.0      -15.5        88.1       -41.9
-21.0 -26.3 -31.1 -36.4 -41.7 -34.4 11.2 44.4 6.6 -5.4 -10.9 -16.5 62.2 -41.7 -22.0 -27.6 -33.0 -38.5 -44.0 -49.5 -33.3 24.9 -2.8 -8.1 -13.5 -19.0 24.9 -49.5 -24.5 -30.2 -35.8 -41.4 -47.1 -52.6 -22.2 46.2 5.5 -5.0 -10.6 -16.1 51.7 -52.6 -21.5 -27.0 -32.2 -37.7 -43.1 -48.5 -47.5 -0.8 -1.5 -6.8 -12.4 -17.9 0.0 -40.5
14 -23.4 -29.0 -34.3 -39.8 -45.4 -50.6 26.o 36.9 1.6 -5.4 -11.0 -16.4 65.1 -50.6
-21.9        -27.4       -32.9       -38.1       -42.6       -47.9       -30.3        19.1          2.6        -5.2      -10.a      -15.6        21.7      -47.9
-21.0        -26.5       -31.3       -36.6       -42.1       -47.6       -44.1       -13.4        -2.6        -7.9      -13.3      -1B.9          0.0      -47.6
-24.4        -30.0       -35.5       -41.0       -46.5       -52.1       -35.8          0.7          0.4        -5.1      -10.7      -16.2        1.1     -52.1
-21.7        -27.1       -32.7       -38.3       -43.4       -48.2       -51.1      -26.1       -24.4      -30.0      -35.5      -41.0          0.0      -51.1
-46.5        -52.1       -57.4       -62.1       -67.0       -72.5       -77.2      -41.3      -35.0      -40.1      -45.6      -51.2          0.0      -77.2
-56.6       -62.1       -67.6       -73.2       -78.7       -84.4       -66.1       -36.7      -30.6      -35.7      -40.5      -46.0          0.0       -84.4
A
CUMULATIVE ST0RA6E (in e 3/s)
Drift Rite: 6.52 e'3/S
JAN FEB MAR APR        MAY       JUN        JUL        AU6      SEP        OCT       NOV       DEC     SPILL    STORAGE
1
-a.3
-12.6
-18.8
-24.3
-30.0
-36.4
-16.3
73.9
13.9
-5.8
-11.5
-17.7
87.8
-36.4
2
-24.0
-30.3
-36.6
-42.1
-47.7
-53.9
-39.5
-34.2
-36.2
-42.2
-48.4
-54.7
0.0
-54.7
3
-61.0
-67.4
-73.7
-79.9
-86.1
-92.5
12.4
35.3
13.2
-5.8
-12.1
-18.5
60.9
-92.5
4
-24.7
-31.0
-37.3
-43.6
-49.8
-56.3
-61.1
-50.4
-51.0
-57.5
-63.3
-69.6
0.0
-69.6
5
-76.0
-82.4
-88.6
-94.7
-101.0
-107.3
-85.1
-37.0
-35.5
-41.7
-47.6
-53.9
0.0
-107.3
6
-60.2
-66.6
-72.8
-79.1
-85.5
-91.6
-74.9
-18.7
-17.8
-23.8
-29.4
-35.6
0.0
-91.6
7
-41.8
-47.9
-54.2
-60.5
-66.7
-73.1
-47.7
73.6
11.6
-5.2
-10.9
-17.2
85.3
-73.1
8
-23.4
-29.6
-36.0
-42.4
-48.7
-47.1
-27.9
0.7
8.0
-5.3
-10.8
-17.1
8.7
-48.7
9
-23.4
-29.8
-36.0
-42.2
-48.4
-36.8
35.1
30.1
13.1
-5.3
-11.7
-18.0
78.3
-48.4
10
-24.2
-30.4
-36.0
-42.1
-48.2
-41.7
3.1
43.6
5.7
-6.2
-12.6
-19.0
52.4
-48.2
11
-25.3
-31.6
-37.9
-44.2
-50.6
-56.8
-41.4
16.0
-3.7
-9.7
-16.0
-22.3
16.0
-56.8
12
-2B.6
-35.1
-41.5
-47.9
-54.5
-60.8
-31.2
36.4
4.7
-5.8
-12.2
-18.5
41.1
-60.8
13
-24.e
-31.1
-37.1
-43.4
-49.6
-55.9
-55.6
-9.8
-11.3
-17.4
-23.8
-30.1
0.0
-55.9
14
-36.4
-42.8
-49,0
-55.3
-61.7
-67.8
B.7
36.1
0.7
-6.3
-12.6
-18.9
45.5
-67.8
15
-25.2
-31.5
-37.7
-43.8
-49.1
-55.2
-38.5
10.1
1.8
-6.0
-12.3
-18.0
11.9
-55.2
16
-24.3
-30.6
-36.2
-42.3
-48.6
-54.9
-52.3
-22.4
-12.4
-18.5
-24.7
-31.1
0.0
-54.9
17
-37.5
-43.9
-50.2
-56.5
-.2.8
-69.2
-53.8
-18.1
-18.5
-24,5
-30.8
-37.1
0.0
-69.2
18 
-43.4
*49.7
-56.1
-62.5
-68.4
-74.0
-77.7
-53.6
-52.7
-59.1
-65.5
-71.7
0.0
-77.7
19
-78.1
-84.5
-90.6
-96.1
-101.9
-108.2
-113.6
-78.6
-73.1
-79.1
-85.3
-91.7
0.0
-113.6
20
-97.9
-104.2
-110.6
-117.0
-123.3
-129.8
-112.3
-83.8
-78.5
-84.4
-90.0
-96.3
0.0
-129.8Table B.10
Example Jida Reservoir Regulation Computer Runs - 4
B-57
CUMULATIVE STORAGE (in
Drift Rati: 7.34 i*3/S
JAM         FEB        MAR        APR        MAY         JUN          JUL         AUG         SEP         OCT         NOV         DEC        SPILL    STORAGE
1           -7.1        -14.2        -21.3        -27.5        -34.1        -41.3        -22.0          67.3          13.1          -6.6
2         -27.3        -34.4        -41.5        -47.8        -54.2        -61.3        -47.6        -43.2        -46.0        -52.8
3         -74.1        -81.2        -88.4        -95.4     -102.4      -109.7           -5.5          29.0          12.3         -6.7
4         -28.0        -35.1        -42.2        -49.3        -56.4        -63.7        -69.3        -59.4        -60.8        -«8.1
5         -89.0        -96.2     -103.2      -110.2      -117.3      -124.4      -103.1          -55.8         -55.1        -62.1
6         -83.1        -90.2        -97.3     -104.4      -111.6      -118.6      -102.7          -47.2        -47.2        -54.0
7         -74.4        -81.4        -88.4        -95.5     -102.6      -109.8          -85.3          35.3          10.8          -6.0
9         -26.7        -33.7        -40.9        -48.1        -55.3        -54.5        -36.0          -8.2           -1.1          -7.2
9         -27.8        -35.0        -42.0        -49.0        -56.0        -45.2          25.9          29.3          12.3         -6.1
10         -27.5        -34.5        -40.9        -47.8        -54.7        -49.1          -5.1          37.7            4.9          -7.0
11         -28.5        -35.7        -42.8        -49.9        -57.1        -64.2        -49.6             7.0          -4.5        -11.4
12         -32.7        -40.0        -47.2        -54.5        -61.8        -68.9        -40.2          26.6            3.9          -6.6
13         -28.1        -35.1        -42.0        -49.1        -56.1        -63.2        -63.8        -18.8        -21.1         -28.0
14         -49.5        -56.7        -63.7        -70.8        -78.0        -84.9          -9.2          26.0           -0.1          -7.2
15         -28.5        -35.6        -42.7        -49.6        -55.8        -62.7        -46.7            1.1            0.9          -6.8
16         -27.5        -34.7        -41.1        -48.1        -55.1         -62.3        -60.5        -31.4        -22.2        -29.1 17         -50.5        -57.8        -64.9        -72.0        -79.1        -86.3        -71.7        -36.9         -38.1        -44.8 IB         -66.3        -73.4        -80.6        -87.8        -94.5     -100.9       -105.5          -82.1         -82.1        -89.3 19      -110.7      -117.9      -124.9      -131.1      -137.8      -144.9       -151.2         -116.9       -112.3    -119.0 20      -140.3      -147.5      -154.6      -161.8      -169.0      -176.3      -159.6         -131.9      -127.4    -134.2
-13.1         -20.2           80.5        -41.3
-59.8        -66.9             0.0        -66.9
-13.8        -20.9           41.3      -109.7
-74.8        -81.8             0.0        -81.8
-68.8        -75.9             0.0      -124.4
-60.4        -67.4             0.0      -118.6
-12.6         -19.6          46.1       -109.8
-13.5         -20.7             0.0        -55.3
-13.3        -20.4           67.4         -56.0
-14.2        -21.4           42.6        -54.7
-18.4         -25.5             7.0        -64.2
-13.8        -21.0           30.4         -68.9
-35.2         -42.3             0.0        -63.8
-14.3        -21.4           26.0        -84.9
-13.9         -20.5             2.0         -62.7
-36.2        -43.4             0.0         -62.3
-52.0        -59.2             0.0         -86.3
-96.4      -103.5             0.0       -105.5
-126.1 -133.3 0.0 -151.2
-140.6 -147.7 0.0 -176.3
CUMULATIVE STORAGE (in «*3/s)
Drift Rati: 8.16 ■''3/S
JAN         FEB         MAR        APR         HAY         JUN          JUL
1           -7.9        -15.8        -23.7        -30.8        -38.2        -46.2         -27.7
2         -30.6        -38.5        -46.4        -53.5        -60.7        -68.6         -55.8
3         -87.1        -95.1      -103.0      -110.9      -118.7      -126.8          -23.5
4         -31.3        -39.1        -47.1        -55.0        -62.9        -71.0          -77.4
5       -102.1      -110.1      -117.9      -125.7      -133.6      -141.6        -121.0
6       -105.9      -113.9      -121.7      -129.7      -137.6      -145.5       -130.4
7       -107.0      -114.8      -122.7      -130.6      -138.5      -146.5        -122.8
8         -29.9        -37.8        -45.8        -53.8        -61.8        -61.8         -44.2
9         -40.8        -48.8        -5n.7        -64.5        -72.4        -62.4             7.9
10 -30.7 -38.6 -45.8 -53.5 -61.2 -56.4 -13.2
11 -31.8 -39.8 -47.7 -55.6 -63.6 -71.5 -57.7
12 -38.7 -46.8 -54.9 -63.0 -71.1 -79.0 -51.1
13         -31.3        -39.2       -4e. 9        -54.8        -62.6        -70.5         -72.0
14         -62.5        -70.6        -78.4        -86.3        -94.3      -102.0          -27.2
15         -32.6        -40.5        -48.4        -56.1        -63.1         -70.8        -55.7
16         -39.4        -47.3        -54.6        -62.3        -70.2        -78.2          -77.2
17         -72.2        -80.2        -88.1        -96.1      -104.0      -112.0         -98.2
18         -97.7      -105.o      -113.6      -121.7      -129.2      -136.4        -141.8
19 -151.9 -159.9 -167.7 -174.8 -182.2 -190.1 -197.3
20      -191.3 -(99.3 -207.3 -215.3 -223.2 -231.4 -215.5
AU6 SEP OCT NOV DEC SPILL STORAGE
60.8          12.3         -7.4        -14.8         -22.6          73.1         -46.2
-52.2       -55.8         -63.4         -71.2         -79.2             0.0         -79.2
10.2          11.5          -7.5        -15.4        -23.4           21.8       -126.8
-68.3 -70.6 -78.7 -86.2 -94.1 0.0 -94.1 -74.5 -74.6 -82.5 -90.0 -97.9 0.0 -141.6
-75.8       -76.5         -84.2        -91.3         -99.2             0.0       -145.5
-3.0             7.0          -6.8        -14.2        -22.1             7.0       -146.5
-17.2        -10.9        -17.8         -25.0         -32.9             0.0         -61.8
28.4          11.5          -6.9        -14.9         -22.9           47.9         -72.4 28.7            4.1          -7.8        -15.8         -23.9           32.8         -61.2 -2.0           -7.3        -15.0         -22.9         -30.8             0.0         -71.5
14.8            3.1          -7.4         -15.5         -23.4           17.9         -79.0
-27.7         -30.9       -38.6         -46.6         -54.6             0.0         -72.0
7.3          -0.9          -8.8         -16.8         -24.7             7.3       -102.0
-8.7           -8.6        -16.2        -24.1         -31.5             0.0         -70.8
-46.9 -40.5 -‘8.3 -56.2 -e4.2 0.0 -78.2 -64.2 -6e.2 -73.8 -81.8 -89.8 0.0 -112.0
-119.2 -120.0 -128.1 -136.0 -143.9 0.0 -143.9 -163.8 -160.0 -167.6 -175.5 -183.5 0.0 -197.3 -188.6 -185.0 -192.5 -199.7 -207.7 0.0 -231.4Table B.10
Example Jida Reservoir Regulation Computer Runs - 5
B-58
Drift        Has Storage
Graft
Rite
Required
Spillige
Vol mi
Runoff
■ A3/S
N« A3
Ni A3
lta A3
lta A3
4.1          -146.9          2598.1         2570.5           5141.1
4.9          -191.9          2093.7         3084.7           5141.1
5.7          -236.9          16&3.1         3598.8           5141.1
6.5          -341.0          1281.2         4112.9           5141.1
7.3         -463.1            902.0         4627.0           5141.1
8.2          -607.8            545.4         5141.1           5141.1TABLE B.11
RESERVO1R-REGULATION
RELATIONSHIPS FOR
FINAL MODEL RUNS
Reservoir Volume
Required (Mm ) in
3
3
Long-Term Reservoir Volume Required (Mm )
Drainage Mean Annual for Degree of Regulation (%) Runs for Degree of
Preliminary Model
Site
Subbasin
Ar ea
Flow
50
60
70
80
90
100
Regulation - 100%
2
(km )
3
(m /s)
5b
Tiliku
4 58
5.57
66.3
106.8
149.2
202.9
297.7
401.1
317.1
Al elt u
6c
Ji da
749
8. 16
148.2
193.2
238.2
372.5
525.5
707.2
512.6
8a
Gomoro
225
2.41
27.5
35.9
49.3
73.4
129.8
198.0
169.1
9a
Robi
4 37
4.29
49.8
73.4
97.1
132.9
197.1
279.5
286.7
2a
Weserbi
168
2.30
28.5
42.2
72.6
107.7
143.1
182.0
130.8
12c
Duber
312
3.98
53.3
75.3
100.1
134.6
169.0
216.5
221.1
14a
Cbacha
590
6. 19
74.1
109.8
145.6
193.7
249.0
304.3
566.3
10a
Jinjer
2 38
2.24
40.3
52.6
65.9
97.0
133.0
189.8
160.4
4b
Ti nishu
37
0.47
5.6
6.8
9.1
11.7
15.3
20.4
-
Aleltu
7b
Robi -
272
2.79
32.1
44.6
60.1
85.7
139.2
204.9
-
GomoroB-60
regional frequency analysis was undertaken. For this pur
pose, extensive use was made of data collected for the 1982 Power Planning Study (PPS) and a total of 15 recording stations located on the Ethiopian plateau in the Blue Nile, Omo and Awash basins was considered.
Table B.12, Columns 1 to 6, contains a listing of these stations, their period of record, drainage area and the mean annual flood (MAF). Instantaneous peak flow data were not available for most of the recording stations and, Dased on assumptions made in tne PPS, a ratio of instantaneous peak flow to daily peak flow of 1.4 was adopted.
The MAF for each station was calculated as the arithmetic mean of the annual maximum instantaneous peax flows over the recording period.
B7.2 - Frequency Curves
As a first step in the regional analysis, flood frequency curves were calculated for all of the gauging stations using a 2-parameter lognormal probability function. This function was selected to provide the most consistently reliable solu tion for the short lengths of the available recordings. Because of the short lengths, the computed relationships do not permit reliable estimates to be made of extremely rare flood events, such as tne probable maximum flood (PMF). However, for the purpose of preliminary sizing cf structural components for the various subbasin developments, extrapola tions were carried out for a recurrence interval of
1:10 000 years. Additional studies will be required during future study phases to confirm the calculated flood flow values and to obtain reliable estimates of the PMF.TABLE B.12
RESULTS OF FLOOD
HYDROLOGY ANALYSIS
(1)
Bas 1 n
(2)
No,
(3)
River Gauging
Station
(4)
Per 1od
of
Record
(yr)
(5)
Drainage
Area*
(km2)
(6)
Mean
Annual
Flood*
(m3/s)
(7)
Statistical
Flood**
(ip/s)
(8)
Return
Period of
Statistical
Flood
(yr)
(9)
9 1.05
(m5/s)
(10)
Q 1.05/MAF
(-)
(11)
Q 20
(m^/s)
(12)
020^
(-)
B 1 ue
1
Chemoga near Debre
18
364
59
87
10.0
32
0.54
98
1.66
NlJe
Markos
2
Beressa near Debre
17
211
89
132
8.3
41
0.46
163
1.83
Berhan
3
Dabana near
18
3 281
278
411
22.2
182
0.65
403
1.45
Abas Ina
4
Amartl near Shambu
16
24 5
35
52
10.0
18
0.51
60
1.71
5
DIdessa near Arjo
10
9 981
810
1 199
21.3
521
0.64
1 192
1.47
6
Neshe near Shambu
17
322
30
44
11.1
17
0.57
48
1.61
7
Muger near Chancho
16
489
81
120
5.9
29
0.36
171
2.11
8
Chacha at Chacha
14
418
101
149
6.5
33
0.33
212
2.10
Omo 9 GlIgel Gibe near 14 2 966 177 262
Asendabo
20.4                    112          0.64                  261          1.48
10
GlIgel Glbe near
17
4 230
287
425
21.7
185
0.64
418
1.46
Deneba
11
Great Gibe at
15
15 746
1 009
1 493
33.3
691
0.68
1 412
1.40
Abaltl
12
Wabe near Wolkltle
12
1 866
345
511
6.7
143
0.41
692
2.01
13
Walga near
18
1 792
185
274
6.9
76
0.41
366
1.97
Wolkltle
14
Gogeb near Shebo
9
3 494
282
417
11.8
157
0.56
461
1.64
Awash
15
Awash near Melka
16
4 440
266
394
14.2
142
0.53
415
1.56
Konture
• For other slat Ion data, such as locations, recording length, etc, see the October 1982 PPS by Acres International Limited. (Column 6, maximum Installation.)
■■Mean annual flood of each station times average 10-yr ratio equals mean 1:IO-yr flood over 15 stations
MAF x ----------------
1
mean annual flood over 15 stations
----------------------------------------     1.48 x MAF3-62
B7.3 - Homogeneity Test
To assess if all of the gauging stations would represent a homogeneous hydrologic region, a Langbein homogeneity test was carried out. This test is based on comparing the slopes
of individual frequency curves to a mean curve calculated for the region. For this purpose, a statistical flood for each station was computed as follows.
Statistical               Flood =
 mean l:10-yr flood* 
MAF x               --                   — mean annual flood*
Table B.12, Columns 7 and 8, shows the statistical floods and their corresponding return periods. The results are plotted in the Langbein graph shown on Plate B-3, Figure 4. This graph contains 95% confidence limits and, as all points fall well within these limits, it was concluded that the 15 
stations can be considered to represent a homogeneous hydrologic region.
B7.4 - Flood Index Factors
Table B.12, Columns 9 to 12, summarizes flood peaks and ratios for the 1:1.05- and l:20-yr recurrence intervals. The
nondimensional values of Q
peaR M
/  AF for each station were
"Average over 15 stations.B-63
plotted to determine the flood index (FI) factors, which are
defined as the regional mean relationships between flood 
peaks and MAF. Table B.13 shows the derived FI factors.
B7.5 - Mean Annual Floods
The remaining  part of the flood  frequency  analysis consisted of determining  the relationship  between  the MAF and  drainage area.
For this purpose, the values in Columns 5 and 6, Table B.12, were plotted as shown on Plate B-3, Figure 5. A regression analysis, based on the least square method, was carried out to mathematically define the relationship. The following function was found.
MAF = 0.84       X A where
0.73
Gp = FI x (0.84 x A '
MAF = mean annual flood
A = the drainage area (km2)
B7.6 - Peak Flood Calculations
The 1:20- and 1:10 000-yr peak floods of the Aleltu schemes were calculated using the MAF function and FI factors as follows.
0 73)B-64
I.’.LEX FACTORS
Ev*-r.t
Index
Factor
*At' i-'.-j. f-'X.'i
1.00
* ; 5-7 r
1.25
1.45
>six-7'
»</'f»
1.60
1.83
2.00
2.56
3.10B-65
where
Qp = he peak flood with a recurrence interval correspond 
t
ing to that of the FI factor
FI = flood index factor
A = drainage area (km2)
Table B.14 shows the computed peak flows for the subbasins.
B7.7 - Inflow Hydrographs
In order to assess peak flood flow attenuation during reser voir surcharge conditions, the determination of flood inflow hydrographs to the reservoir was required. Use was made of daily peak recordings at the Chacha gauging station to derive nondimensional hydrograph shapes. These were plotted over a period of about 8 days for the four highest peak floods on record and an eye-fit average nondimensional shape was determined as shown on Plate B-3, Figure 6 (solid lines). It
is noted that the hydrograph base flow corresponds to about 10% of the peak flow. The nondimensional nydrograph shape was simplified by adopting a 6—d base period and a triangular configuration, as shown on Plate B-3, Figure 6 (dotted line). To reflect different response times of each subbasin consi dered, the base period of the hydrograph was multiplied by the ratio of the subbasin drainage area to that of the Chacha drainage area.B-64
TABLE B.13
FLOOD INDEX FACTORS
Flood Event
Mean annual flood
Index Factor 1.00
1:5-yr
1.25
1:10-yr
1.45
1:20-yr
1.60
1:50-yr
1.83
l:100-yr
2.00
1:1 000-yr
2.56
1:10 000-yr
3.10B-65
where
Qp = the peak flood with a recurrence interval correspond 
ing to that of the FI factor
FI = flood index factor
A = drainage area (km2j
Table B.14 shows the computed peak flows for the subbasins.
B7.7 - Inflow Hydrographs
In order to assess peak flood flow attenuation during reser voir surcharge conditions, the determination of flood inflow hydrographs to the reservoir was required. Use was made of daily peak recordings at the Chacha gauging station to derive nondimensional hydrograph shapes. These were plotted over a period of about 8 days for the four highest peak floods on record and an eye-fit average nondimensional shape was determined as shown on Plate B-3, Figure 6 (solid lines). It
is noted that the hydrograph base flow corresponds to aDout 10% of the peak flow. The nondimensional hydrograph shape was simplified by adopting a 6-d base period and a triangular configuration, as shown on Plate B-3, Figure 6 (dotted line). To reflect different response times of each subbasin consi dered, the base period of the hydrograph was multiplied by the ratio of the subbasin drainage area to that of the Chacha drainage area.B-66
TABLE B. 14
COMPUTED PEAK FLOWS
Site         Subbasin
Drainage
Area
2
(km )
J
Flood Flow (m /s)
MAF g20 Q50 g100 210 000
3a
Agat
92
22.8
36.5
41.7
45.6
70.6
4b
Tinishu
Aleltu
37
11.7
18.8
21 .5
23.4
36.3
5b
Tiliku
Aleltu
458
73.5
117.7
134.6
147.1
228.0
6c
Jida
749
105.4
168.6
192.8
210.7
326.6
8a
Gomcro
225
43.8
70.1
80.1
87.6
135.7
9a
Robi
437
71.1
113.7
130.1
142.2
220.4
2a
Weserbi
168
35.4
56.6
64.7
70.8
109.6
12c
Duber
312
55.6
88.9
101.7
111.2
172.3
14a
Chacha
590
88.5
141 .6
162.0
177.0
274.4
10a
Jinjer
238
45.6
73.0
83.5
91.2
141.4B-67
B8 - RESERVOIR SEDIMENTATION
No quantitative analyses were carried out to determine the potential for sedimentation of the subbasin reservoirs. However, based on the results of studies carried out at similar sites (Gilgel Gibe, Amarti, etc) and from inspections carried out during the field investigation programs of the Tiliku Aleltu and Jida prefeasibility study, it was qualita tively established that sediment transport in the rivers on the high plateau area is small, and would not alter the find ings of the reconnaissance and prefeasibility studies. Quan titative studies should be carried out in the feasibility study stage.
B9 - EVALUATION OF HYDROLOGIC ANALYSES
B9.1 - General
The hydrologic analyses described in this appendix are based on the availability and quality of hydrologic data. It is
shown that there are three discharge stations and some ten rainfall stations available along the perimeter of the Aleltu drainage basin, but there are no stations located at the main rivers of the oase schemes.
In July 1983, three discharge stations were estaolished at tne Tiliku Aleltu, Jida and Gomoro rivers along the Muke Turi-Lemi Road. These stations now have one wet season of flow data available. No comparative data at other stations could be made a/ailaole for this study and these data wouldB-68
as yet be insufficient to contribute significantly to the hydrologic analyses presented herein. Future analyses and, in particular, feasibility and design level studies must incorporate these flow data if confidence in the estimate of power generating flow is to be obtained.
Therefore, the need to operate these stations to maximize data accumulation, quality and continuity is essential for future studies.
The records of the available rainfall stations are mostly short and incomplete. This largely affects the correlation analyses carried out between these stations as there are few complete and overlapping years of record available. In future studies, an effort should be undertaxen to obtain 
up-to-date records and to fill in missing months and years. The lack of data within the basin and the brevity of most of the available records affect the accuracy of the estimated rainfall distribution (isonyets) over the drainage basin; and this affects, therefore, the accuracy of the flow
calculations for individual subbasins.
The discharge records of the three stations around the Aleltu project area are of reasonable length and are reasonably complete. It was shown that there is some confidence in the accuracy of the long-term mean annual flow which can be derived from these stations. However, no satisfactory annual, seasonal or monthly relationships between flow records or unavailable rainfall data could be established. Future studies should investigate this aspect in more detail and other discharge records should De considered as well.B-69
B9.2 - Inflow Sequences
The analysis carried out to determine synthetic inflow
sequences to typify the statistics of water supply by the
subbasins was particularly based on the estimation of long
term average rainfall and the use of historical, annual and 
monthly flow variability of the Chacha discharge record.
This statistical analysis therefore adopted  the characteris tics of the Chacha record  to  be representative of the entire Aleltu Basin. However, at the Muger station, some 100 km
west, the distribution of annual and monthly discharges is different from that at the eastern side of the basin, and it appears that the variation in the Chacha record is particu larly unfavorable compared to the Muger station. It is then tentatively considered that conservative estimates of the required reservoir storage volumes to regulate the natural inflows have been obtained in this study. This is evident in comparing the results of the initial and final model runs, from which it can be seen that the dam heights in the final model runs are about 7 m higher than in the initial runs. It
is therefore believed that dam height and storage volumes are conservatively estimated.
Because the long-term firm flow available from individual subbasins is determined from rainfall isohyets, the accuracy of these isohyets is of prime importance. No rainfall stations exist within the project basins and the availability of such stations would substantially improve the accuracy of the estimated isohyets.
Evaporation losses from the subbasin reservoirs were not considered in tne layout optimization model runs. Justifica tion for this approach was based on the limited accuracy of the reservoir volume requirements, both hydrologically and topographically, and that of the estimated inflow volumes.B-68
as yet be insufficient to contribute significantly to the hydrologic analyses presented herein. Future analyses and, in particular, feasibility and design level studies must incorporate these flow data if confidence in the estimate of power generating flow is to be obtained.
Therefore, the need to operate these stations to maximize data accumulation, quality and continuity is essential for future studies.
The records of the available rainfall stations are mostly short and incomplete. This largely affects the correlation analyses carried out between these stations as there are few complete and overlapping years of record available. In future studies, an effort should be undertaken to obtain 
up-to-date records and to fill in missing months and years. The lack of data within the basin and the brevity of most of the available records affect the accuracy of the estimated rainfall distribution (isohyets) over the drainage basin; and this affects, therefore, the accuracy of the flow
calculations for individual subbasins.
The discharge records of the three stations around the Aleltu project area are of reasonable length and are reasonably complete. It was shown that there is some confidence in the accuracy of tne long-term mean annual flow which can be derived from these stations. However, no satisfactory annual, seasonal or monthly relationships between flow records or unavailable rainfall data could be established. Future studies should investigate this aspect in more detail and other discharge records should be considered as well.B-69
B9.2 - Inflow Sequences
The analysis carried out to determine synthetic inflow sequences to typify the statistics of water supply by the subbasins was particularly based on the estimation of long term average rainfall and the use of historical, annual and monthly flow variability of the Chacha discharge record.
This            statistical
analysis
therefore            adopted            the            characteris
tics       of       the       Chacha       record       to       be       representative       of       the       entire Aleltu Basin. However, at the Muger station, some 100 km
west, the distribution of annual and monthly discharges is different from that at the eastern side of the basin, and it appears that the variation in the Chacha record is particu larly unfavorable compared to the Muger station. It is then tentatively considered that conservative estimates of the required reservoir storage volumes to regulate the natural inflows have been obtained in this study. This is evident in comparing the results of the initial and final model runs, from which it can be seen that the dam heights in the final model runs are about 7 m higher than in the initial runs. It
is therefore believed that dam height and storage volumes are conservatively estimated.
Because the long-term firm flow available from individual subbasins is determined from rainfall isohyets, the accuracy of these isohyets is of prime importance. No rainfall
stations exist within the project basins and the availability of such stations would substantially improve the accuracy of the estimated isohyets.
Evaporation losses from tne subbasin reservoirs were not considered in tne layout optimization model runs. Justifica tion for this approach was based on the 1imited accuracy of the reservoir volume requirements, botn hydrologica1ly and topographically, and that of the estimated inflow volumes.B-70
Evaporation losses, however, were included for the prefeasibility estimates of the energy yield from the Tiliku Aleltu and Jida schemes. It is obvious tnat evaporation 
effects should be introduced in future layout model runs when more accurate data become available and improved analyses will be carried out.
It is noted that evapotranspiration measurements in the
Aleltu project area would greatly contribute to future evaporation analyses.
B9.3 - Flood Flows
The probability analysis carried out to determine flood flows
in the Aleltu Basin was based on a regional analysis of flow data. Daily peak discharges of stations as far away as the
Omo Basin were considered in this analysis and average rela tionships between frequency factors and the MAF were adopted. Based on the peak flows of the Chacha and Muger basins, it appears that local rainfall concentrations significantly 
affect the flood flow characteristics in that region and further analyses are required to determine more accurately such effects on the Aleltu Basin peak flows. Furthermore, it is noted that the Chacna and Muger record lengths are insuf ficient to calculate a reliable estimate of the PMF or
1:10 000-yr flood inflows. Future studies, therefore, need to be directed to establishing relationships with much longer records available outside the region considered in this analysis.W30
LEGEND
RAINFALL STATION
STREAM FLOW STATION
RAINFALx. ISOHYETS DETERMINED FROM
-  RAINFALL STATION RECORDS
-  HYDROLOGIC ATLAS OF ETHIOPIA (19^1 PERIMETER OF PROJECT DRAINAGE AREA
OMITS OF SUBBASINS
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY AlELTu HYDROELECTRIC
PLATE B-1
HYDROLOGIC DATAk«
roo
* *
* *
kilometres
LEGEND
RAINFALL STATION
STREAM FLOW STATION
RAINFALl. isohyets determined from
-  RAINFALl. station records
-  HYDROLOGIC atlas OF ETHIOPIA (1979) -------------- PERIMETER OF PROJECT DRAINAGE AREA
-------------- LIMITS OF SUBBASINS
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY
ALELTO HYDROELECTRIC PROJECT
0
HYDROLOGIC DATA BASE    ULBYEARS OF RECORD
>7
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
aaaiaai
iiaaaaai
aaaaaaai
aeaaaai
aiaaan
■■■■■II
8888881
laaaBBBI kaiaiiu
iiiaaii
■aaaiaa
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY [—’— ALELTlI HYDROELECTRIC PROJECT innrn
HYDROMETRIC RECORDING STATIONS Mill)ROI_OGY
N EXCEEDANCE CURVES
DLOGY
FIG. 3-RAINFALL/RUNOFF RELATIONSHIP OF CHACHA AND MUGER STATIONS
2
lA \ km )
iN ANNUAL FLOOD
FIG   6-TYPICAL   NON-DIMENSIONAL   FLOOD HYDROGRAPH AT CHACHA
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY
ALELTU HYDROELECTRIC project
PLATE B
HYDROLOGY STUDIES-DETAILS  HAPPENDIX C
TABLE OF CONTENTS
LIST    OF    TABLES LIST OF PLATES
Page
Cl -        GENERAL--------------------------------------------------------------------------------------------- C-
1
C2 -       DATA COLLECTION AND REVIEW------------------------------------------------------------ C-
2
C2.1 - Field Investigation Program--------------------------------------------------------------- C-
2
C2.2 - Review of Existing Data-------------------------------------------------------------------  C-
3
C3 -      GEOLOGY--------------------------------------------------------------------------------------------- C-
4
C3.1 - Regional Geology---------------------------------------------------------------------------  C-
4
C3.2 - Damsite Geology---------------------------------------------------------------------------- C-
6
C3.3 - Gorge Geology------------------------------------------------------------------------------- C-
6
C3.3.1 - General-------------------------------------------------------------------------------------- C-
6
C3.3.2 - Major Rock Units-------------------------------------------------------------------------- C-
7
C4 -      REGIONAL SEISMOLOGY----------------------------------------------------------------------------
C-15
C4.1      - General---------------------------------------------------------------------------------------
C-15
C4.2      - Earthquake          Data--------------------------------------------------------------------
C-16
C4.3      - Evaluation           Methods--------------------------------------------------------------  C-17
C4.4      - Seismicity            of Aleltu Basin------------------------------------------------------- C-19
C5 - SOILS AND MATERIALS INVESTIGATIONS --------------------------------------------  C-21
C5.1 - Test Pits and Auger Holes------------------------------------------------------------- C-21
C5.2 - Laboratory Testing----------------------------------------------------------------------- C-22
C5.3 - Test Pit Reports--------------------------------------------------------------------------- C-23
TEST PIT REPORTS PLATESAPPENDIX C
TABLE OF CONTENTS
LIST    OF    TABLES LIST OF PLATES
Cl - GENERAL
C- 1
C2 - DATA COLLECTION AND REVIEW----------------------------------------------------------------- C- 2
C2.1 - Field Investigation Program -------------------------------------------------------------- C- 2
C2.2 - Review of Existing Data------------------------------------------------------------------- C- 3
C3 -       GEOLOGY--------------------------------------------------------------------------------------------- C-       4
C3.1 - Regional Geology--------------------------------------------------------------------------- C-       4
C3.2 - Damsite Geology---------------------------------------------------------------------------- C-       6
C3.3 - Gorge Geology------------------------------------------------------------------------------- C-       6
C3.3.1 - General-------------------------------------------------------------------------------------- C-       6
C3.3.2 - Major Rock Units-------------------------------------------------------------------------- C- 7
C4 -      REGIONAL SEISMOLOGY---------------------------------------------------------------------------- C-15
C4.1 -         General-------------------------------------------------------------------------------------- C-15
C4.2 -         Earthquake       Data--------------------------------------------------------------------- C-16
C4.3 -         Evaluation         Methods--------------------------------------------------------------- C-17
C4.4 -         Seismicity         of Aleltu Basin-------------------------------------------------------- C-19
C5 - SOILS AND MATERIALS INVESTIGATIONS ------------------------------------------------- C-21
C5.1 - Test Pits and Auger Holes-------------------------------------------------------------- C-21
C5.2 - Laboratory Testing ----------------------------------------------------------------------- C-22
C5.3 - Test Pit Reports--------------------------------------------------------------------------- C-23
TEST PIT REPORTS PLATESAPPENDIX C
LIST OF TABLES
Number            Title
C. 1 Earthquake IntensitiesAPPENDIX C
LIST OF PLATES Number            Title
C-l
Geology of Tiliku Aleltu Dam Site
C-2
Geology of Jida Dam Site
C-3
Geological Section of Zega Wedem Gorge
C-4
Geological Stereonets
C-5
Seismicity of Ethiopia
C-6
Potential Jima Impervious Borrow Area
C-7
Properties of Impervious MaterialsAPPENDIX C
LIST OF TABLES
Number          Title
C.l Earthquake IntensitiesAPPENDIX C
LIST OF PLATES Number            Title
C-l
Geology of Tiliku Aleltu Dam Site
C-2                   Geology of Jida Dam Site
C-3                   Geological Section of Zega Wedem Gorge C-4                   Geological Stereonets
C-5                   Seismicity of Ethiopia
C-6                   Potential Jima Impervious Borrow Area C-7                   Properties of Impervious MaterialsAPPENDIX C
GEOLOGY, GEOTECHNICAL INVESTIGATIONS AND SEISMICITY
Cl - GENERAL
The geological and geotechnical investigation programs were carried out with the following objectives.
(a)       To determine the geological setting of the project.
(b)       To assess the foundation conditions at the two damsites selected for the first stage development in order to prepare adequate and economic design of the dams and associated conveyance structures.
(c)       To locate natural construction materials.
(d)       To identify the major rock units in the gorge and to evaluate the characteristics of each unit in order to select a technically feasible route for the penstock and power tunnel.
(e)       To locate the powerhouse on a competent bedrock foun dation in the gorge as far downstream as possible to maximize the available head and the resulting energy.
(f)        To evaluate the seismicity of tne Aleltu Basin and determine the seismic design criteria for the project structures.C-2
(g)       To produce preliminary designs of dams, rock-cut slopes, and rock support system for the tunnels and portals to a level sufficient to determine the economical and techni cal viaDility of the project at the prefeasibility 
level.
C2 - DATA COLLECTION AND REVIEW
C2.1 - Field Investigation
Program
Geological field investigations were carried out by an
integrated team of the Ethiopian Electric Light and Power
Authority and Acres International Limited (EELPA/Acres) geo
logists and geotechnical engineers during October and
November 1983. The field program was periodically reviewed
with senior staff of EELPA Planning and Programming
Department before execution.
A      helicopter      was      used      for      the      flyover      reconnaissance      of      the gorge      and      the      damsites      in      the      plateau.      Fly      tent      camps      were set     up     and     moved     to     various     places     in     the     gorge     and     plateau as the geological mapping progressed.
General geological maps and seismic data were reviewed to establish the regional geology and seismology with respect to tne project area.
Geological mapping and test pitting were carried out at tne proposed dam locations and potential borrow areas. A general geological survey of the gorge was made along the selectedC-3
penstock route. In the powerhouse area, a detailed survey 
was undertaken, including a geological mapping.
Selected soil samples were transported to laboratories in
Addis Ababa. Routine testing of soil samples was carried out
mainly in the EELPA materials testing laboratory. Laboratory 
facilities at Addis Ababa University was also used for
carrying out some specialized soil tests.
C2.2 - Review of Existing Data
Available seismological and geological maps, aerial
photographs and geological reports were reviewed. The geo
logical maps included those published by the Department of
the Interior United States Bureau of Reclamation (USBR) 1964
study of the Blue Nile River Basin,* and a more recent
Geological Map of Ethiopia published by the Ethiopian
Ministry of Mines and Energy.
Aerial       photography       at       1:10       000       scale       was       available       for       study of the area of the power facilities and damsites.
Seismological information consisted of the comprehensive work of Pierre Gouin which is described in detail in Section C4. During the field investigation program, the Ethiopian geo physical observatory was also visited to aiscuss the
seismicity of the Aleltu Basin.
«USBR, Land and Water Resources of the Blue Nile Basin, Etmopla (Seven Volumes), prepared for the Department of State Agency for International Development, 1964.C-2
(g) To produce preliminary designs of dams, rock-cut slopes, and rock support system for the tunnels and portals to a level sufficient to determine the economical and techni cal viability of the project at the prefeasibility 
level.
C2 - DATA COLLECTION AND REVIEW
C2.1 - Field Investigation
Program
Geological field investigations were carried out by an
integrated team of the Ethiopian Electric Light and Power
Authority and Acres International Limited (EELPA/Acres) geo
logists and geotechnical engineers during October and
November 1983. The field program was periodically reviewed
with senior staff of EELPA Planning and Programming
Department before execution.
A      helicopter      was      used      for      the      flyover      reconnaissance      of      the gorge      and      the      damsites      in      the      plateau.      Fly      tent      camps      were set     up     and     moved     to     various     places     in     the     gorge     and     plateau as the geological mapping progressed.
General geological maps and seismic data were reviewed to establish the regional geology and seismology with respect to the project area.
Geological mapping and test pitting were carried out at the proposed dam locations and potential borrow areas. a general geological survey of the gorge was made along tne selectedC-3
penstock route. In the powerhouse area, a detailed survey 
was undertaken, including a geological mapping.
Selected soil samples were transported to laboratories in
Addis Ababa. Routine testing of soil samples was carried out
mainly in the EELPA materials testing laboratory. Laboratory 
facilities at Addis Ababa University was also used for
carrying out some specialized soil tests.
C2.2 - Review of Existing Data
Available seismological and geological maps, aerial
photographs and geological reports were reviewed. The geo
logical maps included those published by the Department of
the Interior United States Bureau of Reclamation (USBR) 1964
study of the Blue Nile River Basin,* and a more recent
Geological Map of Ethiopia published by the Ethiopian
Ministry of Mines and Energy.
Aerial       photography       at       1:10       000       scale       was       available       for       study of the area of the power facilities and damsites.
Seismological information consisted of the comprehensive work of Pierre Gouin which is described in detail in Section C4. During the field investigation program, the Ethiopian geo physical observatory was also visited to aiscuss the
seismicity of the Aleltu Basin.
*USBR, Land ana Water Resources of the Blue Nile Basin, Ethiopia (Seven Volumes), prepared for the Deparr.mpnr of State Agency for International Development, 1964.C-4
Following the review of all documents, a geological mapping and a test pit exploration program were carried out.
C3 - GEOLOGY
C3.1 - Regional Geology
Ethiopia lies along the main oceanic boundary between two major tectonic plates, namely, the African and Arabian
plates; and also straddles the East African Rift System.
The oldest rocks in Ethiopia, with ages over 600 million
years, are the sheared and folded Precambrian metamorphic and granitic rocks, referred to as the crystalline basement
complex. Most of the Precambrian rocks are relatively imper meable, and have been subjected to several orogenic episodes since their formation. This process, combined witn the rift
ing associated with the development of the Ethiopian Rift Valley, has resulted in considerable fracturing and
shattering.
At the end of the Precambrian times, uplift occurred which was followed by a long period of erosion. Any sediments wnich were deposited during the Paleozoic interval, which lasted some 375 million years, have been largely removed by erosion. Such a long period of erosion and denudation left
the earth's surface of East Africa and Etniopia completely peneplained.
Crustal motion started in the beginning of Mesozoic period about 225 million years ago. During the late Triassic and early Jurassic periods, a regional epeirogenic sinking of theC-5
crust commenced causing a progressive transgression of the
ocean from the southeast, that is, from the Indian Ocean
coast of present Somalia in the general direction of Lake
Tana in northwest Ethiopia. This downward crustal movement,
concomitant with a sedimentation process, started a cycle of
marine transgression and recession of the Mesozoic sea.
Within this large epicontinental sea, extensive layers of
sediments were deposited to form hundreds of metres of rocks 
consisting of sandstone, shale, gypsum, limestone and otner
varieties of bedded rocks. The crustal movement was reversed
into a upward motion during the late Jurassic period which
brought the crust’s surface up to sea level by the end of the
Mesozoic period, 65 million years ago, and finally uplifted
it through intermittent but progressive phases throughout
Tertiary and Quaternary times to the present level of more
than 3,000 m above sea level.
Extensive        fracturing        occurred        within        the        earth's        crust        by        the doming process due to progressive uplift early in the
Cenozoic period (the earliest rocks of which are dated
65 million years), although major displacement along the fault systems did not occur until later in the Tertiary 
period. Faulting was accompanied by widespread volcanic activity and the two processes, which are partly related, have largely determined the form of the landscape in the western naif of Ethiopia and in the Afar depression. The outpouring of vast quantities of basaltic lava over the western half of the country was accompanied by, and alter nated with the eruption of large amounts of ash and coarser fragmental material, forming the Trap Series. More recent volcanism is associated with the development of the Rift System, activity being concentrated within tms structure and along tne edge of the adjoining plateau.C-6
C3.2 - Damsite Geology
Geological mapping was carried out for the prefeasibility damsites. These mappings are based on aerial photography, existing mapping and ground level and aerial reconnaissances. The geological mapping of the damsites is shown on Plates C-l and C-2.
C3.3 - Gorge Geology
C3.3.1 - General
Site investigations along the power tunnel and pen stock alignment consisted of geologic mapping of bedrock outcrops as close to the alignment as possi- ble.        The results of the geological mapping are summarized as a geological section of the gorge and shown on Plate C-3.
The outcrops found mainly along the Agat at lower elevations and along the gullies and cliff faces at upper elevations were considered typical for the gorge face. All mapped outcrops on the gorge face were connected by a survey traverse. The field notes collected on outcrop samples include rock type, color, grain size, strength, degree of weathering, jointing and rock mass fabric. Stereonets showing the distri bution of jointing were plotted and contoured as shown on Plate C-4.
The elevations and thickness of various units shown are approximate only and applicable only close to the alignment. Lower rock units in the gorge were basedC-7
on mapping the outcrops along the Agat River and projected to the proposed alignment. Some generaliza tions and approximations were found necessary because of almost near vertical inaccessible outcrops of
stronger units and lack of outcrops of extensively weathered weaker units.
C3.3.2 - Major Rock Units
Surface geological mapping indicates 14 major rock units along the proposed power tunnel and penstock alignment, and a brief description of each unit
starting from the bottom of the gorge is given below.
Shale with Lenses 
of Sandstone___________
(From el 1,511 to 1,527)
The shale is generally of variegated type with
colors grading from grayish to pinkish, fine to very fine grained, very weak to weak at the surface, very thin to thinly bedded, moderately weathered to
highly weathered with lenses of moderately weak to moderately strong sandstone. Beddings are extremely continuous to greater than 2 m with evidence of pronounced cross—bedding in places. Seepage was observed along the contact Detween sandstone and shale at river level.
Sandstone with Interbeds 
of Snale and Mudstone
(From el 1,527 to 1,553)
The sandstone is interbedded witn thin to medium beds of shale and mudstone, generally gray in color,C-6
C 3.2 - Damsite Geology
Geological mapping was carried out for the prefeasibility damsites. These mappings are based on aerial photography, existing mapping and ground level and aerial reconnaissances. The geological mapping of the damsites is shown on Plates C-l and C-2.
C3.3 - Gorge Geology
C3.3.1 - General
Site investigations along the power tunnel and pen stock alignment consisted of geologic mapping of bedrock outcrops as close to the alignment as possi- ble.        The results of the geological mapping are summarized as a geological section of the gorge and shown on Plate C-3.
The outcrops found mainly along the Agat at lower elevations and along the gullies and cliff faces at upper elevations were considered typical for the gorge face. All mapped outcrops on the gorge face were connected by a survey traverse. The field notes collected on outcrop samples include rock type, color, grain size, strengtn, degree of weathering, jointing and rock mass fabric. Stereonets showing the distri bution of jointing were plotted and contoured as shown on Plate C-4.
The elevations and thickness of various units shown are approximate only and applicable only close to the alignment. Lower rock units in the gorge were basedC-7
on mapping the outcrops along the Agat River and projected to the proposed alignment. Some generaliza tions and approximations were found necessary because of almost near vertical inaccessible outcrops of
stronger units and lack of outcrops of extensively weathered weaker units.
C3.3.2 - Major Rock Units
Surface geological mapping indicates 14 major rock units along the proposed power tunnel and penstock alignment, and a brief description of each unit
starting from the bottom of the gorge is given below.
Shale with Lenses 
of Sandstone__________
(From el 1,511 to 1,527)
The shale is generally of variegated type with
colors grading from grayish to pinkish, fine to very fine grained, very weak to weak at the surface, very thin to thinly bedded, moderately weathered to
highly weathered with lenses of moderately weak to moderately strong sandstone. Beddings are extremely continuous to greater than 2 m with evidence of pronounced cross—bedding in places. Seepage was observed along tne contact between sandstone and shale at river level.
Sandstone with Interbeds 
of Shale and Mudstone
(From el 1,527 to 1,553)
The sandstone is interbedded with thin to medium beds of shale and mudstone, generally gray in color,C-8
fine to very fine grained, moderately weak to moderately strong, slight to moderately weathered. Beddings in general are extremely continuous with evidence of cross-bedding in places. Thin localized places of lignite were also present and these beds are not as continuous as the sandstone beds. Joint ing is well developed and generally conforms to the regional trend shown on Plate C-3. Spacing of joints varies from 0.5 to greater than 1.0 m.
Shaly Limestone
with Interbeds of
Mudstone and Shale
(From el 1,553 to 1,613)
The sandy limestone is interbedded with medium to thick interbeds of calcareous mudstone, gypsum and carbonaceous shale, light gray to whitish in color, fossiliferous toward top, strong to very strong, faulted with fault displacements varying from 2 to 40 cm. The sandy limestone is fresh to faintly weathered whereas the mudstone shale is moderately weathered. The strength of shale and mudstone interbeds is moderately weak. The gypsum encoun tered at lower elevations was more of massive and amorphous type. Thin sheets of well developed and crystallized gypsum were observed at higher eleva tions. Large solution cavities were observed along the contact of gypsum and limestone, and the natural stream in many places passes through these
cavities.
Sandstone
(From el 1,613 to 1,989)
The sandstone unit is the thickest of all units mapped in the gorge and is about 376 m thick along C-9
the proposed power tunnel and penstock alignment. Most of the slope failures and slope instabilities
in the gorge were related to this sandstone unit. The sandstone is light gray to white at bottom and grading to pinkish toward top due to oxidation, fine to medium grained with occasional gritty coarse layers of mostly quartz, moderately weak to weak, very thickly bedded with evidence of cross-bedding, poorly cemented, slight to moderately weathered. The joints are widely spaced and extremely continuous to greater than 2 m.
Lower Basalt
(From el 1,989 to 2,093)
The lower basalt consists of two flow units and the contact between lower flow unit and sandstone appears to be tight and no apparent weakness is observed. Both flow units of basalt are dark bluish-gray in color, fine grained, and strong to very strong, blocky toward top, vesicular and scoriaceous in places. Jointing is mostly columnar and close- to medium-spaced. Subhorizontal joints with waviness were observed at the upper portion of lower flow unit. The amplitude of tne waviness is up to 2 m in places and the waviness is probably due to variation in strength of poorly cemented underlying sandstone.
The contact between flow units about 2 m thick, moderately weak to weak, very close to closely jointed, vesicular toward top witn inclusions of calcite and thin beds of vitrified wood.C-10
Lower Lacustrine
(From el 2,093 to 2,137)
This unit is very thin compared to other rock units in the gorge and mostly covered by talus and culti vated field. No significant exposures were encoun tered around the penstock route. Scattered odd outcrops of silicified mudstone were observed at contact with lower basalt. Exposures elsewhere on the other side of Agat at the same level indicate strong welded tuff mixed with vesicular basalt.
Agglomerate
(From el 2,137 to 2,275)
The agglomerate consists of three massive units and is of cliff-forming character. It is light gray to light brown in color, composed of an average 40% cobbles with sizes ranging from 1 to 70 cm, strong to very strong, faintly weathered, very widely jointed and thickly bedded. The contact Detween flow units is about 1-m thick and consists of
moderately weak to weax tuffaceous ash.
Middle Basalt
( From el 2,27 5 to 2,307)
The middle basalt is dark gray in color, fine grained, strong to very strong, columnar jointed with an average block size of 20 cm, faintly weathered. This unit does not appear to oe continuous laterally.C-l 1
Upper Lacustrine
(From el 2,307 to 2,389)
The upper lacustrine unit is probably deposited in a shallow deltaic environment and a typical outcrop, from top to bottom, consists of
-    light gray ash tuff, massive, moderately strong, poorly cemented and friable, slightly weathered
-   light gray sandy siltstone, fine to medium
grained, tnin to medium bedded with laminations of shale, moderately weak, moderately weathered
-    light gray mudstone, very weak and crumbling, moderately weathered
-   brownish shale, very thinly laminated, weak, moderately weathered
-    light gray sandy siltstone, fine to medium
grained, moderately weak, moderately weathered
-    light gray to pinkish silicified mudstone, moderately strong, slightly weathered
-   middle basalt.
Exposures elsewhere near Debre Libanos church on the otner side of Agat at the same level indicate the presence of carbonaceous shale and lignite.C-12
Upper Basalt - First
and Second Flow Units
(From el 2,389 to 2,485)
The first unit is about 62 m thick and the second 
unit is about 34 m thick. Both units of basalt are
dark gray, fine grained, slightly vesicular, strong 
to very strong, fresh to faintly weathered, columnar
jointed with block sizes ranging from 30 to 50 cm. 
The vesicles in the first flow unit are generally 
filled with secondary mineralization.
The contact between the lower lacustrine and first
flow unit is about 2 m thick and, from top to 
bottom, consists of
-      brown      grading      to      dark      gray      ash      tuff,      moderately strong,       highly       weathered       and       altered       by       contact metamorphism
- dark gray siltstone with dark strains, moderately weak, highly weathered
- yellowish ash tuff, moderately strong, moderately weathered.
The contact between the two flow units of basalt is about 4.5 m tnick and consists of highly weathered and generally weak to very weak basalt with closely spaced columnar joints. The upper 2.5 m of contact is light to reddish brown in color and probably nardened by contact metamorphism.C-13
Basic Breccia
and Pyroclastics
(From el 2,485 to 2,515)
The basic breccia and pyroclastics are considered as
part of the upper basalt and referred to as third 
flow unit. A typical outcrop of this unit indicates
pyroclastic overlying basic breccia. The basic
breccia consists of the mixture of rough "aa" sur
face and other basaltic angular to subangular frag
ments from 1 mm to 6 cm, weak to moderately weak, 
moderately weathered with inclusions of fossilwood.
The       fragments       are       massive       and       vesicular       and       probably constitute about 20% Dy volume.
The pyroclastic is light gray to yellowish lapillus ash tuff grading to ash tuff with depth, very light
in weight, fine to medium grained with inclusions of volcanic glass in places, generally weak with moderately strong intercalations, thin to medium bedded and medium jointed, beds tilted locally and extremely continuous to greater than 2 m. The upper portion of this unit is locally interbedded with 
thin to medium beds of lignite.
The contact at the bottom between the breccia and the underlying basalt is very rough because of "aa" surface and generally is tight without any paleosol. The contact zone consists of highly weathered zone of about 3 m thick and part of it is hardened by contact metamorpnism.
The contact between the pyroclastic and the over- lying basalt is about 5 m thick. The bottom 4 m is moderately weathered to highly weathered, and partC-12
Upper Basalt - First
and Second Flow Units
(From el 2,389 to 2,485)
The first unit is about 62 m thick and the second unit is about 34 m thick. Both units of basalt are dark gray, fine grained, slightly vesicular, strong to very strong, fresh to faintly weathered, columnar jointed with block sizes ranging from 30 to 50 cm. The vesicles in the first flow unit are generally filled with secondary mineralization.
The contact between the lower lacustrine and first flow unit is about 2 m thick and, from top to bottom, consists of
- brown grading to dark gray ash tuff,
strong,        highly weathered and altered metamorph ism
- dark gray siltstone with dark strains, moderately weaK, highly weathered
- yellowish ash tuff, moderately strong, moderately weathered.
The contact between the two flow units of basalt is about 4.5 m thick and consists of highly weathered and generally weak to very weak basalt with closely spaced columnar joints. The upper 2.5 m of contact is light to reddish brown in color and probably nardened by contact metamorphism.
moderately
by contactC-13
Basic Breccia
and Pyroclastics
(From el 2,485 to 2,515)
The basic breccia and pyroclastics are considered as
part of the upper basalt and referred to as third 
flow unit. A typical outcrop of this unit indicates
pyroclastic overlying basic breccia. The basic
breccia consists of the mixture of rough "aa" sur
face and other basaltic angular to subangular frag
ments from 1 mm to 6 cm, weak to moderately weak, 
moderately weathered with inclusions of fossilwood.
The       fragments       are       massive       and       vesicular       and       probably constitute about 20% by volume.
The pyroclastic is light gray to yellowish lapillus ash tuff grading to ash tuff with depth, very light
in weight, fine to medium grained with inclusions of volcanic glass in places, generally weak with moderately strong intercalations, thin to medium bedded and medium jointed, beds tilted locally and extremely continuous to greater than 2 m. The upper portion of this unit is locally interbedded with 
thin to medium beds of lignite.
The contact at the bottom between the breccia and tne underlying basalt is very rough because of "aa" surface and generally is tight without any paleosol. The contact zone consists of highly weathered zone of about 3 m thick and part of it is nardened by contact metamorphism.
Tne contact between the pyroclastic and the over- lying basalt is aDout 5 m thick. The bottom 4 m is moderately weathered to highly weathered, and partC-14
of it is hardened by contact metamorphism. The top 
1 m is part of the overlying basalt and is highly weathered to weak. Evidence of leaching and solu tion deposits on the surface were observed in both rock types on the exposed face.
Upper Basalt -
Fourth Flow Unit
(From el 2,515 to 2,541)
The fourth flow unit of basalt is dark gray in 
color, fine grained, slightly vesicular at the
bottom becoming highly vesicular toward the top with openings up to 3 cm wide, very strong, fresh to faintly weathered, columnar jointed with block sizes ranging from 10 to 100 cm. This unit in highly weathered form is exposed on the low-lying areas of the plateau and the color of these exposures is generally white possibly due to the leaching of
mafic minerals.
The contact between the fourth flow unit of basalt and the overlying pyroclastic appears to be grada tional with a thick highly weathered zone and was not easily recognizable in the field.
Pyroclastic
(From el 2,541 to 2,561)
The pyroclastic between the fourth and fifth flow units of basalt is an interoedded lapillus tuff, lapillus ash tuff and ash tuff, moderately weak to 
moderately strong, slightly weathered, medium bedded. This unit in low-lying areas around Agat is eroded and observable along the edges of trie plateau and near prominent hills such as the Mite Hill.C-15
Upper Basalt -
Fifth Flow Unit
(From el 2,561 to 2,600)
The top of the fifth flow unit of basalt forms the surface of the plateau and is dark gray in color, fine grained, very strong, fresh to faintly 
weathered, columnar jointed with an average block size of about 15 cm.
C4 - REGIONAL SEISMOLOGY
C4.1 - General
Ethiopia has experienced the effects of earthquakes and volcanic activity throughout its history due to its geo graphic location in the vicinity of two seismically active tectonic features. These are the major tectonic plate boun dary which divides the continental Africa from the Arabian peninsula and tne major break in the earth's crust due to the East African rift systems. Seismic activity in Ethiopia, as it relates to the Aleltu project, is shown on Plate C-5, Figures 1 and 2.
The methodology used and the results pertaining to the evaluation of seismicity of tne Aleltu Basin are described in the following sections.C-16
Pierre Gouin made a comprehensive study of the seismicity of Ethiopia* by compiling, in a logical manner, the earthquake records dating back to 1400 A.D. This study was, therefore, essentially an analysis of historical data.
C4.2 - Earthquake Data
The data file for the 575 years of earthquake history, on the whole, is neither sufficiently accurate nor numerically complete enough to be subjected to statistical analysis. It
was, therefore, necessary to select within that historical
period a time interval which could be considered as the best representative sample of the current seismic activity. The
more modern events confirmed by instrumental recordings from either local or foreign seismic stations during the period 
from 1875 to 1974 were- considered scientifically reliable and were used as the basis for the evaluation of seismicity of Ethiopia. Plate C-5, Figure 3, snows the location of all
seismic events that can be assigned reliable geographic coor dinates with enough accuracy. The estimated magnitudes of all the seismic events are shown on Plate C-5, Figure 4. The extent of the Aleltu Basin is also shown on these location maps. The Aleltu Basin is along the margin of the Rift System where largest number of epicenters and volcanoes are located.
•Gouin, P., "Eartnquake History Africa," Publication No. 118e, Research Centre, Canada, 1977.
of     Ethiopia     and     the     Horn     of International DevelopmentC-17
C4.3 - Evaluation Methods
(a)      Summary
The seismicity distribution over the country was obtained by summing up and contouring the amplitudes experienced at a series of selected reference points distributed over Ethiopia. A total of 650 reference points formed the grid. For each point on the grid, the amplitudes experienced from each seismic event regis tered for the period from 1875 to 1974 were computed in terms of intensities and ground accelerations. Inten sities are given in modified Mercalli (MM) units and the ground accelerations in percentage of the standard gra vitational acceleration, g. The predicted acceleration 
and intensity values were plotted on the base map and then contoured as shown on Plate C-5, Figures 6 and 7.
(b)      Attenuation
Computation of intensity from independent seismic events requires attenuation characteristics of the site, i.e., 
how the intensity of the resulting ground motion decreases with distance from the origin of an earth
quake. No quantitative measurements of ground motion in Ethiopia are available to derive an attenuation rela tionship from actual measurements in the region. There fore, the rates of attenuation were obtained by deriving quasi-equivalent geological and crustal conditions. The dominant crustal structures in Ethiopia are the rift and 
the plateau. A suitable analogy of these two crustal structures occurs on the North American Continent— California on West Coast can be approximated to the tectonically disturbed rift regions of Ethiopia; andC-16
Pierre Gouin made a comprehensive study of tne seismicity of Ethiopia’ by compiling, in a logical manner, the earthquake records dating back to 1400 A.D. This study was, therefore, essentially an analysis of historical data.
C4.2 - Earthquake Data
The daca file for the 575 years of earthquake history, on the whole, is neither sufficiently accurate nor numerically complete enougn to be subjected to statistical analysis. It
was, therefore, necessary to select within that historical
period a time interval which could be considered as the best representative sample of the current seismic activity. The
more modern events confirmed by instrumental recordings from either local or foreign seismic stations during the period 
from 1875 to 1974 were- considered scientifically reliable and were used as the basis for the evaluation of seismicity of Ethiopia. Plate C-5, Figure 3, shows the location of all
seismic events that can be assigned reliable geographic coor dinates with enough accuracy. The estimated magnitudes of all the seismic events are shown on Plate C-5, Figure 4. The extent of the Aleltu Basin is also shown on these location maps. The Aleltu Basin is along the margin of the Rift System where largest number of epicenters and volcanoes are located.
Gouin,  P.,  "Earthquake History Africa," Publication  No.  118e, Research Centre, Canada, 1977.
of     Ethiopia     and     tne     Horn     of International DevelopmentC-17
C4.3 - Evaluation Methods
(a)       Summary
The seismicity distribution over the country was
obtained by summing up and contouring the amplitudes experienced at a series of selected reference points distributed over Ethiopia. A total of 650 reference
points formed the grid. For each point on the grid, the amplitudes experienced from each seismic event regis tered for the period from 1875 to 1974 were computed in terms of intensities and ground accelerations. Inten sities are given in modified Mercalli (MM) units and the ground accelerations in percentage of the standard gra vitational acceleration, g. The predicted acceleration 
and intensity values were plotted on the base map and then contoured as shown on Plate C-5, Figures 6 and 7.
(b)       Attenuation
Computation of intensity from independent seismic events requires attenuation characteristics of the site, i.e., 
how the intensity of the resulting ground motion decreases with distance from the origin of an earth-
quaxe. No quantitative measurements of ground motion in Ethiopia are availaDle to derive an attenuation rela tionship from actual measurements in the region. There fore, tne rates of attenuation were obtained by deriving quasi-equivalent geological and crustal conditions. The dominant crustal structures in Etniopia are tne rift and the plateau. A suitaole analogy of these two crustal structures occurs on the North American Continent— California on West Coast can be approximated to the tectonically disturbed rift regions of Ethiopia; andC-18
Eastern Canada to the bedding conditions under the plateau. The adopted attenuation curves for earthquakes in Ethiopia are shown on Plate C-5, Figure 5.
(c)       Acceleration and
Intensity Maps
The instrumental information from the data file provided magnitudes of earthquakes and the macroseismic evidence provided some of the intensities. The reciprocal conversion of magnitude and intensities, and the compu tation of ground accelerations make use of the following relations.
Acc = 3 
(I-j-9.66 + 1.38 M) + 4.5 for M>5
Acc
0.69
1.64 M
e_______
1.1    e
1.1 M
for M<5
i =3 Uog10 Acc + 1*5)
where
Acc      =      ground      acceleration      in      percent      of      gravity M     = magnitude of earthquake in MM units
I       = intensity
I7 = intensity produced Dy an earthquake of magnitude 7
To determine the return period or tne rate of recurrence associated with the predicted acceleration levels for each reference point, the method of extreme valueC-19
statistics was used. This method was successfully 
applied to the analysis of seismic hazards in Canada by 
Milne and Davenport in 1969. These statistics make use
of only the yearly peak amplitudes experienced at each 
reference grid point. The reason for using only one
value over a determined period of time is to filter out
the effects of foreshocks and aftershocks. In the
original computations, return periods ranging from 3 to
1,000 years have been evaluated.
Considering        the        length        of        the        sampling        interval        a        100-yr return period is considered reliable, and beyond
100 years, the maximum intensities have been checked against the data of a 575-yr data file. The predicted ground acceleration and intensity maps of Ethiopia based on a 100-yr return period are shown on Plate C-5, Figures 6 and 7.
The predicted ground acceleration and intensity for
three towns adjacent to Aleltu Basin for 100-, 200- and 300-yr return periods are summarized in Table C.l.
C4.4 - Seismicity of Aleltu Basin
The Aleltu Basin is bounded between latitudes of 9.25° and 10.00°, and longitudes of 38.75° and 39.50°. This region is along the Western Plateau and close to the "Y" intersection 
of the Red Sea, Gulf of Aden and the Etniopian rifts. The predicted ground acceleration based on a 100-yr recurrence period from Plate C-5, Figure 6, is between 5 and 10% and the intensity from Plate C-5, Figure 7, is VII to VIII. Based on averaging the values reported for the three nearby towns
Addis Ababa, Debre Bernan and Chancno——the acceleration is 10.2% for a return period of 200 years and 15.3% for a returnC-18
Eastern Canada to the bedding conditions under the plateau. The adopted attenuation curves for earthquakes in Ethiopia are shown on Plate C-5, Figure 5.
(c)       Acceleration and 
Intensity Maps
The instrumental information from the data file provided magnitudes of earthquakes and the macroseismic evidence provided some of the intensities. The reciprocal conversion of magnitude and intensities, and the compu tation of ground accelerations make use of the following relations.
Acc = 3 log1Q
 ( I -9.66-t-l. 38 M) + 4.5 for M>5
?
Acc
0.69
1.64 M
e_______
1.1    e
1.1 M
for M<5
I =3 (log^g Acc + 1.5)
where
Acc      =      ground      acceleration      in      percent      of      gravity M     = magnitude of earthquake in MM units
I       = intensity
I7      =      intensity      produced      Dy      an      earthquake      of magnitude 7
To determine the return period or the rate of recurrence associated with tne predicted acceleration levels for each reference point, the method of extreme valueC-19
statistics was used. This method was successfully 
applied to the analysis of seismic hazards in Canada by 
Milne and Davenport in 1969. These statistics make use
of only the yearly peak amplitudes experienced at each 
reference grid point. The reason for using only one
value over a determined period of time is to filter out
the effects of foreshocks and aftershocks. In the
original computations, return periods ranging from 3 to 
1,000 years have been evaluated.
Considering        the        length        of        the        sampling        interval        a        100-yr return period is considered reliable, and beyond
100 years, the maximum intensities have been checked against the data of a 575-yr data file. The predicted ground acceleration and intensity maps of Ethiopia based on a 100-yr return period are shown on Plate C-5, Figures 6 and 7.
The predicted ground acceleration and intensity for three towns adjacent to Aleltu Basin for 100-, 200- and 300-yr return periods are summarized in Table C.l.
C4.4 - Seismicity of Aleltu Basin
The Aleltu Basin is bounded between latitudes of 9.25° and 10.00°, and longitudes of 38.75° and 39.50°. This region is along the Western Plateau and close to the "Y" intersection 
of the Red Sea, Gulf of Aden and the Etniopian rifts. The predicted ground acceleration based on a 100-yr recurrence period from Plate C-5, Figure 6, is between 5 and 10% and the intensity from Plate C—5, Figure 7, is VII to VIII. Based on averaging the values reported for the three nearDy towns
Addis Ababa, Debre Berhan and Chancho——the acceleration is 10.2% for a return period of 200 years and 15.3% for a returnC-20
TABLE C.1
EARTHQUAKE INTENSITIES Coordinates (° )
Return Period (yr)
100         200
300
Location
North     East
I*    A**   I*       A**    I*     A*w
Addis Ababa
9.00
38.77
VII
6.9
VIII
13.3
VIII
20.0
Debre Berhan
9.30
39.30
VII
5.3
VIII
9.7
VIII
14.0
Chancho
9.32
38.73
VII
4.7
VII
8.5
VIII
12.0
Average
9.15 to
38.75 to
VII
5.6
VII to VIII
10.2
VIII
15.3
estimated
10.00
39.50
for Aleltu
♦ I = MM intensities
* A = Ground acceleration as percent of standard
W
gravitational acceleration
gC-21
period of 300 years. The corresponding intensities of earthquake vary from MM index VII to VIII or a Richter magnitude of 6. A 300-yr life span appears to be reasonable for the major dam and other water conveyance structures of Aleltu. Therefore, a design acceleration of 15% correspond ing to an event with a return period of 300 years was considered appropriate to the present level of study.
C5 - SOILS AND MATERIALS
INVESTIGATIONS
C5.1 - Test Pits and 
Auger Holes
To determine the nature, depth and extent of overburden, a total of 14 test pits were excavated at tne damsites: 5 at Tiliku Aleltu, 6 at Jida and 3 at Tinishu Aleltu (see
Plates C-l, C-2 and C-6). It is noted that test pits were excavated at the Tinishu Aleltu damsite wnile reconnaissance studies continued. Eventually, as reported in Section 2, the Tinishu Aleltu scheme was eventually eliminated. In addi tion, a total of 6 test pits and 3 auger holes were completed in the potential Jima impervious borrow area, as shown on Plate C-6. The test pits were manually excavated to a depth of 3 to 4 m with shovel and picks. The nand auger holes were drilled to a maximum depth of 3 m. In many instances, hand auger holes were drilled at the bottom of the test pits to extend the depth of investigation.C-22
All the test pits were excavated without any snoring or
temporary supports. All test pits were left open for more
than a month and groundwater levels were monitored. Tension 
cracks and minor caving of walls were observed in general in 
tne test pits at impervious borrow area.
Pocket penetrometer readings were taken at regular intervals. 
As the materials encountered in impervious borrow areas were
generally homogeneous without any lenses or stratification, 
sampling was confined mostly to bulk channel samples. 
Description of the soil and the types of samples taken are
given in test pit reports, Section C5.3.
C5.2 - Laporatory Testing
Materials testing facilities at EELPA and University of Addis
Aoaba were utilized for performing the limited numoer of
routine and specialized strength and consolidation tests.
The      details      of      tests      carried      out      on      selected      samples      from      the damsite and impervious borrow area are as follows.
Type of Tests
(a) Damsite
Specific gravity
Natural moisture content tests Atterberg consistency limit tests Grain size analyses
(b) Impervious Borrow Area
Natural moisture content tests Atterberg consistency limit testsC-23
Grain size analyses
Standard Proctor compaction tests
Undrained strength tests
Swelling pressure tests
Consolidation tests
Direct shear tests
All tests were performed in accordance with ASTM Standards. The results of all tests performed on impervious material are summarized on Plate C-7.
C5.3 - Test Pit Reports Definitions
Location        and elevation
Datum
Depth
Sample number
Elevation and location of test pits
and boreholes were determined by 
precise leveling and horizontal
distance measurement. All measure
ments are based on control points
established at Tiliku Aleltu and 
Robi Jida damsites.
All       elevations       refer       to       mean       sea level (MSL) as datum.
All      depths      are      given      in      metres, measured from the ground surface.
Samples are numbered numerically in tne order in wmch they were obtained, except where noted.C-22
All the test pits were excavated without any shoring or temporary supports. All test pits were left open for more
than a month and groundwater levels were monitored. Tension cracks and minor caving of walls were observed in general in the test pits at impervious borrow area.
Pocket penetrometer readings were taken at regular intervals. As the materials encountered in impervious borrow areas were generally homogeneous without any lenses or stratification, sampling was confined mostly to bulk channel samples. Description of the soil and the types of samples taken are given in test pit reports, Section C5.3.
C5.2 - Laboratory Testing
Materials testing facilities at EELPA and University of Addis Ababa were utilized for performing the limited numDer of routine and specialized strength and consolidation tests.
The details of tests carried out on selected samples from the damsite and           impervious         borrow area are as follows.
Type of Tests
(a) Damsite
Specific gravity
Natural moisture content tests Atterberg consistency limit tests Grain size analyses
(p) Impervious Borrow Area
Natural moisture content tests Atterberg consistency limit testsGrain size analyses
Standard Proctor compaction tests
Undrained strength tests
Swelling pressure tests
Consolidation tests
Direct shear tests
All tests were performed in accordance with ASTM Standards. The results of all tests performed on impervious material are summarized on Plate C-7.
C5.3 - Test Pit Reports Definitions
Location and elevation
Datum
Depth
Sample number
Elevation and location of test pits
and boreholes were determined by 
precise leveling and horizontal
distance measurement. All measure
ments are based on control points established at Tiliku Aleltu and 
Robi Jida damsites.
All   elevations            refer       to mean sea level (MSL) as   datum.
All   depths are           given       in metres, measured from tne ground surface.
Samples are numbered numerically in tne order in which they were obtained, except where noted.C-24
Sample      type
Sample     size
Sample retained
Soil type
Indicated by two letters, the first
of these describes the sampling method and the second, the shipping container.
Dimension in millimetres and refers to the nominal diameter of the sample.
Indicates the length in millimetres of sample retained in the sampler. If no value is indicated, no recovery of sample is assumed.
Approximate composition of soil is expressed according to the following weight-percent relationship.
Silt and clay
Silty clay
Clay with some
silt
Clay witn trace
45 to 50% silt 45   to    50%  clay 25    to   45%  silt 55   to    75%  clay 10   to    25%  silt 75   to    90%  clay
<10%      silt
of silt
Clays and Silts
Consistency
Very soft
Soft
Medium soft
>90% clay
Consistency 
of
clays and silts
Unconfined
Compressive
Strength
(xg.m/cm )
<0.25
0.25 to 0.50
0.50 to 1.00
2C-25
Consistency of
clays         and         silts (cont)
Soil plasticity
Clays         and         Silts Consistency
Stiff
Very stiff Hard
Description
Unconf        ined Compressive Strength 
2
(kg.m/cm )
1.00 to 2.00
2.00 to 4.00 
>4.00
Plasticity Index (PI)
Nonplastic
0 to
4
Slightly plastic
4 to
15
Medium plastic
15 to
30
Hignly plastic
>30
Grain size
Description
distribution
Particle Size
(mm)
Boulder
305.000
or
more
Cobble
76.000
to
305.000
Coarse gravel
19.000
to
76.000
Fine gravel
4.760
to
19.000
Coarse sand
2.000
to
4.760
Medium sand
0.420
to
2.000
Fine sand
0.074
to
0.420
Silts and clays
<0.074
Grain size of rocks
Description
Very coarse grained
Coarse grained
Grain Size
(mm)
>60.000
2.000 to 60.000C-24
Sample type
Sample size
Sample retained
Soil type
Indicated by two letters, the first
of these describes the sampling method and the second, the shipping container.
Dimension in millimetres and refers to the nominal diameter of the sample.
Indicates the length in millimetres of sample retained in the sampler. If no value is indicated, no recovery of sample is assumed.
Approximate composition of soil is expressed according to the following weight-percent relationship.
Consistency           of clays and silts
Silt and clay
Silty clay
Clay with some
silt
Clay with trace
of silt
Clays       and       Silts Consistency
Very soft Soft Medium soft
45 to 50% silt 45    to   50%  clay 25    to   45%  silt 55   to    75%  clay 10   to    25%  silt
75   to    90%  clay <10%      silt
>9G% clay
Unconfined Compressive Strength
2
(kg.m/cm )
<0. 25
0.25 to 0.50 0.50 to 1.00C-25
Consistency of
clays and silts
Clays       and 
Silts
(cont)
Consistency
Unconfined Compressive Strength 
Soil plasticity
Grain size distribution
Grain size of rocks
Stiff
Very stiff Hard
Description
Nonplastic Slightly plastic Medium plastic Highly plastic
Description
Boulder Cobble Coarse gravel
Fine gravel Coarse sand
Medium sand Fine sand
Silts and clays Description
Very coarse grained
Coarse grained
2
(kg.m/cm )
1.00 to 2.00
2.00 to 4.00
>4.00
Plasticity
Index (PI)
0 to 4
4 to 15
15 to 30
>30
Particle Size
(mm)
305.000 or more
76.000 to 305.000
19.000 to 76.000
4.760 to 19.000
2.000 to 
0.420 to 
0.074 to 
<0.074
Grain Size
(mm)
>60.000
2.000 to 60.000
4.760
2.000
0.420Grain       size       of      rocks (cont)
C-26 Description
Grain Size (mm)
Medium grained Fine grained 
Very fin
e
0.060 to 2.000
0.002 to 0.060 
<0.002
grain
ed
Discontinuity 
characteristics
Spacing 
Bedding
Jointing
(mm)
0 to 1
1 to 10
10 to
100
100 to
>1,000
Very thinly
laminated
Thinly to 
thickly
laminated
Very thin 
to thinly
Dedded
Medium
Dedded
Thick
Dedded
Very close to close
jointed Medium 1,000 
jointed Wide jointed
Weathering Grades
Fresh
No visible sign of rock 
weathering. 
Rock rings under hammer line.
if crystal-C-27
Faintly weathered                     Discoloration of major discontinui ties. Rock rings under hammer if crystalline.
Slightly weathered                   Discoloration of rock and discon tinuities. Rock has dull or clunk sound under hammer and is somewhat weaker than fresh rock.
Moderately weathered
Highly weathered
• Less than 50% of rock decomposed or disintegrated to soil. Fresh or discolored rock present either as continuous framework or as core
stones.
Greater than 50% of rock decomposed or disintegrated to soil. Fresh or discolored rock present either as continuous framework or as core stones.
Completely 
weathered
One hundred percent of rock decomposed or disintegrated to soil;
original rock structure remains.
Residual soil
All rock converted to soil;
original structure destroyed.
Rock Strength Very strong
Cannot be scratched with knife. More than one blow of hammer required to break sample.Grain      size      of      rocks (cont)
Discontinuity
characteristics
C-26 Description
Medium grained Fine grained Very fine
grained Spacing Bedding (mm)
0 to 1
Grain Size
(mm)
0.060 to 2.000 0.002 to 0.060 
<0.002 Jointing
Very thinly laminated
1 to 10
10 to 100
100 to >1,000
Thinly to thickly laminated
Very thin to tninly oedded
Medium Dedded
Thick Dedded
Very close to close
jointed Medium 1,000 
jointed Wide jointed
Weathering Grades Fresh
No visible sign of rock weathering. Rock rings under nammer if crystal line.C-27
Faintly weathered
Slightly weathered
Moderately weathered
Highly weathered
Discoloration of major discontinui
ties. Rock rings under hammer if crystalline.
Discoloration of rock and discon tinuities. Rock has dull or clunk 
sound under hammer and is somewhat weaker than fresh rock.
- Less than 50% of rock decomposed or disintegrated to soil. Fresh or discolored rock present either as continuous framework or as core
stones.
Greater than 50% of rock decomposed or disintegrated to soil. Fresh or discolored rock present either as continuous framework or as core stones.
Completely 
weathered
One hundred percent of rock decomposed or disintegrated to soil;
original rock structure remains.
Residual soil
All rock converted to soil;
original structure destroyed.
Rock Strength Very strong
Cannot be scratched with knife. More than one blow of hammer required to break sample.C-28
Strong
Moderately strong
Moderately weak
Can be scratched with knife with difficulty. Can De broken with one hammer blow.
Can be scratched easily with knife;
5-mm indentations with blow of sharp pick.
Can De gouged with knife; 2-mm
indentations by firm pressure of
Weak
Very weaK rock or
hard soil
sharp pick.
Crumbles under blows of sharp pick. Can be scratched with fingernail;
may be broken in nand with 
difficulty.Test Pit Report
JOB p6888
PIT TAD-1 SHEET 1 OF 2
CLIENT Ethiopian Electric Light and Power Authority (EELPA) PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu CONTRACTOR       Local labor METHOD  OF
Hand dug with shovel and Sunny and clear
Geology pick
SITE Tiliku Aleltu - Left Bank Drawing DEPARTURE
STARTED 12:00                26/10/83
EXCAVATION
WEATHER
ELEVATIONS: DATUM MSL GROUND SURFACE 2,587.46 ROCK SURFACE Not encountered
TRENCH LENGTH          2.0
FINISHED 10:00 TEMPERATURE
BOTTOM OF PIT
1/11/83 2,583-26
WATER LEVEL Not encountered
WIDTH           2.0 
DEPTH
4.2
OEPTH SOIL TYPE                   DESCRIPTION
0.00  Silty clay Reddish brown silty clay with
with sand and cobbles
some sand and subangular to sub- rounded cobbles up to 15 cm in size, hard becoming very stiff with depth, greasy to gritty texture, heterogenous, moist, highly plastic, slight organic
odor and organic roots to 0.3m
SAMPLE
•TYPE NO. SIZE DEPTH qu_
(mm)       (m) GS                 1           Bulk         0.20
to 0.55
GQ                 2            Bulk         0.30 to 1.00
GQ                 3           Bulk         1.00 to 2.00
GS                 4           Bulk
0.55 to
0.90
GS                 5            Bulk        0.90 
to
2.70
0.50               4.5+
to
to
1.00
3.75
1.50
3.6
to
to
2.00
3.8
2.50
3.8
to
to
3.00
3.6
sampling methoo
•g _ thin wall tuoe
G — snoval
rt — carved Oioc*
INSPECTOR _Sevoum
SHIPPING CONTAINER
0 — tuoe
P — tin
Q — glass jar
S — piartic jag
T - metal can
U — woocin oox
GQ                6           Bulk         2.00
to
3.00
QU   unconfined comore^sive strength
in Kg/cm* measured with oocKet oenatromexer
A — doth bag                Z — discarded
Lemina
L0GGED P- Valliappan, Said Mohammed
APPROVED DATE
Form 314 A 1tt Test Pit Report
JOB P6888 PIT TAD-1 SHEET 1 OF 2
CLIENT Ethiopian Electric Light and Power Authority (EELPA) PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu Geology Drawing CONTRACTOR Local labor
METHOD OF
EXCAVATION Hand dug with shovel and pick WEATHER             Sunny and clear ELEVATIONS: DATUM MSL
GROUND SURFACE 2,587.46 ROCK SURFACE Not encountered
SITE Tiliku Aleltu - Left Bank DEPARTURE
STARTED 12:00  26/10/83
FINISHED 10:00 
TEMPERATURE
1/11/83
BOTTOM OF PIT              2,583.26 WATER LEVEL Not encountered
TRENCH LENGTH 2.0
WIDTH 2.0
DEPTH 4-2 SAMPLE
DEPTH        SOIL TYPE           DESCRIPTION
0.00                   Silty clay           Reddish brown silty clay with with sand            some sand and subangular to sub-
and cobbles        rounded cobbles up to 15 cm in size, hard becoming very stiff with depth, greasy to gritty texture, heterogenous, moist. highly plastic, slight organic odor and organic roots to
0.3 m
•TYPE          NO.         SIZE       DEPTH        Tt
(mm)
(m)
GS                 1            Bulk       0.20 to 0.55
GQ                 2             Bulk       0.30 to 1.00
GQ                 3             Bulk       1.00 to 2.00
GS                 4             Bulk
0.55 
to
0.90
GS                 5             Bulk       0.90 
to
2.70
0.50                   4.5*
to
to
1.00 3.75
1.50                3.6
to
to
2.00
3.8
2.50
3.8
to
to
3.00
3.6
GQ                6             Bulk       2.00 to 3.00
sampling method
SHIPPING CONTAINER
_ thin wall tuoa G - snoval
□ - xuoa
P — xin
s-
T-
PKSXIC
nrwxai can
H — arvea oiocx
qu unconf mao comoressve srrongrh
• n Kg, cm^ maasuraa wixh oocxax panaxromexar
Q - glass gar
A — aoxn oag
U-
z -
wooaan box
discaroaa
imspfcTOR
Seyoum
Lemma
LOGGED P. Valliappan, Said Mohammed
Form 31 4 A liTest Pit Report
job p6838
PIT TAD-1
SHEET 2 OF 2
SAMPLE
DEPTH          SOIL TYPE            DESCRIPTION
3.00                     Silty clay            Yellowish brown silty clay with some fine to medium sand size particles, hard, greasy to
gritty texture, homogenous, highly plastic (residual soil derived from weathering of basalt)
•TYPE         NO.         SIZE      DEPTH       qu_
imml
(m)
3.50                 4.5* GS                7            Bulk       2.70
to 4.20
GQ               8            Bulk       3.00 to 4.00
4.20 
Bottom of test pit
Note:           1 - The walls of the pit were stable and almost ver tide.
2 - No sign of any collapse of the walls observed during logging on November 30, 1983.
Form 314 A 2‘■
Test Pit Report
CLIENT       Ethiopian       Electric       Light       and       Power       Authority PROJECT Aleltu Hydro Project
LOCATION     LATITUDE     See     Tiliku     Aleltu     Geology     Drawing CONTRACTOR Local labor
METHOD OF
JOB P6888 
PIT TAD-2
SHEET 1 OF 2
(EELPA)
SITE     Tiliku     Aleltu     -     Left     Bank DEPARTURE
STARTED        15:40        28/10/83
EXCAVATION WEATHER
Hand     dug     with     shovel     and     pick,     and     hand auger
Sunny and clear
2/11/83
ELEVATIONS: DATUM
GROUND SURFACE
MSL
2,578.13
FINISHED 09:30 TEMPERATURE BOTTOM OF PIT 2,571.76 WATER LEVEL See Note 3
ROCK SURFACE                2,574.83 TRENCH LENGTH 2.00
WIDTH 2.00
DEPTH 4.0 (test pit)
4.00 to 6.37 (auger hole) SAMPLE
DEPTH       SOIL TYPE         DESCRIPTION
•TYPE        NO.        SIZE       DEPTH       qu
0.00                    Silty clay     Dark brown grading to dark gray silty clay with trace of sub- rounded gravel and cobbles of basaltic composition up to
10 cm in size, hard becoming very stiff with depth, greasy to gritty texture, heterogenous, moist, medium to highly plastic, slight organic odor and organic roots to 0.3 m
3.30             Weathered             Light to yellowish brown basalt
basalt
moderately weak to weak, com- pletely weathered with frag ments of moderately strong basalt up to 15 cm m size
(mm/      (m)
GQ               1           Bulk      0.30
to
1.00
GS               2            Bulk      0.30
to
1.60
0.50             4.5*
1.00             3.3
1.50             3.3
2.00              3.3
2.50             2.7
3.00             2.6 GS                3           Bulk       1.60
to 3.00
GQ               4           Bulk       2.00 to 3.00
GS               5           Bulk       3.30 to
4.00
SAMPLING METHOO
SHIPPING CONTAINER
•9 — thin wall tub®
G - sftove*
H — carvea diock
0 - tuoa
P — tin
□ - giau jar
R - ciotn bag
s -   pianic
T -    merai an
U - woocen pox
z -   dijcaraea
qu uncontmea compressive strtngtn
n «cg/cm“ measured with pocket penetrometer
imsppctor Seyoum            Lemma
AP°ROVED
-
uOGGED p, Valliappan, Said Mohammed
° ATc Pecember" •___________________________________
Corm 314 m 11Test Pit Report
J0B P6888
PIT TAD-1
SHEET 2 OF 2
SAMPLE
DEPTH          SOIL TYPE            DESCRIPTION
3.00                     Silty clay            Yellowish brown silty clay with some fine to medium sand size particles, hard, greasy to
gritty texture, homogenous, highly plastic (residual soil derived from weathering of basalt)
•TYPE         NO.         SIZE (mm)
DEPTH (m)
qu_
3.50                 4.5+ GS                7            Bulk       2.70
to 4.20
GQ               8            Bulk       3.00 to 4.00
4.20
Bottom of test pit
Note:                  1 - The walls          of the pit were stable and almost verticle.
2 - No sign of any collapse of the walls observed during logging on November 30, 1983.
Form 314 A 12Test Pit Report
CLIENT        Ethiopian        Electric        Light        and        Power        Authority PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu Geology Drawing
CONTRACTOR
METHOO OF EXCAVATION
Local labor
Hand  dug  with  shovel and  pick, and  hand 
JOB P6888
PIT TAD-2
SHEET 1 OF 2
(EELPA)
SITE Tiliku Aleltu - Left Bank DEPARTURE
started         15:40        28/10/83
FINISHED
09:30           2/11/83
weather
auqer
Sunny
and clear
ELEVATIONS; DATUM       MSL GROUND SURFACE           2,578.13 ROCK SURFACE                 2,574.83
TRENCH LENGTH
2.00
WIOTH 2.00
TEMPERATURE BOTTOM OF PIT 2,571.76 WATER LEVEL See Note 3
DEPTH 4.0 (test pit)
4.00 to 6.37 (auqer hole) SAMPLE
DEPTH       SOIL TYPE          DESCRIPTION
0.00                     Silty clay     Dark brown grading to dark gray silty clay with trace of sub- rounded gravel and cobbles of basaltic composition up to
10 cm in size, hard becoming very stiff with depth, greasy to gritty texture, heterogenous, moist, medium to highly plastic, slight organic odor and organic roots to 0.3 m
•TYPE        NO.         SIZE (mm;
DEPTH (m)
qu.
3.30           Weathered             Light to yellowish brown basalt
basalt
moderately weak to weak, com- pletely weathered with frag- ments of moderately strong basalt up to 15 cm in size
GQ               1          Bulk       0.30
to
1.00
GS                2           Bulk       0.30
to
1.60
0.50               4.5* 1.00               3.3
1.50               3.3
2.00               3.3
2.50              2.7
3.00               2.6 GS                3          Bulk        1.60
to 3.00
GO               4          Bulk        2.00 to 3.00
GS                5           Bulk        2.30 to
4.00
SAMPLING    method
SHIPPING CONTAINER
•g — trim wall tune
G - snovei
rt - arvea     OIOCM
INSPECTOR Seyoum Lemma
0 - tuo«
P — rm
Q - glass jar
S — plastic oaq
T — metai can
U - woooen sox
qu unconti
compressive strength
m Kg . cm2     measu re a with pocKet penetrometer
R — doth oag                Z - discaraea
a 4 \ APPROV=D     ^1A vl
r
LOGGED      P. ValliaDpan. Said Mohammed 
DATE Decemhp^ IQTest Pit Report
DEPTH        SOIL TYPE DESCRIPTION
JOB P6888
PIT TAD-2 SHEET 2 OF 2
SAMPLE________________________ -TYPE NO. SIZE DEPTH
Imm) (m)
qu
6.37 
Bottom of test pit
No te: 1  - Hole advanced with auger below 4.0 m.
2   - Observed tension cracks and caving of walls to 3.0 m during logging on November 30, 1983.
3   - Water levels in test pit and auger hole.
Date
Depth
2/11/83
3/11/83
4/11/83 
14/11/83
30/11/83
(m)
6.00 5.33
5.17
5.17
5.50
i
^orm 314 A 2'a
Test Pit Report
CLIENT Ethiopian Electric Light and Power Authority (EELPA) PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu Geology Drawing CONTRACTOR   Local labor
METHOD OF
EXCAVATION
Hand dug with shovel and pick
WEATHER Sunny
ELEVATIONS: DATUM
and clear
MSL
GROUND SURFACE 2,563.88
ROCK SURFACE 2,561.48
J0B psese PIT TAD-3 SHEET 1 OF 1
SITE Tiliku Aleltu - Left Bank DEPARTURE
STARTED 07:30           27/10/83
FINISHED 14:00           28/10/83 TEMPERATURE
BOTTOM OF PIT 2,563.03 WATER LEVEL Not encountered
T
RENCH LENGTH 2.00                                 WIDTH 1.50                                  DEPTH
q.85
SAMPLE
DEPTH      SOIL TYPE          DESCRIPTION
•TYPE
NO.
SIZE
DEPTH
(mml
(mJ
0.00                      Silty clay
Dark brown silty clay with trace     GZ                1           Bulk      0.00
of subrounded gravel and cobbles
of basaltic composition up to
to
0.4C
15 cm in size, greasy to gritty 
texture, heterogenous, moist,
highly plastic, slight organic
odor and organic roots to 
0.3 m
0.40 Weathered 
Dark gray fine grained
basalt
aphanitic basalt, moderately
strong to very strong, moder
ately weathered to faintly 
weathered with depth, columnar
jointed with block sizes rang
ing from 15 to 25 cm
q.85 
Bottom of test pit
Note: Unanle to dig with hand tools below 0.85 m.
sampling methoo
SH
IPPING CONTAINER
•g - mm wall tude
□ - tuoe
s -
pianic oag
qu uncon*into compressive rtrengtn
q _ snovei
P - tin
T -   metal can
m                    measured with pocket oenetrometer
M — carved Diock
Q - glass jar
U-
wooaen oox
R - clotn oag
z -
discarded
.mcpppTOR Seyoum
Lemma
APPROVED
W OGGED P. Valliappan, Said Mohammed
DATE December 1983
Form 314 A Hi»OT
Test Pit Report
JOB P6888 PIT TAD-4 SHEET 1 OF 1
CLIENT Ethiopian Electric Light and Power Authority (EELPA) PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu Geology Drawing
CONTRACTOR
METHOD OF EXCAVATION
WEATHER ELEVATIONS:
Local labor
Hand dug with shovel and pick Sunny      and clear
DATUM
MSL
GROUND SURFACE 2,567.38 ROCK SURFACE 2,567.08
TRENCH LENGTH 1-50
WIDTH 1.50
DEPTH SOIL TYPE                  DESCRIPTION
SITETiliku Aleltu - Right Bank DEPARTURE
STARTED 11:00                1/11/83
FINISHED 08:45               2/11/83 TEMPERATURE
BOTTOM OF PIT 2,566.23
WATER LEVEL Not encountered
DEPTH 1.15
SAMPLE
TYPE        NO.        SIZE       DEPTH       qu imml      ImJ
0.00              Silty clay                Dark       gray       silty       clay       with       trace of subrounded gravel and
cobbles of basaltic composition up to 15 cm in size, greasy to gritty texture, heterogenous, moist, highly plastic, slight organic odor and organic roots to 0.3 m
Weathered             Light gray fine grained basalt,
GZ               1            Bulk     0.00 to 0.30
basalt
1.15
vesicular with vesicles par tially filled with white zeo- litic minerals, moderately strong becoming strong with depth, slightly weathered to faintly weathered with deptn, columnar jointed with Dlock sizes ranging from 15 to 30 cm, probably top of flow covering river bed
Bottom of test pit
Note:          1  - Unable to dig with hand tools below 1.15 m. 2   - A topographical low depression exists about
20 m downstream from pit.
sampling methoc
-   thin wall tube
SHIPPING CONTAINER
-   .novel
- carved oiock
O - tube
P — tin
S — olastic oag T — metai san
qu uncontineo compressive
■n kg/cm* measured  .tn
w        pocket
strength
Q — glass jar
R — ciorh oag
U — wooden box Z — discarded
.NSPSCTOR jevc/un Lemma
APPROVED
LOGGED p. Valliappan, Said Mohammed
DATE December 198 3
Form 314 A 11co o r
Test Pit Report
CLIENT Ethiopian Electric Light and Power Authority PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu Geolooy Drawing CONTRACTOR      Local labor
METHOD OF
EXCAVATION
Hand dug with shovel and pick
WEATHER              Sunny and clear ELEVATIONS: DATUM MSL
GROUND SURFACE 2,585.40
ROCK SURFACE Not TRENCH LENGTH 2.0
encountered
WIDTH 2.0
DEPTH SOIL TYPE            DESCRIPTION
0.00            Silty clay              Dark brown silty clay with trace of sand and subangular cobbles up to 15 an in size, hard becom- ing stiff around 3.0 m and
JOB P6888
PIT TAD-5
SHEET 1 OF 2
(EELPA)
SITE Tiliku Aleltu - Right Bank DEPARTURE
STARTED        09:30 2/11/83
FINISHED        17:00 7/11/83 TEMPERATURE
BOTTOM OF PIT 2,580.70
WATER LEVEL Not encountered
DEPTH 4.7
SAMPLE
•TYPE        NO.        SIZE      OEPTH        qu
•
increasing to very stiff below, greasy to gritty texture, hete- rogenous, moist, highly plastic, slight organic odor and organic roots to 0.3 m, concentration of basaltic cobbles in places
GQ               1
GQ               2
GQ               3
GQ               4
(mm)      (m2 0.30
to 1.00 1.00 to 2.00 2.00 to 3.00 3.00 to 4.00
0.50              4.5+ 1.00            4.1
1.50            3.6
2.00            3.6
2.50            1.9
3.00            1.8 3.50            3.2 4.00            3.9
4.70
Bottom of test pit
GS                5             Bulk      0.50 to 4.50
SAMPLING METHOD
SHIPPING CONTAINER
-   tn«n wall tuoa
w - tUD*
S - oianic Dag
-   snovel
P - rm
qu unconfmaa compress>va strength
T - meiai can
-   carveo piock
Q - glass |ir
•n Kg/cm^ measured with pocKet penetrometer
U - wooden pox
R - doth oag
Z - d'jcarata
INSPECTOR Seyoum Lemma LOGGED P. Valliappan, Said Mohammed
DATE    December 1983
corm 314 A 111Test Pit Report
JOB p680e
PIT TAD-4 SHEET
CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tiliku Aleltu Geology Drawing DEPARTURE
SITETiliku Aleltu - Right Bank
CONTRACTOR
METHOD OF
EXCAVATION
Local labor
Hand dug with shovel and pick
STARTED
FINISHED
11:00
08:45
1/11/83
2/11/83
WEATHER               Sunny     and clear
ELEVATIONS:   DATUM
MSL
GROUND SURFACE 2,567.38 ROCK SURFACE 2,567.08
TRENCH  LENGTH 1.50
WIDTH 1.50
OEPTH        SOIL TYPE           DESCRIPTION
TEMPERATURE
BOTTOM OF PIT 2,566.23 WATER LEVEL Not encountered
DEPTH 1.15
SAMPLE
•TYPE        NO         SIZE      DEPTH
(mm J
0.00
Silty clay
Dark gray silty clay with trace
GZ
1
Bulk
of subrounded gravel and
cobbles of basaltic composition 
up to 15 cm in size, greasy to 
gritty texture, heterogenous,
0.30
moist, highly plastic, slight organic odor and organic roots to 0.3 m
Weathered            Light gray fine grained basalt,
basalt
1.15
Note: 1
vesicular with vesicles par tially filled with white zeo- litic minerals, moderately strong becoming strong with depth, slightly weathered to faintly weathered with depth, columnar jointed with block sizes ranging from 15 to 30 cm, probably top of flow covering river bed
3ottom of test pit
-   Unable to dig with hand tools below 1.15 m.
2   -   A topographical low depression exists about 20   m  downstream from pit.
SAMPLING METHOD
*B - thin «ail tube
G — snovai
m — carvao oiock
SHIPPING CONTAINER
O — ruD«
P — tin
a — glass |ir
R — cloth nag
S
T
U
z
piastre Dag
marai can
woooan dox
discaroao
□ nconr.naa comprewve srrengtn
n 'naawrto w.th pockat panatromatar
INSPECTOR
Sevoum Lemma
LOGGED p. Valliappan, Said Mohammed
APPROVED DATE
Form 314 A 11 lTest Pit Report
JOB P6888 PIT TAD-5 SHEET 1 OF 2
CLIENT
Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION   LATITUDE See Tiliku Aleltu Geolocry Drawing DEPARTURE CONTRACTOR      Local labor
METHOO OF
EXCAVATION
Hand dug with shovel and pick
STARTED
FINISHED
SITE Tiliku Aleltu - Right Bank 09:30         2/11/83
17:00        7/11/83
WEATHER             Sunny and clear ELEVATIONS: DATUM MSL
GROUND SURFACE 2,585.40 ROCK SURFACE Not encountered
TRENCH LENGTH      2.0
TEMPERATURE
BOTTOM OF PIT 2,580.70 WATER LEVEL Not encountered
WIDTH
2.0
DEPTH
4.7
DEPTH      SOIL TYPE
SAMPLE
•TYPE        NO.        SIZE      OEPTH       51 imml
(m?
0.00
Silty       clay
DESCRIPTION
Dark brown silty clay with trace of sand and subangular cobbles up to 15 cm in size, hard becom- ing stiff around 3.0 m and increasing to very stiff below. greasy to gritty texture, hete- rogenous, moist, highly plastic, slight organic odor and organic roots to 0.3 m, concentration
of basaltic cobbles in places
GQ               1
GQ               2
GQ               3
GQ               4
0.30
to
1.00
1.00
to
2.00
2.00
to
3.00
3.00
to
4.00
0.50             4.5* 1.00            4 1
1.50            3.6
2.00            3.6
2.50            1.9
3.00            1.8 3.50            3.2 4.00            3.9
4.70
Bottom of test pit
GS                5             Bulk      0.50 to 4.50
sampling
method
SHIPPING CONTAINER
*9 - thin wall tuoe
G - jfiovti
ri — carvwa oiock
INSPECTOR Spyoiim Lemma
0 - tuoe
P — tin
Q - glass jar
R - aotn bag
S - Plastic oag
T     -    metal on
wooden oox
dtscaraea
U-
qu unconfined compressive strength
in <g/cm^ measurea with pocxet penetrometer
z -
APPROVED
LOGGED
P. Valliappan, Said Mohammed
Form 314 A 1SAMPLE
DEPTH SOIL TYPE DESCRIPTION
Note:          1 - The walls of the test pit were stable
and almost verticle.
2              - No sign of any collapse of the walls ODserved during logging on November 30, 1983.
TYPE        NO.         SIZE (mm/
DEPTH (m)
Form 314 A i2Test Pit Report
JOB P6888 PIT TINAD-1 SHEET 1 OF 1
CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tinishu Aleltu Geology Drawing DEPARTURE CONTRACTOR Local labor
METHOD OF
EXCAVATION   Hand dug with shovel and pick WEATHER          Sunny and clear ELEVATIONS: DATUM        MSL
GROUND SURFACE ROCK SURFACE
TRENCH LENGTH 2.0
2,592.77
2,591.97
SITE Tinishu Aleltu - Right Bank STARTED 09:00              15/11/83
FINISHED 15:30             16/11/83 TEMPERATURE
BOTTOM OF PIT 2,591.57 WATER LEVEL Not encountered
WIDTH 2.0
DEPTH 1>2
DEPTH      SOIL TYPE         DESCRIPTION
0.00                      Silty clay     Dark reddish brown silty clay with trace of coarse sand and subangular basalt fragments up to 10 cm in size, hard, floury to gritty texture, hete- rogenous, moist, highly plastic, slight organic odor and organic
roots to 0.3 m, sand and
SAMPLE
*TYPE        NO.        SIZE       DEPTH       qu
Imml      (mJ
GQ               1           Bulk      0.20
to
0.80
GS               2            Bulk      0.20
to
0.80
0.50                4.5 0.80                4.1
cobble
content
increases
toward 
bottom
(soil
mainly 
transported 
talus)
0.80 Weathered Dark gray basalt, medium grained 
basalt plagioclase crystals in a fine
grained ground mass, strong to very strong, columnar jointed and blocky at surface with average size of blocks about 15 cm, moderate to highly 
weathered
1.20
Note:
Bottom of test pit
Unable to dig with hand tools below 1.2 m.
sampling method
•g - thin wail tune
G - snovei
h - arvea oiock
SHIPPING CONTAINER
0         - tune                   S  -     oustic oaq
P        - tin                      T  -      metal an
Q - gnu tar U - wooden box
R         - clothoag           Z  -     □ uaraea
inspector           Sevoum     ■ueimna LOGGED p. Valliappan, Said Mohammed
qu unconfineo compressive strength
■n Kg/cm^ measured with pocket penetrometer
APPROVED
OATE December TL983
Form 314 A 11Test Pit Report
P6888 JOB
PIT TINAD-2
SHEET 1 OF 2
CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tinishu Aleltu Geology Drawing DEPARTURE
CONTRACTOR    Local labor METHOD OF
SITE Timshu Aleltu - Right
Bank
EXCAVATION
WEATHER
Hand dug with shovel and and clear
Sunny
pick
ELEVATIONS.  DATUM    MSL GROUND SURFACE        2,591.82 ROCK SURFACE             2,590.37
STARTED 09:00
FINISHED 08:30
TEMPERATURE BOTTOM OF PIT WATER LEVEL
15/11/83 17/11/83
2,589.82
1.50 
(see Note 4)
TRENCH  LENGTH
2.0
WIDTH
2.0
DEPTH
2.0
SAMPLE
DEPTH
SOIL TYPE
DESCRIPTION
•TYPE
NO.
SIZE
Immi
OEPTH
Im)
qu
0.00
Silty clay
Dark gray silty clay with trace
GQ
1
Bulk
0.20
of coarse sand and subrounded
to
gravel up to 3 cm in size, very
1.00
stiff to hard, floury to gritty
GS
1
Bulk
0.20
texture, heterogenous, moist, highlv plastic, slight organic odor and organic roots to 0.3 m
(soil mainly transported talus)
1.00             Cobbly                   Transported talus with subrounded clay with                cobble size basalt fragments in sand and                 a matrix of dark gray silty clay grave 1                   with some sand and gravel size
particles, hard, floury to gran ular texture, heterogenous, moist, necoming wet with depth, medium plastic
to 1.00 0.50 1.00
3.75
2.50
1.45
Weathered basalt
METHOD
Brownish gray, fine grained, moderately weak to strong, highly weathered, stained along fracture surfaces, blocky along surface with block sizes ranging from 3 to 20 cm with an 
size around 6 cm
Bottom       of       test       pit
SHIPPING CONTAINER
average
2.00
sampling
*9 - thin wall tuoa
G - snovai
H - arj»d oiock
INSPECTOR Seyoum
0 — tuM
P - tin
Q - giass i«r
R - cloth oaq
S
T
U
z
□u unconfin«a compr«uiVt nrengxn
kJ, cm* m..,urla w„„ Docl<„
Lemma
APPROVED ^J,l DATE December "1983
'z
LOGGED
P.    Valliappan, Said Mohammed
Form 314 A■
Test Pit Report
JOB P6888 PIT TINAD-2 SHEET 2 OF 2
depth so
il type de
scription
SAMPLE______________________ -TYPE NO SIZE DEPTH
qu
Imm) (m)
Note:
1 - Unable t
o excavate below 2
.0 m because
of
seepage      and 
accumulation 
of
ground
water.
2              - Weathered basalt appears to be highly permeable and the water accumulated in the pit is clear.
3  - Pit appears to be stable and no sign of caving of wall observable.
4  - Water levels in test pit. Date                Depth
(m)
16/11/83
17/11/83
23/11/83
1.50
1.57
1.55CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tinishu Aleltu Geolocy Drawing DEPARTURE CONTRACTOR      Local labor
METHOO  OF
SITE Tinishu Aleltu - Left Bank STARTED         09:00          15/11/83
EXCAVATION WEATHER
Hand      dug      with      shovel      and      pick Sunny and clear
16/11/83
elevations. OATUM           MSL
FINISHED 15:15 TEMPERATURE BOTTOM OF PIT 2,589.97
GROUND SURFACE ROCK SURFACE
TRENCH LENGTH 2.0
2,591.17
2,590.07
WIDTH 2.0
WATER       LEVEL       1.15       (15/11/83       and 23/11/83)
DEPTH 1.2
SAMPLE
DEPTH
SOIL TYPE
DESCRIPTION
•TYPE
NO.
SIZE
(mm)
DEPTH
0.00
Silty clay
Yellowish gray becomina reddish
GQ
1
Bulk
0.20
with sand and cobbles
brown with depth, silty clay with some sand and subangular cobbles of basalt, hard, floury to gritty texture, neterogenous, moist becoming wet with deptn, medium plastic, slight organic odor and organic roots to
0.2 m
to 1.00
GS                1            Bulk       0.20 to 1.00
0.50
0.70              Silty clay                 Dark gray silty clay with trace
of medium to coarse sand, stiff,
floury to gritty texture, homo-
genous,       wet,       medium       to       highly plastic, slight organic odor
1.00
1.10              Weathered basalt
1.20
Dark gray basalt, strong to very strong, columnar jointed and blocky at surface with an average block size of 15 cm, faintly weathered
Bottom of test pit
Note:                       Unable to dig   with hand tools below 1.2 m.
sampling method
SHIPPING CONTAINER
’9 — thin wall tube
G - snovel
□ - ube
r
P — tin
S-
T-
piarric bag
metal can
qu uncontmea comprewve strength
h — carved mock
□ - glass iar R - cloth bag
U-
z -
wooden oox discarded
m
m..wr«a w«h pocx.t p.n.trom.«r
.NSPECTOR Sevoum Lemma
z--
LOGGED p. Valliappan, Said Mohammed
December ^983
Form 3’4 A 1Test Pit Report
JOB P6888 PIT RJD-1 SHEET 1 OF 1
CLIENT Ethiopian Electric Light PROJECT Aleltu Hydro Project LOCATION LATITUOE See Robi Jida
CONTRACTOR
METHOD OF
EXCAVATION
Local labor
Hand dug with shovel
and Power Authority (EELPA) Geology Drawing
and pick
SITE Robi Jida - DEPARTURE STARTED 08:30
FINISHED 12:30
Left Bank 4/11/83
5/11/83
WEATHER           Sunny
and clear
TEMPERATURE
ELEVATIONS: DATUM
MSL
BOTTOM OF PIT
2,573.94
GROUND SURFACE
2,575.74
WATER LEVEL
ROCK SURFACE
2,574.64
1.2 (5/11/83) Dry (29/11/83)
TRENCH LENGTH
2.0
WIDTH
2.0
OEPTH 0.00
SOIL TYPE Silty clay
DESCRIPTION
Dark brown grading to dark gray, silty clay with trace of sub-
rounded gravel and cobbles of basaltic composition up to 30 cm
in size, medium stiff, greasy
to gritty texture, heterogenous, moist, highly plastic, slignt
organic odor and organic roots
to 0.3 m
Light gray, fine grained 
DEPTH 1.8
SAMPLE
•TYPE         NO.         SIZE       DEPTH        qu
(mm)
(mJ
GO                1            Bulk       0.20 to 1.00 0.50 1.00
GS                2            Bulk       0.20 to
1.00
0.9
0.9
1.10
Weathered basalt
apnanitic, moderately
weathered,
completely
moderately weak to strong, moderately at places highly to weathered, columnar
1.80
Note:
jointed  with  block  sizes ranging from 10  to  20  cm m size, highly permeable
Bottom of test pit
1  - Groundwater started seeping from 1.2 m.
2   - Water had to be bailed out during excavation.
3  - Pit dry during logging on November 29, 1983.
4   - A spring about 30 m from the test pit possibly marking the contact between flow units of basalt.
sampling method
•3 — trim wall tuoe
G - snovei
k - carved diock
INSPECTOR Seyoum
.OGGED          P.
SHIPPING CONTAINER
0 - tuoe
S
-   aianic bag
P — tin
T
-   'natal an
□ - gnu jar
U
-   wooden oox
qu unconrjneo compressive strength
in •cg^cm* - measured with pocket penetrometer
1
A - dotn oeg
z -      disarrjea
Lemma
Valliappan, Said Mohammed
APPROVED DATE oeTest Pit Report
JOB P6888 PIT TINAD-3 SHEET 1 OF 1
CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Tinishu Aleltu Geology Drawing DEPARTURE
contractor
METHOO OF EXCAVATION
WEATHER Sunny
Local labor
Hand dug with shovel and pick and clear
SITE Timshu Aleltu - Left Bank STARTED          09:00          15/11/83
16/11/83
ELEVATIONS: DATUM GROUND SURFACE ROCK SURFACE
TRENCH LENGTH 2.0
MSL 2,591.17 2,590.07
FINISHED 15:15 TEMPERATURE BOTTOM OF PIT 2,589.97
WIDTH 2.0
DEPTH        SOIL TYPE             DESCRIPTION
0.00 Silty clay Yellowish gray becomina reddish
WATER       LEVEL       1.15       (15/11/83       and 23/11/83)
DEPTH i,2
SAMPLE
•TYPE         NO.         SIZE       DEPTH
(mm)       (m) GQ                1            Bulk       0.20
with sand and cobbles
brown with depth, silty clay with some sand and subangular cobbles of basalt, hard, floury to gritty texture, heterogenous. moist becoming wet with depth, medium plastic, slight organic odor and organic roots to
0.2 m
to 1.00
GS                 1            Bulk       0.20 to 1.00
0.50
4.30
0.70                     Silty clay            Dark gray silty clay with trace of medium to coarse sand, stiff, floury to gritty texture, homo genous, wet, medium to highly plastic, slight organic odor
1.10 Weathered Dark gray basalt, strong to very
1.00
1.55
basalt
1.20
strong, columnar jointed and blocky at surface with an average block size of 15 cm, faintly weathered
Bottom of test pit
Note:          Unable to dig with hand tools below 1.2 m.
sampling method
SHIPPING CONTAINER
*3 — thm wall tube
O
- tuo«
S-
plastic dag
qu unconfined compressive strength
G — tnovei
P
- tin
T-
metal   can
M — carv«o Slock
•n <g,cm2 measured                p.
Wl<h QOCk-t      nttrom<ttr
□
— glass jar
U—
AOOdin dox
R
- aotn oag
Z—
discarded
INSPECTOR Sevoum Lemma------------------------------------------------ LOGGED           P. ValLiapoar., Said Mohammed
Form 314 A 1)n
Test Pit Report
JOB P6888 PIT RJD-1 SHEET 1 OF 1
CLIENT Ethiopian Electric Light PROJECT Aleltu Hydro Project
and Power Authority (EELPA)
SITE Robi Jida - DEPARTURE
Left Bank
LOCATION . LATITUOE See Robi Jida                Geology Drawinq CONTRACTOR   Local labor
METHOD OF
EXCAVATION    Hand dug with shovel WEATHER           Sunny and clear ELEVATIONS: DATUM MSL
GROUND SURFACE 2,575.74 ROCK SURFACE 2,574.64
TRENCH LENGTH 2.0
and pick
STARTED 08:30               4/11/83
FINISHED 12:30              5/11/83 TEMPERATURE
BOTTOM OF PIT 2,        573.94 WATER LEVEL       1.2 (5/11/83)
Dry (29/11/83)
WIDTH 2.0
DEPTH      SOIL TYPE          DESCRIPTION
0.00                      Silty clay     Dark brown grading to dark gray. silty clay with trace of sub- rounded gravel and cobbles of basaltic composition up to 30 cm
in size, medium stiff, greasy
to gritty texture, heterogenous.
DEPTH 1.8
SAMPLE
•TYPE        NO.         SIZE       OEPTH       qu
(mm)      Im} GO                1            Bulk      0.20
to 1.00
0.50                0.9
1.00                0.9
GS                2            Bulk       0.20
moist, highly plastic, slight
to
organic odor and organic roots
1.00
to 0.3 m
1.10 Weathered Light gray, fine grained 
basalt
aphanitic, moderately weak to
moderately strong, moderately 
weathered, at places highly to 
completely weathered, columnar
jointed with block sizes ranging 
from 10 to 20 cm in size, highly 
permeable
1.80 
Bottom of test pit
Note:         1 
- Groundwater started seeping from 1.2 m.
2 
- Water had to be bailed out during excavation.
3 
- Pit dry during logging on November 29, 1983.
4 
- A spring about 30 m from the test pit possibly
marking the contact between flow units of
basalt.
SAMPLING METHOO
SH
IPPING
CONTAINER
■g — trim wall tuoe
0 - tuoe
s -
oiasxic Dag
5u unconfined compressive strengtn
3 - snovel
P - tin
T-
metal can
n - sarved oiock
<n Kg.cm^ measured with pocket penetrometer
□-
jar
U-
wooden oox
R - doth Dag
z -  discarded
incpfcTOR Seyoum          Lemma
logged ?. Valliappan, Said Mohammed
APPROVED
Da.E DecemoeY 1983Test Pit Report
JOB P6888 PIT RJD-2 SHEET 1 OF 1
CLIENT          Ethiopian Electric Light
PROJECT LOCATION
Aleltu Hydro Project LATITUDE See Robi Jida
and Power Authority (EELPA) Geology Drawing
and pick
SITE Robi Jida - DEPARTURE
CONTRACTOR        Local labor METHOD   OF
EXCAVATION
Hand dug with shovel
STARTED
FINISHED
09:00
16:00
Left Bank 3/11/83
8/11/83
WEATHER               Sunny
ELEVATIONS.
DATUM
GROUND SURFACE ROCK SURFACE
and clear MSL 2,562.89 2,561.24
TEMPERATURE
BOTTOM OF PIT 2,558.29
WATER LEVEL 4.40 (14/11/83)
3.80               (29/11/83)
See Notes 3
and 4
TRENCH   LENGTH                 2.0
WIDTH
2.0
DEPTH
SAMPLE
4.6
DEPTH 0.00
SOIL TYPE             DESCRIPTION
Silty clay                  Dark gray grading to dark brown below 1.10 m, silty clay with trace of subrounded gravel and coobles of basaltic composition up to 15 cm in size, stiff,
greasy to gritty texture, hete- rogenous, moist, medium to highly plastic, slight organic odor and organic roots to
0.3 m
Weathered                Light gray, fine grained basalt
•TYPE
NO.
SIZE
Imml
DEPTH
(m)
qu
GQ
1
Bulk
0.20
to
1.00
0.50
1.00
1.10
1.25,
GS
2
Bulk
0.20
to
1.15
1.65
GQ
3
Bulk
1.00
basalt
vesicular, moderately weak, highly to completely weathered, vesicles filled with white zeo- litic minerals, possibly top of flow, considerably weathered, highly permeable
Bottom of pit
to
2.00
GS
4
Bulk
1.15
to
1.70
4.60
Note:          1 2
The walls of the pit were stable and 
almost vertical.
No sign of any collapse of the walls observed during logging on November 29, 1983.
3   - Groundwater started seeping from 3.73 m.
4   - Water
sampling methoo
•8 — thm wall tub®
G — shovel
M — carved block
INSPECTOR Sevoum
collected in the pit is verv clear.
SHIPPING CONTAINER
□           - tube               S p          - tin                  T
Q        — glass ar
t
A          - doth bag       Z
Lemma
U•
qu unconhnea compr«uiv« strength
measured with pocxet penetrometer
APPROVED
LOGGED
P. Valliappan
Form 314 All)b
Test Pit Report
J0B 86888 PIT RJD-3 SHEET 1 OF l
CLIENT Ethiopian Electric Light and Power Authority (EELPA) PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Robi Jida Geology Drawing CONTRACTOR       Local labor
METHOD OF
EXCAVATION        Hand dug with shovel and pick WEATHER               Sunny and clear ELEVATIONS: DATUM MSL
GROUND SURFACE 2,555.52
• ROCK SURFACE          2,554.67
SITE Robi Jida - Left Bank DEPARTURE
STARTED 08:50  3/11/83
FINISHED 09:50             4/11/83 TEMPERATURE
BOTTOM OF PIT            2,554.22 WATER LEVEL 0.85 (8/11/83)
TRENCH LENGTH 2.0 
WIDTH 2.0 
DEPTH      SOIL TYPE          DESCRIPTION
0.00                 Silty clay          Dark gray silty clay with trace
of subrounded gravel and cobbles
of basaltic composition up to
30 cm in size, medium stiff,
greasy to gritty texture, hete
rogenous, moist, highly plastic,
slight organic odor and organic
roots to 0.4 m
0.85  Weathered  Light gray, fine grained  basalt
1.20 (29/11/83) OEPTH 1.3
SAMPLE
•TYPE        NO.        SIZE       DEPTH       qu
(mm/      (mJ GQ               1          Bulk      0.20
to
0.80
0.50 0.65
basalt
1.30 
with phenocrists of plagioclase, moderately weak, highly weathered becoming slightly weathered at
the bottom of the pit, highly permeable
Bottom of test pit
Note:         1 - Unable to dig with hand tools oelow 1.30 m. 2   - Water had to be bailed out during excavation. 3  - Water collected in the pit is very clear.
SAMPLING METHOD
SHIPPING CONTAINER
*8 - tnm wall tuoe
G - snovei
0 - tuoe
P - tin
H - carved oiocK
s - plastic sag
T — meta, can
U - wooden oox
Z - aucaraeo
qu unconf mea compressive strength
h Kg/cm* measure a with pocKCt penetrometer
□ - giau jar A - aotn sag
INSPECTOR Seycum Lemma
I
APPROVED
uOGG ED p. Valliappan, Said Mon amine d
□ ATP
Form 314 A > 11Test Pit Report
JOB P6888 PIT RJD-4 SHEET 1 OF 1
CLIENT          Ethiopian          Electric          Light          and          Power          Authority PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Robi Jida Geoloov Drawing CONTRACTOR         Local labor
METHOD   OF
(EELPA)
SITE Robi Jida - Right Bank DEPARTURE
STARTED 08:30 
EXCAVATION          Hand dug with shovel
and pick
10/11/83
10/11/83
WEATHER                Sunny ELEVATIONS: DATUM
GROUND SURFACE ROCK SURFACE
and          clear MSL
2,554.25 2,553.75
FINISHED 17:10 TEMPERATURE BOTTOM OF PIT 2,553.25
PIT LENGTH
2.0
WIDTH 2.0
"bEPTH        SOIL TYPE            DESCRIPTION
0.00               Silty clay                 Dark gray silty clay with trace
of subrounded gravel and cobbles of basaltic composition up to 20 cm in size, medium stiff, greasy to gritty texture, hete rogenous, moist, highly plastic, slight organic odor and organic roots co 0.3 m
0.50              Weathered Light gray# fine grained 
WATER LEVEL Not encountered DEPTH 1.0
SAMPLE_________________________
•TYPE NO. SIZE DEPTH qu
GZ                1
(mm/ (m) Bulk 0.00 
to
0.50
basalt
1.00
aphanitic with phenocrysts of plagioclase and pyroxene, moder ately weak and moderately weathered at the top becoming strong and faintly weathered at the bottom of the pit, columnar jointed with size of blocks ranging from 10 to 25 cm
Bottom of test pit
Note:          Unable to            dig with hand tools below 1.0 m.
SAMPLING METHOD
•fl - rnm wall ruM
G - tn ov«i
h - carved oiock
INSPECTOR Sevoum Lemma
SHIPPING CONTAINER
0 - tube
P — tin
Q - glass jer
A - doth oag
S - oiastic oaq
T - metal can
U - .-■'ooaen dox
Z - d scarped
Qu uncontined compressive strength
• n Kg/cm? measured with pocket penetrometer
LOGGED p. Valliappan, Said Mohammed
APPROVED DATE
\J         IQ 93
Form 3’4 A I11Test Pit Report
CLIENT Ethiopian Electric Light and Power Authority PROJECT Aleltu Hydro Project
LOCATION LATITUOE See Rooi Jida Geology Drawing CONTRACTOR Local labor
METHOD OF
EXCAVATION       Hand dug with shovel and pick WEATHER              Sunny and clear ELEVATIONS: DATUM MSL
GROUND SURFACE 2,562.28 ROCK SURFACE 2,560.93
JOB P6888 PIT RJD-5 SHEET 1 OF 2
(EELPA)
SITE Robi Jida - Right Bank DEPARTURE
STARTED 09:45               7/11/83
FINISHED 17:10 10/11/83 TEMPERATURE
BOTTOM OF PIT 2,559.2 8 WATER LEVEL 2.70 (10/11/83)
3.00 (29/11/83)
PIT LENGTH 2.0
WIDTH 2.0
DEPTH SAMPLE
3.0
DEPTH      SOIL TYPE          DESCRIPTION
0.00
Silty clay     Dark brown grading to dark gray below 0.3 m, silty clay with trace of subrounded gravel and cobbles of basaltic composition up to 15 cm m size, stiff,
greasy to gritty texture, hete- rogenous, moist, highly plastic. slight organic odor and organic
roots to 0.3 m
•TYPE         NO.         SIZE       DEPTH        qu_
Imml        (m)
GQ                1            Bulk       0.20
to
1.00
0.50                 1.75 1.00               1.40
GS                2            Bulk       0.30 to 1.05
1.35 Weathered Light gray, fine grained basalt,
basalt
3.00 
with phenocrysts of plagioclase, vesicular up to 2.0 m, moderately weak to moderately strong, highly weathered grading to moderately weathered toward bottom, highly permeable (possibly top of flow considerably weathered)
Bottom of test pit
Mote:        1 - The walls of the pit were stable and
‘
almost vertical.
2 - No sign of any collapse of the walls
observed during logging on November 29, 1983.
sampling method
SHIPPI
NG CONTAINER
•g _ tnm wall tuoe
0 - tUOe
s -
piartic oag
G - rnovei
P - tin
T-
me tai  n
a
n - carved diocm
Q - giais i«r
U-
woootn box
R - dotn oag
z -
qu unconfined compressive strength
• n xg/cm^ measured with pocket penetrometer
A
<J saroxj
imspfctoR Sevoum
Lemma
NT 0
n
approved
LOGGED p. Valliappan, Saia Monammed DATE De cemoer 1983
form 314 A : ,Test Pit Report
JOB P6888 PIT RJD-4 SHEET 1 OF 1
CLIENT          Ethiopian Electric Light and Power Authority PROJECT Aleltu Hydro Project
LOCATION LATITUDE            See Robi Jida Geoloov Drawing CONTRACTOR       Local labor
METHOD OF
EXCAVATION        Hand dug with shovel and pick WEATHER               Sunny and clear ELEVATIONS: DATUM         MSL
GROUND SURFACE 2,554.25 ROCK SURFACE 2,553.75
PIT LENGTH                2.0
WIDTH 2.0
'DEPTH        SOIL TYPE           DESCRIPTION
(EELPA)
SITE Robi Jida - Right Bank
DEPARTURE
STARTED 08:30               10/11/83
FINISHED 17:10               10/11/83 TEMPERATURE
BOTTOM OF PIT 2,553.25
WATER LEVEL Not encountered
DEPTH 1.0
SAMPLE
•TYPE        NO.        SIZE       DEPTH      qu — - —
(mm)       (m)
0.00
Silty clay
Dark gray silty clay with trace
GZ
1
Bulk
0.00
of subrounded gravel and cobbles
to
of basaltic composition up to
0.50
20 cm in size, medium stiff,
greasy to gritty texture, hete rogenous, moist, highly plastic, slight organic odor and organic roots to 0.3 m
0.50              Weathered              Light gray, fine grained
basalt
1.00
aphanitic with pnenocrysts of plagioclase and pyroxene, moder ately weak and moderately weathered at the top becoming strong and faintly weathered at the bottom of the pit, columnar jointed with size of blocks ranging from 10 to 25 cm Bottom of test pit
Note:         Unable to dig with hand tools below 1.0 m.
SAMPLING METHOD
*8 - thin wall (uM
G — move i
m - carved oiocm
SHIPPING CONTAINER
0 - tuoa
P - tin
Q — glass i«r
A - doth oag
S - pUstic sag
T - ma tai can
U - wooaan Dox
Z - d icaraea
qu unconfined compressive strength
•n <g/cm2 measured with pocKat penetrometer
INSPECTOR Sevoum Lemma --------------------------------------------- LOGGED p. Valliappan, Said Mohammed
APPROVED
DATE ___ norrhor 1QQ?
/
Form 314 A ilTest Pit Report
JOB P6888 PIT RJD-5 SHEET 1 OF 2
CLIENT Ethiopian Electric Light and Power Authority PROJECT Aleltu Hydro Project
LOCATION : LATITUDE See Robi Jida Geology Drawing CONTRACTOR Local labor
METHOD  OF
7/11/83
EXCAVATION
Hand dug with shovel and pick
WEATHER                Sunny ELEVATIONS:   DATUM
GROUND SURFACE ROCK SURFACE
and clear
MSL
2,562.28
2,560-93
(EELPA)
SITE Robi Jida - Right Bank DEPARTURE
STARTED 09:45 
FINISHED 17:10 10/11/83 TEMPERATURE BOTTOM OF PIT 2,559.28
WATER LEVEL 2.70 (10/11/83)
3.00 (29/11/83)
PIT LENGTH
2.0
WIDTH
2.0
DEPTH
3.0
DEPTH        SOIL TYPE            DESCRIPTION
SAMPLE
•TYPE NO. SIZE DEPTH qu_
Imml
(m)
0.00
Silty clay     Dark brown grading to dark gray below 0.3 m, silty clay with trace of subrounded gravel and cobbles of basaltic composition up to 15 cm in size, stiff,
greasy to gritty texture, hete- rogenous, moist, highly plastic.
GQ                 1             Bulk       0.20
to
1.00
0.5C                   1.75
1.00 GS                 2             Bulk       0.30
to 1.05
1.40
slight          organic          odor          and          organic roots to 0.3 m
1.35             Weathered               Light gray, fine grained basalt,
basalt
3.00 
with phenocrysts of plagioclase. vesicular up to 2.0 m, moderately weak to moderately strong, highly weathered grading to moderately weathered toward bottom, highly permeable (possibly top of flow consideranly weathered )
Bottom of test pit
Note:          1 - The walls of the pit were stable and
almost vertical.
2 - No sign of any collapse of the walls observed during logging on November 29,
sampling method
SHIPPING CONTAINER
•g — mm well tuoe
0 — tube
S - plastic o*q
G _ jnovei
P — tin
T - metal can
H — carved oiocx
1983.
qu unconfined comprewve Strength
• n <g/cm^ measured with oocnex penetrometer
Q — glass jar
U — wooden oom
R — doth oag
2     — U scaraea
INSPFCTOR Seyoum
Lemma
LOGGED p, Valliapcan Said Monammed
Form 31 J A 1 •■
Test Pit Report
JOB P6888
P’T RJD-5 SHEET 2 OF 2
DEPTH SOIL TYPE DESCRIPTION
SAMPLE
"TYPE
NO.        SIZE DEPTH (mm) (m)
qu
Note:          3 - Groundwater started seeping from 2.6 m.
4 - Pit wet and saturated at the bottom during logging on November 29, 1983.
Porm 314 A 2Test Pit Report
JOB P6888
PIT RJD-6 SHEET 1 OF 1
CLIENT         Ethiopian          Electric          Light          and          Power          Authority 
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Robi Jida Geology Drawing CONTRACTOR       Local labor
METHOD OF
EXCAVATION         Hand dug with shovel and pick
WEATHER              Sunny and clear
ELEVATIONS: DATUM MSL
(EELPA)
SITE Robi Jida - Right Bank DEPARTURE
STARTED 08:00 
FINISHED 16:10 TEMPERATURE BOTTOM OF PIT 2,580.91
9/11/93 10/11/83
GROUND SURFACE
ROCK SURFACE
PIT LENGTH 2.0
2,581.61
2,581.11
WATER LEVEL Not encountered
WIDTH 2.0
depth
0b7
DEPTH
0.00
SOIL TYPE         DESCRIPTION
Silty clay                 Dark brown grading to dark gray silty clay with trace of sub rounded gravel and cobbles up to 20 cm in size, greasy to gritty texture, highly plastic, slight organic odor and organic roots to 0.2 m
SAMPLE
•TYPE NO.
GZ                 1
SIZE       DEPTH       qu_ (mmi        (m)
Bulk         0.00 to 0.50
0.50
Weathered basalt
0.70
Light gray, fine grained basalt, vesicular, vesicles partially 
filled with yellowish weathered material, moderately strong to very strong, moderately weathered to faintly weathered with depth, columnar jointed with block sizes ranging from 20 to 40 cm
Bottom of test pit
Note: Unable to dig with hand tools below 0.70 m
SAMPLINC METHOD
SHIPPING CONTAINER
*8 — tnm wvall tuoa
0-
tuoa                    S — plastic baq
G - shovei
p-
tin                          T - matai an
m - carvea oioc*
qu uncontinea comprassiva strengtn
• n cm* rraasuraa with pockat panwtromarar
Q-
giau jar
U - wooam ook
R-
doth Dag             Z — u sardea
INSPECTOR Sevoum
Lemma
LOGGED P. Valliappan, Said Mohammed
APOROVED DATE
c prm 314 A 1'Test Pit Report
JOB P6888 PIT TP-100 SHEET 1 OF 1
CLIENT            Ethiopian Electric Light and Power Authority
PROJECT LOCATION
Aleltu Hydro Project
LATITUDE See Impervious Borrow Area Drawing
(EELPA) SITE Jima DEPARTURE
Impervious Borrow
Are.
CONTRACTOR       Local labor METHOD OF
EXCAVATION
Hand     dug     with     shovel     and     pick     and     hand 
STARTED
FINISHED
09:20
16:30
18/11/83
19/11/83
WEATHER
auger
Sunny
ELEVATIONS:  DATUM GROUND SURFACE ROCK SURFACE
and clear
MSL
2,603.72
Not encountered
TEMPERATURE BOTTOM OF PIT 2,599.12 WATER LEVEL       2.4
PIT LENGTH
2.0
WIDTH
2.0
OEPTH 2.5 2.5
SAMPLE
(test Pit) to 4.6 (auger hole)
DEPTH       SOIL TYPE           DESCRIPTION
•TYPE        NO.        SIZE (mm)
DEPTH       qu_
0.00
Silty clay      Dark brown grading to dark gray oelow 0.3 m, stiff, greasy to floury texture, homogenous. moist, highly plastic, slight organic odor and organic roots to 0.4 m, trace of white
partially weathered fragments of basalt up to 3 cm in size
1.4C             Silty clay                Light gray silty clay to clayey
with
silt with some partially
weathered               weathered white suorounded
fragments of basalt
basaltic fragments up to 4 cm in size, stiff, greasy to granular texture, homogenous, moist becoming wet with depth,
GQ               1            3ulk      0.20
to
1.00
0.50              1.75 GS               2           Bulk      0.20
to
1.00
1.00             1.35
GR               3           Bulk       1.40
to
4.60
1.50              1.50
medium
plastic
4.60
Bot tom
of test pit
Note:          1
-    Pit extended by
augering below 2.5
2   -    Observed tension cracks and caving
m.
of
walls      up      to      1.4      m      during      logging  on November 25, 1983.
sampling methoo
’S - thin wall tuoe
G - shovel
m - carved bloc*
INSPECTOR Seyoum Lemma
shipping container
0 - tube
P - tin
Q - glass iar
A - doth bag
s    -   panic bag
qu  unconTineo
compressive strengtn
T-
U-
2-
mcui can
wooden pox
J saroed
•n xg/cm2
measured with pocxet penetrometer
LOGGED
P. Valliappan, Said Mohammed
approved OATE Decembe
Form 314 A , 1 .Test Pit Report
CLIENT          Ethiopian           Electric           Light           and           Power           Authority 
PROJECT Aleltu Hydro Project
LOCATION : LATITUDE See Impervious Borrow Area Drawing CONTRACTOR      Local labor
METHOD OF
JOB P6888
PIT TP-101 SHEET 1 OF 1
(EELPA)
SITE Jima Impervious Borrow Aree DEPARTURE
EXCAVATION
WEATHER
Hand dug with shovel and pick and hand auger
Sunny and clear
STARTED 09:25
FINISHED 16:30 TEMPERATURE
18/11/83
19/11/83
ELEVATIONS: DATUM       MSL GROUND SURFACE        2,604.91 ROCK SURFACE        Not encountered
PIT LENGTH
DEPTH
2.0
SOIL TYPE
WIDTH              2.0 
BOTTOM OF PIT            2,602.41 WATER LEVEL 2.30
DEPTH 2.0 (test pit)
2.0 to 2.5 (auger hole)
SAMPLE
DESCRIPTION
•TYPE         NO.         SIZE       DEPTH
qu_
0.00                    Silty clay           Dark brown grading to dark gray below 0.3 m, very stiff becoming
stiff with depth, greasy to
floury texture, homogenous.
moist, highly plastic, slight organic odor and organic roots
up to 0.4 m, trace of white
partially weathered fragments of basalt to 2 cm in size
(mm)      (m)
GQ                 1             Bulk       0.20
to
1.00
0.50                3.8 1.00               2.5
GO                 2             Bulk        1.00 to 2.00
GR                 3             Bulk
1.50 0.40 to
1.60
2.1
1.60            Silty clay                 Light gray silty clay to clayey
with
silt with some partially
weathered            weathered white sub rounded
fragments
basaltic fragments up to 4 cm
GR                 4           Bulk        1.60
to
2.50
2.00                1.9
2.50
Note: 1
of basalt              in size, stiff, greasy to granular texture, homogenous, moist becoming wet with depth, medium plastic
Bottom of test pit
-    Pit extended by
augering De low 2.0 m.
2   -    Observed tension cracks on the walls of the test
pit
up
to
sampling
method
1.6 m during logging on November 25, 1983.
SHIPPING CONTAINER
O - tuoe
P — tin
Q — glass jar
R - doth bag
s
T
U
z
strength
inspector LOGGED
Sevoum Lemma
P. Vailiappan, Said Mohammed
APPROVED
DATE December 198 3Test Pit Report
JOB
PIT
P6888
TP-100
SHEET 1 OF 1
CLIENT PROJECT LOCATION
Ethiopian Electric Light and Power Authority Aleltu Hydro Project
LATITUDE See Impervious Borrow Area Drawing
(EELPA) SITE Jima DEPARTURE
Impervious Borrow Ared
CONTRACTOR       Local labor METHOO OF
EXCAVATION
Hand     dug     with     shovel     and     pick     and     hand 
STARTED
FINISHED
09:20
16:30
18/11/83
19/11/83
WEATHER
auger
Sunny
ELEVATIONS:  DATUM GROUND SURFACE ROCK SURFACE
and clear
MSL
2,603.72
Not encountered
PIT LENGTH
2.0
WIDTH
2.0
TEMPERATURE BOTTOM OF PIT 2,599.12 WATER LEVEL       2.4
DEPTH 2.5 (test pit)
2.5 to 4.6 (auger hole)
SAMPLE
DEPTH       SOIL TYPE           DESCRIPTION
•TYPE        NO.        SIZE      DEPTH
21
Immi
-(»>
0.00
Silty clay     Dark brown grading to dark gray below 0.3 m, stiff/ greasy to floury texture, homogenous. moist, highly plastic, slight organic odor and organic roots to 0.4 m, trace of white
partially weathered fragments of basalt up to 3 cm in size
1.40             Silty clay                Light gray silty clay to clayey
with
silt with some partially
weathered               weathered white subrounded
fragments of basalt
basaltic fragments up to 4 cm in size, stiff, greasy to granular texture, homogenous, moist becoming wet with depth, medium plastic
GQ              1            Bulk     0.20
to
1.00
0.50               1.75 GS              2            Bulk     0.20
to
1.00
1.00               1.35
GR              3            Bulk      1.40
to
4.60
1.50               1.50
4.60
Note:
1  - Pit extended by
of test pit
Bottom
augering below 2.5
2   - Observed tension cracks and caving
m.
of
walls      up      to      1.4      m      during      logging  on November 25, 1983.
sampling methoo
*8 - thin wall tupe
G - snovei
M — carvaa oiock
INSPECTOR Seyoum Lemma
shipping container
0     - tube
P — tin
Q - gms i«r
R - doth peg
S-
T-
U-
z -
Qu unconfmea comprewve strength
measure a with pocnet penetrometer
LOGGED
P. Vaillappan, Said Mohammed
APPROVED
DATE Decembe j\-il983
Form 314 A 1 |Test Pit Report
CLIENT
PROJECT
LOCATION
Ethiopian Electric Light and Power Authority Aleltu Hydro Project
LATITUDE See Impervious Borrow Area Drawing
JOB       p6888
PIT       TP-101 SHEET 1 OF 1
(EELPA)
SITE Jima Impervious Borrow Area
departure
CONTRACTOR
METHOD OF
EXCAVATION
WEATHER
Local labor
Hand  dug  with  shovel and  pick  and  hand 
STARTED 09:25
18/11/83
aucer
Sunny
ELEVATIONS: DATUM
GROUND SURFACE
and clear MSL 2,604.91
FINISHED 16:30 19/11/83
TEMPERATURE
BOTTOM OF PIT 2,602.41
WATER LEVEL         2.  30
ROCK SURFACE
PIT LENGTH 2.0
Not
encountered
WIDTH
2.0                          DEPTH
2.0
2.0
(test pit)
to 2.5 (auger hole)
SAMPLE
DEPTH
SOIL TYPE
DESCRIPTION
•TYPE
NO.
SIZE
(mm)
DEPTH
(mJ
qu
0.00
Silty clay
Dark brown grading to dark gray
GC
1
Bulk
0.20
below 0.3 m, very stiff becoming stiff with depth, greasy to floury texture, homogenous. moist, highly plastic, slight organic odor and organic roots up to 0.4 m, trace of white partially weathered fragments
of basalt to 2 cm in size
to
1.00
0.50                  3.8 1.00                  2.5
GO                2             Bulk        1.00 to 2.00
1.50 0.40 to
1.60
2.1
GR                 3             Bulk
1.60              Silty clay                 Light gray silty clay to clayey
GR                 4             Bulk        1.60
with
silt with some partially
to
weathered
weathered white subrounded
2.50
fragments
basaltic fragments up to 4 cm
2.00
1.9
of Dasalt
in size, stiff, greasy to 
granular texture, homogenous,
moist becoming wet with depth,
medium
plastic
2.50
Note: 1
Bottom       of test pit
-    Pit extended by
auger mg oelow 2.0 m.
2   -   Observed tension cracks on the walls of the test
pit
up
to
1.6 m during logging on November 25, 1983.
SAMPLING    method
SHIPPING CONTAINER
•B — thin wail tube G - snovei
O - tub«
P - tin
strength
H — carved bloc*
qu unconf inea
m kg/cm
Q — giau )«r
R - cloth OAq
S
T
U
z
INSPECTOR
Sev
oum
Lerma
APPROVED
LOGGED
P.
Vallx
appan, Said Mo
nammed
DATE
Form 31 4 A 111Test Pit Report
JOB P6888
PIT TP-102 SHEET 1 OF 1
CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUOE See Impervious Borrow Area Drawing DEPARTURE
SITE Jima Impervious Borrow Area
CONTRACTOR
METHOD OF
EXCAVATION
WEATHER
ELEVATIONS.
Local labor
Hand dug with shovel and pick
Sunny
DATUM
and clear MSL
2/606.49
18/11/83 19/11/83
2/604.49
GROUND SURFACE
STARTED 09:35
FINISHED 14:00 TEMPERATURE BOTTOM OF PIT WATER LEVEL 1.30
ROCK SURFACE
TRENCH LENGTH
Not
2.0
encountered
See Notes 1
WIDTH         2.0
DEPTH
2.0
SAMPLE
DEPTH
0.00
SOIL TYPE          DESCRIPTION
Silty clay                  Dark brown grading to dark gray below 0.3 m, stiff becoming medium stiff with depth, greasy to floury texture, homogenous, moist, highly plastic, slight organic odor and organic roots to 0.4 m
•TYPE
NO.
SIZE
(mm)
DEPTH im^
GQ
1
Bulk
0.20
to
1.00
0.50
GR
2
Bulk
0.20
to
1.00
1.00
1.10
Silty clay
to clayey
GS
3
Bulk
1.10
to
silt
Light gray silty clay to clayey silt, stiff, greasy to floury texture, homogenous, moist becoming wet with depth, highly plastic, occasional fragments
of partially weathered basalt toward bottom
Bottom of test pit
1.30
GQ
4
Bulk
1.10
to
1.30
1.50
2.00
Note: 1 2 3
Unable to excavate below 2.0 m because
of seepage and accumulation of ground water.
Observed          tension          cracks          on the      test      pit     up     to      1.0      m
on Novemoer 25
/ 1983.
Water
collected in rhe pit
tne walls of during logging is very clear.
sampling method
SHIP°ING CONTAINER
*9 — thin wall tuee G - shovel
O — tuoe
P - tin
m - orvec block
S
T
U
DUPiC osg matai an
qu
Q — giau tar
wooaen box
unconfjnaa comoresjjvs sxrengtn
^•surea with pocket penetrometer
R - cloth naq
z
duardea
INSPECTOR LOGGED
Seyoum Lemma
APPROVED
P. Valliappan, Said Monammed DATE DecemberTest Pit Report
JOB P6888 PIT TP-103 SHEET 1 OF 1
CLIENT PROJECT
Ethiopian Electric Light and Power Autnority (EELPA) Aleltu Hydro Project
SITE Jima Impervious Borr
Area
LOCATION LATITUDE See Impervious Borrow Area Drawing     DEPARTURE
CONTRACTOR                 Local labor
METHOO OF
EXCAVATION Hand dug with shovel
and pick
WEATHER
Sunny and clear
ELEVATIONS: OATUM   MSL GROUND SURFACE     2,608.74 ROCK SURFACE           2,607.64
TRENCH LENGTH            2.0 
WIDTH           2.0
STARTED 14:15              19/11/83
FINISHED 12:00             22/11/83 TEMPERATURE
BOTTOM OF PIT           2,606.74 WATER LEVEL              1.80
DEPTH          2.0 SAMPLE
DEPTH       SOIL TYPE         DESCRIPTION
0.00 Silty Dark brown grading to dark gray
clay
below 0.3 m, very stiff becoming stiff witn depth, greasy to
floury texture, homogenous, moist, highly plastic, slight organic
odor and organic roots to 0.4 m
•TYPE        NO.         SIZE       DEPTH       qu
(mm)      Im}
GQ             1            Bulk       0.20
to
1.00
0.50                3.5 1.00                1.3
GS             2            Bulk       0.30 to
1.10
1.10
Weathered
Light gray highly to completely
GZ
3
Bulk
1.10
basalt
weathered basalt with subangular
to
to subrounded fragments up to
1.80
15     cm     in     size,     weak     to     very 
weak,
moderate to highly permeable
2.00 
3ottom of test pit
Note: Unable to dig with hand tools below 2.0 m.
SAMPLING METHOO
SHIPPING CONTAINER
*3 — rmn wall tuoa
G - $novei
h - carv«a oiock
0 - tuba
P - tin
Q - glass jar
S - plastic oag
T - matai can
U - woooan oox
Pu unconfmaa compressivf strangth
• n <g,cm2 maasurwo with pocxat panetromatar
R - aotn oag               Z - aiscaraed
A
.MCPFCTOR SeyOurn                       Lemma
OGGED p- ValliaPPan* Said Mohammed
A
APPROVED
DATE Dec emo er
Form 314 A llTest Pit Report
JOB P6888
PIT TP-102
SHEET 1 OF 1
CLIENT Ethiopian Electric Light and Power Authority (EELPA)
PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Impervious Borrow Area Drawing DEPARTURE CONTRACTOR        Local labor
METHOO  OF
EXCAVATION
WEATHER
ELEVATIONS.
Hand dug with shovel and pick
Sunny
DATUM
GROUND SURFACE
and clear MSL 2,606.49
ROCK SURFACE
TRENCH LENGTH
Not
2.0
encountered
WIDTH
2.0
DEPTH       SOIL TYPE          DESCRIPTION
0.00
Silty clay      Dark brown grading to dark gray oelow 0.3 m, stiff becoming medium stiff with depth, greasy to floury texture, homogenous, moist, nignly plastic, slight organic odor and organic roots to 0.4 m
SITE Jima Impervious Borrow Area
STARTED 09:35               18/11/83
FINISHED 14:00               19/11/83
TEMPERATURE
BOTTOM OF PIT 2,604.49
WATER LEVEL 1.30
See Notes 1 and 3 DEPTH 2.0
SAMPLE
•TYPE          NO.         SIZE       DEPTH       qu
——
imml       (m/ GQ                1            Bulk       0.20
1.10              Silty clay                  Light gray silty clay to clayey
to clayey
silt
2.00
silt, stiff, greasy to floury texture, homogenous, moist becoming wet with depth, highly plastic, occasional fragments
of partially weathered basalt toward bottom
Bottom of test pit
to
1.00
0.50                  1.10
GR                2             Bulk       0.20
to
1.00
1.00                  0.75 GS                 3            Bulk       1.10
to
1.30
GQ                4            Bulk       1.10
to
1.30
1.50                1.55
Note:          1 - Unable to excavate below 2.0 m because
of        seepage        and        accumulation        of        ground water.
2   - Observed tension cracks on the walls of
the      test      pit      up      to      1.0      m      during      logging on November 25, 1983.
3   - Water collected in the pit is very clear.
sampling method ‘3 — thin wail xuD«
SHIP°ING CONTAINER
□     — ruoa
G - shovwi
h - carved dock
P — tin
S — planic oag
T — rneial can
□     - 3  lais jar A — doth oaq
U — wooden Dox Z — discarded
qu unconfinto comp revive jtrangtn
•n <g,cm2 maasurao with pocxet penetrometer
INSPECTOR
Sevoum
lemma
APPROVED
LOGGED
P. Valliapp
an, Said Mohamm
ed
1 E De cember 19 3Test Pit Report
Bii
JOB pease PIT TP-103 SHEET 1 OF 1
CLIENT
PROJECT
Ethiopian Electric Light and Power Authority (EELPA) Aleltu Hydro Project
LOCATION LATITUDE See Impervious Borrow Area Drawing DEPARTURE CONTRACTOR                 Local labor
METHOD OF
EXCAVATION Hand dug with shovel
and pick
WEATHER
Sunny and clear
ELEVATIONS: DATUM   MSL GROUND SURFACE     2,608.74 ROCK SURFACE           2,607.64
TRENCH LENGTH            2.0 
SITE J^a Impervious Borrow Area STARTED 14:15 19/11/93
FINISHED 12:00             22/11/83 TEMPERATURE
BOTTOM OF PIT           2,606.74 WATER LEVEL             1.80
WIDTH           2.0
DEPTH       SOIL TYPE         DESCRIPTION
0.00 Silty Dark brown grading to dark gray
DEPTH          2.0
SAMPLE
•TYPE        NO.         SIZE (mm)
OEPTH (mJ
qu_
GQ             1            Bulk       0.20
clay
below 0.3 m, very stiff becoming stiff with depth, greasy to
floury texture, homogenous, moist, highly plastic, slight organic
odor and organic roots to 0.4 m
1.10            Weathered             Light gray highly to completely
to
1.00
0.50                3.5 1.00                1.3
GS             2            Bulk       0.30 to 1.10
GZ             3            Bulk       1.10
basalt
weathered basalt with subangular
to
to subrounded fragments up to
1.80
15     cm     m     size,     weak 
to     very     weak,
moderate to highly permeable
2.00 
Bottom of test pit
Note: Unable to dig with hand tools below 2.0 m.
SAMPLING METHOO
•g — tmn wall tuo*
G - snovei
M — carved oiocx
SHIPPING CONTAINER
0 - tuoe
P - tin
s-
T-
Q - glass iar
U-
R - aotn bag
z -
plastic bag
metai can
woooen dox
disoraed
Qu unconfmec compressive strengtn
•n <g.cm^ measured with pocxet penetrometer
mcppctor Seyoum            Lemma
APPROVED
logged
p. Valliappar., Said Mohammed
xjTest Pit Report
JOB PIT SHEET
P6338 TP-104
1 OF 1
CLIENT Ethiopian Electric Light
PROJECT Aleltu Hydro Project
and Power Authority
(EELPA)
SITE
Impervious Borrow Ared
LOCATION . LATITUDE See Impervious
Borrow Area Drawing
DEPARTURE
CONTRACTOR
Local labor
STARTED       13:00 
23/11/83
METHOD OF
EXCAVATION       Hand dug with shovel
and pick and hand
FINISHED       14:30
24/11/83
WEATHER
auger
Sunny and clear
TEMPERATURE
ELEVATIONS: DATUM
MSL
BOTTOM OF PIT
2,602.54
GROUND SURFACE         2,604.34
WATER LEVEL
Not encountered
ROCK SURFACE       Not
encountered
PIT LENGTH
2.0
WIDTH 2.0
DEPTH 1.5 (test
pit)
DEPTH       SOIL TYPE           DESCRIPTION
0.00              Silty clay                Dark brown grading to dark gray
below 0.3 m, very stiff, greasy
to floury texture, homogenous.
mcist, highly plastic, slight
organic odor and organic roots
to 0.4 m, trace of white
partially           weathered           coarse           sand size fragments of basalt
1.10             Silty clay                Light gray silty clay to clayey
1.5 to 2.3 (auger hole) SAMPLE
•TYPE        NO.        SIZE (mm)
DEPTH      51
with
of basalt
weathered
weathered white subrounded
to
fragments
basaltic fragments up to 2 cm
silt with some partially
in size, very stiff, greasy to granular texture, homogenous, moist becoming wet with depth,
GQ               1           Bulk      0.20
to
1.10
0.50                2.50 GS               2           Bulk      0.20
to
1.10
1.20                2.25
GS                3           Bulk       1.10
2.30
medium
2.30
Note:
Bottom
1 - Pit extended by
plastic
of test pit
augering below 1.5 m.
2 - Observed tension cracks on the walls
of the test pit up to 1.0 m during
logging      on November      28, 1983.
SAMPLING METHOD
SHIPPING CONTAINER
*8 - thin wall tube
G - shovel
0 - tuba
P — tin
S - plastic bag
T — matai an
Qu unconfmed
• n kg/cm2
strength
H - carved oiock
Q - glass jar R - doth beg
U - wooden box Z - d-scanted
INSPECTOR
Seyoum
Lemma
LOGGED
?. Valliapp
an, Said
Monammed
APPROVED
DATE
Form 314 A»1)Drilling Report
JOB P6888
HOLE AH-105
SHEET 1 OF 1
CLIENT
PROJECT
SITE
Ethiopian Electric Light and Power Authority Aleltu Hydro Project
Jima Impervious Borrow Area
(EELPA)
CONTRACTOR       Local labor
09:30  23/11/83
15:00  23/11/83
METHOD OF
DRILLING:
LOCATION:
SOILAugermg  with  post hole
ROCK Not encountered
STARTED
FINISHED
auger CASING Di AM
CORE DIAM
LATITUDE
)
)
See Imoervious
ELEVATIONS: DATUM
DRILL PLATFORM
MSL
DEPARTURE
Borrow Area Drawing
8EARING
INITIAL DIP
90 deg
OTHER  DIPS
GROUND SURFACE 2,605.40 ROCK SURFACE Not encountered BOTTOM OF HOLE 2,603.00 WATER LEVEL Not encountered
PENE-
SAMPLE
___________________ TRATION
OEPTH
0.00
SOIL TYPE
DESCRIPTION
•TYPE I
NO.
SIZE DEPTH RET'D TEST
1.10
Silty clay
Silty clay to clayey silt
Dark gray silty clay, greasy to floury texture, moist, medium plastic
Light gray silty clay to clayey silt with some partially wea thered coarse sand size fragments of basalt, greasy to floury texture, moist, highly plastic Bottom of auger hole
GZ
1
Bulk 0.30 
to
1.00
GS
2
Bulk 1.10 
to
2.40
2.40
SAMPLING METHOD
•A - split tape
3 _ thin wall tuoe
C - piston sampler
D - care oarrti
SHIPPING    container
E - auger
F — wesn
n
□    tuoe
insert
INSPECTOR Seyoum Lemma
LOGGED BY p, Valliappar., Said Mohammed
Form 3’9 A 1PROJECT Aleltu Hydro Project
SITE Jima
Impervious Borrow Arec
LOCATION LATITUDE See Impervious
Borrow Area Drawing
DEPARTURE
CONTRACTOR
Local labor
STARTED
13:00 
23/11/83
METHOD OF
EXCAVATION       Hand dug with shovel
and pick and hand
FINISHED       14:30
24/11/83
WEATHER
auqer
Sunny
and clear
TEMPERATURE
ELEVATIONS: DATUM       MSL
BOTTOM OF PIT
2,602.54
GROUND SURFACE         2,604.94
WATER LEVEL
Not encountered
ROCK SURFACE       Not
encountered
PIT LENGTH
2.0
WIDTH
2.0
DEPTH 1.5 (test
pit)
DEPTH       SOIL TYPE          DESCRIPTION
0.00             Silty clay               Dark brown grading to dark gray
below 0.3 m, very stiff, greasy
to floury texture, homogenous.
moist, highly plastic, slight
organic odor and organic roots
to 0.4 m, trace of white
partially           weathered           coarse           sand size fragments of basalt
1.10             Silty clay                Light gray silty clay to clayey
1.5 to 2.3 (auger hole) SAMPLE
•TYPE        NO.        SIZE (mm)
DEPTH      21
(m->
with
of basalt
GQ               1           Bulk      0.20
to
1.10
0.50               2.50 GS               2           Bulk      0.20
to
1.10
1.20             2.25
GS                3            Bulk       1.10
weathered
weathered white subrounded
to
fragments
basaltic fragments up to 2 cm
silt with some partially
in size, very stiff, greasy to granular texture, homogenous,
moist becoming wet with depth,
2.30
medium
plastic
2.30
Bottom
Note:         1 - Pit extended by                      augering below 1.5 m.
2 - Observed tension cracks on the walls
of the test pit up to 1.0 m during 
logging        on November 28, 1983.
SAMPLING METHOD
SHIPPING CONTAINER
— thin wall tube
O - tuo«
S-
G - snovei
P — tin
T-
qu uncont.nea cocmopmrapuf»ivwa»si tSretrnegntghth
H - carved Block
Q - gias jar
U-
2
•n kg/cm maawrao with pocket penetrometer
R - doth bag
z -
INSPECTOR Seyoum
Lemma
APPROVED
LOGGED
Valliapoan, Said Mohamme
d
DATE
Form 314 A illDrilling Report
H
JOB P6888
HOLE AH-105
SHEET 1 OF 1
CLIENT          Ethiopian Electric Light and Power Authority
PROJECT Aleltu Hydro Project
SITE               Jima Impervious Borrow Area CONTRACTOR Local labor
(EELPA)
METHOO OF
DRILLING
SOILAugering with post hole ROCK Not encountered
LOCATION:        LATITUDE
DEPARTURE
BEARING
INITIAL DIP OTHER DIPS
) See ImDervious
) Borrow Area Drawing 90 deg
STARTED        09:30 23/11/83
FINISHED        15:00 23/11/83
auger CASING Di AM
CORE OIAM
ELEVATIONS: OATUM
DRILL PLATFORM
MSL
GROUND SURFACE 2,605.40 ROCK SURFACE Not encountered BOTTOM OF HOLE 2,603.00 WATER LEVEL Not encountered
DEPTH      SOIL TYPE     DESCRIPTION
0.00              Silty clay
1.10              Silty clay to clayey silt
2.40
Dark gray silty clay, greasy to floury texture, moist, medium plastic
Light gray silty clay to clayey silt with some partially wea thered coarse sand size fragments of basalt, greasy to floury texture, moist, highly plastic Bottom of auger hole
SAMPLE
•TYPE I  NO. GZ            1
GS            2
PENE- ___________________ TRATION SIZE OEPTH RET'O TEST
Bulk 0.30 
to
1.00 Bulk 1.10 
to
2.40
SAMPLING METHOO
•A — spin tube
3 — tnin            tuoe
C - pisxon ampler
□ - core oarrei
E - auger
F — wash
SHIPPING CONTAINER
N — mien
0 - tune
P — A/ater content tin
R — ciotn oaq
S — piartic nag
Y — core box
INSPECTOR Seyoum Lemma
LOGGED BY p Valliappar., Said Mohammed
Q — glass ,ar
APPROVED
DATE     Decembe
Form 318 A 1 >X Qo5
■
Test Pit Report
CLIENT Ethiopian Electric Light and Power Authority PROJECT Aleltu Hydro Project
LOCATION LATITUDE See Impervious Borrow Area Drawina
JOB P6888
PIT TP-107 SHEET 1 OF 1
(EELPA)
SITE Jima Impervious Borrow Area DEPARTURE
CONTRACTOR
METHOO OF
EXCAVATION
WEATHER
Local labor
Hand dug witn shovel and pick Sunny and clear
ELEVATIONS. DATUM       MSL GROUND SURFACE      2,604.02 ROCK SURFACE           2,602.37
PIT LENGTH             2.0
STARTED 08:20
FINISHED 10:00 TEMPERATURE BOTTOM OF PIT WATER LEVEL
21/11/83
23/11/83
2,601.72
Not encountered
WIDTH 2.0
DEPTH 2.3
SAMPLE
DEPTH      SOIL TYPE          DESCRIPTION
0.00
Silty clay     Dark brown grading to dary gray below 0.3 m, very stiff becoming stiff with depth, greasy to floury texture, homogenous. moist, highly plastic, slight organic odor and organic roots to 0.4 m
•TYPE        NO.         SIZE DEPTH (mm)      (m)
GQ               1           Bulk 0.20
to
1.00 0.50 1.00
GS               2                Bulk 0.40 to
1.60
GQ               3
1.65 Weathered Light gray to pinkish, highly to GZ
4 Bulk 1.70 
basalt
completely weathered oasalt with subangular to subrounded fragments up to 15 cm in size, weak to very weak
Bottom of test pit
Bulk 1.00
to
1.75 1.65
to
2.30
2.30
Note: 1 - Unable to dig with hand tools below 2.3 m.
2 - Observed tension cracks and caving of walls up to 1.5 m during logging on November 25, 1983.
sampling method
— thin wall tube
— shovel
— carved block
SHIPPING CONTAINER
O — tube
P — tin
Q - gun jer
R - aotn bag
S — plastic bag
T — metal can
U — wooden box
Z — d.sarded
qu unconfineo oompreuive strengtn
•n kg/cm^ measured with pocxet penetrometer
INSPECTOR      Sevoum Lemma________________________ LOGGED p, Valliappan. Said Mohammad
Form 314 Ail)Drilling Report
JOB P6888 HOLE AH-108 SHEET 1 OF 1
CLIENT
Ethiopian Electric Light and Power Authority
(EELPA)
PROJECT     Aleltu Hydro Project
Jima Impervious Borrow Area
CONTRACTOR Local labor
METHOD OF
DRILLING:
LOCATION:
SOlLAugering with post hole
ROCK Not encountered
STARTED FINISHED
auger CASING DIAM CORE DIAM
08:30  21/11/83
13:00  21/11/83
LATITUDE ) DEPARTURE ) BEARING INITIAL DIP OTHER DIPS
See Impervious Borrow Area Drawing
ELEVATIONS: DATUM
DRILL PLATFORM
MSL
90 deg
GROUND SURFACE 2,604.08 ROCK SURFACE Not encountered BOTTOM OF HOLE 2,601.18 WATER LEVEL 2.3 m
DEPTH 0.00
SOIL TYPE    DESCRIPTION
SAMPLE
•TYPE I NO. SIZE OEPTH RET’D
PENE TRATION TEST
Silty clay
Dark gray silty clay, greasy to floury texture, moist, highly 
plastic, trace of white partially weathered fragments of oasalt up to 2 cm in size
GS           1
Bulk 0.20 
to1. 00
Silty clay 
with weathered fragments of basalt
Light gray silty clay to clayey silt with some partially wea thered white fragments of basalt up to 2 cm in size, moist becom ing wet with depth, medium plastic
Bottom of auger hole
GZ          2
Bulk 2.15 
to
2.90
SAMPLING  method
A — spilt tUD4
g - tnm well tube
C - piston semoier
□ - core o«rre»
INSPECTOR Seyoum Lemma
SHIPPING CONTAINER
E - auger
r - .vein
gias jir
APPROVED
ciotn oaq
P’emc bag
=or» oox
aisoraea
iI
Mil/
LOGGED BY p. Valliappan, Said Mohammed
OATE
Decembe^ 1983
Form 318 A 1|Test Pit Report
CLIENT Ethiopian Electric Light PROJECT Aleltu Hydro Project LOCATION LATITUDE See Impervious CONTRACTOR        Local labor
METHOD OF
and Power Authority Borrow Area Drawincr
JOB P6888 
PIT TP-10 7 SHEET 1 OF 1
(EELPA)
SITE Jima Impervious Borrow Area DEPARTURE
STARTED 08:20            21/11/83
EXCAVATION
WEATHER
Hand dug with shovel and pick Sunny and clear
ELEVATIONS: DATUM       MSL
GROUND SURFACE
ROCK SURFACE
PIT LENGTH 2.0
2,604.02
2,602.37
FINISHED      10:00 TEMPERATURE BOTTOM OF PIT WATER LEVEL
23/11/83
2,601.72
Not encountered
WIDTH 2.0
DEPTH      SOIL TYPE          DESCRIPTION
DEPTH 2.3
SAMPLE
•TYPE         NO.        SIZE DEPTH
(mm)       (m)
GQ               1          Bulk 0.20
qu_
0.00
Silty clay     Dark brown grading to dary gray
below 0.3 m, very stiff becoming
to
stiff with depth, greasy to
1.00
floury texture, homogenous.
0.50
2.50
moist, highly plastic, slight
1.00
1.50
organic odor and organic roots
GS
2
Bulk 0.40
to 0.4 m
to
1.60
GQ
3
Bulk 1.00
to
1.75
1.65
1.25
1.65             Weathered
Light gray to pinkish, highly to
GZ
4
Bulk 1.70
basalt
completely weathered basalt with subangular to subrounded fragments up to 15 cm in size,
weak to very weak
Bottom of test pit
dig with hand tools below 2.3 m.
to
2.30
2.30
Note: 1 - Unable to
2 - Observed tension cracks and caving of walls up to 1.5 m during logging on November 25, 1983.
SAMPLING METHOD
•S - chin wall tuba
G - shovat
SNIPPING CONTAINER
O - tuba
p - tin
S - plttic bag
T - ma tai can
qu unconfinea compr«sav« strength
m Kg/cm^ measure a with pocket penetrometer
N - carvers bloc*
Q - gun iar
U-
bow
R - doth bag
z “ dscaroao
INSPECTOR
Sevoum
Lemma
LOGGED r, ValliaPC-an. Said Mohammed
Form 314 ADrilling Report
JOB P6888 HOLE AH-108 SHEET 1 OF 1
CLIENT
Ethiopian Electric Light and Power Authority
(EELPA)
PROJECT     Aleltu Hydro Project
Jima Impervious Borrow Area CONTRACTOR Local labor
METHOD OF
DRILLING:
LOCATION:
SOlLAugering with post hole
STARTED FINISHED
auger CASING DIAM CORE DIAM
08:30  21/11/83
13:00  21/11/83
ROCK Not encountered
LATITUDE )
See Impervious
ELEVATIONS; DATUM
MSL
DEPARTURE )
Borrow Area Drawina
DRILL PLATFORM
SEARING
GROUND SURFACE 2,604.08 
INITIAL DIP
90 deg
ROCK SURFACE Not encountered 
OTHER OIPS
BOTTOM OF HOLE 2,601.18 
WATER LEVEL 2.3 m
SAMPLE
PENE TRATION
DEPTH      SOIL TYPE    DESCRIPTION
•TYPE
NO. SIZE DEPTH RET'D
TEST
0.00            Silty                Dark gray silty clay, greasy to clay                 floury texture, moist, highly 
GS
1     Bulk 0.20 
plastic, trace of white partially 
to
1.00
weathered fragments of basalt up 
Silty 
clay 
with weathered fragments of basalt
to 2 cm in size
Light gray silty clay to clayey silt with some partially wea thered white fragments of basalt up to 2 cm in size, moist becom ing wet with depth, medium plastic
Bottom of auger hole
GZ          2
Bulk 2.15 
to
2.90
2.90
sampling method
•A — sp>'( ruoe
g _ mm wall (udi
C - piston sampler
□ - core Dirrei
INSPECTOR Sevoum Lemma
SHIPPING CONTAINER
E - auger
F - .vain
v - nsarr
R-
0 - tuoe
S-
P - water content tin
Y-
Q — gias jar
Cloth 3aq
pianic oag
core pom
auaraec
APPROVED
LOGGED BY p, Valliappan, Said Mohammed
OATE         De
cembe^ 1983
Form 318A 1 ’Drilling Report
JOB P6888 HOLE AH-109 SHEET 1 OF
CLIENT PROJECT
Ethiopian Electric Light and Power Authority
(EELPA)
Aleltu Hydro Pro}ect
SITE
Jima Impervious Borrow Area
CONTRACTOR
Local labor
STARTED
13:00 
21/11/83
FINISHED
17:00 
21/11/83
METHOD OF DRILLING.
LOCATION:
SOIL Augenng with post hole auger CASING DI AM
ROCK Not
encountered
LATITUDE DEPARTURE BEARING INITIAL DIP OTHER  DIPS
)
)
See Impervious Borrow Area Drawing
CORE DiAM
ELEVATIONS: DATUM
DRILL PLATFORM -
MSL
90 deg
GROUND SURFACE 2,605.70 ROCK SURFACE Not encountered BOTTOM OF HOLE 2,603.50 WATER lEVEl 2.0 m
DEPTH 0.00
SOIL TYPE      DESCRIPTION
SAMPLE
•TYPE 1 NO.
SIZE DEPTH RET’D
PENE TRATION TEST
Silty
clay
Silty clay with weathered fragments of basalt
Dark gray silty clay, greasy to floury texture, moist, highly plastic
Light gray silty clay to clayey silt with some partially wea thered white subrounded basaltic fragments, moist becoming with depth, highly plastic Bottom of auger hole
GZ
1       Bulk 0.30 
to
1.00
1.20
GS        2
Bulk 1.20 
to
2.20
wet
2.20
SAMPLING METHOD
•A - split tuOe
3 — tmn well rube
C - piston sampler
□ - core oarrei
INSPECTOR spyoum Lemma
E - auger
r - wasn
SHIPPING CONTAINER
N - i men
0 - xuoe
P - water content tin
Q - gias ar
R    -   ciotn oag
S-
Y-
(
plastic bag
core oox
discs raeo
LOGGED BY p, Valliappan, Said Mohammed
APPROVEO DATE
December'T.983
Form 318 A »1|Drilling Report
JOB P6888 HOLE AH-109 SHEET 1 OF 1
CLIENT
Ethiopian Electric Light and
Power Authority
(EELPA)
PROJECT
Aleltu Hydro Project
SITE
Jima Impervious Borrow Area
CONTRACTOR
Local labor
STARTED
13:00
21/11/83
FINISHED
17:00
21/11/83
METHOO OF
SOIL Augering with post hole
aucerCASING DIAM
DRILLING.
LOCATION:
ROCK     Not encountered
LATITUDE       ) DEPARTURE ) BEARING INITIAL DIP OTHER DIPS
See Impervious Borrow Area Drawing 90 deg
DEPTH 0.00
1.20
SOIL TYPE Silty 
clay
Silty 
clay          with weathered fragments
of basalt
DESCRIPTION
Dark gray silty clay, greasy to floury texture, moist, highly plastic
Light gray silty clay to clayey silt with some partially wea thered white subrounded basaltic fragments, moist oecoming wet with depth, highly plastic Bottom of auger hole
CORE OlAM
ELEVATIONS:     DATUM                           MSL
DRILL PLATFORM -
GROUND SURFACE 2,605.70
ROCK       SURFACE       Not       encountered BOTTOM OF HOLE 2,603.50
WATER LEVEL 2.0 m
PENE- SAMPLE________________________ TRATION
•TYPE NO. SIZE DEPTH RET'D TEST GZ 1 Bulk 0.30 
to
1.00 GS 2               Bulk 1.20 
to
2.20
2.20
SAMPLING METHOD
•A - spilt tube
0 - thin wall !um
C - onton sampler
□ - core carrel
INSPECTOR seyoum Lemma
e - auger
F - wasn
SHIPPING CONTAINER
N - insert
0 - tune
P - water content tin
Q — glass jar
R - ciotn oag
S - plastic nag
V - core box
Z — discarded
—________________
approve°
LOGGED 3V p Valliapoan, Said Mohammed
t
OATE Decemoer^Q 83
Porrn 318 A 111i 0DEID
ACCUMULATION OF BASALT BOULDERS THICK SOIL COVER ,OVER SOcml
THIN SOIL CO/ER I LESS THAN SOcm I WEATHERED BASALT
COLUMNAR JOINTEO BASALT
\ \ \ CLIFF FACE SLUMPING AT BOTTOM ___  GEOLOGICAL CONTACT OBSERVED ___ GEOLOGICAL CONTACT INFERRED
* TEST PIT
prrrg rock outcrop
NOTE
TOPOGRAPHY OBTAINED BY EELPA GROUND SURVEYS DURING PREFEASIBILITY FIELD INVESTIGATIONS IN I98S
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY ALELTU HYDROELECTRIC PROJECT
GEOLOGY OF TILIKU ALELTU DAM SITE
UIBELEVATION IN METRES
ET"»OHAN UtCTMC iK>l ANO *<OWI AuTMCWTt
M’U >
GEOLOGICAL SECTION OF M ZEGA WE Of M GORGE MGA
CLASSIFICATION OF SEDIMENTARY ROCKS
NOTE
JOINT MEASUREMENTS PLOTTED AS DIP AZIMUTH / DIP
SET DIP AZIMUTH DIP
1                   165’           68 345*          90
SPACING I mm i  BEDDING
VERT THINLY LAMINATED
JOINTING
U                  0S4°          87 2 14”         90
i 10
10-100
lOO-IOOO
OVER 1000
MEDIUM BEDDED
THICK MOOED
THINLY TO THICKLY LAMINATED
VERY THIN TO THINLY BEDDED
VERY CLOSE TO CLOSE JOINTED
ID                 065 ’          84 245’           89
MEDIUM JOINTED
WOE JOINTED
U                   282’           80
ETHIOPIAN ELECTRIC LIGHT ANO POWER AUTHORITY ALELTU HVDROELECTW,: pnclmct gagra GEOLOGIC STEREONETS WliFIGURE I
FIGURE 3
FIGURE 4
MAJOR TECTONIC FEATURES
LOCATION OF VOLCANIC CENTRES
LOCATION  OF  SEISMIC  EVENTS  OF MAGNITUDE 4
FIGURE 6
FIGURE 7
FIGURE 5
SOURCE OF INFORMATION
'EAR’HOUAKE   HISTORY   OF   E’HiOPiA   AND   ThE   HORN   OF   AFRICA" BY PIERRE GOU1N
INTERNATIONAL     OEVEuOpMENT     RESEARCH     CENTRE PUBLICATION No ilBE OTTAWA. CANADA 1979
PREDICTED GROUND ACCELARATION
PREDICTED INTENSITY
attenuation CURVES
C5
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY ALELTu HYDROELECTRIC PROJECT
SEISMICITY OF ETHIOPIA   UIBKILOMETRES
LOCATION MAP
SILTY CLAY
-SILTY CLAY WITH WEATHERED    FRAGMENTS
TP-107
OF BASALT
_        -p
I 2615 t
PLAN
SECTION A-A
METRES
SILTY CLAY-,
i SILTY CLAY WITH
WEATHERED FRAGMENTS
OF BASALT
-   2620 g
TP-100 AH-108 TP-101 Art’109
EL 2605?
EL 26024
-----------------
TP-102
EL26O69
-  2610 —
El 26049 El 2603 s
■ —TJT '------ r^~  4
\
EL 26045 /
WEATHERED BASALT
200                   400
600
1400                  1600                  1800
SECTION B-B
PLATE C-6
POTENTIAL JIMA IMPERVIOUS BORROW AREA  M8
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY
ALELTU HYDROELECTRIC PROJECT
AUGER HOLE 108c
oo                  <«
fcOa0
TiME U,NU’ES)
SWELL PRESSURE TEST TIME SWELL CURVE
B
PRESSURE .P ‘   /cn»* » CONSOLIDATION TEST e - Log P CURVE
OIRECT SHEAR TEST FAILURE ENVELOPE
PLASTICITY CHART
NOTE
C"MTT XX, STA0OLS "• "™ '"PCO •** CLASS* CATCH JTSTEM
5
8
i
GRAIN SIZE DISTRIBUTION
LEGEND
----------T»O2
---------r»K»
— - AH 109
IO2-III
ii si
io? ■ ?l ANO TP iOO IOE- lOI
--------- TR iOS
SWEU-iNS »»ES3u £ •«-
o
- ------- AH 109
103- l>
<02 1 II
SWELL CUPVE COR
PARTI ALL* CONFINED SWELL TEST
VARIATION OF UNDRAINED STRENGTH WITH
MOISTURE CONTENT
HORIZONTAL DISPLACEMENT I moil
DIRECT SHEAR TEST
STRESS DISPLACEMENT CURVES
—    - TP IDA
- - ah ior
iii 221
no- SI
--------- TPIOl l
OA KI
MOISTURE CONTENT t%>
---- ----- TP 100
IIO-ASl
STANDARD PROCTOR COMPACTION
TEST RESULTS
--------- AH OS I0S-2H
—  AH 109 - 2 22 I
"LA’E C
ETHIOPIAN ELECTRIC UGHT AND POWEP AUTHORITY AlEl’u HYOROE^ECTRir PwrufCT
PROPERTIES OF IMPERVIOUS MATERIALS
KIESJ
LIQUID LIMIT (%)
PLASTICITY CHART
NOTE
OART AND SYMBOLS ARE CROM UNFIED SOL CLASSIFICATION SYSTEM
1
RlvOlDCuWvE
COBBLES
GRAVEL
SAND
SILT OR CLAY
COAPSE  PINE
(
MEDIUM            PINE
________________ i--------------------
'□ARSE
GRAIN SIZE DISTRIBUTION
X • v
X2
LEGEND
---------------- TP 102  (02-1 •)
---------------to 102  (11-13)
-------------AH 109 (02-12) AND TP 100 (0 2-10)
---------------- TP 103  (03-1 I)
--------------- AH  108  (02-1 I)
--------------- AH  108  (i 1-22)
--------------- TP 104  (10-15)
------------------- TP  101    (04-16)
----------------TP 100  (10-46)
--------------- AH  105 (03-21)
--------------- AH  109 (I 2-22 I
PLATE C
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY
ALELTU HYDROELECTRIC PROJECT
PROPERTIES OF IMPERVIOUS MATERIALSLIQUID LIMIT (%)
PLASTICITY CHART
NOTE
CHART AND SYMBOLS ARE FROM UNIFIED SOL CLASSIFICATION SYSTEM
COBBLES
GRAVEL
SAND
SILT OR CLAY
COARSE ;NE
r
I MEDIUM ] FINE
COARSE
GRAIN SIZE DISTRIBUTION
LEGEND
------------ TP 102 (02-11)
------------- TP 102 (11-13)
-------------- AH 109    (02-12) AND  TP  100  (0  2-10) ------------ TP 103 (03-1.1)
-------------- AH 108 (02-1 I) -------------- AH 108 (1.1-22) ------------ TP 104 (1.0-15) ------------ TP IO» (04-16) -------------- TP 100  (I 0-46' ------------AH >05 (03-21) ------------ AH 109 (12-22)
PLATE C
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY ALElTU HYDROELECTRIC PROJECT
PROPERTIES OF IMPERVIOUS MATERIALSAPPENDIX D
TABLE OF CONTENTS
LIST   OF   TABLES LIST OF PLATES
Page
DI - WORK PROGRAM------------------------------------------------------------------------------  D- 1
D2 - DESCRIPTION OF THE PRESENT SETTING--------------------------------------------  D- 3
D3 - SHORT-TERM IMPACTS DURING CONSTRUCTION---------------------------------  D-18
D4 - LONG-TERM IMPACTS OF PROJECT-----------------------------------------------------  D-19
D5 - COST OF MITIGATING MEASURES------------------------------------------------------  D-26
PLATESAPPENDIX D
LIST OF TABLES
Number           Title
D. 1 Information on Farmer Associations
D.2
School Locations
D. 3
Health Care Services
D.4
Number      and      Percentage
of
Leading 
Causes for HospitalizationAPPENDIX D
LIST OF PLATES
Number    Title
D-l Environmental DefinitionsMay 28, 1984
APPENDIX D
SOCIOECONOMIC AND ENVIRONMENTAL ASSESSMENT
Construction o£ the Aleltu project will have various social
and environmental impacts on the surrounding community. With the extensive development of agriculture in the project area, 
the creation of reservoirs will have a significant impact on the local farmers in the Tiliku Aleltu and Jida basins. The construction of the power tunnel with its access adits and surge chamber, penstock, powerhouse and transmission line will also have an effect on the land use but being confined to smaller areas of impact can be more readily absorbed by the community.
This appendix presents a description of the local setting, identification of the major social and environmental issues, consideration of mitigating measures and identification of issues that should have additional assessment in the feasibility studies.
DI - WORK PROGRAM
As part of tnis study, social and environmental aspects of the project were reviewed. Tne investigation involved a site visit, acquisition of data from government agencies in Addis Ababa, and discussions with local officials and residents.D-2
From the site visit, it was possible to acquire considerable environmental information about the study area. With most of the area being used extensively for agricultural purposes, 
the major environmental issue was identified as being the inundation of grazing land and the resultant effects on the local farmers. Discussions with the local representative from the Ministry of Agriculture and information from the Bureau of Statistics were valuable in addressing this issue.
Contact With
Government Agencies
The main agencies contacted were the
- Planning Commission
(a)       General Statistical Office
(b)      Agricultural Statistics Office
(c)       Cartography Office
(d)       Ministry of Health
(e)       Ministry of Education
- Ministry of              Agriculture, Agriculture           Organization
Discussions were held in Muke Tun with
specifically Food and (FAO).
-   the local Ministry of Agriculture representative
- tne political representative for the Wuchale District
-   the general service representative for the Wuchale District.D-3
Other agencies identified for contact during the feasibility studies to develop detailed agricultural and rehabilitation programs are
-   Ministry of Urban and Housing Rural Project Agency
-   Science and Technology Commission
-   Agricultural and Industrial Development Bank
-   Addis Ababa University.
D2 - DESCRIPTION OF
THE PRESENT SETTING
(a) Land Use
The topography of the area in the vicinity of the proposed reservoirs is in general flat. As a conse quence, the area inundated with even low dams will be signif icant.
In the gorge, the topography is characterized by ver tical cliffs, natural terraces and shallow to steep soil covered slopes.
Within tne proposed project area on the plateau, virtually all tne available land is utilized for agri culture, either for crop cultivation or cattle grazing on natural pasture. In the gorge, the terraces and shallow slopes are farmed.D-4
Most of the people in the area are peasant farmers at
close to subsistence living. Each family farms 3 to 
4 ha, cultivating barley with some beans in the March to August period, and teff, wheat, barley, sorghum, chick 
peas and beans in the September to February period. The Ministry of Agriculture has tried, with little success
yet, to introduce the production of maize in the area. 
The main crops taken to market are barley and beans. Sedentary peasant livestock grazing occurs on unimproved pasture and fallow. Since the land is normally left
fallow for 4 to 10 years subsequent to intense cultiva
tion, considerable area for cattle grazing is available. 
Cattle are maintained for milk and meat. Herd sizes
vary, averaging 4 to 5 cattle per family with maximums
up to 20 cattle per family. Additional livestock 
includes sheep, goats, horses and donkeys. Oxen are maintained by some farmers for ploughing of the fields.
The housing settlement pattern of the farmers on the
plateau is important. The homes are generally in clus
ters, located on high land along the ridges of the
valleys and not down in the valleys. In general, the
houses are of a simple construction, wood pole frame
with thatch roofs and/or stone and mud or thatch walls. 
The land immediately adjacent to the homes is the most intensely cultivated with unimproved pasture occupying a larger proportion of the valleys.
Potable water is acquired from springs located near the homes. These springs are reported to flow even during 
the dry season.* The rivers are used to water the
Reported       by       tne       local       Ministry       of       Agriculture in Muke Turi.
representativeD-5
cattle but, apparently, not as a supply of potable water or for irrigation except in the vicinity of the Agat reservoir. In the Agat reservoir area, there is an 8-km canal, which was initially built for a flour mill in Debre Libanos. At present, it is being used for a very small power plant in the same area and for irrigation purposes along its length. The irrigated land produces mostly onions.
(b) Population
As a result of the recent national census, accurate information on the number of people in the study area is available. The actual location of peasant associations has been mapped by the General Statistical Office and should be finalized and available by March 1984.
Information on the farmer associations, including the names, number of members, major crops and types of animals raised in some of the districts potentially affected by the project, is shown in Table D.l. 
District boundaries are presented on Plate D-l.
The Debre Libanos District, which contains the Agat and Tinishu Aleltu basins, has approximately 6,375 people or 15.7 people per square kilometre. The Wuchale District, located south of the Debre Libanos District, contains
the entire Tiliku Aleltu and part of the Jida reser voirs. Although the Wuchale District nas a population of over 8,800 or 17.4 people per square kilometre, most of the settlements are located in the south and southcentral areas of the district. Population density 
in the area of tne Tiliku Aleltu and Jida reservoirs is sparse.TABLE D.1(a)
INFORMATION ON FARMER ASSOCIATIONS PROVINCE; Selale
DISTRICT:        Debre Libanos
Majoi Kind of Crop              Major
Name of Peasant
Major
Sep to
Mai to
Type of
Association
Member s
Occupation
Feb
Aug
Animals
Climate
Legend
Wayu
372
3
a,b ,c
c
k,l,n
P
1 - farming
Sele
328
3
a,b, c
c
k,l,n
P
2 - raise cattle
Timano
600
3
a,b,c
c
k,l ,n
P
3 - both
Sone
313
3
a f b, c
c
k,l,n
P
Fikre Seiam
Goro Gorone
130
481
3
3
d ,a
a,b
c
c
k ,m,n
k,l,n
Q,R
P
a - teff
b - wheat
Wortu
3 17
3
Kessim
d,b,a
c
k,l,n
P
c - barley
386
3
0
b, a, f
c
k, l,n
P
d - sorghum
Arabona Ayat
131
3
I
cn
a ,d
c
k ,m, n
Q,R
e - chick-pea
Auki Meselal
79
3
a,d,c
c
k, m, n
Q,R
f - beans
Set Debir
52
3
a,d,f
c
k,m,n
Q
g - nug
Zega Amel
149
3
a, d
c
k,m(n
R
Bussa
292
3
d ,a
c
o
P
k - cattle
Doiene
306
3
b,a,f
c
o
P
1 - sheep
Ji jiga
140
3
b,a,f
c
k,l,n
P
m - goats
Adis Alem
229
3
a, d, e
c
kn
Q,R
n - horses/donkeys
Hagere Selam
127
3
a,d,e
c
k ,m, n
Q.R
o - all
Gora Sbemen
229
3
a, b, e
c
o
p
Mukeara
342
3
c ,a
c
k, 1 ,n
p
P - cool zone
Edero
316
3
c, a,b
c
k, 1 ,n
p
Q - temperate zone
Babu Etaya
312
3
b, e
c
o
p
R - hot zone
Verero Aueguta
200
3
b, a, e
c
k,m, n
R,Q
Ji bo
284
3
b,a
c
o
P
Wero
260
3
a,b, c
c
k,l,n
P
TOTAL
6 375TABLE D.1(b)
INFORMATION ON FARMER ASSOCIATIONS
PROVINCE:        Selale
DISTRICT:         Wuchale
Major Kind of Crop              Major
Name of Peasant
Major
Sep to        Mar   to
Type     of
Association
Members
Occupation
Feb
Aug
Animals
Climate
Legend
Mechel a
185
3
c,f ,a
-
k. 1 ,n
P
1 - farming
Bole Gendem
222
3
a (b,c
-
o
Q
2 - raise cattle
Boseke Debir
130
3
a.b.c
-
k,l ,n
p
3 - both
Jibara
269
3
a,b, c
-
k  1  n
ff
p
date
213
3
a.b.c
-
k,l,n
P.Q.R
a - teff
Boseke
142
3
a, b, c
-
k,l,n
p
b - wheat
Duber Guto
180
3
a,b,c
-
k,l ,n
P.Q.R
c - barley
Duber Gebriel
24 1
3
a, b, c
-
k.l.n
p
d - sorghum
Webera
2 15
3
a,b,c
-
k.l.n
p
e - chick-pea
U
I
Tigrenobuko
595
3
a, b, c
-
k,l,n
p
f - beans
Kex eyu
171
3
a, bjC
-
k.l.n
p
g - nug
Adere Gordema
295
3
a, b, c
-
k.l.n
p
Dete Kot a
172
3
a, b, c, d -
k,l,n
p
k - cattle
Beeley Gimbichu
331
3
a, b, c
-
m
p
1 - sheep
Gel im
182
3
a,b,c
-
k.l.n
p
m - goats
Ellu Kora
257
3
a, b, c
-
k,l,n
p
n - horses/donkeys
Ado
2 29
3
a,b,c
-
k,l,n
p
o - all
Asomani
270
3
a, b, c
-
k.l.n
p
Botena Seyu
212
3
a, b,c
-
k,l,n
p
P - cool zone
Gorasa
203
3
a.b.c
-
k.l.n
p
Q - temperate zone
Ayu
196
3
a, b,c
-
o
P.Q
R - hot zone
Egu Kora
150
3
b,c, f
-
k.l.n
p
Babo Bedeyu
304
3
a, b  c f -
r#
o
Q
Deyu Gimbichu
818
3
a,b,c
-
o
QTable D.1(b)
Information on Farmer Associations - 2
PROVINCE:       Selale
DISTRICT:        Wuchale
Maj.or Kind of
Name of Peasant
Association
Members
Major
Occupation
Sep
Feb
to         Mar Aug
C F°P to
Major
Type     of
Animals Climate Legend
Akaku                                           223              3
Enguye Gerdo                              247              3
Adamana Deku                            250              3
Harcho                                          294              3
Becho Fanili                                 464              3
Becho Gorada
a f b g c / f — a,b,c,f
a,b,c,f
a,b,Cjf
a,bfc,f
o
k,l,n
k,l,n
k,l,n
k,    l,n
1  - farming
2  - raise cattle
3  - both
a - teff
247
3
a^bjCjf
o
k,l
b - wheat
Kaso Tulu
253
3
a,b# c,f
,n
c - barley
Nono Kore
376
3
a,b,c,f
k,l,n
k,l,n
d - sorghum
Kaso Aye
2 08
3
a , b t c, f -
e - chick-pea
Nono Boli
293
3
a,b,c,f
o
k,l ,n
f - beans
Mechela Andode
213
3
a t b / c g f —
TOTAL
8 830
g - nug
k - cattle
1 - sheep
m - goats
n - horses/donkeys
o - all
p - cool zone
Q - temperate zone
R - hot zone
I
1
iiTABLE D.1(c)
INFORMATION ON FARMER ASSOCIATIONS
PROVINCE:      Selale
DISTRICT:        Ensaro 
Major Kind of Crop
Name
of
Peasant
Members
173
Major
Occupation
3
Sep to
Feb
c,f ,b
Mar to
Aug
c,f
Major
Type
of
Association
Animals
Climate
Engoyu Arogi
108
263
3
3
c,f ,b
c / f i b
C/f
C/f
k,l,n
k,l,n
P
P
Legend
1 - farming
Tosegn
Ture
k,l,n
k,l,n
P
P
2 - raise cattle
3 - both
Enkuye Felelo
165
180
3
3
c,f ,b
c,f ,b
c,f
c,f
Bidano
Weserbi
91
146
3
3
c,f ,b
c,f ,b
c,f
c,f
k,l,n
k,l,n
P
P,Q,R
a - teff
b - wheat
k,l,n
P,Q,R
Abakasin
186
189
3
1
c,f ,b
c, f / b
c,f
c,f
k /1 / n
p
c - barley
d - sorghum
Esunaeteya
Kasem
Mute
201
194
1
1
c, f,b
c,f ,b
c,f
c,f
k,l
k,l
p
p
e - chick-pea
f - beans
Wekesir
181
302
1
1
b, a, c
b,a,c
c,f
c,f
k,l
k,l
p
Q
Denbana Egersa Leinina Munir
g - nug
k - cattle
Seielanami kerso
314
302
1
1
b, a, c
b,a,c
C/f
c,f
k,l
k,l
Q
Q
k,l
k,l
Q
Q
1 - sheep
m - goats
Kersanabisanera
Anzucha
Gi rarge
214
76
1
1
b, a, c
d, a,c
c,f
c,f
n - horses/donkeys o - all
Wegebnaaimg
176
216
1
1
d, a, c
d / a / c
C,f
C/f
k,l
k,l
R
Q,R
Welencheta Senketan
102
341
3
1
c,f
C/f
C/f
C/f
k,l
k,l,n
Q,R
Q
P - cool zone
Q - temperate zone
R - hot zone
Et nora Kena Amba
336
227
1
1
b,f ,a
b,f ,a
C/f
C/f
k,l ,n
k,l,n
R,Q
R
Hose
248
307
3
3
*/C,g
a,g
C/f
C/f
k,l,n k/1 ,m
R
P
Dawanakodiso
k/l/tn
P
Daugiorgis
217
491
3
3
ac
 # »f t g a,c,f,g
C/f
C/f
k, 1 ,m
P
Awarenabedaek
Digididara
251
260
1
1
a, d
a,d
C/f
C/f
k,l,m
m,k,l
P
R
Chewanamoraja
m,ki 1
m,k, 1
R
Kolamog
113
1
a,d
C/f
RTable D.1(b) Information on Farmer PROVINCE:     Selale DISTRICT:       Wuchale
Associations -
2
Major Kind of Crop Major
Name of Peasant Association
Members
Major
Occupation
Sep
Feb
to
Mar to
Aug
Type    of Animals
Climate
Legend
Akaku
223
3
a f b | c i f
o
Q
1 - farming
Enguye Gerdo
247
3
a,b,c,f
-
k,l,n
p
2 - raise cattle
Adamana Deku
250
3
a t b g c f f
-
k,l,n
p
3 - both
Harcho
294
3
a,b,c,f
-
k,l,n
p
Becho Fanili
464
3
a f b f c / f
-
k,l,n
R
a - teff
Becho Gorada
247
3
a,b,c,f
-
o
Q
b - wheat
Kaso Tulu
253
3
a,b,c,f
-
k,l,n
P.Q
c - barley
Nono Kore
376
3
a,b,c,f
-
*
k, l,n
P.Q
d - sorghum
Kaso Aye
2 08
3
a,b,c,f
k,l,n
p
e - chick-pea
Nono Boli
293
3
a,b,c,f
-
o
Q/R
f - beans
U
I
co
Mechela Andode
213
3
a,b,c,f
k,l ,n
P
g - nug
TOTAL
8 830
k - cattle
1 - sheep
m - goats
n - horses/donkeys
o - all
p - cool zone
Q - temperate zone
R - hot zoneTABLE D.1(c)
INFORMATION ON FARMER ASSOCIATIONS PROVINCE:    Selale
D1STRICT: Enaaro
Name     of     Peasant
Major
Major Kind of Crop Major
Sep to Mar to Type of
Association
Members
Occupation
Feb
Aug
Animals
Climate
Legend
Engoyu
173
3
c,f ,b
c,f
k,l,n
P
1 - farming
Arogi
108
3
c,f ,b
c,f
k,l,n
P
2 - raise cattle
Tosegn
263
3
c,f ,b
c,f
k,l,n
P
3 - both
Ture
165
3
c,f ,b
c,f
k,l,n
P
Enkuye Felelo
180
3
c,f ,b
C,f
k,l,n
P
a - teff
Bidano
91
3
c,f ,b
C, f
k,l,n
P,Q,R
b - wheat
Weserbi
146
3
c,f ,b
c,f
k,l,n
P,Q,R
c - barley
Abakasi n
186
3
c,f ,b
C,f
k,l,n
p
d - sorghum
O
Esunaeteya
189
1
c,f ,b
c,f
k,l
p
e - chick-pea
KO
I
Kasem
201
1
c,f ,b
c,f
k,l
p
f - beans
Mute
194
1
c,f ,b
c,f
k,l
p
g - nug
Wekesi r
181
1
b,a,c
C,f
k,l
Q
Denbana Egersa
302
1
b,a,c
C,f
k,l
Q
k - cattle
Lemina Munir
314
1
b / a f c
c,f
k,l
Q
1 - sheep
Selelanamikerso
302
1
b, a,c
c,f
k,l
Q
m - goats
Kersanabisanera
214
1
b, a,c
C,f
k,l
Q
n - horses/donkeys
Anzucha
76
1
d,a,c
c,f
k,l
R
o - all
Gi rarge
176
1
d,a,c
c,f
k.l
Q,R
Wegebnaaimg
216
1
d,a,c
c,f
k,l
Q,R
P - cool zone
Welencheta
102
3
c,f
c,f
k, 1, n
Q
Q - temperate zone
Senketan
341
1
c,f
C,f
k,l,n
R.Q
R - hot zone
Et nora
336
1
b,f ,a
C,f
k,l,n
R
Kena Amba
227
1
b,f ,a
C,f
k,l,n
R
Hose
248
3
a,c,g
c,f
k,l,m
P
Dawanakodiso
307
3
a,g
C,f
k,l,m
P
Daugiorgis
217
3
a,c,f,g
c,f
k,l,m
P
Awarenabedaek
491
3
a,c,f,g
C,f
k,l,m
P
Di gididara
251
1
a,d
C,f
m,k»l
R
Chewanamoraja
260
1
a,d
C/f
m,k,l
R
Koiamog
113
1
a,d
c,f
n>,k,l
RTable D.1(c)
Information on Farmer Associations - PROVINCE:     Selale
DISTRICT:       Ensaro
2
Major Kind of Crop            Major
Name of Peasant Association
Members
Major
Occupation
Sep to
Feb
Mar
Aug
to
Type of
Animals Climate Legend
Kor go go
340
1
a,d
Shenkora
c,f
m, k, 1
R
1 - farming
452
3
a, d
c,f
m,k,l
R
2 - raise cattle
Harowadeba
296
1
a,d
Harogulele
c,f
m, k, 1
R
3 - both
213
1
a, d
c,f
m,k,l
R
Kekersak i
448
3
a,b,f
c,f
m, k, 1
P
a - teff
Borebornak
283
3
a.b.c
C,f
m.k.l
P
b - wheat
Bikonadibi
366
3
a,b,f
c,f
m,k,l
P
c - barley
Aliberdada
265
3
a,b, f
C,f
m, k, 1
P
d - sorghum
Tulumilke
304
3
a,b,f
-
k,l,n
P
e - chick-pea
Aba Botro
358
3
a,b,f
-
k.l.n
P
f - beans
Jemjem Arbabo
425
3
d ,a
-
k,l,n
R
g - nug
Petona Sekekelo
358
3
d, a
-
k,m, n
R
Bochela
377
3
d ,a
-
k,m,n
R
k - cattle
Bobena Meda
267
3
d, a
-
k,m, n
R
1 - sheep
m - goats
TOTAL
11 322
n - horses/donkeys
o - all
p - cool zone
Q - temperate zone
R - hot zoneTABLE D.1(d)
INFORMATION ON FARMER ASSOCIATIONS PROVINCE:    Selale
DISTRICT: Girar Jersa
Major Kind of Crop            Major
Name     of     Peasant
Major
Sep to           Mar  to
Type    of
Associ at ion
Members
Occupation
Feb
Aug
Animals
Climate
Legend
Arje Gideyu
4 16
3
c,b,f
c,f
k,l ,n
P
1 - farming
Alamo Denka
266
3
c,b; a
c,f
k,l,n
P
2 - raise cattle
Selala Ali
183
3
c / b t a f f
c,f
k,l ,n
P
3 - both
Ana Chare
304
3
c,b,a,f
c,f
k,l,n
P
Bowana
2 39
3
c t b f a ( f
c,f
k,l,n
P
a - teff
Kano
371
3
c i b / a t f
c,f
k,l,n
P
b - wheat
Ameto
165
3
C;b,a,f
c,f
k,l,n
P
c - barley
Eras Osmani
363
3
c,b,a,f
-
k,l,n
P
d - sorghum
Eras Kino
250
3
c,b,a,f
-
k,l,n
P
e - chick-pea
Gishe Merche
272
3
c,b,a,f
-
k,l,n
P
f - beans
Sobo Abote
191
3
c,b,a,f
c,f
k,l,n
P
g - nug
Enta Denka
232
3
c,b,a,f
C|f
k,l,n
P
Etiso Boli
301
3
c,b,a,f
c,f
k,l,n
P
k - cattle
Shire Raso
258
3
c,b,a,f
C,f
k, l,n
P
1 - sheep
Setane Weldami
233
3
c t b f a i f
-
k,l,n
P
m - goats
Wert e
262
3
c,b,a,f
-
k,l,n
P
n - horses/donkeys
Enate Deneba
531
3
c / b t a / f
c,f
k,l,n
P
o - all
Chagal Ankaka
238
3
C;b,a,f
-
k,l,n
P
Kotuna Gobola
146
3
c,b,a,f
-
k,l,n
P
P - cool zone
Deyo Genda
300
3
a,b,c
-
k,l,n
Q
Q - temperate zone
Arere
229
3
a,b,c
-
k,l ,n
p
R - hot zone
Bego Kara
232
3
a, b, c
C,f
k,l,n
p
Shebel Beteri
275
3
a,b,c,f
c,f
k,l,n
p
Kolegna Eyesus
170
3
a,b,c,f
k,n,m
R
Selmi Zuria
550
3
a,b,c,f
c,f
o
Q,R
TOTAL
6 977D-12
Specific information on the size and population of districts to the east of Debre Libanos and Wuchale was not available. This information should be collated for future studies. For this prefeasibility study, it is sufficient to note that, as indicated by the topographic maps of the area and from the reconnaissance visit, the occurrence of settlements in this eastern area is
limited.
The reason for the lower population east of the Debre LiDanos District is probably a combination of restricted access (i.e., further distance from main roads) and poorer soil types. Although not confirmed, it appears that soils to the east tend to be more reddish in color, indicating the occurrence of chromic cambisols or eutric nitosols. According to FAO, these soils tend to support open grassland with peasant livestock grazing but not intense cultivation as occurs on the vertic cambisols and pellic vertisols in the western Agat reservoir area. Additionally, because of more rapid drainage of the soil in the eastern area, the cropping season may be shorter with lesser ability to endure drought periods.
(c)      Towns and
Large Villages
A number of towns or large villages are located within the area of influence of the project. These include Fiche, Debre Libanos, DeDre Tsige and Muke Turi.
Debre Libanos will require particular consideration being a historic religious center and the town closest to the proposed powerhouse access road and penstock.D-13
(d)       Religion
The predominant religion in the project area is
Ethiopian Orthodox. About 2 km from the start of the
access road to the powerhouse is a nationally famous
church in Debre Libanos. This church contains the tomb 
of the first Ethiopian saint, Abuneteklehaimanot, and 
the church is named after him.
Besides the famous church in Debre Libanos, there are
several other Ethiopian Orthodox churches throughout the
project area. There is also one Muslem settlement con
taining a mosque, located near Muke Turi just off the
road to Aleltu. The village is called Boku Tigre
suggesting the Tigray origin of the settlers.
(e)       Language
Generally,         about         three         different         languages         are         spoken         in the project area,
-    on the plateau—Oromo
-    in the gorge—Amharic
-    in towns—Oromo and Amharic mixed, and Tigrigna at the Muslem settlement near Muke Turi.
( f) Education
Schooling in the project is comparable to other rural regions in Etniopia. School locations and general information on size of schools, number of teachers and students in the project area, are presented in 
Table D.2.D-12
Specific information on the size and population of
I
districts to the east of Debre Libanos and Wuchale was
not available. This information should be collated for
future studies. For this prefeasibi11ty study, it is
sufficient to note that, as indicated by the topographic
maps of the area and from the reconnaissance visit, the
occurrence of settlements in this eastern area is
limited.
The reason for the lower population east of the Debre
Libanos District is probably a combination of restricted access (i.e., further distance from main roads) and 
poorer soil types. Although not confirmed, it appears tnat soils to the east tend to be more reddish in color, indicating the occurrence of chromic cambisols or eutric nitosols. According to FAO, these soils tend to support open grassland with peasant livestock grazing but not intense cultivation as occurs on the vertic cambisols and pellic vertisols in the western Agat reservoir area. Additionally, because of more rapid drainage of the soil in the eastern area, the cropping season may be shorter with lesser ability to endure drought periods.
(c) Towns and
Large Villages
A number of towns or large villages are located within the area of influence of the project. These include Fiche, Debre Libanos, Debre Tsige and Muke Turi.
Debre Libanos will require particular consideration being a historic religious center and the town closest to the proposed powerhouse access road and penstock.
-D-13
(d) Religion
The predominant religion in the project area is
Ethiopian Orthodox. About 2 km from the start of the
access road to the powerhouse is a nationally famous
church in Debre Libanos. This church contains the tomb 
of the first Ethiopian saint, Abuneteklehaimanot, and 
the church is named after him.
Besides the famous church in Debre Libanos, there are
several other Ethiopian Orthodox churches throughout the
project area. There is also one Muslem settlement con
taining a mosque, located near Muke Turi just off the
road to Aleltu. The village is called Boku Tigre
suggesting the Tigray origin of the settlers.
e) Language
Generally,         about         three         different         languages         are         spoken         in the project area,
-   on the plateau—Oromo
-    in the gorge—Amharic
-    in towns—Oromo and Amharic mixed, and Tigrigna at the Muslem settlement near Muke Turi.
f) Education
Schooling in the project is comparable to other rural regions in Etniopia. School locations and general information on size of schools, number of teachers and students in the project area, are presented in 
Table D.2.D-14
TABLE D.2
SCHOOL LOCATIONS*
Location
No. of
Area
District
Region
Schools
No. of
Students
No. of
Teachers
1
Ensaro
Selale
8
1 448
30
2
Debre
Libanos
Selale
11
1 665
38
3
Wuchale
Selale
9
1 758
39
4
Girar
Jarso
Selale
11
7 031
195
5
Sululta
Menagesha
14
3 746
83
6
Gida
Menagesha
4
965
14
7
Aleltu
Menagesha
5
1 530
31
8
Kimbibit
Tegulet
and Bulga
9
Bosena
Tegulet
and Bulga
21
9 965
277
10
Moja and Wadera
Tegulet
and Bulga
9
1 995
36
11
Moret and
Jiru
Tegulet
10
2 509
47
and Bulga
*For district location, see Plate D-l.D-15
(g) Health Care Services
The Aleltu project covers part of the twelve districts
in three provinces of the Shoa administrative region.
There is at least one health station in every district
of the project area, as shown in Table D.3. Healtn 
station locations are shown on Plate D-l.
Table D.4 gives a general idea of the type of diseases
in the administrative region in which the Aleltu project
is found.
(h) Wildlife and Fisheries
Wildlife
As a result of the extensive agricultural utilization 
of the area, most wildlife habitat has Deen disturbed, the exception to this being the Zega Wedem Gorge. Along the edge of the gorge, there are populations of the Gelada baboon, one of tne four endemic species to Ethiopia. The Gelada baboon, althougn concentrated in the High Semyen, has been noted at Debre Libanos (and Debre Lina areas with small populations in the Mulu and Bole Valley gorges). it is the only surviving representative of tne once widespread group of pri mates of the genus Thenopitnecus. Tne Gelada baboons have a linear distribution along tne escarpment never moving far from the rim. They are mainly vegetarian and very tame. Their only enemy is man wno sometimes snoots them for sport or to acquire the great mane of
tne adult male that is used for traditional head dresses by highland warriors.*
♦"Endemic Mamma1s of
Tourism Commission,
?noiopla
1 7 o 2 •'" Polished by tne EthiopianD-14
TABLE D.2
SCHOOL LOCATIONS*
Location
No. of
Area
District
Reg ion
Schools
No. of
Students
No. of
Teachers
1
Ensaro
Selale
8
1 448
30
2
DeDre
Libanos
Selale
11
1 665
38
3
Wuchale
Selale
9
1 758
39
4
Girar
Jarso
Selale
11
7 031
195
5
Sululta
Menagesha
14
3   746
83
6
Gida
Menagesha
4
965
14
7
Aleltu
Menagesha
5
1   530
31
8
Kimbibit
Tegulet
and Bulga
9
Bosena
Tegulet
21
9   965
277
and Bulga
10
Moja     and 
Tegulet
9
1   995
36
Wadera
and Bulga
11
Moret      and 
Tegulet
10
2   509
47
Jiru
and Bulga
*For district location, see Plate D-l.D-15
(g ) Health Care Services
The Aleltu project covers part of the twelve districts
in three provinces of the Shoa administrative region.
There is at least one health station in every district
of the project area, as shown in Table D.3. Health 
station locations are shown on Plate D-l.
Table D.4 gives a general idea of the type of diseases
in the administrative region in which tne Aleltu project
is found.
(h) Wildlife and Fisheries
Wildlife
As a result of the extensive agricultural utilization 
of the area, most wildlife habitat has been disturbed, the exception to this being the Zega Wedem Gorge. Along the edge of the gorge, there are populations of the Gelada baboon, one of the four endemic species to Ethiopia. The Gelada baboon, although concentrated in the High Semyen, has been noted at Debre Libanos (and Debre Lina areas with small populations in the Mulu and Bole Valley gorges). it is the only surviving representative of the once widespread group of pri mates of the genus Thenop1tnecus. The Gelada baboons have a linear distribution along the escarpment never moving far from tne rim. They are mainly vegetarian and very tame. Their only enemy is man who sometimes shoots them for sport or to acquire the great mane of
the adult male that is used for traditional head dresses by highland warriors.*
•"Endemic MammaIs of
Tourism Commission,
Etniopla, 1982.
published by tne EthiopianD-14
TABLE D.2
SCHOOL LOCATIONS*
Location
Area
District
Reg ion
No. o£
Schools
No. of
Students
No. of
Teachers
1
Ensaro
Selale
8
1 448
30
2
Debre Libanos
Selale
11
1 665
38
3
Wuchale
Selale
9
1 758
39
4
Girar
Jarso
Selale
11
7 031
195
5
Sululta
Menagesna
14
3 746
83
6
Gida
Menagesha
4
965
14
7
Aleltu
Menagesha
5
1 530
31
8
Kimbibit
Tegulet
and Bulga
9
Bosena
Tegulet
21
9 965
277
and Bulga
10
Moja and Wadera
Tegulet
9
1 995
36
and Bulga
11
Moret
and 
Tegulet
10
2 509
47
Jiru
and Bulga
*For district location, see Plate D-lD-15
(g) Health Care Services
The Aleltu project covers part of the twelve districts
in three provinces of the Shoa administrative region.
There is at least one health station in every district
of tne project area, as shown in Table D.3. Healtn 
station locations are shown on Plate D-l.
Table D.4 gives a general idea of the type of diseases
in the administrative region in whicn the Aleltu project
is found.
(h) Wildlife and Fisheries
Wildlife
As a result of the extensive agricultural utilization 
of the area, most wildlife habitat has been disturbed, 
the exception to this being the Zega Wedem Gorge. Along the edge of the gorge, there are populations of
the Gelada baboon, one of the four endemic species to Ethiopia. The Gelada baboon, altnough concentrated in the High Semyen, has Deen noted at Debre Libanos (and Debre Lina areas with small populations in the Mulu and Bole Valley gorges). it is the only surviving representative of tne once widespread group of pri mates of the genus Thenopithecus. The Gelada baboons have a linear distribution along the escarpment never moving far from tne rim. They are mainly vegetarian ana very tame. Their only enemy is man who sometimes shoots them for sport or to acquire the great mane of
the adult male that is used for traditional head dresses by highland warriors.*
*"Endemic Mamma Is of Ethiopia, Tourism Commission, 1982.
published by the EthiopianD-14
TABLE D.2
SCHOOL LOCATIONS*
Location
Area
District
Reg ion
No. of
Schools
No. of
Students
No. of
Teachers
1
Ensaro
Selale
8
1 448
30
2
Debre Libanos
Selale
11
1 665
38
3
Wuchale
Selale
9
1 758
39
4
Girar
Jarso
Selale
11
7 031
195
5
Sululta
Menagesna
14
3 746
83
6
Gida
Menagesha
4
965
14
7
Aleltu
Menagesha
5
1 530
31
8
Kimoibit
Tegulet
and Bulga
9
Bosena
Tegulet
and Bulga
21
9 965
277
10
Moja and Wadera
Tegulet
and Bulga
9
1 995
36
11
Moret
and 
Tegulet
10
2 509
47
Jiru
and Bulga
*For district location, see Plate D-lD—15
(g ) Healtn Care Services
The Aleltu project covers part of the twelve districts
in three provinces of the Shoa administrative region.
There is at least one health station in every district
of the project area, as shown in Table D.3. Health 
station locations are shown on Plate D-l.
Table D.4 gives a general idea of the type of diseases
in the administrative region in which the Aleltu project
is found.
(h) Wildlife and Fisheries
Wildlife
As a result of the extensive agricultural utilization 
of the area, most wildlife habitat has been disturbed, the exception to this being the Zega Wedem Gorge. Along the edge of the gorge, there are populations of the Gelada baboon, one of the four endemic species to Ethiopia. The Gelada baboon, although concentrated in the High Semyen, has been noted at Debre Libanos (and Debre Lina areas with small populations in the Hulu and Sole Valley gorges). it is the only surviving representative of tne once widespread group of pri mates of the genus Thenop1tnecus. The Gelada baboons have a linear distriDution along the escarpment never moving far from tne rim. They are mainly vegetarian and very tame. Their only enemy is man who sometimes shoots them for sport or to acquire the great mane of
the adult male tnat is used for traditional head dresses by nighland warriors.*
’"Endemic Mammals of Ethiopia," puolisned by tne Ethiooian Tourism Commission, 1982.D-16
TABLE D.3
HEALTH CARE SERVICES*
Name
of Health
Area
Station
(Town)
District
1              Hideno                     Ensaro
2               Lemi
Ensaro
Number
of Health Personnel**
Region Stations HA JHA CM
Selale 1 1 1 1 Selale 1 1 1 1
3              Debre Tsige             Debre
Libanos
Selale                   1
-11
4
Muke Turi
Wuchale
Selale
1
1
-
1
5
Silimi
Girar
Jarso
Selale
1
1
-
1
6
Aleltu
Aleltu
Menagesha
1
-
2
1
7
Gelayi
Gida
Menagesha
1
-
1
1
8
Gida
Gida
Menagesha
1
-
1
1
9
Senomulu
Sululta
Menagesha
1
-
1
-
10
Sheno
Kimbibit
Tegulet
1
1
2
1
11            Deneba                        Kimbibit
and Bulga
Tegulet
and Bulga
1
12              Gudo Beret            Moja   and          Tegulet
2--
2 1
Wadera
and Bulga
13
Seledingay
Moja   and
Tegulet
1 1
Wadera
and Bulga
14
Juhur
Moret and
Tegulet
1
1
1
1
Jiru
and Bulga
15
Keteb
Moret and
Tegulet
1
-
1
1
Jiru
and Bulga
16
Chacha
Angolala
Tiro
Tegulet
1
-
1
-
and Bulga
* For district and town locations, see Plate D-1.
••Personnel      descriptions      are      as      follows:      HA      -      Health      Assistance;      JHA Junior Health Assistance; CM - Custodial and Manual.
Note:        In other places in the project area, there are other health stations under construction. There is one hospital in Debre
Berhan.D—17
TABLE D.4
NUMBER AND PERCENTAGE OF LEADING CAUSES FOR HOSPITALIZATION
NO.                 Diagnosis
Number     Percent
1
Normal delivery
1 129
10.2
2
Malaria
836
7.6
3
Complications of pregnancy, childbirth and puerperium
647
5.8
4
Pneumonia (all types)
637
5.8
5
Dysentery (all types)
612
5.5
6
Tuberculosis (all forms)
571
5.2
7
Gastroenteritis and colitis
525
4.7
8
Transport accidents
255
2.3
9
Abortions
239
2.2
10
Malnutrition (all states)
219
2.0
Total Discharge
11 066
100.0
Note:         Ou$            the exPected 132 reports (hospital months),
only 56 were reported (Ministry of Health)
Information          obtained          from          Comprehensive          Health          Servin 
^■T^ r
8
11SBed °y
y and ProgrammingD-18
Fisheries
As a consequence of the ephemeral nature of the streams and lack of fish recruitment from downstream, it is expected that little or no fisheries exist in 
the streams in the impoundment areas.
D3 - SHORT-TERM IMPACTS
DURING CONSTRUCTION
Both detrimental and beneficial impacts will result from the construction of the project. Construction of access roads
and other structures, opening of borrow areas, and heavy construction traffic will disrupt some of the local farmers
and the village of Muke Tun, but should not deleteriously affect Debre Libanos or other towns and villages in the surrounding area. The influx of a migrant labor force will
also impose social pressures on the local communities and public health services. The possibility exists that diseases
not locally endemic can be introduced, with subsequent exposure of local residents. The detrimental impact of these activities can be controlled with appropriate planning and implementation of mitigating measures.
Employment opportunities for area residents, improved access, project purchases of local goods and services, housing rental and purchase by workers of locally produced goods could all be beneficial to the economy of the area and its residents. However, due to the subsistant lifestyle of most of the local residents, it will oe necessary to supply essential services
for any imported work force to ensure that an excess demandD-19
is       not       placed       on       the       local       supply       of       goods       and       services, especially food and medical requirements. With proper plan
ning,         construction         facilities,         such         as         a         hospital         and         school, can be converted into long-term beneficial facilities
subsequent to construction.
D4 - LONG-TERM
IMPACTS OF PROJECT
(a) Effects of Reservoirs
and Project Structures
on Farmers in the Area
As a consequence of the low relief of the area, any reservoir created will be relatively shallow and exten sive. Tinishu Aleltu is the only reservoir which would inundate any of the roads connecting the reservoir areas with Muke Turi. However, Tinishu Aleltu is not consi dered for development, at least in the Stage I construc tion.
With the extensive agriculture in the area, a consider able loss of farmland will occur with creation of tne reservoirs. The areas of the Tiliku Aleltu and Jida reservoirs are 7 and 52 km2 , respectively. This reservoir area presently forms part of a larger farming area whicn extends up to and beyond the houses on tne ridges. The larger farming area is estimated to cover about 150 to 200 km2 around the reservoirs. The farmers in this greater "area of direct influence" will be affected by the creation of the reservoirs with 59D-20
out of the 150 to 200 km2 lost to the reservoirs. 
This will be a 30 to 40% reduction in farming area in this area of direct influence. On a prorated basis, assuming a density of 16 people per square kilometre, this translates into 2,500 to 3,000 people directly or indirectly affected by the reservoirs in the Stage I development. Assuming 5 people per family, this becomes 500 to 600 families.
With the settlement patterns on the plateau (i.e., homes built on the ridge areas), the number of homes actually inundated will be small. However, the farmland around tne homes that would be inundated represents the liveli hood of the local people. As a consequence, it will be necessary co compensate the farmers. Although the land of 500 to 600 families will be affected, not all families will loose 30 to 40% of their land. Some will De only slightly affected such as having the boundaries of tneir farm changed to compensate them. Others will nave a larger extent of their grazing land disappear and will have to be substantially compensated. As they are peasant farmers, compensation in cash is not socially appropriate. Any development plan should include an intensive agriculture improvement plan and/or socially Deneficial rehabilitation and resettlement programs.
Several programs have Deen considered" as discussed Delow.
None of these programs are proposed as definite solutions but are presented to indicate that measures are available to mitigate the impact of the project. Recommended programs should be developed during the feasibility studies and, thereafter, in consultations with the local people, and responsible agencies both government and privateD—21
(i)      As peasant farmers, it is expected that most
would prefer to remain in the same community, even with smaller farm sizes, if they can con
tinue to maintain or improve their standard of living. A redistribution of farmlands, parti
cularly if some farmers elect to resettle else
where, as discussed below, should allow most farmers to continue with the existing farming practices. Farmers can be compensated for dis ruption and reductions in farm size by support programs including supply of (nonmechanized) farm equipment, tools, better housing, training pro grams and improved market access. These farmers grow cash crops and this would be an added benefit to such farmers.
(ii)         Since the soil has been derived from tertiary basalts and tuffs, it may be suitable for
upgraded agriculture.
Some peasant farmers may elect to remain in the same community and change their farming practice from subsistence to cash crop farming, if given appropriate support. This support could extend to supply of (nonmechanized) farm equipment, tools, better housing, training and use of ferti lizers and insecticides.
For example, a simple application of fertilizer on pasture land would increase the production capacity (cattle per hectare) of the land for grazing manyfold. This practice could more tnan compensate for the land inundated by the reservoirs.D-2 2
The agricultural extension service would have to extend over a period of 5 years or more to ensure that the farmers become self-supporting.
(iii)          Some farmers may accept resettlement in areas outside the community. A resettlement program would include transportation of family, belong ings and cattle; new housing; possible construc tion of access roads; and financial support for
one or more years until the new farm can be developed to self-sufficiency.
At the road junction near Sekoro, located between the Jida and Gomoro reservoirs, there is a rela tively new village—Weberi.* The agricultural representative in this village should be con
tacted regarding mitigation planning for the area farmers. It may also be possible to utilize the experience involved in developing this community to assist in any resettlement planning.
(b)       Effects Downstream
from Reservoirs
Downstream from the reservoirs, the natural river flows will De cut off after construction of the dams, except for local streams. Since the rivers are not used for
From discussions with the local people, the town was reformed around 1975 and it is now a village under the farmers association and under the Ensaro District.D-23
human activities, but mainly for watering cattle, the impact will not be severe. Watering holes can be pro vided for cattle along the river downstream from the dams. The watering holes can be supplied by releases from the reservoir or, since reservoir water is
extremely valuable, the watering holes would preferably be supplied by local tubewells providing the groundwater supply is sufficient. The feasiDility studies should address any localized impacts in areas where the rivers presently enter the gorge since there may be effects on inhabitants utilizing the terraces in these areas.
(c)       Effects on Religious
and Historical Monuments
The church at Debre Libanos need not and should not be affected by the development of the reservoirs, pen stocks, tunnels or powerhouse.
In the layout planning, particularly for the powerhouse access road and a penstock route which runs about 2 km west of Debre Libanos, special consideration was given to not disturbing the churches and holy areas. it is believed there would be no problems arising from the finally proposed project structure but this matter
should be diplomatically approached and confirmed in the feasibility study.
(d)       Impact on
Wildlife and Fisheries Wildlife
With          extensive          agricultural          development,          the          area          has precluded any significant wildlife utilization of theD-24
area. The only wildlife species of concern is the
Gelada baboon. The main effect on its habitat will be
in the area where the tunnel/penstock enters the
gorge. This area should be investigated to determine
if any minor relocations are warranted to reduce the impact to any areas used extensively by the Gelada baboons.
Fisheries
Since present fisheries populations are expected to be small or nonexiscant, anticipated impacts are not of concern. With the creation of the reservoirs, a
fisheries development program should be investigated; however, with the drawdown anticipated in most (or all) of the reservoirs, such a program may not be
viable.
(e)       Potential for Aquatic
Macrophyte Development
With the cooler climate in the area and the proposed extensive annual drawdown, the likelinood of developing an aquatic macrophyte problem is lessened. However, since the reservoir would be shallow and result from the inundation of agricultural land, a program to monitor
weed development should be implemented during the early phases of the project with a contingency plan prepared 
to properly deal with any weed problems if they do materialize.
The swamps in tne headwaters of the Tiliku Aleltu and Jida reservoirs should be surveyed for nuisance species that could inoculate the reservoirs.D-25
If open channels are used co connect the reservoirs, 
they should be designed to discourage macrophyte growth. This could include concrete lining, adequate flow, steep sides and/or weed collection/removal facilities. The present canals in the Agat reservoir area should be investigated in this context.
f) Infectious Diseases
Schistosomiasis, often resulting from reservoir development in tropical conditions, appears to be vir tually nonexistant in the project area. This is prob
ably due to the lack of standing water bodies, the
regular occurrence of droughts, cooler climate and a dispersed population. With the creation of the reser
voir and the need for resettlement, it is possible that Schistosomiasis could become a problem if not monitored and controlled. The occurrence of snails of the genuses Bulinus, Biompharlaria and Oncomelania, the intermediate host for Schistosomiasis, should be monitored with a contingency plan developed as shown in Table D.4.
Malaria does occur in the area. For protection of both the indigenous population and the construction work force, a malaria control program should be established prior to start of construction.D-24
area. The only wildlife species of concern is the
Gelada baboon. The main effect on its habitat will be
in the area where the tunnel/penstock enters the
gorge. This area should be investigated to determine
if any minor relocations are warranted to reduce the impact to any areas used extensively by the Gelada baboons.
Fisheries
Since present fisheries populations are expected to be small or nonexistant, anticipated impacts are not of concern. With the creation of the reservoirs, a
fisheries development program should be investigated; however, with the drawdown anticipated in most (or all) of the reservoirs, such a program may not be
viable.
(e) Potential for Aquatic
Macrophyte Development
With the cooler climate in the area and the proposed extensive annual drawdown, the likelihood of developing an aquatic macrophyte problem is lessened. However, since the reservoir would be shallow and result from the inundation of agricultural land, a program to monitor
weed development snould be implemented during the early phases of the project with a contingency plan prepared 
to properly deal with any weed problems if they do materialize.
The swamps in the headwaters of the Tiliku Aleltu and Jida reservoirs should oe surveyed for nuisance species that could inoculate the reservoirs.D-25
If open channels are used to connect the reservoirs, 
they should be designed to discourage macrophyte growth. This could include concrete lining, adequate flow, steep sides and/or weed collection/removal facilities. The present canals in the Agat reservoir area should be investigated in this context.
f) Infectious Diseases
Schistosomiasis, often resulting from reservoir development in tropical conditions, appears to be vir tually nonexistant in the project area. This is prob
ably due to the lack of standing water bodies, the
regular occurrence of droughts, cooler climate and a dispersed population. With the creation of the reser
voir and the need for resettlement, it is possible that Schistosomiasis could become a problem if not monitored and controlled. The occurrence of snails of the genuses Bulinus, Biompharlaria and Oncomelania, the intermediate host for Schistosomiasis, should be monitored with a contingency plan developed as shown in Table D.4.
Malaria does occur in the area. For protection of both the indigenous population and the construction work force, a malaria control program should be established prior to start of construction.D-26
D5 - COST OF
MITIGATING MEASURES
As a result of construction of the Aleltu project, various mitigating measures will have to be implemented, as discussed above. The cost of these measures is charged to the
project.
(a) Rehabilitation/
Resettlement Program
The major social cost will be for renabilitation and/or resettlement associated with the loss of agricultural land. Allowing for implementation of a combination of the rehabilitation and/or resettlement programs discussed in Section D4, the cost is estimated at, on average, $9,000 per family in the area of influence.
This cost for 500 to 600 families totals about
$5 million.
(b) Other Social and
Environmental Programs
Other costs to mitigate the impact of the project will arise with respect to downstream compensation health control programs, modest wildlife and fisheries pro grams, and other social improvements in the area. An estimate of these total requirements and cost is beyond the scope of this prefeasibility study. To allow for
these measures, a provisional sum of $3 million has been provided in the cost estimate for Stage I.D-27
The total socioenvironmental cost, which is carried forward to the cost estimate in Appendix E, is as follows.
Rehabilitation/Resettlement Program $5,000,000 Other Socioenvironmental Programs
TOTAL
3,000,000 $8,000,00059*
yr sc
»— • 0-00’
.^INEWARE
YIDENO
I
4- 9-45
tqpfe r e
Xg, r
\
TSIG0
ANOSW L J®j|
< Jr1                Wj* <■*     1
MUKE
"UR I
/
/
/
9" 3C /
I
I
I
I
I
SENOMULU
JCHANCHQ
GELAY I
\
I
I'
ORAINAGE
BASIN LIMITS
SENDAFA
ADDIS
PLAN
9*00
10
LEGEND
— PROVINCIAL BOUNDARY
_________DISTRICT BOUNDARY
® HEALTH CARE SERVICES
NOTE
NOT ALL
VILuAGES WITH
HEALTH stations are SHOWN ON THE MAP
ETHIOPIAN ELECTRIC LIGHT AND POWER AUTHORITY
Plate D-*
ENVIRONMENTAL DEFINITIONS MiIlS
ALELTU HYDROELECTRIC PROJECT lilflYIDENO
U<
1
>MUKE                 jF j . < v / : A. - 1 ’
t TUT r
k X
1 ’V' <z'-
OA
i /I
H
( SENOMULU
:hancho
GELAYI
SHENO
DRAINAGE 8ASIN LIMITS
SENDAFA
ADDIS
SiBfa z
PLAN
9-00
* uOMFHtfS
LEGEND
— PROVINCIAL BOUNDARY district BOUNOARY HEALTH care services
note
not al*, villages with HEAltH stations are shown on the map
ETHIOPIAN ELECTRIC LIG--H--T---A-,NLD/wPcOn WauEihROAHUITTYHO--R---IT--Y------------------------------------------- 1 AlELTU HYDROELECTRIC project lUra
PLATE CH
ENVIRONMENTAL DEFINITIONS nilHliAPPENDIX E
COST ESTIMATE
This appendix contains the detailed cost estimate at prefeasibility level of the first stage of the Aleltu 
project.
The code of accounts of the estimate contains the following main items.
00 Infrastructure
01 Reservoir
02 Interconnection Tunnel
03 Dams
04 Spillways
05 Power Tunnel Intake
06 Power Tunnel
07 Surface Penstock
08 Powerhouse
09 Switchyard
10     Socioeconomic Costs
11     Transmission
12     Gafarsa SuDstation
in the estimate, the quantities, unit prices and construct
costs, based on January 1984 price levels
•Lcvexs, are shown. 
» 
°n
Contingencies vary between 15 and 25# and are inclnc „
tne individual cost items. The average contingency Lunts" co 20.7%. Engineering, construction management and owner-, cost were assumed to oe aoout 12% and are included in thE-2
The estimate covers all direct and indirect items for implementation of the first stage of the project within the ICS, and includes for construction power and socioeconomic programs, all transmission and substation costs. Interest
and escalation during construction is not included. The estimate is presented in the following tables.E-3
APPENDIX E
STAGE 1
PREFEASIBILITY COST ESTIMATE
6 x 50Nm Units
PAGE: 1 OF 7
jteh sub
DESCRIPTION
QUANTITY
UNIT
UNIT PRICE
AMOUNT
TOTAL
REMARKS
(4/
(I)
00
INFRASTRUCTURE
J
ACCESS ROADS
.11
TO DAN SITES
4
KM
50,000
200,000
.12
TO POWERHOUSE AND TUNNEL OUTLET
.121
STEEP CLIFF ACCESS
2.5
KM
1,000,000
2,500,000
.122
WINDING SIDE HILL
6
KM
500,000
3,000,000
Ind. S/Yard Access
.123
FLAT
5.5
KM
100,000
550,000
.13
TUNNEL ROAD i SUR6E TANK ACCESS
20
KM
50,000
1,000,000
.14
CONSTRUCTION SITE ROADS
10
KM
30,000
300,OuO
.15
ROAD MAINTENANCE
-
LS
**
500,000
,2
CONSTRUCTION AND CAMP POWER
.21
ELECTRICAL POWER SUPPLY 4 OPERATION
-
LS
-
2,000,000
Ind. standby diesel
▼
.J
OIL STORAGE DEPOTS
-
LS
-
500,000
.4
CONSTRUCTION CAMPS
.41
MAIN CAMP
.411
SITE DEVELOPMENT 4 SERVICES
-
LS
2,000,000
.412
H0USE5
130
EA
40,000
5,200,000
.413
BUNKHOUSES k LOW INCOME HOUSING
-
LS
-
1,500,000
.414
KITCHEN/DINER/COMMISSARY
-
LS
-
2,500,000
.415
RECREATION HALL/CLUBHOUSE
-
LS
-
1,000,000
.41b
FIRST AID/MEDICAL FACILITIES
-
LS
-
2,000,000
.417
SCHOOL/OPERATE
-
Ind. operation
LS
-
1,000.000
.410
OTHER BUILDINGS
-
LS
-
1,000,000
.42
SECONDARY CAMP AT POWERHOUSE
LS
4.000,000
.43
CAMP OPERATIONS
.431
MAINTENANCE
-
LS
-
1,000,000
.432
SECURITY
-
LS
-
1,000,000
.433
FOOD 4 CATERIN6/CAMP MANAGEMENT
1.900,000
ND
8.00
14,400.000
.5
CONTINGENCY
-
LS
-
11,790.000
Approx. 251
SUBTOTAL 00
-—————
58,940,000
01
RESERVOIR
.1
RESERVOIR CLEARING
-
LS
■J
NONE REQUIRED
2                TREATMENT OF CONTACT ZONES ’ILIKU-ALELTU
77                J IDA
-
-
LS
LS
• *
CONTINGENCY
-
450,uOO
-           1.200.000 450,OuO
Approx. 251.
SUBTOTAL 0!E-2
The estimate covers all direct and indirect items for implementation of the first stage of the project within the ICS, and includes for construction power and socioeconomic programs, all transmission and substation costs. Interest
and escalation during construction is not included. The estimate is presented in the following tables.E-3
N SUB
APPENDIX e
STAGE 1
°REFEASIBILITY COST ESTIMATE b x 50H« Units
DESCRIPTION
PAGE: 1 OF 7
QUANTITY        UNIT       UNIT PRICE             AMOUNT
(1)
If)
TOTAL
«)
REMARKS
INFRASTRUCTURE
.1               ACCESS ROADS
.11             TO DAM SITES
.12                  TO POWERHOUSE AND TUNNEL OUTLET
.121                    STEEP CLIFF ACCESS
.122                     KINDINS SIDE HILL
.123                    FLAT
.13                TUNNEL ROAD i SURGE TANK ACCESS
.14                CONSTRUCTION SITE ROADS
.15                ROAD MAINTENANCE
.2                CONSTRUCTION AND CAMP POKER
.21                ELECTRICAL POKER SUPPLY i OPERATION
.3                OIL ST0RA6E DEPOTS
.4               CONSTRUCT ION CAMPS
.41 MAIN CAMP
.411              SITE DEVELOPMENT A SERVICES
.412              HOUSES
.413              BUNKHOUSES 4 lON INCOME HOUSING
.414          KITCHEN/DINER/CONMISSARY
.415          RECREATION HALL/CLUBHOUSE
,41o               FIRST AID/MEDICAL FACILITIES
.41?              SCHOOL/OPERATE
.418               OTHER BUILDINGS
.42               SECONDARY CAMP AT POWERHOUSE
.43                CAMP OPERATIONS
.431               MAINTENANCE
.432               SECURITY
.433               FOOD I CATERIN8/CAMP MANAGEMENT
.5 CONTINGENCY
SUBTOTAL 00
4     KN                      50,000                200,000
2.5       KN                 1,000,000           2,500,000
6       KN                    500,000           3,000,000
5.5       KN                    100,000                 550,000
20       KN                      50,000           1,000,000
10       KN                      30,000                 300,000
Inci. S/*ard Access
-       LS
-                 500,000
-       LS
-       LS
- 2,000,000
- 500,000
Ind. standbv diesel
-        LS
- 2,000.000
130
EA
40,000              5,200,000
-
LS
-              1,500,000
-
LS
-              2,500,000
-
LS
-              1 000 000
-
LS
,,
- 2 000 000
-
LS
,,
1 000 000
Ind. operation
-
LS
,,
- 1 000 000
-
LS
,,
4,000,000
-
LS
-              1 000 000
-
LS
,,
- 1 000 000
1,800,000
MD
8.00
,,
14,400,1)00
-            11,790,000
Approx. 25Z
----------
59,’40,000
RESERVOIR
.1 RESERVOIR CLEARING
LS
-
.2
TREATMENT OF CONTACT ZONES
•W RESUIRED
,2i
TILIKU-ALELTU
.22
JIDA
lS
-
LS
450,000
1,200,000
CONTINGENCY
450,000
SUBT0T4L 01
------------
100,00^
H PPrcx. 2S/.E-4
SUB
APPENDIX E
STAGE I
PREFEASIBILITY COST ESTIMATE o x 50Mn Units
DESCRIPTION
QUANTITY        UNIT      UNIT PRICE                AMOUNT             TOTAL
REMARKS
<$)
(11 ($)
INTERCONNECTION TUNNEL (Ind. Low Level              Outlet)
.1
MAIN TUNNEL
.11
PORTALS
.111
OPEN CUT ROCK EXCAVATION
120,000
M3
15.00
1,300,000
.112
SURFACE TREATMENT
-
LS
-
100,000
.113
REINFORCED CONCRETE
1,500
M3
350.00
525.000
bi dia.
.12
T UNNEL
.121
ROCK EXCAVATION
57,000
M3
70.00
3,990,000
.122
ROCKBOLTING t STEEL SUPPORT
-
LS
-
200,000
.13
GUIDES,STOPLOGSIHOISTS
-
LS
-
880,000
.14
REMOVAL OF ROCK PLUG
-
LS
-
30,000
’.2                  LON lEVEL OUTLET TUNNEL
.21
TUNNEL AND SATE CHAMBER
.211
TUNNEL AND CHAMBER EXCAVATION
15,000
M3
75.00
1,125,000
.212
ACCESS SHAFT EXCAVATION
500
M3
200.00
100,000
5a dial.
.213
ROCKBOLTING & STEEL SUPPORT
-
LS
-
100,000
Raise
.214
REINFORCED CONCRETE
150
M3
500.00
75,000
.22
OUTLET PORTAL
.221
OPEN CUT ROCK EXCAVATION
14,000
M3
15.00
210,000
.222
ROCK SURFACE TREATMENT
-
LS
•
20,000
.223
REINFORCED CONCRETE
500
M3
350.00
175,000
.23
GUIDES, GATES, HOISTS, LINER
-
LS
-
1,300,000
.3                 CONTINGENCY
SUBTOTAL 02
-       LS
-           2,120,000
Approx. 20Z
.1
TILIKU-ALELTU DAM
.11
COFFERDAMS i UNNATERING
-
lS
200,uUO
. -i
EXCAVATION I FOUNDATION PREPARATION
.12:
COMMON EXCAVATION
70,000
.122
CORE TRENCH EXCAVATION
15.000
N3
N3
123
FOUNDATION PREPARATION
9,000
N2
3.50
10.00
10.00
Belew core
.124
6R0UTIN6
-
LS
245,000
150,000
90,000
500,000
Grout curtain
.13
DAM FILLS
.131
COMPACTED IMPERVIOUS CORE
175,000
4Ki naui
.132
COMPACTED FILTER
80,000
P 0CeS5B3
r
.133
COMPACTED TRANSITION
215,000
M3
KJ
M3
5.u0
15.00
10.00
Screened
.134
COMPACTED ROCKFILL
.134!
FROM EXCAVATIONS
400,000
N3
5.U0
.1342
QUARRIED
250,000
M3
M3
J
12. UO
2,000,000
3,000,000
.135
RIPRAP
40,OOU
10.00
4U0,000
100,000
F o« excavations
r
.14
INSTRUMENTATION
-
aE-5
APPENDII E
STA6E 1
°REFEASIBILITY COST ESTIMATE
PAGE: 3 OF 7
6 x 50N. Units
ITEM sub
description
QUANTITY unit unit price
MOUNT                TOTAL
REHARK5
if)
If)
(f /
I
I
I
I
I
I
I« H
R
P
.2
.21
.22
• •
.222
.223
.224
.23
.231
.232
.233
.234
.235
.24
.3
JIDA DAM
COFFERDAMS & UNWATERING EXCAVATION & FOUNDATION PREPARATION
COMMON EXCAVATION
CORE TRENCH EXCAVATION FOUNDATION PREPARATION GROUTINS
DAM FILLS
COMPACTED IMPERVIOUS CORE COMPACTED FILTER COMPACTED TRANSITION COMPACTED BASALT ROCKFILL RIPRAP
INSTRUMENTATION CONTINGENCY
SUBTOTAL 03
-        LS
230,000        M3
65,000        M3
44,000        112
-        LS
900,000        H3
400.000        «3
875,000        M3
4,790,000        M3
145,000        M3
LS
-        LS
-        200,000
3.50 805,000
10.00
10.00
-
t>50,000
440,000
1,500,000
Below core
5.00                 4,500,000
15.00
10.00
6,000,000
9,750,000
10.00               47,900,000
10.00
•
1,450,000
200,000
SKi naul Processed
Excav. nearby Frca tunnel excav
-               16,655,000
Approx. 201
99,960,000
SPILLWAYS
.1 TILIKU RESERVOIR SPILLWAY
.11                  EXCAVATION
.111
.112
.12
.13
COMMON
ROCK
CONCRETE
SURFACE TREATMENT
18,000
95,000
M3
M3
150 M3
LS
5.00
15.00
300.00
90,000
1,425.000
45,000
150,000
.2 JIDA RESERVOIR SPILLWAY
.2!                   EXCAVATION
.211
.212
.22
.23
COMMON
ROCK
CONCRETE
SURFACE TREATMENT
26,000
120,000
M3
M3
100        M3
LS
-         IS
5.00
15.00
300.00
130,000
1,800,000
30,000
150,000
.3                    CONTINGENCY
SUBTOTAL 04
- 960,000
'
.
^oprcx 251
<.780,000
POWER TUNNEL INTAKE
EXCAVATION
COMMON
OPEN CUT ROCK
ROCK SURFACE TREATENNT
5.000 N3
50,000 M3
-•
00
- uS
l5 -°0
25,000
750.000
75.000
REINFORCED CONCRETE
M3
350.00
BRIDGE ACCESS It DECK
- IS
420,000
300,^00E-6
I TEH SUB
APPENDIX E
STAGE 1
PREFEASIBILITY COST ESTIMATE o x 50Mw Units
DESCRIPTION
PAGE: 4 OF 7 QUANTITY       UNIT      UNIT PRICE               AMOUNT              TOTAL
REMARKS
111
($)
.4
GUIDES, SATE5 I HOISTS
.41
GUIDES 4 EMBEDMENTS
-
LS
-
350,000
.42
TRASHRACKS
-
LS
-
105.000
.43
BULKHEAD SATE
-
L5
-
25,000
.44
CONTROL GATE
-
LS
-
50,000
.45
HOISTS
-
LS
-
55,000
For control 4 service ga
.5                 CONTINGENCY
SUBTOTAL 05
-       LS
-              535.000
Approx. 251
2,o90,000
06
POWER TUNNEL (INCL.SURGE TANK 4 VALVE CHAMBER?
.1 ACCESS ADITS, NUCKIN6 SHAFTS, AND IWIN TUNNEL
.11
ACCESS ADITS
.111
PORTAL
-
LS
-
300,000
.112
TUNNEL
.1121
EXCAVATION
20,UDO
H3
75.00
1,500,000
One adit ® 5i du.
.1122
ROCK BOLTING 4 STEEL SUPPORT
-
LS
-
100,000
.113
ADIT PLUG 4 HISC.
-
LS
-
1UU.00G
10
• A ±
ACCESS 4 MUCKING SHAFTS
.12!
.1211
ROCK EXCAVATION
SINKING SHAFTS
ROCK SUFPORT
3,000
-
M3
LS
300.00
-
900,000
200,000
Two shafts
.1212
. 122
LOCAL concrete support
750
M3
350.00
262,500
.123
SHAFT EQUIPMENT
-
LS
-
500,000
.124
PLUG SHAFTS
-
LS
-
40,000
.13
MAIN TUNNEL
.131
ROCK EXCAVATION-TUNNELS
165,000
M3
120.00
19.800,000
3.oo Gia.
.132
ROCK EICAVAT1ON-SHAFT
4,000
MJ
200.OG
500,000
.133
ROCKBOLTING 4 STEEL SUPPORT
-
LS
-
900,000
.134
CONCRETE
.1341
LINING OF HORIZONTAL TUNNELS
52,000
H3
250.ou
3,000,000
.1342
LINING OF VERTICAL SHAFT SECTIONS
1,000
M3
350.00
350,000
.1343
CONCRETE BEHIND STEEL LINING
3,000
M3
160.OC
5«o,ooo
.1344
OVERBREAK CONCRETE
33,000
H3
HO. 00
4,-20,000
.14
STEEL LINING
1,500
tonne
3,000
4,500,000
.15
VENTILATION 4 MISCELLANEOUS
-
LS
-
1,000,000
SURGE SHAFT I TANK
.21
POCK EXCAVATION
.211
SINKING PILOT SHAFT
1.900
M3
200.00
380,000
use *or ouckinq 4 access
• •- * V
ENLARGEMENT CQR TANK
n?
..3
30.000
13
50.00
1.500,UOO
ROCK SUPPORT
-
LS
-
340,uOO
Bolting i steel rings
CONCRE’E
23’
.INING OF SHAFT
100
MJ
350.00
35.000
TANK
3,500
MJ
300.00
1,050,000
.24
SUPERSTRUCTURE
-
LS
-
500.000E-7
APPENDIX E
STA6E 1
PREFEASIBILITY    COST    ESTIMATE 6 x 50Nv Units
DESCRIPTION
QUANTITY UNIT UNIT PRICE
AMOUNT
IS)
PA6E: 5 OF 7
TOTAL
IS)
RENARKS
(S)
VALVE CHAMBER
CIVIL WORK
ROCK EICAVATION
3, uOO
M3
50.00
150,UOO
ROCK SUPPORT
-
LS
-
50.000
REINFORCED CONCRETE
500
M3
400.00
200,000
MECHANICAL
VALVE
-
LS
-
980,000
One spherical valve
STEEL LINER
LS
-
100,000
2.4a da. x 30a Ig.
CONTINGENCY
-
LS
-
9,912,500
Approx.201
SUBTOTAL 06
59,510,000
SURFACE PENSTOCK
ROCK EICAVATION
30,000
2,500
5,800
M3
CONCRETE ANCHORS
25.00
40U.00
3,000
750,000
1,000,000
17,400,000
750,OuO
Trench
M3
STEEL PENSTOCK
Incl. saoale support
RAIL SYSTEM
tonne
LS
Ind. aamfoid
2ki lg.
CONTINGENCY
-
lS
-
2,930,JOO
15X
SUBTOTAL 07
22,930,000
POWERHOUSE
EICAVATION
COMMON
ROCK(POWERHOUSE i TAILRACE; SLOPE EICAVATION
SLOPE STABILIZATION
RE1NFCRCE0 CONCRETE
15,000 M3
40,000 M3
<00.000 M3
45,000 M2
5.)0                   75,000
25.00           1,000,000
5,u0          2.000,000
<00 180,000
Na Dlastmg, «aCn. exca
1L500 M3
EMBEDDED METAL3/P!PING
400.00
- LS
4,&00,0Q0 300,000
SUPERSTRUCTURE It ARCHITECTURAL
1,300 M2
<200
1,750,000APPENDIX E
STAGE 1
PREFEASIBILITY COST ESTIMATE 6 x 50Mw Units
DESCRIPTION
PAGE: 4 OF 7
ITEM SUB
QUANTITY
UNIT       UNIT PRICE          AMOUNT If)                       (4)
TOTAL
if)
REMARKS
.4
GUIDES, GATES i HOISTS
.41
GUIDES 4 EMBEDMENTS
■ LS
-
350.000
.42
TRASHRACKS
lS
-
105,000
.43
B'JLKHEAD SATE
L5
-
25,000
.44
CONTROL GATE
LS
-
50,000
.45
HOISTS
LS
-
55,000
For control & service ga
.5                 CONTINGENCY
-       LS
-              535,000
Approx. 253
SUBTOTAL 05
2,690,000
06
POWER TUNNEL (INCL.SURGE TANK 4 VALVE         CHAMBER)
.1
ACCESS ADITS, RUCKING SHAFTS, AND MAIN TUNNEL
.11
ACCESS ADITS
.111
PORTAL
-
LS
-
300,000
.112
TUNNEL
.1121
EXCAVATION
20,000
M3
7S.OO
1,500.000
One adit § 5i flu.
.1122
ROCK BOLTING 1 STEEL SUPPORT
-
LS
-
100,000
.113
ADIT PLUG i MISC.
-
IS
-
100,000
.12
ACCESS 4 MUCKING SHAFTS
.121
ROCK EXCAVATION
.1211
SINKING SHAFTS
3,000
M3
300.00
900,000
t mo shafts
.1212
ROCK SUPPORT
-
LS
-
200,000
. 122
lOCAL CONCRETE SUPPORT
750
M3
350.00
262,5U0
.123
SHAFT EQUIPMENT
-
LS
-
500,000
.124
PLUG SHAFTS
-
LS
-
40.000
.. j
i-
MAIN TUNNEL
.131
ROCK EXCAVATION-TUNNELS
165,000
M3
120.00
19.300,000
3.3ft did.
.132
ROCK EXCAVATION-SHAFT
4.000
M3
200.00
800,00V
.133
POCKBOLTING I STEEL SUPPORT
-
LS
-
900,000
.134
CONCRETE
.1341
LINING OF HORIZONTAL TUNNELS
32,000
MJ
250.00
3,000,000
.1342
LINING OF VERTICAL SHAFT SECTIONS
1,000
M3
350.UO
350,000
.1343
CONCRETE BEHIND STEEL LINING
3,000
M3
ISO.00
540,000
.1344
OVERBREAK CONCRETE
33.000
M3
140.00
4,520,000
.14
S”EEL l!N!N6
1,500
tonne
3,000
4,500,000
15
VENTILATION 4 MISCELLANEOUS
-
LS
-
1,000,000
n                 SURGE SHAFT j TANK
n,
. -A
POCK EXCAVATION
!
SINKING PILOT SHAFT
1,900
M3
200.00
380,000
use *or tucking ? access
•»• ▼
ENLARGEMENT ^OR TANK
30,000
M3
50.00
1,500,000
•>2
ROCK SUPPORT
-
IS
-
340.000
Bolting 4 steel rgs
r
CONCRETE
.INING OF SHAFT
100
M3
350.00
35.000
TANK
3,500
M3
300,90
1,050,000
.2<
SUPERSTRUCTURE
-
LS
-
500,000E-7
APPENDIX E
STAGE 1
PREFEASIBILITY COST ESTIMATE 6 x 5OM* Units
DESCRIPTION
PA6E: 5 OF 7
1 SUB
QUANTITY        UNIT        UNIT PRICE               AMOUNT
TOTAL
if)
REMARKS
(S)
(S)
.3
VALVE CHAMBER
.31
CIVIL WORK
.311
ROCK EXCAVATION
3.000
M3
50.00
150,000
.312
ROCK SUPPORT
-
LS
-
50.000
.313
REINFORCED CONCRETE
500
M3
400.00
200,000
.32
MECHANICAL
.321
VALVE
-
LS
-
880,000
One spherical valve
.322
STEEL LINER
-
LS
-
ioo.ooo
2.4b oia. x 30a lg.
.4                CONTINGENCY
-        LS
-               9,912,500
Approx.2CZ
SUBTOTAL Oo
59,510,000
SURFACE PENSTOCK
.1
ROCK EXCAVATION
30,000
M3
25.00
7 50,OoO
Trench
.2
.3
CONCRETE ANCHORS
2,500
5,800
M3
STEEL PENSTOCK
400.00
3,000
2,000,000
17,400,000
Ind. saadle support
tonne
Ind, tamfalfl
.4
RAIL SYSTEM
-
LS
-
750,000
2K« lg.
c
• u
CONTINGENCY
-
LS
-
2,980,000
15X
SUBTOTAL 07
22,380,000
POWERHOUSE
.1
EXCAVATION
.11
COMMON
15,000
M3
5.00
? 5,000
.12
.13
ROCK(POWERHOUSE i TAILRACE)
SLOPE EXCAVATION
40,000
400,000
M3
M3
25.00
5.00
1, 000,GOO
No alasting.    n. exca
2,000,000
Jac
.2
.3
SLOPE STABILIZATION
REINFORCED CONCRETE
45,U00
11,500
M2
M3
4.00
<00.00
180,000
4,600,juO
.4
EMBEDDED METALS/PIP ING
-
LS
300,000
.5
SUPERSTRUCTURE i ARCHITECTURAL
1,300
M2
1,200
1,750,000E-8
ITEM SUB
APPENDIX E
STAGE I
PREFEASIBIL1TV COST ESTIMATE o x 5CMb Units
DESCRIPTION
PAGE: o OF 7
QUANTITY
UNIT     UNIT PRICE             AMOUNT
TOTAL
iS)
REMARKS
ill
(f/
• 0                 ELECT/MECH EQUIPMENT
.61
MECHANICAL
.611
INLET VALVES
0
EA
315.000
1.990,000
o§la au. soheriul
.el2
3ATES/SUIDES/H0ISTS
. 0 i 21
DISCHARGE PIT GATE
-
LS
-
’,000
1
.0122
DISCHARGE DIT GUIDES
-
lS
-
76,uO0
o sets
.6123
DISCHARGE PIT GATE HOIST
-
lS
-
7.000
I
.613
T URBINES 4 GOVERNORS
0
EA
2,150,000
12,900.000
5utH ei. Delten wneei
.□14
POWERHOUSE CRANE
-
LS
-
535,000
sot
.□15
PQKRHOUSc BECh SERVICES
-
LS
-
1,450,000
.o2
ELECTRICAL
.□21
GENERATORS 4 EXCITERS
0
EA
2,400,000
14,400,000
.622
MAIN TRANSFORMERS
-
LS
-
J.0v0,000
.623
POWERHOUSE AUXILIARY ELECTRICAL
-
LS
•
4,0o0,00U
•t
./
CONTINGENCY
-
LS
-
9.630.000
Aoorox. 203
SUBTOTAL 08
57,800.000
?
SWITCHYARD
.1                CIVIL WORKS 4 FOUNDATIONS ,C                SWITCHYARD EQUIPMENT
.3                CONTINGENCY
SUBTOTAL O’ SOCIOECONOMIC PROGRAMS PROVISIONAL SUM CONTINGENCY
SUBTOTAL 10
- LS
- LS
- LS
800,000
-       7,200.000
1,600,000
Aoprox.2< 9.600.000
- LS
LS
- fe.400.0U0
-          l.oOO.OOv
Aporox. 251 9,000,u00
TRANSMISSION
.1          TRANSMISSION          LINES
.11                POWERHOUSE TO PLATEAU
,12                 PLATEAU TO ADDIS iGAFARSA) CGNTIN5ENC
SUBTOTAL 11
3 KM                  200,000 600,000
S5 f.M
lS
100.000         8,500,000 1.320.000
Apprcx.2Gl
;0,92'j.000C4 U
IT0 SUB
APPENDII E
STAGE I
PREFEASIBILITY COST ESTIMATE 6 x :0Mw Units
DESCRIPTION
E-9
QUANTITY                 UNIT UNIT PRICE                    AMOUNT
PAGE: 7 OF 7 TOTAL
REMARKS
(i)
•$>
SAFARSA SUBSTATION
.1 CIVIL NORKS I FOUNDATION
- LS
800,000
SNITCHGEAR
TRANSFORMERS
- lS
-
7,200.000
- LS
3,000,000
.4 CONTINGENCY
- LS
-
2,200.000
Approx.20'
SUBTOTAL 12
13,200,000
TOTAL CONSTRUCTION COSTS (00 to 12) ENGINEERING 1 CONSTRUCTION MANAGEMENT OWNER S ADMINISTRATION
TOTAL ESTIMATED COST
363,130.000
16,310,000 Approx. LOZ 7,260,000 Approx. 2Z
40o,700,000
♦OTHER COSTS (Not Included)
» I. D. C. EscalationAPPENDIX F
TABLE OF CONTENTS
Page
Fl - GENERAL----------------------------------------------------------------------------------------- F“ 1
F2 - OBJECTIVE AND GENERAL APPROACH
OF THE FEASIBILITY STUDY----------------------------------------------------------  F" 1
F3 - SCOPE OF CONSULTING SERVICES-----------------------------------------------------  F" 3
F3.1 - Update of Reconnaissance Study---------------------------------------------------  F- 3
F3.2 - Feasibility Studies--------------------------------------------------------------------  F- 4
F3.2.1        - Investigation of the Selected Site------------------------------------------  F-         4
F3.2.2        - Layout of the Project---------------------------------------------------------  F-         5
F3.2.3         - Power and Energy------------------------------------------------------------  F—      6
F3.2.4         - Transmission Capability ----------------------------------------------------  F—      7
F3.2.5 - Environmental and Socioeconomic
Studies---------------------------------------------------------------------  F-         7
F3.2.6 -          Construction Planning and Scheduling----------------------------------  F- 9
F3.2.7 -          Capital Cost Estimate ------------------------------------------------------  F- 9
F3.2.8 -          Economic Evaluation of
the Project --------------------------------  F-10
F3.2.9 - Financial Studies -----------------------------------------------------------------  F-13
F3.3 - Reporting------------------------------------------------------------------------------------  F-13APPENDIX F
TABLE OF CONTENTS
Page
Fl - GENERAL------------------------------------------------------------------------------------------ F" 1
F2 - OBJECTIVE AND GENERAL APPROACH
OF THE FEASIBILITY STUDY-----------------------------------------------------------  F- 1
F3 - SCOPE OF CONSULTING SERVICES------------------------------------------------------  F- 3
F3.1 - Update of Reconnaissance Study---------------------------------------------------  F- 3
F3.2 - Feasibility Studies---------------------------------------------------------------------  F- 4
F3.2.1 -           Investigation of the Selected Site-----------------------------------------  F-
4
F3.2.2 -           Layout of the Project-------------------------------------------------------  F-
5
F3.2.3 -           Power and Energy----------------------------------------------------------  F-
6
F3.2.4 -           Transmission Capability --------------------------------------------------  F—
7
F3.2.5 - Environmental and Socioeconomic
Studies---------------------------------------------------------------------  F-
7
F3.2.6        - Construction Planning and Scheduling-------------------------------------  F- 9
F3.2.7 
- Capital Cost Estimate -------------------------------------  F— 
9
F3.2.8            - Economic Evaluation of the Project-------------------------------------
F-10
F3.2.9 
F3.3 -
- Financial Studies ------------------------------------------  F-13 Reporting------------------------------------------  F-13
1
I
1
I
I
I
I
IAPPENDIX F
TERMS OF REFERENCE
Fl - GENERAL
EELPA wishes to carry out a feasibility study of the Aleltu project for the purpose of
-   determining if the Aleltu project should be considered for meeting the increasing load demand in the ICS, and the timing of the project for implementation
-   arranging financing for engineering and construction from international financing institutions.
F2 - OBJECTIVE AND GENERAL
APPROACH OF THE
FEASIBILITY STUDY
The principal objectives are
- to determine the technical and the first stage of development
economical feasibility of of the Aleltu hydro projectF-2
-   to determine tne least-cost generation and transmission sequence of development for tne Aleltu project for meeting the expected load demands in the ICS
-   to perform a financial analysis of the recommended project.
The studies should be separated in two distinct phases. The first phase consists of a comprehensive review and update of the reconnaissance study of the ultimate development. From this first pnase study, the first stage of development for
tne Aleltu project should be confirmed.
The second phase of the study consists of a review of the prefeasibility study of the first stage of development, confirmation of its findings and carrying out of the feasibility study.
The consultant shall review all reference material, including the PPS, OctoDer 1982, and the Aleltu Hydro Project, recon naissance and prefeasibility studies, June 1984, noting and addressing the recommendations in the latter report for future studies.
The studies for the hydroelectric development snail include
-   detailed investigations of topography, geology and hydrology
-   project layout, including preliminary design of the access road to the powerhouse
-   study of the transmission system
-   environmental and socioeconomical studies
-   construction planning, including contract packaging and construction schedule
-   estimated cost of the workF-3
-   development of alternative generation and transmission sequences
-   economic analysis
-   financial studies.
The studies mentioned above will be carried out using method ologies which will permit consideration for the eventual financing of the project by international financing agencies.
The consultant should perform all surveys, analysis and collection of data, and engineering work as may be required to attain the objectives set out and to meet all professional standards. In the conduct of his work, the consultant should cooperate and liaise fully with EELPA.
The
and
and
consultant should  be solely  responsible interpretation  of all data obtained  and recommendations of his report.
for          the          analysis the conclusions
F3 - SCOPE OF CONSULTING SERVICES
The studies will include the activities described below.
F3.1 - Update of
Reconnaissance Study
A large number of development schemes of the Aleltu project were identified in the reconnaissance phase of the 1984 reconnaissance and prefeasibility studies. Although most of these schemes were investigated, an accurate definition ofcue development sequence was not possible due to limited availability of 1:50 000-scale mapping and detailed topographic data.
The sizing of the first stage of the Aleltu project will be influenced by tne future development of the ultimate project. Therefore, the ultimate development must be investigated and sufficiently defined to determine the provisions in the first stage for the ultimate development. The scope of work required will De to
-   review the proposed layouts for all schemes (using new 1:50 000-scale mapping in these areas for which only 
1:250 000-scale mapping was available)
-   carry out full topographic surveys of the proposed reser voirs and dam locations, in order to confirm or adjust volume-elevation curves and firm flow calculations
-   prepare revised cost estimates, if necessary, and determine the optimum development sequence of the ultimate development
-   establish tne effect of this sequence on the proposed first stage of development
F3.2 - Feasibility Studies
F3.2.1 - Investigation of
tne Selected Site
The investigations started in the Aleltu project area during the initial reconnaissance and prefeasibilityF-5
studies       must       De       updated       and       extended       to       provide       all
the        data        necessary        for        the        conceptual        designs        which 
are to be prepared as part of the feasibility study.
-   The design study of the project must be based on 
topographic surveys of high precision. The surveys
shall establish points of reference for the control
of alignment and level during the investigations of
the recommended site, and for subsequent construc
tion activity.
-   The geological and geotechnical investigations will
include field mapping, drill holes, exploration
adits,  geophysical surveys,  test pitting  and  labora tory  tests.  The studies will include an  analysis of seismological data and  estimations on  the magnitudes of earthquakes.
- All the hydrologic and meteorologic data available must be analyzed and evaluated for the determination of significant flow parameters, such as long-term average flow, characteristics of the flow in wet and dry years, seasonal and monthly variations of the flows, evaporation losses from the reservoirs, mag nitude and frequency of floods. Data on the trans port of sediments will be required to permit an evaluation of the sedimentation of tne reservoir.
F3.2.2 - Layout of the Project
Studies of project layout will be carried out to determine the best layout and design of all tne components of the hydroelectric project, tne access roads, transmission lines and substations. All theF-4
t le development sequence was not possible due to limited availability of 1:50 000-scale mapping and detailed topographic data.
The sizing of the first stage of the Aleltu project will be influenced by the future development of the ultimate project. Therefore, the ultimate development must be investigated and sufficiently defined to determine the provisions in the first stage for the ultimate development. The scope of work required will be to
-    review the proposed layouts for all schemes (using new 1:50 000-scale mapping in these areas for which only 
1:250 000-scale mapping was available)
-    carry out full topographic surveys of the proposed reser voirs and dam locations, in order to confirm or adjust volume-elevation curves and firm flow calculations
-    prepare revised cost estimates, if necessary, and determine tne optimum development sequence of the ultimate development
- establish the effect of
stage of development
- define the second stage of the Aleltu
F 3.2 - Feasibility Studies
F3.2.1 - Investigation of
tne Selected Site
this sequence
on the proposed first project.
Tne investigations started in the Aleltu project area
during the initial reconnaissance and prefeasibilityF-5
studies must be updated  and  extended  to  provide all the data necessary  for the conceptual designs which are to be prepared as part of the feasibility study.
-   The design study of the project must be based on topographic surveys of high precision. The surveys shall establish points of reference for the control
of alignment and level during the investigations of the recommended site, and for subsequent construc tion activity.
-   The geological and geotechnical investigations will include field mapping, drill holes, exploration 
adits, geophysical surveys, test pitting and labora tory tests. The studies will include an analysis of seismological data and estimations on the magnitudes of earthquakes.
- All the hydrologic and meteorologic data available must be analyzed and evaluated for the determination of significant flow parameters, such as long-term average flow, characteristics of the flow in wet and dry years, seasonal and monthly variations of the flows, evaporation losses from the reservoirs, mag nitude and frequency of floods. Data on the trans port of sediments will oe required to permit an evaluation of tne sedimentation of the reservoir.
F3.2.2 - Layout of the Project
Studies of project layout will be carried out to determine the best layout and design of all tne components of the hydroelectric project, tne access roads, transmission lines and substations. A11 tneF-6
structures and facilities will be defined with sufficient detail to permit the calculation of
quantities and preparation of the cost estimate for
a feasibility level of study.
The optimum dimensions, capacities and principal characteristics of all major project components (civil works, mechanical and electrical equipment) for power production shall be determined in evaluation of the competing alternatives.
Selection of all individual project components should be determined by economic comparisons. Where necessary, the level of detail of site investigations should be such as to allow proper comparisons of alternative developments.
Location and dimensions of major structures for the recommended project should be firmly establisned. The access road required for construction and operation of the powerhouse should be surveyed and designs snould be prepared to include alignment, grade, surfacing and sections so tnat the route is firmly established.
Transmission and substation requirements at Addis Ababa shall be included in the studies and layouts for the Aleltu project.
F3.2.3 - Power and Energy
Power and energy calculations shall be performed in conjunction with evaluation of alternative sequences for best development of the project within the ICS.F-7
F3.2.4 - Transmission Capability
The consultant shall delineate the transmission development alternatives and conduct load flow, short circuit and stability studies to ensure adequate performance of the recommended network and its components under maximum and minimum system load conditions for the initial and extended power plant capacity.
The studies of the transmission line will determine
-   the selected voltage level and the number of lines, taking into account quantities of energy at present and in the future to be transmitted and the
stability of the system
-    the type and level of compensation if required.
F3.2.5 - Environmental and
Socioeconomic Studies
The potential impact by construction of the project
and creation of the reservoirs will include the
following considerations.
(a) Environment
An environmental study will be carried out to estimate me impact which will occur from the construction and operation of the project, and to determine the necessary means to avoid or to alleviate the environmental problems which are identified. The environmental study will includeF-8
construction and operation of the project, and to determine the necessary means to avoid or to alleviate the environmental problems which are identified. The environmental study will include assessment of the impact of the project on the aquatic and terrestrial ecology of the region.
Biomedical studies will be carried out to estimate the potential of various human disease vectors which could occur from the construction and operation of the project, and to determine
the necessary means to avoid or to alleviate the disease problems which are identified.
(b) Socioeconomic
Socioeconomic studies will be carried out to evaluate the social and socioeconomic impact, particularly on tne local population, from the construction and operation of the project. Execution of tne socioeconomic studies will include
- socioeconomic survey of population which would be affected directly and indirectly by the
Aleltu project
-   assessment of land which would be directly influenced by the project reservoirs
-   assessment of religious areas which are of particular importance and may be affected by the project.F3.2.6 - Construction planning
and Scheduling
The consultant will arrange the work into appropriate contract packages and will prepare engineering and construction schedules showing the activities of EELPA, the engineer and the contractors. The schedule shall include all major structures and activities
required for implementation of the project, including land acquisition, buildup of infrastructure and socioeconomic programs. Engineering and construction supervision should be shown as a separate contract. For each contract package, the consultant shall indi cate the preengineering requirements of EELPA, and the engineering and management planning for initiating the project.
F3.2.7 - Capital Cost Estimate
The estimate of cost will contain tabulations of quantities, unit prices and total cost for all the
principal items.
All direct and indirect costs which may occur in construction and completion of the project will be included. The cost of each major project item should be made up of base costs and physical contingency, and these should be broken down into local currency and foreign exchange. Components in foreign currency will also be defined for products manufactured locally which contain within their costs imported components making up a significant portion.F-10
The estimated cost of the recommended project should 
be broken down into the major procurement and con struction contracts, and also possible financing 
packages. A program of cash flow must be presented 
for all the major components of the project with price escalation and interest during construction shown separately. Cash flows should also be provided for
local currency and foreign exchange separately.
F3.2.8 - Economic Evaluation
of the Project
The economic evaluation will be carried out on the
basis of the performance of the Aleltu project in the
ICS.
(a)       Load Forecast
The forecasted demands of energy and system peak capacity will be provided to the consultant by EELPA. The basic economic evaluation will be performed for the most probable forecast, with sensitivity tests carried out for optimistic and pessimistic cases.
(b)       Development of
Alternative Generation
and Transmission Sequences
The consultant should define alternative sequences, with and without Aleltu, for providing generation and transmission capacity to meet the forecasted demands over the study period for theF-l 1
ICS. Prior to defining the generation and trans mission components of the sequences, the consul tant should review the capability of the existing system, and all the known primary generation resources of the country which appear to De economically attractive for the power production. The consultant should consider and take due note of the expected lives of the existing plant in 
the country.
The studies should define firm capacity and energy production, and secondary energy consider ing the useful storage and the interrelated operation of the reservoirs in the ICS. Each sequence of development shall be comparable both in terms of reliability.
In evaluation of the alternative sequences, the study will determine how the energy produced by the various projects (particularly the Aleltu project) can best be used in the ICS, taking into account the characteristics of the present installation and the future planned installa
tions, and to establish the installed capacity 
and the capacity factor of the plants.
(c) Economic Methodology
The economic analysis of the Aleltu hydroelectric project will De carried out using the net present value method to determine the least-cost program of a number of alternative generation sequences witn and without the Aleltu project.F-10
The estimated cost of the recommended project should 
be broxen down into the major procurement and con struction contracts, and also possible financing 
packages. A program of cash flow must be presented 
for all the major components of the project with price escalation and interest during construction shown separately. Cash flows should also be provided for
local currency and foreign exchange separately.
F3.2.8 - Economic Evaluation
of the Project
The economic evaluation will be carried out on the
basis of the performance of the Aleltu project in the
ICS.
(a) Load Forecast
Tne forecasted demands of energy and system peak capacity will be provided to the consultant by EELPA. The basic economic evaluation will be performed for the most probable forecast, with sensitivity tests carried out for optimistic and pessimistic cases.
(b) Development of
Alternative Generation
and Transmission Sequences
The consultant should define alternative sequences, with and without Aleltu, for providing generation and transmission capacity to meet the forecasted demands over the study period for theF-ll
ICS. Prior to defining the generation and trans mission components of the sequences, the cons
tant should review the capability of the existing system, and all the known primary generation resources of the country which appear to be economically attractive for the power production. The consultant should consider and take due note of the expected lives of the existing plant in 
the country.
The studies should define firm capacity and energy production, and secondary energy consider ing the useful storage and the interrelated operation of the reservoirs in the ICS. Each sequence of development shall be comparable both in terms of reliability.
In evaluation of the alternative sequences, the study will determine how the energy produced by the various projects (particularly the Aleltu project) can best be used in the ICS, taking into account the characteristics of the present installation and the future planned installa
tions, and to establish the installed capacity and the capacity factor of the plants.
c) Economic Methodology
The economic
analysis of the Aleltu hy
project will De carried out
value method to determine the least— of a number of alternative generati
droelectric using 
tne
net
present
cost p
rogram
on 
seque
nces
with and without tne Aleltu
project.F-12
-   The analysis will De based on constant value and estimated prices applicable to a fixed date close to the end of the study.
-   The calculation of costs must include invest ment capital, operating fuel costs, fixed costs of operation and maintenance, and interim replacement and equivalent insurance.
-   The economic analysis of the project must be made using both market (actual) and economic (shadow) prices, and taking into account non- quantifiable aspects. The difference between the analysis based on market prices and that based on economic prices for each category affected will be presented in a table.
-   The sensitivity of the results should be examined with respect to changes in the values of all important parameters, e.g., load forecast, discount rate, capital and operating costs.
-    Differential escalation of any major cost item, such as hydrocarbon fuels, snail be identified and the affect of the differential escalation versus constant prices shall be examined.
-   The net present value, internal rate of return and tne benefit/cost ratio for the recommended sequence of development and competitive alter natives shall be presented in the study 
report.F-13
F3.2.9 - Financial Studies
The financial analyses must take the form of a financial forecast during the assumed economic life of the project. Criteria for the financing of the pro posed project will be assumed in consultation with EELPA, and this, together with estimates of capital costs, and costs of operation and maintenance, will be used to determine the tariff required for the sale of electrical energy to achieve the assumed financial objectives. The financial analysis will be performed on the basis of
-    the project by itself
-   the project as a part of EELPAs overall program for generation and transmission in the country.
The financial assumptions established  provisions of agencies.
used        will        conform        with        the international lending
The financial requirements will be expressed in current money terms, taking into consideration escala tion of present prices. The effects of different
rates of inflation on the financing of the project must be determined.
F3.3 - Reporting
A s a minimum, the consultant is expected to meet formally with EELPA on the following occasions
- after 1 month—to review
the consultant's
cions and to discuss and
agree the detaileo
initial ooserva- work. planF-14
-    after about 3 months—to review the load forecasts, the existing and potential generation plants and the proposed criteria for evaluation of alternatives
-    after about 6 months—to review the consultant's early results and the likely future course of the study, and to discuss the proposed outline of the final report, etc
-    to review study progress and findings immediately before preparation of the draft report commences
- to review the consultant's draft report.
On or before submission of the Draft Final Report, the consultant will be expected to give a formal presentation in Ethiopia to EELPA and others, outlining the study and its results and recommendations.
The consultants shall prepare and submit the following reports to EELPA within the time periods indicated.
Report
Progress Reports Draft Final Report Final Report
Timing
At intervals of 2 months
15 months from starting date Within 30 calendar days of
receipt of comments on the Draft Final Report from EELPA
All reports shall be in English.F-15
Progress Reports
Progress reports shall contain
-   a brief summary fo the work accomplished in the preceding 
2 months
-   an outline of work expected to be completed during the
next progress reporting period
- the consultant's comments or recommendations on any
unforeseen conditions that may affect the progress or
quality of their work.
Final Report
Conclusions and  recommendations shall be on  a firm basis from which  EELPA can  make decisions on  implementation  ot the project in the ICS.
The technical and economical feasibility studies tor the hydroelectric development of the Aleltu project will be complete and presented with sufficient detail to servo to support applications for financing to an international lending agency.
Training of
Counterpart Personnel
The Consultant snail work in collaboration with EELPA in the training of counterpart personnel for the transfer of technology with respect to most aspects of tne study. The Consultant shall provide training Dotn in Etniopia and in the Consultant's home office by working on a daily basis with tne counterpart personnel. Provision snail be made

Summery

Project Overview

The document presents reconnaissance and prefeasibility studies for the Aleltu Hydroelectric Project in Ethiopia, conducted by Acres International Limited in June 1984. The study comprises three volumes, with Volume 3 containing technical appendixes.

Key Components

Layout Optimization Model: Mathematical model for reservoir system design and operation
Hydrological Studies: Analysis of streamflow, rainfall, and flood data
Geological Investigations: Site evaluations and seismic assessments
Socioeconomic & Environmental Assessment

Cost Estimates

Hydrological Findings

Station Drainage Area (km²) Mean Annual Runoff (mm)

Chacha River at Chacha 418 350

Muger River at Chancho 489 415

Beressa River at Debre Birhan 211 N/A

Key Challenges

Limited rainfall stations within project area

Incomplete rainfall records with poor overlap

No reliable correlations between streamflow and rainfall records

Synthetic streamflow sequences had to be derived for subbasins

Recommendations

The results are considered acceptable for prefeasibility level analysis, but the reference hydrology requires extensive review once actual streamflow observations at project sites become available.