h hl- H U DEMOCRATICREPUBLIC of Ethiopia Ml SIS m OF WATER RESOl R( ES
B \R()-AKORO RIVER BASIN
IN I EGR VII D DEVELOPMENT
M \ST I R PLAN STUDY
«
INAL REPORT
Volume V
PREFEASIBILITY STUDIES
May IW7
Mm YmL
VUHONSILTANTSLTD
UKFEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA MINISTRY OF WATER RESOURCES
BARO-AKOBO RIVER BASIN INTEGRATED DEVELOPMENT 
MASTER PLAN STUDY
VOLUME V
PREFEASIBILITY STUDIES
TAMS-L'LG B ar o- A kobo River Batin Iniegntcd Doelap men, Muter PlanINDEX OF VOLUMES AND ANNEXES
Vulum. I:.......-------------------------------- Executive Summary Volume resource Base and Development Options
Volume ID:........................................ -
FLAN DEVELOPMENT
Volume IV:.............................................. EROIECT AREA Maps Volume V------------ -------- ---------------- PrepeasiBILITV studies
annexes
1. WATER RESOURCES
Annex IA
Annex IB Hydrology
Annex IC Flood Studies
.Annex ID                 GroundWater Annex 1E
..Vinex if Sediment Studies
Climatology
Reservoir Operation Studies
Annex 1G                Water Resources Cost Estimating Annex IH  Irrigation Projects
Annex 11 Water Supply Projects
Annex IJ 
.......... Hydropower Projects
2         NATURAL RESOURCES
.Annex 2A Land Evaluation
Annex 2B Soils and Soil Conservation
Annex 2C
Annex 2D
Annex 2E Forestry Annex 2F Wildlife Annex 2G Tourism Annex 2H
Annex 21 Agriculture
Geology
Mineral Resources
..... Apiculture
Annex 2J ..................... ....................... Renewable Energy
Annex 2K  Fisheries
Annex 2L Livestock
3. SOCIO-ECONOMICS
Annex 3 A Population Aspects
Annex 3B ...................................... Socio-Ethnic Groups Analysis
Annex 3C
Economic Infrastructures
Annex 3DSocial Infrastructures
Annex 3E
Economic and Financial Analysis
Annex 3F Institutional Support
Annex 4
Environment
TAMS-ULG Barn-Akobo River Basin Integrated Development Master PlanPREFEASIBILm STUDIES
VOLUME V
VOLUME V
PREFEASIBILITY STUDIES
TAMS-ULG Baro-Aknho River Baiin Integrated Development Master PlanJPREFEASIBILm STUDIES
VOLUME V
CONTENTS
1.    background................................
1 I Master Plan Studies .............. -.....
12   Selection of Candidate Projects
13    Study Limitations
2.  GEBA HYDROELECTRIC PROJECT
2 I Introduction
...........
2.1 I Project Concept......................................
2.1.2    Project Area........................................
2.1.3    Power Planning...................................
2 2 Basic Data ........... ■■
2-2./ Topography.............................................
2.2.2    Hydrology............ ...............................
2.2.3    Site Geology.......................................
2.3   Project Development
2.3.1    Project Options...............................................
2.3.2    Reservoir    Operation    Studies....................
2.3.3    Access and Transmission Lines................
2.3.1    Project Layout ...............................................
2.3.5   Project Selection and Optimisation................
2.4  Environmental Assessment..............
■
-
e■ bi
2.5   The Recommended Project.............. 2.5.1    Project Description.................... 2.5.2    Quantity and Cost Estimate.. 2.5  .3 Implementation Schedule.........
2 6 Economic Appraisal ......... ........ ....
• +*
1 1
2
3 ..4
4
4 4 4
5 5 5 7
.7
.... 7 .... 8 ...10
...10 ....11
. . 14 ....20
...20
3.  GUMERO HYDROELECTRIC PROJECT.........
3.1    Introduction..............
.......... 21
........ 23
........23
....25
3.1        I Project Concept.................. ............. .......................................................................... 2->
3.1.2    Project Area.............. ..................................................................... ................................ 25
3.1.3 Power Planning.  .................................... . ..................................................................... .25
3  2 Basic Data ........................ ...................... ........................ .................... ........... .................. 26
3.2.1    Topography........................................................
3.2.2    Hydrology............... . ..........................................
3.2.3    Site Geology..................................... ................. 3.3   Project Development
3.3.7 Project Options............................................
3.3.2    Reservoir Operation Studies.............................
3.3  3 Access and Transmission Lines........................
3.3.4    Project Layout ... ..............................................
3.3.5    Project Selection and Optimisation...................
3.4   Environmental Assessment................... ...................
3 5 The Recommended Project.........................................
3.5  / Project Description.............................................. 3.5.2    Ouantin and Cost Estimate ........................
.26
.26
.27
28
.28
...30 ...31 ...31
. 34
42
TAMS-ULG Ban>-AkolMi River Basin Integrated Development Matter PlanPRE FEASIBILITY STUDIES
VOLUME V
TABLES
Table 2.1 Average Monthly Flows al Geba Dam (tn’/$) ............................................................................6
Table 2 2 Flood Frequency Analysis at Geba Dam.................................. ... 6
Table 2.3     Probable Maximum Precipitation ......................................................................................... 6
Table 2.4 Geba Reservoir Firm Flow (mJ,s) ............................ ............................................... ................. 8
Table 2.5        Monthly Flows at Geba Dam (mVs)............................................................. .................. 9
Table 2.6        Geba Hydroelectric Project - Annual Firm Energy (GWh).......................................... 10
Table 2.7        Project Optimisation Reservoir and Power Plant Characteristics................................... II
Table 2.8       Project Optimization - Cost Estimates (USS ,000).........................................................13
Table 2.9       Project Optimisation - Internal Rate ofRetum............................................................... 1*1
Table 2.10     Unit Prices (January 1996) ....................... 22
Table 2.11     Geba Hydroelectric Project Cost Estimate (USS - January 1996)............................ 23
Table 3.1       Average Monthly Flows at Gumero Dam (m'/s)
26
Table 3,2       Flood Frequency .Analysis at Gumero Dam..........27
Table 3 3       Probable Maximum Precipitation ................ .......... ........................................................27
Table 3 4       Monthly Flows at Gumero Dam (m’/s)........................................................................... 29
Table 3 5       Gumero Reservoir Firm Flow (m7$).............................................................................. 30
Table 3 6       Gumero 1 lydroelectric Project - Annual Firm Energy (GWh)....................................... 30
Table 3 7      Project Optimisation Reservoir and Power Plant Characteristics..................
32
Table 3 8      Project Optimization - Cost Estimate (USS ,000).......................................................  33
Table 3.9      Project Optimisation - Internal Rate ofRetum
34
Table 3.10    Unit Prices (January 1996).........................................................................................   42
Table 3.11    Gumero Hydroelectric Project Cost Estimate (USS - January 1996).......................... 43
Table4.) Long-term Rainfall (mm)................................................................ ...... ......................... . 47
Table 4 2       Seasonal Rainfall Distribution..................................................................................... 4g
Table 4 3       Annual Rainfall Variation (mm)
................ 48
Table 4 4       Average Maximum and Minimum Temperatures      (°C)
49
Table 4 5 Average Wind Speed (m/s)........................................................ . .49
Table 4.6       Relative Humidity (%)...................................... ..................................... ......................50
Table 4.7       Hours of Sunshine Per Day.........................................................................................50
Table 4.8 Potential Evapotranspiration and Lake Evaporation (mm) ..................................... ........ . 50
Table 4.9       Mean. Monthly and Annual Flows............................................................................  51
Table 4.10     .Annual Flow'Variation..................................... .. ...... ,,.............................................  51
Table 4 11     Maximum Instantaneous Watei Level     Elevations (mas!)........................................ 52
Table 4.12     Itang Irrigation Project Soils Samples Laboratory Tests............................................. 55
Table 4 13     Diversified Cropping Pattern ...............................................................................       57
Table  4  14  Itang  Irrigation  Project  Irrigation  Water  Requirements  -  Typical  Cropping
Pattern (Diversified)................................. ....................... ....... ......... ..................................... 59
Table 4-15 Itang Irrigation Project For Sugar Cane - Diversified Rotation Mix (2)........................... 60
Table    4.16 Monthly Irrigation Requirements (m7s per 10,000 hectares)
61
Table    4 17 Unit Costs (January 1996)......................................................................................... 65
Table    4 18 Itang Irrigation Project Cost Estimate - US Dollars (Jan 1996)................................. 68
Table    4 19 Itang Irrigation Project Annual Costs - 1000 USS (Jan. 1996)
69
Tabic 4 20 Economic Return of Crop (Birr/ha).................. .............. .... ..................................... ..71
Tabic 4 21 Cropping Build-up (hectares)......................................................... . ............. ............... 71
Table 4 22 Benefit Build-up (million Birr). ...................... .......... .... ............................................ .72
TAMS-ULG H*ro-Akobo River Batin Integrated Development Master Pl*nPRE FEASIBILITY STUDIES
VOLUME V
J  J  J  Implementation  Schedule 3 6 Economic Appraisal
4. ITANG IRRIGATION PROJECT................
4  I Introduction ................................................. ...........
4.1.1    Project Area................. .................................
4.1.2    Institutional Setting........................................
4,2    Basic Data
4.2.1    Topography.................................. -...............
4.2 2 Climatic Data ..... ............................•..............
4.2.3    Hydrology............................................. ........
4.2.4    Sediment Data.. ....... . ..................................
4.25 Water Quality for Irrigation.................................
4.2.6    Land Resources.......................... ...................
4.2.7    Geology and Geotechnical............................
4 3 Project Development................................................
4.3, / Agriculture and Crapping Patterns....................
4 3 2 Irrigation Waler Requirements..........................
4.3.J Reservoir Operation Studies..................... ......
4.3.4    Irrigation Infrastructure.......................... .......
4.3.5    Estimates of Costs and Benefits.................. .
4 4 The Recommended Project.....................................
4.4.1    Project Description.................................
4.4.2    Cost Estimates..............................................
43
44
........ 45
.......... 45
46
46
......... 46
.........46
......... 51
......... 52
.........52
......... 53
......... 56
........ 56
......... 56
......... 58
......... 6!
..........61
.......... 64
........ 65
......... 65
......... 67
4.4.3    Implementation Schedule......... ................................ ....................................... ........... ..67
4.4.4    Economic Analysis..................................... ............... ................. . ........................... . 70
4 4.5 Environmental Assessment........................ ....... ....................... .......................................72
APPENDICES...............
FIGURES
Figure 1 1 Project Location Map
Figure 2-1 EELPA Peak Power Demand Forecast
Figure 2 2 Geba River at Geba-A Dam Site Yield Curve al 98% Reliability
Figure 2-3 Geba Reservoir Area-Capacity Curve
Figure 2.4 Geba Hydroelectric Project Construction Schedule
Figure 3-1 Baro-Akobo Basin Peak Power Demand Forecast
Figure  3.2  Gumero  River  at  Gumero  Dam  Site  Yield  Curve  at  98%  Reliability Figure 3-3 Gumero Reservoir Area-Capacity Curve
Figure 3 4 Gumero Hydroelectric Project Construction Schedule
Figure 3 5 Gumero Hydroelectric Project Implementation to Meet the Local Demand Figure 4 1 Gross Monthly Irrigation Water Requirements for Sugar Cane-Diversified
Cropping
Figure 4.2 Itang Reservoir Area-Capacity Curve Figure 4 3 Itang Irrigation Implementation Schedule
TAMS-ULG Baro-Akobo River Easin Integrated Development Master Plan
itPREFEASIBILITY STUDIES
VOLUME V
1.        BACKGROUND
LI Master Plan Studies
This  volume contains  the prefeasibility  reports  for three water resources  projects  which are components  of the Master Plan for Integrated Development of the Baro-Akobo River Basin. It is one of twelve regional Master Plans commissioned by the Government of Ethiopia io assess the development potential of water, natural and social resources of the country
The Water Resources Development Authority contracted this Master Plan study to the association of TAMS Consultants, Inc of New York and ULG Consultants of Warwick, U .K , in June 1995, the studies were initiated in July 1995 and were completed in November 1996
In accordance with the Terms of Reference for the Consultancy Services, the study shall include the following
A review of the existing database,
•    A portfolio of prioritised development projects,
•    A Master Plan for the integrated development of the Basin,
•     Information and data  required  for co-operative development undertakings with downstream countries and,
•    Prefeasibility level studies of selected high-priority water resources projects.
The planning and engineering studies performed during the elaboration of the Master Plan are essentially contained in Volumes 2 and 3 and in the Annexes Volume I contains the Executive
Summary, and the maps are presented in Volume 4. The major water resources projects are reviewed and evaluated in Annex 1H - Irrigation Projects and Annex IJ - Hydropower Projects
Three projects were selected for prefeasibility level studies (Figure 1.1). They are:
the Geba Hydroelectric project on the Geba River, located approximately 60 km east of Gore in the upper reaches of the Baro basin,
die Gumero Hydroelectric project on the Gumero river, located 20 Ian west of Meru, also in the Baro basin and,
the Itang Irrigation project with a dam impounding the Baro river 30 km downstream of Gambela and an irrigation area on (he right bank in the vicinity of Itang.
I A MS- L' LG Bare-A kobo River Buin Integrated Development Muter Plan
I
Chapter IGEBA DAU
MINISTRY OF WATER RESOURCES ADO«S ABABA ETHIOPIA
KtM-MOW MASTER PLAN PREFEAS1BIUTY STUDIES
BASIN MAPPRE FEASIBILITY STUDIES
VOLUME V
] .2 Selection of Candidate Projects
The Master Plan studies have included the appraisal of a number of water resources projects m ^B^Akobobasut Overall. 22 dam projects, 19 hydropower plant projects  and 14 .mgatton schemes have been reviewed
With regard to the hydropower potential of the basin, it is clear that the large and medium-size projectsare loo large for the anticipated growth of electricity  demand within the basin which is expected to reach 61 MW in year 2020 These projects must be justified within the context ot the Interconnected System (ICS) The Master Plan studies, detailed in Annex  1J, have identified several projects with attractive economic returns
In the range of medium to large-scale projects, the Bare and Geba projects have the potential for about 210 MW and 170 MW, respectively, al costs  lower than the projects  identified in the EELPA expansion plan Both projects  consist of a storage dam for regulating the river flows combined with two downstream hydropower plants at the location of steep reaches ot the river
Both  projects,  therefore,  present  the  possibility  of  staged  development  if  the  economic  and/or financial conditions dictate such an approach In this case, the Geba project would be preferable since the two stages of development (100 MW and 70 MW) would be in the medium-size range
With the Bare scheme there is a large disparity' between the size of projects, with the initial single stage being either a 40 MW or a 170 MW power plant, the latter being already  a large-size project Furthermore it appears  from the only  available topographic  map, dated 1977 at a I 50,000 scale, that the reservoir area of the Bare scheme is much more populated than that of Geba, and therefore would require the relocation of a larger number of people As  a consequence, the Geba hydroelectric project was selected for prefeasibility level sludies.
As indicated above, at the present the Baro-Akobo basin has a limited demand for electric power, growing from an estimated 21 MW in year 2000 to 61 MW in year 2020 (a growth rate of 5,5% per year) The Master Plan sludies (Annex 1 J) have identified several small-size projects that would be suitable to meet that demand Among them it appears  that the best-suited scheme would be a staged development of the Gumero project. The Gumero project, similarly  to the Geba arid Bare, consists of a regulating reservoir in the upper reach of the Gumero River and three power diversions in cascade downstream of the dam taking advantage of the sleep profile of the river The Gumero project s  ultimate development would be approximately  50 MW, at three power plants  of 12 MW. 18 MW and 20 MW respectively  If the decision is  taken to implement this scheme, and to follow the demand for power in the basin, the first power plant could come on line by year 2005, the second (18 MW) in year 2012 and (he third (20 MW) in year 2018 The project cost appears  io be significantly  lower than the alternate sources  of electric power in the basin which are mainly isolated diesel plants
With regard to the irrigation project, the Master Plan studies indicated that completion of the ongoing Alwero Abobo dam project should be given first priority Thcieafler three other projects were selected tor consideration in the Master Planning These are the hang Irrigation project on the right bank ot the Baro using gravity feed from hang Dam, the upstream .Alwero project fed by gravity from Dumbong dam, and the Gilo-2 right bank project fed by gravity- from Gilo2 dam
The hang project stands out as being the most economically viable.
TAMS-ITLG Barn-Aknbn River Baiia Integrated Development Muter Plan
Chapter 1PREFEASIBILITY STUDIES
VOLUME V
1.3 Study Limitations
When the three projects for prefeasibility lev el studies were identified in the course of
r
the Master
Plan studies, it was clear that additional site data would be required to develop the projects to the prefeasibility  level In particular for the Gumero and Geba hydroelectric  projects, the only topographic  data available were the 1:50,000 scale maps, dated 1977 To meet the data requirements  the following fieldwork  was  requested at each project area from WRDA, as piovided for under the consulting services agreement
a map of the reservoir areas at a 1 10,000 scale with 5-metre contour intervals.
a topographic map at a 1 2,000 scale with 2-metre contour interv als at the location of all the structures, and
cross sections along the alignments of power canals at an approximate rate of three sections per kilometre
It was also recommended that provision be made to perform a number of test pits, preferably one at each structure location These test pits were to be performed under the supervision of a geologist
Unfortunately, for vanous reasons WRDA were not in a position to undertake the field work and the Consultants were instructed to complete the prefeasibility studies using the available data, i e the 1 50.000 topographic maps
The studies performed therefore in the course of these prefeasibilitv level evaluations have a number of uncertainties, mainh related to the deficiencies of some of the basic data that would be expected for a study at that level The data deficiencies will have to be corrected prior to initiating the next step towards the implementation of the projects, i.e, before commencing
feasibility studies 
The lack of data concerns principally the absence of adequate topography for the hydro i projects and of basic geology and geotechnical information for the power and irrigate Dro °
For each of these projects, the reservoir ability to regulate the river flow s on an inter- $ basis is a major factor in the viability of the project Similarly, the detail of the topocranhv dam sites at the location of the major structures and along the long power canal routes for * Geba and Gumero Projects, will need to be improved significantly for an adequate asses  **
®
fC
the civil work required and to better define the quantity and cost estimates 
mci11
TAMS-UI.G Baro-Akobo River Batin Integrated Development Master PlanPREFEASIBILITY STUDIES
VOLUME V
2, 
GE BA HYDROELECTRIC PROJECT
2.1 Int
roduction
2.1.1
Project Concept
In  the
review  of  the  hydropower
resources  of  the  Baro-Akobo  basin
(see
.Annex  !  J),  several
hydropower projects have been identified that have the potential of providing low cost energy and power to the interconnected system (ICS). The most promising of these is the Geba hydroelectric project which is located in the upper reaches of the Bare River
The Geba project is inherently attractive because of two main factors, high river flows (this area has the highest rainfall in Ethiopia) and high head potential created by the natural drop in over bed levels in the steep upper reaches of the Baro River
The project concept is to create a reservoir at the head of the steep reaches of the river to regulate the natural river flows, and to develop hydropower by bypassing the particularly steep stretches of the river using systems of canals, surface penstocks and surface powerhouse. This concept is illustrated in Drawing No.GE-I (Appendix  2-1) which shows  Geba dam and two downstream diversion systems, which can develop about 110 MW and 70 MW respectively.
At these installed capacities the Geba project fits wdl with Ethiopia’s present policy in the power sector of developing medium-scale hydropower. The project will also facilitate irrigation development downstream on the Baro River by increasing the firm flow of the river
2.1.2    Project Area
The project is located on the Geba River about 120 km upstream of its junction with the Birbir
River The storage dam site is 60 km east of Gore and 35 km west of Bedele At its closest
point, the Metu-Bedeie road is 18 km north of the site The area is forested with gentle relief and rolling country According to the only information available, the 1977 1 50.000 maps, the
reservoir area is unpopulated and there were no roads Land slopes at the site range from 2 to 40%, while the river gradient is about 0.3% At the diversion sites the cross slopes are 70% or even steeper while the river slope increases to 8 and 3% at the first and second diversions respectively The Geba River rises in mountains to the south of the site at about elevation 2500.
At the site itself the river is at elevation 2130, falling to 1840 and 1500 at the powerhouses for Diversion 1 and Diversion 2 respectively.
2.1.3    Power Planning
At present the existing countrywide generating capacity of approximately 400 MW serves a total population of 57 million people. Of this total capacity, the installed capacity connected to the Inter Connected System (ICS), which does not serve the whole country, is 3S5 MW. The
TAMS-ULG B*ro-Akobo River Basin Integrated Development Mailer Plan
4
Chapter 2PEAK POWER DEMAND (MW)
xn
1
EELPA PEAK POWER
DEMAND FORECAST
Figure 2-1Firm Flow (m3/s)
Geba River at Geba-A Dam Site
Yield Curve at 98% Reliability
Figure 2.2Elevation in matars
Area In km2
Legend
Initial
Geba Reservoir
After Segmentation ?
Area-Capacity Curve
Figure 2-3PRE FEA
SIBILITY' STUDIES
VOLUME
 V
population
is    estimated    to    be    growing
at
an
annual
r
ate
of
3/.    In
recent    yearsjmcc 
the
implementat
ion    of    a    comprehensive    prog
ram
of
economic 
ref
orm
f
ollowing
the    drought   and
hzr.il
war  of  the
1980s.  the  economy  has  recu
perate
d
and  is  no
w
g
rowin
g
at  an
annual  rate  of  7’
»a
year
An ambitious program of power generation development, both hydropower and thermal, is 
planned to meet the growth of demand, taken by EELPA to be at an annual rate of 10% a year
It is estimated that approximately 1800 MW of generating capacity needs to be commissioned
over the next 20 years to satisfy the growth in demand, as is illustrated in Fjgure 2-1
The hydroelectric  power studies  performed for the purpose of this  Master Plan (Annex  1 J) have shown that the Geba Hydroelectric  Project could be a candidate to be integrated mto the ICS as eariv as 2004
2.2      Basic Data
2.2.1 Topography
As noted above, the only  survey  data available is  from 1977. The maps  were compiled from aerial photography  dated November 1973-January  1974 and November 1975-January  1976 by  Hunting Survey  Ltd with field completion by  Ethiopian ^Mapping Agency  in December 1977 The scale of the maps is 1 50,000 and the contour interval 20 metres
2-Z2 Hydrology
The Geba project is  on lhe Geba River and has  a catchment area of 1,086 km1 at the location of the storage dam The hydrometric  network  of the Bare River basin, which includes  the Geba River, consists  of a total of 10 stations  and only  two stations  having more than twelve years  of records. These are on the Baro River at Gambela and on the Sor River at Metu where lhe
catchment areas are 23,461 km  and 1,648 km
2
2 respectively
The   river   flow   at   the   location   of   the   dam   was   estimated   in   accordance   with   the   methodology developed in Annex i B - Hydrology of the Master Plan. The methodology used consisted in:
infilling gap by linear repression,
correlation  between  monthly  flows  and  rainfall  for  a  set  of  representative  stations  nf.tr  the catchment, and
stochastic modelling to generate long-term (74 years) monthly flow series Table 2 I shows the long-term monthly average at the dam site.
TAMS-LLC Bero-Akobo River Bum Integrated Development Muter Plan
5
Chipter 2volume\
PREFLASIBILITY STI DIES
TlM.U
January Fcbruan March
I Apnl
Ms'
June
The   mean variation
72 
40
25
10 6
282
July 
-
August^ _
1  September
October______
3 9 
November December
69 8 95 7 
110.0 65 9
annual   discharge   is   35.7   m*/s   or   1.127   mcm   with   a   strongly   pronounced   seasonal 91% of the runoff occurs in the 6 wet months from June to November
Using the available flow records  in the basin, a flood frequency  analysts  was  performed to determine flow for different return periods  at the Geba site The results  of this  analy  sis. (Annex 
IC). which are shown on Table 2 2. were based on the Sor River gauging station.
Table 2.2 Flood Frequency Analysis al Geba Dam
Return Period
J
Discharge (m /s)
10 vear
292
100 vear
462
500 vear
631
For the meteorological and rainfall gauging stations  located in the vicinity  of the basin, a statistical analysis  of the maximum daily  precipitation was  performed. Applying the Hershfield methodology, as  indicated in Annex  IC - Flood Studies  of the Master Plan, the precipitation data were used to estimate the 24-hour Probable Maximum Precipitation (PMP) at these various rainfall stations. The results of this analysis are shown on Table 2-3.
Table 2.3 Probable Maximum Precipitation
Starions
24-Hour PMP (mm)
i
Chora
------ J
377
-----------------------------
Gore
400
Mefu
336
----- —--------- -- -------
Hurumu______________________________________ -------------------------------------- - —— -
Based on this analysis the 24-hour point PMP for the Geba catchment area was 400 mm For the purpose of this prefeasibility study, a simplified HEC-] mode]
to be
to   estimate   the   inflow   hydrograph   of   the   spillway   design   flood   The   peak   discha/^   ^CVe'°ped
to be J. 140 m3/$.
8c 15 Miniated
There  is  no  available  data  on  suspended  sediment  in  (he  vicinity  of  the  site  A  dJSc sedimentation estimate for all reviewed reservoirs is presented in Annex IF to the xJ,On the
TAMS-ULG Baro-Akobo River Banin Integrated Development Master Plan
6PREFEASIBirm STUDIES
VOLUME V
Report   For   the   purpose   of   planning,   the   reservoir   operation   studies   considered   the   accumulation of  sediment  in  the  reservoir  at  an  annual  rate  of  IJ20.000  m1
113 Site Geology
The damsite is  located on Basalt The ARDCO-GEOSERV geological sketch map of the area shows  Alluvium over Mekonnen Basalt over hornblende and biotite gneisses  At the dam site, alluvium overlies  the basalt foundation The site is  located right at the comer of available aerial photos, strip 16, photo 1323, and is  not stereoscopic  The whole area is  forested with gentle relief and rollma country  Rock  is  likely  to be far below the surface, although downstream of the dam site the AG report indicates  that gorges  cut into basement hornblende and biotite gneisses 
The   area   is   dominated   by   N-S,   NE-SW   and   E-W   faults   From   the   aerial   photo   there   is   no indication  oflarge  areas  of  outcropping  rock,  but  possible  basalt  outcrops  ore  present  to  the  north of  the  site  in  the  Kombo  area  which  might  provide  a  rockfill  quarry  The  clay  on  the  hill  slopes is  reputedly  suitable  for  impervious  fill.  Due  to  the  lack  of  rock  an  earthfill  dam  is  recommended The  north-south  fault  near  the  dam  axis  to  the  east  shown  on  the  sketch  map  must  be  investigated
Sand and gravel is  found in the Geba flood plains  A diversion tunnel should be easily  constructed
in  basalt  with  support  of  shotcrete,  wire  mesh  and  rockbolts.  The  canals  for  diversions  1  and  2
are  likely  to  be  partly  in  bnsalt  and  partly  in  hornblende  and  biotite  gneisses  The  powerhouses  arc more likely to be founded on gneisses
2.3      Project Development
2.3.1 Project Options
Based on aerial photography  interpretations, there do not seem to be any  nearby  quarry  sites  for rockfill Consequently, an earthfill dam has  been selected for the prefeasibility  design. However, if a field survey, or even ground reconnaissance with auguring were performed, it could indicate that a rockfill should be considered Under such conditions  a concrete-faced rockfill might also be an attractive alternative, since, with a maximum height of 45 metres, it is  within the range where concrete-faced rockfills are economical
Aerial photographic interpretation indicates the existence of a north-south fault on the right abutment at the site Consequently the spillway has been positioned on the left abutment, where the topography requires a long, concrete-paved chute leading to a stilling basin at the edge of the river some distance downstream If a field survey were to indicate that this fault would present
no hazard to a spillway constructed on the right bank, this would result in a much shorter chute this option should be considered after further investigation.
With a 275-metre head available at the end of a 3,500-met re long canal, and considering a drainage area of ov er 1,100 km*, a first-stage run-of-river development at the Geba 1 Diversion site might be considered With an 80% probability flow of only 3.5 m /s, it is not considered economically feasible, but depending on other development options in the basin, it could be worth considering
J
TAMS-ULG BaroAkoba River Baiin Lb Iff rated Dt^ckpraeof Mailer Plan
7
Chapter 2PREFEASIBILm STUDIES
As previously noted, the only topography available is at a scale of 1.50,000 wj h 20.^
t
contours From this topography, the site selected is appropnate. and the quannty and
estimates ha« been prepared accordingly W ben more detailed and larger scale, topog^
becomes available, it may well be that a more economical site can be found, or in any event,
a more economical arrangement of structures and layout can be made
23 2 Rocrwir Operation Studies
Asintalri (he -ese™, will regulae (he river flow (o be used at two downs.™, hydroelectric  power plants  The HEC-5 computer model was  used to estimate the yield, or firm flow that can be guaranteed bv operating the reservoir so as to release a constant flow For the purpose of this study, the yield was defined as the constant monthly discharge for which the long term average deficit is  2% of the yield (98% reliability) The HEC-5 model performs  a monthly routing of the 74-year long flow time series at the dam site Figure 2 2 shows the yield in m’/s of the Geba River at the dam location as a function of the reservoir active storage This curve w as used to estimate the yield of the reservoir for a set of maximum reservoir operating level
The active storage of each reservoir was determined as the storage above El 2145 taking into account the accumulation of 50 years  of sediment The area-capacity  curve of the sedimented reservoir was  determined by  the use of the methodology  developed by  Borland, Miller and Moody Table 2 4 shows the firm flow at 98% reliability for the four reservoir levels selected for optimisation of the Geba project Figure 2 3 shows the area capacity curves resulting from this computation for the reservoir with a maximum operating level at El 2,170. Table 2 5 shows the 74-year long flow time series used with the HEC-5 program
Table 2.4 Geba Reservoir Firm Flow (m /j)
3
Maximum Reservoir Level   Active Storage (mcm)
El 2160
290
rjrr------------------- - -------------------
J
Firm Flow(m /s>
5ol *------------------- 1-------------------
El 2165
502
El 2170                                         792
El 2175
1.183
27.2---------------------- —--------- ---
TFT ----------------
32 8         - ------------ ---------------
For each of these selected reservoir levels, the firm enerev
_          _______________ ___________ a: B««waicu annually by the project was determined assu’mhg an overall efficiency of 85%. and waterway head losses of 6% The gross heads  developed  at  the  first  and  second  power  diversfons  are  275  metre  and  175  metre respectively Table 2 6 shows the annual firm energy generated by the project for each of the selected maximum operating pool
TAMS-ULG Ba ro-A kobo River Bai in Integrated I>e*clopment Mailer Plan
8Monthly Ftowi at Obi OwnFRKFEASIBIIJTY STI DIES
VOLUME V
Tibk 16 Griw Hydroelectric Project - Annual Firm Energy (GWh)
Maiimum Rrvcnoir Levri
Dhenion No. 1 Firm
Energy (GWhSr)
Diversion No. 2 Firm
Energy (GWh/yr)
EK 160
386
245
El 2165                                                                  514                                                      327
' El 21*0                                                                  588                                                      374
El 2175                                                                  620                                                     394
2J.J 4cccm and Transmission Lincs
previously   noted,   the   main   storage   dam   at   Geba   is   located   18   km   south   of   the   Metu-Bedele road  which  is  also  the  main  access  road  from  Addis  Ababa  At  the  present  time,  there  is  no  road access   to  the   site,  or  to  either  of  the  diversions  However,  the  Geba  2  Diversion  Powerhouse  is less  than  I;  km  from  the  road  Access  to  the  sites  farther  south  will  require  pioneering  road  work, with  a  total  route  mileage  probably  wdl  in  excess  of  18  km  Eventually,  the  power  canals  for  the two  diversions  (a  total  of  9.5  km)  could  be  pan  of  the  permanent  access,  but  whether  these  could be constructed as pan of the construction access must await a more detailed route survey
At the present time, the closest point on the ICS to the Geba Project is  at Jimma, 140 road kilometres  on the Metu-Bcdele-Jimma highway, or 100 kilometres  overland However, it is  noted that there are plans  to extend the ICS to Bedcle, only  35 km away  by  year 2000 In the other direction, the existing Sor-Metu-Gore-Gambeia 66 kV line is  60 km away  For the size of the project considered at Geba, i c  , a combined capacity  in excess  of 150 MW, the power plants  will serve the ICS with the bulk  of the load being around Addis  Ababa Therefore they  should be connected with a double circuit 230 kV system at Gilgel Gibe, which is  presently  180 km from the power plants
2.3.4 Projeef Layout
Based on the available topography, the dam site selected appears  to be the only  one favourable and feasible It is  at the downstream end of a wide, flat and frequently  marshy  flood plain, where a dam of modest height can develop substantial storage for regulation of the Geba River flows 
As  of  the  1977  survey,  (he  Latest  available,  there  was  no  development  within  the  reservoir  area. So  relocation  costs  should  be  minimal  By  the  same  token,  access  will  be  difficult,  given  (hat  there are   virtually   no   roads   in   the   area,   and   a   new   access   road   will   need   to   be   built,   both   for construction and operation of the project.
At  the  dam  site,  a  fault  inferred  from  aerial  photography  precludes  location  of  the  spillway  on  the right   abutment,   a   location   which   otherwise,   topographically,   would   be   more   favourable   as   the required   spillway   chute   would   be   much   shorter  With   the   spillway   located   on  the   left   abutment, it  appeared  to  be  more  appropriate  to  pul  the  diversion  tunnels  on  the  right  abutment.  They  will cross   the   inferred   fault   near   the   downstream   portal,   but   at   depth   An   allowance   for   additional tunnel  support  at  this  location  has  been  made  in  the  cost  estimate.  One  of  the  tunnels  will  be  used for  making  releases  to  the  power  projects  downstream,  and  since  a  multilevel  outlet  is  required for  environmental  reasons,  locating  the  tunnels  on  the  right  bank  avoids  interference  between  the outlet tower and the spillway intake.
TAMS-ULG Btro-Akoho Rher Buis Integrated Doekipmcnt Muter Plan
10
Chapter 2PREFEASIBItm STUDIES
VOLUME V
The mo power diversions  arc  located on the 'eft bank, at the heads  of falls, where contour canals of minimum length can be constructed to feed very  steeply  stoping penstocks  leadh^ to the pow erhouses  In the case of Diversion No I. the canal could be extended another 15 DO metres, to 6000 total, to pick  up another 120 metres  of head This  would, however, require a much longer penstock with possible associated problems of regulation
2.3.5 Project Selection and Optimisation
For the purpose of selecting the size of (he project to be developed al the Gcba site, cost estimates for four levels  of reserv  oir were prepared For the purpose of this  prefeasibility  study, the project- installed capacity  has  been selected to provide a project plant factor of approximately  60% This plant factor will require optimisation at the feasibility  or design stage This  plant factor is  close to the system load factor which is adequate to provide a fair evaluation of the project
The two hydropower diversions  downstream of (he storage dam, are essentially  njn-of-river projects  utilising the resmlated releases  from the reservoir As  a consequence, for each reservoir level selected, the installed capacity is determined by the firm yield of the reservoir al that level
Since the hydroelectric  benefits  of the project do not depend on the head created by  the storage dam, the minimum reservoir operating level is  selected as  the minimum technical and environmentally  feasible, taking into account the estimated sediment deposit in the reservoir over the life of the project On that basis  the minimum reserv  oir level selected is  at El 2145 Table 2 7 shows the mam characteristics of the projects selected for optimisation
Table 2.7 Project Optimisation Reservoir and Power Plant Characteristics
Minimum Reservoir Level
2145
2145                  2145                   2145
Maximum Reservoir Level
2160
2165
2170                   2175
Ave Regulated Discharge (m'/i)
20 4
27.2
31 0                    32.8
Max. Power Discharge im /si
34 0
45 3                    51.7
54.7
Diversion No lHeadt'mj
275                     275                     275
275
Diversion No 1 Capacity (MW)
73
98                       112
118
Diversion No. 2 Head (ml
175
175                     175
175
Diversion No 2 Capacity (MW)
47
62                       71
75
The cost estimate for each of these projects  was  prepared in accordance with the methodology established in Annex  IG. Water Resources  Cost Estimating of the Master Plan A summary  of the major cost items is shown on Table 2.8
The project size selection was  made on the basis  of the highest internal rate of return (TRR), taking into account the feasibility  study, design and administration costs, the cost of construction allocated over a period of four years, the cost of operation and maintenance and the revenue from the sales  ot firm energy  At the feasibility  level the optimisation will be done on the basis  of the incremental IRR.
TAMS-ULG Biro-Akobo River Buin Integrated Development Muter Plan
11
Chapter 2PREFEASIBIITTY STI DIES
VOLUME V
Ai   shown   on   Tabic   2   S,   the   com    for   engineering   and   administration   of   the   project   have   been estimated at 10** of the total construction cost
The   cost   of   operation   and   maintenance   over   the   50-year   life   of   the   projeci   were   estimated   as follows
0 5% for civil works
2 5% for electromechanical equipment
1 0% for transmission lines
Revenues  from  the  sales  of  firm  energy  were  estimated  at  the  rate  of  USS  0  06/k  Wh  (January 1996)
TA MS-L'US B-ro-AknU River Buin Intetjr.ted Dcvelopmenl Muter Plan
Chapter 2
12Ma* Nor Res i^vel
Table Z8
project Optimization * Cost Estimates (USS ,000)
Price Level : January 1996
EL 2,165         EL 2x170
EL 2.160
EL 2,175 1<1«®<Wa!U¥V*J
Div.  No.1  Inst  Cap  _ Div No 2 Inst Cap
73 MW
47 MW
98 MW
62 MW
152 MW
71 MW
75 MW
.
Dam & App. Works____________ _
ra
12.219
JL    I
3 569
4 194
4,956
Preliminary                        ------ ----------— Main Dam                         - ------------ -----
15 602
4 OatWmi
19 772
2 600
24 861
2 60C
Access Road
2.600
2 421
.r
2421
2 421
2 421 ■
2 918
2 918
2 918
2,918
i riw l           Outlet
250
250
250
250
-------------- _------------------------ sUbioai             23,469           27.WO           32,1*4
Power Plant 8 Conveyance
Uivuriaiun iw. i
Preliminary
6 186
7.S97,,
8 857
9.272
Ah*j»c$ iRnad
345
348
348
348
Power Intake
0
0
0
0
Power Canal
7,476
7476
7,476
7.478
Power Tunnel
0
0
0
0
Surge Shaft
0
0
0
0
Pressure Shaft
0
0
0
0
Penstock & Manifold
3485
4843
5 300
5 608
Powerhouse 5 Equipment
29 930
40,180
45 920
48 380
»*
»■
No
Preliminary
4.467
5.569
6 229
6 522
Access Road
60
80
BON
80
Power Intake
0
0
0
0
Power Canal
8 729
6 729
6729
6729
Power Tunnel
0
o
0
0
Surge Shat!
0
0
o
0
Pressure Shah
0
0
0
0
Penstock & Manifold
1.118
1,490
1.700
1.798
Powerhouse A Equipment
21 855
28.830
33,015
34.B75
Subtotal
34,249
42,698
47.752
50,004
Transmission System
Preliminary
5 265
5,307
5331
5 342
Switchyard Div. Not
1006
1,163
1 250
1.288
Switchyard Div. No2
842
987
1.042
LOTS
Transmission Line
33.250
33.250
33,250
33.250
Subtotal 40.363
40,687              40,873               40.954
[Reservoir Area Clearing
2,160
3.054
3,948
[Population Relocation
5,506
700
700
700
700
Subtotal
148.366
175 043
Physical Contingencies (20%)
193,328
206758
29 673
35 009
Engineering & Administration (10%)
38 666
4l 252
17,804
21 005
23499
r
24 751VOLUME V
PHI FF \S1HI1 ITS STI DIFS
BauxJ    on    the*    assumptions.,hc      ,RR      of      thc      fpur      *leC,d      *hCniCS      WCTC      COmpU'Cd      35      Sh°U71      °n
Table 2 9
Table 2.”
Project Optimisation - Internal Rate of Return
Maximum Reservoir Level Dncnxm No 1 Ins: Cap DntnxxiNo 2 Ins Cap
El 2160             El 2165              El 2170               El 2175 73                     98                    112                  118
47
62
71                    75
Total Construction Cost (U SS mil)               195 8                231 9                 255 2               272 3
Annual O £ M Cost (USS mil)                           2 80                  3 49                  3 91                 4 12
Firm Energy (GWhyr)                                  631                   841                    962              1.014
Xnmul Revenue (USS mil)                             37 86                50 46                57 72               60 84
IRR (%l
14 4%               16 0%               16 4%              16 3%
On that basis, thc Geba project with a maximum operating pool at El 2,170 was selected The number of units and thc unit size were selected based on the fact that, al the present, the largest unit sue tn the ICS is  approximately  30 MW and that thc  total installed capacity  of the Geba project would represent a 48% increase of the existing installed capacity  of Ethiopia If the project wee to come on line in year 2004, it appears appropriate to select unit size of about thc same size Hence, the power plant at Diversion No 1 will house four 28-MW units  and at Diversion No 2. three 24-MW units  The installed capacity  of the project will be 112 NW for Diversion No 1 and 72 NW for Diversion No 2
2.4     Environmental Assessment
The Geba dam site is located in the Dlubabor region near the eastern edge of the Master Plan area, on the Geba River, 120 km upstream of its  confluence with the Birbir River Its  geology  is composed of faulted basalt in combination with other rocks overlain by alluvium Its landscape is rolling, its vegetation forest
The dam would be 45 metres high and 475 metres long It would discharge water into the Geba River, where two m-line diversions, power canals, and powerhouses  would use its  flow to generate electncity The first diversion is 4 km downstream of the dam. the second 17 km The respective lengths of their power canals are 3 5 and 6 km
Geba reservoir would cover an area of 90 km , its watershed covers 1,086 km . Mean annual flow at Geba dam site is estimated to be 35.9 m’/s or 11,300 MCM per annum Its normal maximum operating level would be 2,170 m, its minimum 2,145 m, a difference of 25 m Maximum capacity of the reservoir, including dead and live storage, is 865 MCM The average residence time of water, computed by dividing storage by annual flow, is 0 91 month on the average, the reservoir would replace its waler about 13 times per year
Positive impacts
This section discusses the potential non-hydroelectric benefits of the project Potential positive impacts include flood control, reservoir fishenes. fuelwood and recession agriculture and grazing
2
1
TAMS-ULG Baro-Akobo Rlwr Bull Integnled Development Muter
Chapter 2PREFEASTBI
UTY STUDIES
VOLUM
E V
Flood   control
A
Hood   surcharge
volum
e
of   300
mill
ion   cubi
c 
metre*
fmcroi
is 
provided
F!<xxi
attenuation    will
undoubtedly   occur
as 
a
result
of
normal
res
ervoir
operatio
ns 
However
Hood
control  is  not  the  primary  purpose  of  the  reservoir,  and  based  on  the  review  of  the  1  50,000  scale map, it appears there is practically no settlement on the Gumero and the Ofa rivers
Reservoir fisheries Neither the study  by  Selkhorpromexport nor ARDCO-GEOSER^ provides fisheries  estimates  for impoundments  in the upper basin Selkhozpromexport H93S> estimated that the Abobo reservoir in the lower basin could produce an annual catch ot 100 t tor its 2 2IQ hectares  reservoir This  result cannot be extrapolated to upland rescr.ous, however, without further study
Fuetwood Among the mitigations  recommended by  this  assessment is  the total clearance of biodegradable material from the reservoir area The woody  biomass  of the dam and reservoir ate
has not been surveyed other than in the context of the 1995 3 <xxA
Survuy by Tnenau.v
Using his  results, the reservoir lies  in an area whose potential dry' woody  biomass  lies  between
30 and 50 uha For rhe area of the Geba reservoir (66 km ), this  translates  into a potential
2
fuclwood supply  of between tonnes  At 5 Birr per 20 kg bundle of file I wood, its  gross  resale value, exclusive of the cost of collection and preparation, is  between 49 5 and 82 5 million birr (USS 7 9 and IJ 2 million)
Recession apneuifure and mmnv The reservoir offers the potential for recession grazing and
agriculture during the dry season Poorly drained areas have been traditionally used for dryland
grazing in much of Ethiopia, recession agriculture in the upper basin is much less well-known
Given the small difference between minimum and maximum reservoir operating levels, shorelines 
are likely to be broad and undulating, and grazing production could flourish as, indeed, it does in
natural basins and many reservoirs throughout the country It is a resource suitable for control
and regulation through a permit system, which could be a source of revenue
Negative environmenfa/ impacts and their mitigations
Large dam projects  cause irreversible environmental changes  over a wide geographic  area and thus  have the potential for significant impacts  The area of influence of a dam project extends from the upper limits  of the catchment to far downstream While there are direct environmental impacts  associated with the construction of the dam, the greatest impacts  result from the impoundment oi water and alteration of water flow downstream. These effects  have direct impacts  on soils, vegetation, wildlife and wildlands, fisheries, climate, and human population in the area The dam s  indirect effects  include those associated with the buildme and maintenance of the dam, the operation of the reservoir and the development of agricultural industrial, or municipal activities made possible by the dam
The    negative    environmental    impacts   that    result   from   dams   and   reservoirs   could   include   the following
- Construction camp,
•     Roads, and
Dam and appurtenant works. Dislocation of people,
*     Loss of land
TA.MS-ULC BaroAkobo Rher Biiin taief rated Development Muter Plan
IS
Chapter 2VOLUME V
PREFEASJBILITV STUDIES
. Loss of historic or other features.
•    Loss of wildlife habitat,
•    Proliferation of aquatic weeds,
•    Deterioration of water quality.
•    Reservoir sedimentation,
•    Riverine fisheries,
•    Water-related diseases,
•    Conflicting demands for water, and
•    Increased land pressure
Consmtciion camp Construction camps usually comprise quarters for between 200 and 600 men, and contain showers, cooking facilities, toilets, generators, fuel dumps, cement machines, parking areas  -- everything needed by  a small town Their design is  usually  temporary, although their useful life often extends beyond the period required solely for construction of the dam
The amount of land clearing for the camp is likely to be insignificant To the maximum extent
possible, trees should be left standing to provide comfort for the workers as well as supply a seed source once the camp is decommissioned If people are to be resettled to provide space for the camp, the resettlement policy currently followed by The World Bank should be followed
The amount of natural umber harvested for camp construction could be moderately significant if no precautions  are taken Ideally, such timber should come from the area of reservoir impoundment Outside that area, its  impacts  are identical to those of logging: destruction of native vegetation and disturbance to soil and water. To the maximum extent possible, the project should make use of such materials as plastic and metal sheeting, plywood and concrete
The camp electrical powerhouse will create insignificant impacts to the environment to keep noise to a minimum, the powerhouse should be located away from residents and receive regular maintenance
The camp water supply, if it is a large camp, could create drawdown to levels below the bottoms of nearby wells Affected households could be compensated by receiving camp supplies or by having then wells  rebored Ideally, nearby  households  should be relocated before the commencement of construction
Solid waste should be incinerated at a location removed from the camp and nearby households The design of sewage facilities should bear in mind whether or not the camp will continue to be used after its decommissioning If it is to continue in use, then primarv sewage treatment is required, otherwise, extensive septic systems might be permissible
Roads The construction of the Geba Dam requires  69 km of road improvement and the construction of one stream crossing The stream crossing depending upon ns type. could cause expansion ot the channel and disruption of aquatic life Roads have been shown to be an important contributor to so.l erosion, pnmarily because they concentrate and distribute runoff as channel flow rather than as uniform overland or subsurface flow
TAMS-VLG Baro-Akobo River Bavin Integrated Development MulerPU^
16
Chapter 2pREFEAsren.m studies
VOLUME v
Access  roads  will be constructed to a high physical standard (compaction, gradient, surface hardness) in order to accommodate the weight of heavy  equipment As  these roads  are likely  to be used for many  years  following dam construction, the major structures  should be designed to safely  pass  the 25-year flood and the minor structure to safely  pass  the 10-year flood Temporary roads  should be constructed to a permanent standard if their use will continue following completion of the dam or other structure.
Because roads  are an effective means  of access  to inaccessible areas, they  open areas  to increased exploitation logging, farming, hunting High standard roadways  should avoid intercepting primitive areas, national parks, controlled hunting areas  and locations  of exceptional histoneal or cultural significance unJess the means to control trespassing to these areas are available
The mitigations  of the potentially  negative impacts  of roadways  rest with competent engineering design Longitudinal drainage is  likely  to require a raised bed and ditches  Cross  drainage should follow existing channels  and be designed to accommodate debris  as  well as  water and sediment
Culvert  outflows  should  be  constructed  to  a  level  below  the  stream  bottom  so  as  not  to  interfere with  the  passage  of  aquatic  life  Culverts  on  steep  slopes  may  require  an  energy  dissipater  before they   discharge   onto   unprotected   land   A   Sod   Erosion   Control   Plan   should   be   developed   during the  project  design  and  precede  the  onset  of  construction  Its  purpose  is  to  provide  guidelines  for controlling soil erosion, sedimentation and pollution
The Soil Erosion Control Plan describes the location and type of controls to be implemented It
dearly identifies special resources, such as wetlands and primal forests that require protection
Perceived problems, such as highly erodible soils and unstable slopes, are clearly marked The
plan should contain basic drainage information, such as stream patterns, watershed areas, and the
size and location of hydraulic structures The erosion control measures should be in accordance
with the following principles:
•   Limit   the   time   and   area   of   exposure   The   potential   for   erosion   is   greatly   reduced   if   the size  of  the  disturbed  area  :s  small  or  its  duration  short  In  some  instances  stabilisation  can take  place  as  pan  of  construction  —  it  would  be  wrong  to  wait  until  the  final  grade  is established
•             Retain  sediment  on  the  site.  This  principle  is  achieved  by  using  devices  that  filler  sediment from  runoff  or  that  detain  runoff  so  that  heavy  panicles  will  settle.  It  includes  the  use  of materials such as silt fences, straw bales, brush barriers, and sediment traps and basins
•     Manage only the sediment and runoff from the site. For this discussion we are concerned
only   with   Geba   Dam,   not   with   regional   management   of   runoff   and   sediment   Diversion berms and channels might be required to divert clean runoff around the site.
Dam and appurtenant works.
Because much of the required fill will come from the reservoir impoundment area, its  impact upon the environment is  encapsulated within that of the reservoir. The demand for rockfill (nearly 0.5 mcm) require quarries  outside the reservoir area Quarn side slopes  should be graded io a gentle gradient prior to their decommissioning, the quarry floor should be sloping towards (he
1AMS-ULG Biirn-Akobo River Bum Integrated Development Muter Plan
17-
prefeasibility studies
V °Ll Mf; v
O-   4   Percent   are   impounded   Poor   to   the   rainy   season,   the   quarrv tack      cut      so      thata         tarn      in      otder      to      retain      runoff      Upon      decommission^ ^^^^ninotdectotedncethe-^ —
With  regard  to  diversion  works,  spoil  from  tunnel  borings  should  be  removed  to  a  protected  site isolated from streams, rivers, and the reservoir
Dislocation of people The study  by  ARDCO-GEOSERV (1995) shows  that 28 households  will be dislocated by  the Geba reservoir The World Bank  resettlement criteria for dislocated people should be followed The farmer gross  margins  for the reservoir area is  estimated to be 250 birr, or USS 40, per vear If relocation costs are taken to be equivalent to 3 years' revenue plus assets (estimated at USS 500), they  become USS 620 per household or USS 17,360 for the 28 households
Loss  of  land  The  reservoir  will  impound  90  km*  The  worth  of  its  standing  timber  as  dry  woody 
biomass  has  been  estimated  in  a  previous  paragraph  The  previous  assessment  shows  that  28
households  risk  being relocated It is  estimated that upland households  cultivate about 0 5 ha each Each household, on average, aggregates  an estimated gross  margin of about 250 Birr per vear from agriculture, thus  the total worth of the lost agriculture (less  assets) is  7,000 Bin per year (USS 1,120 per year)
[ne^nf  historic.  cultural  or  aesthetic  features  These  components  were  not  assessed  at  this  level of studv but remain for feasibility investigations
Loss  of  wildlife  habitat  The  impact  of  the  Geba  reservoir  upon  wildlands  and  wildlife  habitat is not assessed at this time It is a subject that will require attention during feasibility studies
Prohfergiion of aquatic  weeds During the dry  season, when inflows  are low and drawdown is advanced, the reservoir will become warm and its dissolved oxygen will deplete it is likely that aquatic  growths  will occur It is  not expected that they  proliferate to such an extent that they pose problems to the dam operations or fishery developments
l   lorerioranon   of   water   quality   Water   quality   is   affected   when   large  amounts   of   tropical vegetation are flooded by new reservoirs The two important parameters to the process arc the amount of biomass and the residence time of the water in the reservoir From a totally empirical assessment of the Geba Reservoir, it would seem that the short residence time coupled to the small reservoir area would place the reservoir out of the severe risk category For the purpose of this prefeasibility study, it is, however, recommended that the reservoir area be totally cleared of  all  biodegradable  biomass  In  addition,  a  multilevel  outlet  should  be  considered  to  release water from different levels
h^crvoir sedimentation The reservoir will likely  accumulate coarse sediments  at its  mlet and atpnncipal inlets along its flanks Fine sediments nw develop into density currents that will cany as  far as  the dam face, where they  will be flushed through the low level outlet Sediment accumulation in the reservoir is estimated to be 1 320,000 cubic metres per year Pnor to des.gn a sediment measurement campaign should be undertaken to confirm the estimate The reservoir dead storage is des.gned to accommodate a minimum of 50 years of sedimentation
TAMS-VLG Bar»>-Akobo River Bavin Integrated Development Matter Plan
18PREFEASIBILJTY STUDIES
VOLUME V
Rivenne fishenes The reservoir may  intenupl fish migrations, but this  has  not been directly assessed during the course of this  or previous  studies  A fish ladder and hatchery  should e considered
liaier-relaied diseases At this  level of prefeasibility  study  an assessment of the Geba reservoir with regard to water-related diseases  is  speculative, only  some indications  can be drawn from outside the project area and, indeed, from outside Ethiopia
The risk  of malaria and other diseases  related to mosquitoes, gnats, midges, and other insect carriers  that breed or depend upon waler (yellow fever, dengue. Onchocerciasis) will change from being seasonal to becoming perennial The increase will result from improved breeding habitat offered by  the reservoir and ils  shoreline vegetation. Some of the risks  associated with these diseases  can be reduced by  controlling wetland vegetation, possibly  by  recession grazing Anti- malarial programs  using pesticides  such as  DDT pose their own set of hazards  and costs, and are not recommended given that many  of these substances  are banned Similarly, chemoprophylaxis is  at best suitable only  for short-term, non-immune visitors  to the project area The development of immunity  and treatment of the population living near the reserv  oir is, for now, an admittedly partial solution
Schistosomiasis  does  not present the same risk  for hydroelectric  reservoirs  as  it does  for irrigation, which brings  man into intimate contact with water At the Geba site, the potential for infection is  unknown given that we have no information about the presence of Biomphalaria or Buhnus.
Infection  would  affect  people  w  ho  used  the  reservoir  for  recreation  or  as  a  source  of  domestic water  The  greatest  risk  would  be  on  the  lee  shore  of  the  reservoir,  especially  if  vegetation  were allowed  to  accumulate  there  An  obvious  control  is  to  exclude  the  human  population  for  the  shore area,  coupled  with  training  in  hygiene  and  health  If  the  reservoir  wrere  intended  to  supply  water to nearby households, then water stations removed from the perimeter offer another response
Trypanosomiasis does not appear to be known high in the upland watersheds, but information
about this disease is fragmentary and inconsistent Selkhozpromexport (1988) reported an
unconfirmed 454 cases in the upper Gilo River, but this is believed to be adjacent to the low lands 
Feasibility studies will need to gather information on the frequency of this disease in proximity 
to the site
Selkhozpromexport (1988) reported the absence of the mosquito earners  of Leishmaniasis  in the lower basin There is  no information about their presence in the vicinity  of Geba reservoir or, indeed, their continued absence in the lower basin The risk  of helminthiasis  from hydroelectric projects  is  low as  this  kind of project does  not call for the same land of intimate contact between man, soil, and water as does irrigation.
Cog/frc/gig demands jbr wq/er Provisional minimal continuous  releases  from the Geba Dam and its  in-line diversions  are computed at 8 percent of mean annual discharge or 0 70m Vs. Feasibility studies  will be required to evaluate the effectiveness  of this  discharge io sustain present populations  of water organisms  and competing water users  The present study  has  not computed a flow duration curve based on mean daily  discharge. from which minimal flow requirements  are usually estimated
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Chapter 2PREFEASIBlLm STUDIES
VOLUME v
_________________ _____
lncre^edjat^pressure The Geba reservoir will require the relocation of 28 households 
incrvujcu
r
- —. 1HC UUVd ivdWTVM
,
‘       nA Um2? arAQ
currently resident in its 90 Ion area The development
is unlikely to attract an influx of p
eop e
|
into the area other than for the dam construction
2.5      The Recommended Project
2.5.1 Project Description
The Geba Project storage dam is located on the Geba River at the downstream end of a wide
flood plain, where substantial storage can be developed with a low dam At the site the drainage
area is 1.086 square kilometres At full pool elevation 2170 the reservoir has a surface area of
about 66 km*. at minimum pool elevation 2145 the surface area reduces to about 10 km* The
dam is 45 m high above the river bed with a crest elevation of 2175 It is of zoned earthfill
construction.
The spillway  is  ungated, 80 metres  long, with a crest at elevation 2170 During passage of the PMF the maximum surcharge will be 2 metres  Downstream of the crest, the chute narrows  to 53 metres and terminates in a 25 by 53 by 7 metre deep stilling basin The total length of chute and stilling basin is 450 metres
The two diversion tunnels  are 4.2 m in diameter and 500 metres  long The diversion dam is of 15 metres maximum height One of the tunnels will be converted to a low-level outlet for making power releases The control shaft could be constructed before diversion, but gate, hoist and sei frame installation, and second stage concreting, will have to be done after diversion, with the other tunnel remaining open to pass  the nver flows  during this operation The control shaft will have gates at three levels for selective withdrawal purposes, and two sets of high-pressure slide gates, one senice, the other emergency, will be provided just downstream of the selective withdrawal shaft The senice gates  will be closed dunng operation of the selective withdrawal gates so the latter can always be operated under balanced head A small stilling basin is provided at the downstream end of this  tunnel for energy  dissipation dunng operation at high reservoir levels
The first pow er diversion is located 4 kilometres downstream of the dam The diversion weir is an uneated concrete ogee section, 80 metres long On the left bank a canal intake structure will be built, equipped with 10-3x1 5 m sluice gates Downstream of the intake structure, the canal, sized for 51 7 mJ/s, the peak power flow will generally have a 12 metre bottom width and a 4 metre depth It is expected that it will be mostly excavated in rock and will be concrete-lined
3-metre wide access and maintenance roads will be provided on both banks The canal will have a total length of 3500 metres When more is known about the topography and condition of the rock it mav prove advantageous to size the canal for the mean daily power flow and provide a XregUung reserv oir at the head of the penstock for daily pondage.
The penstock is 3 2 metres in diameter and 700 metres long to develop a total head of275 metres The maximum plate thickness is 30 mm
TAMS-ULG Baro-Akobo Rher Baiin Integrated Development Master Plaa
20PREFEASIBI1.ITY STUDIES
VOLUME V
Al the powerhouse the penstock  will feed a manifold and supply  four 28-MW turbine-generators Alternatively, it might be preferable, with staged development, to construct one 2 25-m diameter penstock  to supply  two 28-MW units, and build a second penstock  at a later time Upstream of lhe turbine, each branch pipe will be provided with a 1.40m diameter inlet valve to allow isolation of individual units
Each 28 MW generating set will consist of a Francis  turbine having a runner discharge diameter of 1 10 m and a 10-pole generator which will be rotating at 600 rpm The powerhouse, which will consist of four generating bays  and one service bay, will be 35 metres  long by  12 metres  wide, and the bottom of the draft tube will be located approximately  9 metres  below the normal minimum tailwater level Tailrace will be very short or non-existent
The four transformers  are anticipated to be located at the pow erhouse above the manifold (on the hillside) with the switchyard located on a Cat area approximately  500 metres  from the powerhouse above the flood plain The switchyard will consist of 8 bays  (2 lines, 4 units, local loads  and bus tie), approximately  15 metres  wide by  100 metres  long for a total surface area of 120 metres  by 
100 metres
The  second  power  diversion  is  located  13  km  downstream  of  the  first,  or  a  total  of  17  km  from the   dam   The   diversion   weir,   the   intake   and   the   canal   cross-section   would   all   be   similar   to diversion   no   1,   with   appropriate   modifications   due   to   differences   in   topography   and   geology' The  power  canal  would  be  6000  metres  long  leading  to  a  penstock  3.2  metres  in  diameter  and  400 metres   long   to   develop   a   total   head   of   175   metres   The   maximum   plate   thickness   for   this penstock   is   20   mm   At   the   powerhouse   lhe   penstock   will   trifurcate   to   serve   three   24-MW   units in  the  powerhouse  Each  Francis  turbine  will  be  provided  with  a  1  50  metre  diameter  inlet  valve and  will  have  a  runner  discharge  diameter  of  1.30  metres.  The  12-pole  generators  will  rotate  al 500 rpm
The powerhouse will have a total of three generating bays  and one service bay  and will be 30 metres  long by  14 metres  wide The draft tube bottom will be 8 metres  below the normal minimum tailwater level Similarly to Diversion No. 1, the tailrace is anticipated to be short.
The three transformers will be located on lhe top of the manifold The switchyard will consist of
9 bays (4 lines. 3 units, local loads and bus tie), each approximately 15 metres wide by 100 metres 
long for a total area of 135 metres by 100 metres. This power plant is located only about !4 km
from the Metu-Bedele road, near the village of Achibo
2.5.2 Quantity and Cost Estimate
Layouts, profiles  and sections  have been developed in sufficient detail (see Drawings  GE-1 to GF.- 12) to obtain quantities  appropriate to (he prefeasibility  level In addition to major cost elements such as  excavation, concrete and earthfili, quantities  have been computed for such items  as formwork, reinforcing steel, drilling and grouting rock anchors, gates and other items.
Unit prices used to develop the detailed cost estimate are shown on Table 2.10. These were derived from bids lor a similar project subjected to international competitive bidding in Africa and South America and adjusted to a common January 1996 price level
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Chapter 2PREFEAsronm studies
VOLUME V
Table 2.10 Unit Prices (January 1996)
hem_________
Common Excavation RockExcavation
Portal Excavation
Tunnel Excavation
Borrow Excavation - Common
Borrow Excavation - Rock
Mass Concrete
m'
90 39
Structural Concrete
m’
129 94
Concrete lininst itunnel)
m                                     203 38
Formwork
m‘
50 85
Steel Reinforcement
T                                      1,242 90
Unprocessed Fill (placement)                                     m
226
Processed Fill (placement)
m
6 78
Filters
nr
1695
| Drains. Transitions
m                                     Il 30
1 Impervious Core
m5                                                     565
I Drilling!confined space)
m
79 09
1 Drilling (open space)
m                                    56 50
1 Grouting
T
564 96
1 Tunnel Suppor. - Rock Bolts
T
6,779
Tunnel Support - Shotcrete
n/
2825
| Tunnel Support - Arches and Ribs
T
2.260
A detailed cost estimate is presented in Appendix 2-1 and summarised in Table 2 11
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Chapter 2PREFEASIBIUTY STUDIES
VOLUME V
Table 2.11 Geba Hydroelectric Project Cost Estimate (USS-January 1996)
Dsm & Appurtenant Works
Civ'll Works
35,430.000
Equipment
1,420.000
Power Plant and Waterway No 1
Civil Works
Equipment
15,320.000
51,970,000
Power Plant and Waterway  No 2
.
Civil Works
19,850,000
1              Eq2uLip£mLent
-----    r.    ---- ---------- ----- Transmission Lines
36 000 000
31,500,000
| Subtotal
191,480.000
Contingencies (20%)
38,300.000
j Eng. & Adm (10%)
22,980,000
Total Construction Cost
252,760,000
2. 5.3 Implementation Sc/t edule
ft is  anticipated that feasibility  studies, design and preparation of bid documents  for the Geba Project would require about 216 years, providing that large scale topographic  mapping and geotechnical exploration could be made promptly  available Allowing 6 months  for review of the bid documents  by  the Owner and the lending agencies, and for the bidding process, construction could start 36 months  after commencement of the feasibility  study  Depending on the electric power demand at the lime, the availability  of transmission facilities, and the availability  of funds, it might be decided to build the Geba storage project Only  the first half (2-28 MW units) of the first diversion will be constructed initially, with a consequent reduction in the initial capita] requirements  Based on the current power demand projections, it is  however anticipated that power will be needed at the time of commissioning, and at least all 112 MW could be used initially  The construction of the dam (and access  road) spillway  and outlet works, along with the first stage of the power diversion, canal, penstock  and powerhouse would require 3 to 316 years, if only  because of lead time required for the outlet gates, penstock  and powerhouse electro- mechanical equipment Thus  it may  be envisioned that first power from this  project could be available about 6 years after commencement of the feasibility studies
Figure   2   4   shows   the   anticipated   construction   schedule,   assuming   that  the   power   Diversion   No 2 would be developed with one year lag
2.6      Economic Appraisal
The Geba Hydroelectric  Project ml] form pan of the ICS and therefore should be evaluated as a candidate project in the generation expansion plan of the system Essentially  it should be demonstrated that the inclusion of the Geba project represents  the least cost expansion plan for the system.
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23
Chapter 2prefeasibility studies
VOLUME v
At this  time the polio' in the power sector is  in transition from the consideration of large projects, such as  Aleltu and Chemoga-Yeda. to medium-sized projects  such as  Gojeb and Tekeze. As  a consequence there is  no defined least cost expansion plan of the system. The next best option fOr the economic  appraisal is  to determine the long run marginal cost of energy  and to use this  to evaluate benefits  for candidate projects. Studies  into interconnections  with neighbouring countries  have used a value of USS 0 06 per kWh as  the long run marginal cost of energy  This value was used for lhe present assessment
As  a check  on the economic  strength of Geba, comparison was  made with other projects  under consideration for the expansion of the ICS. using such parameters  as  the unit energy  production cost and the cost of installed capacity
As  demonstrated in Section 2 3 5, the economic  internal rate of return of the Geba projeci, using an energy  value of USS 0.06 per kWh, is  16 4%. This  high value is  a good indication of the economic strength of the project
Comparisons with other candidate projects are given in the following tabulation
Cost of Installed Capacity (USS per kW)
Geba 1 and 11 Gojeb
Aleltu East I
Aleltu West
Halele-Wercbesa Chemoga-Yeda I & Il
1391
1740
2053
2865
2400
1816
It  can  be  seen  from  the  above  that  the  Geba  project  compares  very  favourably  with  any  alternative hydropower projects presently under consideration
Finally  the  low  energy  production  cost  for  the  Geba  project,  at  about  US$  0  038  per  kWh,  is significantly cheaper than any thermal plant option
TAMS-ULG Ban>Akolx» River Biviu Inr^rittd Development Mailer Plan
Chapter 2PREFEASIBILITY STUDIES
VOLUME V
3. GUMERO HYDROELECTRIC PROJECT
3.1       Introduction
3,1.1     Project Concept
The Master Planning studies  have identified a number of small hydroelectric  projects  in the Baro- Akobo basin that would be suitable to meet the relatively  small regional demand for electric power The most promising of these projects  is  the Gumero scheme, located on the upper reaches of the Gumero River approximately 27 km west of Metu
The project consists  of a regulating reservoir downstream of a relatively  steep area in the upper catchment of the Gumero. and ihree downstream hydroelectric  diversions  where head is developed by  bypassing steep reaches  of the river using canal surface penstock  and surface powerhouse. Drawing No. GU-1 (Appendix  3-1) shows  the locations  of the dam and the three power diversions which can develop about 12 MW. 18 MW and 20 MW respectively
The project can be implemented for supply  of electricity  in the basin as  a staged development with each successive power plant coming on line at the time when n is  needed to meet the growing demand Alternatively, as  EELPA has  already  initialed the connection of the region to the ICS, the scheme could be built more rapidly  and export power to nearby  adjacent regions  Decisions regarding the project implementation will be addressed at the feasibility  level It is  however clear that the GumeTo project is  an economically  attractive alternative for the supply  of power in the region
3. 1. 2 Project Area
The project area is  located on the Gumero River about 6 km upstream of its  junction with the Ofa and 32 km upstream of the latter’s  junction with the Birbir River. The storage dam site is  27 km west of Metu and, at its  closest point, the Gore-Gambela road is  9 km south of the site The dam site area is  forested, with moderate relief, The reservoir area is  within the Gumero flood plain with numerous  houses  and considerable agricultural development on the hilltops  surrounding the reservoir Land slopes  at the site are about 10% and the river gradient is  about 0.12% At the diversion sites, all on the Ofa River, the cross  slopes  are about 15 - 30% and the river gradient ranges  between 3 and 8% The Gumero River rises  to the southeast of the dam site al about elevation 2000 At the site itself the river is  at elevation 1580, falling to elevation 1340, 1120 and 800 al the powerhouses for Diversions 1, 2 and 3 respectively.
3.1.3 Potver Planning
The Baro-Akobo basin has  a limited number of isolated diesel power plants. In their survey  of 1993. ARDCO-GEOSERV has  identified four such plants  at Nekempte, Ghimbi, Asosa and Bonga for a total installed capacity of 3.19 MW There are also two hydroelectric projects in the
TAMS-ULG Baro-Akobo River Baiin Integrated Development Muter Plan '
25
ChkntTrFprefeasibility studies
VOLUME v
, • fSMW) and near Muan Tefen (800 kW) Globally  for the three regions covering hX MoboTain. Wollega, Sor and Bonga, the total electricity  sales  in 993 were 8.33
GWh Promos  for these regions  average growth rates  of 7 4% for energyesland 5^5% for peak power demand (Figure 3.1) over the next twenty years It is^anticipated that the peak power dmL in 2020 will reach 61 MU' In that context, it is  expected that a project such as  Gumero with the potential for an installed capacity  of approximately  50 MV* would be a sunable sitt power project for the vear 2020 horizon Furthermore the Project, by  ns  nature, a cascade of three hvdrodectnc installations, is well set to be staged and to provide peak power as the regional demand grows It should also be noted that EELPA is planning connection to the ICS in the near future with two ties in the basin at Ghimbi and Sor scheduled for 1999 and 2000. respectively
3.2      Basic Data
3.2.1    Topography
The only  topographic  mapping available is  from the Russian aerial photography  of 1984 The scale of these maps is 1:50,000 with a contour interval of 20 metres and supplementary contours of 10 metres
3.2.2    Hydrology
The Gumero storage dam is on the Gumero River and it has a catchment area of 443 km2 The hydrometric network of the Baro River basin, which includes the Gumero River, is poor with a total of 10 siations and only two stations having more than twelve years of records These are on the Baro River at Gambela and on the Sor River at Metu where the catchment areas are 23,461 km" and 1.648 km" respectively There is one gauging station on the Gumero upstream of the site with a significantly small catchment area (106 km )
The river flow at the location of the dam was estimated in accordance with the methodology developed in .Annex IB - Hydrology of the Master Plan The methodology used consisted in:
infilling gap by linear repression,
correlation between monthly flows and rainfall for a set of representative stations near the catchment, and
stochastic modelling to generate long-term (41 years) monthly flow series Table 3 1 shows the long-term monthly average at the dam site
Table 3.1 Average Monthly Hows at Gumero Dam (m /s)
2
2
1
January                           1 46
1
Juiv
17 50
February                          1 00
August
20 96
March                               063
September
23 77
April                                 0 76
October
18 77
May
2.58
November
6 27
June                                 7.67
December
2 54
TAMS-ULG Baro-Akobo River Bar in Integrated Development Mailer Plan
Chapter 3PEAK POWER DEMAND (MW)
Baro-Akobo Basin
Peak Power Demand Forecast
Figure 3-1PREFEASIBILITY STUDIES
The long-term mean annual flow is 8 66 (249 mcm) occurs during the six wettest
VOLUME V
m’/sec or 273 mcm Approximately 91% of that runoff months of the year from June to November
Uane 'he available flow records  in the basin, a flood frequency  analysis  was  performed to Pennine flow for Afferent return periods  at the Gumero site The results  of ths  analysis, (Awx 1C) which are shown on Table 3 2, were based on the Sor River gauging station
Table 3.2 Flood Frequency Analysis at Gumero Dam
Return Period
Discharge (mJ/s)
lOvear
182
100 vear
313
500 veai
462
For the meteorological and rainfall gauging stations located in the vicinity of the basin, a statistical analvsis  of the maximum daily  precipitation was  performed Applying the Hershfield methodology, as indicated in .Annex 1C - Flood Studies of the Master Plan, the precipitation data were used to estimate the 24-hour Probable Maximum Precipitation (PMP) at these various rainfall stations. The results of this analysis are shown on Table 3-3
Table 3.3 Probable Maximum Precipitation
i Stations
24-Hour PMP (mm)
I Gore
400
1 Metu
336
| Hummu
501
Based on this analysis the 24-hour point PMP for the Gumero catchment area was estimated to be 400 mm For the purpose of this prefeasibility study, a simplified HEC-1 model was developed to estimate the inflow hydrograph of the spillway design flood The peak discharge is estimated to be 720 m’sec
There is no available data on suspended sediment in the vicinity of the site For the purpose of planning the reservoir operation, studies considered the accumulation of sediment in the reservoir A discussion of the sedimentation estimate for all reviewed reservoirs is presented in Annex IF
to the Master Plan Report The annual rate of deposition in the Gumero reservoir was estimated
to be 674,000 mJ
3.2.3   Site Geology
The Gumero dam site is on the Gumero River 35 km upstream of the junction with the Birbir and 28 km northwest of Gore The dam site is shown on the geological sketch map at 1 60.000 scale and lies  on Mekonnen Basalt overlying hornblende and biotite gneisses  On the 1 250 000 geological map and the published Gore sheet only gneisses are shown in the area The site is covered by aerial photos, stnp 14, photos 1584 and 1585 The area has moderate relief and the valley sides are forested at the dam site The uplands in the vicinity of the dam site are cultivated and have rounded slopes No large areas of rock are seen immediately near the dam site bul
TAMS-ULG Baro-Akobo River Batin Integrifed Development Master Plan
27PREFEASIBILITY STUDIES
approximately 6 km north northwest of the dam site, at Guracha Mountain. basement gneisses with distinct foliation striations outcrop and a rockfill quarry here would be easy to develop. 1 he
VOLUME V
uentle slopes outside the steep valley' rim reputedly have suitable residual clay for impervious fill
Basalts may also be available for a rockfill quarry No sand and gravel deposits occur in the area
A rockfill dam is recommended for this site A diversion tunnel should be easily constructed in
either basalts or gneisses with support of shotcrete, w ire mesh and rockbolts
3.3        Project Development
J. 3.1 Project Options
Based on aerial photographic  interpretation, a suitable quarry  could be developed at Guracha mountain, about six  kilometres  north of the site, which would require overhaul However, rock reportedly  also outcrops  on the right river bank  at (he site. A field survey  would be required to determine the correct material for dam construction, but at this  prefeasibility  level of study, a rockfill dam has been selected
With a 180-metre head available at the end of a 2,300-metre-long canal, a first stage run-of-river development at the Gumero 2 diversion site might be considered However, it does  not appear likely that the flow would be sufficient to justify the high cost of such a small project
It appears  possible that a project to irrigate the bottom lands  upstream of the proposed hydroelectric  storage dam site would be feasible A site for storage for such a project has  been identified 15 km upstream of the hydro site However, the area under command is  small, and considering the probable value of developing (he total 500 m of head for hydroelectricity, this option was not pursued
.As   previously   noted,   the   only   topography   available   is   at   a   scale   of   1   50,000   with   20   metre contours   From   this   topography,   the   site   and   arrangement   of   structures   is   appropriate,   and   the quantity   and   cost   estimates   have   been   prepared   accordingly.   When   more   detailed,   and   larger scale,  topography  becomes  available,  it  may  well  be  that  a  more  economical  site  can  be  found,  or in any event that a more realistic and economic layout and arrangement of structures can be made
3.3.2 Reservoir Operation Stu dies
As  indicated above, the reservoir will regulate the river flow to be used at three downstream hydroelectric  power plants  The HEC-5 computer model was  used to estimate the yield or firm flow, that can be guaranteed by  operating the reservoir so as  to release a constant flow' For the purpose of this  study, the yield was  defined as  (he constant monthly  discharge for which the long term average deficit is  2% of the yield (98% reliability) The HEC-5 model performs  a monthly routing of the 41-year long flow time series  at the dam site (Table 3 4) Figure 3.2 show's  the yield in tr.Vs  of the Gumero river at the dam location as  a function of the reservoir active storage
This   curve   was   used   to   estimate   the   yield   of   the   reservoir   for   a   set   of   maximum   reservoir operating levels,
TAMS-ULG Barn-Akobu River Buin Integrated Development Muter Plan
Chapter^2
Table 3-4
Monthly Flows at Gumero Dam (m3/sec)Firm Flow(m3/s)
Gumero River at Gumero Dam Site
Yield Curve at 98% Reliability
Figure 3.2PREFEASIBILITY STUDIES
V OLl
v
The active storage of each reservoir was  determined as  the storage above El 1,600 taking ini0 account the accumulation of 50 years  of sediment The area-capacity  curve of the sedimented reservoir was  determined by  the use of the methodology  developed by  Borland, Miller and Moody  Table 3.5 shows  the firm flow at 98% reliability  for the three reservoirs  selected fOr optimisation of the Gumero project Figure 3.3 shows  the results  of this  computation for the reservoir with a maximum operating level at El 1,610
Table 3.5 Gumero Reservoir Firm Flow (m /s)
3
Maximum Reservoir Level          Active Storage (mem)
Firm Flow (m'/s)
El 1.605                                             92
6.50
El 1.610                                           244                                                   7 80
El 1.615
488
8 20
--------------------- --------- -----------1
For each of these selected reservoir levels, the firm energy generated annually by the project was determined assuming an overall efficiency of 85%, and waterway head losses of 6% The gross heads developed at the first, second and third power diversions are 120 metres, 180 metres and 205 metres respectively Table 3.6 shows the annual firm energy generated by the project for each of the selected maximum operating pool
Table 3.6 Gumero Hydroelectric Project - Annual Firm Energy (GWh)
Maximum Reservoir
1 Level
Diversion No.l Firm Diversion No.2 Firm Energy (GWh/yr)        Energy (GWh/yr)
El 1,605                            53 6                                   804
El 1,610
64.3
965
Diversion No.3 Firm
Energy (GWh/vr)
■ - — --------------- - ---— 916
1099
El 1.615                            67 6                                 101 4                             1155
3.3.3   Access and Transmission Lines
As previously noted, the main Gumero storage dam is about 9 km from the Gore-Gambela road in country with moderate relief An all-new road along such an alignment from this road would appeal to be the best choice for access to the site .An alternative would be to improve the existing Metu-Bumsa road and build a new road about 4 km long from the Burusa road to the dam site The former alternative has been chosen for the prefeasibility study
There does not appear to be an existing access anywhere near the three diversion sites It will probably be necessary, therefore, to construct an access road through difficult terrain and along the right bank of the river, where a!) three diversions are located From the dam to Diversion I is 8.5 km as the crow flies. 4 5 km further to Diversion 2, and an additional 15 km from Diversion 2 to Diversion 3
Since the Gumero project is proposed primarily to generate electricity for use within the Baro basin, the transmission line should connect directly to the existing Sor-Metu-Gore-Gambeia 66 kV line. 9 km from the site However, at full development (all 3 diversions), the total transmission line length would be at least 37 km.
TAMS-ULG Barv-Akobo River Bn»in Integrated Development Muter Plan
Chapter JElevation in meters
Area in km2
Figure 3-3FREFEASBIUn STUDIES
VOLtMt,,
jjj Project Layout
Ras«i on the small-scale (1 50,000) topography, the dam. spillway and outlet works arrangement aoZrs  to be the most favourable The dam is  at the downstream end of a marshy, almost f]at I ?km wide plain where a substantial amount of storage can be developed with a low (33 p,) d Jn. and without infringing on existing dev elopment on the nearby lull tops
For the spillwav and outlet works, the right abutment as well as the left, were considered On the right bank, a spillway crest and chute structure would appear to require less excavation but could present a hazard to the embankment dam, since rock is probably lower there than on the left The diversion tunnel also would appear to be shorter, but the lesser overburden could produce tunnelling problems
On the other hand, on the left bank there is a high knob. 15 metres above dam crest, that could separate the spillway crest structure from the dam abutment, and might also be indicative of
harder rock for tunnelling Consequently, in the absence of larger scale topography or any 
detailed geophysical information, both spillway and outlet works were located on the left
abutment
.All three power diversions have been located on the evidence of the small-scale I 50,000 maps Judging from contours on these maps, the locations appear reasonable, and likely canal routes,
all located on the right bank of the Ofa River, appear feasible at the mapping scale available
.Alternatives will only be able to be studied when larger scale topography, and field geotechnical reconnaissance, becomes possible
3.3.5 Project Selection and Optimisation
For the purpose of selecting the size of the project to be developed at the Gumero site, cost estimates  for three levels  of reservoir were prepared The project-installed capacity  has  been selected to proude a project plant factor of approximately 60% .As a consequence, for each reserv oir level selected the installed capacity is determined by the firm yield of the reservoir at that level
Since the hydroelectric benefits of the project do not depend on the head created by the storage dam, the minimum reservoir operating level is  selected as  the minimum technical Jd environmentally feasible, taking into account the estimated sediment deposit in the reservoir over the life of the project On that basis the minimum reservoir level selected is at El 1,600 Table 3.7 shows the main characteristics of the projects selected for optimisation
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Chapter 3PREFEASIBILITY STUDIES
VOLUME V
Table 3.7 Project Optimisation Reservoir and Power Plant Characteristics
Minimum Reservoir Level
1 600
1,600
1,600
Maximum Reservoir Level
1.605
1,610
1 615
Average Reflated Discharge im 7s)
65
7,8
82
Max Power Discharge (tn 7s)
108
13 0
13 7
Diversion No. 1 Head im)
120
120
120
Diversion No 1 Capacity (MW)
10.2
12 2
12.9
Diversion No 2 Head <m)
180
180
180
Diversion No 2 Capacity < MW i
15 J
184
19.3
Diversion No 3 Head t m)
200
200
200
Diversion No 3 Capacity * MW)
174
21 0
220
The cost estimate for each of these projects  was  prepared in accordance with the methodology established in Annex  IG, Water Resources  Cost Estimating of the Master Plan A summary' of the major cost items is shown on Table 3 8
The project size selection was  made on the basis  of the highest internal rate of return (IRR), taking into account the feasibility  study, design and administration costs, the cost of construction allocated over a period of four years, the cost of operation and maintenance and the revenue from the sales of firm energy
.As  shown  on  Table  3  8,  the  costs  for  engineering  and  administration  of  the  project  have  been estimated at 10% of the total construction cost
The   cost   of   operation   and   maintenance   over   the   50-year   life   of   the   project   were   estimated   as follows
0 5% for civil works
2.5% for electromechanical equipment
I 0% for transmission lines
Revenues  from  the  sales  of  firm  energy  were  estimated  at  the  rate  of  USS  0  07/kWh  (January 1996)
For purpose of this  analysis  the three power plants  were built to meet the expected power demand of the Baro Basin The first power station would come on line in 2005, the second in 201 1 and the third m 2019.
TAMS-LLG Burn-A kobo River Basin Inicgrated Deselopnitnt Master Plan
32
Chapter 3Table 3.8
Project Optimization - Cost Estimate (USS ’000)
Prce Level January 1996
mrv Mat                           Level
El. 1,60$
El. 1,61 Ol
El. 1,615
(Xv No 1 Inst Cap
10.2 MW
12.2 MW
12.9 MW
.
niv Mo 2 Inst Cap
1S.3MW
11.4 MW
19.3 MW
Dry, No.3 Inst Cap.
17.4 MW
21.0 MW
22.0 MW
Preliminary
1.729
2,124
2 557
Mar Dam
8.448
11 081
13963
Access Road
400
400
400
Diverse" Tunnel
1 920
1920
1 920
Sptliway
545
545
545
Low Level Outlet 216 216 216
Subtotal 13.259               16,217           11.601
Power Plant & Conveyance
Diversion No. 1
Subtotal 6,926
Diversion No. 2
11.113           11.527
Subtotal 12.649
Diversion No. 3
14.286           14,765
Subtotal 20.133
22.770           23.792
Transmission System
Preltmxury
813
824
827
Switchyard Dry No1
550
550
550
Switchyard Drv No2
550
580
591
Switchyard Div Ng3
568
611
625
'ransrrvssKin Loe
3 750
3 750
3750
Subtotal 8,231
6.315             6,343
[
Total Direct Cott| 84,413 | 95,343 ) 103,24F|prefeasiblltty studies
VOLUME V
Based  on  these  assumptions,  the  IRR  of  the  three  selected  schemes  were  computed  as  shown  on Table 3.9
Table 3-9 Project Optimisation - Internal Rate of Return
’ Maximum Reservoir Level
1605
1610
Diversion No 1 Inst Cap
102
12.2
12.9
Di version No. 2 Inst Cap
15.3
IS 4
19.3
Diversion No 3 Inst Cap
17.4
2.1 0
22.0
Total Construction Cost (' USS mil)
84.4
95.3
103 2
Annual O & M Cost (USS mil»
1 06
1.24
131
Firm Energy (GWH/yr)
225
271
285
Annual Revenue CLFSS mil)
15.78
18 95
19 94
IRR'%)
1] 0%
1 1 4%
11.0%
On  that  basis,  the  Gumero  project  with  a  maximum  operating  pool  at  El  1,610  was  selected  The installed  capacity  of  each  of  the  power  plants  was  selected  to  meet  the  60%  plant  factor  criteria
Each  power  plant  will  be  equipped  with  two  units.  The  total  installed  capacity  of  the  project  at full development will be 51.6 XW
3.4       Environmental Assessment
The Gumero Dam will impound the Gumero River about 35 km upstream of its  confluence with the Birbir River Its  site lies  in the upland portion of the Illubabor Region The crest length of the dam is  700 m, its  maximum height 35 m and its  construction rockfill The reservoir would inundate 30 9 km2 to contain 300 million cubic  metres  (mcm) of water Its  normal minimum operating level is  at El 1,600 and its  maximum level is  at El 1,610 m elevation The mean annual flow of the Gumero River at this  location is  estimated to be 8 7m7s  Discharge from the dam would be diverted to generate electricity  at 3 hydropower installations, each of which is  serviced by a separate, in-line diversion of the Gumero River
Positive impacts
The subsequent section discusses the potential non-hydroelectric benefits of hydropower
Flood control The flood surcharge volume of the reservoir is  300 mcm in addition to its  active storage of 160 mcm Flood attenuation will undoubtedly  occur as  a result of normal reservoir operations  However, flood control is  not the pnrnary  purpose of the reserv  oir, and based on the review of the 1 50,000 scale map, it appears  there is  practically  no settlement on the Gumero and the Ofa rivers downstream of the dam site.
Reservoir fisheries Neither the study  by  Selkhozpromexport nor ARDCO-GEOSERV provides fisheries  estimates  for impoundments  in the upper basin Selkhozpromexport (1988) estimated that the Abobo reservoir in the lower basin could produce an annual catch of 100 t for its
1AMS-ULC Baro-Akobo River Basin Integrated Development Master Plan
Chapter 3
o.
1—‘
•J* 1PREFEASIBILITV STUDIES
VOLUMEv
2 210 hectares  reservoir This  result cannot be extrapolated to upland reservoirs, howey*
without further study
Fuebood  -Among  the  mitigations  recommended  by  this  assessment  is  the  total  clearance  Of
biodewadable  material  from  the  reservoir  area  The  woody  biomass  of  the  darn  and  reserv01r
s te
i
2
has not beer, sun eyed other than in the context of the 1995 Woody Biomass Survey by Theriault Using his results, the reservoir lies in an area whose potential dry woody biomass lies between 30 and 50 t/ha For the area of the reservoir (30.9 km ), this translates into a potential fuel wood supply of between 92,700 and 154,500 tonnes At 5 Birr per 20 kg bundle of fuelwood, its gross resale value, exclusive of the cost of collection and preparation, is between 23 and 39 million Bin (USS 3 7 and 6 I million).
Recessionagriculture and grazing The reservoir offers  the potential for recession grazing and agriculture during the dry season Poorly drained areas have been traditionally used for dryland grazing in much of Ethiopia, recession agriculture in the upper basin is  much less well-known
Given the small difference between minimum and maximum reservoir operating lev els. shorelines are likely to be broad and undulating, and grazing production could flourish as. indeed, it does in natural basins  and many reservoirs throughout the country II is a resource suitable for control and regulation through a permit system, which could be a source of revenue
Negative environmental impacts and their mitigations
Large dam projects cause irreversible environmental changes over a wide geographic area and thus have the potential for significant impacts The area of influence of a dam project extends from the upper limits of the catchment to far downstream While there are direct environmental impacts  associated with the construction of the dam, the greatest impacts  result from the impoundment of water and alteration of water flow downstream These effects  have direct impacts on sods, vegetation, wildlife and wildlands, fisheries, climate, and human population in the area "lhe dam s indirect effects include those associated with the building and maintenance of the dam the operation of the reservoir and the development of agricultural, industrial or municipal activities made possible by the dam,
The negative environmental impacts that result from dams and reservoirs could include the following:
•    Construction camp,
•    Roads, and
•    Dam and appurtenant works.
•    Dislocation of people.
•    Loss of land
•    Loss  of histone or other features,
•    Loss  of wildlife habitat,
•     Proliferation of aquatic weeds. Detenoration of w ater quality,
r
•     Reservoir sedimentation,
•     Riverine fisheries.
•    Water-related diseases.
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Conflicting demands for water, and
* Increased land pressure
Construction   camp   Construction   camps   usually 
compris
e
quart
ers 
for   bet
ween   200   and   600   men,
and   contain   showers,   cooking   facilities,   toilets.
genera
to
rs,   fu
el
dumps,
cement   machines,   parking
areas   -   everything   needed   by   a   small   town
Their
d
esign
is 
usually 
temporary;   although   their
useful life often extends beyond the period required solely for construction of the dam
The amount of land clearing for the camp is  likely  to be insignificant To the maximum extent possible, trees  should be left standing to provide comfort for the workers  as  well as  supply  a seed
source  once  the  camp  is  decommissioned  If  people  are  to  be  resettled  to  provide  space  for  the camp, the resettlement policy currently followed by The World Bank should be followed
The amount of natural timber harvested for camp construction could be moderately significant if
no precautions are taken Ideally, such timber should corne from the area of reservoir
impoundment Outside that area, its impacts are identical to those of logging destruction of
native vegetation and disturbance to soil and water To the maximum extent possible, the project
should make use of such materials as plastic and metal sheeting, plywood and concrete
The camp electrical powerhouse will create insignificant impacts  to the environment to keep noise to a minimum, the powerhouse should be located away  from residents  and receive regular maintenance
The camp water supply, if it is  a large camp, could create drawdown to levels  below the bottoms of nearby  wells  Affected households  could be compensated by  receiving camp supplies  or by having their wells  rcbored Ideally, nearby  households  should be relocated before the commence mem of construction
Solid waste should be incinerated at a location removed from the camp and nearby households 
The design of sewage facilities should bear in mind whether or not the camp will continue to be
used after its decommissioning If it is to continue in use, then primary sewage treaiment is 
required, otherwise, extensive septic systems might be permissible
/fcrafc  The construction of the Gumero Dam requires  10 km of road improvement Roads  have been shown to be an important contributor to solI erosion, primarily  because they  concentrate and distribute runoff as channel flow rather than as uniform overland or subsurface flow
Access  roads  will be constructed to a high physical standard (compaction, gradient, surface hardness) in order to accommodate the w eight of heavy  equipment As  these roads  are likely  to be used for many  years  following dam construction, the major structures  should be designed to safely  pass  the 25-year flood and the minor structure to safely  pass  the 10-year flood Temporary roads  should be constructed to a permanent standard if their use will continue following completion of the dam or other structure
Because roads are an effective means of access to inaccessible areas, they open areas io increased exploitation logging, farming, hunting High standard roadways should avoid intercepting
TAMS-l’LG Biro-Aki>lK> River Buia lntegrM«l Development Muter Plan
36
Chapirr 3PREFEASIB1LITY STUDIES
v  OLUMe V
i nrrnilwl
hunting areas and locations of exceptional historical
or
— to
control trespassing to these areas are avaiiable
Th, nMigauonr
rise” bed Ltd ditches Cross dram Je should
design     ?   ^
Lon   tu<
desired to
accommodate debris as well as water and sediment
t
o a level below the stream bottom so as not to interfere
Cdvwi oumo
]
slopes              an energy dissipator before
mav require
A  Soil  Erosion  control  Ptnn  should  be  deveioped  du„„s the project design and precede the onset of construction Its purpose is to provide gutdehnes for controlling soil erosion, sedimentation and pollution
The Soil Erosion Control Plan describes the location and type of controls to be implemented It
clearly identifies special resources, such as wetlands and primal forests, that require protection Perceived problems, such as highly erodible soils and unstable slopes, are clearly marked The
plan should contain basic drainage information, such as stream patterns, watershed areas, and the size and iocation of hydraulic structures The erosion control measures should be in accordance
with the following principles
Limit the time and area of exposure The potential for erosion is greatly reduced if the size of the disturbed area is small or its duration short In some instances stabilization can take place as part of construction - it would be wrong to wait until the final grade was established
Retain sediment on the site This pnnciplc is achieved by using devices that filter sediment from runoff or that detain runoff so that heavy particles will settle It includes the use of
materials such as silt fences, straw bales, brush barriers, and sediment traps and basins
Manage only the sediment and runoff from the site. For this discussion we are concerned only with Gumero Dam. not with regional management of runoff and sediment Diversion berms and channels might be required to divert clean runoff around the site
Dam and appurtenant works
Because much of the required fill will come from the reservoir impoundment area, its impact upon the environment is encapsulated within that of the reserv'dr The demand for rockfill (nearly 0.5 MCM) require quames outside the reservoir area Quarry side slopes should be graded to a gentle gradient prior to their decommissioning, the quarry floor should be sloping towards the back cut so that runoff and sediment are impounded Poor to the rainy' season, the quam entrance should be partially closed with a berm in order to retain runoff Upon decommissioning, the quarry should be graded to drain in order to reduce the habitat for mosquitos
With regard to diversion w'orks. spoil from tunnel borings should be removed to a protected site isolated from streams, rivers, and the reservoir
Dislocation qf people The study by ARDCO-GEOSERV (1995) shows that 7 households will be dislocated by the Gumero reservoir. The World Bank resettlement criteria for dislocated
TAMS-t'LG Baro-Akobo River Bairn Integrated Development Master PUD
37PREFEASfBILITY STI DIES
VOLUME V
people should be followed The farmer gross margins for the reservoir area is estimated to be 250
Birr, or USS 40, per year If relocation costs are taken to be equivalent to 3 years revenue plus 
assets (estimated at USS 500), they become USS 620 per household or USS 4,340 for the
households
Lossafjand The reservoir will impound 30 9 km2 The worth of its  standing timber as  dry woody  biomass  has  been estimated in a previous  paragraph The previous  assessment shows  that 7 households  risk  being relocated It is  estimated that upland households  cultivate about 0.5 ha each Each household, on average, aggregates  an estimated gross  margin of about 250 Birr per year from agriculture. thus  the total worth of the lost agriculture (less  assets) is  1750 Birr per year
(USS 280 per year)
Loss   of   historic.   cufiiiralor   aesthetic   features   These   components   were   not   assessed   at   this   level of study but remain for feasibility investigations
of  H  j/dhfe  habitat  The  Gumero  reserv  oir  will  occupy  less  than  5  percent  of  Seie  Mesengo Protected  Area  The  documents  upon  which  this  study  is  based  do  not  quantitatively  describe  the habitat  value  of  this  area  For  this  reason  the  impact  of  the  Gumero  reserv  oir  upon  wildlands  and wildlife   habitat   is   not   assessed   at   this   time   It   is   a   subject   that   will   require   attention   during feasibility studies
Proliferation o f aquatic  weeds During the dry  season, when inflows  are low and drawdown is advanced. the reservoir will become warn and its  dissolved oxygen will deplete it is  likely  that aquatic  growths  will occur It is  not expected that they  proliferate to such an extent that they pose problems to the dam operations or fishery developments.
Deterioration of water quality. Water quality  is  affected when large amounts  of tropical vegetation are flooded by  new reservoirs  The two important parameters  to the process  are the amount of biomass  (estimated as  dry  woody  biomass  between 30 and 50 t per hectare for Gumero) and lhe residence time of the water in the reservoir From a totally  empirical assessment of lhe Gumero Reservoir, it would seem that the short residence time coupled to the small reserv  oir area would place the reservoir out of the severe nsk  category  For the purpose of this prefeasibility  study, it is, however, recommended that the reservoir area be totally  cleared of all biodegradable biomass  In addition, a multilevel outlet should be considered io release w’ater from different levels
Jtewrozr sedimentation The reserv oir will likely accumulate coarse sediments at its inlet and
at principal inlets along its flanks Fine sediments may develop into density currents that will carry 
as far as the dam face, where they will be flushed through the low level outlet Sedimeni
accumulation in the reservoir is estimated to be 516,000 cubic metres per vear Prior to design
a seduneni measurement campaign should be undertaken to confirm the estimate The reservoir
live storage is designed to accommodate a minimum of 50 years of sedimentation
Riverinefisheries The reservoir may  interrupt fish migrations, but this  has  not been directly assessed during the course of this  or previous  studies. A fish ladder and hatchery  should be considered
TAMS-ULG Baro-Akobo River Basin iDtegniced Development Muter Plan
38
Chapter 3PREFEASlBILrn STUDIES
lUlMf y
Water-related diseases At this level of prefeasibility study an assessment of the Gu
reservoir with regard to water-related diseases is speculative, only some indications can be d^0 from outside the project area and, indeed, from outside Ethiopia
raWr
Thp risk  of malaria and other diseases  related to mosquitoes, gnats  midges, and other insect X rs  ttat b-«d or depend upon water (yellow fever, dengue. Onchocerca ) wtll ctattg. ft™  beine seasonal to becomtng perennial The increase will result front improved breeding habitat offered by  the reservoir and its  shoreline vegetation Some of the risks  associated with these diseases can be reduced by controlling wetland vegetation, possibly by recession grazing
Xnti-malarial programs using pesticides such as DDT pose their own set of hazards and costs, and   are   not   recommended   given   that   many   of   these   substances   are   banned   Similarly, chemoprophylaxis is at best suitable only for shon-term, non-unmune visitors to the project area
The development of immunity  and treatment of the population living near the reservoir is, for now, an admittedly  partial solution As  mentioned previously, only  7 households  are thought to live in the reservoir area, so the population density is not high, and their relocation might isolate (he risk
Schistosomiasis  does  not  present  the  same  risk  for  hydroelectric  reservoirs  as  it  does  for  irrigation, which   bnngs   man   into   intimate   contact   with   water   At   Gumero.   the   potential   for   infection   is unknown  given  that  we  have  no  information  about  the  presence  of  Biomphalaria  or  Buhnus Infection  would  affect  people  who  used  the  reservoir  for  recreation  or  as  a  source  of  domestic water  The  greatest  risk  would  be  on  the  lee  shore  of  the  reservoir,  especially  if  vegetation  were allowed  to  accumulate  there  An  obvious  control  is  to  exclude  the  human  population  for  the  shore area,  coupled  with  training  in  hygiene  and  health  If  the  reservoir  were  intended  to  supply  water to nearby households, then water stations removed from the penmeter offer another response
Trypanosomiasis docs not appear to be known high in the upland watersheds, but information about this disease is fragmentary and inconsistent Selkhozpromcxport (1988) reported an
unconfirmed 454 cases in the upper Gilo River, but this is believed to be adjacent to the lowlands Feasibility studies will need to gather information on the frequency of this disease in proximity 
to the site
Selkhozpromexpon (1988) reported the absence of the mosquito earners of Leishmaniasis in the lower basin There is no information about their presence in the vicinity of Gumero reservoir or,
indeed, their continued absence in the lower basin The risk of helminthiasis from hydroelectric 
projects is low as this kind of project does not call for the same kind of intimate contact between
man. soil, and water as does irrigation
Conflicting  demands  for  water  Provisional  minimal  continuous  releases  from  the  Gumero  Dam and  its  in-line  diversions  are  computed  at  8  percent  of  mean  annual  discharge  or  0.70  nA’s. Feasibility studies will be required to evaluate the effectiveness of this discharge to sustain present populations  of  water  organisms  and  competing  water  users  The  present  study  has  not  been provided  with  sufficient  data  to  compute  a  flow  duration  curve  based  on  mean  daily  discharge, from which minimal flow requirements are usually estimated
The  nver  segments  most  at  risk  occur  between  the  dam  and  its  furthest  power  station  The scheme envisions 3 diversions, the first 8 km downstream of the dam. the second 12 km, and the
TAMS-ULG Baro-Akobo Kher Batin Intef rated Development Master Plan
Chapter 3prefeasibility studies
VOLUME V
third   25   km   Each   diversion   take
s
water
from
the
Gumer
o
River
to
feed   i
nto
a
power   canal   I   he
affected   reaches   have   respective
l
engths 
of   3,
2
5   and
6
km.
Th
e
maps 
of
t
hese   diversions   and
their    corresponding    canals    show
no    dw
ellings 
or
roads 
i
n    thei
r
v
icinity.
W
e
conclude,    therefore,
that the risk of conflict is low. subject to the findings of the feasibility study
Increased land pressure The Gumero reservoir will require the relocation of 7 households currently  resident in its  30.9 km2 basin The development is  unlikely  to attract an influx  ot people into the area other than tor the dam construction
3.5 The Recommended Project
J.5J Project Description
fhe   Gumero   Project   storage   dam   is   located   at   the   downstream   end   of   a   tnarshv   area,   up   to   2   km wide   and   nearly   20   km   long,   where   substantial   storage   can   be   developed   without   disturbance   to the   existing   agricultural   development   on   the   hill   lops   above   the   potential   high   pool   level   At   the site   the   drainage   area   is   443   km1     At   high   pool,   elevation   1610,   the   reservoir   has   a   surface   area of   37   km!    and   at   minimum   pool,   elevation   1600,   the   water   area   is   about   13   km'   The   dam   is   35 metres   high   above   the   nver   bed   with   a   crest   elevation   of   1615   It   would   be   of   zoned   rockfill construction with a central impervious core and filters and transition zones
The spillway  is  ungated, 12 metres  long, with a crest at elevation 1610 During passage of the PMF (he maximum surcharge will be 2 m Downstream of the cresi. the chute narrows  to 8 metres  and terminates  in a 25 x  8 x  7 metre deep stilling basin The total length of chute and stilling basin is  120 metres  An outlet channel, which also serves  as  the outlet for the diversion tunnel and outlei works, continues for another 400 metres before returning to the river
The diversion tunnel, which will also serve as  the permanent outlet for power flows, is  3 5 metres in diameter and 600 metres  long The cofferdam, which will diven river Cows  into the tunnel during dam construction, is  of 10 metres  maximum height The gated intake structure and tower will be constructed before diversion and will have slide gates  at 2 levels  for selective withdrawal purposes, and 2 sets  of high pressure slide gates, one service, the other emergency, will be provided just downstream of the selective withdrawal shaft The gates  will be open during diversion For power operation, the service gates  will be closed when changing the opening of the selective withdrawal gates  so the latter can always  be operated under balanced pressure The tunnel discharges  into the spillway  outlet channel, excavated in rock  at this  point, so that a stilling basin is not expected to be required
The first power diversion is  located 9 kilometres  downstream of the dam The diversion weir is an ungated concrete ogee section. 12 metres  long On the right bank  a canal intake structure will be built, equipped with 2-2x3 m sluice gates  Downstream of the intake structure, the canal, sized for 13 nr/s  - the peak  power flow, will generally  have a 7 metre bottom width and a 2 metre depth It is  expected that it will be mostly  excavated in rock  and will be concrete-lined 3-metrc wide access  and maintenance roads  will be provided on both banks  The canal will have a total length of 2600 metres  When more is  known about the topography  and condition of the rock, it
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40
Chapter 3PREFEASIBILITY STUDIES
VOLUME v
I
I
may    prove    advantageous    to    size    the    canal    for    the    mean    daily    power    flow    and    provide    a    re- regulating reservoir at the head of the penstock
The penstock  is  2 0 metres  in diameter and 400 metres  long to develop a total head of 120 metres The maximum plate thickness  is  13 mm At the powerhouse the penstock  will bifurcate to supply 2-61 MW turbine-generators, each turbine will be equipped with one I 00-metre diameter inlet valve, and will have a runner discharge diameter of 0 82 metre The turbine-generator sets  wi|] ntn at a rotational speed of 750 rpm
The powerhouse will include two generating bays  and a service bay  and will be 18 metres  Iona and 9 metres  wide, and the bottom of the draft tube will be approximately  6 metres  below ihe normal minimum tailwater level The two transformers  will be installed on a deck  above the bifurcation, and the switchyard will be located approximately  400 metres  from the powerhouse on a flat area above the flood plain The switchyard will consist of 6 bays  (2 units, 2 lines, I local load and 1 bus  tie) approximately  12 metres  wide by  75 metres  long for a total area of 72 metres by  75 metres  One line will be connected to the upgraded Gore-Gambela transmission line and the other will be connected to Gumero 2 switchyard The existing 66 kV line will be sufficient to cany  the load from Gumero to Gambela when only  Diversion No 1 is  operating As  the other plants, Gumero 2 and 3, come on lint, the existing transmission will require upgrade or replacement to carry  the load in excess  of SO MW For that purpose the connection betw een powet pianists planned to be at 132-kV.
The second power diversion is located 5 km downstream of the first, or a total of 14 km from 1 he
dam The diversion weir, the intake and the canal cross-section would all be similar to Diversion
1, with appropriate modifications due to differences in topography and geology The power canal
would be 2300 metres long leading to a penstock 2 0 metres in diameter and 400 metres long io
develop a total head of 180 metres The maximum plate thickness for this penstock is 15 mm
At the powerhouse lhe penstock will bifurcate to serve 2-9.2 MW units in the powerhouse
The powerhouse will have the approximate same dimensions as Gumero 1, i.e , 18 metres by 9
metres wide The turbine will be proxided with a 1 00 metre diameter inlet valve and will have
a runner with a 0 82 metre discharge diameter The generating set will run at a speed of 750 rpm
The layout of the transformers and switchyard is planned to be similar to that for Gumero 2; the
switchyard will have an overall dimension of 72 metres by 75 metres One bay will connect the
power plant to Gumero 1 and the other to Gumero 3
The third power diversion is  located 15 km downstream of the second. or a total of about 30 km from the dam The diversion weir, the intake and the canal cross-section would ail be similar to Diversion 1, with appropriate modifications  due to differences  in topography  and geology' The power canal would be 6000 metres  long leading to a penstock  2 0 metres  in diameter and 400 metres  long to develop a total head of 205 metres  The maximum plate thickness  for this penstock  is  16 mm At the powerhouse the penstock  will bifurcate to serve 2 - 10.5 MW units in the powerhouse
The powerhouse overall dimension will be 17 metres  long by  8 metres  unde including two generating bays  and one service bay  The turbines  will be provided with an upstream valve 0,9 metre in diameter, and a runner having a 0,75 metre discharge diameter The unit is at a speed
TAMS-ULG Baro-Akobo River Buin Integrated Development Master Plan
41
Chapter 3prefeasibility studies
volume: v
of 1000 rpm The switchyard will consist of 5 bays  (2 units, 1 line. 1 local load and 1 bus  tic) for an overall dimension of 60 metres  by  75 metres  The project will be connected directly  to
Gumero    2
3,5.2 Quantity and Cast Estimate
I    ayouts.    profiles    and    sections    have    been    developed    in    sufficient    detail    (see    Drawings    GU-1    to GU-11)    to    obtain    quantities    appropriate    to    the    prefeasibility    level    Ln    addition    to    major    cost elements   such   as   excavation,   concrete   and   earthfill,   quantities   have   been   computed   for   such   items as formwork, reinforcing steel, drilling and grouting, rock anchors, gates and other items
Unit prices  used to develop the detailed cost estimate are shown on Table 3.10 These were derived from bids  for a similar project subjected to international competitive bidding in Africa and South America and adjusted to a common January 1996 price level
Table 3.10 Unit Prices (January 1996)
Item
Unit
Unit Price
Common Excavation
nT
3.62
Rock Excavation
m?
9 04
Portal Excavation
m
678
Tunnel Excavation
mj
50.84
Borrow Excavation - Common
m7
3.39
Borrow Excavation - Rock
m’
4.80
j Mass Concrete
m’
90.39
Structural Concrete
m'
129 94
Concrete lining (tunnel)
m’
203.38
Formwork
nf
50.85
Steel Reinforcement
T
1.242,90
Unprocessed Fili (placement)
n?
2.26
Processed Fill (placement i
m?
6 78
Filters
m’
16.95
Drains, Transitions
m3
11 30
i Impervious Core
nf
5 65
Drilling (confined space)
m
79 09
Drilling (open space)
m
56 50
Grouting___
T
564 96
Tunnel Support - Rock Bolts
T
6.779
Tunnel Support - Shotcrete
> m
28 25
Tunnel Support - Arches and Ribs
T
2,260
A detailed cost estimate is presented in Appendix 3-1 and summarised in Table 3 11
TA.MS-ULG Biim-Aknho River Bai in Integrated Development Master Plan
ChaptersVOLUME V
CREFEASBItm STUDIES
T.H. 3.11       G.«™ Hydroelectric Pntjeel Cost Estimate (CSS ■ Jammy ( 9%)
Dam& Appurtenant Works                                     — —. rknl Wnrks
________
+
21,780,000
Fnuioment
——
260.000
Powei  Plant  and  Waterways,  No.  1 Civil Works
6,530,000
Fcuioment
6,880,000
Pnw^r Plant and Waterways, No 2
Civil Works
5,850,000
Equipment
9,000,000
Power Plant and Waterways. No. 3
Civil W orks
11,010,000
Eqauirpment ------ ------ ——— —            .. . - - —            > Transmission Lines
9.860.000
4,420.000
Subtotal
75,590.000
Contingencies (20%)
15,120,000
Eng. & Adm (10%)
9.070.000
Total Construction Cost
99,780,000
3.5.3 Implementation Schedule
It is  anticipated that feasibility  studies  and preparation of bid documents  for the Gumero Project would require about 30 months, providing large-scale topographic  mapping and geotechnical exploration could be made promptly  available .Allowing 6 months  for review of the bid documents by the Client and the lending agencies and the bidding process, the construction could start 3 years  after commencement of the feasibility- study  At the same time a decision would be made on phasing of the construction Depending on electric  power demand at the time, and availability  of transmission facilities, it might be decided to build the Gumero storage project, but only  the first Gumero diversion initially, with a consequent reduction in the initial capital requirements  In any  event, it should be anticipated that the construction of the dam (and access road), spillway  and outlet works, along with the power diversion, canal, penstock  and powerhouse would require 2'/i to 3 years, if only  because of lead time required for the outlet gates, penstock  and powerhouse electro-mechanical equipment Thus  it may  be envisioned that first power from this  project could be available about 6 years  after commencement of the feasibility studies, or about January 2005 assuming start of feasibility studies in January 1999
Figure 3.4 shows  the anticipated construction schedule assuming the project is  implemented as a continuous  operation, i e. that the full capacity  of the scheme is  developed at once For that scenario it is  anticipated that the power plants  will come on line at approximately  one year intervals, for an overall construction period of eight vears.
Alternatively, the second and third diversions could be delayed, as previously suggested, to meet the regional power demand With the first power plant commissioned in 2005, the second would
TAMS-ULG Bant-Akobo Rhcr Bum Integrated Development Matter PlanFRKFFASIBILITY STL-DIES
come on line in 2012 and lhe third in 2019 Fiaur? 1 s ch™. , t, .u- L .
VOLUME V
MiripMed demand
3.6 Economic Appraisal
’ ShoWS ’,ow ,h,s sch'dul' "'°uld
The   Gumero   project   will   be   supplying   electric   power   within   the   Baro-Akobo   basin   and   will   be   an alternative to the construction of isolated diesel generators
For the purpose of this  prefeasibility  study, the recommended project has  been ev  aluated in terms of unit cost of generated firm energy  It is  estimated that small diesel plants  generate energy  at a rate of L’S$ 0 07 per kWh Based on the discounted costs  of construction and operation and maintenance, the Gumero project will generate energy at a cost of USS 0 049 per kWh
A   present   value   analysis   of   the   project   was   also   performed   taking   into   account   the   construction costs    and    operation    and    maintenance    costs    For    the    scenario    where    the    three    diversions    are implemented    at    the    same    time    as    the    dam    over    a    five-year    construction    period,    the    economic internal   rate   of   return   (EIRR)   is   14   3%.   When   the   construction   of   Div   ersion   2   is   delayed   and   not commissioned   until   2012   and   similarly   Diversion   3   is   delayed   to   year   2018,   the   EIRR   is   lowered to 11 1%
TAMS-ULG Baro-Akoho River Banin Integrated Development Mmter Pino
44
Chapter 3Peak Power Demand (MW)
Gumero Hydroelectric Project
Implementation to Meet the Local Demand
Figure 3.6PREFEASDHUTY STUDIES
V °LWmV
4.  4.1 i itnatrnodguicrtionrigation project
4.1.1     Project Area
The Itang Irrigation Project, called Itang-Lare in the Russian Master Plan, is  located some 30 km
west   of   Gambela   on   the   nght   bank,   north   of   the   Baro   River,   between   approximate   elevations   415
and 430 metres  above sea level, and approximately  between co-ordinates  33°5711 - 34°21 ’E and
8 <WN-8°27 N
r
The    area    is    north    of    the    Gambela    National    Park    Administratively,    the    project
area    is    in    the    Gambela   region,   Itang   and   Jikawo   weredas   The   project   location   is   shown   on Drawing No IT-1
The project area is  a fiat plain Its  average slope is  about 0.0005. Most of the area is  covered by open woodland, grassland, including mostly  bushes  and shrubs  The area is  limited by  the Baro River to the south, some hilly  areas  with elevation of up to 500 m to the north, the Jikawo River to the north, flat flood prone areas  to the west and mild sloping terrain with some localised rock outcrops  with peaks  exceeding 500 m elevation to the east The lower (southern) part of the area along the Baro River banks  is  subject to flooding Flood water levels  elevations  along the Bare vary from 415 m in its lower (western) extremity and 429 m in its upper (eastern) extremity.
The area is  traversed by  the Gambela-Kurgcn road This  is  an all-weather road The road is  to be upgraded and extended to Jikawo. A short, approximately  5 km- long, spur links  this  road to Itang
The only town in the ptoject area is Itang the population of which is estimated at 2300
Population on the lung and Jikawo weredas and on the Gambela wereda are estimated at 22.053,
43.685 and 30,115, respectively. Population growth in the area from 1984 to 1993 is estimated
to have been over 7% per year .Most of the population is rural
Electric  power is  mostly  lacking Itang is  served by  a small mobile diesel plant The nearest power transmission line is  the 66 kV Sor-Gambela-Dembidolo line served by  the 5 MW Sor hydropower plant EELPA is  studying the possibility  of linking this  line to its  interconnected system
Potable     water     supply     and     sanitation     are     practically     non-existent     The     Gambela     Regional Government is presently building a groundwater based (deep well) wuter supply project at Itang.
Small scale flood recessmn agriculture is  practised along (he banks  of the Baro River m the vicinity  of the project area In the region at large, livestock  is  a major economic  activity  Some dry farming is also present upstream in Gambela
TAMS-CLG Bar^Akobo River Buh Integrated Development Mailer Plan
4$
Chapter 4PREFEASIBILITY STL
dies
VOLUM
E V
4.1.2      Institution al Setting
The    Ministry    of    Water
Resource
s 
is 
rhe
natio
nal
institution
respon
sible
for
larg
e    scale
irrigati
on
projects     and     tor     count
rywide
w
ater
po
licy,,
dev
elopment
and
manag
emen
t
The     Mini
stry 
of
Agriculture has nation-wide responsibility for agriculture
At   ihe   regional   and   local   levels,   the   regional   and   local   bureaux   bear   responsibility   for   day-to-day management and implementation ol water and agriculture policies, development and services
Specific    large    project    development,    such    as    on    the    ongoing    Alwero    irrigation    project,    is    the responsibility of an ad hoc project office
Ihe Baro-Akobo Master Plan has  analysed the present institutional setting and made several proposals  for the development of the Baro-Akobo River Basin One of them is  the creation of a River Basin authority  Details  on the analysis  made and the proposed measures  are given in the Master Plan report and m its institutional Support Annex 3G
4.2. Basic Data
4.2.1 Topography
Various topographic data are available in the project area This includes (he following
Maps at 1/50,000 scale with contour intervals every 10 m and interpolations every 5 m
These include the following maps Rang. Larc. Jikawo, Birhane Selam and Shenkwar
Mountain for the irrigable area and hang and Sefera Tabiya for the [tang reservoir area
These maps were produced in the former USSR for the Ethiopian Water Resources 
Development Authority in 1985 and are based on aerial photography taken in 1983.
* Topography  at 1 /I0,000 scale of a representative plot covering a gross  area of about 1800 ha. The map has  1 m contours  and interpolations  every  0,5 m_ This  map was  prepared by Selkhozpromexport in 1988-89
A   topographic   map   of   the   [tang   dam   area   of   1/10,000   scale   with   contours   every   2.5   m   and interpolations   every   1   25   m   The   available   map   is   a   reduction   at   1/5,000   scale   and   covers an  approximate  surface  area  of  5.5  km  x  2  4  km  or  13  75  sq  km  This  map  was  prepared by Selkhozpromexport in 1988-89.
4.2.2      Climatic Data
Genera!
Climatic  data is  available for rainfall, temperature, wind velocities, relative humidity, hours  of sunshine, evapotranspiration and evaporation The source of this  data is  the National Meteorological Services  Agency  (NMSA). Data was  obtained through the previous  studies  and to some extent directly from the NMSA
1
TA MS-L LG B^m-Akobo River Bai In Integrated Development Master Plan
46
Chapter^■          --          --““          "          "          “          ~          “          “• ^nper.ture of*!* coldest month is greater than 18 C
the  project  area  is  located  at  Itang  Stations  in  the  vicinity  of  the rraect  area,  in  the  Gambela  Plain,  include  Pokwo,  Jikawo  and  Gambela,  all  located  within  about 30 km distance Elevations at these 4 stations, in metres above sea level, are 415, 425. 410 and 440. respectively Abobo. located about 70 km south of the project area is at elevation 455 mas!
\kndtlv  rainfell records  tn  and near the  project area, during  the  penod  of 1952 through 1992, arc as follows:
Itang 114 months from 1973 to 1982 and 6 months in 1985, or a total of 120 months 
Pokwo 15 months from 1956 to 1957, 10 months in 1959, 94 months between 1961 and 1967.
55 months between 1975 and 1980 and 41 months between 1983 and 1987, or a total of 215
months
Jikiwo A total of 80 months, during the 1973-1979 period
Gambela  A  total  of  80  months  during  the  19771  -1988  period  In  addition,  there  is  historical data dating back to 1906
In the Master Plan studies, long-term synthetic senes were produced, including a 34-year senes (1956-89) for all 4 stations
)
The resulting long-term mean values, in nun per month, are given in Table 4.1, below
Table 4.1 Long-term Rainfall (mm)
Simon
1
-------- - ------------ ’ 5 king11)
Jan        Feb       Mar     Apr       May      June       Juh
Sept         On          No»         Pc<
1.0          5.7
12 3
47 4       137.0      1008
172.7
1344       105.0       ioao
6 Polwo(l)
4.0
24.5
461
116.7
324 7
170.1
2151     ' 1543         1226
59 5
42 8
8JiUwo(2)
26
9.2
40,0
127-2       910       159.6
1707
122.0
67.0
4.0             2.9^
4 Gambela (1)
32
45       26 5
49 9       1403
148 4
2159
194.9
164 4
94 $
30 1
4 GambeU (3)
66
102      332
739        154.5
169 8
2290
248 6
179 1
113.0       47
4 Gambell (4)
0
2          12        31       r 124         124
145
166         112
—
61             179
i 4 Gambela (5)
=2—
0               20         39         116         86
!*
149 76 20
-
93j^ J2^
~ 0 J.
(I) 195WMJ.Q)                      O)
(4)  MSithibtluy. HM-im^SJIOSrU^ IJ56-1W9
The above dearly indicates a rainy penod between May and October and a drv penod between November and Apnl The resulting distribution during the drv and wet seasons as defined above, in percent of total amount, is given in Table 4 2, below
TAMS-VLG B.nvAkobn River Buin ^•etopBe’.r^P|ln
47
CbiP«er4PREFEAS1BILTTY STUDIES
VOLUME V
Table 4.2 Seasonal Rainfall Distribution
% Distribution
Dry
Wet
1Jtang
Pokwo
Jikawo
Gambela
The    annual    rainfall    vanes    considerably    A    comparison    for    the    above    long-term    period    is    given in Table 4.3, below
Table 4.3 Annual Rainfall Variation (mm)
(1956-1989)
14
86
(1956-1989)
12
88
(1973-19891
8
92
(1956-1989)
II
89
Itang
Pokwo
Jikawo                       Gambela
Maximum                      2504 0                            1405 6
1092 3
1514 0
___
Minimum
Average                        885 1                              1031 8
796.6
1082 7
185.2
654 8
544.3
642 7
Maximum   daily   (24   hr)   participation   data   is   available   at   Pokwo.   A   statistical   analysis   shows   the following results in millimetres
Mai. 24-Hour Rainfall (mm)
1 /20 year            115
l/l0 year               102
Temperature
Temperature   data   is   available   at   Gambela   (Station   4)   and   Itang   i   Station   5)   at   elevations   440   and 415 masl, respectively
Minimum temperatures  have been observed during 123 months  al Gambela, 157 months  at Itang and 72 months  at Jikawo during the period from 1973-75 to 1985-88 Maximum temperatures have been observed for 73 months  at Gambela during 1980-1988 and for 134 months  at hang during 1973 -1988 and 71 months  at Jikawo during 1975-1985 Existing gaps  have been infilled as  discussed in the Master Plan Annex  1A After infilling these gaps, a synthetic  record has  been produced during the Master Plan studies. The resulting maxima and minima monthly  and annual temperatures in *C arc given in Table 4.4, below
TAMS-l LG Bam.Akobo River Buin Integrated Development Mai ter Plan
48
Chapter 4PRE FEASIBILITY STUDIES
volume
Table 4.4
Average Maiimum and Minimum Temperatures (°C)
—- ------
Jan        Frb        Mw jApr
Jme        JuR         Aop        Sepi          Oct           Not        Dec
C-ianbdifSu4)
1________
I
1 Aw SUx(l)
U | )9 1
40 J |
40.8 1
401
36 0
326
32.3
324
32.5
34.1
34$
366
Aver Mm-31
16.4 I
1»J
20 3
31.8
19.9
382
173
17 t
18 1
17.8
17.9
16 9
lianjti Su 51
|
Aver Max (2)
369
J4? |
IS 3
38 1
34 9
33 5
32.7
32 1
312
34.6
34.9
35 3
Aw Mm(2|
19.5
20 5
20 K
210
i 175
17.0
36.8
17.0
17.7
20,2
IS 3
18 7
Jtofl ($ti >)
Aw Mm (1)
35 6
1  379
3S 1
38 3
34.7
32 6
31 1
304
31 3
33 3
33 7 “
346
Aver. Moi (4)
112
193
19.1
21 6
21.1
21 1
214
JU
22 0
21 7
20 4
176
(1) 1VMI- LWB>; <2) 1J?> I9U. (J) ! 9*4-198*; (4» 1975-1988
5W
Wind speed has been measured at Gambela during 10 years from 1976 to 1985 The average monthly wind speed in m/s is given in Table 4 5, below
Table 4.5 Average Wind Speed (m/s)
January
5.2
July
5.2
February
5.9
August
71
March                                    5.9
September
63
April                                       6 3
October
6.0
May                                       83
November
5.4
June
|~5.4
December
74
The above shows a very homogeneous distribution throughout rhe year
The maximum and the minimum average annual wind velocities observed have ranged between 20.17 m/s in 1985 and 3 50 m/s in 1977.
Relative Humidity
Relative humidity has been recorded at 12 00 noon al Gambela during 13 years from 1974 to 1986
The mean monthly data, in %, are given in Table 4.6, below
TAMS-t'LG BaroAkobu River Baiin Initialed D^rlopment Mailer Plan
49
Chapter 4pRJlFEASIBn-m STUDIES
VOLUME V
Table 4.6 Relative Humidity (%)
1am i a TV
61,5
July
80.8
c j-spi r I i a rv
, 
IVicirr'h
58.5
August
80 8
J. ■ ' 1 kill 1 8                 __ .. —
A nril
rvpj 11 
Xiav
_----------
■ ]|jUT
—---
June
57.7
64 6
76 9
78 5
September
79 2
October                                  73 1
November                              66 9
December                              63.1
The    average    annual    relative    humidity    observed    during    the    above    period    ranged    from    67.5%    to 73.3%
Hours of Surishitie
The   hours   of   sunshine   have   been   measured   at   Gambela   during   the   13-year   penod   from   1975   to 1987 The average monthly records, expressed in hours per day, are given in Table 4 7, below
Table 4.7 Hours of Sunshine Per Day
January
7 00
July
431
February
7.77
August
5.15
March
6 16
September                               5.77
April
6.38
October
6 62
May
5.23
November
6.92
June
4.91
December
j 7.38
The    lowest    values    correspond    to    the    rainy    season    The    average    annual    values    recorded    varied from 5.42 to 6.83.
Available mean monthly  and total annual data on potential evapotranspiration ( PET) and lake evaporation (LE) is  available from records  at the Gambela, Pokwo and Jikawo Stations  The data, including mean monthly  and mean annual values, expressed in mm are given in Table 4.8, below
Table 4.8 Potential Evapotranspiration and Lake Evaporation (mm)
Feb          Mar          *pr            Mm           Junr          July           Au*            StRt           Oct              Nov           Dre          Tomi
Gambtia
1
PET                         116         140     | 176           161           130           133           107           113            116            124            120
. 
Ajincud
125                      U6I 0
L£
Pukwij
PET
LE
JiiuTHu
1 95!         M           123         113       ^’1          79 1          74.9          79.1           81 2            868              84       ! (7.5            1092.7
1
127        L 18        172         162       1 134
SS9 96.6 I 120 1 ID 93 8
1
113           1W           107            118
79 1          76 3          74 9
f26
127             118           123        1 D«
889 82,6 36.1 3083.6
' PET                         112        109     | !49        1 132             115          S3            AS            97              110            IQS
410       1 99               1637
LE
7*3         104        l0t>           803          61 6          616           67 9          77              75 6            2*7        1 69 J           11459
TaMS-VLG B uro-A kobo River Butin Integrated Development Mailer Plan
Chapter 4
50volume v
prefeasibility STUDIES
12.3 Hydrology
There are 2 hydrometnc• s,at^
• >h. inw*r Raro River The closes! one is at llano tl
drainage areas at these ^ons are 24
je 66
^^be,a sla^ '
ns*
rc tive v
|  Data at Gambela is available since 1906 In more recent
196710 1993 a"d atIUngfr°m 1974 l° 1993
Several gaps exist in the available flow records These gaps have been infilled as desenbed in Annex IB of the Master Plan Report
The mean monthly and annual flows are given in Table 4 9. below
Table 4.9 Mean. Monthly and Annual Flows
-- ----- -v
Jm               Feb
Mar       Apr
Mar
Jnnr
July             Aa*
Kept
Orc
Nov
Dec
Annual
m i
r^Lnl
80S
215 6
SIB
127 h
42 J         *03 1110        ] 563
133.D d 374.0
35*3 949 3
67S4         905.9
1 Bl 7.0 1426 3
!0S9 1
2745 2
1949.5
295-9
767.0
139 ?
3737
—J1                                 1
1 IE3.'J
I fDCT
112        1 74 2          612          IM        I l$Xl      I 37*7
3005 1 LT? 5 L1665 ID*
■*,_ —u_
MOO    I 976.5
664j 9018 1039.7 775.3
1779.0 2418.0 2695 & 20765
r  ails’1 8125
1594
427.0
"395? = 124395
About 85% of the annual flow at Gambela and 83% of the annual flow at ltang occurs  during the flood season of May  to October The remainder. 15% at Gambela and 17% at Itang. occurs during the low flow season from November to April The lowest flow is in March
Annual   flows   vary   considerably   The   maximum,   average   and   minimum   flows   recorded   are   given in Table 4 10, below
Table 4.10 Annual Flow Variation
,
T
Max
Aver
Min
Ratto MaxZMin
Gambela !l?
menvyr                                  15.780 0
12.0160                       7.470.0
2 11
m7s
500 4                          381 0
236 9
Itang m
memyr
15.850.0
12,459 5
9,080.0
1 75
m'/s
502 6
395 1
298 9
HJ mtn iru*
_ —-
fl) 1974-1903
A detailed analysis is found in .Annex IB of the Master Plan
Flood flows are discussed in Annex IC of the Master Plan
Hood water levels  were estimated in the Russian studies  at the gauging stations  and at the dam site locations  Data at the project area and nearby  upstream and downstream of the area arc given in Table 4 1 lr below
TAMS-ULG Baro- A kobo Rh e r Batin Integrated Development Matter Pte®
51
Chapter JPREFEASIBILITY studies
VOLUME V
Table 4.11 Maximum Instantaneous Water Level Elevations (masl)
Return Period
Gambela
hang Dam Site         Itang Station
Jikawo Station
i vears I
y       _z—-——------ 1/10000
1                                           Station
436 36
429.60
424 65
410.38
1/1000
43603
429.50
424.52
410.32
1/200
435 76                          429 30
424.44
410 26
1X100                            435 64                          429 20
424.38
410 23
1 20
435.31
428.85                          424.25
410 15
1/10
435.14
428 70
424.18                            410 I I
4.2.4 Sediment Data
Suspended sediment data is  scarce and unreliable A discussion is  given in Annex  IF of the Master Plan Report For the purpose of planning the reservoir operation studies  performed for this  prefeasibility  study, an average annual volume of 13,560,000 m' has  been estimated to accumulate in the reservoir
4.2 5 Wafer Qu ality for Irrigation
Although data on water quality  for irrigation is  scarce, some data on water sampling and chemical analyses  are presented in the Russian Master Plan Report, Volume III. Annex  1, Climatology  and Hydrology
This   includes   the   results   from   analyses   of   51   samples   taken   al   various   locations   within   the   Baro River Basin during 1986-1988,
The   number   of   samples   taken,   and   for   which   chemical   analyses   were   reported,   include   4   samples at hang, 13 al Gambela, 6 at Bonga and 1 at TAMS4 site
The water quality data for irrigation can be summarised as follows
Residua] sodium Electrical conductivity 
* Sodium Adsorption Ratio
< 1.25 m equiv.'litre
< 0.20 mhos, cm varies from 0.12 to 0.36
1
Based on Electrical Conductivity  (EC) and Sodium Adsorption Ratio (SAR), according to the USDA classification (Riverside), the water quality  for irrigation can be classified as  C 1-Sl This reads as follow s.
Cl = Low Salinity Hazard (EC<250 rnhos/cm.)
SI = Low  Sodium (Alkali) Hazard (SAR<10)
The above means that:
Water quality for irrigation is excellent
No reduction in crop yield is anticipated due to water quality.
TAMS-L LGBaro-Akoho River Ruin Integrated Development Master Plan
52
Chapter JPREFEASlBII-in STUDIES
4 26 Land Resources
Lmi
rowers      were      in      the      current      Plan      based      or.data      pven      tn      rhe      proMu,
studies by Selkhozpromexport earned out in the 1980s and published in 19
In the Master Plan land suitability  evaluation, part of the area was  assessed as  suitable and pan of the area was  assessed as  moderately  suitable for diversified crops  It was  also found to be suitable or moderately suitable for rice
Soils in the area have been studied and mapped by the Russians at 1/250,000 scale Subsequently, a combined map of the entire basin grouping the Russian map for the Lower Basin and the ARDCO-GFOSERV map on 1/200,000 scale for the Upper Basin was  carried out in the Master Plan studies and presented at I '1.000.000 scale (see Master Plan Volume 4) At this time the soil types  were reviewed and grouped This  resulted in less  soils  types  than the original Russian classification.
The  soils  types  present  in  the  project  area,  according  to  the  present  Master  Plan,  and  the approximate distribution in percentage of the total area are as follows
Soils Description
Gass
% of Project
Area
4
Distnc and Chromic Cambisols weathered and often shallow with 27
coarse topsoil
5
Entric Vertisols seasonally waterlogged generally fertile often flooded
59
in lower basin, risk of sodic conditions
9
Dystric and Entric Fluvisols. variable textures, usually deep Slight
11
erosion hazard
10
Eutric Glevsols, seasonally waterlogged Low erosion hazard
1
11 
Dystric and Eutric Piinthosols. variable textures, usually deep. Slight
2
erosion hazard
For their soils  survey, the Russians made a number of test pits and auger holes In addition, samples were taken from the test pits a< various depths and tests were made in the laboratory.
The laboratory tests on the soils samples included moisture contents and grain size (gradations) Data from 10 pits in and around the project area, including 50 samples, were found Pits were
up to 2 m deep About $0% of the pits and samples are located within the project area and the remainder are located in the vicinity of the project area No data on the auger holes was found
The results of laboratory tests from test pit samples are given on Table 4.12.
A 1 250,000 scale soil suitability and land reclamation classification map prepared by the Russians is available It contains VI major classes and 3 sub-classes (a, b. c).
T AMS-ULG B.rn-Akobo River Buin inte.ratrd Development Muter Plan
Chapter4pREFEASIBILITV STUDIES
The land is classified according to the following classes
V OLUME V
Class I Class 11 Class III
Class TV Class V Class VI
Lands     not     requiring     fundamental     reclamation     measures     and     special engineering works
Lands    not    requiring    fundamental    reclamation    measures    but    with    certain limitations in their agricultural use
Lands      needing      runoff      control      and      improvement      of      hydrophysical properties
Lands needing flood protection
Lands needing flood protection and drainage Lands unadvisable for agricultural development
The   main   classes   in   the   project   are   If,   III   and   V  There VI
are also small areas in Class 1 and in Class
TAMS-ULG Baro-Akobo River
Basin Integrated Development Master Plan
54
Chapter Iprefeasbiuty studies
Table 4.12
hang Irrigation Frojed  »
pit        Sample         Hvfcro-
No* dePth cm moisty*—
1687      0-16                137.173
S   ils Sampl" L’b“r,",r’ Tf«*
Soil Fraction^-jSize in mm _
0.05-0.01 0.01 -0.005 Q.OTS-0.00]
"2L52         39 50            |  1231
9 36_
5 25
17-27
J8-48 Z 70-80 180-190
1585     0-20
3040
80-90
163
6 95 _l 604
6_5O_
20 44        40.39               7.27             1 7 76                 3.49                - Jo is
20 60        22 30              6 53                6 27                  6 95 20 47     1 22 84               5'3                  092                   14 52
37 3$’
35 52
17.94      29 49            3 67
2.70                  11 52                   34 68
9 20__         370          4 4                  4 80
9 7(|
30.80
_ 46.60
JW0
: 5C          1 40
3.50                7 50                   13 90                   ‘ 16
970_            2 90           1080              690
4.1c                  10.40                   64 80
14U-150        12 60 190-200  127O_
156£ JW2 _ _660 ___________ ' 25-35 6 30
50-60              8.00 7M0            1 _800_
! 50          1.10
10.60               10.90
74 70
2.50           100                3 40                 1813             1 11 80                1 79.50 1
‘ 4 30          ! 2180           | 11 00               3.10
3ty           18 20
2 20
' 14 40
13.50
45 50 ‘ 4900
380 | 1300 9 30 580 12.70 55.30
2 80 1 18.70 14 50 0.60 16 00 47 40
H0-120       J80______  1 260          12 00              12.50              440                  870                      59 80
170-180        7J0
4 10          9.00             | 10.90              460               1 12 40                   58 90
1S72_ _O’29_ 35-45 70-80
« -lin
4 00 IJ .00
620 ’ 6.40
1 8.60          20.00           Hl 50
18.80              890
32.40
780 , 1260 7.20 10.30 19.10 43 00
6.50        ' 23 60           | 070                  8 80                1S.90                  44 50
4 70
11.00             5 JO
7 70                  57 50
’240
704:
150-160        880
18C-190
1568     0-24
24-49
49-90
_ 111 _  _
I 917
7.80
661
4 10         10.10              3 60                6 80                10 30                  67 20 490          7 50                980                 4.60                12 50                  61 10
1 13 58              7.48                7 97                 1583                   5123
3 95         1.95                G82                12.50              1564                   65.14
2 77         6 34                1.57               3.01                15.83                  70,48
90-123
123-70 '
ljO25
2 49
' 6 01
4 76
5 52
"IL32
69 80
_J0.74
2 88
096
8 35
1 300
’12 17
72.74
170-200  JIJ3
2.22
_ 7 00
5.50
' 7 27 ‘
J J100'
9 19
i "1 82
1594     0-y 
2.00
0.90
17 30
” 49 40
40 -SO
13 60
10.20'
20.30
1 10
060
630
4 00
17.90
7010
____ *l*L_l!26C
1 60
6 20
5.60
450
9 10
73 IO 1
150-160         1440
167£_ 0-24   J 88,
. J- 80
1 iTTV
_2p SH 1 /z
16.60 ‘
- - 4>i5_                   4 70            8 60_  ,26.IF’ ?5-105_        4 38            9,12 ZjZO
15QJ6G4.60                          6 98        ' 6223
1566  0-17
30-40
41-71
, 33.90 17.28 .
8 10         68 70~ ’
. I860 ,16.70 '14.50
10.28           | 9.41
' 1234              25 64
2 30 _                    2.80                     890
8040
JL90
1 8 30
1 17J0_'
144 15
ULso
790
14.40 .
1682 ’o-l<
25-36
50-60
060‘
t ] 40 ’
480
11.55
27 97
21 37
8 20
24 74
14.97
70-80
14 53
12 25
25.30. _
,_O4i
2 7C
8 46
‘_0 28
Lui
j 2.99
n 60 _. _4 70 uo~----------------------- ^ - -
0
— 3«L _
n?_o_ .14.90' Tino--------------------- £ J —
J4 5O
850
17 30 ~ 9'80
___ -lfo— - -
_ ioouio. Imo _ 4»- a ic’ - - tf?o- '
23'
Source Selkhozpmmcxpori Mas-.cr Plan Report,; 996 TAMS-ULC B.n.AkoboRiver B^tah,^
--- ------
980 i 11 40 _8.70 ’ ‘ 10 80 A7G ~~ >10
25.00 L 66 40 _ 52 20 62.80 67.70.
Chapter 4
55prefeasibility studies
VOLUME V
The total gross area within the boundaries of Lhe project area defined by the main canal, the Baro
River and a western limit based on avoiding most flooded areas, covers approximately 72,500 ha
The central portion covering approximately 8000 ha is a flat area difficult to drain This area,
which needs to be carefully studied, has been excluded from the farming area and could eilher be
used for other purposes in the agricultural development or partlv farmed if future studies 
determine so The remaining area covers a gross surface area of 64,500 ha.
In    addition,    villages    and    other    unusable    areas,    covering    approximately    5500    ha,    have    been excluded   The   remaining   gross   area   is   estimated   at   59.052   ha   For   the   purpose   of   this   report this   will   be   called   the   usable   area   The   net   irrigable   area,   after   deduction   of   the   irrigation   and drainage   systems   and   related   roads,   has   been   taken   ai   90%   of   the   usable   area   The   net   irrigable area   has   been   estimated   at   53.147   ha.   which   is   slightly   in   excess   of   the   area   anticipated   al   the planning stage
4.2. 7 Geology and Geotechnical
The Russians  produced a geological map of the region at 1Z250,000 scale This  Master Plan has produced a regional geology' map at 1/1,000.000 There is  no other geological map for the Itang dam or the rest of the project area A geological cross  section 08-12 was  made by  the Russians along the axis  of the proposed hang dam This  section shows  the site to be in lacusinne-alluvial deposits of clays and loams overlying intrusive trachytes and syenites at depth
The dam site is  not covered by  aerial photographs, but aerial photos  are available both upstream and downstream of the dam she and at ihe irrigable areas  Aerial photographs  are about 1/70,000 scale and the quality  is  not good In addition, they  are over 20 years  old More recent photographs  used for the 1/50,000 scale topographic  mapping were not made available Five drill holes  by  the Russians  are shown on the geological cross  section However, the logs, site and laboratory tests, cores, and report on the site investigations were not available for this report
Some test pits  were made by  the Russians  along (he main canal, some distributaries  and some major drains  Only  a brief description is  available There is  no data on sampling or on field or laboratory tests
There is no information on construction materials for embankments, riprap, and aggregates
Apparently   the   area   is   not   seismically   active   and   presents   a   low   seismic   risk.   However.   no   data on seismic activity in the vicinity of the project area is available
4.1 Project Development
< 3. / Agriculture and Cropping Patterm
Diversified agriculture is  possible in the project area The climate, water and soil lend themselves to a variety  of crops, including cereals, pulses, oil crops, fruits  and vegetables, sugar cane, fodder and cotton.
TAMS-ULG Biru-Akobo River Buin
Development M«ter PUn
56
Chapter 4PREFEASIBILITY STUDIES
volume V
In  order  to  develop  agriculture,  the  lower  areas  need  protection  agatnst  flooding  There  is  also need for an adequate drainage system to prevent water logging in pari of the project area
A  diversified  cropping  pattern  suitable  for  the  project  was  prepared  which  includes  food  crops pulses,  oil  crops,  vegetables,  cotton,  and  fodder  (green  manure)  The  proposed  cropping  intensity is 166%
The  crop  distribution  of  this  cropping  pattern  in  percentage  of  the  area,  for  the  dry  and  wet seasons, is given in Table 4 13. below
Table 4.13 Diversified Cropping Pattern
Crop
% Area
Dry Season
Wet Season
Cotton
25 
is
Maize                                                                                               40                                    15
Sorchum
19
10
So\ Bean
10
10
Vegetables                                                                                        1                                      1
-J
Fodder (green manure)
50
Groundnuts (peanutsVoil crops
0
15
Sub-total                                                                                        100                                   66
Total Cropping Intensity
166%
This could be cultivated by small holders or small holder co-operatives as well as eventually by medium size farms Although the size of the farms has not been determined, small holders mav have anywhere between 2 and 5 hectares Medium size farms could have say 5 to 10 ha Co operatives may have 20 ha or more.
Food produced would have a ready  market in Ethiopia Some quality  cash crops  may  be eventually exportable Commodities such as cotton may be for the local market but may also be exportable
These crops can generate a number of agro-industrics, such as oil extraction plants from maize, soy  beans, cotton gm, soap plant from cotton seeds, peanut-based industries  Fodder would be for feeding the livestock Gram can also be used to develop poultry farms, although grain may need mixing with other poultry foods
Sugar cane looks like a promising crop, thus, it is also being proposed for this project The
economical size of a sugar plant is estimated at 7000 ha Three such modules are envisaged
Thus the total area in sugar cane would ultimately reach 21,000 ha for 3 modules These would essentially be commercial ventures However, a good portion of the area may be grown by small holders or co-operatives under contract with the commercial venture enterprises
Sugar cane would supply  an important regional industry  for production of sugar and possibly derivatives Molasses, a by-product, can also be used in several ways, such as to produce ethanol or as animal feed as part of a mix. Bagasse is also usable in various ways
TAMS-t LG Baro-Akobo River Basin Integrated Development Master Plan
57
Chapter 4PREFEASlBlLm' STUDIES
VOLUME V
In summary. 21.000 ha of the total 53,147 net area would be ni
a■
balance, or 32.14? ha, may be developed for a divewifi^   ,
P
d 111 su8ar cane while the
above
^culture onentation as described
/J. 2 Irrigation Water Requirements
The irrigation water requirements for the diversified crn™
Master Plan studies  These estimates  were based on thP /7?^ panerT1 were estimated in the crops  in the cropping pattern, for both wet and dry  season? Th rcquiremcnts of individual were determined by  subtracting the 80% reliability  momhlv  / T im^tl0n waIer ■ ^irenients requirements  of the crops  in question The gross  monthlv  * eClne rajn^ from the field obtained by  dividing the monthly  net water requirements  hv  th^ ° n .reqiJirsm<nts were
'T"“’'ffiOCTCy Thc
s "MU, Uismounon and conveyance efficiencies TahU j 13
latter was taken a. 50%. including field dSZtd^
presents the water requrrenrents calculation for the diversified croppmg part™
For this particular project, the weighted averacw
.
requirements  have considered the mix  of sugar cane and th SS m°nlhJy irrigation calculation assumes  21,000 ha or 40% planted in suaar can a it mi croppin^ pattcrn The
d,versified rotat.on Overall irrigation SoesXTZ’at X and 60% for the commercial sugar cane o£X“ £ that described above for the dieted X“"s p^S^^X^T “
’T’
d 'V'rS""d ,°U,I°"
TAMS-ULC B.ro-.Akobo River Baiin In^rMcd D*vekPmfn‘ Mijler P,*r
58
Chapter JTable 4.14 |lm( Irrigation Prujer! MgMM W»«r Requlremen.. - Typie.l Cropping P,iiern (Divined)
Rainfall
Jan
0
Feb
0
March
8
April
25
Mav
100
.lune
118
42 5
Job
145
87 5
Aug
166 45 40
Sept
110
125 120
Oct
55
Nov
15
Dec
0
Field Water Requirements     nun WEI SEASON
Colton 25%
1
Maize 40%
Sot gliuni 19% Soy Bcan^ 10% Vegetables 1% (been Ma nine 5%
—
■                     25 40
1 000          128
4
■ —* —
17 1 ___       49 4                  19
5
15
20
13 3
15 80
0.4                0 6
1 5                0.8
—
20
2 0              0 16 5           28
Annual
932
212 5 320 0
98 8
65 0
3 3
31 5
-
5
0                 92 5            216 0
85
;*
Subtotal 100% 0 0 0
DRY SEASON
H
267 0
7 
171  1 Z 1. 1 1 _
r
0 731 I
57 8 140 3
Colton 15%
Maize 15%
Sorghum 10% Groundnuts 15% Vegetables 1%
So; fkan 10%
Subtotal 66%
1 olal Crop Intensity 166% Field Water Requirements
29 7 46 2
77
8 I 198
-
32 5
--------
165                    413
8 3
13.2
22
99           22
176
132 1 572
--------- —
6 6                23 1                   85 9
..J
___
23 7
24 8              182
0.7                0.6
16.5                88
125 6              557
1216” 557 23 7 0
0000
0
—
—
------- --------- 0
04 5 5
32 3
0 7 16.5
90 i
12 22 0
163 0
3.6 71 5
490 6
________
—
92 5            216 0
267 0
122 0
____ 1 121.1                325
34.3            90 3                  163 0              1221.7
Nel Irrigation Requirement s(2)
•mm
125 6
55.7            ”il7                  0                   0                 98 0                                                                                          0               75 3                 163 0                 655 3
1220
•m1 2 3.ha                            1256               557               157                  0                   0               980                                                                                              0            753 Gross Im gal ion Requirements (3)
00
00
1630                 6553
m'/hn 
-l/sflu
J 2512               1114              314                   0                   0
1960              2440                    0                    0
0            1506
3260
13106
__0 94
0 46             0 12              0                   0
0 76                 0.91               0                    0                       0                  0 58
1 22                    042
1) Effective ramfall, 80% reliability, based on approximately Ml years of records al Gambeln Aimu.il means total annual
2)   Field Water requnemcnts minus effective rainfall
3)   For 50% irrigation efficiency, including field, distribution and conveyance losses and wasteTable 4-15 Hang irrigation Project For Sugar Cane • Diversified Rotation Mix (2)
1—
1 J J It clivc Rainfall in irun. (I)
Jan
Feb
March
April
May
June
July
A«K 1
Sept
Oct
No*
Dec
Annual
l
0
0
8
i 25
1
too
118
145
166
110
55
■
0
932
1 Held Wider Requirements -
1
)
i' Sugar cane - nim
1 120           ' 120              110             110            100           100           100               100            110                I2t)              130              140                       1360
1 Nel Irrigation Requirements-                12<J       1 120          1 102                85                0             0                0                    0                0                  65             115              140                         747
Sugarcane - mm
Gross Waler Rcuuircinenis - Sugar cane
for 60% efficiency                                 200             200 Gruss Rcquiicincnls
1
170
142 0 0
-
.............. _J 0 0
0                108             192
1
233 1245
Diversified Cropping 1‘cn 50% efficiency (3) (iiass Requirements
Weighted Average
- mm (? )
1
251.2          1114             314              0                0           196           244 0
0
0
0
150.6            326.0
1310.6
230.7          146 «            868            56 8             0
117 6        146 4                0                0              43.2          167 2            288 8                    12X4 3
- nwlui (2)                                             2307          1468            868            568                0         1176         1464
0                 0               432             1672            2888                     12843
Us/llll t2)Q Peak - Vs/hn (2 1
OHG          061            0 32           0 22           0           0 45           0 55 |
_________
0                 0                   O 16       065
1
1 08 1 1
i’i For K<j*■ rdmhbHiy kuwd ixi luiiu-lenn records nl Uambcli Aiinuiil nmaru uiUl mikmiiI
3) Auiiibitt 2 It riOLl lit BUgir c*iw ph«s J 2 J 47 h« in thvcrikEkd Mullum 1} CalxulftbcMl lor di vcrufieJ cropping (lslictti u. gAfM in Tallies -1 14liter* per second per hectare
RANG IRRIGATION PROJECT
FlGURE 4.1
GROSS MONTHLY IRRIGATION WATER REQUIREMENTS
FOR SUGAR CANE (40V.) - DIVERSIFIED CROPPING (60%) MW
(in l/s/ha)
12
MONTHS^ASWLnvsmwcs
VOLUME V
j Reservoir Operation Studies
T rcServoir operations were simulated with the HEC-5 computer model The simulation of a monthly routing of a 64-year time series Releases are made to meet monthly 
yrieatiori demand, shown on Table 4 16, as well as the minimum environmental release of 31 m /s
Table 4.16 Monthly Irrigation Requirements (m /j per 10,000 hectares)
J
J
j aJiutjuij1    —,——--- ■ TCfEfhLnHI&IVJ _------------ -----
8 60                                      July
5.50
6.10                                      August
0 00
X<Trrh
■ViaJtll
3.20
,,       -------— ------------
September
0 00
A nFIl
111
* ^P
2.20
- — ——
October
1 60
SVfsv
0 00
November
6 50
June
4.50
December
10 80
The   reliability   criterion   used   io   assess   the   irrigation   potential   of   the   reservoir   was   selected   as follows for each month at least 80% of the monthly water requirements are met 95% of the time
Based on the initial active storage in the reservoir shown on the Area-Capacity  Curve (Figure 4_2) of 139 4 mem, the water releases  can be regulated to meet the irrigation demand of the 53,147 hectares considered for this project, as well as the minimum environmental release
However, it is  anticipated that sedimentation of the [tang reservoir will significantly  reduce the active storage .Although there is  no specific  and reliable data for the project, it is  estimated that sediment accumulation in the reservoir could average 13 6 mem per year. This  could possibly result m a significantly reduced active storage after ten to fifteen years
Further analysis  has  also shown that with the development of the hydroelectric  project regulating reserv  oirs  in the upper basin, the need for active storage at the Itang dam becomes  less  and less necessary  As  indicated in Appendix  U of the Master Plan, the two most promising hy  dropow er projects  in the upper basin are Geba-A and Bare with installed capacity  of 17] MW and 210 MW' respectively  Based on the evaluation performed for this  Master Plan, these two projects  have a v ery  good rate of return and are excellent candidates  to be integrated in the interconnected system within rhe next 10 to 20 years  On that basis, the reservoir operation studies  evaluated the regulation provided by  the two reservoirs, Geba-A and Baro. This  analysis  shows  that this regulation would be sufficient to irrigate up to 100,000 hectares  at the Itang sire without active storage at the Itang dam Therefore if after several years  of development of the hang Irrigation Project it appears  that the reservoir is  losing pan of its  active storage, it is  likely  Lhat upstream storage will have been developed and it would be sufficient to compensate the sedimentation of Itang reservoir
“4 irrigation infrastructure
General
The irrigation infrastructure comprising the Itang Dam and the irrigation and drainage systems 3s laid out and a preliminary design was prepared for command of the 5j,147 ha net project
T *MS-ULG SnrXkoiw Rj^r
Plan
Chapter 4
61Elevation in meters
Area in km2
(TANG RESERVOIR Area-Capacity CUFV*
Figure 4.2^Asn.ri.m'sTwtzs
VOLUME V
rea  in addition, a
enable development
flood  protection  dike  system  and  drainage  pumping  scheme of low lying flood prone areas
are provided to
Dam and Resenw
S   Dam   and   Reservoir   would   be   the   storage   and   over   regulating   structure   for   the   hang location   Project   The   selected   site,   25   km   downstream   of   Gambela   and   10   km   upstream   of Tiana  strikes  a  reasonable  balance  between  length  of  dam,  storage  and  relocations  The  dam  crest
levation   is   limiied   by   flooding   conditions   at   Gambela   and   the   resulting   live   storage,   while ^dequate  for  initial  operation,  to  be  maintained  will  require  preventive  measures,  such  as  upstream borage,   or   a   combination   of   dredging   and   flushing   of   sediments   that   do   deposit   within   the reservoir   To   facilitate   flushing,   the   dam   will   be   provided   with   a   gated   spillway   with   a   sill elevation  close  to  river  bed  level  The  dam  is  sized  such  that,  before  loss  of  live  storage,  it  can provide  a  dependable  irrigation  water  supply  for  the  53,000-hectare  project  and  in  addition,  make minimum environmental releases of 31 mJ/s to the river downstream
Irrigation, Drainage and Flood Protection Systems
The  irrigation  drainage  and  flood  protection  systems  were  laid  out  on  the  available  topographic maps The layout is given in Drawing IT-2
A  main  canal  would  start  at  the  58  5  m7s  intake  located  on  the  right  bank  of  the  Itang  Dam  and would  stretch  along  about  53  km,  ensuring  command  of  the  project  area  Its  design  capacity  of 10  5  m7s  to  58  5  m7$  is  based  on  the  estimated  maximum  monthly  irrigation  water  demand  of 1.1  litres  per  second  per  hectare  for  continuous  24-hour  operation  (see  length  profile  on  Drawing IT-6)
A  cost  comparison  was  made  between  a  concrete-lined  and  an  unlined  earth  canal  solutions  In view  of  the  substantially  higher  cost  of  the  lined  canal,  at  this  stage,  an  unlined  earth  canal  was adopted.   However,   because   of   topographic   limitations   and   to   assure   command   of   the   irrigable areas,  the  gradients  will  range  from  0.00004  to  0.00005  and  the  resulting  velocities  will  range from  about  0  5  m/s  to  about  0  6  m/s  along  the  approximately  53  km  long  canal  A  roughness coefficient   of   0.022   was   used   for   the   main   canal   The   main   canal   will   supply   12   secondary (distributary)  canals  The  main  canal  will  be  provided  with  a  service  road  and  with  a  number  of canal  structures  (offtakes,  control  checks,  bridges,  drainage  structures,  etc)  Main  canal  freeboard would vary from 0.6 m to 0.75 m
Twelve secondary  canals  and a number of tertiary  canals  were also laid out The secondary  canals were designed for a unit peak  rate of 1.2 litres  per second per hectare The increased rate was adopted to add flexibility  in their operation The gradients  of the secondary  canals  range from 0 0003 to 0 00] and the velocities  range from 0.4 m/s  to 1.0m:7s, The maximum design Rapacities  of the secondary  system range from 1.6 m’/s  to 15.94 mJ/s. Their combined length is 
7.3   km   A   roughness   coefficient   of   0.025   was   used   for   the   secondary   canals.   Minimum freeboard  used  was  0  3m  The  secondary  canals  would  be  provided  with  a  service  road  and a Ppurtenant structures
Similarly_
a Slir ace drainagfi
f
beffl provi(Jei The system is formed by one main drain,
CVen Second  y/co I
ar
lector drains and a number of minor drains The drains are designed for a
8a «>-Akobo River Basin Integrated D«ek»pm“>« Muter Tian
62
Chapter 4PRE FEASI
BILITY STUDIES
VOLUME
v
capacity   of
1.5  litres   per   second
per  hectare,  which  is  based  on  the  concept  of  dewatering  a
->f
year return maximum 24*hour storm of 115 mm over a 9-day period.
The main drain was designed for a 0 0003 gradient, velocities ranging from 0 77 m/s to 0 95
and 0 5m freeboard The roughness coefficient used was 0.030. The main drain would be 13
km long.
The secondary  drains  were designed for a 0.0005 gradient, velocities  ranging from 0 4 m/s  to 0 95 m/s  and a 0.5 m freeboard Roughness  coefficients  used were 0 030 for the longer drains exceeding 5 m7$ capacity  and 0 040 for the small drains  with lower capacities  The total length of secondary drains would be 79 7 km
Typical canal sections are given on Drawings IT-8 and IT-9
Additionally,  a  typical  irrigation  sector,  having  a  gross  area  of  about  1,800  ha,  was  studied  based on the existing 1/10,000 scale map
Two layouts  were prepared for ihis  typical sector, one for surface irrigation (Drawing IT-12) and one for sprinkler irrigation (Drawing IT-13) Although both systems  are feasible, the sizing and cost estimate for pre feasibility  analysis  wfas  done for the surface irrigation scheme only  The purpose of this  study  was  to establish unit costs  per hectare of the tertiary  and quaternary distribution and drainage systems  The net area was  estimated at 1,631 hectares  or 90 percent of the gross  area The tertiary  and quaternary  canal distribution system was  sized for a peak  flow’ rate of 1.5 litres  per second per hectare The drains  were also sized for 15 litres  per second per hectare. Roughness  coefficients  used were 0 025 for canals  and 0.033 for drains  Gradients ranged from 0.0001 to 0.002. and velocities  ranged from 0.3 m/s  to 0.6 m/s. Freeboards  used varied from 0.20 m to 0 30 m The system would be provided with service roads  and appurtenant structures
Similarly, a layout was  prepared for the on-farm irrigation and drainage for a gravity  system The systems  were sized and a cost estimate was  prepared for the purpose of deriving a unit cost per hectare for the on-farm systems The layout is shown on Drawing IT-14
A  dike  system  was  laid  out  along  the  right  bank  of  the  river  in  order  to  protect  the  flood  prone areas  against  river  flooding  and/or  a  combination  of  high  river  stages  and  a  24-hour  storm  with a  20-year  return  frequency  The  layout  resulted  in  3  separate  dikes  for  the  uppermost,  middle  and lower portions of the project area
The dike system would consist of low earth embankments  with downstream rock  protection and a service road In order to dewater the protected area from heavy  storms  and from irrigation return flows, 9 low-head pumping stations  and a flap valve would be provided The pumping stations  would be equipped with electricity-driven vertical centrifugal pumps  and associated electrical and mechanical equipment The pumps  would discharge to the river at variable river stages by means of pipes built through the embankments and flap valves
.An  electric  power  transmission  system  would  also  be  pan  of  this  project.  The  system.  consisting of 33 kV and 13 kV lines, would supply the dam operating gates and the pumping stations
TAMS-ULG Itaro-Ak&bo River Basin Integrated Development Mailer PL
Chapter -IpgEFEASlBlLlTY STUDIES
VOLUME V
4 j 5 Estimates of Costs and Benefits
Construction costs were estimated generally as discussed in Annex 1G Wat<r
r
/->
Estimates, given in the Master Plan
,G   Wa,CT
-
Resources Cost
The main unit costs used, expressed in USS (Jan 1996), are given in Table 4 17
In    addition,    a    15%    allowance    was    est.mated    for    contractor's    mobilisation    and    temporary 
construction facilities 
>
Total  construction  costs  were  amved  at  by  multiplying  the  quantities  by  the  unit  rates  and  then
adding  a  20%  allowance  for  phys.cal  contmgenc.es  and  finally  a  10%  allowance  for  engineering
and administration
»
The  annual  operation  and  maintenance  costs  were  amved  at  on  a  percent  of  construction  costs basis, as follows
Description
%
Civil Works
05
Mechanical & Electrical
3.0
—       --------------- TT----  ------------ Transmission Lines
Irrigation & Drainage
1.0
Power costs were based on a unit rate of 0.06 USS per kWh (Jan 1996)
Benefits
Benefits  were estimated on the basis  of the projected production costs  per hectare and the estimated value of the produce based on commodity  prices, as  determined in Annex  3E, Economic and Financial Analysis, of the Master Plan More detail is  given in the Economic  .Analysis presented in Section 4 4 4
TaMS-U! G Bam-Akobo River Bavin Integrated Development Mailer PUn
Chapter 4
64pre feasibility studies
v »LUMt v
Tible4.17 Unit Costs (January 1996)
Item
Unit
1?   /rrigatio/i Systems
Hate
1 Cleaning. Irrigation
Hectare
6000“'
Stripping
T” m
1 50
Excavation, common, irrigation
m
3 50”“
Compacted fill, main/second incl hauling
nf
mr
.
5 60 '
Compacted fill, other
4 00
Concrete lining & formwork
nf
120.00
Wire mesh, w elded
i
m
3 80
Roadway gravel
mJ
. 25.00
i
Roadway base course
nf
1800
Structures
%
10%
bl 1            Dam
ZT Road improvement
-
1
km
39,546 85
r Unprocessed fill placement
Processed fill placement
Excavation, common
Rock excavation
Borrow excavation, common
Borrow excavation, rock
nf
m‘
m
mJ
r
..
Hauling fill material (over 2 kmi
Impervious core material
Fillers, drains, transitions
nr/km
m
i ■■
I JP
Riprap, placement
nf
3 62
9 04
3 39
4 80
2.26
6.78
0.51
11 30
16.95
129.94
56 50
79.09 |
5.65 |
Mass concrete
m'
90.39
Formwork
nf
Steel reinforcement
Structural concrete
Drilling for drains
Drilling for grouting and drains 
Anchors, incl. drilling and grouting
T
50.85 J
1,242 90
m
m
T
14,914 81
Grouting
T                             564 96
1 Unmeasuied items
% 1                   5%
4.4. The Recommended Project
4 4.1 Project Description
/tang Dam
ltang Dam will be of earilifill construction, $500 metres  long with a maximum height of about 14 metres  and its  crest al elevation 436.0. Although there is  reportedly  outcropping rock  at the spillway  site, most of the length of the dam is  expected to be founded on deep alluvium, and an upstream impervious blanket will be provided for seepage control
T aMS-VLG Bnro-A kobo River Bajm Integrated Dev elopment Mailer Plan
Chapter 4
65rBEFKAsn»n-nv studies
VOLUME V
assaee  of  floods,  a  gated  spillway  is  provided  with  five  8xl0-metre  gates  The  spillway  sill F °r    elevation  422.  approximately  nver  bed  level,  and  7  metres  bdow  low  pool,  to  aid  in  flushing ,s    f  ent    The  spillway  has  the  capacity  to  pass  the  (routed)  possible  maximum  flood  (PMF)  with , l^res surcharge above normal maximum pool elevation of 431 6
The irrigation intake is on the right bank and will be provided with ten 3x1 5-metres sluice gates 
r C al delivery' water level is at 428 5 based on minimum water level elevation 429 0 at the
reservoir and 0 5 in entrance losses
ryunne construction, the nver will be diverted into a 100-m wide diversion channel that will cut
off a bend in the river The channel is designed for the I 100 year flood The earthfill dam will
be built up to both sides of the channel and the concrete spillw ay constructed at the same time
The nver will then be diverted over the spillway and the remaining portion of the dam fill will be
D laCCd in the diversion channel The spillway sill is so low that if any problems should develop
during reservoir filling, the spillway can easily serve as a low-level outlet
The preliminary  design of the dam is  presented on Drawings  IT-3, IT-4 and IT-5 Drawing IT-3 presents  the plan of the dam. Drawing IT-4 shows  the dam cross-section and Drawing IT-5 presents the length profile of the dam and the spillway cross section
Irrigation
.An   overall   layout   of   the   irrigation   and   drainage   systems   and   the   flood   protection   dikes   and pumping  stations  is  shown  on  Drawing  IT-2  This  drawing  also  presents  the  axis  of  the  dam  and the irrigation intake location
The main canal will be approximately  53 km long The canal capacities  will range from 58 5 m7s at the origin at the intake on the right bank at the Itang Dam and 10 5 m7s at its lower reach The length profile of the main canal is  presented on Drawing IT-6 The typical cross  sections  arc shown in Drawings IT-8 and IT-9
The project will have 12 secondary  canals  with a combined length of 87.3 km Their maximum capacities  at the origin will range from 1 8 mJ/s  to 15 94 m3/s  The typical canal sections  are the vame as the main canal sections
The principal drainage system will include a 13 km long main drain with a capacity  ranging from 20 m /s  at its  upper reach and 50 m /s  in its  lower extremity; 11 secondary  (collector) drains  with
J
a combined length of about 80 km
In addition, gravity  distributions  and drainage systems  and on-farm systems  will cover the entire "rigable area covering 53.147 net hectares  A typical layout of the proposed gravity  system is Presented on Drawing IT-12 The on-farm layout is given on Drawing IT-14
A flood protection system is proposed for the low lying flood prone areas The system would consist of three earth dikes A length profile of the dike system is shown on Drawing IT-7. A
.pical cross section is presented on Drawing IT-10.
T AMS-l'LG Baro-Afcobo River Basin lnteRraled Development Master Plan
66
Chapter 4PREFEASlBiLjn STUDIES
V °LU,\je
Nine drainage pumping stations with capacity ranging from 20 kW to 260 kW arc prop    .
Os
(be purpose of dr*storing (he area behind the flood protection dikes The length p  .
ror
fOf
Drawing IT-10 indicates their location along the dikes A typical section is presented on D '
IT-11
raw,n8
442 (<«r Euimates
A   construction   cost   estimate   was   prepared   for   lhe   proposed   project   scheme,   as   desenbed section 4 t s above
'n
The estimate is presented in Tabic 4 IS A separate detailed cost estimate was prepared for th hang Dam (Appendix 4-1) and was subsequently incorporated in the project cost estimate The dam cost estimate is given in the appendix and referred to in Table 4 18
A summary of costs in January 1996 US dollars is given in the following tabulation
Preliminary
Itang Dam
Access Road to Dam
Main Canal
Secondary Canals
Main and Collector Drains
Flood Protection Dikes
Pumping Stations and Flap Valve Transmission Lines
Tertiary, Quaternary and On-farm System Levelling
Clearing
Subtotal
Contingencies 20% Engineering and Adm 10% TOTAL
45,431,000
50,064,000
40,000
24.143.000
20,128,000
4,335,000
14,865,000
975,000
2,850,000
107,091,000
26.573,000
6,378,000
302,873,000
60.575,000
36,345,000
399,793,000
In addition, an estimate of annual costs  was  prepared for the project. This  includes  construction costs, in accordance with a proposed project schedule given in section 4 4.3, and operation and maintenance costs  after construction The annual costs  for the period from 2001 to 2020 and
thereafter,  in  USS  (January  1996)  are  given  in  Table  4  19
4 4. J Implementation Schedule
A   proposed   implementation   schedule   was   prepared.   This   indicates   both   pre-construction   and con si ruction activities
Pre-construction activities include studies required prior to construction up to the feasibility stage, project finance activities, negotiation of concession agreements with commercial agribusiness ventures, and preparation of designs, specifications and bid documents for construction Construction is divided in 3 phases
TA MS-ULG Burn-Akrtbo River Biiin Integrated Development Mailer Plan
Chnpi*r4^feasibility studies
VOLUME V
'item
1 ____
j 18 hang Irrigation
Description____________
CosUt EnitstimQatuaent  - Uity
prelin 
i
i
Urtg Dam. includes embankment dam. ^illway.
1 ’    ------- —-------- r------—----------
LS
IS           1
2            iverwxi works, imgatu fl intake lj ________________
L ak Price
45.431  014 
50.064.25 f
_— — 3 
__ 4
Access Ro"d 10 DMn
------------------------------
J 1
4 2          Fill, compacted 4 3          Stopping
Mam Canal Excavation common
4 4
4 5
Gravel road wav 0 2m thick Base course 0 3m thick
46              Clearing
<7 Structures and mi sc
LS          1                     39
i
nr        4.900.0TX)     25
m' 1.100.000 56
m3 145.000 1 5
m3         39.000            25 0
m3          100,000           180
ha         400                  6000
LS      1
Cost
y 1 SOjMtJSI
'9 547 (24.142JOO)
12250.00) 6.160.000
5 5 1
Sccondarv Canals Excavation, common
2I75W 975.000
L8CO.OCC 240.000
.000                 2.500,000 (20.127.9I0r
5.2         Fill, compacted
5.3         Stripping
54          Gravel roadway 0 2m thick
55          Base course 0 3m thick
56          Clearing
57          Structures and mi sc 10%
6            Main and Collector Drains
6 1         Excavation, common
62          Clearing
63           Structures and mi sc
7            Flood Protection Dikes (2)
71          Dike No 1
72          Dike No 2
73          Dike No 3
8            Pumping Stations and Flap Valve 8 1         P S . No 1
82          PS No 2
83          PS No 3
84          P S No . 4
85          P S No 5
86          PS No 6
87          P S No 7
88          PS No 8
m1 1.147.000 2 50
»; I.85I.OOO 560
m1 300,000 1 50
tn3 61.000 250
tn 157.000 180
ha 440 6000
2,867J00 10365.600
450.000 IJ25.OX)
2.826.000 264.000
LS       1
1 829,810                1        -I1'
m
3
1.550.000       25
ha          100                 600
L.S 1
LS 11
LS 1 1
LS 1
400.000
6.290.000
6.480.000
2.095.000
kW        20                    800
kW       60
SCO
89 8 10 o
y,
PS No 9 Hap Valve
kW        260                  800
kW        100                 800
kW        210                  800
kW        150                 800
kW 100 SOO
kW 70 800
kW 230 860
LS    I 1
o 1 Transmission lines (assumes power it Gambell)
9 *>          Gambcla - Itang (33 kV)
Q “I
* 3
Iun 8 Dam and Dikes Nos 1 & 2 (33 kV)
in           PtkeNc> 3<13kV)
km 53
km 60
km 10
15.000
22.500
22.500
29.500
(4J35.OOO)
3.875.000
60.000
400.000
(14.865.000)
6.290.000
6.480.000
2.095.000
1975,000) 16.000
48.0CO 208.000
80.000
168.000
120.000
80.000
56,000
184.000
15,000
(2.850.500) 1.245.500 1.410.000
195.000
101
102
11
12
^ginon and Drainage Systems
(107.091205)
•farm Icniin A Quaternary Systems
ha
53.U7 
755 
40.125.985
On-farm Systems
ha
53.147 1260 
66.965220
_l evelling (3j_
ha 53.147 
500 
2t> <;>.j
Cxanng > low densin • 20% area
ha 10.630 
600 
6378,000
Subtotal
|
302,873,427
Contingencies ■ 20%
Subtotal
60.574.685
363.448.H2
Jj^pnecnng And Administration 10%
<0
□)
399.792^24
ULG Bam-a kobo River Baiin Integrated De'e lop men t Master Plan
68
Chapter 4Table 4.19 
Irrigation Project Annual Cosii - l<MO I’M (Jan. 1996)
1 Ywr               on
Copied Coiti
MAE           Trim-              Irrigation miidon           A
Unci               Drainage
r—]
Told                Ch II
MAE
OAM o»u
Tmni'
Irrigation          Primer
Tnc.l
Tnlal
rnhilon             A
Uno
Drainage
2001                25.976                     0                     0
0                25.976                   0               0
n                              0                     0                        O                 25.776 W
2002                37.525                     0                     0              5.080                42,605                   0
0o
2003               41.455              1,742                     0              17,732               60,929               129 88                     0                    0
2004                17,12.1            1,165             4 J 24              17,7.12             4O.343               317 20                     0                    0
2005                6.2411                    o                     0             14.997               21.245               524 48                   52 26               b
2006 12.593 0 0 HJR4 20,777 611.10 87.15 41 24
2007 12395 200 0 10,919 23.514 642 34 87 15 41.24
0 0 0 42,605 00
0 0 129 88 61,058 MX
76 20               0
391 40            40,7 U, 40
342 IM            50 IM)              968 92             22JII 72
(OH 16             50 00           1.377 65             22,174 65
813 12 5000 1.651 85 25.167 MS
2W8                        0                     0                     0              17,732
17.732
705 30                   87.15             4114
955 88              50 00            l 839 57
2009 0 0 0 17,732 17,732 767 28 93 IS 41.24
20)0 0 0 0 14.997 14,997 767 28 93 IS 41 24
r
2011
2012
2013
20H_
20] S
2016
2017 
' 20IR
2019
1 2020 &
1 lhenrnficr
5,f>27
1.11966 50 00 2,071 n
1.385 64 $0 00 2.337 3)
5.529             _IOO                     0              10,947               16,576
0—              <L .      8.184
13.811                767 28                   9115             41 24                   1.651 62              50 00           2,603 29
5.000
JOO
767 28                   93 15             41 24                   1,876 58              $018}          2,828 25
0              17.831
4,662                 247                 303
22531                79541                    93 15             41.24                   1.999 34
50.00           2 979 14
0
17.832               23044
00
19.571 57
19.801 33
17.314 31
16.411 29
19.404 25
25.910 14
26 217 99
_____ 0                     0
15,098
8.285
8.285
15.098
0
823 06 96 15 4121 2.163 54 50 00
848 06 99.15 41.24 2.411 01 50 00
0
__  0
0
00
00
8.285 871 37
5,911  871 37
5.911                         0               87137
106 56             44 27
106 56 4417_
106.56             44.27
106 56             4427
2,698 49 $0 00
2,92496 50 00
3 J 73 99
3,469 46
3,770 69
3,997 16
00
000
0
— - -
00
0               87137
871.37
106.56
44 27
—
3,049.23
3.173 51
3.262 17
5000
SO 00
SO 00
4.121 43
4,215 71
4.334 37
18,567 46
12,055 69 
I2JM2 16
10,032 4 3
4.245 71
4.334 37VOLUME V
I includes the hang Dam. thcjjpper portion (18 5 km) of (he main canal and all other features for development of 17,000 ha. including a first 7.000 ha module for commercial
prOje\ ne operations and 10.000 for diversified agriculture by small holders
•
1
~■
a
[|  includes  the  middle  portion  of  the  main  canal  (24  km)  and  all  other  requrred  features  for ?   additional   17,000   ha   development,   including   a   second   7.000   ha   module   of   commercial   sugar 3/1 ’ ^rations and a second 10,000 ha of diversified agriculture development by small holders
II Phase in includes the lower portion of the main canal (13 km) and all other required
"eatures for an additional 19.147 ha, including the third 7.000 ha module of commercial sugar
e operations and an additional 12.147 ha of diversified agriculture operations
The   construction   and   development   period   for   each   of   the   3   phases,   including   major   works, distnbution and drainage and on-farm development, would be as follows
Phase 1
Phase IT
Phase III
2001 -2007
2005 - 2012
2011 - 2013
Project    finance    private    concessions    and    design/specs/bid    activities    would    precede    the    above construction and development
Imgation construction and development would proceed at a rate of about 2.000 ha per year for each commercial and non-commercial operation with a lag between construction and on-farm development Maximum production would have an additional lag. as  described in section 4 4 4. Economic Analysis
The proposed implementation schedule for 1906 to 2018 is presented on Figure 4 3
4-4-4 Economic .4naiysis
The   proposed   irrigation   project   consists   of   two   separate   areas   of   cropping   with   one   area   under commercial sugar and the other under smallholder mixed agriculture
The  sugar  will  consist  of  a  total  of  21.000  ha,  broken  down  into  three  7.000  ha  blocks  Cropping intensity will be ] 00%.
The mixed fanning will consist of the following crops cotton, maize, sorghum, soya bean,
vc getables, fodder and oilseed, and will be cropped at an intensity of 100% in the wet season, and
in the dry season, for a total of 166%
TT*® net return (value of output minus  the cost of on-farm inputs) to the fanner for each of the Cr ops  is  shown in Table 4-20 This  table is  based upon the crop budgets  laid out in Appendix  5 to 3E, and the detailed computation shown in Appendix 4-2 of this report
T AMS-ULG B.tD-Akobo River Baiin Integrated Development Master Plin
70
Chapter 4FIGURE 4.3FEASIBILITY’ STUDIES
VOLUME V
Table 4.20 Economic Return of Crop fBirr/haj
Year I
Year 2
Year3
Yta r 4
Colton_____
Maize______
Sorghum___
(1291
2350
Q7
2353
4 514
6 770
U28
865
2d5J 
2,066
4.563
3,896
5.352
4,307
"Soya Beans
I
Vegetables^
Fodder
1,877
2,681
2,684
I
1
1878
10,148
3.873
2.606
10148
Oil Seeds
4.811
4.811
SugarCane (3.268)
15.321
22,024
22.024
The  build-up  of  cropping  for  the  proposed  imgation  project  is  summarised  on  Table  4-21  The build-up  is  shown  as  the  number  of  hectares  brought  under  each  of  the  crops  each  year  .As  can be  seen  from  the  tables,  the  first  acreage  is  brought  under  cropping  in  the  year  2004  and  then builds  up  gradually  For  sugar  it  is  2016  before  all  of  the  acreage  is  cropped,  for  mixed  cropping the full acreage is not cropped until the year 2018
Table 4.21 Cropping Build-up (hectares)
Year               Cotton           Maize
Sorghum
Soya
Vegetables
Fodder       OU Seed        Sox«r
2004                   800
1,100
580
400
40
100               300                2J00
2005                1.600
2.200             1,160           800                80
200
600               4.700
2006               2.400                3,300             1.740        J .200              120                 300
900               7.000
2007               3,200                4,400
2,320         1.600
160
400             1200               7.000
2008
4,000
5.500
2,900
2.000
200
500
I JOO               7.000
2009
4.800
6.600
3,480        2.400
240
600
1.800
9JOO
2010
5,600
7.700
4.060        2,800              280                 700           2,100
11 JOO
2011
6.400                8,800             4,640         3.200
320
800            2.400
14,000
J012
7.200
9,900             5,220        3.600
360
900           2.700              14.000
2013
s.ooo
11,000             5,800        4,000
400               1.000           J, 000             14.000
2014
8.800
12.100             6.J80         4,400              440              1,100           3,300              16.300
2015
9,600              13,200             6.960
4,800              480
1200
3.600             18.700
2016
2017
10.400              14.300
7.540
5,200              520              1.300
3.900             21,000
11 JOO
15.400
8,120
5,600              560              1.400           4 JOO            21.000
2'J18
12.000
16.500
2019
8,700        6.000              600               1,500           4/500             21.000
12,859
9.323 |                           643
17,681                              6.499 7 —- —          J,
1,607           4,822             21.000
In    Table    4.22    the    summary    of    build-up    ofbat^.^^Xlds    that
|S
occurs    over    a
s hown  This  combines  tw  o
period    of
things   the   gradual   increase   in   acreage   and   t   e   i   ,   .   ]On    can   be   seen   from   the   t   e,   tor
several years for each area as it is brought un er mixed cropping the benefits are not maxirmsed un faster build-up of yields, maximum benefit* come
2022. while for sugar, with a muc
thc ycar 20IS
TamS-(JLC Baro-Akobo Rjver Bubi Inte-ntcd Development Mwter Plan
71
Chapter 4P REF€ASiB»-in snores
Table 4.22 Benefit Build-up (million Birr)
Year
Colton Mint
2004                2008
(OB
10.9
2012
32.5
2016
542
26                     23 2                   46 7
70.3
2020
76?'
915
0.7
91 4
19.1
29.1
38 5^
Sova
0.3
" 5.0
11.5
17.7
-------
—
236
Vegetables
0.1
Fodder                        03                       36                      76
0.5                                      L-M
16
117
—- - - - - - - - - - - - -
117
I
155
Oilseed
0.3
36
7.6
155
Sugar
(7 5)
154 2
292 9
388 2
462 5
Toll!
(3.4)
210.2
418.9
584.2
724.8
All of the above tables are looking at the return from the agricultural outputs, minus the on-farm cost of this production As there is little or no established cropping in the area proposed for imgation. this represents a net benefit resulting from the project.
What is not allowed for above is the cost of providing the irrigation These are project costs and are shown in .Appendix 4-2, first of all as financial costs in millions of Dollars and then as economic costs in millions of Brer A shadow exchange rate of Birr 7 47 to the Dollar is used in conversions, as explained on page 8 of Annex 3E.
When the costs of the project are brought together with the value of the agricultural benefits, the cost-benefit stream shown in .Appendix 4-2 gives us a set of net benefits which are the project benefits after all costs have been met This net benefit stream gives an Internal Economic Rate of Return to the Itang Irrigation Project of 13%
4.4.5 Environmental Assessment
The hang irrigation project includes
•   the Itang dam and reservoir.
•    a 55 km-long unlined main canal conveyance.
•   a gravity irrigation system capable of imgating 53,000 ha of land.
•   a surface drainage system over a gross area exceeding 60,000 ha,
•    a flood protection sysiem composed of earth dikes and drainage pumping stations and
•   a road system for servicing the hydraulic infrastructure
The hang dam will impound the Baro River about 30 km downstream of Gambela Its site lies in the flood plain of the Gambela Region The crest length of the dam is 5,000 m. its maximum height 14 m and its construction will be an earth embankment The reservoir will inundate 71 km’ to contain 290 million cubic metres (mcm) of water Its normal minimum operating level is at El 429 0 and its maximum level is at El 431 6 m The mean annual flow of the Baro River at this location is estimated to be 390 m /s. Discharge from the dam will be diverted to irrigate a net
TAMS-FLG Baro-Akobo Rl'rr Baiin Integrated Development Marter Pi?„ ‘----------------------------------------------------
n
Chapter 4
72HtfFMSiMirrv STUDIES
volume v
,, M   of  approximately  S3.000  hectare!  The  ran  canal  rf  be  deitgned  to  come)  a  peak discharge of 58 5 m /s
Positive impact*
The subsequent section discusses inc potential benefits of (he reservoir other than those associated with the irrigation project
Flood_c^B^- The flood surcharge volume ot the reservoir is 170 mcm in addition to its active storage of HO mcm No significant flood attenuation is anticipated from the reserv oir operation
l^servoir fisheries The study by Sdkhozpromexpon (1988) estimated that the Adobo reservoir in the lower basin could produce an annual catch of 100 tonnes for its 2,210 hectares reservoir A similar harvest, subject to confirmation by feasibility study, would give a total annual
production of about j20 tonnes
Fuehood Among the mitigations recommended by this assessment is the total clearance of biodegradable material from the reservoir area The woody' biomass of the dam and reserv oir site has not been survey ed other than in the context of the 1995 IFootri Biomass Survey by Thenauh Using his results, the reservoir lies in an area whose potential dry woody biomass lies between 10 and 30 t/ha For the area of the reservoir (71 km ), this translates into a potential fuelwood
2
supply of between 71,000 and 213,000 lonnes At 5 Bin-per 20 kg bundle of fuelwood, its gross resale value, exclusive of the cost of collection and preparation, is between 18 and 53 million Birr (USS 2 8 and 8 5 million).
Recession agriculture and grazing Itang reservoir, because of its extensive, gently sloping shores, offers potential opportunity for recession agriculture and grazing during the dry season
Such areas have been traditionally used for dryland grazing in much of Ethiopia, and provide a focus  for  livestock  movements  throughout  savannah  tn  .Africa  The  Master  Plan  map  of agricultural systems denotes the reservoir as lying on the border between shifting cultivation (sorghum dominant) and pastoral systems The section on subsistence agriculture in the project setting describes the role of recession agriculture, which provides between 2 and 3 crops annually These opportunities are not in competition with irrigated agriculture, but complement it in ways 
that could provide additional project revenues  while reducing noxious  shoreline vegetation It would have to be controlled, however Excess livestock would deplete the natural vegetation of the area, break down canals, destroy crops, and starve unless their numbers were kept within appropriate limits
The project setting described in this report gives a rough evaluation of the manure-P and manure- that could result from livestock grazing in the reservoir area. Exposed on the surface and
object to intense evaporation and insolation, horse pats, cow pats, even elephant pats dry out and rot. changing their noxious components to ones that are more or less benign The use of high concentrations of deworming medicines can produce pats that are toxic to maggots, extending the period of time required for decay to take place
TAMs-1’LG Bi ^
rt  Akobo Rjver ^j^^dD^lopment .Murer PUn
73
Chapter 4I’RE FEASIBILITY STUDIES
v °lume v
Xegative cnvirvnmcntai impacts and their mitigations
Laijc  dam projects  cause irreversible environmental changes  over a wide geographic  area and thus  have the potential for significant impacts  The area of influence of a dam project ex(Cllt(5 from the upper limits  of the catchment to far downstream While there are direct environmental impacts  associated with the construction of the dam, the greatest impacts  result from thc impoundment of waler and alteration of water flow downstream These effects  have direct impacts  on soils, vegetation, wildlife and wildlands, fisheries, climate, and human population m the area The dam's  indirect effects  include those associated with the building and maintenance of the dam. the operation of the reservoir and the development of agricultural, industrial Or municipal activities made possible by the dam
The    negative    environmental    impacts    that    result    from    dams    and    reservoirs    could    include    the following
Construction camp,
•     Roads,
•     Dam and appurtenant works,
•     Dislocation of people,
Loss of land
Loss of historic or other features.
Loss of wildlife habitat.
Proliferation of aquatic weeds.
Deterioration of w ater quality,
•      Reservoir sedimentation.
Riverine fisheries.
Water-related diseases.
Conflicting demands for water, and
Increased land pressure.
Consmicfifni camp Construction camps  usually  comprise quarters  for between 200 and 600 men, and contain showers, cooking facilities, toilets, generators, fuel dumps, cement machines, parking areas  —  everything needed by  a small town Their design is  usually  temporary', although their useful life often extends beyond the period required solely for construction of the dam
The amount of land clearing for the camp is  likely  to be insignificant To the maximum extent possible, trees  should be left standing to provide comfort for the workers  as  well as  supply  a seed source once the camp is  decommissioned If people are to be resettled to provide space for the camp, the resettlement policy currently followed by The World Bank should be followed
The amount of natural timber harvesied for camp construction could be moderately  significant it no precautions  are taken Ideally, such timber should come from the area of reservoir impoundment Outside that area, its  impacts  are identical to those of logging destruction of native vegetation and disturbance to soil and water To the maximum extent possible, the project should make use of such materials as plastic and metal sheeting, plywood and concrete.
TOIS-ULG Baro-Akobo Rrver Baiin Integrated Dn. ek*pmcnl Master Plan
74
Chapter 4VOLUME V
fn aintef’an‘-c
commencement or luu^--------
c 0[jd waste should be incinerated al a location removed from the camp and nearby  households The design of sewage facilities  should bear in mind whether or not the camp will continue to be
used   afier    its   decommissioning.   If   it   is   to   continue   in   use   then   primary   sewage   treatment   is required, otherwise, extensive septic systems might be permissible
Roath The construction of the Rang Dam requires  1 km of road improvement Roads  have been shown to be an important contributor to soil erosion, primarily  because they  concentrate and distribute runoff as channel flow rather than as uniform overland or subsurface flow
Access  roads  will be constructed to a high physical standard (compaction, gradient, surface hardness) in order to accommodate the weight of heavy  equipment. As  these roads  are likely  to be used for many  years  following dam construction, the major structures  should be designed to safely  pass  the 25-year flood and the minor structure to safely  pass  the 10-year flood Temporary roads  should be constructed to a permanent standard if their use will continue following completion of the dam or other structure
Because roads are an effective means of access to inaccessible areas, they open areas to increased exploitation: logging, farming, hunting High standard roadway's  should avoid intercepting primitive areas, national parks, controlled hunting areas  and locations  of exceptional historical or cultural significance unless the means to control trespassing to these areas are available
The mitigations  of the potentially  negative impacts  of roadways  rest with competent engiiieenng design Longitudinal drainage is  likely  to require a raised bed and ditches  Cross  drainage should follow existing channels  and be designed to accommodate debns  as  well as  water and sediment
Culvert  outflows  should  be  constructed  to  a  level  below  the  stream  bottom  so  as  not  to  interfere with  the  passage  of  aquatic  life  Culverts  on  steep  slopes  may  require  an  energy  dissipator  before toy   discharge   onto   unprotected   land   A   Soil   Erosion   Control   Plan   should   be   developed   during to  project  design  and  precede  the  onset  of  construction  Its  purpose  is  to  provide  guidelines  for COntr°lling soil erosion, sedimentation and pollution
Th=  Soil  Erosion  Control  Plan  describes  the  location  and  type  of  controls  to  be  implemented  It
clearly identifies sn«-iai
« elands and primal forests, that require protection
Chapter 4
B “n>Ak.>b  Riv^Biuin lntegruted Ifewlop^nt
0
75FREFEASlBItm STUDIES
V °UJMt \
l, ml the tone and ana of exposure The potential for erosion is greatly reduced if a
size of the disturbed area is small or its duration short In some instances st abiluatlOn '
take place as part of construction - it would be wrong to wait until the final gradc
established
frtatn sediment on the site This principle is achieved by using devices that filter sedimen: from runoff or that detain runoff so that heavy particles will settle It includes the use of
materials such as silt fences, straw bales, brush barriers, and sediment traps and basins
Atougi’ inly the sediment and runofffrom the site. For this discussion we are concerned only with Itang Dam. not with regional management of runoff and sediment Diversion berms and channels might be required to divert clean runoff around the site
Dam and appurtenant works The total quantity of all material needed for construction of the embankment is estimated to be 3,450,000 m' Most fill will come from the reservoir area where its potential impact is mitigated by inundation Approximately 210,000 m’ of riprap are also required, possibly to be quarried from the kopptes that scatter the plain The koppics are not so common that they lack uniqueness, however, particularly in terms of wildlife habitat They will need to be surveyed by a trained ecologist and a determination of habitat value made
Dislocation of people Selkhozpromexport (1990) estimates that 711 households will be
dislocated by the Itang reservoir The World Bank resettlement criteria for dislocated people
should be followed The farmer gross margins for the reservoir area is estimated to be 800 Bin,
or USS 128, per year If relocation costs are taken to be equivalent to 3 years’ revenue plus assets (estimated at USS 500), they become USS 884 per household or USS 628,000 for the 711 households
Loss of land The reservoir will impound 71 km: The worth of its standing timber as dry w oody biomass has been estimated in a previous paragraph The previous assessment shows that 711 households  risk  being relocated It is  estimated that lowland households  cultivate on average about 0 8 ha each and that they harvest about 2 crops per year Each household, on average, aggregates an estimated gross margin of about 500 Birr per crop per hectare, thus the total worth of the lost agriculture (less assets) is 570,000 Bin (US$ 91,000) per year
Loss o f historic, cultural or aesthetic features These components were not assessed at this level of study but remain for feasibility investigations
Loss of wildlife habitat Itang Dam, reservoir and canals occupy pan of the north west em edge
of Gambela National Park The park is severely degraded and its wildlife population reduced However, the wildlife and habitat are issue that require additional study during feasibility 
investigations
Much of Gambela National Park  is  already  occupied by  a state farm and Abobo Dam and reservoir, and is dissected by connecting roadways Poaching by refugees and the SPLA are reported in the area
TaMS-ULG Biro-Akobo River Batin Jnlefraled Development Mailer Plan
Chapter-!rBE
rtA n.lUTYSTUDlM
S
VOLUME V
^hele^s   Sclkhozprorrexport   (1   ^88)   described   the   apparent   permanency   of   migrators-   routes 
N °*     Trinity     of     P^Poscd       Cana‘S       kadin?
fr0m Abobo
.
Dam        ™«e     travcrK     the     canal     route     it
10    ^des  orabout  every  1  per  every  1  0  to  I  5  km,  and  are  somethmg  to  be  prw.«j.  if  furtkr ^Xnfirw.Hs «**«"•
,
' l3nS resmo,r “shalkl* ,’*nh art average depth of 4 ! meires )
~  ,  uroa(j  (71  km2    reservoir  area)  The  water  will  be  warm,  oxygenated  along  its  periphery.  and 111    bably   provide   ideal   habitat   for   aquatic   growth   Drawdown   during   the   dry   season   may   allow Pr0    for   weed   clearance,  particularly   if   the  landscape  is   used  for  controlled  grazing  and  agriculture tin ^jf   phytophagous   fish   inhabit   the   reservoir   At   this   level   of   study,   rt   is   not   possible   to d^ermine   if   the   growth   of   weeds   will   be   problematic   for   reservoir   operations 
r^^nnon of water quality Water quality  is  affected when large amounts  of tropical vegetation are flooded bv  new reservoirs  The two important parameters  to lhe process  are the amount of biomass  (estimated as  dry  woody  biomass  between 10 and 30 tonnes  per hectare for liana) and the residence time of the water in the reservoir From a totally  empirical assessment of the hang Reservoir, it would seem that rhe short residence time coupled to the small reservoir area would place the reservoir out of the severe risk  category  For the purpose of this prefeasibility  study, it is. however, recommended that the reservoir area be totally  cleared of all biodegradable biomass
Itang will be warm during the low flow season, contributing to low dissolved oxygen concentration and thermal stability  Wind turbulence will agnate the surface and possibly contribute to some mixing of surficial water layers, but this  could be minimal if aquatic  growths develop a wind break  along the surface
/Anaerobic  conditions  will prevail along the former thalweg and in the vicinity  of the maximum cross  section Oxygenated waters  may  only  be several metres  deep, thus  the effects  of anaerobic decay  may  not be apparent along Lhe reservoir fringe Because the irrigation intake is  along the dam side rather than the centre, the problems  of reservoir water quality  may  not be apparent to water users  during the early  irrigation season Later in the year, when chemical processes  become more active due to increasing water temperarure, problems of taste and odour may increase
Be^ryvtr sedimentation As  discussed above, in the hydrology  and reservoir operation sections, sedimentation of the reservoir is  anticipated to be rapid, however, no reliable measurements  can be used to support this  assessment A sediment measurement campaign should be undertaken, pnor to initiate the feasibility' study  At the present level of study, sediment accumulation in the reservoir is estimated to be 13 6 million cubic metres per year
The   reservoir   may   interrupt   fish   migrations,   but   this   has   not   been   directly assessed   during   the   course   of   this   or   previous   studies   A   fish   ladder   and   hatchery   should   be considered
chrajgj A( this level of p
re ea
f  sibility study an assessment of the hang reserv oir
e   ar
Q 1'" 8  d to water-related diseases is speculative, only some indications can be drawn from
utSl e the project area and. indeed, from outside Ethiopia
Y      '—-—
77
Chapter 4
. ■•.PREFE ASIBILITY STVDIIS
v °lumKv
Itw's shallow. extensive rcscnw will favour shoreline growths that provide the breeding habits 
for mosquitoes, mites, midges, and other insect earners of dtsease Fast canal velocities co^
provide favourable brccdtnR habitat for the fly earner of Onchocerca sis The potential for
from the project needs to be studied extensively at the feasibility level
The nsk  of maiana and other diseases  related to mosquitoes, gnats, midges, and other insec( earners that breed or depend upon water (yellow fever, dengue. Onchocerciasis..) will change from being seasonal to becoming perennial The increase will result from improved breeding habitat offered by the reservoir and its shoreline vegetation Some of the nsks associated with these diseases can be reduced by controlling wetland vegetation, possibly by recession grazing
Ami-malanal programs using pesticides such as DDT pose their own set of hazards and cosy, and are not recommended given that many  of these substances  are banned Similarly, chemoprophylaxis is at best suitable only for short-term, non-immune visitors to the project area
The development of immunity and treatment of lhe population living near the reservoir is, for now. an admittedly partial solution
The literature associates rivers with outbreaks of trypanosomiasis, but information about this disease is fragmentary and inconsistent Selkhozpromexport (1988) reported an unconfirmed 454 cases of trypanosomiasis in the upper Gilo River, but this is believed to be adjacent to the lowlands The Gambela hospital reported 1 case in 1981 and 7 cases in 1985. Feasibility studies will need to gather information on the frequency of this disease in the proximity of the site
Selkhozpromexport (1988) reported the absence of the mosquito earners of Leishmaniasis in the lower basin There is no information about their continued absence
The fly associated with Onchocerciasis prefers fast, shaded streams for its egg laying, and may make use of canals where these become overgrown with vegetation The removal of vegetation either side of canals is one obvious control, the use of pesticides another, thought these pose their own set of risks and costs
The snail carrier of Schistosomiasis  is  reportedly  absent from the Alwero River (Selkhozpromexport, 1988), it is  also absent from the Baro Different alternatives  are possible (o reduce the risk of Schistosomiasis
(1)  quarantine newcomers to the area,
(2)  improve health education in order to break the human link between man and water,
(3)  inject molluscides into irrigation water.
(4)  design canals to be fast flowing and root out any vegetation, or
(5)  line the canals
Detailed investigation should be undertaken prior to initiate the feasibility  study  In particular, problems amving. if any, at the existing irriganon project in the Gambela plain i e at the Akobo reservoir, should be studied and used in the elaboration of the environmental impact assessment
Conflicting demands  for waler. Provisional minimal continuous  releases  from the Hang are computed at 8 percent of mean annual discharge or 31 m’/s. Feasibility studies will be required to evaluate the effectiveness of this discharge to sustain present populations of water organisms and competing water users The present study has not been provided with sufficient data to
TAMS-ULG Biro-Akobo Rher Batin Integrated Development Mailer Plan
78
Chapter7PBl flASBILIn         STUDIES
_ R _____ f ___________________________ VOLUME V
flow
dnlled into non-leaky aquifers offer anoUer respsme ft is
study
increased     land     pressure shows there is no pressure
The   map   of   population   support   capacity   prepared   for   this   project on land in this area
Chapter 4
1  01 M“terPUfl
^S-ULXJ Berts-Akobo River Basin Inte^med Develop" *
79PREFEASIBILITY STUDIES
APPENDICES
TAMS-ULC Baro-Akobo River Batin Integrated Development Mailer AppendicesAPPENDIX 2-1
GEBA HYDROELECTRIC PROJECT Detailed Cost EstimatesTAJHS CofttuMjHtx he
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
M<i. R«. Lmh EL 2.170 Own Type
Inst Capacity: 112 MW *H MW
E jrttrfUl
_______________________________________________________________
Hem
Ng !    jr CIVIL VUOHKS
□AMS AND APPURTENANT WORKS
Co%l Lr-rr<.           Jan-M Amoont
Local
Foreign
Total
1o
2.0
3.0
4.0
5.0
POWER PLANT NO.1
Sion waterways no.i
POWER PLANT NO.2
DIVERSION WATERWAYS No 2
TOTAL CIVIL WORKS
b- electro-mechanical EQUIPMENT dams and APPURTENANT works
POWER PLANT No.1
DIVERSION WATERWAYS No.1
7.085.981
1.155.196
1.907,561
931,915
3038,845 14 119 293
;t
28.343.923 4,620.783 7.830.245 3,727.662
12,154.531 56,477.194
35,429,903 5.775.979 9,537.807 4,659.577
15.193.227 TO.596,492
1.0
2.0
3.0
4.0     POWER PLANT No 2
5.0
60
DIVERSION WATERWAYS No 2
transmission lines
TOTAL EQUIPMENT
202.800
5,649,424
21.600
3,799,745
21,600 6.300,000
16,675,169
1.131.200 46.215.796
06.400 32.092.782
86.400 25,200.000
104.812.578
1,414,000 51.865.220
108.000 35.892.527
108.000
31.500.000
120.817.747
L
TOTAL BASIC COST
Physical Contingencies 20% Engineering and Administration 10%
TOTAL CONSTRUCTION COST
30,194,468 6.033.894 3,623.336
39,856,698
161,239.771 32.257,954 19,354,773
212,902.498
191.484,239
38.296,548
22,973.109
252.759,195■AAOAXOeO PROJECT
MmI«<
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Max Rtv L*v»l: EL 2.170 Dam Type:                             Earthfifi Will Capacity: 112 MW £72 MW
item
No. 0€ SCRIPTION
Local
JC CIVIL WORKS
Amount
ForeiqrT'
1.0    c JAMS AND APPURTENANT WORKS 1.1   F *rHiminanes
12    1  access Roads
1.3      CAversion Tunnel
1.4    ( Cofferdam
1.5      fEmbankment Dam 1.6    IISpillway (separate from dam) 1.7    IILow-level Outlet
1,062,897 390,723
1.055.080
145,289
2,680,548
1,711,613
39.850
TOTAL 1.0
7,085,981
2.0      POWER PLANT No.1 21       Preliminaries
22       Access Roads
2.3
2.4
2-5
2.6
2.7
Power Intake Penstock (surface) Powerhouse (surface) Tailrace Channel
| Switchyard
173,279 85.421
126.252 216.479 487.239
0 66,525
4.251.588
■>.562.892
4.220.322
581.076
10.722.192
6 546.452
159.401
28.343.923
693.117
341.685
505,006
865.916
1.948.957
0 266.101
13.402
8.556 Cea
1992;
35.421
866397
427.1M
631251
1.082.395
2.436,188
0
332.627
TOTAL 2.0
1,155.196
4.620.783        5.775 17!
3.0 DIVERSION WATERWAYS No.1
3 1      Preliminaries
3.2      Access Roads
3.3      Diversion Intake
3.4      Diversion Canal
4.0     | POWER PLANT No.2
286.134
15,819
186.930
1,418.679
TrtTAi *i n
1 (J 1 AL J.U
4.1
A2
4.3
4.4
4.5
4.6
4.7
Preliminaries
Access Roads
Power Intake Penstock (surface) Powerhouse (surface) Tailrace Channel Switchyard
1.907,561
139.787 17.401
126.252 120,631 453.004
0 74.841
1.144.537
63.275
747.719
5.674.715
7,630 245 I
559.149
69.602
505.006
482,524
1,812.016
0
299.364
3.727.662T
1.823.187
158.187
747.719
9,425.488
12.154.58VL
1.430.87’1
79.094
934.6U •
7,093.394
F537JL
898.93’
87,1V-'
631.2«
603.1M |
2.265®^
0
374 205 ’
TOTAL 4.0
931.915
5.0 DIVERSION WATERWAYS No.2
5.1       Preliminaries
52        Access Roads
5.3
54
Diversion Intake
Diversion Canal
TOTAL 5.0
455.797 39,547
186.930 2.356.372
3.038 645
-----TfitTsnJ
197.7*
934,
11.76’ ^ I
J5J^TAMS CcriWftanU. Ax.
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE Max. ta. Lmt El. 2.178 Own Type, tartnftu
taLC^BdlF 111 MW * n MW
description___________ _
B: ELECTRO-MECHANICAL~EQu]pj^j^jr
dams AND APPURTENANT WORKS'’---------------- ----- Power supply to the dam
Intake and Bulkhead Gates - Low Level Outlet High Pressure Slide Gates - Low Level Outlet
TOTAL TO
Local
Co» Lrvrl:
Amount
Foreign
Total
POWER PLANT No.1
Power Intake Gales
Penstock
Inlet Valves
Turbines. Governors and Auxiliary Equipment Generators and Generator Auxiliary Equipment
Powerhouse Crane
Slation Auxiliary Mechanical Equipment Slation Auxiliary Electrical Equipment
Main Transformers
Switchyard Equipment Unmeasured Items
DIVERSION WATERWAYS NoJ
Diversion Intake Gales
POWER PLANT No.2 Power Intake Gates
Penstock
Inlet Valves
TOTAL 2.0
TOTAL 3.0
Turbines. Governors and Turbine Equipment Generators and Generator Auxiliary Equipment
Powerhouse Crane
Staiion Auxiliary Mechanical Equipment
Stalion Auxiliary Electrical Equipment
Main Transformers
Switchyard Equipment
Unmeasured Hems
—___ __ ____________________TOTAL 4.0
DIVERSION WATERWAYS No.2
Benton Intake Gates
TOTAL 5.0
P^nsmission lines
SC ^?ans- Line from P P »1 10 P P 91
KV Trans, Line from P.P. #1 to Gilflel Gibe
TOTAL 6.0
10.000
12.000
260,800
282.800
21.600
820.0X0
296.000
1,180.000
1.344,000
25.000
151.200
534.400
280.000
483.600
513.584
S,649,424~
21,600
21,60(T
21.600
361.114
204.000
963.000
915,000
25.000
108.000
322,000
186.000
348.600
345.431
3,799,745
21.600
21500
525,000
5.775,000
6,300.000
40,000
48.000
1.043.200
1.131.200
36.400
3230.160
2.664.000
10.620.000
12.096,000
225,000
1,360.800
4,809,600
2.520.000
4.352.400
4,201,438
46,215,796
86.400
86 400
86.400
1.444,456
1.836.000
8,667.000
8.235.000
225.000
972,000
2,898.000
1.874.000
3.137.400
2,917,526
32.092.782
86.400
86.400
2.100.000
23,100.000
25.200.000
50.000
60.000
1 304 000
1,414,000
108,000
4,100.200
2,960.000
11,800.000
13.440.000
250.000
1.512.000
5.344.000
2.800.000
4.836.000
4.715.020
51.865.220
108.000
108.000
108.000
1.805.570
2.040.000
9.830.000
9.150.000
250.000
1.080.000
3.220.000
1.860.000
3.466.000
3262.957
35.892,527
108,000
108,000
2.625.000
28,875.000
31.500,000BA RO-A KOBO PROJECT Integrated Matter Plan
TAMS Con»uM«nt», Inc- 00-Dec *3<
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
A: CIVIL WORKS
1.0 DAMS ANO APPURTENANT WORKS
1.1
f11
PreWmlnartea______________________ _ Mobdgalton
%
1 12       Land acjj'Mfiun 1 1 3      SO clearance
_________ ha
ha
Subtotal
15 00
2.259 02
1 694 87
15 00
000
6 779 46
1500
2,259 82
8 474 33
0
0
1 062 897 ___0
0
1.062.697
4,251 588 __________ 0^
______ 0
4.251.588
5 314 485
________ ________ 0
5.314.465
1.2
ttt
Access Roads
94 912
379 650
474,562
Road jmprovement
7,909 37
31 637 48
39 546 85
1 22
New Road________
17 40061
69 602 46
87 003 07
295 810
1,183  242
1 479,052
1 23
Stream Ci naming
________ 0
1.562.892
________ 0
_________ ] No
22590 20
90,392 80
112 991 00
12
17
0
_____0
390,723
1 953.614
Subtotal
.
1.3.1
1 3           01 veraion Tunnel
P<xtaJ excavation
cum
1 36
5 42
6 78
5 000
6.780
27.120
33.900
132
Tunnel ••cavalton
cu rn
10 17
40 68
50 85
21.237
215 980
863 921
1 079.901
133
Tunnet tupputi- rock bo«*
1 34
T
1 355 89
5 423 57
6 779 46
53
71 591
286.364
357 955
Tunnel support . shotcrete
1 35
1 38
*<q m
5 65
22 60
28 25
1 602
9OS1
36 205
Tunnel support . archei and nbs
Concrete mng
45 257
T
451 96
1 807 86            2.259 82
5
2 260
9 039
1 1 299
137
1 38
139
1 3 10
1 3 11
1 3.12
Structural  concrete
Formwork________
Sleet reinforcement_______ DrUUng lor grouting and drain*
Unmeasured ilema           '
“
Subtotal
cu m
eg m______ T_________ m
T_________ %
25 99
10 17
24858
IS 82
112 99
500
162.70 103 95
_______ 40 68 994 32
63 27
451 97
500
203 38 129 94
_______ 50 85 1.242 90
79 09
564 96
5 00
5 781 800
13 200 " 751
4 260 _______486
235 148
_______ 20,790
______ 134244
______ 186684
67.385 _______ 54925
50 242
940 592 _______ 83 162
536 976 ______ 746 734
269 539 F                  219 702 1
200 968 /
1,175 740
103 952
671 220
______ 933 418 336 923 /
274.627 /
251 210 /
1.055 080
4.220.332
5.275.402CUAKOBD WOJfC T
TKM& Coi«uM.Mnt%,ln>C.
Integrated Matter Plan
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Max. Ret. Level: EL 2.17a                    Dam Type: EirthM
Init. CapicHy: 111 MW t. 72 MW
CoMLevtE Jan 96
Unit Pike*
Amount
|
Item
No.
□ESCRIPTION
Unite
local
US 1
Foreign
US*
Total
1 us*
Quantities
Local
USI
Foreign
USS
Total
US* |
A: CIVIL WORKS
1.4 Cofferdam
141
Foundation tucavalcn - Cnmrrwi
cu m
072
2.90
3 62
16,075
12 218 1
48«ro
Gl OBB '
1 42
r our dalton excavallon ■ Rock
cu m
1 ai
7 23
0.04
0
□
o
0
143         '
Borrow eacavallon - Eirlh
to m
0 60
271
3.3©
102 400
S9.427
277.700
347.136
1 44
Borrow rxcevalion ■ Rock
cu.m
096
3 84
480
4.500
4,320
I7 2BO
21,600
145
naming fill mateilel (over 2 km/
cu.m/JoTi
0.10
0.41
DS1
0
0
0
0
t46
Unprocessed full (placement)
cu.m
0.45
1 81
226
102 400
46 285
155 139
231 424
1.4.7
Proceaaed fill (pteeem«M]
cu m
1 36
5 42
6 78
4 500
6 102
24.408
30 510
h 46
Unmeasured Name
%
500
5 00
500
6 918
27,670
3*1 508
Subtotal
145 269
581,075
726.345
1.6            Embankment Dam
151
Foundation excavation - Common
cum
072
2 90
3.S2
327 000
236.748
946 992
1 183.740
1 52
Foundation excavation - Rack
cum
1 61
7 23
9 04
16000
28 928
115712
144 640
153
fioriow erceveihon - Earth
cu m
0.68
2 71
339
150 600
102,107
408,427
510,534
p 54
Borrow eiccavaLion - Rock
cu.m
0,96
3M
4H0
0
0
0
0
1 55
Haubng fie material i roc-r 2 km)
cu rrukm
0 10
041
0 51
Q
□
0
0
1 SB
Impemoua core
cu m
2 25
9 04
11 30
637.500
1.440,750
5763,000
7 203,750
1 57       | Unpiocessed IM [placement I
cu m
Q 45
1 61
226
642,600
290 455
T, 161 621
1 462,276
i5e
Proc»>ed IW (placement]
cu m
1 36
542
6.7B
0
0
0
0
1 59
Fillers
cu m
3 39
13 56
1695
84 100
285 099
1.140 396
I.42S.49S
1 5 ID
Or erne traneUona
cu.m
3 39
13 56
16 U5
0
0
0
0
1.5.11
1 R*p-rep (pla-eenwnij
cu m
1 13
452
5 05
i a,soo
22,487
89 948
112,435
1 5 12
Drifting Io* 5'outing and di tin*
m
1130
45 20
56 50
5.200
58,760
235 040
293 800
1 513
Grouting
T
112.99
451 97
56*196
775
9T569
350,275
437 844
1.5,14
Unmeasured itema
U
500
500
5 00
127 645
MO.Ml
638 226
Subtotal
2,680,548           10.722,192          13,402,740BAROAXOBO PROJECT
TAMS ConiuH^'' HK=-
11-Doc -••
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Darn Typo:
Earthflll
Mas. Rea. Lavs*: El. 2.171
Cost
■Jan-1
Unit Ericas
For sign
Tots*
Local
Foreign
US S
Quantities
[DESCRIPTION
Ttio^orfwuMKOBO PffOMc r
(ntegjaled Master Plan
’TAMS
take.
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Mu. Res. Level: EL 2 170
(
D*m Type: EaflhlMI
Init. Capacity: 1 tl MW * 72 MW
CoM Level:           Jan-96
UnK Prices
Amount
|
Item
No.
description
Units
Local
os>
Foreign
US 1
Tom
US 1
QuaniMlea
Local
US i
Foreign
US t
Total
222 1
A: CIVIL WORKS
2 J      POWER PLANT No,i 2,1          Preliminaries
2 1 1 I Mcblkzition
US
15 00
15W
1500
173,270
693 117
966 397
212
Land acouiwtlon
ha
2 259.82
0.00
2.259,82
0
0
0
0
2.1.3
Site clearance
he
1.694 87
6.779 48
a 474 33
0
0
0
0
sublotll
173.279
693,117                 B8«,397
2 2 ACCttS Roads
22 1         F
toad Imp*avement
km
7,909 J7
31.637 46
39 546 05
2
15,819
83275
79,094
Z2.2
4** Road
km
17,400.81
69,602 45
67.003 07
4
69 602
278 410
340 OT2
223
Stream Crotslfig
No.
22,598 20
90.392 60
112,991 00
0
0
0
0
Subtotal
85.421
341 685
427.106
2.3           Power Inlsfce
f23L
Etrlh exeat; Blilon
cu m
0 72
2 90
362
300
217
B69
1.086
12 3 2
iFtock excewalton
cum
1.81
723
904
0
0
0
0
2 33
1 Lining, conciein
cu.m
40 06
162 70
203 38
0
0
0
0
Structural concrete
cu m
25 99
103 95
129 94
1,350
35 084
140 335
175 419
2.3.5
Formwork
m
10.17
40 65
50 05
4,050
41 189
184 754
205 943
2 3 6      | Steel relnfacanieni
T
24Q50
994 32
1,242.90
175
43,750
175.000
2T8 75O
23 7       1 Unmeieuroii lllamt
%
500
500
500
0,012
24 048
30,060
Sublolal
126.252               505.006            4 631,256
241
Common esciwallan
cum
0.72
290
302             4,200
3041
12,163 1
15204
242
Rock excivilloo
cu m
1 Bl
7 23
904
1.223
2 2M
0 845
11 056
2 43
Anchor belli
m
1356
54 23
87 79
0
0
0
0
2 4.4
Meet concrete
cu.m
18 08
72 31
00 39
2,446
44 219
176 875
221,094
245
SLruclUtil concrete
cum
2599
103 95
12994
0
0
0
0
246
ForrnwCHk
iqm
10.17
40.60
5085
8 987
91,398
365,591
456,989
247
Steel relrtorcement
T
248 58
994 32
1,242 90
225
55.931
223,722
779.653
2 48
UnmeevureO
%
10.00
1000
10 00
19«0
78 720
98,400
SuMclel
216 479               B6S.016           1.062,395BARO-AKOBO PROJECT
Inlegratad Mauer Plan
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Mai. Rai. Level: PL 1.178
Item
No._____ DESCRIPTION___________________________________ j Until |
UnM Price*
Local I ForeM"
US t 1 US 8 _
Dam Typo:
Inti. CapacMy.
Tofal
Earthfin
112 MW* 72 MW
USS             j Quantlllei j
Local
US > 1
Coat Laval:
Amount
Foreign
USS
A: CIVIL WORKS
1.1
2 5.1
252
Common excavalkxi_____________________________ Rock encavalion
FarfhfiN
eu m
cu m
cu m
0.72
1 81
045
2 90
7 23
1 61
3 62
904
2.26
11 340
14 200
4 030
8.210
25.674
1.622
32.841
102 694
7.286
25 4
Man concrefe
cu m
1008
72 31
90 39
2,258
40 620
163 280
Jan-AS
Total
US $ |
41 051 128.368
9 108 204 101
25 5
Structural concrete
cu m
25 09
103 95
129 94
2.872
74 638
298.550
373 188
256
Farmwork
•q.m
10 17
40 68
50 85
6 501
66.115
264 461
330.576
25 7
Sreet riinforcamenl
T
248 58
994 32
1 242 90
506
125 781
503 1 26
628 907
256
Roofing
sq m
180 79
723 14
903 93
323
58 394
233,576
291 969
259
Bloekwork
«q m
9 04
36 16
45 20
900
8 136
32 544
40 680
2 5 10
MiiceUaneou* Metahwxk
T
723 14
2 892 57
3 615 71
40
28 926
115 703
144 628
2511
Slope Protection
*q m
2517
452
18 Ofl
22 60
980
4.430
17 718
22.148
Jnmeitured items
|
1000
10 00 1               1000
44 294
177.178
221.472
Tatfraca    Channel
Common ejrcavalion
Rock  ixcavafion
Unmaaiured Ifam*
487 239
0
0
0
1.948,957
0
0
0
2.436.196
Switchyard                                                                                                                                                                                                                                                                0                              0 Common Helvetian
0
0
0
0
Rock excavator)
Fourxlahon* and duct*
Unmeasured iam*
497 18               621 45
13 032
_____ 0
29.830
17616
6.048
66. STS
52.128
______
119 318
70,464
24 191
268.101
332.6276ARO-AKO&O PROJECT
TANIS Contufl.BiMLk.lnc.
Inlfftted
Pl*n
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Maa. Rer Level: EL 3.17®                    Dam Type: EarthflH
IniL Capacity: 111 MW € 72 MW
HOK-U
Coil level; Jan-36
Unit Prices
Amount
|
Ham
No.
DESCRIPTION
Unite
Local
ust
Foreign
US 1
Total
US I
Quantities
Local
us$
Foreign
ust
Talat          1
US I J
A: CIVIL WORKS
3.0 DIVERSION WATERWAYS No.1
3.1 Preliminariea
3.1.1
Mobniaatlon
L.S
1500
1500
1500
286,134
1,144,537
1.430,671
312
Lind BLqujsrtion
hi
2.259.82
000
2,259 82
0
0
0
0
313
Site clearance
he
IBM 57
6.779.46
8.47433
0
0
0
0
Subtotal
266.134             1.144,537             1,430,671
32             AccatB Road*
32 1
Road Improvement
km
7 BOO 37
31 637 46
39,546 85
2
15,519
63 275
79094
3 24
New Road
km
17 400 01
69 502 46
67.003 07
0
0
0
0
325
Stream Crossing
No.
22 598 20
00 392 80
112991 00
0
0
0
0
Subtotal
15.819
53.275
79.094
3.3           Diversion Intake
h 3 1        1 Eerlh ewe aval ion
CLi Hl
0.72                    290
362
1 575
1.140
4 551
5 702
3.3.2       | Rtjck escalation
cum
1 51
723
9 04
1275
2.305
9 221
11 526
333
Maia concrete
cu m
1008
72 31
90 39
2550
46 099
154,396
230 495
334
Structural concrete
cum
25 09
103 95
129 94
1 350
3S 084
140 335
175419
335
iFormwoik
uq m
10.17
40 68
50 85
4682
49 650
198,600
248 250
33 6
Sleet remtorcemeni
T
245 58
904 32
1,242.90
170
43 750
175,000
218 750
337
Unmea»u*ed tem»
L*
500
SOO
S 30
0 901
35.606
44 507
Subtotal
106,930
747.719               934,648BARO-AKOeO PROJECT Integrated MaiUr Plan
TAMS Cofliu^nii. Inc.
0<-Dec4S
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
UnM Pf Icefl
Foreign
Cort Level: Anwunf Foreign
J>n-»C
Total
Nam
No.
OCSCR^TION
um<» J
Quanhlles
SubCol al
1 418679
,674.auuro  akobo
nROjEC
r
TAMS Cop*uttanU>\
n£.
/nlegrefed
A/*n
GEBA HYDROELECTRI
C PROJECT
QlOttM
PREFEASIBILITY
STUDY
COST ESTIM
ATE
Mat. Res. Level: El. 2,170
Oam Type; Earthfffl
Inti. Capacity;  112 MW A 72 MW
CoelLevek
Jan-84
1—  "1
Unit Prlcea
'
Amount
<
litm
1 DESCRIPTION
Unite
Local
USS
Foreign
USS
Total
USS
|       Local Quantities |          USS
Foreign
USS
Total |
US» |
A: CIVIL WORKS
4.0 POWER PLANT No.2 4,1 Prttimlnirlts
ifobllization
4 11
L.S
1500
1500
1500
139 707
559149
698 937
4.1 2
.■nd acqutS-lrtMi
ha
2.259 82
ooo
2259 82
0
0
0
0
413
:Site clearance
1        1 694 87
6.779 -16
8.474 33
0
0
0
Q
Subtotal
139.707
559.149
698.937
4.2           AccataRoade
4 2.1
Htkid Improvement
MfTl
7 909 37
31 637 46
39 546 65
0
0
0
0i
422
Hew Raw
km
17 400 61
60.602 46
87,003 07
1
17.401
89,602
67 003
4Z3
Strom Grousing
No.
22 596 20
90.392 80
112991 DO
0
0
0
0
Subtotal
17.401
69.502
87 003
4.1           Power Intake
4 3.1        Earth excavation
cu.m
072
2 90
362
300
217
869
1 DS6
432
Rock rxovallan
cu.m
1.81
7 23
904
o
0
0
□
14,3.3
Lining concrete
cu m
40 68
162 70
203 38
0
0
0
0
43.4
Structural concrete
cu m
25 99
103.95
129.94
1.350
35.084
140.335
T75 4I9
435
Forrmvork
sq m
10 17
40.60
5O.U5
4.050
41 189
164 754
20590
436
Steel relnrwcemeM
T
246.58
994 32
1,242 00
176
43.750
175 DOO
210 750
4 3.7
□nme*tu*ed /erne
%
5.0D
5 00
5.00
6.012
24.048
30 050
SubloLal
126.252               5Q5.CO6              63 T, 250
4.4           PenHock (surface)
4.4.1
Common eicavalmn
cu.m
072
290
3.62
2 400
1 738
6.950
6 688
442
Rock ewcaval Ian
cu m
1 81
723
9 04
two
1.157
4 620
5 788
4.4.3
Anchor twits
m
1356
54 23
87.79
0
0
0
0
444
Mast concrete
cu.m
1808
7231
90 39
1.2BO
23 J 40
92,559
1 15.699
4.4.5
Structural concrete
cu.m
25 99
103 95
129 84
0I
0
0
a
4 46
Formwork
sq.m
1017
40.68
50 85
5.119
52.060
206 741
260301
447
Steel reinforcement
T
248 56
994 32
1,242.90
127
31 570
120 279
157 848
4.4 B
Unmeasured Hems
%
10.00
1000
10.00
10 966
43 BM
54 832
SubMat
120.631
482.524
803,154jams
,nC‘
BARO-AKO8O PROJECT Integrated Master Ran
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Darn
Earth fl II
Me*. Rea.
Unit Price*
Foreign
US I
Quanlrtie*
10600
7619
Cost Level:
Foreign
US t _
31 277
Jan-M
Total
US >
DESCRIPTION_________
A: CIVIL WORKS
39 096
105 678
Subtotal
453.004
4.f 46 1
Ta Hr ace Channel
Common racavabon
cu m
0 72
290
3 62
0
0
0
0
46 2
cu m
1 61
7 23
904
0
0
0
0
46 3
Unmeatured aems
500
500
500
0
0
0
Subtotal                                                                                                                                                     0                            0                              0
4.7          Switchyard
47 1
Common axcawfon
cu.m
0.72
2 90
3.62
20.250
14,661
56 644
73 305
472
Rock etc aval ran
cum
1.81
723
904
0
0
0
o
473
Foundation and ducts
•q.m
124 29
497 16
621 45
270
33 558
134 233
167.792 1
474
Surfaorg
sq m
1.47
587
7 34
13 500
19.818
79 272
99090 1
4.7 5
Unmeasured liema
%
10 00
1000
1000
6 804
27,215
.14.019 /
Subtotal
74.641
299.3T14                    J74 205BARO-AKOBO PROJECT
tntegr^ird
PUn
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST E8TIMATE
Mai. Ra*. Lavcl: El. 2.170                     Dam Type Earthfih
Inal Capacity: 412 MW A 72 MW
T ANIS COMlUinU. Wve.
M4X-e«
Cost Level:           Jan 44
Unit Pikas
Amount
ft am
No.
DESCRIPTION
Unit*
Local
US I
Foreign
USS
Total
US 4
Quantrlkea
Local
U5t
Fwakgn
US$
Total j
USS |
A: CIVIL WORKS
5.0 DIVERSION WATERWAYS No.2
4.1 Prallminariai
511
MobUisaiicn
LS
15 00
1500
15 DO
455,797 1
1.823,157 '
2,278.964
5.1 2
Land acqulaktion
ha
2.259 82
ooo
2,259 82
0
0
0
0
5.1,3
Silt clearance
ha
1 594 57
6.779 46
8 474 33
0
0
□
0
BuMctM
455.797            1 623,1 B7             2 275 964
6.2            Access Road*
I5.2.1
Road Improvement
km
7 909 37
31 637 45
39546.66
5
39,547
158 187
197734
ls.2.2
New Road
km
17 400 61
69 602 46
87,003 07
0
0
0
0
15 2 3
Stream Crossing
No
22 590 20
90 392 B0
112 991 00
0
0
0
0
Sublolal
39,547
156,157
197,734
4,3 Diversion Intake
531
Earth axesvabon
CU m
0 72
290
3 52
1 575
1 140
4 561
5702
5 32
Rock excavation
cu m
1 61
723
9 04
1,275
2.305
9.221
11 520
533
Masj toner ale
cu.m
IBM
72 31
90 39
2 550
46,099
164.396
230 495
53*          Sliuctoral coocreta
cu.m
2599
103 95 1
129 04
1.350
35 084
140 335
175 410
535
Fofm*wk
m
10 17
40 58
SO 8S
4882
49 650
198 600
248 250
15 3 6
5tc*1 retnlcxcemanl
T
248 58
994 32
1 242 90
r
176
43 750
175 000
218 750
15 3.7
UnmeMiMiKj ftema
%
500
500
500
8 901
35 606
44 507
Subtotal
166.930               747,719               934.646baro-akobo project Inleqrated Maater PUn
TAMS Consultant*. Inc.
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
1.4 5.4 1 5 42 543
Diversion Carta/
Common excavation
Rock excavation
Earth W from borrow
cum
cu m
0 72
181
1 36
290
7 23
5 42
3 62
9 04
0 78
96600
640 000
0
69 938
1.518.720
0
279.754
6,074.080
0
349 692
7,593 600
0
544
545
HauUng FrW ma/erlal
Earth Ml
cu nV km
0 10
045
041
1 81
0.51
2.26
0
0
0
0
0
0
0
0
5 4.6
Lirung concrete
cu m
24 B6
99 43
124 29
18.540
460 867
1.843 469
2 304 337
54 7
Structural concrete
5 4.8
Cu m
25 99
103 95
129 94
0
0
0
0
formwork
•q m
10 17
40 68
50.85
0
0
0
0
540
Sleet rerWorcement
5410
T
244 SA
994 32
1.242 90
783
194.638
778 553
973 191
Unmeasured items
K
500
5 DO
5 00
112.208
448.833
561 041
Subtotal
2.356,372               9.425.488              11.781,860OARO-AK080 nCJKT
Inlegnttd
T MAB CorLkutaacrtw, Wit.
Plan
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Mai. Rar Lev*!: EL 2,170
Dam Type; Earttiflll
Inst. Capacity:   HZ MW & 72 MW
Coat LtvaL           Jan9G
Unit Price*
Amount
Nem
No
DESCRIPTION
Unlit
Local
US I
Fotelgn
USS
7<Hal         1
US I
Ouantklia*
LOCM
USJ
Foreign j Total
USS USS
1.0
B: ELECTRO-MECHANICAL EQU DAMS AND APPURTENANT WORKS
PMENT
1.1
’ewer tdDply Io 1tw dam
L.S
10,000 00
40 000 00
50 000 00
1
10000
40 000
50.000
12
ntihe and Bulkhead Gala* - Low Level Chilli
each
3 000,00
12 000 00
15,000 00
4
12.000
48.000
50,000
13
High Presturt Slide Gales • Low Level Outlet
each
65 200 00
260,000 00
326,000 00
4
260.800
1 04J 200
1,304 000
Subtotal
292,800            1.131,209            1.414.000
2.0             POWER PLANT No.1
21 1                 Power Irfrtl Gate*
tech
2 40000                0 500 00
12 000 00
9
21 600
86 400             1M.OOO
22
Penal ock
T
494 00
1.075 DO
2*70 00
) 660
□20 040
3,230 ISO
4 100 200 I
23
Inlet Valve*
each
74.000.00
566.000 00
740.00000
4
296,000
2 664.000
2 960 000
1 24
Turbines. Governor* *nd Awdbiafy Equipment
each
205 000 00
2.655,000 00
2.PSOOOOOO
4
1.180.000
10 620.000
1 1 600.000
25
Genet slot a and General or AUNilary Equipment
each
336.000 00
3.024 000 00
3 300 000 00
4
1 344 000
1 2 096 000
13 440 000
2.6
P<m< house Crine
L.S
25,000 00
225 000 00
250 000 00
1
25.000
225.0CO
250.000
27
Station Auxilary M«henta*l Equipment
L.S.
151,200 00
1 360 600 00
1,512 000 00
1
151 200
1 360 800
1 512 000
20
StalkMl Aumllary Eliclflcal Equipment
LS.
534,400 00
4 609 600 00
5 344 .000 00
1
534 400
4 809 500
5 344 000
2.9                J Miwn Ti anilorrnetI
each
70 000.00
630 000 00
700.000 00
4
260 000
2 520 000
2 800,000
210               1 Switchyard Equ-txnenl
L.S.
483.800.00
4 352.400 00
4.836,000 00
1
403,600
4 352 400
4 636 OCO
12.11                Unmeatured lie™
10
10
10
513 584
4 201 436
4,715,020
Subtotal
SMt.424            4«.216.79S iltfeS.ZZO
3.0            DI VERSION WATERWAYS No J |XI , IPWerstanlnfltaGatM
------------------- Subtotal
L 2.400 00 |
9&00.00 J _i?,DOOOO [
a| 21,500J _
21,«00
8^400 | 109,000J
16.400            101,000BARO AKOeO PROJECT
TAMS COMiAwtli, Wic.
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Mai. Rea. Level; El.  2.170
Dam Type:              EarthOII
111 MW A 72 MV9
Coat Laval: Jan-M
A
hem No
description
UnH Prices
Local                 Foreign UnHs                   USI                      US I
Total
US 1
Quant It lea
Local
US 1
mount
Foreign
US $
---------- -------------1 Total
US I           1
4.0
B: ELECTRO-MECHANICAL EQU
POWER PLANT No.2
PMENT
4 1                [ Power Inlake Gales
each
2400 00
9 600 00
12.000 00
9
21 600
66 400
108 000
42
Penstock
T
49400
1 976 00
2 470 00
731
361,114
1 444 456
1 805 570
43
Inlet Valves
each
68.000 00
612.000 00
680,000 00
3
204 000
1 636 000
2 040.000
44
Turbines, Governors and Turbine Equipment
each
321 000 00
2 669 000 00
3 210 000 00
3
963 000
8 667 000
9 630 000
45
Generators end Generator Auxiliary Equipment
each
305 000 00
2.745 000 00
3 050.000 00
3
915 000
8.235,000
9.150.000
46
Powerhouse Crane
LS.
25 000 00
225 000 00
250 000 00
1
25,000
225.000
250 000
47
Station Auxiliary Mechanical Equipment
L.S.
106 000 00
972 000 00
1.080 000 00
1
106 000
972 000
1080 000
40
Station Auxiliary Electrical Equipment
L.S.
322 000 00
2 898 000 00
3 220 000 00
1
322 000
2 898 000
3 220 000
49
Main Transformers
each
62 000 00
558 000 00
620 000 00
3
186.000
1 674 000
1 860,000
4 10
Switchyard Equipment
L.S
346.600 00
3,137 400 00
3 486 000 00
1
348 600
3,137.400
3 486 000
411
Unmeasured Items
%
10
10
10
345.431
2917,526
3.262 957
Subtotal
3,799,745
32,092,782
36,892.527
DIVERSION WATERWAYS No.2
| Diversion Inlake Gales
6.0
TRANSMISSION LINES
61
SC 230-kV Tram Line from P P «> to P P 92
62
SC 230 kV Tians Line from P P. II to Gngel Gibe
km
km
35.000 00
140 000 00
175 000 00
15
525,000
2.100 000
2 625 000 1
35 000 00
140 000 00
175.000 00
165
Subtotal
5,775.000
23 100 000
.
28.875,000 /
1,300.000          25.200,000 JI. 500.000DRAWINGS
FOR
GEBA HYDROELECTRIC PROJECTDrawing
list of drawings
Title
GE-1               Project Plan
GE-2               Project Profile
GE-3               Reservoir Plan
GE-4               Geba Dam - Plan
GE-5               Geba Dam - Profiles
GE-6              Geba Dam - Cross-Section and Power Outlet GE-7              Geba Dam - Spillway Profile and Section
GE-8              Power Diversions • Plans
GE-9              Power Diversions - Intakes
GE-10            Power Diversions - Canal Section and Penstocks GE-11            Powerhouse No 1 - Plan and Section
GE-12            Powerhouse No. 2 - Plan and Section. ^-<y x / r\\. c .
(f
- <
Diversion Dam
' 1 
Power Canal -—L
and Intake No. 2 ~
Power Canal
Diversion     Dam and Intake No. I
PROJECT LOCATION MAP
0       200 40Gkm
II1I
SCALE
■?
BOSHA^FO*E5 -
r
MINISTRY OF WATER RESOURCES
ADCMS ABAfiA ETHIOPIA
"I “V-■’■■'■ L__i—7^
TAMS - ULG
MEW YORK - LONDON - ADOS A8 *8*
bafio-akobo master plan prefeasibiuty studies
0
GEBA HYDROELECTRIC POWER PROJECT
PROJECT PLAN
[Dote
■ October 1996
| Dwg No GE - 1ELEVATION in mtters
Gebo Dorr Crest El. 2*75
_____ _Heoowcr«s o' Divers on 7
‘EL 2*2C
Powe' Ccnc 0=51.7m%
1
1
Penstock 3.2®
1
-_________________ t------
1 1
1
!1
C  vers  on  1  Powe-houM
£1. 18*0
/ ‘------------------------------------------- --------
1
________
—V
/
/1
’
1
1
1
Heodwortcs of Diversor 2 .
El 1680
-°o«er Conot Q-51 .Trr>\
D version 2 3owerrouse
/ El :5Q0
ministry of water resources
ADDIS A0ABA ETHIOPIA
TAMS - ULG
- LONDON - ADD!S aBaBa
rT^TaKOBO MASTER PLAN PREFEASIBILIT^ STUDIES CEBA hydroelectric power project
PROJECT PROFILE
October 19S&
[ Dwg Mo GE - ?MINISTRY OF WATER RESOURCES
ADO'S ABABA ETHIOPIA
TAMS - ULG
NEW YORK - LONDON - AQOlS AQABA
BARO-AKOBO MASTER PLAN PREFEASIBIUTY STUDIES
GEBA HYDROELECTRIC POWER PROJECT
RESERVOIR PLAN
Date
| Owg No CE-3Basin
I Spillway Chute W«5 3
2 - 4.2 # Diversion Tunnels 905000 ------------
itake Tower
ministry of water resources
*PP»S ABABA ETHIOPIA
* W Y0WK
TAMS - ULG
LOMDON - ADDIS ABABA
3AR0-AKOBO MASTER PLAN PREFEASIBILITY STUOIF'?
GEBA HYDROELECTRIC POWER PROJECT
GEBA DAM - PLAN
Date • Octotw
|       0*9 *> St -4C Dam
Normal Haxmlmum
Water Level
EL 2170
Crest EL 2175.00
Normal Minimum Water Level
EL 2145|
Coarse Filter
Fine Filter
Rip Rap
Select Earth fill
upstream Shell
2.0 m thick
Filter 2.0 m thick
Impervious Core
Earth-fill Shell
3.0 Stripping
Cort Trench
GEBA-EARTH FILL DAM - TYPICAL SECTION
(, 2-1.83*3.66 Emergency Gates
I 2-1.83m3.66 Se r v Ice Gates
r-f^A
2-2x4 meter
Selective Withdrawal
Gates above . at
EL 2145 and El. 2160
s.o
Access Shaft
3.0 Square
Selective
W ithdrawal
Shaft
2-1.8 x 4.2 Bulkhead Gates
MINISTRY OF WATER RESOURCES
ADDIS ABABA ETHIOPIA
TAMS - ULG
<W TOOK - LONOOH - ADO IS ABABA
baro-akobo master plan prefeasibility studies
GEBA HYOROELECTRIC POWER PROJECT 0AM CROSS - SECTION AND POWER OUTLET
LONGITUDINAL SECTION THROUGjjJ^-^SL SHAFT
| Date
. OcteOar ™ 
| Dvg N« 6€ - 6Max Flood Level EL 2T7Z0 |
EL 2166.0
Grout Curtain
L0 typ (on sloping chute) «
--------------------------------- --------------- O-S0 typ
Anchor bolts a 23 (typ)
0.075 Drain Holts ^>5_q
SECTION TROUGH SPILLWAY CREST STRUCTURE
I
section a - a
ik.2TQ.50
JLM,
25.0
S TIL LI NG BASIN SECTION
MINISTRY OF WATER RESOURCES.
j_____________________A__O_O_t_S__A_B_A__B_A__E_T_H_IOETPHIAIOPIA_____________
TAMS - ULG
NOTE : Drains and Anchors
Same as on Chute
MEV TOOK . IQNCCW . ADC IS A>A>A
SECTION B - B
BffO-AKOBO MASTER PLAN~PREFEASIBILnWmKTc?- f.CHA uvnnAr,             __---- ------------------  w 1
GEB SAPHILYLDWRAOYEPL RECOTFRILICE APONDWSEERCPTRlSOiJsECT
0<»«6«r WPower house
El. 1840
a
Power Cana!
Diversion Dam and Intake No 1
El 2120
?C8>”
X/9000
MINISTRY Or WATER RESOURCES
A DO IS A8ASA ETHIOPIA
TAMS - ULG
XV YOQX - LONDON
A22LS A3 ASA
■x                        & VX SOO ;«< Sraie i So.:iQ
3.v
rte’an
BARO-AKOBO MASTER PLAN PRErEASIBILIT Y STUDIES
GE8A HYCROELECTRIC POWER PROJECT POWER DIVERSIONS - PLANS.
O»t<:       October HU
I Dvg No GE - B
^Zintake Gates
Intake
Structure
Spillway
ELEVATION
UPSTREAM ELEVATION OF SPILLWAY
AND INTAKE STRUCTURE
Scale 1:1000
Concrete Ogee Spillway
and Roller Bucket
Emergency Spillway
Existing Ground
I
Assumed Rock Surface.
V7A
REFLECTED SECTION
Scale 1:200
MINISTRY OF WATER RESOURCES
,________________ ADOIS ABABA FT MIOPIA_______________________________ _______
tams - ulg
"
PLAN
____________________ MEW YORK - LONDON - ADDIS ABABA ________________________________
~9ARolAK0B0 MASTER PLAN PREFEASIBILITY STUDIES GEBA HYDROELECTRIC POWER PROJECT
POWER DIVERSIONS - INTAKES
D»t« ; | October J Qwg No GE - 93 CO.iQ GO
Serv'ce Bay
Transformer
Burned Manifold
Draft Tube Dech
Deck
3.20m O.a
Surface
Penstock
Li—V               Lr~
£ 2BMW unit
i
Trans form er Boy
Generator Hoar -
m
Normol TW Level El 10*0
intake     Valve I 40 ID.
r— t Distributor
MINISTRY OF WATER RESOURCES ADOS A3ASA ETR'CPtA
TAMS - ULG
H£w YORK - L0N00N - ADOS aS aS a
BaRQ-AKOQO MASTER PLAN PREFEASJ&UTY STUDIES
GE8A HYDROELECTRIC POWER PROJECT POWERHOUSE NOJ - PLAN AND SECTXX
Dote
October t996
<5.00*10 00
Service Bay
Transformer —\
9urried
=U"
J20n Dla
Surface
’enstoch
Draft >ube DeO
£ 24MW Generator (T^> )
Generator  Floor —
£ 24MW Unit 1---- 1
Troni'ormer Bay
i
Normal
£ Distributor
MINISTRY OF WATER RESOURCES
ADOS AQABA ETHJCP1A
TAMS - ULG
NEW YORK - LONDON - ADOS ABABA
BARO-AKOBO MASTER PLAN PRSFEASlBnJTY STUDIES
Dote; October 1996
| Dwg No C€ ~ 12APPENDIX 3-1 GUMERO HYDROELECTRIC PROJECT
Detailed Cost Estimatesbaro-akobo project Integrated Master Plan
TAMs
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Max. Res. Level: El.   1.610          Dam Type:               Rockmi Inst. Capacity:   12.2MW. 18.4MW & 21MW
Item
No. DESCRIPTION
Local
Co« Lcvm-
Amount ”
—
Foreign
1.0
A: CIVIL WORKS
DAMS AND APPURTENANT WORKS
2.0          POWER PLANT No.1
3.0          DIVERSION WATERWAYS No.1
4.0          POWER PLANT No.2
5.0          DIVERSION WATERWAYS No.2
6.0          POWER PLANT No.3
7.0          DIVERSION WATERWAYS No.3
4.356,819           17.427 274 577,281            2.309 728,329              2,913 3ir 621.614             2.486 457 548.395             2.193 sat 717.405             2,869 621
1.484.226
5.936,906
TOTAL CIVIL WORKS
9,034,069           36 136 278
,,
B: ELECTRO-MECHANICAL EQUIPMENT
1.0         DAMS AND APPURTENANT WORKS 2.0          POWER PLANT No.1
3.0          DIVERSION WATERWAYS No.1
4.0          POWER PLANT No.2
5.0         DIVERSION WATERWAYS No.2
6 0          POWER PLANT No.3
7.0          DIVERSION WATERWAYS No.3
8.0         TRANSMISSION LINES
TOTAL EQUIPMENT
52.400 1,374,144
1.600 1,798,559
1,600 1.969.537
1,600 884,520
6,083,960
209 600 5.496,577
6.400 7.194.238
6,400 7.878.147
6,400 3,538.080
24,335,842
21.784^ 2118.40
3.841^ 3.100;,. 2741 pi 3.50
Ici.-a _”
■Xi Ma ’WU.rZ
A V.l o.m
8 992 T 8D0C
9.847 tM
!W
4,422a 3O.4U.W2
TOTAL BASIC COST Physical Contingencies         20%
Engineering and Administration         10% TOTAL CONSTRUCTION COST
15,118,030 3,023,606 1,814,164
19,955,799
60,472,119
12,094,424
7,256,654
79.823,198_
IS,1W».
1.CT.N
95£»£.TAMS ConUiRanlE. Enc.
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Mu.Rn L«v*l: EL l.rw Own Typt:                           Rockfil
lMt.Qjp.tfy: 12 2MW 1I4MW4 21MW
fi                         Amount
lie"1
InFSCRIPWN_______________________________________
Local
Foreign
Total
'VCML WORKS
i7"
11
1.2
1.3
1.4
1.5
1.6
1.7
- 55SSAND APPUR 1 tNAN1 WUHK5
preliminaries
Access Roads
Diversion Tunnel
Cofferdam
Rockflll Darn
Spillway (separate from dam)
Low-level Outlet
653,523
79.094
429,760 194,175
2,322,931 651.141
26.194
2,814.091 316.375
1.719,041
776.701
9,291.726
2.604.563 104.777
3.267,614
395.469
2,148.802
970.876
11.814,657
3.255.704
130.972
TOTAL 1.0
4,356,819
17,427,274
21,784,093
10
2.1
22
2.3
2.4
2.5
12.6
2.7
POWER PLANT No.1
Preliminaries
Access   Roads
Power Inlake
Penstock    (surface)
Powerhouse (surface)
Tailrace    Channel
Switchyard
86.592
150.278
42.178
45,104
207,879
0
45,249
346.369
601,112
168.714
180415
831,518
0
180.996
432.961
751.390
210.392
225.519
1.039.397
0
226.245
TOTAL 2.0
577,281
2,309,123
2,886,404
io
3.1
3.2
13
3.4
DIVERSION WATERWAYS No.1
Preliminaries
Access Roads
Diversion Inlake
Diversion Canal
109.249
0
59,563
559,516
436.997
0
238,253 2.238,065
546,247
0
297,817
2.797.581
*.0
41
42
43
4.4
4.5
4.6
4.7
-----
TOTAL 3.0
728,329
2,913,316
3,641,648
POWER PLANT No.2
Preliminaries
Access Roads
Power intake
f’ensiock (surface)
Powerhouse (surface)
Tailrace    Channel ®*ritchyanl
93,242
185,079 42.178 |
46.397
207.468
0
45.249
372.969
740,317
168,714
193,589
829,872
0
180,996
466 211
r
925,396
210.892
241,987
1,037,340
0
226.245
io ~ i
------------ TOTAL 4.0
621,614
2,486,457
3,106,071
’i          i 5-2 *
?1
54 L
=^ERsioNWAT S N .2
ERWAY        0
summaries
^ss Roads
aversion Intake
Version Canal
82.259
0
59,563
406,573
329.037
0
238,253 1.626,290
411.296
0
297.817
2.032.863
------- ---------
TOTAL 5.0
548,395
2,183,581
2,741,976BAROAKOBO     PROJECT Integrated Master PUn
Item
No.
DESCRIPTION
gumero hydroelectric PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Max. Ret. Laval: El. 1.410 Dam Type:                         Rockfill
ln>t Capacity: 12.2MW. 1S.4MW & 21 MW
q
430,443
1.233 862
168 714
193 589
694^006
n
149.007
Local
6.0
6.1
6.2
6.3
6.4
6.5
66
6.7
POWER PLANT No.3
Preliminaries
Access Roads
Power Intake
Penstock (surface)
Powerhouse (surface)
Tailrace Channel
Switchyard
Amount
Forei n
-------
TOTAL 60
107.611
308.465
42,178
48.397
173.501
0
37,252 717 405
1542^
210.H
24, .sr 867io?
1K2S
7.0
7.1
7.2
7.3
7.4
DIVERSION WATERWAYS No.3
Preliminaries
Access Roads
Diversion Intake
Diversion Canal
Z o69 621
ff
222.634
0
80,501
1.181,091
890.536
o
322,004
4.724.366
1.113.1D
1
5,905.45?
TOTAL 7.0
1.484.226
5,936,906
7,421,1).’
ITAMS
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Mm. R« Lew* EL 11 m D*nT\p», RacUSir
tost Cftpaerfy: 1I2MW, 1L4MW171 MW
-
nPSC R OPTION___________________________________
^ELECTROMECHANICAL equipment
■^iSAND APPURTENANT WORKS
Power supply f0 lh® dam
intake  and  Bulkhead  Gates  -  Low  Level  Outlet High pressure Slide Gates - Low Level Outlet
TOTAL 1.0
|_____________ Oori LevtL Jjn-W
|_____ Amounl
Local
Foreign
Total
10.000
3.200
39,200
52 400 | '
1,800
154,622
44,000
232.000
40.000
12,800
156.800
209,600
6.400
618.466
176.000
928.000
50,000
16.000
196.000
POWER PLANT No.1
Power Intake Gales
Penstock
Intel Valves
Turbines. Governors and Turbine Auxiliary Equipment Generators and Generator Auxiliary Equipment
Powerhouse Crane
Station Auxiliary Mechanical Equipment
Station Auxiliary Electrical Equipment
Main Transformers
Switchyard Equipment
Unmeasured Items
__________________________________ TOTAL 2.0 DIVERSION WATERWAYS No.1
Divert on Intake Gates
336.000 45,000
1.344.000
180000
69.000
276,000
181,000 76000
724,000
304.000
110.000
124.922
440.000
499.689
TOTAL 3.0
POWER PLANT No.2
Power intake Gates
Penstock
Inlet Valves
Turfxnes, Governors and Turbine Auxiliary Equipment Generators and Generator Auxiliary Equipment
Powerhouse Crane
Station Auxiliary Mechanical Equipment
nation Auxiliary Electrical Equipment
Mam Transformers
witchy and Equipment
unmeasured Items
- ------------------------------------------------- TOTAL 4.0
TOTAL S.0
1,374,144
1.600
1.600
1.600
168.454
52.000
294,000
508.000
45.000
73.000
281,000
112.000
120.000
163.505
1,798,559
1.600
1,600
5,496,577
6.400
M00
6.400
673,816
208.000
1,176,000
2,032.000
180.000
292.000
1,044,000
448.000
480.000
654,022
7,194,238
6.400
B.OOO 773,110
220.000
1,160,000
1.680,000
225.000
345.000
905,000
380.000
550.000
624,611
6,870,721
B.OOO 8,000
D y/^ioNWATERWAYS No.2
Dive^on Intake Gates
"
8,992,797 6,000 6,000baro-akobo project Integrated Master Plan
TAM$c*h^
[Item
No. DESCRIPTION
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Max. Res. Level: El. 1,610 Dam Type:                             Rockfill
Inet. Capacity: 12.2MW. 1B.4MW & 2mw
—            c<*tLew
_ Amount^"
Foreian 1
—2jMt
Local
6.0 6.1 62
6.3
6.4
6.5
6.6
6.7
6.8
6.9
6.10
6.11
POWER PLANT No.3
Power Intake Gates
Penstock
Inlet Valves
Turbines, Governors and Turbine Auxiliary Equipment Generators and Generator Auxiliary Equipment Powerhouse Crane
Station Auxiliary Mechanical Equipment Station Auxiliary Electrical Equipment Main Transformers
Switchyard Equipment Unmeasured Items
1,600
173,888
6,400
695 552
56,000               224 000
334,000
552,000
45.000
75,000
1.336,000
2,208,000
180.000
300 000
1
300,000            1.200 000
128.000               512 000
125,000               500,000
179,049               716.195
280 COj
67$ GOq
.
22S,ax
375OQC
1,500.001
6«Mc
62SCCC
895244
TOTAL 6.0
7.0
7.1
1,969,537            7,878,147 i
DIVERSION WATERWAYS No.3 Diversion Intake Gates
1.600
6.400
TOTAL 7.0
1,600
6,400
8.0
8.1
8.2
8.3
TRANSMISSION LINES
Transmission Line 132-lcV from Gumero No.1 to Gambela-Gore Transmission Line 132-kV from Gumero No 2 to Gumero No.1 Transmission Line 132-kV from Gumero No.3 to Gumero No.2
294.840 1,179,360
189.540 758.160
400,140 1.600.560
TOTAL 8.0
884,520            3.538,080
loot i.o::
1.474JM
94770)
2,000 ^0
4,422 WLH4ftOJ
totegrafed Mesfer Men
GUMGRO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Maw. Re*. Laud: El. 1.110
Dam Type:
^OCklUI
Inst. Capacity: 12.2MW. 11-4MW &21MW
Coitlrrtl
Jwi4«
Unit Pries*
Amount
\
Item
No.
DESCRIPTION
Units
Local
US *
Foreign
US I
Total
US|
Quantities
Local
USS
Fowlgn I        Total         I USS                     USS         |
6.0
B: ELECTRO MECHANICAL EQUIPMENT
POWER PLANT No.3
8.1
Power Intake Gales
each
MO 00
3,200.00
4.0W0C
2
1.600
6.400
8.000
62
Pemtock
T
494 00
1976 DO
2,470 00
352
173.088
695,552
869 440
63
Inlei Valves
each
26 000 00
112000 00
140.000 00
2
56.000
224.000
280.000
64
Turbine* Governor* and TtrMna Auxiliary Equipment
each
167.000 00
668,000.00
835,000 00
2
334 000
1,336,000
1 670 000
6.5
Gerwalors and Generator AmuLary Equipment
each
276000 00
1,104 000 00
1 ISO 000 00
2
552.000
2 208 000
2 760 000
6.6
PowertioLrse Crane
L.S
45 000 00
100 000.00
225 000 00
1
45,000
100 000
225.000
87
Station Amikaty Mechanical Equipment
L.S.
75,000.00
300000 00
375,000 OO
1
75 000
300 000
375 000
66
Station AunUery Electrical Equipment
LS
300 000 00
1,200 000 00
1,500 000 00
1
300 000
1 200 000
1 500 000
8fi
Main Transformer*
each
64,000 00
255,000 00
320 000 00
2
126 Ooo
512000
640 0Q0
6 10
Switchyard Equipment
L.S
125.000 00
500.000.00
625 000 00
1
125 DOO
500 000
625 000
6.11
Unmeasured Item*
%
10
10
10
170.049
Subtotal
---------- r----------4' ■
7,171,147------------ 1,147,414
718 1W
AQA 74a 1
7.0            DIVERSION WATERWAYS No J __________ ______ ________ __________ ___________ ___________
|Tl
lo^rsipn Ini sks Gates
|aach
|
800 00 |             3.200 00 ]              4.DOG 00 |
Subtotal
1^69^37 2 | I 600 J
1600
e,4oo |
a poo ]
MW                     n.oooBARO-AKOBO PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultanta, Inc.
01-Doc-M
Res. Level: El.   1.610
Inst. Capacity:
Dam Type:
Rockflll
12.2 MW. 1I.4AIW A 21MW
1
Unit Prices
Amount
DESCRIPTION
A: CIVIL WORKS
1.0 DAMS AND APPURTENANT WORKS
1.1 Prellmlnarlee
Local
1 US $
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign                Total USS                    USS
1 Mobdizaton
%
1500
1500
1500
653 523
2.614 091
3 267.614
Il 1 2          1 Land acquisition
ha
2,259.62
0 00
2259 82
0
0
0
0
|f.1.3         | Site clearance
ha
1,694 87
6 779 46
8 474 33
0
0
0
0
Subtotal
653.523            2.614,091            3,267,614
1.2 Access Roads
1 2.1
Road Improvement
km
7 909 37
31,637 48
39 546 85
10
79.094               316.375
395,469
1.2.2
New Road
km
17.400 61
69,602.46
87.00307
0
00
0
123
Stream Crossing
No
22 598 20
90.39280
112 991 00
0
00
0
Subtotal                                                                                                                                                 79094               316.375               395.469
1.3            Diversion Tunnel
1.3.1
Portal excavation
cu m
1 36
5 42
6 78
2 000
2.712
10,848
13 560
132
Tunnel excavation
cu m
10.17
40 68
50 85
7 950
80.852
323.406
404 258
1.3 3
Tunnel support - rock boils
T
1.355.89
5,423 57
6,779 46
20
27 660
110 641
138,301
134
Tunnel support - shotcrete
sq m
5 65
2260
28 25
690
3,898
15 594
19 493
1.3 5
Tunnel support - arches and riba
T
451 96
1 807 86
2,259 82
0
0
0
0
136
Concrete lining
cu m
40 6B
162 70
203 38
2.450
99 656
398.625
498 281
1.37
Structural concrete
cu m
25 99
103 95
129 94
o|
0
0
0
II.3 6          1 Formwork
sq m
10 17
40 68
50.85
5500 1                55 935
223 740 /               279 675
U3 9
ixiMo< cement
T
248 58
994 32
1.242 90
319 /                79 297
317188 T               396 485 1
\\ 3 10        \ Drilling tor grouting and dfins
.
m
15 82
63 27
70 OO
2 025 /                32 031
\CJtOM<mo
T
11299
451 97
564 96
27,254
128 126 I
109 015 1
U
5 OO
6 OO
O OO
BuMoUl
Jz
2O4ft5 J m eso [
7f\O
160,157 1
136 266 7
1O7J24 /
ao:BAKtWiMQ PKOJEGT MfOfttfd JWMlar
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
M
141
Coffardarr
Foundalion eccivatwi - Common
cum
072
290
362
26,700
19 331
77 323
96 654
142
Foundation eucaYibon - Rock
cum
1.61
723
9.04
0
0
0
0
1.43
Borrow •■cwitton - Earth
cu.m
066
271
3 39
132.200
89632
356.526
448,158
t44
Borrow sxewalion - Rock
cum
096
364
4 80
7000
6.720
26 880
33.600
1 45
Hauling (!■ malerial |W?r 2 km)
cu rrVkm
□ TO
041
0 51
0
0
0
0
146
Unproortaed PH (placemen!)
cu m
045
1.81
2 26
132,200
59 754
239,016
296 772
1.4 7
Processed IHI (piacerr^nl)
cum
1.36
542
8 78
7000
9 492
37968
47 460
146
Unmeasured i’cRi
%
500
500                   500
9.246
36.966
46,232
Subtotal
194,175
776,701
970.876
1.6           Rockfill Dam
1 51
FoundaiLon ewcavallon - Common
cu m
0 72
2 00
362
221 580
160 424
641 696
602,120
IS 2
Foundation oxcavabon - Rock
cu m
1 61
7 23
9 04
45 580
82.400
329.635
412,043
1.6 3
Borrow excavabon Earth
cu.m
066
271
3 39
0
0
0
o
1.54
Barrow excavaflion * Rock
cum
0 96
3 84
460
478 1D0
456 976
1 835 904
2.294,880
1 55
Hauling fill malarial [war 2 km)
cu.m/krn
0 10
0 41
0 51
0
0
0
□
156
ImpervXHja cor®
CU m
2 26
904
11 30
202,390
457 401
1 629 606
2 287 007
1 5.7
Rockllk (placement}
cu.m
0 86
2 71
3 39
*88.330
331 086
,
1.324 351
1 58
1 655 430
Filar*
cu.m
3 39
1356
16.95
21 960
74 444
,
297 77B
372 222
159
Drama IranaMlOft*
euLm
3 39
1356
18 95
135.030
457 752
1.831 007
1.5 10
R*p-rap (ptacamanl)
cu.m
2.288 7S9
1.13
4.52
565
25 590
26 917
115 667
1 5 11
Drifting lor gna/ing and drama
m
14*1 504 '
11.30
45 20
56,50
5,720
64,636
258 544
1.5.12
32J 160
Grouting
T
112 W
451 97
564 95
682
96,269
385 077
481 J48
15 13
Unmaaeured lams
i
500
500
5 00
110,618
442 463
Subtotal
S53 079 1
2.322 931              9,291,725           11.614 657BARO-AKOBO PROJECT Integrated Mester Plan
TAMS Consultants, Inc.
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Max. Rm. L«vrt: El. 1,«10
Dam Type:        RockfSB
1------------ i
litem
1 DESCRIPTION
A: CIVIL WORKS
1.6 Spillway (separate from dam)
Bu* excava Iron - Common
Init. Capacity: 1MMW, 1I.4MW & 21MW Cort Lava):
Unit Prices
Amount
Units
Local
USS
Foreign
USS
Total
Local
USS           Quantities               USS
Foreign
US s
Total
US S
161
cu m
0 72
290
362
180.000
130.320
521,280
651,600
1 62
Bulk excavation - Rock
cu.m
1.81
723
904
80 400
145.363
581 453
726.816
5 63
Slruclural excavation * Rock
cu.m
452
1806
2260
0
0
0
0
1 64
Maas concrete
cum
1808
72 31
90 39
12 555
226.969
907 877
1,134 846
165
Structural concrete
cu m
25 99
103 95
129 94
510
13.254
53.016
66,269
168
Formwork
»q m
10.17
40 68
50 85
7.430
75 563
302,252
377,816
167
Sleel reinforcement
T
248 58
994 32
1 242 90
30
7 457
29 830
37.287
168
Drilling lor drains
m
11 30
45 20
56 50
1,200
13560
54.240
67.000
169
Drilling for grouting and drams(from gall)
m
15 82
63 27
79 09
40
633
2531
3,164
1 610
Anchors (including drilling and Grouting)
m
2,982 96
11,931 85
14,914 81
22
6,563
26.250
32,813
1 6.11
Grouting
T
112 99
451 97
564 96
4
452
1 808
2260
1.6.12
Unmeasured Hems
%
500
500
500
31.007
124.027
155,034
Subtotal
651141              2,604.563             3.255.704
1.7           Low4eve1 Outlet
1,7.1
1.7.2
1.7.3
Portal excavation
Tunnel excavation
Shah excavahon
Tunnel support - rock bolls
cu m
cu m
cu m
°1
°1
0/
174
T
1 7 5      \T unnel support - shotcrete
sq m
\1 7 6 llunnel support - arches and rib*
H.7.7       \ Lining concrete
\i.n      \Slructurat concrete
\M *
T
cu m
1.36
1017
1808
1 355 89
565
4S1 96
40.68
25 DO
542
40 68
72 31
5.423.57
22 60
1.807.86
162 70
103 05
4OM
W4M 32
6 76
50 85
90 39
6.779.46
20.25
2,259 82
203 38
12994
so as
1.242 DO
0
0
0
0
0
0
0
0
0
0
0
0
0
0
a 523
0
0
0
0
0
0
0/
0/
01
0 /
0/
cu m
■q.m
\\ 7 W
'eUMaicemerA
1o<
10 17
24a sa
’ • -
_ too
251
1 OO5
33
10221 ,
«.2oj /
---------- ^7“
2*092 1
40 043 1
32,91-7 /
32 015 /
51 104 /
41 ore /
1W
and O>a*r>«
Av--------
in
aa 37
70 oo
O
9 OO
n t”' ,
o
-----1 _
---------
V o 1
*» ✓ ° /
/PftOJZCT
folrgrtM MtstorPlin
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Ttoe.
Mn Ret. Laval: El. 1(10
Dan Type: RocklN
Inal, Capacity; 11JMW. 10.4MW 4 21MW
Cortlevat.
k                      Unit Prices
Local           Foreign             TcHal
USS               USS                  USS
Amount
Lm /
/No, JDCSCRAPTION
I
Units
OuanlUits
Local
USS
Foreign                local USS                     uss
A: CIVIL WORKS
2.0 POWER PLANT No.1
2,1 Prellmlnarlea
2.1 1
Mobilization
L.S
1500
1500
1500
M592
344,369
432.961
2.1.2
Land acqula4*on
ha
2.259 32
000
2,25942
0
0
0
0
2 13
Site dearance
ha
1.6W.57
6 779 46
B 474 33
0
0
0
0
06.592               340.369               432.961
2.2            Access Roads
22.1
Read Improvement
km
790937
31.537.46
39 546 05
8
63275
253 100
318 375
222
New Road
km
17 400 61
69,002 46
87.003.07
5
57 003
348012
.
435.015
2.2.3
Stream Crossing
Nd
22 596 20
90.392 M
112.991 00
0
0
0
0
Subtotal
150278
801.112               751.390
2.3 Power intake
23 1 Eerlh wwcsvartOT
gu m
0 72
290
3 52
HO
60
319
398 1
2.3 2
R<xk eMtivailon
cu m
1 61
7 23
904
0
0
0
0
233
Lining concrete
cum
4068
162 70
203 35
0
0
0
0
2 3.4
Structural concrete
cu.m
25 99
103 95
129 94
450
11 695
46,778
50,473
23 5
Formwork
eq m
1017
40 85
50 65
1 350
13730
54916
68.648
236
Slecl rekifo/cinien!
T
245 58
994 32
1,242 90
SB
14 666
58 685
73.331
23 7
Unmceaured Hems 2 006
Sublets!                                                                                                                                                42176
i
500
5.00
5 00
5.034
10042
IM.714                210.092
941
nnwui.ii put iMfcwj                           _ __        __ Common excavation
cu.m
072
Z.BO
3 62
2400
1.736
6 950
3 688
947
Rock picavadten
cu.m
1.81
723
904
250
452
1 608
2 260
243
Anchor bolls
m
1356
tunR
S4 23j 72 31
67.79
0 250
0
4520
0
16 07B
0
22 595
2.4 4
245
246
2.47
248
Masa concede
Structural concrete__________________________ Formwork_________________________________ _ Steel reinforcement__________________________ Ufimeaaurad Mam*___________________________
cu.m
cu m
sq.m
T
%
25.99
1017
246 56
1000
103 95
40 68
$94 32
1000
129 94
5085
1.24290
10.00
250
2 000
30
6497
20340
7,457
4.100
45,104
25 955
81 360
29.830
16401
160.415
32 485
101,700
37,267
M.5O2
225,519BAR0-AK060 PROJECT Integrated Matter Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultants, Inc.
OI-Dec-88
Mai. Rae. Level: El.  1,815
Inst. Capacity:
Oam Type: RockfWI
12JMW, 1I.4MW A 21 MW
Cost Level:          Jan-81
1
Unit Prices
Hem
No.
DESCRIPTION
Units
Local
US 1
Foreign
USS
Tolal
USI iQuanfitiaa
Local
USS
Foreign
USS
Tolal
USS
2.5
2.5.1
A: CIVIL WORKS
Powerhouse (surface)
Common excavation
cu m
072
2 90
362
6 300
4 561
18 245
22 806
252
Rock excavation
cum
1 81
7.23
904
4.780
8.642
34 569
43.211
253
Earthfill
cum
0 45
1 81
226
3,900
1763
7,051
8814
254
Masi concrete
cu m
18 08
72 31
90 39
1.036
18.729
74 915
93,644
2 55
Structural concrete
cum
25 99
103 95
129 94
976
25.364
101.457
126 821
256
Formwork
sq m
1017
40 68
5085
2990
30 408
121 633
152.042
25.7
Sleet reinforcement
T
248 58
994 32
1.242 90
198
49 219
196,875
246 094
256
Roofing
sq m
180 79
723 14
903 93
162
29 287
117 149
146 437
259
Blockwork
sq m
904
3616
45 20
324
2 929
11,716
14 645
2 510
Miscellaneous Metalwork
T
723 14
2 892 57
3 615 71
25
18.079
72,314
90.393
2 511
Slope Protection
sq m
4 52
1806
22 60
0
0
0
0
2512
Unmeasured Hems
%
10.00
1000 |              1000
18898
75 593
94 491
Subtotal
207.879
831,518             1,039,397
2.5
Tailrace Channel
261
Common excavation
cum
0 72
290
3 62
0
0
0
0
262
Rock excavation
cu m
1.81
723
904
0
0
0
0
2.6.3
Unmeasured Items
%
500
500
500
0
0
0
Subtotal                                                                                                                                                       0                           0                           0
2.7 Switchyard
27 1       1 Common excavation
cu m
072
290
362
8,100
5864
127 2       I Rock excavation
23 458 1               29.322 1
cum
1 81
723
904
0
12 7 3      I Foundations and ducts
0
01                                 0/
sq m
124 29
497.18
621 45
220
27 344
I Surfacing
109 375 /             138 719 /
V-
\2 7 5        ^Unmeasured l»mi
22
sq m
1.47
5 87
7 34
5400
7 927
31 709 /                      39 636 /
%
1000
1000
1OOQ
4.114 /16454 /
20 588 /
45,240
180.990
226.245BA/9OJIK0OO FftOJEG T
TAMO CQni’M'.ltMl, taw.
frifegraJecf
Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Maa. Rh Level. El. 1.610
Dam Type: Rockflli
ktft Capacity: UJMW, 11.4 MW < 21MW
Cott Level'. Jan-96
Unit Prkea
Amount
3,0
DESCRIPTION______________________________
A: CIVIL WORKS
DIVERSION WATERWAYS No.1
UnMa
Local
USS
Foreign
USS
Total
USS
Quantlllee
Local
USS
Foreign
USS
Total
USS
3.1 Preliminaries
3.1 1 MobUiutoo
LS
15 00
1500
1500
109.249
436 997
546,247
3.1 2
Land •■cqulallob
Ire
2,259.82
000
2.259 82
0
0
0
0
31 3
Site cle ounce
ha
1.694 87
8,779 46
8,474 33
0
□
□
0
Sublolal
IM 249
436,997
546,247
1.2            Acceaa Roads
321
^oemJ ImprovernenA
km
7,909 37
31 637 46
39 546 85
0
0
0
0
324
New Roed
km
17 400.61
69 602 46
87 003 Of
0
0
0
0
3 25
Stream C-f<?3^ing
No
22,598 20
90 392 00
r
112,991 00
0
Q
0
0
Subtotal                                                                                                                                                           0                           0                           0
34            Diversion Intake
33 1
Earth cMca. Jlion
cu m
0 72
2 90
3 62
503
364
1.457
1,621
332
Rock excavation
cu m
1 81
723
9 04
393
711
2 542
3 553
3 33
Maia concrete
cu.m
10 08
72 31
90 39
786
14,209
56,837
71 047
3 3.4
Structural concrete
cu.m
25M
103 95
129 94
450
11 695
48 778
58,473
3.3.5
Formwork
sqm
10 17
40 68
50 05
1,48J
15 082
60 328
75 411
330
Steel reinforcement
T
240 56
904 32
1.242 90
59
14 666
SB 66S
73 331
3 37
Unmet aured Meme
|%
500
500
500
2036
11 345
14 182
Subtotal
59563                736,253                297.8178ARO-AKOBO PROJECT integrated Mister Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS ConeuManls, Inc.
01-Dec-88
M«x. Rm. Levwi: EL 1.810
0*m Type: Rocklin
Ind. CepecMy: 112MW. H.4MW& 21MW
Coal Level:            Jen-M
1
Item
No.
Unit Prices
Local              Foreign               Total
DESCRIPTION
UnMs                USS
USS                   USS
Quantities
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
3.4 Diversion Canal
34 1 Common excavation
cum
0.72
290
3 62
18200
13177
52.707
65 884
342
Rock excavation
cu.m
181
723
904
167.700
303.202
1.212 806
1.516008
343
Earth Hi From borrow
cu.m
1.36
5 42
6 78
0
0
0
0
3.44
Hauhng HI material
cum/km
010
0.41
051
0
0
0
0
34 5
Earth M
cu.m
0.45
181
226
0
0
0
0
3.4.6
Lining concrete
cum
33 90
13559
169 49
5030
170 507
682,028
852535
347
Structural concrete
cu.m
25 99
103 95
129 94
0
0
0
0
348
Formwork
eq m
1017
4068
50 85
0
0
0
0
3.4 9
Sleel reinforcement
T
248 58
994 32
1,242 90
185
45,987
183.949
229 937
3.4.10
Unmeasured Items
%
5.00
500 |                 500
26.644
106 575
133.218 |
SuMotol
559.516              2.238,065              2.797,581SMO -AKO0O PROJECT intugfMtd Maslttf Pftn
TAME, CumJiiuAlB.'nt'*,, Iww,
GUMERQ HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Maa. Res. Level: El. 1.S10                   Dam Type: RockfUl
Inst. Capacity; 12.2MW, 1I.4MW4 21MW Cost Lwel;
Unit Prices
Jan 46
Amount
Item
No.
DESCRIPTION
Units
Local
USS
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign
US 1
Total
USS
A: CIVIL WORKS
4.0 POWER PLANT No. 2
4-1 PfgUfT^narie*
4 1.1
htobikzalion
LS
1500
1500
1500
84.894
339 577
424 471
4 12
Land scqufoitai
ha
2 250 82
000
2 259 82
0
0
0
,
0
413
Site clearance
ha
1 694 87
5,779.46
8,47433
0
0
0
0
Sub lot ai
64.894
339,577
424,471
4.2            Access Roads
4 2.1
Road Improvement
km
7 909.37
31 637 46
39.546 85
8
63 275
253 100
316 375
422
New Road
km
17,40061
69 602 46
37 003 07
7
121,604
407 217
609 021
423
Stream CroBsirvg
No
22 596.20
90 392 60
112,991 00
0
0
0
,
0
SubloLal
185.079
740.317               925 396
4J             Power Inlake
43 1
Earth excavation
cu.m
0.72
2 90
3 62
110
60
319
308
432
Rock encavalNXV
cu m
1 81
7 23
9 04
0
0
0
0
>433
Lining concede
cum
40 68
162 70
203 38
O
0
0
0
4 34
Structural concrete
cu m
25 99
103 95
129 94
450
11 695
40.770
58 473
4,3 5
Formwork
»q.m
ID 17
40 86
50 05
1 350
13,730
54 910
56 646
4 36
Staci r«nforcemenA
T
248 58
994.32
1,242 90
»
14 666
50 ,WS
73,331
43 7
Unmeasured Hems,
%
500
5.00
5 00
2005
6 034
10042
Subtotal
108,714               210.892
4.4            Pcnttock (aurfacej
44 1
442
4.4 3
444
. 446
.,
445
Common excavation
Rock excavalton
Anchor bolts
Mass concrete
Structural concrete
.
cu.m
cu m
Hl
cu m
cu.m
sq m
4 4.7
T
072
1 61
1356
1606
25 99
1017
240 58
290
7 23
S4 23
7231
103 95
40 68
994 32
362
904
57,79
90 39
129 94
50 85
1.242 90 ,
2.400
260
0
500
0
2000
50
42,178
1 738
452
0
9,039
0
20.340
12429
8 950
1.808
0
36.156
0
81,380
49 716
8666
2,260
0
45 J 95
0
101,700
62.145
4 4 8       [ Unmeasured Items
%
1000
1000
10 00
4400
17 599
21,999
SuMotM
48.397               193.589               241 9878AR0-AK0B0 PROJECT
Integrated Matter Plan
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
1,618                 Dam Type:        Rockfill
: 12JMW, 18.4MWA21MW
TAMS ContuMaMt. Inc.
• 1-0ec-M
Cort Level:           Jan-8 6
Unit Prices
Item
No.
DESCRIPTION
UnMa
Local
USS
Foreign
USS
Total
USS ^OuaiMitiea
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
4.1
4 5.1
cu.m
072
290
362
7 800
5.847
22 589
28.236
45 2
cum
161
723
904
4 230
7.648
30.591
38 239
453
Earth (Ilf
cum
045
1 81
226
2 870
1.297
5.189
6.486
4 54
Mass concrete
cu.m
18.08
72.31
90 39
1.036
18.729
74,915
93 644
455
Struclu'al conccete
cu m
25 99
103 95
12994
976
25.364
101 457
126821
456
Formwork
sq m
1017
40 68
50 85
2.990
30 408
121 633
152 042
45.7
Sled reinforcement
T
246 58
994 32
1 24290
198
49219
196,875
246.094
450
Roofing
eq m
180 79
723 14
903 93
162
29 287
117 149
146 437
45 9
Blockwork
sq m
904
3616
45 20
324
2.929
11 716
14,645
4.5.10
MiecelaneoiA Metalwork
T
723 14
2892 57
3.615.71
25
18079
72 314
90 393
45 11
Slope Proteclion
sqm
4 52
1808
22 60
0
0
0
0
4512
Unmeasured Seme
M
1000
10 00 j               10.00 I
18 861
75.443
94 304
Subtotal
207.468
829.872             1.037.340
4.4
Tailrace Channel
46 1
Common excavalion
cum
0 72
290
362
0
0
0
0
462
Rock excavation
cu m
1 81
723
904
0
0
0
0
463
Unmeasured Items
%
500
500
500
0
0
0
Subtotal
0
0
0
4.T
Switchyard
Common excavation
cum
0 72
290
362
8 100
5 864 |                23 458 |              29.322 /
14 7 2        Rock encBvetlon
cum
1.61
7 23
904
0
0I
1 Foundations and ducU
sq m
124 29
497 16
621 45
220
\SurtacvtQ
27.344 I                109 375 I                  136.719 /
sqm
1 47
5 87
7 34
5 4OO
\4.7S
7 927 I                   31.709 /
39 636 /
%
1000
1OOO
1000
4 114 1                   16 454 /
Subtotal
20 566 /
45.249
100.990
226.245BAKOM OSO PROJEC T tniigrrted Matter Plan
GUJWERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Mai. Rea. Level: EL 1318
DamTypa:         Rockflll
toil Capacity: 111MW. 1t.4MW 821MW
Cott Livtl:              Jan 86
1-----
Unrl Frket
('
Amount
)
Ittam
|No
Local
US 6
For sign
US 6
Total
Local
DE5CRIPTOW
UnMi
US I           QuanUtkei |             USI
Foreign
USI
Total |
us t
A: CIVIL WORKS
5.0 DIVERSION WATERWAYS No.2
6.1 PreBmifwIaa
51.1          MoWllaation
L.S
15 00
1500
1500
82 2S9
329,037
411.296
51 2
Land acquiaulon
hi
2.259.02
000
2.259 82
0
0
0
0
5.1 3
SMe clearance
hi
T, 694.87
6.779-MJ
6,474 33
0
0
0
0
Subtotal
62,259
326.037
411.296
6,2 Acceai Roads
5.2.1
Road Improvement
km
7,909 37
31 637 48
39 546 55
0
0
0
0
522
New Road
km
17 40061
69 60Z46
57 003 07
0
0
0
0
5.23
Stream Crossing
No
22 598 20
90 392 BO
112.991 00
0
0
0
0
Subtotal                                                                                                                                                           0                           0                           0
5.3           Division intake
53 1
Earth ewtavanon
cu m
0 72
2.90
362
503
364
1.457
1,821
53 2
Rock ejuzavllwn
cu m
1.81
7 23
904
393
711
2,842 i
J.553
53 3
Mass concrete
cu m
1806
72.31
90 39
766
14,209
56 037
71 047
53 4
Structural concrete
cu.m
2599
103.95
129 94
450
11 895
445,778
58.473
5 35
Formwork
sq.m
10.17
40.88
50 85
1 483
15 082
60 328
75.411
538
Sleel reinforcement
T
248 58
994 32
1,242 90
59
14.666
58 585
73 331
537
Unmeaavred Hems
%
500
500
500
2.636
11,345
14.182
Subtotal
59 563                238.253                297,817BAROAKOflO PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Max. Rea. Level: El. 1.810                    Dam Type: RocHIHI
TAMS Consultants. Inc.
01-OC-9C
Inst. Capacity: H.2MW. 18.4MW 4 21 MW Cost Level:                                                                                           Jan-88
Unit Prtcei
Amount
Hem
No.
DESCRIPTION
]       Units
Local
USS
Foreign
US 1
Total
Local
USS          Quantities |             USS
Foreign
USS
Total
USS
A: CIVIL WORKS
8.4 Diversion Canal
54 1 Common excavation
cujn
072
290
362
13.800
9 991
39,965
49.956
542
Rock excavation
cum
1.81
723
904
128 800
232.870
931.482
1.164.352
543
Earth fill from borrow
cum
1 36
542
6 78
0
0
0
0
544
Haubng fill material
cu nV km
0.10
041
051
0
0
0
0
545
Earth nil
cum
045
181
226
0
0
0
0
546
Lining concrete
cu m
24 86
99 43
124 29
4347
108,058
432 231
540.289
5.4.7
Structural concrete
cum
25 99
103 95
129 94
0
0
0
0
548
Formwork
sqm
1017
40 68
50 85
0
0
0
0
549
Steel reinforcement
T
248 58
994 32
1.242 90
146
36,293
145171
181 463
5410
Unmeasured fems
%
500
500
500
19 361
77.442
96,003
Subtotal
406.573             1 626.290             2.032.863baro-akcwo pro sec t irrttQfJrtrd JWaafer P/an
T AM* C«nsutMli Ww.
r
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Mjjl Res. Level: El.  1,610
Inst. Capacity;
Dam Type:
RocklW
12.2MW, 1I-4N IW4 21MW
Cost Level:         Jan-81
Hull Pflcee
Amount
Ham
No.
□escnrooN
liniia
Local
USI
Foreign
USI
Total
US |
Qu anil Ila a
Local
USI
Foreign
USI
Total
US|
6.0
6.1
A: CIVIL WORKS
POWER PLANT No.3
PreUminarlae
61.1
MobUtealton
IS
15.00
1500
IS.OO
107,611
430 443
538 054
612
Land rcquiiiiion
ha
2 259.62
000
2259 82
0
0
0
0
6 1,3
SMe ctearance
ha
1.894 87
8.779 46
8,474.33
0
0
0
0
Subtotal
107.611
430.443
538,054
6.2
Accaaa Road*
621
Road Improvement
km
7,90® 37
31 637 48
30,546 85
17
134 459
537 837
672 296
52 2
Naw Road
Um
17400.61
69 602 46
87,00307
10
174.006
696 025
870.031 .
523
Stream Creating
No.
22 598 20
90.392 80
112 991 00
0
0
0
0
WB.46S             1233,062              1.542,327
6,3 Powtr Intake
6 3,1
Earth <xCMlio»i
cu.m
0 72
2.90
3 62
110
BO
319
398
6 32
Rock excavation
cu m
1 Bl
7 23
9 04
0
0
0
0
6.3 3
Lining concrete
cu.m
40 66
162 70
203 38
0
0
0
0
6.3.4
Structural concrete
cxi m
25 99
103 95
129 94
450
11 595
46 776
58.473
8.3.5
Formwork
sq.m
10 17
40M
50 85
1 350
13 730
54 916
68 648
6.3 6
Steel leirloccement
T
248 56
994 32
1 242 90
59
14,650
58 665
,
73 331
6 37
Unmeasured llama
%
500
500
5 00
2.006
a 034
10 042 |
Subtotal
42.176
166,714               210092
6.4 Pcnalock (surface]
641
Gammon excavation
CU m
0 72
2.90
3 62
2400
1,736
6.950
8686
642
Rock axcavalwi
cu.m
1.81
7.23
904
250
452
i.eoa
2 260
84 3
Anchor bolts
m
13S8
54 23
67 79
0
0
0
0
544
Maia concrete
cu.m
1806
7231
90 39
500
9 039
35 156
45,195
8 45
Structural concrete
cu m
25 99
103 95
129 94
0
0
0
0
6 46
Formwort
sq.m
10 17
40 66
50 85
2,000
20 340
61 360
101,700
647
Steel reinforcement
T
248 56
994 32
1.242 90
50
12429
49718
62 145
8 48
Unmeaeured Ham*
*
1000
10.00
10 00
4.400I               17 599                 21 999
Subtotal
48,397
193.589               241.987BARO-AKOBO PROJECT In'agralad Matter Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Max. Rat. Level: EL 1,«10                    Dam Type: RocfcfW
TAMS ConsuMants. Inc.
01-Dec-8€
Inrt. Capacity: 112MW. 1I.4MW A 21MW Coal Level:                                                                                            Jan-9«
Unit Price!
Amount
Item
No.
DESCRIPTION
Units
Local
USS
Foreign
USS
Total
USS
Quantifies
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
6.6           Powerhouse (surface!
6.5.1
Coen moo excavation
cu.m
0.72
290
3 62
5.760
4 170
16681
20 851
652
Rock excavation
cum
1.81
7.23
904
3 850
6.961
27.843
34 804
653
Earth fil
cu m
045
181
226
3.240
1464
5.858
7 322
654
Mass concrete
cu m
1806
7231
90 39
836
15.113
60.453
75.566
655
Structural concrete
cu.m
25 99
103 95
129 94
785
20,401
81,602
102,003
656
Formwork
sq m
1017
40 68
50 85
2.406
24 469
97.876
122,345
65 7
Sleel reinforcement
T
248 58
994 32
1.242 90
160
39.773
159.091
198 864
6 58
Roofing
sqm
180.79
72314
90393
136
24,587
96.348
122,934
6.59
Stockwork
sq m
904
36 16
45 20
300
2.712
10,848
13.560
6.5.10
Miscellaneous Melahwxk
T
723 14
2.892 57
3,615.71
25
18 079
72.314
90.393
6.5.11
Slope Protection
sqm
452
10 08
2260
0
0
0
0
6512
Unmeasured Hems
%
10,00
10.00
10.00
15,773
63.091
76,864
Subtotal
173.501
694.006
867,507
66          Tailrace Channel
66 1
Common excavation
cum
0.72
290
362
0
0
0
0
662
Rxk excavation
cu.m
1 81
723
904
0
0
0
0
663
Unmeasured Hems
%
500
500
5 00
0
0
0
Subtotal                                                                                                                                                        0                           0                           0
6.7         Switchyard
.67.1         Common excavation
cu m
072
2 90
16 7.2      I Rock excavation
362
6 750
4 867 1                     19 548 I                    24 435 /
cu m
1 81
7 23
9 04
167 3       \F oundeltone end duct*
0
sq m
0
1                                 0I
12429
497 16
821 45
180
22 372 I              09 489 I
°1
16 7 4      \ Surfacing
111861 I
xq.m
1.47
5.87
7 34
\6 7 5         \Urwv*Mured Ham*
4,500
6 606 /                26 424 /
3JO3O 1
U
1OOO
10 00
10 OO
Sutrtcrtal
3 367 /   —
f 40.007BAR O-AKOBO PROJECT
JMaatar PUn
1            CnruuHMMa. Vmc .
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Max. Ree Laval: El.  MIS
Insl. Capacity:
Dem Type: Rockdll
12.2MW. 16.4MW&21MW
CoM Laval:           Jan 46
1------------1------------------------------------------------------------------
pern
|no.       DESCRIPTION
UnM Price*
Amount
1
Untie
Local
US 9
Foreign
US 9
Total
USS
Local
Quanlktlex | USS
Foreign
US I
Total I
US 1
7.0
7.1
A: CIVIL WORKS
DIVERSION WATERWAYS No J
PrrtltrJnMtei
711
MobllUMifln
L5
15 00
1500
15.00
222,634
690 536
1 113 170
712
Land acquislltan
ha
2 259 62
000
2 259.92
0
Q
0
0
7 13
Sila clearance
ha
1,694 67
6,779 46
8,474.33
0
0
0
0
Subtotal
222.634
990,636             1,113,170
7.2           Acceaa Roedt
7.2.1
i^oad Improwmanl
km
7.909 37
31,637 45
39,546 95
0
0
0
0
7 22
New Road
km
17,400 61
69.602 46
67.003.07
0
0
0
0
7 2.3
51/eam Crossk*fl
Mo.
22.699 20
90,392 50
112,991 00
0
0
0
0
Subtotal
q
q
Diver a I on Intake
7.3 1
Earth wvfHton
cu m
0 72
290
3,62
923
669
1,470
2 673
3,341
732
733
Rock ncwifai
co m
1 SI
7 23
S 04
513
7 350
Mast concrete
,cu m
1606
72 31
90 30
1 526
29 39ft
5.560
117,579
146 B74
7 3.4
Slmcldral condtii
cu.m
25 00
10395
4o.oa
994,32
129 94
430
11.595
4*3 776
50 47 J
7.3.5 7.3.6
737
Formwork
•-■I in
1017
50 55
1 546
16,774
14,666
75,095
58.665
93BS9
Steal remlorcamenl
T___
246 56
1 242 9Q
73 331
Unmaeaured Meme
U
500
5 00
sen
3 033
IS 334
Subtotal
ao.501
322,004
19,167 402,505BAROAKOBO PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
TAMS CoosuManta, Inc.
01-Dec-M
Mai. Res. Level: El   1,111
Dam Type:
Rock Oil
Inst. Capacity
12.2 MW. 18/4 MW A 21 MW
Cost Level:          Jan-86
Unit Prices
Amount
Mam
No.
DESCRIPTION
UnMs
Local
USS
Foreign
USS
Total
USS
Local
Quantities USS
Foreign
USS
Total
uss
A: CIVIL WORKS
7.4
Diversion Canal
74 1
Common excavation
cu.m
0 72
2.90
3.62
42 000
30 408
121.632
152.040
7 42
Rock excavation
cum
1.81
723
904
387 000
699,696
2.798,784
3.498,480
743
Earth M from borrow
cum
1 36
542
678
0
0
0
0
7.4 4
Hauling fill material
cuntfkm
0 10
0.41
051
0
0
0
0
745
Earth fUI
cum
045
1 81
226
0
0
0
0
746
Lining concrete
cu m
24 86
99 43
124 29
11 610
288.601
1.154 406
1.443 007
747
Structural concrete
cu.m
25 99
103 95
129 94
0
0
0
0
7.4.8
Formwork
sqm
10 17
40 68
50 85
0
0
0
0
749
Sleel remlorcemenl
T
248 58
994 32
1 242 90
427
106,144
424 575
530,718
7.4.10
Unmeasured items
%
500
500
5 00 |
56.242
224.970
281 212
Subtotal
1,181.091             4.724.366              5,905,457aMOvUCOW                   PWOJfCT
toiopfitod Muto Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
M*i. R«. L«vd: tl. 1.114
ln>IC»p«cl:y' 12JMW, 1MMWAB1MW
Dimlyp*:               Rockfm
1
CortL«v.L JinM
Unit Price ■
Armunt
|
rtem
No. (DESCRIPTION
UnMo
Local
US*
Foreign
US 1
ToUI
US*
Quantities
Local
US*
Foreign
US*
Total 1
US* |
B: ELECTRO-MECHANICAL EQUIPMENT
1.0 DAMS AND APPURTENANT WORKS
Lt
Power b apply Io the darn
LS.
10.000 00
40.000 00
50,000.00
1
10.000
40,000
50.000
1.2
intake and Bulkhead Gain - Low Lm< Outlet
each
000 00
3,200.00
4000 00
4
3,200
12 500
16.000
13
HHjh Pasture SJWe Galea - Low Laval Oiilto
each
9 500 00
39.200 00
49.00000
4
39 200
156 600
196.000
SubloUI
02,400
200,000
242.000
2.0
POWER PLANT No.1
2.1
Power Intake Galea
each
000 00
3 200.00
4 00000
2
1000
6.400                     6000
2.2
Pentlock
T
494 00
*.976 00
2 470 00
313
154,622
615,488                 773 110
|2 3
Into Veluea
each
22 000 00
55,000.00
110000 00
2
44 000
176.000               220000
24
TuiWnea Governor* and Turbine Amditoy Equipment
each
110 000 CO
484 00000
550 000 00
2
232 000
926.000
1.160 000
25
Generator* and Generator AuuAary Equipment
each
165.000 00
672 000 00
540 000 00
2
330.000
1 344 000
1 660.000
26
PcwYorhouse
15
45,000 00
1B0 OOO OO
275 000 00
1
45,000
iao.000
225.000
27
Station Aunktwry Mechanic** Equipment
15
60,000 00
276 000 00
345 000 00
1
69 OCC
276 000
345 000
2B
Stolon Auxttwy EltcUlcil Equipment
LS
151.000 00
724.000 00
005.000 00
1
101,000
724.000
905,000
2.9
Maki Tranatarmfire
each
3BD00D0
152 000 00
190 000 00
2
76,000
304 000
3BO.OOO
2 10
Switchyard Equipment
LS
110.000.00
440,000 00
550 000 00
1
110 000
440.000
550.000 1
2 11
UnmcABured Ham
.
%
10
10
to
124.922
429 669
624 611 |
"       “ 
"
Subtotal
1.374.144             8.4i«.a77              4,070,721
3.0             DIVERSION WATERWAYS No.1
[j J
I plwrilon !ntlk»
Iwcti | MO 00 |
3 100.00 I
4,000 .M~T
COO |
SDOO |
Subtotal
1.410                   1.0(H)BARO AKOBO PROJECT
Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBfLITY STUDY
COST ESTIMATE
TAMS Consultants, Inc.
01-Dec-84
Mai. Rea. Laval: El.  1,810
Inst. Capacity:
Unit Price#
Dam Type:
12.2MW, 18.4MM
RockfMI
/&21MW
Quantities
Coat Level:          Jan-88
litem
4.0
Units
Local
USS
Foreign
USS
Total
USS
Local
US S
Foreign
USS
Total
US S
41
B: ELECTRO-MECHANICAL EQUIPMENT
POWER PLANT No.2
Power inlake Gates
each
800 00
3200 00
4,000 00
2
1,600
6 400
8000
42
Penstock
T
494 00
1,976.00
2 470 00
341
168 454
673816
842 270
43
Inlet Valves
each
26.000 00
104.000 00
130 000 00
2
52000
208 000
260 000
4.4
Turbines. Governors and Turbine Auxiliary Equipment
each
147,000 00
586 000 00
735,000 00
2
294 000
1 176 000
1.470 000
4.5
Generators and Generator Auxiliary Equipment
each
254,000 00
1,016.000.00
1 270.000 00
2
508 000
2,032,000
2.540 000
4.8
Powerhouse Crane
LS
45 000 00
180 000 00
225.000 00
1
45 000
180.000
225 000
47
Station Auukary Mechanical Equipment
LS
73 000 00
292 000 00
365 000 00
1
73.000
292 000
365 000
48
Station Auxiliary Electrical Equipment
L.S
261,000 00
1 044 000 00
1.305.000 00
1
261 000
1.044,000
1 305 000
4.9
Maki Transformers
each
56 000 00
224 000 00
280 000 00
4 10
2
112000
448 000
560.000
Switchyard Equrpmenl
411
L.S.
120.000 00
480 000 00
600 000 00
1
120 000
Unmeasured Items
480 000
600 000
%
10
10
10
163 505
654 022
817 527
Subtotal
1.798,959              7,194.238               8.982,797
SO
[sj
DIVERSION WATERWAYS No,2_________
|Orverslon Intake Gates
4.000 00
Subtotal
2 1.600
1,800
6.400
8.400
8 000 |
8.000Wan
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY study
COST ESTIMATE
M1t
Dam Typo.
Rockflll
ln«t. Capacity; 12.2MW, H.4MVM < MW
Unit Prices
Cott Lav«l.
Amount
Foreign
B: ELECTRO-MECHANICAL EQUIPMENT
US I
6.0                POWER PLANT No.3
6.1
Power Intake Gates
each
000 00
3,200 00
4.000 00
2
1 600
6.2
Penstock
6 400
T
6 000
494 00
1,976 00
2 470 00
352
173 686
63
695 552
869 440
inlet Valves
each
26,000 00
112000 00
140 000 00
2
56 OOO
224 000
260 000
6.4
Turbines. Governors and Turbine A unitary Equipment
each
167 000 00
666 000 00
635 000 00
2
334 000
1,336,000
1 670 000
6.5
Generators end Generator Auxiliary Equipment
each
276 000 00
1 104,000 00
1 360,000 00
2
552 000
2 206 000
2 760 OOO
6.6
Powerhouse Crane
L.S
45 000 00
160 000.00
225 OOO OO
1
45 000
180 000
225.000
6.7
Station Auxiliary Mechanics! Equipment
L.S
75 000 00
300 OOOOO
375 000 00
1
75 000
300 000
375,000
66
Statirri AuxMiarv Electrical Equipment
LS
300 OOOOO
1 200 000 OO
1.500 OOO OO
1
300 000
1,200.000
1 500.000
69
M**" Tr ansiormer s
----------------------------
each
64,000 00
256.000 00
320,000 00
2
126,000
512 000
640 OOO
LS
125,000 00
500 OOOOO
625 OOO OO
1
125 000
500.000
0/5 OOO
6.11
U
10
IO
10
179 049 1.S44.437
716 195
7^74.147
695 244
S.447.4S4
8.0
transmission lines
------------- ..«*>»    Lin.    132-kV    from    oum.ro    No    1    to    C.mb.U-Qg, : Triwnl—Ion Lin. 13?-™ OlJ,n,,° N° 2 *
Tr.n.rr^oC ■ Ln. 132-kV f.<xn Ounw.o No 3 Io Oummo No2_
km
km
21 060 OO [
21060 00 I
64 240 00
64 240 txT
21 060 00 I                 M24QOO
105 300 00
105 300 00
105 300 00
14
9
19
294,640 I 99 540 400  «40
•■4.B24
1179, VO T 758  160  T
1600   500   I JIJl.OW
1 474,200
947 700
2 000 700
4.427.404■
>DRAWINGS
FOR
GUMERO HYDROELECTRIC PROJECTLIST OF DRAWINGS
Drawing
Title
GU-l
GU-2 
GU-3
GU-4
GU-5 
GU-6 
GU-7 
GU-8 
GU-9
GU-10
GU-l 1
Project Plan
Project Profile
Reservoir Plan
Gumero Dam - Plan
Gumero Dam - Profiles
Gumero Dam - Cross-Section and Power Outlet Gumero Dam - Spillway Profile and Sections
Power Diversions - Plans
Power Diversions - Intakes
Power Diversions - Canal Section and Penstocks Powerhouse No 1 - Plan and SectionPowerhouse No <
■ — ~ • >;
.
’-
C
Power Canal
Penstock —* 
it r«
.-
-  “  ,  -  Diversion  Dam and Intake No. 3
Diversion Dam and Intake No. 2
PROJECT LOCATION MAP
0       200     400km I—I----- 1--- ----- l
SCALE
MINISTRY OF WATER RESOURCES
A DO IS ABABA ETHIOPIA
TAMS - ULG
NEW YORK - LONDON - AQOtS ABABA
BAR0-AK0B0 MASTER PLAN PREFEASIBIUTY STUDIES
GUMERO HYDROELECTRIC POWER PROJECT
PROJECT PLAN
Date: October ’,996
I Dwg No GU — 1ELEVATION IN METERS
Gumero Reservq-
Normal Min. Leve, El 'goo Siormol Max. Leve) £ i. 1610
r'"'®'2    DQrl C 'ss: i. |S:5
Junaton witr Ofc River
Headwo'ks o* Dive-sior 1
7" EL 1465
Power Oonoi 0-!3m^»
— Penstock 2.0e
-Diversion 1 =lowerncjse
€.- 1340
|
_ «es<5worki g‘ Qiwi on 2 El. *305
- Power Cc'-oi O-:3nJ/i
1 ______________________________ '------ 1
1
1
V
1
1
1
1
1
--
\
1
1\ 4J
i
i
i
- Der a'.ack 2 0c 
~1
iI
iI
1
I!
I J
1
1
1
11
1
1
1
D vers or 2 Powe'house
r~r n2c
|
Headworks of Divers.or 3
/T EL 1010
I
'
Power Ccnal Q=’3rrT's
I
Penstoe* 2 0*
Diversion 3 Powerhouse 0. BOO
*NCE ?N KILOMETERS
MINISTRY OF WATER RESOURCES
ACDiS ABABA ETHIOPIA
TAMS - ULG
NEW *CRK - LONDON - ACDiS A9A3A
BARO-AKOBO MASTER PLAN PREFEASIBIUTY STUDIES
GUMERO HYDROELECTRIC POWER PROJECT PROJECT PROFILE
□etc: October 1996MINISTRY OF WATER RESOURCES
HAM
AOO<S ABABA ETHIOPIA
TAMS - ULG
NEW YORK - LONDON - ADO'S ABABA
•tx?
2 3km
BARO-AKOBO MASTER PLAN PREFEAS1BIUTY STUDIES
guwero hydroelectric power project RESERVOIR PLAN
Dote:ministry of water resources
__ __________ adoh aia rrmoiA__________________________
TAMS - ULG
__________________ Wgv TOOK - LOMDO - AflOH UUl_______________________________
BARO-AKOQO  master   plan   prefeasibility   studies gumero hydroelectric power project
GUMERO DAM - PLAN-PROFILE ON DIVERSION AND OUTLET TUNNEL
MINISTRY OF WATER RESOURCES
____________________ *00 H A 1*1 A                       _______________________ TAMS - ULG
______________ took - lomow • aoois *<*>*
BARO-AKOBO    MASTER    PLAN    PREFEASIBILITY    STUDIES “ GUKERO HYOROELECTRIC POWER PROJECT
GUMERO OAM - PROFILES
D«t« ; OcteMf rm
I              H SJ ■ 5I Dam
MINISTRY OF WATER RESOURCES
__________ ADO IS ABABA ETHIOPIA___________
TAMS - ULG
<¥ Yoax . LOMOOW - AOOIS ABABA
Ibaro-akobo master plan prefeasibility studies
GUMERO HYDROELECTRIC POWER PROJECT QAM CROSS - SECTION ANO POWER OUTLET
I
6U . 6Da® Crest EL 1615
Spillway Crtst El
/
Grout Curtain
0.075 Drain Holes Q5.0
075 Drain holes a 10.0 <!/gl
SECTION THROUGH SPILLWAY CREST STRUCTURE
v"
SECTION a
EU 15125
ST ILLI NG BASIN SECTION
El. 15725
\ .7
vi I VV’
*\ 1 \
\ -------- ------ -
NOTE : Drains and Anchors Same as on Chute
J\
T“ <
MINISTRY OF WATER RESOURCES
ado is abada mooriA
TAMS - ULG
MSV YOW . LONDON . ADO IS ABABA
barc-akobo master plan prefeasibility studies
GUNERO HYOROELECTRIC POWER PROJECT SPILLWAY PROFILE ANO SECTIONS
SECTION B-Bri
Paver house
El. 800
aenstock
Powtr Ctr.tl
I vers ion Di^
and mteke
El. WO
(Diversion 3)
Scale i
MINISTRY OF WATER RESOURCES AOOlS ABABA ETHIOPIA
TAMS - ULG
MEV TOftK - lOMQON - ADO'S ABABA
3-ARQ.AKQBO, MASTER plan prefeasibility studies GUMERO HYDROELECTRIC POWER PROJECT
POWER DIVERSIONS - PLANS
Scale 1 • 50,000
Date •- Octab«e
' Ovg He GU - 6ELEVATION
UPSTREAM ELEVATION OF SPILLWAY AND INTAKE.STRUCTURE
Scale 1:1000
Concrete Ogee Spillway
REFLECTED SECTION
Scale 1:200
PLAN
MINISTRY OF WATER RESOURCES
________________ ADO 15 ABABA fTMIOFU__________________
TAMS - ULG
______________WW YORK - LOWBOM . AQQ1S ABABA_________ BARg.AKOBO MASTER plan PREFEASI3IIITY STUDIES
GUMERO HYDROELECTRIC POWER PROJECT POWER DIVERSIONS - INTAKES
Ott« • October ****|
0*3 **•      6*J - 9Exlsfinq Ground
GUMERO 3 PENSTOCK AND POWERHOUSE PROFILE
|_--------- 7J>               ■           Can* liwrt POWER CANAL
TYPICAL SECTION ON STEEPLY SLOPING GROUND
Existing Grtxnd
Sirtacg
GUMERO 2 PENSTOCK AND POWERHOUSE PROFILE,
POWER CANAL
TYPICAL SECTION ON GENTLY SLOPING GROUND
GUMERO 1 PENSTOCK AND POWERHOUSE PROFILE
MINISTRY OF WATER RESOURCES
AOOIS ABABA ETHIOPIA
TAMS - ULG
_______ rout - lOXWM - ADO is ABABA
lARQ-AKOBO MASTER PLAN PREFEASIBILITY STUDIES GUMERO HYDROELECTRIC POWER PROJECT
POWER DIVERSIONS - CANAL SECTION ANO PENSTOCKS
; OcIeBtf ™ 
| CM — 5U • IOTYPICAL LAYOUT
NOTE:
*. Each of the three Power Plante contain two unite.
Powerhouse No 1:           2-6.1 uw Powerhouse No 2z 2x9 2MW Powerhouse No 3. 2xlO.5MW
• "
MINISTRY OF WATER RESOURCES ADOS ABABA CTVKJRA
TAMS - ULG
____________ NTS YCRX - LODO - ADOS ABABA___________________________
BAR0-AKQ80 MASTER PLAN PREFEAS BUTY STUDIES
GLBCRO HYDROELECTRIC POWER PROJECT TYPICAL POWERHOUSE - PLAN AHO SECTOR
Dote October 1996
[ 0*9 Nc CU - IIAPPENDIX 4-1
ITANG DAM
Detailed Cost EstimatesBAROAK OBO PROJECT
Integrated Matter Plan
ITANG IRRIGATION PROJECT
PREFEASIBILITY STUDY
DAM COST ESTIMATE
Max. Ret. Level: EL 431.6 Dam Type:                           Earthtai
DESCRIPTION
A: CIVIL WORKS
DAMS AND APPURTENANT WORKS
1.1      F Teliminaries
1.2      X kccess Roads
1.3     C diversion Canal
1.4     C Cofferdam
1.5        Embankment Dam
1.6        Spillway
1.7        I negation Intake
Local
Amount
1.703.059
7.909
250.866
72.680
8.003.262
1.126.418
189.534
11,353,729
6.812237
31.637
1.003.484
290 720
32.013 047
4.505 873
758.138
’•515257 29,5*7 1.25*%
363 Kfi «0.016 Xs
t e-v-i
<632 Cfr *47.872
TOTAL 1.0
B: ELECTRO-MECHANICAL EQUIPMENT
1.0         DAMS ANO APPURTENANT WORKS
1.1         Spillway Gates
11.2        Irrigation Intake Gates
45,414.916
406.000
24.000
430,000
1.624,000 96.000
2.030 OOC 12O0QG
TOTAL 1.0
1,720,000
2,150.000
TOTAL BASIC COST 11,783,729
Physical Contingencies 20°/<> 2,356,746
Engineering and Administration
TOTAL CONSTRUCTION COST
10°X. 1,414,047
| 15,554,522
47,134,916 9.426,913 5,656,190
62,218,085
51.31 IMS ii.7u.ra
7.070437 77,77UI1IT A NG IRRIGATION PROJECT
PREFEASIBILITY STUDY
DAM COST ESTIMATE
Mai. Rae. Level: CL  431.1
Dam Typo:       Earth Art
Coat Level:           JanAt
I—       ~1
lltam
[DESCRIPTION
Una Pfkee
Amount
UnMi
Local
US 1
Foreign
US 1
Total
USI
Local
Quan IM lot USS
Foreign
USI
Total
USS |
A: CIVIL WORKS
1.0 DAMS AND APPURTENANT WORKS
1.1             PreUmlnariea
1.1 1
MobtfizilKX)
%
1500
1500
1500
1,703 059
6 812.237
6515297
1.12
Land acquMion
ha
2.259 52
000
2 259 82
0
0
0
0
1.1.3
Site clearance
ha
1.694 57
5 770 46
5,474 33
0
0
0
0
Subtotal
1.703.059              6.512.237              6,515.297
1.2           Access Roads
1 21
Road Vnpro^emerM
km
7 90937
31 637 45
39 546 85
1
7909
31 637
39 547
122
New Road
km
17 40051
89 602 46
57 003 07
0
0
0
0
123
Sbeam Ctoeeing
No
22 596 20
90 392 60
112 991 00
0
0
0
0
Subtotal
7.909
31.637
39.547
13            DiworUon Canal
111
Common E icaveHon
cum
072
2-90
3 62
330 000
236 920
955 600
1 194 600 1
1.3.2
Rock E »ca*aLon
cu m
1 51
723
904
0
0
0
01
1 33
Earth Fiu
Cu m
045
I 61
2 25
0
0
0
01
134
LbtUng Concrete
cum
26 25
11295
141 24
0
0
0
01
1 35
Slrudutal ecocide
cu m
25 99
IO3V5
129 94
0
0
6
|l 3 0
FofrrvMCrfb
eq m
10 17
40 60
50 66
0
0
0
01
01
h37
Sled leeWorcamanl
T
24e $a
904 32
1 242 90
0
0
0
01
|t 36
Urvneaeoed lame
U
500
500
6 00
11 vae
47 764
W 7 JO I
BuUulalBAROAKOBO PROJECT Integrated Master Plan
ITANG IRRIGATION PROJECT
PREFEASIBILITY STUDY
DAM COST ESTIMATE
TAMS Con sunants, Inc, 07-Nov-M
Max. Res. Level: El. 431.1
Dam Type: Earthflll
Cost Level:             Jan-44
Unit Prket
Amount
Item
No.
DESCRIPTION
Units
Local
USS
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
1.4 Coffer dim
141 Foundation excavation ■ Common
cum
0.72
290
3.62
10,000
7,240
28.960
36 200
1.4.2
Foundation excavation • Rock
cu.m
1.81
7.23
904
0
0
0
0
1.43
Borrow excavalion - Earth
cu m
068
2.71
339
48,700
33.019
132,074
165 093
1.4.4
Borrow excavation - Rock
cu.m
096
384
4.80
3 000
2 880
11.520
14 400
145
Hauling M material (over 2 km)
cu m/km
010
041
0 51
0
0
0
0
1.4.6
Unprocessed TiN (placement)
cu.m
045
181
226
48.700
22012
88 050
110 062
1.4.7
Processed fill (placement)
cu m
1.36
5.42
6.78
3.000
4 068
16 272
20 340
1.4.8
Unmeasured items
%
500
500
500
3 461
13 844
17.305
Subtotal
72.680
290.720
363.400
1.5 Embankment Dam
15.1
Foundation excavation - Common
cu.m
0.72
290
362
437.000
316.388
1,265.552
1.581 940
1.5 2
Foundation excavation - Rock
cu m
181
7.23
904
0
0
0
0
1.5.3
Borrow excavation - Earth
cu.m
068
2.71
339
1 316.000
892248
3 568 992
4 461.240
1.5.4
Borrow excavation - Rock
cu m
096
384
480
159 000
152.640
610560
763 200
1.55
Hauling fik material (over 2 km)
cu rrVkm
010
041
0.51
0
0
0
0
1.5.6
Impervious core
cu.m
226
904
11 30
1 581.500               3 574 190
14296 760
17 870 950
157
Unprocessed Ml (placemen!)
cu m
045
1 81
226
1 316000 i              594.832
2 379 328
2974 160
It 58
Processed Ml (placement)
cu m
1 36
542
678
0I
0
0
It 59
Fttms
cu m
339
1356
1695
It 5 to
Drains transitions
°1
66 000 1 223 740 1 894 960
1 118 700
cu m
339
1356
It 5.1 i 1 Rip tap (placement)
1695
461 000 1        1 630 590 /           8 522 360
,
cu m
8 152 950 /
,
113
4 52
565
m
T
%
210200 1               237 526 I          950 104 /          f                  /
11 30
11299
500
45 20
451 97
500
56 50 1
5Q4 90 1
------------- 5,00 1
0 1               01                of                 o 1 ---------------- 0 J                        01                 ol                 0 /
----------- 1        Jaifoa /               1.5^4 ot /               i.oojflLw/
0,001.2021TANG IRRIGATION PROjeCT
PREFEASIBILITY STUDY
DAM COST ESTIMATE
Mm. H«a. Laval: EL 4*1.*
CwnTypa: CaithlMI
11
/not I
UnM Pricot
Coil Laval . Jan-H
Amount
|
[No.           [DESCRIPTION
Unit
Local
U$l
Foreign
US!
Toil.)
US 1
Quinliltat
Local       I US!
Foreign 1
US!
Total i
US 1 1
A: CIVIL WORKS
1.1 SpMiwjy
1 fl 1
Bulk                       • Common
cu.m
0.72
2 BO
3 62
18 000
13 032
52.120
85 180
1.6 J
Bulk mmhUob - Rock
cu m
1 Bl
7 23
904
IB 000
32 544
130,178
192 720
1.6.3
Structural eKcavaliofi - Rock
CU m
4 52
1008
22 60
0
0
0
0
1,0.4
Mm concede
cum
1008
72 31
90 36
37.213
672.737
2 600 5^8
J 363 683
165
Structural conciolo
cum
25W
103 95
129 94
5 650
152 030
808 119
780.149
166
F(NTTM<Nk
aqm
10.17
40 68
50 85
S.490
55 633
223,333
279 167
1 67
SUd icinlorMnwnt
T
246 56
004 32
1,242 90
486
llfl 335
465*42
581 077
166
OiMung lor (Natna
m
11 30
45 20
Sfl 50
210
2 373
9.492
11 665
1.!!
Drilling lor groulmg and ckuniiliom QaN )
m
1562
63 77
7909
250
3.954
15 818
19 773
1 6 10
Anchoit (trxJ, dulling       grouting)
T
2.962 96
11 931 as
14 914 Bl
67
19966
79,94*
9W &2u
4 6 11
Qraudna
T
11299
451 97
564 96
35
3,965
TS 619
ID 774 |
1 5 12
UrwnuBuivd rtMTiA
%
500
5 00
SCO
53 639
214SM
266 196
Subtotal
1.126.414               <505673            5,832.091
1.7           kf*q«lk)n Intake
CortWTtcm Eva laiion
Cm m
0 72
2.90
362
1 000
V71
11 77
774
7 696
3«J 1
Rock F.«ca*alwn
tum
1 61
7 23
9D4
0
O
O
O
|1 73
EaiinFA
C
U lYk
045
1 61
226
0
O
Q
0
,7a
I75
1 78
17 7
tTA
[Lirunfl ccnc-iri®
cu m
40 66
162 70
203 38
0
□
O
0
&inxdui*l cwwaU
cu m
»W
103 95
129 94
2025
52 5.*O
210 503
JflJ.IJU
FwmAcrt
m
10 17
0 60
50 65
« 075
61 763
247 131
xw.aia
aiM* i »kdu c«m*nt
T
?u &a
W*4 32
1
283
65 J?7
281
k* tai
li itwMMuad lama
%
500
500
Bod
9 026
« 102
as 137
1
Subtotal
laO.SM
♦4/8/2
SLAPPENDIX 4-2 ITANG IRRIGATION PROJECT
Economic AnalysiskTable I: Economic Return by Cropt
COW’*’
h>c
'FT?            'Hr!            'W»
• W
t Sea
2 J»
;son
4  512
•3*2
• S’2
•1*2
4 jse
•3*2
5M
•n
>34
1*2K
4 415
4415
4 IM
• 5*0
iva>
• ST
r
1JU
<F4
in
Soy* 8**”
r               W)
wJ
2)05
4 ns
4 000
TM
TM
7W
1 M9
4.73
7M
• 721
no
MS
2JW
•is
1074
ICT
v*r J
IWC
:M’
:s 4'
l«r
• • >sxoc I«r 25473Table 2: Cropping Build-up (ha)Table 2: Cropping Buildup (IM>
»IO
MO
J»n
MO
MO         MO
MO
Md
MO
MO
too
MO
MO
MO
MO
MO
MO
JOI*
MO
MO
MB
MO
MO
MO
MO
MO
Mu
JO J J
MJ
Me
MJ
MU
MJ
W
MG
MO
2014
MO
JW
MO
MO
MO
MU
MQ
MO
MO
«
ts
JOT? w                ljyj|
Nil
MO
MU
20r»
MO
AM
MO             *
MO > M3
1W
MJ
icr»
5W
MO
JOr*
MO
MO
_
MC              MO              MO             5B0                *
___              MO
MO              MO              MO
M20
MO
MO
MO
MO
MO
SM
MO
MO             MO
MB
■-
44a MO
’ *■
MO
[-
-
MO MO
MO MO
MO MO
MQ !*J
MO
MO
MO
------------ •
MO
ato
MO
MO
aw
4 Ad MO
!40 MO
'---------- *
—
-
-
3K             MO
MO
*■" 1
J
MO 5« M0 MO MO MO MO MO MO &IIO 980 MU MG MO MO MO MO MO
MO               3*J              4W               MO   1          MO
MO              MO
3«0              MO            MJ
AJO             UJ
• MC             r,»a                 U»
• Ml             1. *»
ron
MC
MO
3M
MO
MO
MO
MO
MO
MO
- -- —
MJ
T“2
MO
MO
MO
MO
MG
a2>
• ill
JGH1
MOI
■jMI
VK1
MO
4KJ
MO
MO
a .4U
5BU
MQ
MO
MO
MU
4Ji
4U1
•
*
■II
1 'M
,J
?CI5
jo r 4
H14       JOO/
400
■X
400
•UD --------        ME
•w
400
400
4U>
.\W roa ®w
•»          •90           MO
MB «n -M
-
4441 i zn IJOO *JM
rt’J         WU            JSJ4
*w             4W           ■CO
«n                MO              *X0
*»
400
•to
t- "            £»
400             •DO            400               «                 ««              400              •N                401
1
•jo                «JD
«XJ           1OD             •XJ             *J0
•>/                ■X/               •X)             -CO
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■QU
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4®
•JU
•W               •X
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44Q             400             «J0              •XI
*uu               «»
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.
i —  ”-------
•W
•XJ
KJD
•JO
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400
■JJ
<A>
•X
«£
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•30 *J1
«0 ■Ol
*»
«
40
4U0
•XI              4O>               VJ                                MJLI           409              AM             kii 430              400             •JO              •JO            •MJ              4ix>             4OU
-»                 •jQ             400             •JU            44 JU            •JU               4UU             kN
• JU                •xi
•w             400              400              *Jk>               MAJ            4449
---- FT—
■■
«Xl
1 .   —4
-
-
—
-
4® *w
MU
—
O? 400 403 •30 400 | •ai
4LU •JU 40) 4C0 •JO 4dU
•M
MA|
4LU              •N               •JU              •Jj               «J0                                  aM 1             •UU «>               •JQ              •u              «N               402 L                   *»               •M                •N
■
40/
•XJ              •xj
•XI
**J F             MN              • V
r—------ . .
— -
«do                                                     mJ        4UU
•»
kN
1                           1           401              •XJ              •jJ *             *V              •N
■JI
4J4              '24
Ml
v.m        IBM           LM
liM           IBM          > W>
4*
4B*|               Utt              LW4 1       i,«m i        4.U4             1 *»             IUI              4 U»*
- jj
1
II Lh
1
LLLL
88§
1         ii3 8 8 i
i        Hi'
88888
88i
8 8 =1
k        i
1•
i
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5
p
io o o S S 8 111
XI
OoOOQ
s s s ?|
i
i1ii
I'
8888888
g       I ' 1
s   111
SO8iS
1u
s s cl
;1
It
t’ 1 ‘
■1
II'
t1
I
ill1
ii i
I 1 1 1        8 8   8 8 8 8 8 8          8l8            pi
rnrli
>55
8ooooooo
C ||
Table 2: Cropping Build-up (ha)ii
1 1 • I S
•1            1 1 '
IB
i1
i
■I
-I
Ii
11
1J.
1
’ i ■ n I ibi
i
1    ! B'iKi
i
1 S g g
i                               BBSS
i                            BEKSg
f g 0 filg g E
*• li   ;     i
i i-J- S g SiS U 0
__
1 ft        H , j i 1 '     1
s gggggglgg
i               BE B B S B g 0 g
'i     'i
;
1             g gg 5 K g e g SB
p*              i.i.     : ....
I                 BBS'S US BEU I       mils g gg g g gig g g
i ;BIkIb      gggfigggfiSg
*        IT              1 1       i
1
I                       mmUSm&S
A
I UHS BRSTBSE'ilO
£■              I 4 "fl 1
U: r *- SEggggSgggggggg
to to      Sgggggggggggggg *
i «
to to fgggEgggggggggg
S’ 1
£E
*
£ e
to to |
IHmmUSH g
b
Table 2i Cropping Build-up (ha)Table 3: Benefit Build-up (Birr ,000)
2CW    2001    2002    2003         2004         200$            2000           200T            2006            2009            2010           2011            2012           201J
2014            2015           2016
20f7              Wil             JOffl         2020           2021           2022
----------
1--------- 1
(W»
71       L 1W2           3 61!              MW           5416          5,416           6.416           5416          5 418
1103)                a
’ 78
3811 5 416 5416 5416 5410 5418
1682 3611 5418 5 416 5.418 5416
.. .
—
(I03J                78                   >N2           3611            5418           5 416           5 416
(*03)                78                  1882           3611            5418           5.416
.     (103)               71           1862           3611            5416
(103)              78           1862           3811
(103)
78                 1682
- —1
(103) 78
(’03)
■
.. ..
■
- -- - *
5418          5 416          5.416
5,416           5 416          5.416
5418           5 416          5.418
5,416            5416           5411
MW          5 416           5418
6416           5 416           5416
5416          5 416           5418
3611            5418           5418
1682           3611            5418
78           1882           3811 (1WI              76           1 M2
(103)              78
(103)
•
•
<w»
(W
till
1,444         10,864        14.300         21,718        JT.132        32,648        37.864
43,346        44,786         64,212
1.416          5,416          5 414          5.4 <4 T       5414           1414
5 410           5 416           5 416           6.414 1        5 4t4 [        5416
5 416            1416)      5.4 mJ      5416 |         5416           54M 5.416          5.416          5 416           54M            6414           6414
5 416          5 416           5416           5414          5 414          5.414
MW          5.416          5.414           1414           5414           5414
5 416          5 416            5418            5414           5 414          5414
5416           5418           5418          5,416            MW            5414
5 416          5,414          5.416           5416           5 416             MW 5.416           5411           5416           54'8           5 414          5 414 3 811           5 418          5 416           5416           5 416           5414
1862           3811           5 416          5 416           1414             5<t4 71           1 M2           3611           5^16           5 416           5416
(1031               78          1                  3611           5,416           5414 (103)               78            1662           3611            1414
mi              63          2 081             5H5 it, ill        44 044         78,462         76.MI          11,464         47M4*--------------------------------------------------------
TM9 J: BenaHr BuiM-up (Birr ,OOO>Table 3: Benefit Build-up (Birr ,000)J: BenvfTc Build-up (Birr ,OOC>
— ffoa               ?W/ «C)                2«M           MKrt            KEJ*            MO.*
2Wf              Mifl
»ip              ztfri              WU             MM           3013              Mr*
JtfM
/or*
jsrv
j*CJO
202 r          jvjjI
OUkhrt
*OT     u»4 1
1JM
1 CLM
iMJ 1 Ml 1 *43 1 443 1.4*3 i m 1 441 1*43 1 *43 i.*O
1 OM IZ2S kMJ . 1*0 l.UJ
» U>              1 Ml             1.4*3
t *41
lm L
LU)
Z—
*»           1 B04
I2H
i **3            1.443
*» l 024 izn 1 443
1««            • 225
1 441             1 MJ             T 4*3
» 4*4              l.*43             1.4*3
1 Ml              1M3             » *43
1 Ml             1 MJ              1443
i.»           1MJ                1.4*3 I 0/4            1 274               I.UJ
■4           10/4                 1)34 «n             L£K*
1 U)
1 441
t 443
1 Ml
1 MJ
1 U)
1 Ml
1 •<)
1U3
1.225
l 024
»
1 Ml
1.443
1 44)
1.4*3
1 4*1
1.4*3
1 4*3
1.443
1.4*3
'««
1 rt)
Iflli
«»
1.443 1.443 1.443 1 M> 1.443 1 Ml 1.443 i 441 1 441 1 M) 1.443 1 443 1 44) ><« 1,443 1.441 L.443 1.441 1.441 1 Ml
1 443            1 «J
1 221               1 **l 1 024               1 W)
M*             1 02*
40*
M.U1
1 *43            1 4* ]               1 4*J            1 443
1 443            1 *43               1 *43            1 441 1.44)               1 Ml               1 UJ            1 U1 1 443              1 4*3               1 M3            1.441
i.M)             1 443              1 4*1            1 4*3
1 443               1 Ml
1 Ml            ■ 443
i
1 gZ4
K»
- 'I
-1
_p
_
—- ■
- . _.
.
«•-,
_
— -
. _____ .
— -
y -r-T—
1X1
1 441              1 4*1                1 U)            1 441
■ M3            1 443               1 44j            1 44) l 443               ’ MJ                l.*4j            1' *43 . 1 *41               1 *4)                1 Ml            1 443 1 4*3              1 4*J             1 44 1            • U1
_______
___ , -
—_
JM              1 *43            1 M>
--
-—
1 *4 J 1 4*4 1 M3 1.4*3
■ 34* • MJ 1 Ml L 443
■
—
Ml
—
i—                                                            —
__________
—1
—
■-
'
i*rt i u**
*ur              LM»
■ .----------
r.M]
WIFt
I---------------           —
—
—
IUW          11 IM          M.4M
1.024
M4
I 22*              1 4*3            1.M)
M-MI
■ r*M
11,1*4          IJ 414
1 L.toM
- -----------T?
XJ Ml           41, IM
/iMU
—«
Muir —£77       M.1
KIM
urn
p >rt.
MftM
U*M
KIM          a£kM          10 CM            K M4              KIM             MH4
—
W<*             nip             /tri*
wrf
•u«M
»*/M
i
put,
UM*               U«
MM*          W*M          U *M             » V*
.—
10 bM         WfcU            WtM              WW
WW
z _ .
UK* V IM
<»U*J        ! ~M)M
XI *14               KU*            W.W           10*44 3> Ffp                «**             U U*            H*QO              WW           W IM
. PIWJ                    M 33*            W IM              WlM
PW             k n*             10*5*
»*M
~ 71’~ I 1
—
■*> 4<M             bu u*
-------- ■
V3 434 W*M »M4 VjfcM W*M W«*4 UM* UM4 M M< 11*54 12M 1J*M W«4 WOM Xj »M bl*M 1 W|M W4M
W **4 J0*!M KiM* WM4 1 K4M KlBM
U«M               UlW          12 *M             UM               u*-ta            12
W*M              W«4        ■WJ4IM
kJ nil           4>J IM
_______
t _____ __ ftJM
■KMF.WK",l            WIM              MM*               MM*             Wl *14          9U *M
!■ —               -.----------
PMJf        >. J iHj
iJ IM             W IM           12 *M
1 . —.--------
U U4
M «M
IM FM
—
I. ....
. ---------------
(? 1 L*|
•
1*-
*            |»W
tf
IM. IM                                111 M            041/1           XU.UI             WliB
Will       13471*         1*4 >»
HJM          XI *44             H*M               MM4 '           H.4M
*U.M* 441 iM 44X«M 44X44* MX«M Mi M4Table 3: Benefit Build-up (Birr ,000)
Summary
poc
cwi     mo
?MOJ
XXM         2005
Conofl
."1
_(1W)
2M6(
BM
(70)
6.361
1.BS3
Bwm VtftMttea F«4iif
0«mW
M*______
‘-
346 WO
100
MO
70S
M 70S
27.395
20W
1657
11.400
OU
2 190
254
1551
1.551
71909
2007 5460 172M 6 910 3 741
356 2586
2 568 130749
roof
10664
73,175
9 101
5 2M
463
3MI
3361
154 165
2009             MIO
16 300
M062
21 718
34M9
11.609          14.04
2072 17  055 94  629 40154
24 676
1676
16 300
16 306
a*.'494
743,901
210.244
6 636
*
4 595
4 566
146646
220.210
0.364
5010
5.610
161 560
27M66
M11
27.132
40636
-*
9.631
776
6625
6.625
734 0 73
342.900
Mfl
32 546
46 724
19 101
11 479
680
7640
7640
292 913
410,924 i
MO
37 964
5261£j
58 496
M»5
46 796
64)65
Mf«
54J12
70272
21 599         24.097
26.595           MOM
13026
9M
9655
9 655
308.329
14 574 j        16122         17 669
tow
M»7
56429
78.180 31591
19217
1,401
M»»
7040
88 124
36 635
72 337
MM
75 985
91516
36 SM
23 556
<04
1615 1 645
•1456
0697
39 698
24 536
« AAS
9 669
---------- -—4
9 669
JOO 913 j
14.782 15.526 16042
14 782 15 526 18042
482.464
711,10
462 494 462 494
714.770 736.619
i—
451.621      461.706
1,193
10 IMM
10664
335 724
914.163
1M7
11699
11666
386 237
684,171
12.714 12.714
447  076 moor
Mfl
65 044
0 047
34 089
20 764
1.505
11726
13 729 462 494 693.400
30.193
102 l»      177 349Tibfe 4; Coses
Financial Coju ($ million)
w                 Jap.'          KOJ
XU<              M21             MX*
L,<p4flJ COlLl
Q5MCOM1
T<H*> 1 .
?W4                Wl             APIS            ?SI I
Ji M ♦3 41 «l 0®
0 13
51.19
40 M
0 13
40 47
ii n        JO 75          23*1
-—
HU U.»l|
6 if
n ii ’
140
1XU
’*
ttir ft ST
17 7J
W
1950
l*W         13 41
7M
17 Ji K41
293
19 40
Tn" 3 7/ I
1105 I
JO* 4         .V'D
4 11 1 '
4 19 4 25
----- ,         , —
?UA*
4 JJ
■0 OJ I 4 25           4.33
Economic Com (Birr million)
ilTable 5: Cost Benefit Analysis
Cost Benefit Stream(Birr million)
f---------
2000 2001 2002          2003          2004          2005         2000        200?        20001       2009 2OloJ 2011                      2OI2i 2013               2014        2015         2010        201?        2010        2019 WO I 2021 2022 39
ICoiti
iBonofltt
OOO' 194 821 319 m]         45091 303 55 l66 60 160 3 ft 100 76 145 79,140 52 130 01 j 123 1l| 145 53 194 331 190 63 13926 9042( 9212] 7524 31 M 32511 3251. 3251
r
|
0        00        oooT            ooo’
0 00 *194 82* 319 64*         •461.91 *306.97'*12931 -63.49’ 11.411 03.401 71.091142.60 [219.491273.39 > 267.50 f205.16 374931493.761548 39 610 16*879 34'09X201 703 321 71099
000 342 38 29 102 82* 177 35 210 24 220 21 272 60 342 6o‘418 92 451 82 481 79| 514 1l| 504 16I 660 50 693 40 - »1 18 724 77 735 83 743 50
r
IERR 13%
12DRAWINGS
FOR
ITANG IRRIGATION PROJECTDrawine
IT-1
IT-2
IT-3
IT-4
IT-5
IT-6
rr-7
IT-8
IT-9
rr-io rr-ii
IT-12
IT-13
IT-14
LIST OF DRAWINGS
Title
Project Plan
Irrigation Project Layout
Itang Dam - Plan
Itang Dam - Cross-Section
Itang Dam Profile and Spillway Section
Main Canal Conveyance - Length Profile
Flood Protection Dikes - Length Profile
Typical Canal Section on Slope
Typical Canal Section on Flat Terrain
Typical Flood Protection Dike Section
Typical Drainage Pumping Station at Flood Protection Dike Typical Irrigation Sector - Gravity System Layout
Typical Irrigation Sector - Sprinkler System Layout Typical On-Farm Gravity Irrigation System LayoutJ r Bam Akobo Basin L
End of Main Canal
PROJECT
LOCATION
/
e Ghimbi           Addls Ababa
f \BedeJe *
Itang Dam
. Hood Protection Dike No. 1
——
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Summery

Summary: Baro-Akobo River Basin Population Study

Summary of the Baro-Akobo River Basin Integrated Development Master Plan - Annex 3A: Population Aspects

Overview

This document is part of the Baro-Akobo River Basin Integrated Development Master Plan Study conducted by TAMS-ULG for the Ethiopian Ministry of Water Resources. Annex 3A focuses on socio-economic aspects, specifically population dynamics, including past trends, present conditions, and future projections for the Baro-Akobo River Basin in Ethiopia.

Key Sections

1. Introduction

Defines the demographic study's scope: evaluating present population, past evolution, and future projections.
Methodology: Uses the "components method" (natality, mortality, migration) for projections.
Data limitations: Relies on 1984 census data due to unavailability of 1994 census results during the study.

2. Institutional Aspects

Data sources: Central Statistical Authority (CSA), Ministry of Health, NGOs, UNHCR, National Urban Planning Institute (NUPI).
Ethiopia's National Population Policy (1993) aims to harmonize population growth with resource capacity, targeting reduced fertility and improved welfare.

3. Analysis

3.1 Population Characteristics

1993 Population: ~2.2 million in the project area (75,912 km²), with densities ranging from 7 persons/km² (Gambela) to 55 persons/km² (Oromiya).
Past Evolution (1984-1993): Significant population fluctuations due to refugees (Sudanese) and resettled people (from northern Ethiopia). Gambela's population doubled due to these events.
Age/Sex Structure: Young population (median age ~17), with high dependency ratios.

3.2 Urbanization

Urban Population (1993): 8.1% of total, concentrated in small towns (<20,000 people).
Future Urban Growth: Projected to reach 15% by 2035, with Gambela as the largest town (~151,000 people).

3.3 Fertility

High Fertility: Total Fertility Rate (TFR) ~7.5 in rural areas, ~6.4 in urban areas (1990).
Future Projections: TFR decline targeted to 4.0 by 2015 (policy goal), but slower decline assumed in projections.

3.4 Mortality

High Mortality: Life expectancy ~53 years (1990), with infant mortality ~105‰.
AIDS Impact: Rising HIV prevalence, projected to increase adult mortality significantly, especially in urban areas.

3.5 Migration

Past Migration: Large-scale resettlement (1985) and refugee influx (Sudanese) disrupted population patterns.
Future Trends: Rural-to-urban migration expected to intensify, with Gambela as a major destination.

4. Conclusions and Implications

Population Growth: Projected to increase from 2.2 million (1995) to 5.3 million (2035), with densities rising to ~70 persons/km².
Challenges: High population pressure on land, environmental degradation, and urban service demands.
Refugees: Continued presence could exacerbate local pressures, especially in Gambela.

5. Need for Further Studies

Updated census data (1994) required for accurate projections.
Detailed studies on land use, health, fertility determinants, and urban development strategies recommended.

        Key Data Tables
        
                Indicator
                1995
                2035 Projection
            
                Total Population
                2.2 million
                5.3 million
            
                Urban Population (%)
                8.3%
                14.7%
            
                Density (persons/km²)
                29.1
                69.5
            
                Total Fertility Rate (rural)
                7.5
                5.8
            
                Life Expectancy (years)
                53-56
                56-62