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FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA
MINISTRY OF WATER RESOURCES
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BARO-AKOBO RIVER BASIN
INTEGRATED DEVELOPMENT
MASTER PLAN STUDY
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FINAL RETORT
VOLUME V
PREFEASIBIL1TY STUDIES
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t. 'J. it.FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA MINISTRY OF WATER RESOURCES
BARO-AKOBO RIVER BASIN INTEGRATED DEVELOPMENT
MASTER PLAN STUDY
VOLUME V
PREFEASIBILITY STUDIES
TAMS-ULG Bart>-Akobo River Basin Initialed Devdnpment Master Planindex of volumes and annexes
Volume 1:EXECUTIVE SUMMARY
Volume IT:RESOURCE BASE AND DEVELOPMENT OPTION'S Volume ITI:-MASTER PLAN DEVELOPMENT
Volume IV:PROJECT AREA MAPS
Volume V............................................. PREFEA SIB ILtTY STUDIES ANNEXES
1.        ^A TER RESOURCES
Annex IA
Annex IB Hydrology Annex 1C Flood Studies Annex ID GroundWater
....... ...Climatology
Annex jeReservoir Operation Studies Annex IFSediment Studies
Annex 1GWater Resources Cost Estimating Annex 1HIrrigation Projects
Annex IIWater Supply Projects
Annex 1J 
2 AMH7A4E RESOURCES
Hydropower Projects
Annex 2A ............................................Land Evaluation
Annex 2B ...
Annex 2C
Annex 2D Mineral Resources Annex 2E.. Forestry
Soils and Soil Conservation
...........Geology
Annex 2F ............................................ Wildlife
.Annex 2G ..................................... Tourism
Annex 2H
Apiculture
Annex 21............................. ...... Agriculture
.Annex 2JRenewable Energy
Annex 2K
Fisheries
Annex 2L ............................................ Livestock
3. SOCIO-ECONOMICS
.Annex 3 A ..........................................Population Aspects
■Annex 3B ...
... SocioEthnic Groups Analysis
.Annex 3C Economic Infrastructures
.Annex 3D ... Social Infrastructures
Annex 3E
Economic and Financial Analysis
.Annex 3 F ........................................ Institutional Support
4- ENVIRONMENT
Annex 4 Environment
TAMS-LILG B«ro-Aliobo River Basin Iuteurated Development Master PlanPREFEASIBILITY STUDIES
VOLUME V
VOLUME V
PREFEASIBILITY STUDIES
TAMS-ULG Baro-Akobo River Basin Integrated Development Master PlanPREFEASIBILITY STUDIES
VOLUME V
CONTENTS
1.     BACKGROUND...................................................................................................................................
1 1 Master Plan Studies ............ ............................. ■■     .......................................
1.2        Selection of Candidate Projects               ........................................................
13 Study Limitations......................................................... .................. . .....................................
2.     GEBA HYDROELECTRIC PROJECT.................................................. .................. -.......... ....... ™
2.1        Introduction..................................
2.          J / Project Concept.. . .................. .......................... .................. ................. . .......... ........
2.12 Project Area..............................................................................................................................
2.L 3 Power Planning........................................................................................................................
2 2 Basic Data ................... ■■■■..................... .     ..    ....................................... -............................
2.2.1    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......................... ................................................................. .... 8
2.3.3    Access and Transmission Lines..... ........... .......................... ......................... ..... .............. 10
2.3.4    Project Layout.......... .............................. ................... ................... . ................................. 10
2.3.5    Project Selection and Optimisation....... . ............................... .... ...... .......................... ..... 11
2.4   Environmental Assessment ................................................................ ....................................... 14
2 5 The Recommended Project.................... .................................20
2.5.1    Project Description.......... . .............................................. ................ ................................... 20
2.5.2    Quantity and Cost Estimate........................................................... ....................... . ........... 21
2.5.3    Implementation Schedule................... ...... .................... . ................ ............................ ......23
2 6 Economic Appraisal.................................................. ...................... ................................... ..... ,23
3.     GUMERO HYDROELECTRIC PROJECT................. 3,1  Introduction............... .......................... ............
3.1.1    Project Concept..............................
3.1.2    Project Area...........................................
3.1.3    Power Planning. ...,........................
3 2 Basic Data
3.2.1    Topography .............. ........ ..........
3.2.2    Hydrology...............................................
3.2.3    Site Geology................... .......................
3 3 Project Development
3.3.1    Project Options.............................
3.3.2    Reservoir Operation Studies.................
3           3.3 Access and 1ransmission Lines.......
3.3.4    Project Layout..................
3.3.5    Project Selection and Optimisation 3 4 Environmental Assessment
3 5 The Recommended Project
3.5.1    Project Description.
3.5.2    Quantity and Cost Estimate. .........
................................ 25
25
25
25
25
26
.26
.26
.27
.28
.28
.28
.30
.31
.31
34
.40
.40 42
TaMS-1 LC BanxAktfbo River Butn Integrated Development Majier Pl»n
iPREFEASEBlLm STUDIES
volume v
Table 2.1
Table 2.2
Table 2.3
Table 2 4
Table 2.5
Table 2.6
Table 2.7
Table 2.8
Table 2 9
Table 2 10
Table 2 11
Table 3 1
Table 3 2
Table 3 3
Table 3 4
Table 3.5
TABLES
Average Monthly Flows at Geba Dam (m7s)........................................
Flood Frequency Analysis at Geba Dam.................................................
Probable Maximum Precipitation............................................................. Geba Reservoir Firm Flow (m3/s)............................................................. Monthly Flows at Geba Dam (mJ/s).........................................................
Geba Hydroelectric Project - Annual Firm Energy (GWh)....................... Project  Optimisation  Reservoir  and  Power  Plant  Characteristics Project Optimization - Cost Estimates (USS ,000)
Project Optimisation - Internal Rate of Return.........................................
Unit Prices (January 1996)................................................................. Geba Hydroelectric Project Cost Estimate (USS - January 1996) Average Monthly Flows at Gumero Dam (m3/s).....................................
Flood Frequency Analysis at Gumero Dam............................................
Probable Maximum Precipitation.............................................................
Monthly Flows at Gumero Dam (m’/s)..................................................... Gumero Reservoir Firm Flow' (m5/s)....................................................
--6
.............. 6
.......... .6
........... . 8
........ ...  .9
.......... ID
- 11
......... 13
......... 14
........... 22
......... .23
26
.............27
.............27
.............29
............ 30
Table 3 6      Gumero Hydroelectric 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 of Return.............................................................  34
Table 3 10 Unit Prices (January 1996) ................................. .......................................... . ......... .........42
Table 3 11   Gumero Hydroelectric Project Cost Estimate (USS -        January 1996).................... 43
Table 4 1     Long-term Rainfall (mm)..............................................................................................  47
Table 4 2     Seasonal Rainfall Distribution..............
48
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
Table47        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 Water Level Elevations (ma;])
.... ..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 (m3/s per 10,000 hectares)
Table 4.J7 Unit Cosib (January 1996)................... ...................... 65
Table 4 18     Itang Irrigation  Project Cost Estimate - US Dollars (Jan 1996) Table4.19      Itang Irrigation  Project Annual Costs - 1000 USS (Jan 1996)
Table 4 20 Economic Return of Crop (Birr/ha)............................................ 71
Table 4 21 Cropping Build-up (hectares).............................................. .......... 71
Table 4.22 Benefit Build-up (million Bin)................... . .................... ...
-.61
68
,69
72
TAMS-ULG Baro-Akobo River Buln Integrated Development Muter PlanPREFEASfBH.m STUDIES
3.5.3 Implementation Schedule
3 6 Economic Appraisal
VOLUME V
...<5
...44
4,
s■
4
i+r
®-
■
[TANG IRRIGATION PROJECT
4 I Im reduction
4.1.1    Project A rea...............
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 ,.-
4.2.5     Water Quality for Irrigation
t r - - i - + + •-
fi fa fa.4. fa 4 4
4.2.6
4.2 7
Land Resources.... . ................
Geology and Geotechnical.........
t- r <
4.3   Project Development
4.3.1    Agriculture   and   Cropping   Patterns.. 4.3.2    Irrigation         Water         Requirements 4.3.3    Reservoir          Operation          Studies
- + -■
4+
4.3.4    Irrigation
Infrastructure
4.3 5
Estimates of Costs and Benefits
. . fa. fa 4 4 .
4 4 The Recommended Project
4.4.1    Project           Description.,.....
4.4.2    Cost
Estimates
4.4.3
4.4.4
4.4.5
Implementation Schedule...
Economic     Analysis............, Environmental A ssessment
*■
.APPENDICES
Figure 1 1 P roj ect Locat ion Ma p
FIGURES
Figure 2-1 EELPA Peak Power Demand Forecast
Figure  2  2  Geba  River  at  Geba-A  Dam  Site  Yield  Curve  at  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 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 Baiin Integrated Development Muter PUnprefeasibelity studies
VOLUME V
1. background
1.1      Master Plan Studies
This  volume contains  the ^feasibility  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 to 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 rev iew of lhe 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  1  contains  the  Executive Summary,  and  the  maps  are  presented  in  Volume  4  The  major  water  resources  projects  are reviewed and evaluated in Annex IH - Irrigation Projects and .Annex 1J - Hydropower Projects Three projects were selected for pre feasibility level studies (Figure 1.1) They arc:
the  Geba  Hydroelectric  project  on  the  Geba  River,  located  approximately  60  km  east  of Gore in the upper reaches of the Baro basin,
the  Gumero  Hydroclectnc  project  on  the  Gumero  river,  located  20  km  west  of  Metu  also in the Baro basin and,
the Hang Irrigation project with a dam impounding the Baro river 30 km downstream of am c a and an irrigation area on the right bank in the vicinity of It an g
TiMS-LLG Baro-Akobo River Bum Integrated Development Muter Plan
Chapter 1JPRE FEASIBILITY' STL DIES
VOLUME V
1.2 Selection of Candidate Projects
schemes have been reviewed
Interconnected  System  (ICS)  The  Master  Plan  studies.  detailed  in  Annex  I  J,  have  identified several projects with attractive economic returns
In the range of medium to large-scale projects, the Baro and Geba projects have the potential for about 210 MW and 170 MW, respectively, at 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  al ihc  location of steep reaches  of the river
Both  projects,  therefore,  present  the  possibility  of  staged  development  if  the  economic  and.1   or financial conditions dictate such an approach In this case, rhe Geba project would be preferable since the two stages of development (100 \'W and 70 MW) would be tn the medium-size range
With the Baro scheme there is a large disparity between the size of projects, with the initial single stage  being  either  a  40  MW  or  a  170  MU’  power  plant,  the  latter  being  already  a  large-size project  Furthermore  it  appears  from  the  only  available  topographic  map.  dated  1977  at  a 1.50.000 scale, that the reservoir area of the Baro 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 studies.
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 studies  (Annex  1J) have identified several small-sizc  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 and Baro, consists  of a regulating reservoir in the upper reach of the Gumero River and three power diversions in cascade downstream of the dam talcing advantage of the steep profile ot 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 the third (20 MW) in year
2018  The  project  cost  appears  to  be  significantly  lower  than  lhe  alternate  sources  of  electric power in the basin which are mainly isolated diesel plants
TAMS-ULG B.ro-Akobo Rh
er Baim tatef raled Oeve opm<Ilt M„ter pkn
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Chapter I
2PREFEASlBLLm' STUDIES
VOLUlUp V
13 Study Limitations
When the three projects for prefeasibility level studies were identified in the course of the Maste 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 provided 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 intervals at the location of all the structures, and
cross  sections  along  the  alignments  of  power  canals  at  an  approximate  rate  of  three sections per kilomeire
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 various 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 I 50,000 topographic maps.
The studies performed therefore in the course of these prefeasibility level evaluations have a number of uncertainties, mainly 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 hydroelectric projects and of basic geology and geotechnical information for the power and irrigation projects 
For each of these projects, the reservoir ability to regulaie the river flows on an inter-seasonal basis is a major factor in the viability of the project. Similarly, the detail of the topography at the dam sites at the location of the major structures and along the long power canal routes for the Geba and Gumero Projects, will need to be improved signiGcantly for an adequate assessment oi the civil work required and to better define the quantity and cost estimates.
TAMS CLG Biro-Akobo River Bum Intejnitd D« k>p ,«,  Mailer P|
tnt
3
ln
Chapter 1PREFEASIBILITY STUDIES
VOLUME V
2. GEBA HYDROELECTRIC PROJECT
2.1 Introduction
2.1.1    Project Concept
In the review of the hydropower resources  of the Baro-Akobo basin (see Annex  1 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 Baro 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 river 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-1 (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  well 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-Bedele 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 '’SOO At  the  site  itself  the  river  is  at  elevation  2130,  falling  to  1840  and  1500  at  the  powerhouses  for Diversion I and Diversion 2 respectively.
2.1.3    Power Planning
At present the easting countrywide generating capacity  of approximately  400 MW serves  a total population of million people Of this  total capacity, the installed capacity  connected to the Inter Co ed System (ICS), which does not serve the whole country, is 385 MW The
TAMS-ULG Biro-Akobo River Bum Integrated Development Mailer Plan
4
Chapter 2PEAK POWER DEMAND (MW)
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 meters
Area in km2
La^nd — —         trirtal
Geba Reservoir
■
After Sed mentation
Area-Capacity Cu^
Figure 2-3
JPREFEASIBILITY STUDIES
VOLUME V
An ambitious  program of power generation development, both hydropower and thermal, is planned to meet the growth of demand, taken by  EF.LPA 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 Figure 2-1
The hydroelectric  power studies  performed for the purpose of this  Master Plan (Annex  1 J) have shown that Lhe Geba Hydroelectric  Project could be a candidate to be integrated into the ICS as early 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
2.2.2      Hydrology
The Geba project is  on the Geba River and has  a catchment area of 1,086 km2 at the location of the storage dam The hydrometric  network  of the Baro River basin, which includes  the Geba 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
2
2 respectively
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 t he catchment, and
stochastic modelling to generate long-term (74 years) monthly flow series Table 2 1 shows the long-term monthly average at the dam site
TAMS-ULG Biro-Akobo River
Chapter 2prefeasibujtv studies
Table 2.1 Average Monthly Flows at Geba Dam (m /s)
[ J anilol >
I reoruan
7.2
4.0
J
March                               25------------------------------- Ann!                                     39
July August September
October
698
95.7
1 10 .0
65.9
—-------- -
Nhv
106
November
21.0
June
' 28 2
December
98
The  mean  annual  discharge  is  35  7  m3/s  or  1,127  mcm  with  a  strongly  pronounced  seasonal vanation 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  analysis  was  performed  to determine flow for different return periods at the Geba site The results of this analysis, (.Annex
1C), which are shown on Table 2.2, were based on the Sor River gauging station
Table 2.2        Flood Frequency Analysis at Geba Dam
Return Period
Discharge (m /s)
3
1C vear
292
100 vear
462
1 500 year
1 631 
Fot the meteorological and rainfall gauging stations located in the vianitv of the basin, a statistical analysis  of the maximum daily  precipitation was  performed Applying the Hershfield methodology, as indicated in .Annex 1C - Flood Studies of the Master Plan, the precipitation daia 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
Stations
24-Hour PMP (mm)
Chora
377
Gore
400
Metu
336
Hurumu
501
Based on Uns analyse .he 24-hour pan, PMP for :he
400 mm For .hepurpose of aha,. prefea*hty study,. amplified HEC-1 model was develop*1
„*
10
to be I. I4V m /s.
hydrograph ° ’
f h'
design Th' discharge is esima'*1
°
ITiere  is  no  available  data  on  suspended  sedunent  in  the  vicinity  of   sjte   A   discussion   of  the sedimentation estimate for all renewed reserves« presented m .Annex lF?o the Master Pl*1
TAMS-ULG Baro-Akobo River Baiin Integrated Development Master
6
Chapter 2PREFEASIBILTTY STUDIES
VOLUME V
Report   For   the   purpose   of   planning,   rhe   reservoir   operation   studies   considered   the   accumulation of sediment in the reservoir al an annual rate of 1,320,000 mJ
2.2.3     Site Geology
The damsite is  located on Basalt The ARD CO-GEO SER V 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, sirip 16, photo 1323. and is  not stereoscopic  The whole area is  forested with gentle relief and rolling 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   of   large   areas   of   outcropping   rock,   but   possible   basalt   outcrops   are   present   to   the   north of   the   site   in   the   Kombo   area   which   might   provide   a   rockfill   quany.   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  basalt  and  partly  in  hornblende  and  biotite  gneisses  The  powerhouses  are 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 ranee 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 nver some distance downstream If a field survey  were to indicate that this  fault would present no hazard to a spillway  constructed on the nght bank, this  would result in a much shorter chute this option should be considered after further investigation
With a 275-meire head available at the end of a 3.500-metre long canal, and considering a drainage; area of over 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 mVs, it is  not considered
considering5
depending on other drveJopment options in the basin, it could be worth
TAMS-ULG Bam-Akoho Rn
[ hUgra(t!<j
M«Ur P|.n
Chapter 2
7PREFEASIBUm STUDIES
v °UiMiv
,  .V,  nniv  toDoeraphv  available  is  at  a  scale  of  1:50,000  with  20.^
As previously noted contours From thts topogr) y 
selected is appropriate, and the quantity and
and (arger topOgra?
”"xx™ '"ii •* *•»* • “re Konon”“i si,e be/°i,nd- °r in any X—■*-of “and layou' be made
2.3.2   Reservoir Operation Studies
As  indicated  above,  the  reservoir  will  regulate  the  river  flow  to  be  used  at  two  downstream hydroelectric  power  plants  The  HEC-5  computer  model  was  used  to  esttmate  the  yield,  or flow that can be guaranteed by operating the reservoir so as to release a constant flow For the purpose of this studv. the vield was defined as the constant monthly discharge for which the long, tennaverage  defiat  is  2%  of  the  yield  (98%  reliability).  The  HEC-5  model  performs  a  monthly 
routing of the 74-vear long flow time senes  at the dam site Figure 2 2 shows  the yield in m3/j of the Geba 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 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 thu computation for the reservoir with a maximum operating level at El 2,170 Table 2.5 shows the 74-yeai long flow- time series used with the HEC-5 program
Table 2.4 Geba Reservoir Firm Flow (m /s)
J
ror eacn or tnese 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 and second power diversions  are 275 metre and 175 metre respectively  Table 2.6 show's  the annual firm energy  generated by the project for each of d* selected maximum operating pool.
TAMS-ULG B.roAkobo Rher Bllin
Cb»p** '
r
88SS8B8S8itgB8g83a4aaaajja3
-* m
Tabic 2-5 Monthly Flowc at Get* Oom (m3/»ac)
Jm             Ft*         Mm
44          19         22
• 5          IS          22
95          15          22
52          36         11
09          04         0 6
26          20         1 7
73         S3          00
Ay *»y**
39         46       17.1
*d M
474          907
634
Od
369          68          73
24          11           IS         81 ?       1079
24 11 15
23 34 208
09 27 14 3
911 1062
436 9*1
509 389
820          742        19 0         99
822         74 4        19 0         99
1580          <18         3.7         114
41.7 125 53 39
49       19 2        416          M1        111.1       103.3         451        14.0          66
15       14 5        635
1062        1275       100 9         588        223         9.2
e.7 60 41 11 35 37 9 648 106*
to 1 109 23 54 47 16 2 550 915
4«          19          22
39          46        172
477          913
117.7 991 210 62
7149 1527 392 19 2
839         39 1          69           74
243         SO         60       14.6       376        251          920         94 1        1424          972        441        161
74          54          00
239 SO 58
IS        146        649       107 0        139
•04 6          806        227          93
143         Ml         245         619         92C         132           95 0       47 0        177
• 4          14         21          23          10          14         610        •06 6
03 01 02
7.2 S3 00
7.3 55 06
03          08          44
159          124
61 1 735 189 97
130 39 1.6 12
1.5 14.5 <30 104 4 13 5 1023 564 221 91
01 34 64 MO MO 152 0 440 213 10 7
25.72
31 22
31 K
3592
14 49
37 01
43 25
4161
51 85
25 69
5019
4398
«9 2*
30 U
451
42.93
.10 45
13
0.6
09
13
39
20 6
736
577
802
181
76
57
2OM
73
S3
00
IS
14 7
64D
106 0
134
me
603
224
92
43M
27
21
16
46
til
427
960
113 3
104 4
<0
143
67
37 78
25
19
17
45
17 9
41.1
•25
1081
100 5
442
13 8
55
3635
•3
34
21
23
10
1.4
®7
1082
807
731
18 7
97
30 71
27
21
1.8
46
18 5
424
•54
1126
•03 9
M7
14 2
67
37 M
224
4?
56
137
36 4
235
Ml
M2
133 3
91 0
450
170
47 19
59
41
39
22
69
213
470
709
897
81 7
137
52
26.71
26
20
17
46
•62
41 6
936
1106
’Oil
448
14 0
65
3685
59
41
19
22
68
292
469
707
695
615
137
52
26 63
<6
19
22
39
46
171
47.4
90T
S3 4
389
66
73
25 72
95
35
22
24
1.1
15
H7
1079
820
74 2
190
99
3122
95
35
22
24
11
13
619
1062
622
744
190
99
31 30
52
39
11
23
34
208
434
913
IMO
638
24 7
11 4
35 92
09
04
06
09
27
143
509
389
41 7
125
S3
39
14 49
26
20
17
46
182
418
54.1
111.1
•023
aS 1
140
66
37 01
74
54
00
15
147
642
106 4
139
1042
60S
225
93
4374
47
60
41
11
15
379
Ml
1091
1177
991
710
62
41 81
237
49
56
142
Mi
244
M<
91 7
1387
946
461
176
49 06
97
45
24
11
SS
172
465
682
783
407
128
56
24 51
M3
SO
40
14 6
178
251
920
941
1424
972
481
11.1
SC 39
12
65
36
44
95
346
631
M7
1065
668
263
96
33 03
46
29
20
24
145
373
76.1
1170
1225
684
153
SB
39 32
94
3S
22
24
11
15
623
1080
626
750
161
98
3153
109
117
25
56
11
17 4
Ml
979
238
1634
419
205
58 47
29
SO
20
09
•7
456
792
1022
131 0
M9
305
189
<2 66
229
49
5«
137
369
236
Ml
M5
1340
815
453
17.0
47 43
105
11 3
24
17
41
169
571
952
223 3
1516
406
xo
53 91
22
24
29
25
39
122
51 4
66 D
965
647
212
7.7
2128
71
27
26
55
117
41 8
976
1056
104 0
813
167
94
40 63
HO
111
25
51
52
177
901
1000
Z348
166 9
429
210
56 66
71
5.3
01
01
34
62
233
657
147 9
428
207
10 4
29 M
72
46
69
36
81
324
313
625
627
484
71
33
24 98
29
50
20
06
68
464
715
1013
139
642
303
117
<2 29
22i
46
14
133
344
228
<15
855
13 3
M3
437
114
45 77
7.7
24
03
31
99
211
966
106.0
970
260
24 2
92
3206
46
29
20
IS
14 6
37 6
78 6
1181
136
TOO
15 4
58
»67
4.1
24
03
75
186
103 1
174.1
2220
2235
967
106
48
7277
12
•4
36
44
IS
345
06
644
1060
666
262
95
E 90
10
53
43
19
107
352
61 1
1061
*63
346
275
101
52
39
32 36
11
23
34
206
418
91 7
1586
64 1
24 7
7.1
11.4
36 06
27
26
55
156
414
976
105 3
KB 7
61 1
40 72
99
166
94
46
24
19
56
17.1
472
703
796
414
29
130
SI
24 93
20
17
45
111
414
932
1100
1013
446
32
13.9
85
13
3666
26
12
8.4
225
402
1030
1452
68*
4.0
131
46
41
34 42
40
2L2
70
at
477
719
707
Cl
22
139
53
24
27 09
71
24
31
14
121
509
<7.2
953
679
209
06
26
77 96
to
14
41
220
?I6
616
M3
19.4
25
81
61
12
22 38
10
2.3
30
260
572
784
Ml
419
137
39
79
27M
19
21
11
21
144
419
855
690
337
95
125
35
99 |
2318
22
24
1.1
15
620
108 4
624
17
746
191
61
99
31 37
43
1.1
56
384
869
110 5
1192
100 4
22
212
43
62 I
4215
25
19
56
203
MS
961
614
4! 4
56
4»
11.5
154 1
2673
27
11
52
446
725
1005
111,7
57,0
49
132
51 1
35 60
11
22
39
46
17.1
476
91.1
44
837
390
69
37
24
74 |
2562
76
155
276
5i5
927
1015
459
26 8
72
53
161
3314
00
15
145
632
104 6
139
1026
723
596
222
390
246
9
4307
.3 93
13Q
78 11
69 78
95 57
10896
65M
2099
IT
3670prefeasibility stldies
Tible 2.6 Geba Hydroelectric Project - Annual Firm Energy (GWh)
v °limev
Maximum Reservoir Level
Diversion No. 1 Firm
Diversion No. 2 Energy (GWh/   j
Vr
-------------- -------------------— Fl 2160
386
245
El 2165
.
514                                         H
327
El 2170
588
374
El 2175
620
394
2 J. J Access and Transmission Lines
As  previously  noted, the main storage dam at Geba is  located 18 km south of the Metu*Bedde 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 l/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 part of the permanent access, but whether these could be constructed as part 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-Bedele-Jimma highway, or 100 kilometres  overland However, it is  noted that there are plans  to extend the ICS to Bedele, only  35 km away  by  year 2000. Ln the other direction, the existing Sor-Metu-Gore-Gambela 66 kV line is  60 km away. For the size of the project considered at Geba, i.e, 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 Project 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 flo*5
As of the 1977 survey, the 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 that 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 spiDway 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 abuiment
it appeared to be; more appropriate to put the diversion tunnels on the right abutment. They cross the inferred fault near the downstream portal, but at depth. .An dlowance for additional tunne. support at this location has been made m the cost estimate One of the tunnels will be us^
tor making releases to the power projects downstream, and
since a mu ti evcI Outlct
||
j s required
for environmental reasons, locating the tunnels on the right bank avoids .mergence between d*
outlet tower and the spillway intake
° interference between
TAMS-ULC
River Ba.is
t>eveJo
prt)rnl
Cbupfer 2
IdPREFEASIBILITY studies
VO LU1 ME V
The two power diversions  are located on the left bank, al the heads  of falls, where contour canals of minimum length can be constructed to feed very  steeply  sloping penstocks  leading to the powerhouses  In the case of Diversion No. 1, the canal could be extended another 1500 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 an d Optimis ation
For the purpose of selecting the size of the project to be developed at the Geba site, cost estimates for four levels  of reservoir 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 rhe system load factor which is adequate io provide a fair evaluation of the project
The two hydropower diversions  downstream of the storage dam, are essentially  run-of-river projects  utilising lhe regulated releases  from the reservoir As  a consequence, for each reservoir 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 nol depend on the head created by  lhe 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 reservoir level selected is  at El 2145 Table 2.7 shows the main 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
Avg. Regulated Discharge (m'/s)
20 4                    27.2                    31 0                    . 32 8
Max Power Discharge irr, ,'sl
34 0                   45 3
51 7                   T 54.7
Diversion No IHead(m)
275                     275                     275                 T275
Diversion No 1 Capacity (MW)
73                      98                        112                     1 18
Diversion No. 2 Head (m)
Diversion No 2 Capacity (MW)
175                    175                  l!75                                     175
47                       62
—L75
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 (ERR) 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 lhe revenue from the sales  of firm energy  At the feasibility  level the optimisation will be done on the basis  of the incremental IRR
TAMS-ULC Barr>-A kobo Rbtr Batin Integrated Development Master Plan
Chapter 1
11PREFEASIBILm STUDIES
.As shown on Table 2 8. the cost for engineering and administration of the project h estimated at 10% of the total construction cost.
The cost of  operation  and maintenance over the 50 year life of the project were follows
0 5% for civil works
2 5% for electromechanical equipment 1 0% for transmission lines
^ Ve be*
e^
aiedaj
Revenues from the sales of firm energy were estimated at the rate of USS 0 06/kWh (h 19961
TAMS-ULG Bam- M«,b  River Bum
u
------------- ----- ------- .
e<J»«ehpmeatMuj(e(rpijio
Chapter 2
12
rTable 2.8
Project Optimization - Cost Estimates (US$ ,000)
Price Level : January 1996
Mai. Mor- Res. Layel              -------- —
El. 2J75
118 MW
niir klrt 1 In^f. Can
El. 2/150
73 MW
EL 2.165
MW
El. 2.170
112 MW
Div. Nc.2 Inst. Cap                         --------
47 MW
62 MW
71 MW
75 MW
Dam i App. Works _________________ Preliminary ------- ------- Main Dam
Access Road
3 061
12 219
2 600
3 569
15.602
2.600
r 4.194”
19,772
2.600 ]
-
Diversion Tunnel
2.421
2.421
2.421
4 958
24.B61
2 600
2 P421
Anillwd v
2.913
2 918
2.918
2.918
Low Le vs 1 O iri let                      ---------
250 ni jca
250
250 Lt? 154
250 38.006
Power Plant & Conveyance
Diversion No.jl
Preliminary
Access Road
Power Intake
6 186
7.897 .
8 857
9.272
346
348
348
349
0
□
0
0
Power Canal
7 476
7 476
7.476
7.476
Power Tunnel
0
0
0
o
Surge Shaft
0
0
0
0
Pressure Shaft
0
□
0
0
Penstock & Manifold
3485
4,643
5.300
5 600
Powerhouse i Equipment
Subtotal 47,425
Diversion No. 2
29.930
40.180 45.920 48.300
60,544 67,901 71.084
Preliminary
4 467
5.569
6229
6,522
Access Road
80
80
80
80
Power Inlake
0
—          o’1
0
0
Power Canal
6 729
6J29
6 729
6.729
Power Tunnel
0
Q
0
0
Surge Shaft
0
0
0
0
Pressure Shaft
0
0
“ol
0
Penstock 4 Manifold
1.118
1.490
1,700
1.798
Powerhouse & Equipment
21 655
28.830
33,015
34.875
■
47.752             50.004
Transmission
Preliminary
Switchyard Div. No1
5 265
5.307
5,331
5 342
1i 006
Switchyard Div, No2
1.163
1.250
1 286
Transmission Line
842
967
33.250
,
33.250
1 042
1 075
33,250
33,250
•f
40.954
Reservoir Ana Clearing
Population Relocation
2,160
3,054
3 948
t
5,5 08"|
700
700
700
TOO I
Physical Contingencies f2n%i
Subtotal        148,366          175.043
193 328
206 258
29.673            35.009
tngineenng & Administration (10%)           17.804            21 005
30 666
41 252
23 199
24.751
I                        Total Direct Cost      195,843     231,056      255,193      272>60“|PREFEASTBILITY STUDIES
Voliimev
Based on these assumptions, the IRR of the four selected schemes were computed as s^ Table 2.9
Table 2.9 Project Optimisation - Internal Rate of Return
Maximum Reservoir Level Diversion No 1 Inst Cap Diversion No 2 Inst Cap Total Construction Cost (USS mil) Annua! 0 & M Cost CUSS mil) Finn Energy (GWh/yr) Annual Revenue (USS mil)
1RR (%l
El 2160 73
47 1958
2 80 631
37 86 14.4%
El 2165 98
62 231 9
3 49 841
50 46 16.0%
El 2170 112
71 255 2
3.91 962
57 72 16 4%
El 217s 118
75
272.3
4 12
1,014
60.84
16 3%
On that basis, the Geba project with a maximum operating pool at El 2,170 was  selected The number of units  and the unit size were selected based on the fact that, at the present, the largest unit size in the ICS is  approximately  30 MW and that the total installed capacity  of the Geba project would represent a 48% increase of the existing installed capacity  of Ethiopia If the project were to come on line in year 2004, it appears  appropriate to select unit size of about the 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 MW for Diversion No 1 and 72 MW for Diversion No 2
2.4        Environmental Assessment
The Geba dam site is  located in the Hlubabor region near the eastern edge of the Masier Plan area, on  the Geba Rivet, 120 km upstream of its  confluence with the Birbir River. Its  geolog)' 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 Gobi River, where two in-line diversions, power canals, and powerhouses  would use its  flo'v t0 generate electricity. The first diversion is  4 km downstream of the dam. the second 17 km Tl*e respective lengths of their power canals are 3.5 and 6 km
Positive impacts
TAMS-ULG B.n>Akobo River B«ib In^raud
14
!PREFEASIBILITY STUDIES
VOLUME V
Flood control A flood surcharge volume of 300 million cubic  metres  (mem) is  provided Flood attenuation will undoubtedly  occur as  a result of normal reserv  oir operations  However, flood 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  Selkhozpromexport nor ARDCO-GEOSERV provides fisheries  estimates  for impoundments  in the upper basin Selkhozpromexport (1988) estimated that the Abobo reservoir tn the lower basin could produce an annual catch of 100 t for its 2 2)0 hectares  reservoir This  result cannot be extrapolated to upland reservoirs, however, without further study
Fueiwood. .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 site has  not been surv  ey  ed 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   Geba   reservoir   (66   km ),   this   translates   into   a   potential
2
fuel wood supply  of between tonnes  At 5 Birr per 20 kg bundle of fuelwood, 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 13 2 million)
Recession agriculture and gratins 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 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 soils, vegetation, wildlife and wildlands, fisheries, climate, and human population in 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    (he following
■ Construction camp,
• Roads, and
Dam and appurtenant works. Dislocation of people.
Loss of land
TAMS-ULG Baro-Akobo (liver Bin in Integrated Development Muter Plan
15
Chapter 2preffasibility studies
volume V
. 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
Construction   camp   Construction   camps 
u
sually 
compri
se   q
uarte
rs 
for  bet
ween  20
0   and   600   men,
and   contain   showers,   cooking   facilities,
toilets,
gener
ators,
fue
l
dumps,
cement
machines,   parking
areas   -   everything   needed   by   a   sma
ll
town.
Their
des
ign
is 
usually 
tempora
ry,   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 eleclrical 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 w-ater 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  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 t*
used after its decommissioning If it is to continue in use, then primary 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 construction of one stream crossing The stream crossing, depending upon its type, could cans4 expansion of the channel and disruption of aquatic life. Roads have been shown to be important contributor to soil erosion, primarily because they concentrate and distribute runoff channel flow rather than as uniform overland or subsurface flow
TAMS-ULG Bum-Akol* River [lrtcSrltH Development M^rTpL^
Ch*P<<r2prefeasibility 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 safelv  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 historical or culiural significance unless ihe means to control trespassing io 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   Soil   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
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 location of hydraulic structures The erosion control measures should be in accordance
with the following principles:
size of the disturbed area is  small or its  duration short In some instances  stabilisation can take place as  part 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   lhat   filter   sediment from   runoff   or   that   detain   runoff   so   that   heavy   partides   will   settle,   It   includes   the   use   of materials such as silt fences, straw bales, brush barriers, and sediment traps and basins
onZy   the   sediment   and   runoff   from   the   sue.   For   this   discussion   we   arc   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
Darnand appurtenant works.
TAMS-ULG Bini-Akobo River Bwin [nU(,r.u<i Otvclopment Muter Plan
Chapter 2
17prefeasibtlity STUDIES
v °lumEv
With   regard   to   (Aversion   works,   spoil   from   tunnel   borings   should   be   removed   to   a   protected   Slt isolated from streams, rivers, and the reservoir.
Dislocqnonofjteople    The    study    by    ARDCO-GEOSERV    (1995)    shows    that    28    households 
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 year If relocation costs  are taken to be equivalent to 3 years’ revenue plus  assets (estimated' at USS 500), the)- become USS 620 per household or USS 17,360 for the 28 households
Loss  of land The reservoir will impound 90 km2 The worth of its  standing timber as  dry  woody biomass  has  been estimated in a previous  paragraph The previous  assessment shows  that 2A 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  7,000 Birr per year (USS 1,120 per year)
Loss  of  historic,  cultural  or  aesthetic  features  These  components  were  not  assessed  at  this  levei of study 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 tune It is a subject that will require attention during feasibility studies
Proliferation 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
DerenQgman_<2/ water quality’. Water quality  is  affected when large amounts  of tropic^ vegetation are flooded by  new reservoirs  The two important parameters  to the process  are the amount of biomass  and the residence time of the water in the reservoir From a totally  empiric* 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 nsk  category  For the purpose of this  prefeasbility  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
TA MS-U LG Baro-Akobo River B>lln Inlq-rrud D^kopmTn] Mailer P|«
Clmj)ier7
(8PRE FEASIBILITY STUDIES
VOLUME V
Riverine
fisheries
The
reservoir
may 
interrupt
fis
h
migra
tions,
but
this 
has 
not    been    dir
ectly 
assessed
during
the
course   of
this 
or
previou
s 
st
udies 
A   fish
lad
der
and
hatchery   should
be
considered
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 nsk  of malana and other diseases  related to mosquitoes, gnats, midges, and other insect carriers  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 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 reservoir 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 Bulinus
Infection   would   affect   people   who   used   the   reservoir   for   recreation   or   as   a   source   of   domestic waler   The   greatest   nsk   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 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. Seikhozpromexport (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
J
Selkhozpromexport (1988) reported the absence of the mosquito carriers  of Leishmaniasis  in the lower basin There is  no information about their presence in the vicinity  of Geba reservoir or, indeed, then 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 waler Provisional minimal continuous  releases  from the Geba Dam and its  in-line diversions  are computed at 8 percent of mean annual discharge or 0.70n?/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 computed a qw uration curve based on mean daily  discharge, from which minimal flow requirements  are usually estimated
TAMS CLG Buro-Akobe River Basin Integrated Development Muter Plan
19
Chapter 2PREFEASIBILm STUDIES
v °l%
Increased land pressure. The Geba reservoir will requi
re the relocation of ?»
currently resident in its 90 km  area The development
?
is unlikely to attract an i fl "°    ^
USe
into the area other than for the dam construction
u*
2.5      The Recommended Project
2.5. / Project Description
The Geba Project storage dam is  located on the Geba River at the downstream end of a wj^ 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 km1, 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 eanlift 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 makes power releases  The control shaft could be constructed before diversion, but gate, hoist and seal frame installation, and second stage concreting, will have to be done after diversion, with the other tunnel remaining open to pass  the river 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 service, the other emergency, will be provided just downstream of the selective withdrawal shaft The service gates  will be dosed during operation of the selective withdraw^ gates  so the laner can always  be operated under balanced head. A small stilling basin is  provided levels a0Wl1StrCani end of tunnel for ener8y dissipation during operation at high reservoir
The first power diversion is located 4 kilometres dow-nstream of the dam The diversion weir is an ungated concrete ogee section. 80 metres long On the left bank a canal intake structure will be buih, equipped with 10-3x1 5 m sluice gates. Downstream of the intake structure, the canal- sraed for 51.7 m/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-lin*1
u-metre wide accessrand 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 tl* roct n may prove advantageous to size the canal for the mean ddy power flow and provide a
re-regulating resen ou at the head of the penstock for daily pondage
The penstock is 3 2 metres in diameter and 700 The maximum plate thickness is 30 mm
TAMS-ULG Bin.Aicobo
metres long to develop a total head of275
—
2(Jprefeasibility studies
VOLUME V
At the powerhouse the penstock will feed a mamfoid 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
rhe turbine, each branch pipe will be provided with al 40 m diameter inlet valve io 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 rhe normal minimum tailwater level Tailrace will be very short or non-existent
The four transformers  are anticipated to be located at the powerhouse above the manifold (on the hillside) with the switchyard located on a flat 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   Lhickness   for   this penstock   is   20   mm   At   the   powerhouse   the   penstock   will   trifurcate   to   serve   three   24-MW   units in   the   powerhouse   Each   Francis   turbine   will   be   provided   with   a   I   50   metre   diameter   inlet   valve and   will   have   a   runner   discharge   diameter   of   1   30   metres   The   12-pole   generators   will   rotate   at 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 the 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 Vi 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 GE- 12) to obtain quantities  appropriate to the prcfeasibility  level. In 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 2.10 These were derived from bids for a similar project subjected to international competitive bidding in .Africa and
outh America and adjusted to a common January 1996 price level
TAMS-ULG Baro-Akobfl River Birin Im egrated Development Master Plan
Chapter 2PREFEASIBILm’ STUDIES
Table 2.10 Unit Prices (January 1996)
Unit
1        Unit     Price^~^
Item---------- --------------- -----------------------------
Common Excavation_________________________ Rock Excavation           ._______________________ PnriaJ Excavation
Tunnel Excavation
Borrow Excavation - Common
m
m
3
f 3 62 1*9 04 ! 6*78
T
>
----------------
m’
1 50.84
3
m 1*339
Borrow Excavation - Rock
m                                     1 4 80
J
Mass Concrete
9039
Structural Concrete
129.94
Concrete linine (tunnel)
m'
203 38
Formwork
50.85
Steel Reinforcement
T                                        1,242 90
Unprocessed Fill (placement)                                      m                                   1
5
226
Processed Fill (placement)
m                                      6 78
Filters
m'
16.95
Drains, Transitions
m5
11.30
Impervious Core
T3------------------------------
m 565
t
■—
Drilling (confined space)
m               79.09
Drilling (open space)
m                                     56 50                     _'
Grouting
T                                      564 96             J
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 2-1 and summarised in Table 2.11
TAMS-ULC Baro-AkoboRiv" B““lDlfRr>,rd
Chap<f r 2
22
JPRE FEASIBILITY STUDIES
VOLUME V
Table 2.11 Geba Hydroelectric Project Cost Estimate fl’SS - January 1996)
_________ _ __________________________ —__________________________ ■ —»
& Annurtenant Works
------
Civil Works
35,430.000
EatiiomenE
1 420,000
Power Plant and Waterway. No 1
Civil Works
15.320.000
Ecuioment
51,970.000
1  Power Plant and Waterway . No 2 
_
Civil W orks
19.850,000
_____—-j— — - —-— —- Transmission Lines
Eq*uip*ment
36,000.000
31.500.000
Subtotal
191.480.000
Contingencies (20%)
38.300 000
Ene & Adm (10%)
22,980,000
I Total Construction Cost
252,760.000
2.5.3 Implementation Schedule
Il is  anticipated that feasibility  studies, design and preparation of bid documents  for the Geba Project would require about 234 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 stan 36 months  after commencement of the feasibility  study  Depending on the electric power demand at the time, 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 capital 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   show's   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 will form part of the ICS and therefore should be evaluated as a candidate project in the generation expansion plan of the system Essentially it should be
emonstrated that the inclusion of the Geba project represents the least cost expansion plan for the system.
TAMS-ULG B*to-a kobo Rjver Buin integrated Development Muter Plan
Chapter 2
23PRE FEASIBILITY STEWS
Al this time the polio in the power sector is in transition from the consideration of large proj,o S »»d Chemoea-Yeda to medium-sized projects such as Gojeb and Tek«e
consequence there is no defined least cost expansion plan of the system The next best opti^ he economic appraisal is to determine the long run marginal cost of energy and to use
XaJuate benefits for candidate projects Studies into interconnecttons with neighbor, countries have used a value orUSS 0 06 per kWh as the long run marginal cost of energy. value was used for the present assessment
As a check on the economic strength of Geba, comparison was made with other projects u ru consideration for the expansion of the ICS, using such parameters as the unit energy produ cost and the cost of installed capacity
v °U’Miv
As  demonstrated in Section 2 3 .5, the economic  internal rate of return of the Geba project, usinc 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 (LISS per kW)
Geba I and II
Gojeb
Aleltu East I
Aleltu West
Halele-Werebcsa Chemoga-Yeda 1 & II
1391
1740
2053
2865
2400
1816
It  can  be  seen  from  the  above  that  the  Geba  project  compares  very  favourably  with  any  alt  emaove hydropower projects presently under consideration
Finally   the   low   energy   production  cost  for  the  Geba significantly cheaper than any thermal plant option.
project, at about USS 0.038 per kWh. is
TAMS-ULG Baro-Akobo Wv.r Eauh
Chapter 2
JJ
___________prefeasibility studies
VOLUME V
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 Mew
The project consists  of a regulating reservoir downstream of a relatively  steep area in the upper catchment of the Gumero, and three 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 thiee 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 it is  needed to meet the growing demand. Alternatively, as  EELPA has  already  initiated 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 Gumero 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 Birbtr 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 at about elevation 2000, At the site itself the river is  at elevation 1580, falling to elevation 1340, 1120 and 800 at the powerhouses for Diversions 1, 2 and 3 respectively
3.1.3      Power Ptanning
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
onga for a total installed capacity of3.19 MW There are also two hydroelectric projects in the
TAMS-TLC B.ro-Akoto River Ruin Intetrlted Ikveloptncnt Multr Plan
Chapter 3pre feasibility studies
votlm
ev
h,dn
at   Sor   (5   MW)   and   near
Mizan   T
eferi   (800   kW).   Globally 
for   the
three
regions   c
ov
enn&
tiie
Baro-Akobo   basin.   Wollega.
Sor   and
Bonga,   the   total   electric
ity   sales
in
1
993   were
8.?J
GWh
Projects   for   these   regions 
average
growth   rates   of   7.4%   fo
r   energy
sale
s
and   5.5
%   for
neak
power  demand  (Figure  3  1)
over  the
next  twenty  years.  Jt  is 
anticipate
d  tha
t
the  peak 
p Ow&
demand  in  2020  wiE  reach  61  MW.  In  that  context,  it  is  expected  that  a  project  such  as  Guw with   the   potential   for   an   installed   capacity   of   approximately   50   MW   would   be   a   suitable power   project   for   the   year   2020   horizon.   Furthermore   the   Project,   by   its   nature,   a   cascade   of three  hydroelectric  installations,  is  well  set  to  be  staged  and  to  provide  peak  power  as  the  region demand  grows  It  should  also  be  noted  that  EELPA  is  planning  connection  to  the  ICS  in  the  neaj 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  conlours of 10 metres
3.2.2 Hydrology
The Gumero storage dam is  on the Gumero River and it has  a catchment area of 443 km7. The hydrometric  network  of lhe Baro River basin, which includes  the Gumero River, is  poor with 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 km1 respectively  There is  one gauging station on the Gumero upstream of the site with a significantly small catchment area (106 km )
The   river   flow   al   the   location   of   the   dam   was   estimated   in   accordance   with   the   methodology developed m .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 Tabie 3 i shows the long-term monthly average at the dam she
Table 3.1 Average Monthly Flows at Gumero Dam (m’/l)
1
January
February March April___ May June___
L46 
, L00_______
0 63_____
0.76 JZ
I Z1EZ
F? 67
^August__
September
Octobet
November
December
TAMS-ULG B.ro Akobo Riv.r Batm Integrated Devetopment^^l^
Chapter JPEAK POWER DEMAND (MW)
YEAR
Baro-Akobo Basin
Peak Power Demand Forecast
Figure 3-1PREFE.ASIBILITY STUDIES
volume V
The long-term mean annual flow is 8 66 m’/sec or 273 mcm. Approximately 91% of that m (249 mem) occurs during the six wettest months of the year from June to November
Using the available flow records in the basin, a flood frequency analysis was performed to determine flow for different return periods at the Gumero site. The results of this analvf (Annex 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
Dtscliarec [m\s|
10 vear
182
] 00 vear
313
500 year
r 462
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  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
Stations
24-Hour PMP | mm l
Gore
400
Metu
336
Hurumu
501
^J
K
PO “ PMP for
area was estimated to
be 400 mm. For he purpose of thts  prefcasbiltty  study, a simplified HEC-1 model was  developed
to estimate the mllow hydrograph of the spillway  destgn flood The peak  dpchame 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 tn the resent
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   nsetvoir   was   estimated to be 674,000 m
J, 23 Site Geology
lorss ciie is on the Gumero River 35 km upstream of the junction with the Bifbir <X-e The dam site is shown ou the gtmlogtca! sketch map at 1
28 Xs o^Xonnen Basal. overling hombiende and biotite gnetsses On the
I and the published Gore sheet only gneisses are shown in the area The
geofoc^-a covered by 
photos, strip 14. photos 1584 and 1585. The area has moderate relief an . at the dam site The uplands in the vicinity of the dam site are culnv3bklt
valley sicfunded slopes No large areas of rock are seen immediately near the dam site,
__________  - - p^p.^Akobo RJvrr Bi*n» Interfiled Development Mwter Plan
F Al’*’
C»iap«er-pR EFEASlBIirn STUDIES
VOLUME V
Kimateb 6 north northwcst of the dam s’te- at Guracha Mountain, basement gneisses 
a PP ° . t foliation striations outcrop and a rockfill quarry here would be easy to develop The
r
slopes outside the steep valley nm reputedly have suitable residual clay for impervious fill
" Crit its mav also be available for a rockfill quarry No sand and gravel deposits occur in the area
®     . jjj] is recommended tor this site A diversion tunnel should be easilv constructed in
'^basalts or gneisses with support of shotcrete, wire mesh and rockbolts.
33 project Development
JJ./ 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 the 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 nin-of-river development at the Gumero 2 diversion site might be considered However, it does not appear likely that (he 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 the 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
quamity and cost estimates have been prepared accordingly When more detailed, and larger topography becomes available, it may well be that a more economical site can be found, or
' event a more realistic and economic layout and arrangement of structures can be made
Reservoir Operation Studies
hydroel^3b°Ve’the reservoir will regulate the river flow to be used at three downstream
flow, that
Plai"S Thc HEC*5 computer model was used to estimate the yield, or firm
Purpose of thj guacameed by operating the reservoir so as to release a constant flow For the
- erni average
was defined as the constant monthly discharge for which the Iong-
r °uiin8 of the aT" 1S 2% Of the <98% reliability) The HEC-5 model performs a monthly 
>  m /$
3      Of jv *On8 A°w time series at the dam site (Table 3.4). Figure 3 2 shows the
n
his curv e was °
river at the dam location as a function of the reservoir active storage
^8 levels '° estimate the yield of the reservoir for a set of maximum reservoir
crfijuui Integrated Development Master Pirn
Chapter 3Table 3-4
Monthly Flow* at Gumero Dam (m3/sec)
oct         Nov       Dec
Year
Jan     Feb     Mar      Apr      May      Jun       Jul                        $*p—
t<i tin   id "Vk    18 60       720       25f
53
54
55
56
57
58
59
60
61
62
S3
64
85
66
67
68
63
70
71
72
73
74
75
78
77
78
79
60
81
82
83
84
85
86
87
88
89
90
91
92
93
0.82    0 41     037     027      1.94      3 24    11.80    1520      2720      19 10       630       2.6f 1.64     1.24     037     0.85     4.85     1092    21 80   27 80    2S.70     2270       5.10      1 57
1 94    1 41    0 9?    0.65      164       759     1980    19.10     1460      1540        660       1 94
202     153    0.82     058      265     1073    21 50    21 10     2120     21.10     10,10       246
1 27     1 12     D56     058      2 58      5.96     1450    1960     24 10    24 9C       6.00      2 84 1 94     1.03    D 45    0.66      265       826    21.40    20 80    21 20     1900       8.10       265 1 83     1 12     045    0.58      264      9 03    16.90    30,80    30.90      I860        450        258 1.38    0 70     056     123      347     13.08   29.10    20 50    23 30     31.00     10.00       295 183     1 03     046     066      265       819     2090    20.60    21.00     1960       8.20      2 65
1,57 124 037 0.85 485 10.73 21.70 2760 25.70 22.90 5.20 1.67 202 1,53 OB2 0.58 2 76 10.80 21.30 2090 21 60 21 70 10.30 2 58 127 1 12 055 039 2.02 729 18 W 1980 2420 23 90 6.10 213 246 1 41 075 0.77 265 1053 20 40 36 20 43.30 29.00 640 2 95 228 1.53 093 0.96 2 28 10.15 20 00 36 20 37.70 26 30 5.30 2 65 1 53 1 12 045 OSfl 2.76 872 18 50 30 00 30 20 1840 4.40 246 213 1.41 075 0S8 1.19 968 1880 34 40 35.70 20-50 400 1.63 127 1.12 0.56 077 220 625 15 00 21 50 25 90 29 80 6 80 258
1 57     053      082    0.86      202      5.02    10.30    15 X      2520     1940       4 60      1.64 0 82     050      045    0.00      037       2.20       980    11 80    18.90    12.00      4.80     213 i 183     1.24    0.75    0 85      239      8 91     2270   23 X      1960     18.70      7.30      2 50
1 83     1.12    0.63     058      2.28      976    21.80    20 80    1720     14.00      8-20     321
093    0 50     037    0.55      396      7.07     1590    17.20    19.90    16.10      7.30      3.40
1 84     103     0.37     058      3.02      853    20 80   21 00    15 90    12,80      0.60      250
062     050     0.56    0 19      1.57      502    13 30    1620     23 30    13 90      640       321
101      124    1.01      235      653     11.59    20 50   24 80    21.60      800      290       3.02 1.01     0.91      093     0.46     1.01       293       980    1300     1900    14 90      470       1 94
1 27     083      075    0.96      202      4 67   15,80    1886     23 00    1670      640       4.03
127    DS1    1 01     0 56     1.75      286     1030    1320     22 30    1580       480      2.28
127     063     0.75     058      1-27     5.21     1050    15.90   23 JO    1900      460       1 38
0.93     Ofil     0,82     058      1.12      3.06    11.20    14 20    21 00    11.40      6.30     2.65
0.82     050      045     006      1.57      637    20 90    1090     15.70      600       1 70     1 46 082     0 41     0.07     085      467       6.64    14.70    18,00    16.80    15.00      500       284 1 12     052     0.26     006      000       1.62       670    13 <50 2270       9.70      3.90      1.75 0_K3   0.41    0.46     048      246       664     1200     1500    25,00    20 00      850       239 127     1.03    0.53     027      340     11 96    23 SQ   18 00   26.70    34.10    11.60     3.14 0.75    1 12     1 19    206      4 33      741     14 40    1810    21 60    12.60      420      441 2 28     141     0.63     096       450     1292    22.20    35 60    31.CC   15.30      2-90      1 38 075      050     0.93     235      1 S3      502     15.40    16.90   2210     11.40      6.30      4.031 127     0.91     0.26    056       246      5.71     14.70   1910    28.40    31.10      780      265 213     1.24    0.75     1.50     284     12.15    27.30    23 80    18.50    18 70                   239
8 70
1 63     124    0.75     DBS      239      8.72    22.30   j&J-uu
Avg
.
144 1.M 043 171 248 7.67 17 JO 29.H 23 77 11.79 8.27 2.54 j
Annual
3 06
744
1038 H         7 681
96$
867
9 01
10.03
11.44
903
T0.36
9 74
8.91
1307
1211
979
10 91
956
7 28
531
918
845
7.00
7 97
7.00
877
5 88
7.94
642
7.03
6.18
554
738
5.17
785
11.30 1
7.72
1098
7®
958
1MO
1.66Firm Flow (m3/s)
1
1
i
1
'
 " T
1
---
WThl ------
1
bOnwarFT
"------ f
3 66 fl
3/s 1
—
11
1
j
-------- «•
>
1
—r i
____
J
1
1
1
I
/
—
1
1
1
1
1
1
1
l'
/
/
—
—
-
1
—
1
1
L
_
r-
1
r— 1—i—
11J
1
11
2Q0                        400 
SOO
Reservoir Active Storage (mcm)
800
Gumero River at Gumero Dam Site
Yield Curve at 98% Reliability
Figure 3,2PREFEASIBILITY STUDIES
The active storage of each reservoir was determined as the storage above El 1,600
V °LljMl
v
account the accumulation of 50 years of sediment. The area-capactty curve of the Scdi ‘ *J reservoir was determined by the use of the methodology developed by Borland, Moody Table 3.5 shows the firm flow at 98% reliability for the three reservoirs selected optimisation of the Gumero project Figure 3.3 shows the results of this computation fOrt^ reservoir with a maximum operating level at El 1,610
Table 3.5 Gumero Reservoir Firm Flow (m /s)
3
Maximum Reservoir Lev el
Active Storage (mcm)
Firm Flow
El 1,605
92
6 50
El 1,610
244
7 80
El 1,615
488
8 20
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 mt 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 Level
Diversion No.l Firm Energy (GWh/yr)
Diversion No.2 Firm Energy (GWh/yr)
Diversion No.3 Firn Energy (GWh/yr)
El 1,605                             53 6                                     804
91.6
El 1.610 64 3 965 1099
El 1,615 67 6 101 4 1155
3.3.3    Access and Transmission Lines
As previously noted, the mam Gumero storage dam is about 9 km from the Gore-Gambela rofc in country  with moderate relief .An all-new road along such an alignment from this  road wot> appear to be the best choice for access  to the site An alternative would be to improve the existing Metu-Burusa road and build a new road about 4 km long from the Burusa road to th 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 probably be necessary, therefore, to construct an access road through difficult terrain and al°r; the right bank of the river, where all three diversions are located From the dam to Diversion is 8.5 km as the crow flies, 4.5 km further to Diversion 2, and an additional 15 km from Divers*01 2 to Diversion 3
Since the Gumero project is proposed primarily to generate electricity for use within the B^ basin, the transmission line should connect directly to the existing Sor-Metu-Gore-Gambela kV line, 9 km from the site However, at full development (all 3 diversions), the to> transmission line length would be at least 37 km.
TAMS-ULG Baro-Akobo River Baiin Integrated Development^aster plan
30
”cb»p«r 3Elevation in meters
Area in km2
Figure 3-3PREFEASIBILITY STUDIES
3.3.4    Project Layout
Based on the small-scale (1 50,000) topography, the dam. spillway and outlet works arrange
appears to be the most favourable The dam is at the downstream end of a marshy, almost"?
1-2 km wide plain where a substantial amount of storage can be developed with a low (3?
dam, and without infringing on existing development on the nearby hill tops
For the spillway 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 coii; present a hazard to the embankment dam, since rock is probably lower there than on the left
diversion tunnel also would appear to be shorter, but the lesser overburden could product
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 nv 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 1 50,000 map 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 geotechnici 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 lex-els  of reservoir were prepared The project-installed capacity  has  bed selected to provide a project plant factor of approximately  60% As  a consequence, for each reservoir 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 environmentally feasible, taking into account the estimated sediment deposit in the reservoir o>tf the life of the project On that basis the minimum reservoir lev-el selected is at El. 1,600 Table
3.7 shows the mam characteristics of the projects selected for optimisation
TA.MS-VLC Buro-Akobo River Buin Integrated Development Muter Plan
31
Chapur3PREFEASIBlLrn STUDIES
VOLUME V
FMinjmum Reservoir Level
| Maximum Reservoir Level
Table 3.7 
Optimisation Rese1rvoi  600r and
Power Plant Charac
1.600
teristics
1.600
.
1.605
1.610
1.615
__W
7.8
8.2
J /s)
10 8
120
130
120
_B7
120
(MW)
J0.2
-
12.2
122
i Diversion No. 2 Head (m) _ ___________
180
Diversion No. 2 Capacity (MW)__________
Average Regulated Discharge I m 's±
Max Power Discharge (m
Diversion No_1 Head (mj
Diversion No. 1 Capacity
Diversion No. 3 HeadI (m;______ Diversion No 3 Capacity (AfW)
180 '
180
153
________ 184
19.3
-
200’ 17 4
________200 ________ 21.0
200
’ 22.0
The cost estimate for each of these projects  was  prepared in accordance with the methodology established in Annex  1G, 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 tnto 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
1,0% for transmission hues
Revenues  from  the  sales  of  firm  energy  were  estimated  at  the  rate  of  USS  0  07,  kWh  (January 1996)
For purpose of hj
t
s xnalvsis the three power plants were built to meet the expected P®weJ’^^n
of the Baro Basin The first power station would come on line in 2005. the secon in- lhe third in 2019.
___   _________________________ ____________ __ __— o River Basin Integrated Development Master Plan
Chapter 3Table 3.8
Project Optimization • Cost Estimate (USS *000)
Pnce Level: January 1996
Max. Nor. Res. Level
El. 1,805     EL 1.610
El. 1,615
Div. No.1 Inst Cap
10.2 MW
12.2 MW
12.9 MW
Div No.2 Inst Cap
15.3 MW
18.4 MW
19.3 MW
Div. No.3 Inst Cap
17.4 MW
21.0 MW
22.0 MW
Preliminary
1 729
2,124
2,557
Main Dam
8 448
11 081
13963
Access Road
400
40C
40C
Dwerston Tunnel
1.920
1,920
1 920
SptiNvay
545
545
545
Low level Outlet
216              216                 216
Subtotal 13.259
Power Plant A Conveyance
Diversion No. 1
16^87            19,601
Preliminary
1 296
1,450
1.504
Access Road
776
776
776
Powr Intake
0
0
0
Power Canal
1 605
1 605
1 605
Power Tunnel
0
0
0
Sirge Shaft
0
0
0
Pressure Shaft
0
0
0
Penstock A Marvfoto
1,000
1 000
1 000
Powerhouse A Equipment
5 253
6 283
6643
Subtotal 9.929
Diversion No. 2
11,113           11,527
Subtotal 12,649
Diversion No. 3
14.268             14.765
Subtotal 20.633               22,770           23.792
Transmission System
Preliminary
813
824
827
Switchyard Drv No1
550
550
550
Switchyard Drv No2
550
560
591
Switchyard Dry No3
’ 568
611
625
T ransmsi4on Une
3 750
3750
3.750
Subtotal 6.231
6,315             6,343
Physca: Conbngencxs (20%)
Engineering A Admmistratxxi [107.)
12790
7.674
14446
6,668
15,643
9386
if flVOLUME V
Based an the«
Table 3 9 assumptions, the 1RR of the three selected
schemes were computed as shown on
Table 3.9 Project Optimisation - Internal Rate of Return I6Q5_                    1610
Di versicn_No_JJ5?l—
BTverskulN^-3
Total ConstrucrionCostJLSS mJ) —
-,T
Annual O&M Cost (USSmii)-----------------------|
"Finn F.ncrg}jGWH/yiJi_---------------------------- . ' Annuai_ReYenuc_i USS_mil)_--------------- L
10.2
15.3
17 4
84.4
l 06
12.2
IRR i'%j
15.78
11 0%
_ 114
21 0
95.3
___1_24
271
18.95 11 4%
1615           ___ _J29________
19 3______ 22 0________
103 2_______ ___ I 3j _
2S5
19,94 ____ 11.0%
On that basts, 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 MW
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.l,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 b\ a separate, in-line diversion of the Gumero River.
Positive impacti
The subsequent section discusses the potential non-hydroclectric benefits of hydropower
The flood surcharge volume of the reserv oir is 300 mcm in addition to its active operafl 11° mCrn Flood attefiuation will undoubtedly occur as a result of normal reservoir
review o'? h * °
I  Wever
» fl°od control is not the primary purpose of the reservoir, and based on the
‘be Ofa 50,000 map, it appears there is practically no settlement on the Gumero and
nvers downstream of the dam site
fisheries-^either the studv by Seikhozpromexport nor ARDCO-GEOSERV provides th ” ‘he AbTXCS f°r ,mP°undments in the upper basin Seikhozpromexport (1988) estimated
° reservoir in the lower basin could produce an annual catch of 100 t for its
1A
___________  __________
Akobo Rtv*r Biiiin Integrated DeMtoptnent Master Plan
Chapter 3prefeasibility studies
v olum v
£
2
2,210    hectares    reservoir.    This    result    cannol    be    extrapolated    to    upland    reservoirs,    ho^? without further study.
Fuelwood, .Among the mitigations recommended by this assessment is the total clears^, biodegradable material from the reservoir area The woody biomass of the dam and reservoir si'
has not been surveyed other than in the context of the 1995 Woody Biomass Survey by The^
Using his results, the reservoir lies in an area whose potential dry- woody biomass lies betw
30  and  50  t/ha  For  the  area  of  the  reservoir  (30.9  km ),  this  translates  into  a  potential  fuelwooj supply  of  between  92.700  and  154,500  tonnes.  At  5  Bin  per  20  kg  bundle  of  fuelwood,  its  pos" resale  value,  exclusive  of  the  cost  of  collection  and  preparation,  is  between  23  and  39  miLlion  Bl- (USS 3 .7 and 6 1 million).
Recession agriculture and grazing The reservoir offers  the potential for recession grazing i-.d agriculture during the dry  season Poorly  drained areas  have been traditionally  used for dryland graztng 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,   shoreline are  likely  to  be  broad  and  undulaung,  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
Aejfan ve environmental impacts attd their mitigations
Large dam projects  cause irreversible environmental changes  over a wide geographic  area am 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 WTiile there are direct environment 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 soils, vegetation, wildlife and wildlands, fisheries, climate, and human population in the area The dam’s  indirect effects  include those associated with the building and maintenance of the darn 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 historic or other features. Loss of wildlife habitat,
■    Proliferation of aquatic weeds, Deterioration of water quality,
' Reservoir sedimentation.
Riverine fisheries. Water-related diseases.
TAMS-ULG Bi.ro-A kobo River Bttlri Injqjmiwi Devefopiocnt MBiicrTiaT
35
Chap«r 5pREFE ASlBILm STL OIKS
VOLUME V
. Conflicting demands for water, and
. Increased land pressure
Constructive Construction camps usually comprise quarters for between 200 and 600 men,
contain showers, cooking facilities, toilets, generators, fuel dumps, cement machines, parking
^eas - 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 their 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 primary  sewage treatment is required, otherwise, extensive septic systems might be permissible
The construction of the Gumero Dam requires 10 km of road improvement Roads have een shown to be an important contributor to soil erosion, primarily because they concentrate and
■stnbute runoff as channel flow rather than as uniform overland or subsurface flow.
Acc«s roads  will be constructed to a high physical standard (compaction, gradient, surface be usri ftn °rder t0 accommodale lh« weight of heavy  equipment As  these roads  are likely  to safely  °r years foll°wing dam construction, the major structures  should be designed to roads 'J*e 25'Vear Sood and the minor structure to safely  pass  the 10-year flood Temporary comniot; constructed to a permanent standard if their use will continue following
mpl",o"«f'l>edMor«herstnXe
^ploitatiorr^  ®
e
ec tive means of access to inaccessible areas, they open areas to increased
°8&ng. farming, hunting Hifch standard roadways should avoid intercepting
^MS-ULg ”—------------- -________________________
River Basin Integrated Development Master Plan
36
Chapter 3PREFEASIBILITY STUDIES
VL
° VMty
primitive areas, national parks, controlled hunting areas and locations of exceptional hjstQri
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 engm^
design Longitudinal drainage is likely to require a raised bed and ditches Cross drainage sfoS
follow existing channels and be designed to accommodate debris as well as water and seriim,^'
Culvert outflows should be constructed to a level below the stream bottom so as not to interf
with the passage of aquatic life Culverts on steep slopes may require an energy- dissipator befo^
they discharge onto unprotected land A Soil Erosion Control Plan should be des eloped durin
the project design and precede the onset of construction Its purpose is to provide guidelines far
controlling soil erosion, sedimentation and pollution
The Soil Erosion Control Plan describes  the location and type of controls  to be implemented 1; 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  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 die 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 wu established
Retain sediment on the site. This  principle is  achieved by  using devices  that filter sediment from runoff or that detain runoff so that heavy  particles  will settle. It includes  the use ot 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. Diverse berms and channels might be required to divert clean runoff around the site
j)qm and appurtenant works
Because much of the required fill will come from the reservoir impoundment area, its impact up°r the environment is encapsulated within that of the reservoir The demand for rockfill (neart)
0 5 MCM) require quarries outside the reservoir area Quarry side slopes should be gTaded w gentle gradient prior to their decommissioning, the quarry floor should be sloping towards back cut so that runoff and sediment are impounded Prior to the rainy season, the clliar? entrance should be partially closed with a berm in order to retain runoff Upon decommission’* - the quarry should be graded to drain in order to reduce the habitat for mosquitos.
With regard to diversion works, spoil from tunnel borings should be removed to a protected s’* isolated from streams, rivers, and the reservoir
Dislpcqnon of people The study by ARDCO-GEOSERV (1995) shows that 7 households be dislocated by the Gumero reservoir. The World Bank resettlement criteria for disloca*
1
TAMS VLG B«n>Akobo River Basin Integrated Development Master PlanPREFEASIBILITY STUDIES
VOLUME V
_|e should be followed The farmer gross margins for the reservoir area is estimated to be 250
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 CSS 620 per household or USS 4,340 for the 7 households
lu^ofjgnd The reservoir will impound 30 9 km 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)
[ lliS  of historic. cultural or aesthetic features These components were not assessed at this level o5tudy but remain for feasibility investigations
/ oss of wildlife habitat The Gumero reservoir will occupy less than 5 percent of Selc 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 reservoir upon wildlands and wildlife habitat is  not assessed at this  time It is  a subject that will require attention during feasibility studies
Proliferation 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
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 the residence time of the water in the reservoir From a totally empirical assessment of the Gumero 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 jodegradable biomass In addition, a multilevel outlet should be considered to release water from different levels
^ piQtr sfd^nfatinn The reservoir will likely accumulate coarse sediments at its inlet and
mlets along its flanks Fine sediments may develop into density currents that will carry 
a«umu|S ‘ dam faC€' whcre thcy ** flushed ,hrou8h lhe low level "‘d'1 Sediment
4 sedimenIOn *" reservoir is estimated to be 516,000 cubic metres per year Prior to design
Jive stora™ measurerTierit campaign should be undertaken to confirm the estimate The reservoir
8e 15 des'gned to accommodate a minimum of 50 years of sedimentation
Messed^he    reservoir    may    interrupt    fish    migrations,    but    this    has    not    been    directly Considered thC C0Une of thls or previous studies A fish ladder and hatchery' should be
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33PREFEA SIBIlTH STUDIES
VOLUMt
v
Water-related diseases At this level of prefeasibility study an assessment of the
reservoir with regard to water-related diseases is speculative, only some indications can be d,’1 from cutside the project area and, indeed, from outside Ethiopia.
The risk of malaria and other diseases related to mosquitoes, gnats, midges, and other carriers that breed or depend upon water (yellow fever, dengue, Onchocerciasis ) will chan
from beina seasonal to becoming perennial The increase will result from improved breedin 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
Anti-malarial programs using pesticides such as DDT pose their own set of hazards and coj^ and are not recommended given that many of these substances are banned Similariy 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 reservoir is, :«■ 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 the risk
u'
Schistosomiasis  does  not  present  the  same  risk  for  hydroelectric  reservoirs  as  it  does  for  irrieaiitr which   brings   man   into   intimate   contact   with   water   At   Gumero,   the   potential   for   infection   is unknown   given   that   we   have   no   information   about   the   presence   of   Btomphalana   or   Buhms Infection  would  affect  people  who  used  the  reservoir  for  recreation  or  as  a  source  of  domestic water.  The  greatesl  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  short area,  coupled  with  training  in  hygiene  and  health  If  the  reservoir  were  intended  to  supply  wa«r to nearby households, then water stations removed from the perimeter offer another response
Trypanosomiasis does net appear to be known high in the upland watersheds, but informant about this disease is fragmentary and inconsistent Selkhozpromexport (1988) reported « 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 proximo to the site.
SdkbozprDmexport (1988) reported the absence of the mosquito earners of Leishmaniasis in ti* krAtr basin There is no information about their presence in the vicinity of Gumero reservoir 01 indeed. their continued absence in rhe 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 betwee man, soil, and water as does irrigation
Corrfbctins- demands for water Provisional minimal continuous releases from the Gumero
and its in-line diversions are computed at 8 percent of mean annual discharge or 0-70 111 ;S. Feasibility studies will be required to evaluate the effectiveness of this discharge to sustain P  *”
re
populations of water organisms and competing water users The present study has not b f provided with sufficient data to compute a flow duration curve based on mean daily dischnty from which minimal flow requirements are usually estimated
The river segments most at risk occur between the dam and its furthest power station 1 scheme envisions 3 diversions, the first 8 km downstream of the dam, the second 12 km 1 ’ TAMS-CLG Barti-Akabo River Bub Integrated Dei dopment Master Plan
39
‘chip“’r 3^feasibility studies
VOLUME V
third 25 km Each d'version take* wat" thc
River to feed into a power canal The
Xed reaches have respect.ve lengths of 3.2 .5 and 6 km The maps of these diversions and their corresponding canals show no dwellings or roads in their vicinity We conclude, therefore thai the risk of conflict is low, subject to the findings of the feasibility study.
lncreased Ignd^resspre The Gumero reservoir will require the relocation of 7 households -Trrentlv resident in its 30.9 knT basin The development is unlikely to attract an influx of people ^to (he area other than for the dam construction
j < The Recommended Project
J. 5.1 Project Description
The Gumero Project storage dam is located at the downstream end of a marshy 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 tops above the potential high pool level Al the site the drainage area is 443 km" At high pool, elevation 1610, the reservoir has a surface area of 37 km? and at minimum pool, elevation 1600, the waler area is about 13 km! The dam is 35 metres  high above the river 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 the maximum surcharge will be 2 m Downstream of the crest, 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 runnel and outlet 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 divert river flows  into the tunnel during dam construction, is of 10 metres maximum height The gated intake structure and tower "’ill 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
er ®on. Forpowcr operation, the service gates will be closed when changing the opening of
tun | .CtlVe withdrawaJ gates so the latter can always be operated under balanced pressure The
J* discharges into the spillway outlet channel, excavated in rock at this point, so that a stilling
® "o’ expected to be required
m  ™£°Wer   divers>on  is  located  9  kilometres  downstream  of  the  dam  The  diversion  weir  is be  built  rn  COncrete.OS*  action,  12  metres  long  On  the  right  bank  a  canal  intake  structure  will for 13                    with 2-2x3 m sluice gates Downstream of the intake structure, the canal, sized depth  it    "the   peak    P°wer    Ao*,  will  generally  have  a  7  metre  bottom  width  and  a  2  metre
wide acc J 
lhat il be mostly excavated in rock and will be concrete-lined 3-metre
len gth of 26^ majntenance roads will be provided on both banks The canal will have a total metres When more is known about the topography and condition of the rock, it
---------- ________ ________________________ _____________
lr ^Akobo River
ln(egr ted Dcvc O
,
|
pment MwterPlw
40
Chiptcr 3PREFEASIBILITY STUDIES
VOLUy^- y
may prove advantageous to size the canal for the mean daily power flow and provide
regulating reservoir at the head of the penstock 
rc '
The penstock 15 2.0 metres in diameter and 400 metres long to develop a total head of 120 metre
The maximum plate thickness is 13 mm At the powerhouse the penstock will bifurcate to sun?
2 - 6.1 MW turbine-generators, each turbine will be equipped with one 1 00-metre diameter in]
valve, and will have a runner discharge diameter of 0.82 metre The turbine-generator sets <
run at a rotational speed of 750 rpm
The powerhouse will include two generating bays and a service bay and will be 18 metres long
and 9 metres wade, and the bottom of the draft tube will be approximately 6 metres below ihc
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. 1 local
load and 1 bus tie) approximately 12 metres wide by 75 metres iong for a total area of 72 metres 
by 75 metres. One line will be connected to the upgraded Gore-Gatnbela transmission line and
the other will be connected to Gumero 2 switchyard The existing 66 kV line will be sufficient
to carry the load from Gumero to Gambela when only Diversion No. 1 is operating As the othe
plants, Gumero 2 and 3, come on line, the existing transmission will require upgrade or
replacement to carry the load in excess of 50 MW For that purpose the connection between
power plants is 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 the 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 10 develop a total head of 180 metres  The maximum plate thickness  for this  penstock  is  15 mm
At the powerhouse the 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 Q metres wide The turbine will be provided 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 krr- from the dam The diversion weir, the intake and the canal cross-section would all be similar Diversion 1, with appropriate modifications due to differences in topography and geology power canal would be 6000 metres long leading to a penstock 2.0 metres in diameter and metres long to develop a total head of 205 metres The maximum plate thickness for
penstock is 16 mm At the powerhouse the penstock will bifurcate to sen e 2 - 10 5 MW UItl in the powerhouse.
The powerhouse overall dimension will be 17 metres long by 8 metres wide including generating bays and one service bay The turbines will be provided with an upstream vaJve , metre in diameter, and a runner having a 0.75 metre discharge diameter The unit is at a sp
TAMS-ULG Baro-Akobo Rhcr Basin Integrated Development Matter Plan
41
Cli*PKr3^t*s®B-nYSTC1’n:S
VOLUME V
Tbemyitcbyardwillconaaof5bays(2ilniu,nMi||
oal oldlndl|Mistf
|
rf "^Jamensto of 60 metres by 75 metres The projea connraa|
*
Gumer0 “
orofiles and sections have been developed in sufficient detail (see Drawings GL’-l to
to obtain quantities appropriate to the prefeasibility level In addition to major cost
such as excavation, concrete and eanhfill, quantities have been computed for such items e ‘^ ork. reinforcing steel, drilling and grouting, rock anchors, gates and other items
rices used to develop the detailed cost estimate are shown on Table 3 10 These were u "1' from bids for a similar project subjected to international competitive bidding m Africa and Sb. America and adjusted to a common January 1996 price level
Table 3.10 Unit Prices (January 1996)
w
Item
Unit
Unit Price
Common Excavation
m-
ra
362
Rock Excavation
m’
904
Portal Excavation
m
6 78
Tunnel Excavation
nf
50 84
Borrow Excavation - Common
m’
3 39
Borrow Excavation - Rock
nr
480
Mass Concrete
nr
90 39
Structural Concrete
nr
129 94
Concrete lining (tunnel )
--------- j------- m
203 38
Formwork
m2
50.85
Ste^Reinforcement
T
1,242.90
Unprocessed Fill I placement )
J nr
2.26
_?iocessed FiUjplaceinentI
m1
678
IfJt en
--------
m3
16.95
•^ELTransitions
nf
11.30
l^^ious Core
5.65
m
7909
-^Mlopenspace) ^Toutin
g                  ——-______
m
56 50
T
564 96
T
6,779
tn2
28 25
~-~~^fe!lLArches and Ribs___________________
T
2.260
Cost
estimate is presented in Appendix 3-1 and summarised in Table 3 11.
_______________________ ____________ 'er Basin Integrated Development Master Pl<n
42
Chapter 3PREFEASIBIl.m STUDIES
VOLU^fj. y
Table 3.11 Gumero Hydroelectric Project Cost Estimate (USS - January 199^
Dim & Appurtenant Works
Civil Works
21,780.000
Equipment
260.000 -----------------------------
Power Plant and Waterways, No 1
■
Civil Works
6,530,000
Equipment
6.880.000
Power Plant and Waterways, No 2
Civil Works
5,850.000
Equipment
9,000.000
Power Plant and Waterways, No. 3
Civil Works
11,010,000
Equipment
9,860,000
Transmission Lines
4,420,000
Subtotal
75,590,000
Contingencies (20%)
15,120,000
Ena & Adm (10%)
9.070,000
Total Construction Cost
99,780,000
J. 5.3 Implementation Schedu le
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 sun  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, availability  of  transmission  facilities,  it  might  be  decided  to  build  the  Gumero  storage  project,  tw< only   the   first   Gumero   diversion   initially,   with   a   consequent   reduction   in   the   initial   capi< 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    an powerhouse  would  require  2'A  to  3  years,  if  only  because  of  lead  time  required  for  the  out
gates,  penstock  and  powerhouse  electro-mechanical  equipment.  Thus  it  may  be  envisioned  1
first   power   from   this   project   could   be   available   about   6   years   after   commencement   of feasibility studies, or about January 2005 assuming start of feasibility studies in January l"9
Figure 3 4 shows  the anticipated construction schedule assuming the project is  implemented a continuous  operation, Le., that the full capacity  of the scheme is  developed at once For t scenario it is  anticipated that the power plants  will come on line at approximately  one y intervals, for an overall construction period of eight years
Alternatively,  the  second  and  third  diversions  could  be  delayed,  as  previously  suggested,  to the regional power demand. With the first power plant commissioned in 2005, the second wo
TAMS-ULG Baro-Akobo Rher Baibi Integrated Doelopnent Matter Plan
49
Chapter J^FEASIBILITY STUDIES
.______________________________ _ 
««»«« «™ m‘ "",hW m 201’ Figure 3 5 
VOLUME V
-------- -
rrwpated *ra»rf
!dWule »«uH wo ,he
Ec«nom'  *PP *
cr
iMl
lKa
^Guwero0thpecoJ -r^oqjehct will be supplying electric power within the Baro-Akobo basn and will be an
njn'-e‘
o f isolated diesel generators 
of this prefeasibility study’, the recommended project has been evaluated in terms F°r   **  ^of  generated  firm  energy  It  is  estimated  that  small  diesel  plants  generate  energy  at
o f unit c          Qi
^maintenance. uic
Based on the discounted costs of construction and operation and
-osts and operation <mu
* ^ ° . the Gumero project will generate energy at a cost of USS 0 049 per kWh
value analysis of the project was also performed taking into account the construction
ApreS£
.  nation  and  maintenance  costs  For  the  scenario  where  the  three  diversions  are
...
I ented at the same time as the dam over a five-year construction period, the economic 
- terral rate of return (EIRR) is 14 3% When the construction of Diversion 2 is delayed and not
tcoollm1m%issioned until 2012 and similarly Diversion 3 is delayed to year 2018. the EIRR is lowered
44FIGURE 3.4
GUMERO HYDROELECTRIC PROJECT CONSTRUCTION SCHEDULE
*        1      *IS1
«T
4Peak Power Demand (MW)
LI I ! [ U
------------------------------- L
2005                     2010                   2015                   2020                   2025 Yair
Gumero Hydroelectric Project
Implementation to Meet the Local Dementi
Figure 3.5prefeasibility studies
VOl-UM£V
4.          HANG IRRIGATION PROJECT
4.1 Introduction
4.1.1 Project Area
The Itang Irrigation Project called Itang-Lare in the Russian Master Plan, is  located some 30 lc west of Gambela on the right bank, north of the Baro River, between approximate elevations  4|< and 430 metres  above sea level, and approximately  between co-ordinates  33°57'E - 34°2l’E an- 8°09'N-8*27’N 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 oi Drawing No IT-1
The project area is  a flat plain Its  average slope is  about 0 0005 Most of the area is  covered tn open woodland, grassland, including mostly  bushes  and shrubs  The area is  limited by  the Ban? River to the south, some hilly  areas  with elevation of up to 500 m to the north, the Jikawo Rr.e to the north, flat flood prone areas  to the west and mild sloping terrain with some localised rod outcrops with peaks exceeding 500 m elevation to the east The lower (southern) part of the ara
along  the  Baro  River  banks  is  subject  to  flooding  Flood  water  levels  elevations  along  the  Bars vary from 415 m in its lower (western) extremity and 429 m in its upper (eastern) extremity
The area is  traversed by  the Gambela-Kurgen road This  is  an all-weather road. The road is<° be upgraded and extended to Jikawo A short, approximately  5 km- long, spur links  this  road to Itang
The   only   town   in   the   project   area   is   Itang,   the   population   of   which   is   estimated   at   23^ Population on the Itang and Jikawo weredas and on the Gambela wereda are estimated at 22, -*■
43,685  and  30.115.  respectively  Population  growth  in  the  area  from  1984  to  1993  is 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 ^hen power transmission line is the 66 kV Sor-Gambela-Dembidolo line served by the 5 • hydropower plant. EELPA is studying the possibility of linking this line to its interconn system
Small scale flood recession agriculture is practised along the banks of the Baro River vicinity of the project area In the region at large, livestock is a major economic activity dry farming is also present upstream in Gambela
TaMS-VLG Baro-A kobo River Basin Integrated Development Master Plan
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45E fFAS®lLnV STUDIES
VOLUME V
* i irfrv of Water Resources is the national institution responsible for large scale irrigation rhe Min nd for countrywide water policy, development and management The Ministry of
project an
^culture has nauu
to
; n-wide responsibility for agriculture
morial and local levels, the regional and local bureaux bear responsibility for day-to-day ^getnent and implementation of water and agriculture policies, development and services
Specific large
responsibility
project   development,   such   as   on   the   ongoing   Alwero   irrigation   project,   is 
the
of an ad hoc project office
Baro-Akobo Master Plan has analysed the present institutional setting and made several
nosals for the development of the Baro-Akobo River Basin One of them is the creation of
F River Basin authority- Details on the analysis made and the proposed measures are given in the
Master Plan report and in its Institutional Support .Annex 3G
4.2. Basic Data
4.2.1 Topography
Various topographic data are available in the project area This includes the following:
Maps at 1/50,000 scale with contour intervals every 10 m and interpolations every- 5 m
These include the following maps: Itarg, Lare, Jikawo. Birhane Selam and Shenkwar
Mountain for the irrigable area and hang and Sefera Tabiya for the hang 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 1/10,000 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 Sclkhozpromexport in 1988-89
A topographic map of the hang dam area of 1/10,000 scale with contours every 2.5 m and
■nterpolations every 1 25 m The available map is a reduction at 1/5,000 scale and covers 
approximate surface area of 5.5 km x 2 4 km or 13 75 sq km This map was prepared
y Stlkhozpromexpon in 1988-89.
4 ‘2 '2 Climatic Data
Ge -’*ral
^iuiia.^jjj£; J
Sl, nshine ev  1S availab!e for rainfall temperature wind velocities, relative humidity, hours  of
Meteoroloei 2T
(
10 extent
anSpiratl0ri          “d       evaporation       The       source       of       this       data       is       the       National ‘^ency fNMSA) Data was obtained through the previous studies and
b Te«ly fi-oni the
r Bajin Integra ltd Develcspniunt Mister Plan
-------------------------  ---------- ------ if-
Chapter 4PREFEASIBILITY STUDIES
Climatic Classification
The project area, according to the climatic zones of Ethiopia classification by the N
Meteorological Services Agency, is located in the Tropical Climate II (AW) climatic zone^n^
zone is defined as an area with a mean annual rainfall between 680 mm and 2000 mni
temperature of the coldest month is greater than 18’ C
Existing Climatic Stations
The only  climatic  station in the project area is  located at ltang. Stations  in the vicinity  of the project area, in the Gambela Plain, include Pokwo. Jikawo and Gambela. all located within aboc 30 km distance. Elevations  at these -1 stations, in metres  above sea level, are 415, 425, 4io anj 440, respectively Abobo, located about 70 km south of the project area is at elevation 455 mas[
Rainfall
Monthly  rainfall  records  in  and  near  the  project  area,  during  the  period  of  1952  through  1992,  are as follows
ltang 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 213
months
Jikawo 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  series  were  produced,  including  a  34-year  senes (1956-89) for all 4 stations
The resulting long-term mean values, in mm per month, arc given in Table 4 1, below
Table 4.1 Long-term Rainfall (mm)
Station
Jan
Feb
Mar
Apr
M*y
Jwx
J*
Attfi
Sept
Ort
Nov D»
5 lttni(I)
I0
5.7
123
47 4
137 0
100 8
1 172.7
134,4
105.0
] 10*0
59 5 _
01
6 Pokw-. (|)
4 8
245
468
116,7
124 7
' 1701
215 1
1543
122 6
42 8
4(
8 JiLano (2)
4.0
2.6
40.0
127 2
91.0
159 6
170.7
1220
67.0
4.0 __
2*
4 Gaflibda 11)
32
4.5
26.5
1 49.9
140.3
1484
215 9
194 9
1644
94 5
30.1
95
4 Gart)bch 13)
6.6
10.2
332
709
154.5
169,8
229 0
248 6
179 1
113.0
47___ _
Rs
4 Gaiebel* (4)
0
2
12
31
124
124
145
166
112
61
ii9j
0
4 Gambela (5)
0
0
20
” 1
116
86
159
149
134
76
20
0
(t) 1956-19*9.(2) 1973-19W, CJ) HimmoJ diu. 19O6-198S; (4) tt*. iduUey. I906-1W; (S) SOHirltUxlily '956-1?*9
The above clearly  indicates  a rainy  period between May  and October and a dry' period betw^ November and April The resulting distribution during the dry  and wet seasons, as  defined ab0'e in percent of total amount, is given in Table 4,2, below
TAMS-lfLG B»ro-Akobo River B»iin Integrated Development Muter Plan
Chi*P<er J"1”
VOLUME V
4.2
Seasonal
% Distribution
Dn
Wet
'^1956-1989)
14
86
Jtgg—-
pok»o_.
Jib#o
jam^
n, rainfaJI van« considerably A companion for the above long-tem, penod is given ,T<MeA5. below
Table 4.3 Annual Rainfall Variation (mm)
"71956-1989>
12
88
'JG97T1989)
8
92
“ (1956-1989)
11
89
Itang
Pokwo
Jikawo                  Gambela
2504.0                        1405 6                      1092 3                     1514.0
885.1
1031.8
796.6                       Tl082 7
185.2                         6548
544 3                       642.7
Maxinnjffl
Average
Minimum
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
VlOyear           102
Temperature
Temperature data is available at Gambela (Station 4) and Itang (Station 5) at elevations 440 and 415 rasl, respectively
*nd 72 m te?pera,ures ^ve been observed during 123 months  at Gambela, 157 months  at Itang have been oh S J'kaw° ^unn8 the penod from 1973-75 to 1985-88 Maximum temperatures dunng 1973 ^98^ ?3 niOnths at Gambela during 1980-1988 and for 134 months at Itang
as discuss^ in th              months at Jikawo during 1975-1985 Existing gaps have been infilled
Produced duriL .V IaStCr P,an
Annex   A. After infilling these gaps, a synthetic record has been
1
Itai Peratures mV* MaSter Plan studies The resulting maxima and minima monthly and annual sm Care v
9  CTinTab|e4 4
—__________________ ______ —-
Chapter 4
er Basin Integrated Development Master Plan
48prefeaslbility studies
V °LUMev
Table 4.4 Average Maximum and Minimum Temperatures (°C)
i
*i
Feb        M*r      Apr           Ml?           Junr         Jwh           Aug
Oct        Nov
| Aver M«(J)                               403       40.8       404          36.0          326          323          32 4        325          34J          14.8       36 fi Aver. Mtft 0)                   164       l*.4       20.3       Jl.S          199           182          17,3         17 1        18 1          178         17.9        16$
Iuni i Su 5)
Aw Mix (2)
Aw Min (7)
A«r. Mi* (2)
Awr. Min (4)
36.9       3f3        383       38 1         34 9          335          327          32.1
19 3     2D. 5      20.8       21 0         17.9          17.0
16.8         17.0
312 34.6
17.7 20.2
349
33.3
1S5        117
| 3*6 37.9 38.1 38.3 34 7 32.6 314 30 4 31.3 333 33.7 34.6 ’
IS 2       193       19 1       216         21 1          21.1         21.1          21 I        22 0         21.7         204        17.6
<1> !98& ISM: (7) 1S73-1 MU. (Jl IS74-1988. (4> 1975-19BB
Wind
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
7.1
March
5,9
September
6.3
April
6.3
October
6,0
May
83
November                            5.4
June
5-4 _________ ____
December
7.4
The above show? a very homogeneous distribution throughout the 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  ar  12  00  noon  at  Gambela  during  13  years  fro111   !^74   10 1986
The mean monthly data, in %, arc given in Table 4.6, below.
TAMS-VLG BaroAkobo River Ruin lntexrated Development Malter PLm
45>
Cb*J>ter4VOLUME V
Table 4.6 Relative Humidity (%)
61.5
Julv
rio. 8
58.5
August
80.8
57.7
September
792
' 64 6
October
73.1                   '              |
76 9                                       November
66.9
78.5                                        December
63.1
T5i< avefage annual relative humidity observed during the above period ranged from 67 5% to
73 3%.
rfojfTJ of Swish we
The  hours  of  sunshine  have  been  measured  at  Gambela  during  the  13-year  period  from  1975  to ]9g7 The average monthly records, expressed in hours per day, are given in Table 4 7, below
Table 4.7 Hours of Sunshine Per Day
taiiarv
7.00
July
431
Februan
7.77                                         August
5 15
March                                         6.16
September
5.77
April
6.38                                         October
6 62
Mav
5 23                                        November
6 92
June
491                                          December
7.38
The  lowest  values  correspond  to  the  rainy  season.  The  average  annual  values  recorded  varied from 542 to 6 83
mean   monthly   and   total   annual   data   on   potential   evapotranspiration   (PET)   and   lake ^poration   (LE)   is   available   from   records   at   the   Gambela,   Pokwo   and   Jikawo   Stations   The
bdcw* U<
^ * mean monthly and mean annual values, expressed in mm are given in Table 4.8,
ln
Potential Evapotranspiration and Lake Evaporation (mm)
Feb       Mar      Apr          M«y
1
June
Jul)       Aug       Sept       Oct
[----- 11 J__________1 __
NO
n" 1
98
176        161            130            113          107          113          116
1 124
123        113            91             79.1         74.9         79.1      |  11.2          863
1561.0
1091-
JE
r>.
—__ — — -JL. .
172
966        120     1 n>              93.8          79.1          763          749           826          88.9
. —1*—   1,1 ’
134 113  | 109 107 118 127
109
763
149
152 ”       115           88            88            97             110
108
104
106           80 5          61.6         616          67.9         77            75 6
n- "------------------------------ -- ------- _ —-------- -—
•T Basin Integrated Development Maittr Plan
Cbipter 4PREFEASIBn.ITY STUDIES
V °LUM£V
4.2.3 Hydrology'
There are 2 hydrometric stations in the lower Baro River The closest one is  t It
a
Gambela station is the next closest station. The drainage areas at these stations are 24 6 km and 23,461 sq km respectively Data at Gambela is available since 1906. [n 6
time, records are available at Gambela from 1967 to 1993 and at Itang from 1974 to lOg^^1
Several gaps exist in the available flow records. These gaps have been infilled as deschh 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
'n
r
Feb
M*r         Apr
May
July
Awj           Sept           Ort
_____________
(JunbrU
Il rrZ’iF
man
80.5 215 6
528 42 2 6C 3
127 8 1130 136.3
1330
356 3
374 0
969 3
67 B 4
9(15.9
105? 1
2745.2
727 3
194ft 5
—
Nev
Th.
>—=—u
—-
293.9
J Bl 7.0
2426J
------ ------
767 0
13*5
373.7
Hili
12 il
lun t
m7s                     112
j MR
300.5
74,2         61.2 179 5      166.5
1$2 153 1
106 j 4JU.0
376.7
97&S
664 2 1779.0
902.8
2418.0
1039 7 775.3
2695.0 2076.5
313 5
812 5
159 4    Wl
427.0 IMS!
About 85% of the annual flow at Gambela and 83% of the annua] flow- at Itang occurs  during the flood season of May  10 October The remainder, 15% al Gambela and 17% at Itang. occurs during the low flow season from November to April. The lowest flow is in March
Annual   flow's   vary   considerably   The   maximum,   average   and   minimum   flows   recorded   arc   given in Table 4.10, below
Table 4.10 Annual Flow Variation
■
Max
Aver
Min
Ratio Mai/MlS
Gambela tl!
__ -
mcm/vT
15,780.0
12,016 0
7.470.0
2.11
m’/s
500 4
381.0
2369
Itang *
mcm/vr
15.8500
12.459 5
9 080.0
1.75____-^,
m’/s
502.6
395 1
2989
<” 1967-1993
121 1974-1993
A detailed analysis is found in .Annex IB of the Master Plan.
Flood flow's are discussed in Annex 1C of the Master Plan
Flood water levels were estimated in the Russian studies at the gauging stations ana a site locations Data at the project area and nearby upstream and downstream of the ar given in Tabic 4.11. below
TAMS-VLG Baro-Akobo River Baiin Integrated Development Muter Plan
SI
j r da#1,„n m snores
VOLUME V
fable 1
GamMaxi  belma um InstanIttananeg Dousam Wat  Sieter Level EItanlevat g Sitonatsi (onmasi)  Jikawo Station
Station
1
1
436.36
429 60
424 65
41038
436 03
429.50
424 52
410.32
43576               ,
429 30
42444
410.26
429.20
424 38
410 23
435 31
428 85
42425
410.15
435.14
428.70
424 18
410 11
12.4 Stdimenl Data
nded sediment data is scarce and unreliable A discussion is given in .Annex IF of the
Plan Report For the purpose of planning the reservoir operation studies performed for
this prefeasibility study, an average annual volume of 13,560,000 nr has been estimated to
accumulate in the reservoir.
425 Water Quality for Irrigation
Although data on water quality  for irrigation is  scarce, some data on water sampling and chemical mahies  are presented in the Russian Master Plan Report, Volume HI, Annex  1. Climatology  and Hydrology
This  includes  the  results  from  analyses  of  51  samples  taken  at  various  locations  within  the  Bare i^ver Basin during 1986-1988
■henumbeT  of  samples  taken,  and  for  which  chemical  analyses  were  reported,  include  4  samples -t tang, 13 at Gambela, 6 at Bonga and 1 at TAMS’ site
ater quality data for irrigation can be summarised as follows-
Residual sodium
< 1.25 m equiv/litre
Electrical conductivity 
< 0 20 mhos/cm
Sodium Adsorption Ratio
varies from 0 12 to 0.36.
^®sed on Electri
LsdA classify cat Conductiv’ty (EC) and Sodium Adsorption Ratio (SAR). according to the 15 follows*100 ^vers’de). the water quality for irrigation can be classified as CI -S1 This
Cl * Lo
Sl * Low
Hazard   £C< 250
(          mhos/cm)
Sodium (Alkali) Hazard (SAR<l0)
.
ted
uctio^ ^°r ’rr'gal’on’s excellent
’u,"       °P
n m cr
e d s antic     ate<  due t0 water    ua
'^ ' ' *p ^ 9 ^
’ R‘Ver Bajin Integrated Development Ma»ter Plan
52
Chapter 4prefeasibility studies
4.2.6 Land Resources
l   and   resources   were   assessed   in   the   current   Master   Plan   based   on   data   given   tn   rhe studies by Selkhozpromexport carried out in the 1980s and published in 1990.
In the Master Plan land suitability evaluation, part of the area was assessed as suitable and
of the area was assessed as moderately suitable for diversified crops It was also found
suitable or moderately suitable for rice
Soils in the area have been studied and mapped by the Russians at 1/250,000 scale Subsequent] a combined map of the entire basin grouping the Russian map for the Lower Basin and the ARDCO-GF.OSERV map on 1/200,000 scale for the Upper Basin was carried out in the Mastr Plan studies and presented al 1/1,000,000 scale (see Master Plan Volume 4) At this time the soil types were reviewed and grouped This resulted in less soils ty-pes than the original Russian classification
P e\io
r
U!
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                                                                                                              % of Project
Class
4         Distric    and    Chromic    Cambisols    weathered    and    often    shallow    with coarse topsoil
5           Entric   Vertisols   seasonally   waterlogged   generally   fertile   often   flooded in lower basin, risk of sodic conditions
9         Dvstric    and    Entric    Fluvisols,    variable    textures,    usually    deep.    Slight erosion hazard
10         Eutnc Gleyspls, seasonally waterlogged Low erosion hazard
1 1         Dvstric   and   Eutric   Plinthosols,   variable   textures,   usually   deep   Slight erosion hazard
For their soils survey, the Russians made a number of test pits and auger holes,
samples were taken from Lhe test pits at various depths and lesis were made in the ... The laboratory tests on the soils samples included moisture contents and grain size (gradations^ Data from 10 pils in and around the project area, including 50 samples, were found. Pits 
up to 2 in deep. About 50% of the pits and samples are located within the project area an remainder arc located in the vicinity of the project area No data on the auger holes was 0
The results of laboratory tests from test pit samples arc given on Tabic 4.12
A 1:250,000 scale soil suitability and land reclamation classification map prepared by the Ru**-1 is available It contains VI major classes and 3 sub-classes (a, b, c).
Area
27
59
11
1
2
In addition laboratory
TAMS-dG Baro-Alcnba River Basin Integrated Development Mnitcr EUnVOLUME V
-------------------------------
•ah according to the following classes
fh^15
Class1
Class H
Classic
Class
Class V
Class VI
Then wn classes >n
VI
c lass|t,ea a
Lands not requiring fundamental reclamation measures and special engineering works
® ds not requiring fundamental reclamation measures but with certain Stations 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
are II ID and V There are also small areas in Class I and in Class m the project arc m
^ClG ---------------------- - ---- _____------------------------------------------ - ° bt> River Bum intend De^lopment M^r Pl‘n
54
Chapter 4
-PREFEASIBILITY STUDIES
Table 4.12 Hang Irrigation Project
Sample Hygro- 1
No.           depth cm        moisture     ‘1-0.25        U.25-0.05         0.05-0.01         0.01-0.005
Soil Fraction - %, Size J c mm
n  io mm
1687       0-16                  3.73              2! 52          39.50               12 31 17-27               3 63              20 44          40.39                727
0.005-0 Ofit
38-48
936                   5.25               " 7.76                  3 49
70-80             6.04              20.47         22 S4
(5.9S             20.60         22.30               6 53                 6.27                  6.95
5 73
180-190           6.50              17.94          2949               3.67                 2 70                  11 52
0.92                  14.52
-
3735
;
ii
1585       0-20                  9 20           . 3.70            4.40                 4.80                 970
30-40                1090          ' 2.S0            1 40                 350
30 80
-—------*
80-90 140-150
970 12 60
2 90
1 50
10 80 i-i1mj
100
690
t un
l.jU
3.40
7.50 ~J3 90 ~"
4 10                  10.40
J 74 6
64.SC ■;
190-200 I          12.70        1 2.50
10.60 180
1569       0-22                 6.60              4.30           21.80               11 CO             3.10              i 14 40 "
10.90
11.80 _
25-35               6.30              3 60           18.20               1340               2 20
50-60               8.00              3 80            1300              9.30
i iTso
70-80
5.80             V 12 70
110-120          7 80              260            12.00               12.50              4 40
8.00           I 2 .80           18 70               14.50              0.60                  16.00
74.70   j ?9.5O^?
4900 55 30 ■ 47 4{j ■
! 170-180            7 10              4 10           9.00
8.70                    59.80 S
10.90              4.60
12.40
1572       0-29                 4.00           | 8-60            20.00               11 50               18.80              8 90
35-45               6.00              7.80           12.60               7.20
10.30
19.10
70-80 620 1 6.50 23.60 0 70 880
100-110 640 4.70 13.90 11.00 5.30
15.90
58 90 ‘ ' 32 4G fl ] 43.00 ‘
44 50 f*
7.70                    5? SO i
150-160       [  8.80              4 10            1010              3.60
6.80                 10.30                  67 20 W
180-190           7.80           1 4.90           7.50                9 80                 4 60
1568       6-24                 6.61              391            13 58              7 4$ 24-49               9 17              3.95           1.95                0 83
'7.97
12.50
15.83
12.50               15.64
61 10 ’ll 51.13   ’3 65.14 \
49-90               9.17         i 2.77              6.34
1.57                3.01                 15.83                  70,48 j
90-123             10 25           2 49          6.01                 4 76
5.52                 1132                  69.80 h
123-70 170-200
1594       0-31
1074            2 88           0.96                835                  3.00                 12.17                 72.74. Ji
11.73           2 22           n oo                550
7.27                9 19                    71 82 J
12 00         1 200           0.90                 17 30              10.20              20.30                  49 40
40-50               13 60      . 1 M0             0.60                630                 400
17.90
70 10 l.T
80-90               12 60           1 60          6.20
5.60                4 50                9 10                    73 10 v
150-160           14 40            1280         20 80               18.60
1674    i 0-24                  2 88             11.63        43 86               11.60
45-55               4 70          1 8 60           26.32               13 70
95-105          1 4 38             9 ,12          3071               698
16 70              14.50                -16“ d
5.86 11.90
3.96                5 69
10.28
15 15
41 *! . .
33.90.
I
ISO-160          4.60              698           62.23               11.43              1234
, 1566       0-17
1.00             8.10          68.70               10.10              2 30
30-40               1.80          1 10 10        S« 30              3 30                290
9-41                L 25.64
280
830      ____ I
80-90
I 80          1 9-20          57.40              8 70                2 50                7.90
___
140-150          0.60              580         , 74.60              2 70
0.60                11.40
1682        0-16                8.34             7.21        ! 10 08              21 82              11.55             27.97
17.28. a oo . .4 17. li1 ;li 14.40 .. I
4 80
2ij7
25-36
7.53
9 13
1 16 49
26 47
8.20
24.74
J
50-60
L 6 72
j 5 79
2323
18.90
14.53
12 25
d!
7G-8O
6.20
! 5588
28 36
4.19
041
1 2.70
______
-7’
110-120
0.20
92.23
3.00
0.29
028
1 21
2??-
i
0-14
8.02
| 5.30
14.00
23 90
14.50
17 30
2500.- .
25-35
1 11,60
~l 4 70
n.4o
9.10
8 50
9.80
__J
66 40.
35-65
1 11.70
4 90
12 10
9.70
9.80
1 1 40
5^
100410
1060
4 50
3 10
10 10
8.70
10,80
.
J
170-180
12.70
2.30
1 130
14 90
7 70
6 JO
Source Sclkhozpromexpnn Mister Plan Report, 1990
TAMS-ULG Bsro-Akobe River Banin In learned Development Master PLua
■
Chap1**-4
- ‘-TTJVOLUME V
_______________________________________
p„ef 1'
rt on
;   covering approximate!} 8000 ha is a flat area difficult to drain” This area,
jht^ carefully studied, has been excluded from the fanning area and could either be purposes in the agncultural development or partly farmed if future studies 
forotnc 'L remaining area covers a gross surface area of 64,500 ha
.^ine50'
villages and other unusable areas, covenng approximately 5500 ha. have been U ^'^T|]e remaining gross area is estimated at 59,052 ha For the purpose of this report,
t 'C k called the usable area The net irrigable area, after deduction of the irrigation and
I* ** ”£ terns and related roads, has been taken at 90% of the usable area The net irrigable estimated at 53,147 ha, which is slightly in excess of the area anticipated at the
niBinng s»8 '
e
ll? Geology and Geotechnical
The Russians produced a geological map of the region at 1/250,000 scale. This Master Plan has -icxed a regional geology map at 1/1,000,000. There is no other geological map for the Itang
dun or the rest of the project area A geological cross section 08-12 was made by the Russians ilongthe iris of the proposed Itang dam. This section shows the site to be in lacustrine-alluvial posits 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 nd downstream of the dam site and at the 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 boles 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
5wie test pits were made by the Russians along the main canal, some distributaries and some
Ti>r  drains  OnJ v
.   a  brief  description  is  available  There  is  no  data  on  sampling  or  on  field  or
“oratory tests.
0 information on construction materials for embankments, riprap, and aggregates.
^JmXcti   IS    not    scismical|y   active   and   presents   a   low   seismic   risk.   However,   no   data in the vicinity of the project area is available.
of “ Pwsible in (he project area The climate. water and soil lend
u ding cereals, puli, oil crops, butts and vegetables, sugar cane fodder
Chapter 4
er Baiin integrated Development Muter PlanPREFEAStBILITY STUDIES
In order to develop agriculture, the lower areas need protection against flooding Ther • need for an adequate drainage system to prevent water logging in pan of the project T'sa,so
Vt >U'Mlv
* 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 mtenst is 166%
The crop distribution of this cropping pattern in percentage of the area, for the drv > a
seasons, is given in Table 4 13. below
yd*c
Table 4.13 Diversified Cropping Pattern
Crop
% Area
Dry Season
Wet Season
Cotton
25
----------------------- ——---- ---
15
15
Maize                                                                                                              40
Sorghum
19
10
Soy Bean
10
10
Vegetables
1
1
Fodder (green manure)
5
0
Groundnuts (peanuts)/oil crops                                                                       0                                           15
| Sub-total                                                                                                       100                                           66
Total Cropping Intensity
166%
1
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  may 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-industries, such as  oil extraction plants  from maize- soy  beans, cotton gin, soap plant from cotton seeds, peanut-based industries  Fodder urnuld be for feeding the livestock  Grain can also be used to develop poultry  farms, although grain mav 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 m several ways, such as to produce ethanol or as animal feed as pan of a mix Bagasse is also usable in various way-s
TAMS-ULG Baro-Akobo River Basin Integrated Development Master Plan
Ck»p>«r 4' m studies
VOLUME V
li!
, a of the total 53,147 net area would be planted in sugar cane while the 21 7ha may be developed for a diversified agriculture orientation as described
■ 0„ Water Requirements
requirements for the diversified cropping pattern were estimated in the
-■e  trnglt,on   wa'er    These  estimates  were  based  on  the  field  water  requirements  of  individual
‘ )jSler plan
^5 m the cropptHS
nern fOr both wet and dry seasons The net ungation water requirements the 80% reliability monthly (effective) rainfall from the field
fttrr determined by              questiori The gross monthly irrigation water requirements were
-t-jirements of «he
^ytsned by dividing^
inC u<  n
net water requirements by the overall irrigation efficiency The |  jj g field, distribution and conveyance efficiencies Table 4 14
^er was t^1^1
requ^enlents calculation for the diversified cropping pattern,
“(csccts th
.    .    Qiget    the    weighted    averages    for    gross    and    net    monthly    irrigation For   this   P*'CU"   P    red    the   mix   of   sugar   cane   and   the   diversified   cropping   pattern   The
awaits a%
of 40°/o p^gd in sugar cane and 32,147 ha or 60% planted in the
Overall irrigation efficiencies were taken at 50% for the diversified rotation
Ztor°the commercial sugar cane operauon The
described above for the diversified rotation, is presented in Table 4 15 and tn Figure 4.1.
“
58T»bl« 4.14 h.n
8 lrrig llon projec
.
, 
w>Kr Rciii).i emtn|j .Typlc„Cr((piitag pM(cni ||Jivm.ne<1)
I
I icld Waler Requirements
WEI SFASON
Cowon _25%
Miuzc 40%
Sorghum 19%
S , Ik HU 10%
Vegetables 1%
Circcn Manure 5%
Subtotal 10*3%
March I
Annual
87 5 45 1  125
128 40 12.0
19                 13.3       '
212 S
320 0
1
'5  1 80
08        1
7
QRY Sb ASQN
Cotton 15%
Maize 15%
. Sorghum 10%
Groundnuts 15%
Vegetables 1%
Sgy Bean 10%
Subtotal 66% 
•
~ 1
|
I i 1
_1 0
100
25
1 40
0
17.1
S
04
5
—
92 5
216 0
20
1 5
267 0II
121.1 L. 32 5
1
-- 1
)
16.5 I      28
165
9 9            22
66
0.4  | 0.7
57 8
731 1
140 3
41.3                 132.1
.      125 6
!                                55             16 5
17 6
23 1
I 2
22.0
p        l       0                  32 3            903                   1630                 190 6
57 2
85.9
3 6
71 5
Total  Crop  Intensity  166%
Held Water Requirements
1256
Nel Irrigation Requirements (2)
92 5             216 0         J_ 267.0
-mm
-----
-mVha
~125 6    ~ ~ ~ I
1 12S6
5
98 0
122.0 |         0
Gross Irrigation Requirements (3)
-- J
163 0
1630       |
1630
122! 7
655 3
6551
-m’/ha 
-1/s/ha 
2512
Q 94
; o 980 1220 0
1
-0-
J96O 2440 ”o 3260 11106
'      0 76
vSwm‘"rfa"' ?M)% rd'nb~ *’ tB’Cd aP‘’ *” ’
t ma,eJy »0 
,
Z)_ Hew waler icquucmenls minus eflccU vein infall
nxords at Gantbela Annual means total annual
—         —             —
3) r« 5Q%jmgntion efficiency, including held, distnbuuon am! convey amc losses uitd waste/ /?7Zcc?f/w KdiiiIiiH tn nifil ( IJ
/ l'tcld_Wtitct UcquuciTKiils -
/ Suxur Cfina - nun
I Nd Irrigflioii Requirements -
/ Sugar enne - mm
_o
i2O~
120
_ o        I----- =-----
——               il
too               1 18
1 IO
J IO
&
145
__i
too
iftG
IOO
tin
1 IO
1
120
too
«•
120
15
30
u
140
1
120         |’ 102             1 85                 0                 0
__ 9 VI____
\3OO
747
° 1
o1 1
O
65                MS                   140
/ Gruss W/ifcr Requirements - Sugar cane
I
i
j1
1
... 1
1
i
/ fin 6O4i efficiency
I Gross Requirements
1
I 200              200              170                j 142                    0                 0
o 1        0                0                   108                  192             233                      1245
1 Diversified Cropping                       1               I
1
1
1
for 50% efficiency (3)
Gross Requirements
Weighted Average
- mm (2)
- in Mia (2)
1/s/ha (2)Q
Peak - 1/s/ha (2)
I 251 2            1114            31 4             0                0          196           244 0                0
1
_.1
'1
0
0 1 I SO 6 3260 13106
1
i
1 11
230.7           146.8              86 8 1       56 8             0           117.6        146 4               0                0                      43.2          167.2      1 2888                  1284.3
1
2307          1468             868                 568                0           1176 0.86            0.61            0 32              022 |       0             0 45
1464                0         1 0
' 432              1672           2888                   12843
055               0
1____ —
1-
0
0 16          065
-L u 1
1 08
1
i
I) tor
reliability based long lerni iccord* at Oambcla Annual meant total amount
2)    Assume* 21000 ha wgw cans pin* ^2147 ha in diversified rotation
3)    Calculation fix divd«ified cropping pattern is given in Table 4 14HANG IRRIGATION PROJECT
/'HOSS MONTHLY IRRIGATION WATER REQUIREMENTS CANE («*) * DIVERSIFIED CROPPING (ftOX) Mu
MONTHSvoi.t Mr. v
•   «/j<* » —
«ir operations were simulated with the HEC-5 computer model The simulation
rfSi? mOnthly routing of a 64-year time senes Releases are made to meet monthly 
shown on Table 4 16. as well as the minimum environmental release of 51 nr’/s
T«bl« •‘-16 Monthly Irrigation Requirements (mJ/s per 10.000 hectares)
July  ~
August
. 5 50
J) 00
September
October
November December
jO 00
H 60
6_5O
fioso
Tk   reliability   cntenon   used   to   assess   the   imgation   potential   of   the   reservoir   was   selected   as fofows for each month at ieast 80% of the monthly water requirements are met 95% of the time
Biscd on the initial active storage in the reservoir shown on the Area-Capacity  Curve (Figure 4 2) cf IP 4 mem. the water releases  can be regulated to meet the imgation demand of the 53.147 heairts considered for this project, as well as the minimum environmental release
However, it is  anticipated that sedimentation of the Itang reservoir will significantly  reduce the Ktne storage .Although there is  no specific  and reliable data for the project, it is  estimated that «&nem accumulation in the reservoir could average 13 6 mcm per year This  could possibly 
•«u. tn a significantly reduced active storage after ten to fifteen years
rserv 
In
^ so s^oun that with the development of the hydroelectric project regulating
. uPPer basin, the need for active storage at the Itang dam becomes  less  and less 
Reas    indicated    in    Appendix    U    of    the    Master    Plan,    the    two    most    promising    hydropower
ftt pe«:vth rPPCT *> S
a
' n 316
Baro with installed capacity of 171 MW and 210 MW
very    good    rat    °n      the      cvalua,'on      performed    for    this    Master    Plan,    these    two    projects    have    a
*nhn 'he ncxt° ioCtUni
,
excclIent candidates to be integrated in the interconnected system
rt 8uUoon provided10 2° ycars' tbat basis, the reservoir operation studies evaluated the
:e gutatj
On WOu d
Pf *a
’ »Ppean  h
|  * bv tbc ,u° reservoirs, Geba-A and Baro This analysis shows that this 
the Itan dSUffiCiem 10 Irngate UP 10 l00.°°0 hectares at the Itang we without active
?    Thcrefore if after several years of development of the Itang Irrigation
have                  the rwervoir is losing part of its active storage, it is likely that upstream
**    rtservoir
deve,0P«d    and    it    would    be    sufficient    to    compensate    the    sedimentation    of
r ^'r,gatl°n ,nfr^tructurt
•'ll
iQfy
° u’ ^d a nr?|C,Ure c°mPnsing the Itang Dam and the imgation and dra
inage systems 
"runary design was prepared for command of the 53,14
ha net project
~ ____________
er
Integrated Dcvelopmeot .Master Plan
Chapter 4
61Elevation in meters
>-
Area in km2
Reservoir Capacity (mcm)PREFEASlB^m STUDIES
VOLUME V
area. In addition, a flood protection dike svstem
enable development of low lying flood prone areas draina®e
pumping scheme arc provided to
ItangDam and Reservoir
Itang Dam and Reborn would be the storage and river regulating structure for the Itang Irrigation Project The selected site, x5 fan downstream of Gambia and 10 km upstream of Itang strikes  a reasonable balance between length of dam, storage and relocations  The dam crest elevation is  limited by  flooding conditions  at Gambela and the resulting live storage, while adequate for initial operation, to be maintained will require preventive measures, such as  upstream storage, 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 over 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 m /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  m /s  intake  located  on  the  right  bank  of  the  Itang  Dam  and
a
would stretch along about 53 km. ensuring command of Lhe project area Its  design capacity' of 10.5 m7s  to 58 5 m7s  is  based on the estimated maximum monthly  irrigation water demand of 1 1 titres  per second per hectare for continuous  24-hour operation <see length profile on Drawing
TT-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,   lhe   gradients   will   range   from   0   00004   to   0.00005   and   lhe   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   ai   o       nCreased   rate    was were designed for a unit peak rate of 1 2 litres per second per hectare
adopted to add flexibility in their operation The gradients of the secon ary 0 0003 to 0.00! and the veloatiePs range from 0.4 m/s to 10 m/s The
design
Reifies    of    the    secondary'    system    range    from    1.6    n?/s    to    15.94    mJ/s.    Then    combmedHenins 73 ^ A roughness coefficient of 0.025 was used for the secondary
Aboard    used    was    0.3    m    The    secondary    canals    would    be    provided    with    a    service    road a Ppurtenani structures
SimMy. asurih dlajM
"«en secondan./coU^'aXl
b provided The system is famed by one man dram
8
Integrated Development Mailer Plan
62
Chapter 4____________________________ %
PRPREEFEFEAASSIIBBIILLmm S STTUUDDIIEESS
Voi
capacity   of   1.5   litres   per   second   per   hectare,   which   is   based   on   the   concept   of   dcwateii year return maximum 24-hour storm of 115 mm over a 9-day penod
The main drain was designed for a 0 0003 gradient, velocities ranging from 0.77 m/s to o q and 0 5 m freeboard The roughness coefficient used was 0.030. The main drain would k 1 km long
The secondary drains were designed for a 0,0005 gradient, velocities ranging from 0 4 rn/s m/s and a 0.5 m freeboard Roughness coefficients used were 0.030 for the longer drJ? exceeding 5 m /s capacity and 0 040 for the small drains with lower capacities The total
of secondary drains would be 79 7 km
Typical canal sections are given on Drawings IT-8 and IT-9
n8 a
3
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 this  typical sector, one for surface irrigation (Drawing IT-12) and one for sprinkler irrigation (Drawing IT-13). Although both systems  are feasible, the sizing aa cost estimate for prefeasibility  analysis  was  done for the surface irrigation scheme only  The purpose of this  study  was  to establish unit costs  per hectare of the tertiary  and quatemar. distribution and drainage systems  The net area was  estimated at 1.631 hectares  or 90 percent <x 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  Gradieas ranged from 0 0001 to 0 002, and velocities  ranged from 0 3 m/s  to 0.6 m/s  Freeboards  usee varied from 0 20 m to 0 30 m The system would be provided with service roads  and appurtenan 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 pe 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 io protect the flood pr°^ areas against river flooding and/or a combination of high river stages and a 24-hour storm ' a 20-year return frequency The layout resulted in 3 separate dikes for the uppermost, middle lower portions of the project area
The dike system would consist of low earth embankments with downstream rock protection a service road In order to dewater the protected area from heavy storms and from irng return flow's, 9 low-head pumping stations and a flap valve would be provided. The Pu stations would be equipped with electricity-driven vertical centrifugal pumps and as5^C’nVej electrical and mechanical equipment The pumps would discharge to the river at vans stages by means of pipes built through the embankments and flap valves
An electric power transmission system would also be part of this projecl The system,tO1^ of 33 kV and 13 kV lines, would supply the dam operating gates and the pumping static T A MS-U LG Baro-Akobo River Basin Integrated Development Master Plan
63[r[ASIBI
Lm STUDIES
Smales of Costs
VOLUME V
and Benefits
Croon#stmction costs were estimated generally a<:
w arcrRes0
f ^matw. given in the Master Plan
‘ SCLJSS^ jn
ne msin unit costs used, expressed in USS r u
Uan ,996). are give-. T
°5t
to addition a 15% allowance was estimated r instruction facilities 
5
"ofliMhon
“’Table4.17
r °r contractor-
Md ,eni
Pie   annual   operation   and   maintenance   costs   were   arrived   at   on   a   percent   of   construction   costs 
Toni construction costs were arrived at h
bias, as follows.
Description
%
m Porary ce for engineering
Civil Works
0.5
Mechanical & Electrical
3.0
Irrigation & Drainage
. 15
Transmission Lines
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 wd Financial Analysis, of the Master Plan More detail is  given in the Economic  .Analysis presented in Section 4.4 4
____________________________________________
ailn Integrated Development Master Plan
64
Chapter 4PREFEASIBILITY STUDIES
Table 4.17 Unit Costs (January 1996)
Item
a)             1 Irrigation Systems
Unit
—
1
Cleaning. Irrigation
Hectare
Stripping
m
6000
1 Sn i
Excavation, common, irrigation
m3
Compacted fill, main/second incl hauling
m'
----- — _ JjQ
——-JjjT
—----— _
Compacted fill, other
m3
5 6n
4 fin I
Concrete lining & formwork
m3
120 00
Wire mesh, welded
m3
1
—r-— 3 80
Roadway gravel
m'
25 00’'
Roadway base course
m
18 00 ~
Structures
%
10*4
b)
Dam
Road improvement
km
ZD 39 546 85
Excavation, common
m’
3 62 ’
Rock excavation
ms
904
Borrow excavation, common
m3
3.39
Borrow excavation, rock
L m?’
4.80
Unprocessed fill placement
m3
226
Processed fill placement
m3                                                      6.78
Hauling fill material (over 2 km)
m'/km
051
Impervious core material
nr
11 30
Fillers, drains, transitions
nr
16.95
Riprap, placement
m5
3
565 -—  —
I—
Mass concrete
rm
90.39
Structural concrete
1
129 94 _
Form work
m'
5OJ5_
Steel reinforcement
T
1.242 90
—
56.50J
-r— ------   — -                  — ■  -------- Drilling for grouting and drains
Drilling for drains
u
“
m
79 09
Anchors, incl drilling and grouting
m
T
14,91481 _
L                     Grouting
T
56496_
1                     Unmeasured items
%                                   5%___
4.4. The Recommended Project
4.4.1       Project Description
Itang Dam
Itang Dam will be of earthfill construction. 5500 metres long wnh a maximum heigm metres and its crest at elevation 436 0 .Although there is reportedly outcropping and spillway site, most of the length of the dam is expected to be founded on deep aliu' upstream impervious blanket will be provided for seepage control
TAMS-ULG B>ro-Akobo River Baiin lnUfraled Doek>pm«nl Master Plan
65
. H of ab°u* 14
Cb»Pter 4stldies
VOLUME V
j;0
f(lo ds^  ' f"'   ' P ' '   'hfceSxlo.
0
a, d    vay S   0 ld dM
mnr
n
SZ has the capacity to pass the (routed) “X I*
d in flu
J° * ^g
charge above normal maximum pool elevation of 43 ] 6
flood with
W?iS5ig - r2 approximately  nver bed level, and 7 mctresspillway  sill
;ifleffC5 SUf
,non intake is on the right bank and will be provided with ten 1y1 <
8 5 based °" wa,er lTOI
X
resent
n. „ ronstniction, the river will be diverted into a 100-m wide dku
na
Bendin the river The channel is designed for the 1:100 year Th^nhlhM
fcbuilt up to both sides of the channel and Lhe concrete spillway constructed « th
Tte river will then be diverted over the spillway and the remaining portion of X L'ntnt' Tk
,-jad in the diversion channel The spillway sill is so low thatifanv problem^
during reservoir filling, the spillway can easily serve as a low-level oud«
C'°P
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
An overall layout of the irrigation and drainage systems  and the flood protection dikes  and jumping stations  is  shown on Drawing IT-2 This  drawing also presents  the axis  of the dam and tie imgation intake location
The main canal will be approximately 53 km long The canal capacities will
c the OTigm at the intake on the nght bank at the Hang Dam and
s
sections are
fegth   prcfc   of   the   main   canal   is   presented   on   Drawing   IT-6   The   typical   cross   secttons   are shown m Drawings IT-8 and IT-9
Tne project will have 12 secondary canals with a
^parities at the ongin will range from I 8 m /s to 15 m 1
W as the main canal sections
„ indnde a B ‘combined length of about SO km
addition, gravity distributions and drainage sy layout of
.. h of 87 3 km Their maximum
3
. epical canal sections are the
covet the w
chyble area covering 53,347 net hectares Rented on Drawing IT-12. The on-farm layou
D ovC
‘he P r» \4.
r
1
„,m, and on-fe™ ’’’'"Lj gras* *sin"'
n on D‘*vrtn®
-
The syslcin
,
a
Kt »ood protection system is proposed for the Tow W8 ^em IS shown on
2** of three earth dikes A length profile of the
3 cal ctoss section is presented on Drawing H'
hood prone at Drawing TT* • 
A kobo Riv^ g T——_________________ -_____________ - Integrated Development Master Plan
66
Chapter 4✓
pREFFASIBILm STUDIES
V0L^.,
XS    10    Mca.es    their    location    along    the    dikes.    A    typtcal    section    is    presented    on
IT-11
4.4.2 Cost Estimates
A    construction    cost    estimate    was    prepared    for    the    proposed    project    scheme,    as    described    jn section 4.3,5, above
The estimate is presented in Table 4 18 A separate detailed cost estimate was prepared for liang 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
llang 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
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
Levelling
26.573,000
Clearing
6.378,000
Subtotal
302.873,000
Contingencies 20%
60,575,000
Engineering and Adm 10%
36,345,000
TOTAL
399,793,000
In addition, an estimate of annual costs  was  prepared for the project, This  includes  construcuoi costs, in accordance with a proposed project schedule given in section 4.4.3, and operation ar~ maintenance costs after construction The annual costs  for the period from 2001 to 2020 and thereafter, in US J (January 1996) are given in Table 4 19.
< 4 3 Implementation Schedule
A    proposed    implementation    schedule    was    prepared construction activities
This indicates both pre-construction
oroiea
“ IW“5 snid"s
"T™’ " “’«
r
Consitunionis’diridedtaVpU^' Spccifi“’lons bi<i documents for constnic '
prior to construction up to the feasibibty sag!'. with commercial sgribusW*
1 0”
TAMS-VLG B.n>AI»' » K.,,
l
Su „
£W*r4
67lBILm STUDIES
Itang Irrigation Project Cott Esti
VOLUME V
,
Unh           Quwtit,
I
k - 15%
Pt'^'^'^cludes ^bankment dam. spillway,
? ^Xork5 ^on awake (!)
M«nc,nal
uxcjvauoc common
fill competed
^^roadway 0.2mthick
^course 0.3m thick
Ckanng
Structures*^misc-------------------- Secondary Canals
■xca^ation. common
rill, compacted
Stopping
Gravel roadway 0.2m thick Base course 0 3m thick
Ctamg
Structures andmisc 10% \kin and Collector Drains Excavation, common
--------:
LS |
L.S i
LS i_____ ~~
- Unit Price 45.431 014 50,064251
T
I
1 I
4.900.000
1,100.000
145.000
39.000
100,000
400
2.5
56
1.5
250
180 6000 2300,000
r
1.147.000
1.851,000
300.000
61.000
157.000
440
250
5.60
150
25 0
180
6000
L.S.      1                  1.829.810              1.829.810
Cort
-45.431,014 50.064251
____39.547 (24.142,500)
12250.000 6.160,000
217300
975.000
1.800.000
240,000
2,500.000
(20.127,910) 2.867.500 10J65.600
450.000
1.525,000
2.826.000
264.000
61
62      C'eannfi
m         1350,000        2.5 1 ha           100                 600
63
Structures and misc
LS       1
400,000
7        Flood Projection Dikes (2)
7.1
71
7]
Dike No 1
Dike No 2
Dike No 3
Pumping Stations and Flap Valve PS No I
PS No. 2
P S No. 3
P S No 4
PS.No 5
P S . No 6
P S No. 7
PS No g P S No 9
I LS
1                     6290,000
U.335.000) 3.875,000
I           60,000
400.000
(I4.865.00C) 6290.000
| LS         1 LS.       1
6.480,000 6.480,000 2.095.000 2.095.000
1975.000)
-5*P Valye _ _
p0 “t’ ”
' 42<3,kV>
DIain,S  Systems
c
PS-fem Sysieros & QUatemar>’ Sv5tcms
kW      20                   800
kW        60                   800
kW        260                 800
| kW           100                 803
kW        210                 800
kW         150                 800
kW       100                 800
kW        70                   800
kW        230                 800
LS.       1
15,000
i km          53                    22,500
km 60
km 1 10
—------------- —
ha
ha
22.500
29300 ______
53,147               755
_53  J  47_      L26°
sS^Q-^«5L-20%jr«r_________________ ’
S^les-2<*
“ha^’. 53J47  .500
ha _ 10,630 __L600_ _ _
16.000
48,000
208,000
80.000
168.000
120,000
80,000
56,000
184.000
15,000
(2.850.500)
1245.500 1.410,000
195,000 (107.091205)
40,125.985 66.965.220 26,573,500
6378,000
rTA
60374,685 363.448.112
16J44111
q
n
Adirum strauon 10%
399j79W4
^^nod
a)
vkMtng,
Cbiptff4
AUob<> River Basin l
Iltq ritf
.
d Development Master Plan
68Year
Civil
_ Capital Cost.
MAE
f-- ■
«« «»• .«6>
i
i
Civil
MAE
I
O A M Costs
2001
2002
2003
2004
2005
2006
2007
2008  _
2009
2010
201!
,2012 _____ 2013
2014 2015 ___
.2016
J0I7
2018 2019 2020  A Ihcreaftcr
i Trans mission
. Lines
Irrigation
A Drulnaoc
A080
17.732
17.732
14,997
8,184
10.919 ____
T runs,
mission
Lincs
Irrigation
A
Drulna
25.97600 42,605.00 61.058  98 40.736  40 22.213 92 22.174  65 25.167 85
5.627 5^529 5.000 4.662
0
__ 17,732
17.732
_ 14,997
8,184 10,947 17.831 17.832 15.098 8285 8,285 5,911
♦
0
0
52 26
87  15
87 15
87.15
93_15
93  15
93  15
93 15
93 15
96.15
99 15
106 56
106 56
106 56
106 56
106 56
r
Power               Total 0—_
0
0__
50 00
50.00
SO 00
50 00
50  00
50  00
50.00
50 00
so on
50  00
50  00
50 00
50 00
50 00
___ 50 00
50 00VOLUME V
_ - """
Hang Dam. upper portion (18,5 km) of the main canal and all other
aJi
1 inc,udeV develops  Of 17 000 h3' includinS 3 first 7 000 module for commercial
. ramies for and 10,000 for diversified agriculture by small holders
, middle portion of the main canal (24 km} and al] other required features for
3?c d *f'clliclVha development, including a second 7,000 ha module of commercial sugar P da second 10,000 ha of diversified agriculture development by small holders
jjjC (*Pefa,’Orl
• r l
I jnC|udes  the lower portion of the main canal (13 km) and all other required
Finally-    phase      Hdrtional    19,147    ha,    including    the    third    7,000    ha    module    of    commercial    sugar
ffjiutes 
for an
.   an additional 12,147 ha of diversified agriculture operations
and development period for each of the 3 phases, including major works, The ™nStnand drainage and on-farm development, would be as follows
phase 1 Phase II Phase ITT
2001 - 2007
2005 - 2012
2011- 2018
Project    finance,    private    concessions    and    design,    specsbid    activities    would    precede    the    above construction and dev elopment
Irrigation 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.
Tie proposed implementation schedule for 1906 to 2018 is presented on Figure 4.3
■* ^-9 Economic Analysis
’ rr*®MIOn Pr°Ject consists of two separate areas of cropping with one area under sugar and the other under smallholder mixed agriculture
for a total of 166%
computation shown in Appendix 4-2 of this report.
Chapter 4NOVEMBER 4,1W
fey w m w;
FIGURE 4.3
ft>wi    •izqooM K>wi» iHwm
CHKJwi
RWW I • lw<j >W*l»
•x>: m
H»v>m _VOLUME V
Economic Return of Crop (Birr/ha)
•ij of cropping for the proposed irrigation project is summarised on Table 4-21 The
ft* ^shown as the number of hectares brought under each of the crops each year As can
n^from the tables, the first acreage is brought under cropping in the year 2004 and then ^tlds up gradually For sugar it is 2016 before all of the acreage is cropped, for mixed cropping the lull acreage is not cropped until the year 2018
Table 4.21 Cropping Build-up (hectares)
Year            Cotton            Maize           Sorgbum         Soya         Vegetables        Fodder         OU Seed
Su?>r
20M              800
1.100
580
400 40 100 300
—
2.3W
2005           1.600
2.200
1,160
800                  80                  200                600
4,700 i
2006            2.400
3.300
1.740
1.200                120                    300                900
7.000
2007            3300
4.400
2.320
1,600                160
400
M00                 7.000
20GS           4,000
5,500
2.9W           2,000                200
500
1,500                1,000
[aio
2:09           4.800              6.600
3.480
2,400                240
600
1.800                9300
5.600
7.700
700
2.100              11,700
2011
2D 12
2;ld —
2t'!5  “
4.060
2,800                280
_ 6.400
8.800
4.640           3,200
320
800
2.400              14,000
_ \20Q
9,900
5.220           3.600                360
900
2.700              1J.000
8,000
a. boo
11.000
5.800           4,000                400
1.000
3,000              14,000
12,100              6,380
4.400
440
1,100
3,300
16300
9.6CO I0.4OC'
jW~
i ? fiAn
jnre--
_ U.200
)4 3DH
15.400
16.500
_ 17.68!
6.960           4,800
480
uoo
3.600
—
7.540
8,120
5300
5.600
520
560
1.300
i.400
j,tW
JJOO
18.700
'll iWl
21.000
8.2 DO
6.000
600                3,500            4.500
21.000
9.323
r 6,499                  643                 1.607
4,822              21,000
4 22 the
,hin8s the ^adu2Unmary °f build’uP of benefits from the cropping is shown This combines two years fOr c '"creasc m acreage and the increase in yields that occurs over a period of
J 0"4 CroPping the h aS il is brought under cultivation As can be seen from the table, for
ttT bu’ld-u of yield*
p
5 not maximised until the year 2022. while for sugar, with a much s > maximum benefits come earlier, in the year 2018
__________________
Min Integrated Development Master PUb
71
Chapter 4PRE FEASIBILITY STUDIES
Table 4.22 Benefit Build-up (million Birr)
Year
2004
2008                     2012
2016
Cotton
(0.1)
10.9
32.5
542
-—_
76 n
Maize
2.6
23.2
46.7
70.3
9lT
Sorghum
0.7
9.1
19 1
29.1
___ ____ LJ 38?
Soya
0.3
5.3
11.5
17.7
236
Vegetables
0.1
0.5
0.9
Fodder
0.3
3.6                         7.6
11 7
--
1      TT
Rr
Oilseed
0.3
3.6                         76
11.7
isT
Sugar
(7.5)                      154.2                    292 9                        388 2                     462 5
i Total
(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 oo-fc 
cost of this production As there is little or no established cropping in the area proposed
irrigation, 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  k are shown in Appendix  4-2, first of all as  financial costs  in millions  of Dollars  and the u economic  costs  in millions  of Birr A shadow' exchange rate of Bin- 7.47 to the Dollar is  usedir 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, a cost-benefit stream shown in Appendix  4-2 gives  us  a set of net benefits  which are the pwc benefits  after all costs  have been met This  net benefit stream gives  an Internal Economic  Rated Return to the Itang Irrigation Project of 13%.
4.4.5 En vironmental Assessment
The Itang irrigation project includes
•    the Itang dam and reservoir,
•    a 55 km-long unlined main canal conveyance,
•    a gravity irrigation system capable of irrigating 53,000 ha of land,
•    a surface drainage system over a gross area exceeding 60,000 ha,
•    a flood protection system composed of earth dikes and drainage pumping stations an
•    a road system for servicing the hydraulic infrastructure.
The Itang dam will impound the Baro River about 30 km downstream of Gambcla Hs in the flood plain of the Gambela Region The crest length of the dam is 5,000 m. its height 14 m and its construction will be an earth embankment The reservoir will inundate to contain 290 million cubic metres (mcm) of water Its normal minimum operating
El 429.0 and its maximum level is at El 431 6 m The mean annual flow of the Baro location is estimated to be 390 mVs. Discharge from the dam will be diverted to
TAMS-ULC Baro-Akobo River Basin Integrated Development .Master Planrf ^^STUDfES
VOLUME V
^^Ltely 53.000 hectares The main canal will be designed to convey a peak 
d^«e
'"^section discusses the potential benefits of the reservoir other than those associated
/ The flood surcharge volume of the reservoir is 170 mem in addition to its active ®^mcra No significant flood attenuation is anticipated from the reservoir operation
< heries The study by Selkhozpromexport (1988) estimated that the Abobo reservoir
could produce an annual catch of 100 tonnes for its 2,210 hectares reservoir
'harvest subject to confirmation by feasibility study, would give a total annual
p^onofabout 320 tonnes
.  Arnone  the  mitigations  recommended  by  this  assessment  is  the  total  clearance  of Loadable  material  from  the  reservoir  area  The  woody  biomass  of  the  dam  and  reservoir  site has not been surveyed other than in the context of the 1995 H 'ocxA Biomass Survey by Theriault Using his results, the reservoir lies in an area whose potential dry woody biomass lies between 10 and 30 tha For the area of the reservoir (71 km ), this translates into a potential fuelwood
supply of between 71,000 and 213.000 tonnes At 5 Birr per 20 kg bundle of fudwood, its gross resaie value, exclusive of the cost of collection and preparation, is betw een 18 and 53 million Birr (USS 2 8 and 8 5 million)
Rtcessiw 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 in Africa The Master Plan map of agricultural systems  denotes  the reservoir as  lying on the border between shifting cultivation ^erghnn dominant) and pastoral systems  The section on subsistence agriculture in the project settmg describes the role of recession agriculture, which provides between 2 and 3 crops annually 
opportunities  are  not  in  competition  with  irrigated  agriculture,  but  complement  it  in  ways Prov^c     additional   project   revenues   while   reducing   noxious   shoreline   vegetation   It
tie   area   t0     contr°l'e^   however   Excess   livestock   would   deplete   the   natural   vegetation   of appropriate fim/0Wn Cana^ ‘ destroy crops, and starve unless their numbers were kept within
2
s
■^P|°c^dSettinVCSCnb€d aAjtq. • result livi
in this report gives a rough evaluation of the manure-P and manure-
Jstock  grazing in the reservoir area Exposed on the surface and
FOt’ chan^ng tT eVaporat^on insolation, horse pats, cow pats, even elephant pats  dry  out and ^rations  oT?0*0118 comP°ncnls to ones  that are more or less  benign The use of high * * Wod of tin, evvonrung medicines  can produce pats  that are toxic  to maggots, extending
rc quired for decay to take place.
15er Bs»in Integrated DevelopaHnt Muter PUn
Chapter 4PREFEASIBELm STUDIES
Negative emironmental impacts and their mitigations
Large dam projects cause irreversible environmental changes over a wide Be
thus have the potential for significant impacts The area of influence of a dam^ ^ from the upper limits of the catchment to for downstream While there are direcT^'01 impacts associated with the construction of the dam, the greatest impact en'1ron->h impoundment of water and alteration of water flow downstream These eff &Orn impacts on soils, vegetation, wildlife and wildlands, fishenes. climate and humS” the area The dam s indirect effects include those associated with the bui]din Ta °
3
2
of the dam, the operation of the reservoir and the development of agriculturJ * j municipal activities made possible by the dam.
P  PUla,,0"J 
n Un'e^e
a ' "ldu«na[ y
The  negative  environmental  impacts  that  result  from  dams  and following:
•    Construction camp.
•    Roads,
•    Dam and appurtenant works,
•    Dislocation of people.
•    Lossofland
■ Lossofhistoricor 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
reservoirs could include tu
Construction farnp Construction camps usually compnse quarters for between 200 and 600 nut and contain showers, cooking facilities, toilets, generators, fuel dumps, cement machines, park”} areas — everything needed by a small town. Their design is usually temporary, although w® 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 exte possible, trees should be left standing to provide comfort for the workers as well as supply * source once the camp is decommissioned If people are to be resettled to provide space for 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 sig^  ®
60
1
no precautions are taken. Ideally, such timber should come from the area of ,l impoundment. Outside that area, its impacts are identical to those of logging destruct^ native vegetation and disturbance to soil and water To the maximum extent possible, the p ■b should make use of such materials as plastic and metal sheeting, plywood and concrete
TAMS-ULG Baro-Akobo Rher Basin Integrated Development Master Plan
74n rn STL'DIT5
.^1 powerhouse will create msgmficant unpacts to the environment, to keep amP e'C ^ the powerhouse should be located away from regents and receive regular
^ tenan<e
VOLUME V
supply,     lf       il       is       a       largC       COUld       Create       drawdown       t0       lcveJs        Wow     the     bottoms 
rte camp *raJtf fl foea y
cotnfl*’**
households could be compensated by receiving camp supplies or by
fb  We\ells      rebored      Ideally,      nearby      households      should      be      relocated      before      the
hould be incinerated at a location removed from the camp and nearby households 
Solid wlSte Sf°
ev a
, ge facilities should bear in mind whether or not the camp will continue to be
i
i
t
i
t
i
design o deconUTUSSloning If it is to continue in use, then primary sewage treatment is 
used ’*'* u extensive septic systems might be permissible
required, otherwise.
The construction of the ltang Dam requires 1 km of road improvement Roads have
wn to be an important contributor to soil erosion, primarily because they concentrate and
^bute 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 Sudness) 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 safety  pass  the 25-year flood and the minor structure to safely  pass  the 10-year flood Temporary loads  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 historical or
cukural significance unless the means to control trespassing to these areas are available
nc  mitigations  of  the  potentially  negative  impacts  of  roadways  rest  with  competent  engineering '' on^Itudlna'   drainage   is   likely   to   require   a   raised   bed   and   ditches   Cross   drainage   should
CuX °astin® cl«nnels  and be designed to accommodate debris  as  well as  water and sediment with X °Utflows should be constructed to a level below the stream bottom so as  not to interfere
•hey   discta?386    a<IuaUc    life-   Culverts   on   steep   slopes   may   require   an   energy   dissipator   before the   Project   dBe    °nt0    unPro‘ected   land   A   Soil   Erosion   Control   Plan   should   be   developed   during ^Wolline   Xi811    aqd   Precede   the   onset   of   construction   Its   purpose   is   to   provide   guidelines   for
erosion, sedimentation and pollution
de «ly identifies C°n5ro' Plan describes the location and type of controls to be implemented It
J er<*ived problXT'3'resources. such as wetlands and primal forests, that require protection
. should contact *ch ^hly erodible soils and unstable slopes, are clearly marked. The
S C drainage information, such as stream patterns, watershed areas, and the
'ocation ofu !
h lhe foUowinp •draul,c structures The erosion control measures should be in accordance Principles
i
Integrated Devebopment Master Plan
75
Chapter 4PREFEASroUJTY STUDIES
VOI%
Limit the time and area of exposure The potential for erosion is greatly red
size of the disturbed area is small or its duration short In some instances stahi
lf
take place as part of construction - it would be wrong to wait until the fin,! 1731,0
,1
established
*
Retain sediment on the site This principle is achiev ed by using devices that flit
from runoff or that detain runoff so that heavy particles will settle It in. clud erSedln’ei’ materials such as silt fences, straw bales, brush barriers, and sediment traps
Manage only the sediment and runoff from the site. For this discussion we are
only with Itang Dam, not with regional management of runoff and sediment IX^
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 embankment is estimated to be 3,450,000 mJ Most fill will come from the reservoir area uV
its potential impact is mitigated by inundation Approximately 210,000 nr of nprap are
required, possibly to be quamed from the koppies that scatter the plain The koppies are not so common that they lack uniqueness, however, particularly in terms of wildlife habitat They wiD
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   kt dislocated  by  the  Itang  reservoir  The  World  Bank  resettlement  criteria  for  dislocated  peope 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  pins assets (estimated at USS 500), they become USS 884 per household or USS 628,000 for the III households
2
Loss of land The reservoir will impound 71 km The worth of its standing ti mber as dry woofr biomass has been estimated in a previous paragraph The previous assessment shows that ’I households risk being relocated It is estimated that lowland households cultivate on aven?
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 wort of the lost agriculture (less assets) is 570,000 Birr (USS 91,000) per year
Loss of histone, cultural or aesthetic features These components were not assessed at this b of study but remain for feasibility investigations
Loss  o f wildlife habitat Itang Dam, reservoir and canals  occupy  part of the northwest^^ of Gambela National Park. The park  is  severely  degraded and its  wildlife P°Pu^t,°n^caSjbi]irr However, the wildlife and habitat are issue that require additional study during
investigations
Much of Gambela National Park is already occupied by a state farm and Abobo $0^ reservoir, and is dissected by connecting roadways Poaching by refugees and t e reported in the area
TAMS-ULG Baro-Akobo River Basin Integrated Development Master Plan
76t
VOLUME V
ivnoTpromexport (1988) described the apparent permanency of migratory routes ^ iess> Proposed canals leading from Abobo Dam These traverse the canal route at
vtcim’y gvery 1 per every I 0 to 1 5 km, and are something to be preserved, if further >s£.‘l»sassessn,H"
f ■urt,7tJc
riana reservoir is shallow (with an average depth of 4.1 metres)
broad (1
reseTvofr area) The water will be warm, oxygenated along its periphery, and habitat for aquatic growth Drawdown during the dry season mav allow
feebly   ^,|   rance,   particularly   if   the   landscape   is   used   for   controlled   grazing   and   agriculture
for   weed   c   $
fi sh
’      inhabit   the   reservoir   At   this   level   of   study,   it   is   not   possible   to
rJ if pW°P - h of wecds will be problematic for reservoir operations
•
rl
quality- Water quality is affected when large amounts of tropical
flooded   by   new   reservoirs.   The   two   important   parameters   to   the   process   are   the
vf 8eUtl0^ j
t) oma5S     (estimated   as   dry   woody   biomass   between   10   and   30   tonnes   per   hectare   for
an ”Unt °d the residence time of the water in the reservoir From a totally  empirical assessment 1 liana Reservoir, it would seem that the short residence time coupled to the small reservoir ° ' would place the reservoir out of the severe risk  category  For the purpose of this rtfeasibility  study, it is, however, recommended that the reservoir area be totally  cleared of all biodegradable biomass
Ians  will be warm during the low flow season, contributing to low dissolved oxygen concentration and thermal stability  Wind turbulence will agitate the surface and possibly contnbute to some mixing of surficial water layers, but this  could be minimal if aquatic  growths dev elop 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 Jeoy  may  not be apparent along the reservoir fringe Because the irrigation intake is  along the
am side rather than the centre, the problems  of reservoir water quality  may  not be apparent to Asia- users  during the early  irrigation season Later in the year, when chemical processes  become
t active due to increasing water temperature, problems of taste and odour may increase
discussed above, tn the hydrology and reservoir operation sections, be used to'0" °f reservoir >  anticipated to be rapid, however, no reliable measurements can
s
Puerto infa.PP°hn I1”8 ass5ssment A sediment measurement campaign should be undertaken,
r «servoirk ,« feasibility study At the present level of study, sediment accumulation in the maied to be 13 6 million cubic metres per year
Th
’ SSessed dtirwth nC rcservoir may interrupt fish migrations, but this has not been directly 
:o ^<iered *            6 COUIS< of this or previous studies A fish ladder and hatchety should be
Wd'8ard t0
At thiS leVel of Ptefeasibility study an assessment of the lung reservoir
* lh* Project are6 atCd diseases is speculative; only some indications can be drawn from and> indeed, from outside EthiopiapREFEASBItm' STUDIES___________________ ____________
tog s
.  shallow.
■ „ w^rvoir will favour shoreline growths that provide the breed,,. ,
other insect earners of disease. Fast canal
for "?T jXble breedina habitat for the By carrier of Onchocerciasis The potentiaj fw.co* — •“-*'* “,he"levd s
The   risk   of   malaria   and   other   diseases   related   to   mosquitoes,   griats.   midges,   and   othe,. carriers   that    breed   or   depend   upon   waler   (yellow   fever,   dengue.   Onchocerciasis   )   M from   being   seasonal   to   becoming   perennial.   The   increase   wiU   result   from   improved   bre^J habitat   offered   by   the   reservoir   and   its   shoreline   vegetation.   Some   of   the   risks   associated» these   diseases   can   be   reduced   by   controlling   wetland   vegetation,   possibly   by   recession   grjZ
Anti-malarial   programs   using   pesticides   such   as   DDT   pose   their   own   set   of   hazards   and^ and    are    not    recommended    given    that    many    of    these    substances    are    banned    SinJ chemoprophylaxis   is   at   best   suitable   only   for   short-term,   non-immune   visitors   to   the   project^
The   development   of   immunity   and   treatment   of   the   population   living   near   the   reservoir   is,   5
now, an admittedly partial solution
The literature associates rivers with outbreaks of trypanosomiasis, but information about fa
disease is fragmentary and inconsistent Selkhozpromexport (1988) reported an unconfirmed
cases of trypanosomiasis in the upper Gilo River, but this is believed to be adjacent to fa
lowlands The Gambela hospital reported 1 case in 1981 and 7 cases in 1985. Feasibility stuie
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   carriers   of   Leishmaniasis   eb lower basin There is no information about their continued absence
The   fly   associated   with   Onchocerciasis   prefers   fast,   shaded   streams   for   its   egg   laying,   and   3
make use of canals  where these become overgrown with vegetation The removal of vegeuox either side of canals  is  one obvious  control, the use of pesticides  another, thought these pose tie own set of risks and costs
The snail carrier of Schistosomiasis  is  reportedly  absent from the Alwero fa® (Selkhozpromexport, 1988), it is  also absent from the Baro Different alternatives  are poss(! to 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 1° P* ^- problems arriving, if any, at the existing irrigation project in the Gambela plain, i.e at the reservoir, should be studied and used in the elaboration of the environmental impact ass655
1
Conflicting demands Jpr
Provisional minimal continuous releases from the !t«®-j
computed at 8 percent of mean annual discharge or 31 m /s. Feasibility studies will be
3
re( l
to eva uate the effectiveness of this discharge to sustain present populations of water org ,. and competing water users The present study has not been provided with sufficient TAMS-ULC B.ro-Akobo River Benn IntegraCed Develop, Master PUr?
78
Cb*P|f,JpRfFEASIBBLrry STUDIES
compute    a    flow    duration    curve    based    on ^uirements are usually estimated
No information about water rights downstre doftllstreaniusers will be afFected AccessuT °fItan8hasbe«, r
Wrftoo non-lMkj- aquifers offer another
The map of there is no pressure on laud £Ms ^"on suPpo„
dty ..
V °L(JArt v
B°»
I(a
rfta sbility
79PREFEASIBILITY STUDIES
APPENDICES
TAMS-ULG Baro-Akobo River Bai in Integrated Development Muter AppendicesAPPENDIX 2-1
GEBA HYDROELECTRIC PROJECT Detailed Cost EstimatesI
I
Igeba hydroelectric project
PREFEASIBILITY STUDY
TAMSContuttanfe inc 04-Dec-M
COST ESTIMATE Max. Res. Level: EL 2,170 Dam Type:
Infl Capacity: 112 MW & 72 MW
Earthfili
Amount
Local
Foreign                ToLal
jefl1 10
10 JO
W
If .1 5.0
^^RTENANT works
p Si«*aTE  WAYSNo
r
^ !^‘TERWAYSN°2
cS
7,085,981
1,155,196
1.907.561
931,915
3.038,545
28.343,923 4,820,783 7,630,245 3,727,662
12,154,581
total civil works
14,119,298          56,477.194
35,429.903 5,775.979 9,537,807 4,659.577
15,193.227 7QJ96.492
W
20
3.0
40
5.0
6.0
o electromechanical equipment
J^AND APPURTENANT WORKS
POWER PLANT No.1
Sersion waterways No.1
POWER PLANT No.2
□(VERSION WATERWAYS No 2
transmission LINES
TOTAL EQUIPMENT
282 300
5649 424
21,800
3,799,748 21.600
6,300.000 16.07S !69
t
1,131,200 46.215,796
86.400 32,092,782
36.400 25,200.000
104.812.578
1,414,000 51,865,220
108.000 35.892,527 I
108,000
31,500,000
120,887.747
total BASIC COST
Physical Contingencies 20% Engineering and Administration 10%
TOTAL CONSTRUCTION COST
30.194,468
6,038.834
3.623.336
39,856,698
161,289,771 32,257,954 19,354.773
212.902.498
191,484,239 38,296,848 22,978,109
252.759,196BARO-AKOBO PROJECT Integrated Master Plan
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE Max. Res. Level: El. 2.170 Dam Type:
InsL Capacity: 112 MW 172 MW
E»rthfi||
Item
No. DESCRIPTION
A: CIVIL WORKS
1.0 DAMS AND APPURTENANT WORKS
1.1        Preliminaries
1.2
1.3
1.4
1.5
1.6
1.7
Access Roads
Diversion Tunnel
Cofferdam
Embankment Dam Spillway (separate from dam) Low-level Outlet
*•251,588
1 562,892
4.220,322
581,078
10,722.192
6,846,452
159,401 ’<
1
TOTAL 1.0
2.0        POWER PLANT No.1
2.1
2.2
2.3
2.4
2.5
2.6
2.7
Preliminaries
Access Roads
Power Intake Penstock (surface) Powerhouse (surface) Tailrace Channel Switchyard
TOTAL 2.0
1.062.897
390.723
1.055,080
145.269
2.680,548
1.711,613
39,850
7,085,981
173,279
85,421
126,252
216,479
487,239
0
66.525
1,155,196
3.0
3.1
32
3.3
3.4
DIVERSION WATERWAYS No.1 Preliminaries
Access Roads Diversion Intake Diversion Canal
286,134
15.819
186.930
1.418,679
28,343,923
693,117
341,685
505,006
865.916
1,948,957
0 266,101
4,620,783
1.144,537
63,275
747,719
5.674,715
TOTAL 3.0
is
c
s
'X
iQ
E
LI
14
1
V
sr
4.0
4.1
4.2
4.3
4.4
4.5
4.6
4.7
POWER PLANT No.2 Preliminaries
Access Roads
Power Intake Penstock (surface) Powertiouse (surface) Tailrace Channel Switchyard
TOTAL4J
5.0
5.1
5.2
5.3
5.4
DIVERSION WATERWAYS No.2 Preliminaries
Access Roads Diversion Intake Diversion Canal
TOTAL 5.0
1,907,561
139,787
17,401
126.252
120,631
453.004
0
74,841
455,797
39,547
186.930
2.356.372
3,038,645
7,630,245
559,149
69,602
505.006
482.524
1,812,018
0
299.364
3.727,562
1.823,18?
158.187
747.719
9,425.488TAMS Consultants, Inc.
W-DccJC
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
M-x.P«.LewfcW, 1,171 tJamTrt,,; EartMHI
inrt. Capacity: 111 MW 4 71 MW
Cost L*ve|:                    Jan-M
Amount
Local
Total
ceSS^j^MECHANICAL bUUlPMkN I
^HdI^naNT^
PA ...nrji/ to the dam
Ptnrti- 5^PJ'
|khead
cates * Low Level Outlet
^Presure Slide Gates - Low Level Outlet
40,000
48,000
1,043,200
TOTAL 1,0
POWERPLANT NO-1
Power intake Gates
Penstock
Inlet Valves
Turbines. Governors and 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
TOTAL 3.0
10,000
12,000
260,800
282,800
21.6D0
620,040
296,000
1,180.000
1,344,000
25,000
151,200
534,400
280,000
483,600
513.584
5,649,424
21.600
21,600
21,600
361.114
204.000
963.000
915.000
25.000
108.000
322.000
186,000
348.600
345,431
1,414,000
DIVERSION WATERWAYS No.1 Divernon Intake Gates
46.215,796
86.400               108.000
86,400
103,000
POWER PLANT No.2
Power Intake Gates
Penstock
Inlet Valves
General ^    mors and Turbine Equipment
Ove
a              fiera10r Aux liary E   u    ment
Powerti  X crane             '       ^ 'P
0l
Sialion xStaZ p.      '    Equipment
echan cal
Sr
^asured Hems
,
TOTAL 4.0
3 799,745
32,092,782
35,892,527
AYS
a*3------------
21.600
86.400
108,000
TOTAL 5.0
21.600
86.400
SC Jans h"! !ran P p *1 to P P. #2
■ *1 to Gilgel Gibe
2,625,000 28,875,000
TOTAL 6.0
6 300,000
31,500.000BARO-AKOBO PROJECT Integrated Mester Plan
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
TAMS Consultants. Inc.
M-Dec 41
COST ESTIMATE
Max. Res. Level: El. 2,170
Unit Prices
Dam Type:         EarlhflU Inrt. Capacity; 112 MW <72 MW
Cort Level: Jen-SO
Amount
Hem
No.
DESCRIPTION
Units
Local
USI
Foreign
USI
Tolal
USI
Quantities
Local
US I
Foreign
USI
Total
USI
A: CIVIL WORKS
1.0 DAMS AND APPURTENANT WORKS
1.1 Preliminaries
1.1.1
Mobilization
%
1500
1500
15 00
1.062,897
4,251.588
5.314.485
1.1 2
Land acquisition
ha
2,250.82
000
2,259 62
0
0
0
0
113
Site clearance
ha
1 694 67
6,779 46
8,47433
0
0
0
0
Subtotal
1.062.897              4,251,588              5.314,485
1.2            Access Roads
12 1
Road Improvement
km
7909 37
31.637 46
39,546 85
12
94 912
379 650
474.562
1.22
New Road
km
17.40061
69,602 46
87,003.07
17
295,810
1,183.242
1,479 052
1.2.3
Stream Crossing
No
22,596 20
90.392 80
112991 00
0
0
0
0
Subtotal
390,723               1.562.892              1,953,614
1.3            Diversion Tunnel
131
Portal excavator
cu.m
136
5.42
6 76
5000
6,780
27 120
33.900
1.3 2
Tunnei excavation
cu.m
10 17
40 66
50 85
21.237
215 980
863,921
1,079,901
133
Tunnet support - rock bolts
T
1 355.69
5 423 57
6.779 46
53
71,591
286,364
357,955
1.3,4
T tonei support - shotcrete
sq m
565
22.60
28 25
1.602
9 051
36,205
45 257
135
Tunnei support - arches and ribs
T
451 96
1,607 86
2,259 82
5
2 260
9039
11 299
1.3.6
Concrete Hnmg
cum
40 60
162 70
203 38
5,781
235 148
940 592
1,175.740
1.3 7
Structural concrete
cu m
25 99
103 95
129 94
800
20790
83 162
103,952
1 36
Formwork
sq m
1017
40 68
50 85
13200
134 244
536 976
671 220
1 39
Sleet rrtnloccemcnl
T
248 58
994 32
1.242 90
751
186 684
746,734 I        933.416
M3 10
Drilling lor grouting and drains
m
15 82
63 27
79 09
4260
67.385
269 539 /             336 923
U3.11
Groubng
T
11290
451 97
564 96
466
54 925 /                219 702 /              274 627 /
\V312
Unmeasured Sems
%
500
500
5 OO
50 242 |                200 DM /               25! 2fO /
1,063.000              4.220.322             5,275.402GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Max. Re*. Level. EL  1,17*
/
/
Dem Type;
nd. Capacity:
earth fl*
112 MW & 72 MW
11
1 Units | US S
UnM Price*
Foreign               Total
USS                   US 1
I
Amount
I
htem
[No.            J DESCRIPTION
Local
Quantrtle* | USS
Foreign \         Total        \ US S          I          USS          \
A: CIVIL WORKS
1.4 Cofferdam
/>«
Foundation excavation - Common
cum
072
290
3 62
18.875
12218 ]               48 870
61.058
h.42
Foundation excavation - Rock
cu m
1 81
723
904
0
0
0
0
f 1.4.3
Borrow excavation - Earth
cu m
068
2 71
339
102 400
69.427
277.709
347 136
144
Borrow excavation - Rock
cu m
096
384
4 80
4500
4 320
17 280
21,600
1.4.5
Haufing HI material (over 2 km)
cum/km
0 10
041
0S1
0
0
0
0
1.4 6
Unprocessed fill (placement)
cu.m
0 45
1 81
226
102.400
46 265
185 139
231.424
14 7
Processed fill (piacemenl)
cu.m
1 38
5 42
6 76
4.500
8.102
24.406
30.510
148
Unmeasured Ham*
U
500
5 00
500
6918
27,670
34,566
Subtotal
581,076               726,345
1.6
15 1
1 5.2
153
Embankment Dam
Foundation excavabon - Comnxxi
Foundation axcavalton - Rock
Borrow excavartion - Earth
154
Borrow excavation ■ Rock
11.5.5
15 7
15 6
Haulmq fill material i.over 2 kmi
Impervious ccxe
Unprocessed M (placement)
Processed fW (placement)
cu m
cu m
cu m
cu m
cu m<km
cu m
cu m
cu.m
cu m
1 5 10 Dralna transitions.
15 11
cum
Rip-rap ( placement)
Drilknq to* grouting and drains Grouting
Unmeasured Heme
cu m
m
%
0 72
1.81
0 56
096
0.10
2 26
0 45
1 36
3 30
3 39
1 13
11 30
2 90
7 23
2.71
3 54
0.41
9 04
1 81
5 42
13 56
13.56
4.52
45 20
3 62
904
3.39
4 60
0 51
11 30
2 26
6 78
16.95
16 95
5 65
56 50
327,000
16000
150 600
0
0
637,500
642 600
0
64 100
0
19900
5200
145.269
236 748
28 928
102 107
0
0
1 440 750
290,455
0
285 099
0
22 467
56 7«J
946 992
115712
408 427
0
0
5,763 000
1 161 821
0
1,140 396
0
S9 946
235 040
1,163 740
144 640
510,534
0
0
7 203 750
1 452 278
0
1 425 495
0
112 435
293 800
15 12
1 5 13
1.5 14
T
11299
451 97 5 00
564 96 5 00
775
87 569
127,645
350 275
510,581
437 644 638 226 |
Subtotal
2680,546          10,722.192          13.402.740BARO AKOBO PROJECT Integrated Matter Plan
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
TAMS Consultants, Inc.
OI-Dec-ll
COST ESTIMATE
Max. Res. Level: El. 2.170
Inst. Capacity; 112 MW A 72 MW
Dam Type:      Earth Ml
Cost Level:           Jin-06
Unit Prices
Amount
Item
No.
DESCRIPTION
Units
Local
US 1
Foreign
USI
Total
us$
Quantities
Local
USI
Foreign
US 1
Total
USI
A: CIVIL WORKS
1.<Spillway (separate from dam)
Bulk excavation - Common
1.6 1
cum
0 72
290
362
288 000
208 512
834 043
1.042 560
162
Bulk excavation ■ Rock
cum
1 81
7.23
9 04
178 000
321.824
1.287 296
1 609 120
163
Structural excavation ■ Rock
cu m
4 52
18.08
22 60
0
0
0
0
1 64
Mass concrete
cu.m
1806
72 31
90 39
9400
169.933
679 733
849.666
1 65
Structural concrete
cu m
25 99
103 95
129 94
13 800
353.634
1.434 538
1.793,172
1 66
Formwork
sq m
1017
40 68
50 85
6.200
63 054
252 216
315,270
167
Steel reinforcement
T
243 58
994 32
1,242 90
1.015
252.309
1 009 235
1,261.544
1 66
DnXing for drains
m
11 30
45 20
56 50
7.950
89 835
359 340
449,175
169
Dril’ing for grouting and drain»(fiom gall)
m
15 82
63 27
79 09
250
3954
15818
19,773
1 610
Anchors (including Drilling and Grouting)
T
2 982 96
11 931 35
14.914 81
53
158.097
632 388
790,485
1 6 11
Grout ng
T
11299
451 97
564 96
35
3 955
15819
19.774
1 6 12
Unmeasured items
%
500
500
500
81 505
326 022
407,527
Subtotal
1.711.613            6.846.452             8558.064
1.7 Low4evet Outlet
171
3 ortai excavation
cum
1 36
5 42
6 78
0
0
0
0
172
Funnel excavation
cu m
10 17
40 68
50 85
0
0
0
0
1 73
Shaft excavation
cu m
1808
72 31
90 39
0
0
0
0
1.7.4
Tunnel support - rock bolts
T
1 355 89
5,423 57
6 779 46
0
0
0
0
17 5
Tunnel support - shotcrete
sq m
5 65
2260
28 25
0
0
0
0
1.7 6
Tunnel support - arches and
T
451 96
1.807 86
2 259 82
0
0
0
0
177
lining concrete
cu m
40 68
162 70
203 38
0
0
0
0
17 8
Structural concrete
xu.m
25 99
103 95
129 94
383
9 953
39814
49,767 /
U.7.9
Formwork
10 17
40 68
50 85
1 531
15 570
62 281
77 851 /
\l 7.10    \steel reMMorcarrwnl
248 58
\l 7 11    ItWftg lor grnuUny anrt <li i»inv
T
904 32
1 242 90
50
12 429
49 718 /               «2 14S
lm
15 82
83 27
79 09
0
O
\A_* T 1_
V Mi     \Ci* ■ A'lrv^j
117 OO
<51 07
0<14 (M
IT*
O
o
-----------
n nri
s cxi
e. 1X1
---------—T
-------------. t
----------- —------ A—
O/
----------------- o Jgelja mvdroel-EOTkic: projc^t
preffasibility study
COST ESTIMATE
Max. Rti. Level; EL   1.170
Dem Type:
net Capacity;
Earthnn
113 MW I 73 MW
ir
Ittofn         I
/No [DESCRIPTION
Unit Prices
I
Amount
\
| Uniti             t
' Local
US*
Foreign
US |
Total         1
US*
Local          I       Foreign         !          ToUl           \
Quanlltlea
US *
US*            \
A: CIVIL WORKS
J *I
us
2,0 POWER PLANT No. 1
2.1 Prefimlnartes
I 211    MoMttanori
LS
15.00
15.00
15 00
173279
693,117
866,397
212
Land acquisition
ha
2.259 82
000
2,25982
0
0
□
0
,2 13
Silo clearance
ha
1 694 87
6779 46
a.4?4 33
0
0
0
0
Subtotal
173,279              693,117
866.397
2,2          Access Roods
22 1
3ud Improvement
km
7,90937
31,637,48
39 546 85
2
15819
63 275
79,094
22 2
lev/ Road
km
17 400 61
69 602 46
B7OO3 07
4
69 602
278 410
348 012
223
Stream Crossing
No
22 598 20
90 392 60
112.991 00
0
0
0
0
Subtotal
65,421
341.665               427,106
2 3            power Intake
h 3 1 I         Earth excavalion
cu m
072
2 90
362
300
217
869
1,086
I2 3 2           Rock excavehon
cu m
1.81
7 23
9.04
0
0
0
0
R 33
lining concrete
cum
40 68
162 70
203 38
0
0
0
0
234
Structural concrete
cu m
25 99
103 95
129 94
1 350
35084
140,335
175,419
I23.5
Focmwwk
sq m
1017
40.68
50 85
4 050
41 189
164,754
205.943 1
2 3.0
Steel (olntofcemelM
T
248 58
994 32
1 242 90
176
43 750
175000
218 750 I
2.3.7
Unmeasured Itemt
%
5.00
500
500
6012
24,048
30,060 |
Subtotal
128.262
505,006
831.258
2 4            Panstock (surface}
2,4.1
Commas excsvilw
cum
072
290
382
4 200
3.041 (
12163 1               15,204
242
Rock excavelion
cum
1 01
7 23
904
1 223
2,211
8 845
11 056
2 43
Anchor belle
tn
1358
54 23
87 79
0
0
0
0
2.4,4
Men concrete
cu.m
1*08
72.31
90 39
2 446
44 219
176,875
221,094
12 4 5       1 Structural cone rein
cu.m
25.ro
103 95
129.94
0
□
0
0
[2.4 6        Formwork
»q m
10.17
40.88
50 85
fl BB7
91 398
305,501
450 969
2.4.7         Steal lelnlwcemeni
T
248 50
994 3?
1 242 90
225
55 931
273 722
279 653
1? 4 a         Unmeasured Rems
1*
10 00
10 DO
1000
19.660
76,720
IM 400 J
Subtotal
218,470               965 910             1,082.395BARO-AKOeo PROJECT Integrated Master Plan
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultants. inc.
M-Dec-66
DESCRIPTION
I Units
A: CIVIL WORKS
Local
I usi
2.170
Unit Prices
Foreign
I US» |
Type:       Earthfill
I     win * /J  : ____________       Coat Level:
Amount
Total
USI |[Quantities |
Local
|__  USI
Foreign
USI
Jan-91
Total
USI
2.6
2.5.1
Common excavation
cum
2 5.2
072
Rock excavation
290
3 62
11 340
8 210
32 841
cum
41 051
25.3
1 61
7 23
904
Elrthfl
14 200
25 674
102 69-1
cu m
0.45
2.5.4
1 81
226
4 030
Maas concrete
,
2.258
1 822
7 286
9 108
CU.m
1808
72 31
90 39
,
40 820
255
,
163 280
204 101
Structural concrete
cu m
25 99
103 95
129 94
2872
74 638
298.550
,
373.188
2 56
Formwork
sq.m
10 17
40 68
50 85
6 501
66 115
264 461
330 576
2 57
Steel reinforcement
T
248 58
994 32
1,242 90
506
125.781
503.126
628 907
258
Roof, ng
sqm
180 79
723.14
903 93
323
58 394
233.576
291.969
25 9
Blockwork
sq m
904
36 16
45 20
900
8,136
32 544
40 680
2 510
Miscellaneous Metalwork
T
723 14
2,892 57
3 615 71
40
28 926
115 703
144 628
25 11
Slope Protection
sq m
4 52
1806
22 60
980
4430
17718
22 148
2.5 12
Unmeasured Items
%
1000
10.00
1000
44 294
177 178
221 472
Subtotal
487239           1.948.957          2.436,196
2.6
Tailrace Channel
12 6 1        1 Common excavation
1 cu m
0 72 I                 2 90
362
0
0
0
0
262
leu m
1 81 I                 7.23
904
0
0
0
0
I—-=— 12 6 3
■R —
5 00                   5 00
500
0
0
0
- -------------------------------------------------------------------------------------------- 0
0
oOEBA HYDROELECTRIC
PREFEASIBILITY STUDY
COST ESTIMATE
.170                   D>m Type:         EarthOW
IneL Capacity: 111 MW A n MW
Coat Livtii
Unit Price*
Amount
I
Local
US 1
Foreign
us S
Total
US S
Qua nl like*
Local
US 1
Foreign I
□SI            ’
Total         I
us* 1
A: CIVIL WORKS
3.0 DIVERSION WATERWAYS No.1
XI Preliminary*
/if.!         (MoWftsatlcn
li$
1500
15.00
15.00
286,134            1,144,537
1.430,671
312          (land jKqursrtkxi
ha
2,259 02
000
2.259.B2
0
0
0
0
13.1,3     /S/te clearance
ha
1 694.87
6,779.46
8.47433
0
0
0
0
Subtotal
286,134            1J 44,537            1,430,671
3.2 AccettRoad*
3.2.1
Road Im pro vemenl
km
7,909.37
31,637 48
39,546 85
2
15,519
63 275
79.094
3 14
New Road
km
17400.61
69,602 46
87,003.07
0
0
0
0
325
i Stream Cro**mg
No.
22 598 20
90,392 80
112,991 00
0
0
0
0
Subtotal
15,819
63,275
79,094
33 1
Earth tjxrayalkjri
cu m
0 72
2.90
3 62
1,575
1 140
4561
5 702
3.3 2
Rock ejtcavallon
cu m
1 81
7 23
9 04
1 275
2 305
9 221
11.528
333
Mibb concrete
cu m
18 08
72 31
90 39
2 550
46 099
184.398
230.495
334
Structural concrete
cu m
25 09
103 95
129 94
1,350
35 084
140 335
175,419
3 35
Formwork
rqm
10 17
40,66
50 85
4882
49,650
198,600
248.250
33 6
Steel reinlcrcefnent
T
248 56
994 32
1.242.90
176
43 750
175.000
218 750
337
Unmeasured Mem*
%
500
500
500
J
9901 |                35 606 |               44 507 J
Subtotal
186.930
747,719                934,648BARO-AKOeo      PROJECT Integrated Master Plan
TAMS Consultants. Inc.
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Dam Type:        Earttiflll
r
Unit Price*
Amount
litem
|mo.
DESCRIPTION
Units
Local
USS
Foreign
US $
Total
USS
Quantities
Local
USS
Foreign
USS
Total
USS
>:
3.4 Diversion Canal
341
Common excavation
cum
072
2 90
362
52.850
38 263
153,054
191.317
34 2
Rock excavalion
cu.m
1.81
7.23
904
455 000
822 640
3 290,560
4.113200
343
Earth HU from borrow
cuin
1 36
5 42
678
0
0
0
0
3 44
Hauhng fHI material
cum/ km
010
0.41
051
0
0
0
0
3.4 5
Earth fil
cu m
0 45
1.01
226
0
0
0
0
3.46
lining concrete
cu.m
33 90
135.59
169 49
11.235
380 844
1 523.376
1.904.220
34 7
Structural concrete
cu m
25 99
103 95
129 94
0
0
0
0
34 8
Formwork
sq m
10 17
40 68
50.85
0
0
0
0
3.49
Steel reinforcement
T
248 50
994 32
1 242 90
440
109.375
437 501
546.878
34 10
Unmeasured items
%
500
500
500
67.556
270 225
337 781
Subtotal
1.418.679            5.674.715             7.093.394HYDROELEGTRIG F»f*O^&O~T
PREFEASIBILITY STUDY
COST ESTIMATE
Max. Rea. Level; BL  2.17*
Dam Type:
ln«4. Capacity:
EirthfU
112 MW A 71 MW
Coat Laval:
/--------7------------------------------
litem 1
[no.     1 description
Unit Fries*
AitoUtiI
|
/
| Units
Local
USS
Foreign
US 5
Total
US t
Quanfllltea
Local
US t
F deign        \            Total          1 USI             \           USI             \
A; CIVIL WORKS
4.0 POWER PLANT No.2
4.1 Prefainlnari**
/4 1.1        / Mobttzatbn
L.S
1500
1500
15.00
139.787
559,149
698,937
4.1.2      1 Lind acquisition
iia
2,259.52
000
2,259.82
0
0
0
0
4.1.3         | Site clearance
ba
1694.67
«, 779.46
8,47433
0
0
0
Q
Subtotal
139,767
559,149
□98,937
4.2             Access Roads
4.Z1         Fland Improvement
km
7,908.37
31.637.48
39 546.85
0
0
0
0
4.2.2        hlew Road
km
17 400 61
69.602 46
B? 003 07
1
17,401
69,602
07 003
4.2.3         5ilream Crossing
No.
22 598 20
90 392.80
112991 00
0
0
0
0
Subtotal
17,401
69.602
87,003
4.3            Power Inlake
14 3.1       | Earth excavation
cu m
0.72
2 90
3 62
300
217                        869
1 086
4.3 2
Rock excavation
cum
1.81
7 23
904
0
0
0
0
433
Lining concrete
cu.m
40 68
162 70
203 38
0
0
0
0
434
Structural concrete
cum
25 99
103 05
129 9-1
1 350
33.064
140 335
175.410
4 3.5
Formwork
sq.m
10 17
40 68
50 05
4 050
41 189
164 754
205 943
4.3.5
Steel relnlorcernefM
T
248 58
MM 32
1,242.90
176
43.7SD
175 000
218,750
437
Unmeasured Hems
%
500
500
SOO
6.012
24 046
30 060
Bublolal
126 252
506.000
631 256
44             Penstock (surface|
[77T-
Common excavation
cu m
072
2 00
362
2400
1,738
6.950 1                  Q 688
14 4 2
Rock excavation
cu.m
1 81
7.23
9 04
640
1,157
4 628
5,786
4 4.3
Anchor bolit
m
13 56
54.23
87 70
0
0
0
01
4 44
Maaa concrete
cu m
1008
72.31
00 39
1,280
23 J40
92,559
115699
4 45
Structural concrete
cu.m
25.99
103 95
129 94
0
0
0
0
4 46
formwork
aq.m
10,17
40 68
50 85
5,119
52 060
208,241
260 301
44 7
Steel reinforcement
T
248 58
904 32
1.242 90
127
31 570
126.279
157.948
443
Unmeaaured Herne
%
1000
1000
1000
10 966
43,866
54,832 |
Subtotal
120,631               402,524
503,154BARO-AKOBO PROJECT Integrated Master Plan
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultants. Inc.
09-Dac-JS
Mai. Ret. Level: EL 2,170                 Dam Type:
EartMIII
Inst. Capacity:  112 MW & 72 MW
Cost Level:        Jan-96
Unit Prices
Amount
Item
No.
DESCRIPTION
Unda
Local
USS
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign
USS
Total
USS
4.6
A: CIVIL WORKS
Powerhouse (surface)
451
Common excavation
cu m
0 72
290
362
10.800
7.819
31.277
39,096
4.5.2
Rock excavation
cu m
1 81
723
904
11,690
21 136
84.542
105678
4 53
Earth fin
cu m
045
181
2 26
3645
1,648
6.590
8,238
45 4
Mass concrete
cum
1808
7231
90 39
2.345
42.393
169,572
211.965
455
Structural concrete
cum
25 99
103 95
12994
2,717
70,609
282.438
353 047
4 56
Formwork
sq m
1017
40 68
50 85
6.338
64 457
257,830
322.287
4 57
Steel reinforcement
T
248 58
994 32
1,242 90
489
121.556
486 222
607.778
45 8
Roofing
sqm
180 79
723 14
903 93
325
58 755
235.022
293.777
4.5.9
Blockwork
sq.m
904
3616
45 20
729
6590
26.361
32 951
4510
Miscellaneous Metalwork
T
72314
2.89257
3,615.71
18
13.017
52066
65 083
4.5.11
Slope Protection
sqm
4 52
1806
22 60
850
3 842
15368
19,210
4512
Unmeasured items
%
10 00
1000
1000
41,182
164.729
205.911
Subtotal
453.004             1.812,016             2.265.020
4.6
Tailrace Channel
461
Common excavation
cum
072
290
362
0
0
0
0
462
Rock excavation
cu.m
1 81
723
9 04
0
0
0
0
46 3
Unmeasured Hems
%
5.00
500
500
0
0
0
Subtotal
0
0
0
4.7
Switchyard
llLl       | Common excavation
cu.m
072
290
362
20 250
14 661
58 844
73 305 1
1472        1 Rock excavation
cum
1 81
7 23
9 04
0
0
0
|473         iFoundrtrana and ducts
sqm
124 29
497 16
821.45
270
33,558
°
134.233 1 167 792 1
\Sudacinq
1.47
587
734
13.500
19 810
79 272 1                 99090 1
\Unmeasufsd Uem»
K
woo
1000
10 00
8804
27.215 1               34 019 1
7
If
Subtotal
74.IM I
2W .364
J74 205
zHYDROELECTRIC F*I^OJECT
PREFEASFBILITY STUDY
COST ESTIMATE
M«a. Aww. Lwvwl: El. 2.170
Int Capacity; 112 MW A 72 MW
Dam Type:            EarthfUfl
Cowl LavaV
Unit Price*
Amount
\
Ikeni           /
Local
USS
Foreign
USI
Total
US *
Local
US I
Foreign         T         Total           \
[no.         /DE5CRIP71CW
Unite
QutntiUwa
USS            121!1
A: CIV/L WORKS
5.0 DIVERSION WATERWAYS No.2
8.1 Prdlminirtei
/s.1.1     [Mobilisation
LS
1500
15 00
1500
455.797
1,823187
2.278984
5.1.2        1 Lend acquisition
tie
225982
000
2.259.82
0
0
0
0
[s 13         |sda clearance
ha
1.694 87
6,779 46
8.474.33
0
0
0
0
Subtotal
455.797              1,823,187              2,278,984
6.2              Acccaf Roads
5 2.1
Road Improvement
km
7 909 37
31.637.48
39 546 85
5
39.547
158 187
197,734
5.2.2
New Road
Inn
17,40061
69 602 46
67,003.07
0
0
0
0
52 3
Stream Ciotsinfl
No
22,598.20
90 392 60
112.991 00
0
0
0
0
SuMotil
39.547
1 58.107
187.734
(.3 Divwtlon Inlifc*
531
Earth tKcaYabori
cu.m
0 72
290
362
1,575
1140
4.561
5 702
532
Rock excavation
cu.m
1 81
7.23
8.04
1.275
2.305
9.221
11.526
533
Matt cocxtQlt
cum
1808
72 31
90 39
2 550
46 099
184 396
230.495
53.4
Structural concrete
cu.m
25 99
103 95
129 94
1.350
35,084
140.335
175419
53 5
Formwork
•q m
10.17
40 68
50 85
4.882
40 650
193 600
248 250
536
Steel reinforcement
T
248.58
994 32
1 242 90
178
43.750
I75OOO
210 750
5 3.7
Ur measures fterrti
%
500
500
500
8 901
35,606
44,507
Subtotal
108,930
747.7t9                  934.648BARO-AKOBO PROJECT Integrated Maaler Plin
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Mm. Res. Level: El. 2,170                     Dam Type: Earihflll
TAMS CmsulUnli. hie.
M-Dec-SB
________________________________Ind. Capacity: 112 MW3.72 MW_________________ Coat Level:           Jan-H
Unit Prices
Amount
Item
No. j
DESCRIPTION
UnMs
lot
Foreign
USS
Toial
US*
Quantities
local
usi
Fotelgn
USS
Total
US I
A: CIVIL WORKS
5.4 1
'Common excavation
cu.m
0.72
290
3.62
96,600
69,938
279.754
349.692 1
54.2
Rock excavation
cu.m
1.81
7.23
9.04
840,000
1,518.720
6 074.060
7 593.500
5.4.3
Earth frfl from borrow
CUT
1.36
542
6.78
0
0
0
0
544
Hauling til materiel
cum/km
0 10
041
0.51
o
0
0
0
5.45
Earth fill
cum
045
U!
226
0
0
0
0
54.6
Lining concrete
cu.m
24 06 |
99.43
12429
18,540
460 867
1.843,469
2,304,337
5.47
Sliuctural corKrtl?
cu.m
2599
103.95
129,94
0
0
0
0
5 4.6
Formwork
eq m
1017
40.68
5085 |
0
0
0
0
549
Steel rdnforcemenl
T
248 58
994,32
1.242 90
763 |
194.638
778.653
373,191
5.4 ID
Unmeaii™) (wni
%
500
5.00
500 1
112.208
448,033
561 041
SublolaJ
2.356,372              9.425,486            11.781,860PREFEASIBILITY STUDY
COST ESTIMATE
Max. Raa. Lavalr El-   2.178
Dim Typa:
jnsl. Capacity:
EartWRII
112 MW A 72 MW__________________
Coat Level*.
Amount
Jan-88
Ittern       1
1 Units
Unit Prices
Foreign
USS
Total
Local T      Foreign         1        Total           \
US 8            Quantities                US S
US 8           1         US $           |
/No
10
B: ELECTRO-MECHANICAL EQUIPMENT
dams AND appurtenant WORKS
/7T“       /            suppty Io ttltf CUT)
LS
10000 00
40 000 00
50,000 00
1
10000
40 000
50.000
r—
f77-------- Ihigb Pressure Slide Gates • Low Laval Outlel
llnlake and Bufahead Galea • Low Lewi Outlet
each
3000 00
12 000 00
15.000 00
4
12 000
48 000
60 000
each
65 200 00
260.600 00
326 000 00
4
260,800
1 043.200
1.304 000
Subtotal
212.800
1.131.200
1.414.000
POWER PLANT No.1
i2 7
2B
29
2 10
2 11
Station Au»iiwy Mochankai Equipment Station Auxiliary Electrical Equipment
Mm I ranalonnera________________ SwHchyard EgicpneN___________________ Uncnaaaured llama
151,200 00
534 400 00
70.000 00
483 60Q00
10
1   360.800   00
4,809,800 00
630.000 00
4,352,400     00
10
1 512000 00
5.344.000 00
1
1
25 OOP
151200
534,400
700 OOP 00                               4           280 OOP
1
Subtotal
4 836 000 00
10
483 600
513 584
8.848.424
3.0                DIVERSION WATERWAYS No.1
250 000
5   1 .3 .54 14 2, .000000
2800 000
4 836 OOP 4,715 020
81.886.220
2 00 00
9,600 00
12,000 OO
I
86.40©
ToS.OOqJ ioo.oooBARO-AKO0O PROJECT
I rrlegratsd Mader Plan
TAMS Consuitints, Inc.
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Max. Res. Level: El. 2,170
Dam Type:            Earthfill
Ind. Capacity: 112 MW A 72 MW
Coat Level:         Jan46
Unit Prices
Amount
Item
Na
DESCRIPTION
Unlit
Local
USS
Foreign
US*
Total
US*
Quantrties
Local
US*
Foreign
US*
Total
US*
B: ELECTRO-MECHANICAL EQU      PMENT
4.0 POWER PLANT No.2
41               Power Intake Gates
each
240000
9 600 00
12,000,00
9
21.600
86,400
108 000
42
Penstock
T
494 00
1,976.00
2,470.00
731
361114
1.444.456
1.605.570
4.3
Inlet Valves
each
68000.00
612,000 00
680,00000
3
204,000
1,836 000
2,040,000
44
TurWnes Governors and Turbina Equipment
each
321 000.00
2.069,000.00
X210.000.00
3
963.000
8.667000
9,630,000
4.5
Generdora and Generator Auritiary Equipment
each
305 000.00
2.745,000.00
3050,000 00
3
915,000
6,235,000
9.150.000
46
Powerhouse Crane
LS.
25000 00
225 000.00
250 000,00
1
25 000
225.000
250.000
47
Station Auxihary Mechanical Equipment
LS.
ioe.ooo.oo
972 000 00
1,080 000 00
1
108.000
972.000
1,060,000
4B
Station Auxiliary Electrical Equipment
LS.
322.000.00
2,898.000.00
3.220,00000
1
322.000
2898,000
3220 000
IE
Mah Transformers
each
62 000 00
568.000 00
620.000,00
3
186,000
1,674,000
1.860 000
410
Switchyard Equvpmanl
IS.
348.600.00
3.137.40000
3486.000 00
1
348 600
3 137.400
3.486 000
411
Unmcnured items
%
10
10
W
345.431
2 917,526
3,262.957
Subtotal
3.799.746          32.092,7*2           35.802,027
5.0 DIVERSION WATERWAYS No.2
5.1                J Diversion Intake Gales
each             1              2,400 00 1            9.600.00 1          12.00000 [         —                 21,600 |
86,400 |
108.000 |
Subtotal
21.600
86,400
108.000
6.0
TRANSMISSION LINES
I''’
l«a
1
| SC 230-RV Trans Line from P.P f 1 to P P 12
I km
1
35,000 00 ]
140.000 00 T
175.000.00 1
15 1        525,000 I
2.100.000 1
2.625,000 1
|SC 230 kV Trent Line from P P 11 |g Glgel Gibe
[km
j
35.000 00 [
140.00000 (
175,000 00 ]
165 |   5,775,000 |
23.100,000 |
28.675.000 J
8,300.000
2B.2O0.MO
31,800,000DRAWINGS
FOR
GEBA HYDROELECTRIC PROJECTDrawing
GE-1
GE-2
GE-3
GE-4
GE-5
GE-6
GE-7
GE-8
GE-9
GE-10
GE-11
GE-12
LIST OF DRAWINGS
Title
Project Plan
Project Profile
Reserv oir Plan
Gcba Dam - Plan
Geba Dam - Profiles
Geba Dam - Cross-Section and Power Outlet
Geba Dam - Spillway Profile and Section
Power Diversions - Plans
Power Diversions - Intakes
Power  Diversions  -  Canal  Section  and  Penstock. Powerhouse No 1 - Plan and Section
Powerhouse No 2 - Plan and Section* Metu ■           \
P4*C — - --A A
' pow  '      erhouse &>■ 2
- -Hnd^r
< -_- Penstock “            )
Power Canal
<nr • *'
i i                J/ s .
/---- Powerhouse No. 1 l0/tJll
ia»i <bny ro«itr
Penstock —y
KOJUBO \
PROJECT LOCATION MAP
01
I
200      400km !1
Diversion Dam
and Intake No. 1
SCALE
/ cN \
MINISTRY OF WATER RESOURCES
ADOS A0A0A ETHIOPIA
TAMS - ULG
NEW YORK - LONDON - ADOS ABABA
L- R^rvcirihor^-
L--~ :—:—:
BARO-AKOeO MASTER PLAN PREFEASIBILITY STUDIES
GEBA HYDROELECTRIC POWER PROJECT
PROJECT PLAN
Dote October ’.996^
| Dwg No GE -
SCA|_£ W KILOMETERM-FVATION IN MFTFRS
D ,S'ANCt * <HOM£'ERS
MINISTRY OF WATER RESOURCES
AOOIS ABABA ETH!O»AGfrHA romr
___________
ministry of water resources
ADOS ABABA ETHIOPIA
TAMS - ULG
MEW VOPK - LONOON - ADOS ABABA
baro-akobo master plan prefeasibiljty studies
5EBA HYDROGJECTRlC POWER PROJECT RESERVOIR PLAN
Dote;
| Dwg No GE-3•70000
L
Stilling Basin
I
I
MINISTRY OF WATER RESOURCES
"
±PPJ?  ff OA____ ETHIOPIA___________
AA
TAMS - UL6
P>t<:_ October W
0*9 GE - 4PROFILE ONINTAKE AND DIVERSION TUNNEL
(Spillway Crest El. 2170.0
PROFILE ON SPILLWAY CHUTE
ministry of water resources
*20IS AjAjA fTWtOeiA
TAMS - ULG
T»X - LCXX- - ADO1S Al AJA
baro-akobo master plan prefeasibility studies
GEBa hydroelectric power project
GEBA DAM - PROFILES
X      Octoo-er TM                                 Dvg *         « - 5i
I Dan
Normal Haim I mum Water Level
EL 2170 ----------------- 7
Crest EL 2175.00
Coaree
,l Minimum r level JUS
Tran?jIionLllm thIck
Pilfer2.0 m thick
Select Earth fill upstreae Shell
6 ,r'z' Cort Trench
sEarfh-flu
Stripping
ELEVATION A - A
MINISTRY OF WATER RESOURCES
__________________________<0015 AS AAA ETHIOPIA
t TAMS - ULG
__________________><W TOK - LOOCM . AQOIS ABAfl*______________________ 3AR0-AK0BQ MASTER PLAN PREFEASIBILITY STUDIES
GEBA HYDROELECTRIC POWER PROJECT 0AM CROSS - SECTION ANO POWER OUTLET
[ DaU :                                                  | Cvt »•
-6Ministry of water resources.
ADDIS A9ABA ETHIOPIA
TAMS - ULG
YORK - LONDON - ADDlS ABABA
baro-akcbo master plan prefeasibility studies
GEBA HYDROELECTRIC POWER PROJECT
SPILLWAY PROFILE ANO SECTIONS
D»t« :             Odrtef
1 Dwg No GE - 7I
N
jversion Dam
ind 'nfake No. 2
€l. 1680
1
Sc«lc 1 so,wo
I
MINISTRY OF WATER RESOURCES
--------------------- AQQtS ABABA________________ ETHIOPIA_____________________________
TAMS - ULG
t J3.0C
---------------------- gWYMK ■ lONOOM - AflDlS ABABA____________________________________
BAR0-AKQ9Q MASTER PLAN PREFEASIBILITY STUDIES
GE9A HYDROELECTRIC POWER PROJECT POWER DIVERSIONS - PLANS.
°»te :             Octobe* W
I °*9 *° GE - 8Scale WOOO
Intake
Structure
Spillway
Diversion Sluiceway
ELEVATION
UPSTREAM ELEVATION OF SPILLWAY
AND INTAKE STRUCSTcaUleR1:E200
MINISTRY OF WATER RESOURCES
________________________A DO IS ABABA ETHIOPIA_______________________________________
TAMS - ULG
_______<U YQPK - LOWOOW - ADO IS ABABA_________________________________________
SARO-AKQBQ master PLAN PREFEASIBILITY STUDIES geba hydroelectric power project
POWER DIVERSIONS - INTAKES
O»»e :            October ^4
\ Qwg No 5E - 9Existing Ground
__Surface .
Headrace Canal
tUl
I Penstock
Assigned Rode
__ Surface
Powerhouse
T.V.a. 184 0.0
I Geba River I
.15 Canal lining ttypJ
Canal
GEBA 1 PENSTOCK AND POWERHOUSE PROFILE
Existing Ground
POWER CANAL TYPICAL    SECTION    IN    VERY STEEPLY SLOPING TERRAIN
Headrace Canal
Assumed Rock
J. Penstock
C Canal Lining
-txist ing Ground Surf a ce
^•Henhouse
El. 1500.C
(6eba R i ver ‘
POWER CANAL TYPICAL SECTION IN LESS STEEPLY SLOPING TERRAIN
MINISTRY OF WATER RESOURCES
_____________ADC IS ABABA ETHIOPIA___________________
TAMS - ULG
«v Y0«*           - LOHOOM - ADO IS ABABA
^-LPENSTOCK AND POWERHOUSE PROFILE
BARO-akqbq MASTER PLAN PREFEASIBILITY STUDIES GEBA HYDROELECTRIC POWER PROJECT
POWER DIVERSIONS - CANAL SECTION ANO PENSTOCKS
[ Ovg W GE -10BARQ-AKCaO MASTER PLAN PREFEASlBlIJTY STUDIES
CEBA HYDROELECTRIC POWER PROJECT POWERHOUSE NO J - PLAN ANO SECTION
D °te- October 1996
Dwg No GE — 118.00x10.00
Service Boy
p
’rsnsfomw '
Burried Manifold
3 20m D;o
Surface Penstock
Drott Tube Dec* £ 24MW Generator (Typ.)
~iT    Li—lT                Lr—i
£ 24MW Unit
Transformer Bay
Bockfill
Generator Floor
'
m
i
t Intake Valve
t Distributor
ministry of water resources
ADCMS ABABA ETHIOPIA
TAMS - ULG
HEW fCPK - LONDON - ADOS ABABA
BARO-AKOBO master plan prefeasibility studies
Dote. October 199611^APPENDIX 3-1
GUMERO HYDROELECTRIC PROJECT Detailed Cost Estimates7
baroakobo    project Integrated Master Plan
GUMERO HYDROELECTRIC Pro -
PREFEASIBILIrr study ECT '
COST ESTIMATE
““ Re‘- L*^: E'
DESCRIPTION
A: CIVIL WORKS
DAMS AND APPURTENANT WORKS
POWER PLANT No.1
DIVERSION WATERWAYS No.1
POWER PLANT No.2
DIVERSION WATERWAYS No.2
POWER PLANT No.3
DIVERSION WATERWAYS No 3
D«n Type:             Rocllv.
In«t Capacity: 12JMW. 1«.4MW^
Local
4,356,819
577.281
728.329
621,614
548.395
717.405
1.484.226
’7.427.274
2   309.123
2.913.316
2.486.457
2.193.561
2.869,621
5.936.906
TOTAL CIVIL WORKS
B: ELECTRO-MECHANICAL EQUIPMENT DAMS AND APPURTENANT WORKS
POWER PLANT No.1
DIVERSION WATERWAYS No.1
POWER PLANT No.2
DIVERSION WATERWAYS No.2
POWER PLANT No.3
DIVERSION WATERWAYS No.3
TRANSMISSION LINES
TOTAL EQUIPMENT
TOTAL BASIC COST
Physical Contingencies Engineering and Administration
TOTAL CONSTRUCTION COST
9,034,069        3«,136,271
20%
10%
52.400
1.374,144
1.600
1,798,559
1,600
1,969,537
1,600
884.520
6,083,960
15,118,030
3,023,606
1.814,164
19,955,799
209.600
5.496.577
6.400
7.194,236
6.400
7.878,147
6.400
3.538.M0
12,094.424
7.2M.M4TAMS ConsultarvlK, Inc.
H-Dw-K
GUMERO hydroelectric project
PREFEASIBILITY STUDY
COST ESTIMATE
EL
DwnTjrp^:           RocKfiK
fort Cipiaty: 12JMW, 1S.4MW & 21MW
CcdLwl:
Amount
Local
Jan-96
Total
preJb™narieS
^jcess Roads
pjverson Tunnel
Coffwiani
Rddtflll Dam Spilway (separate from dam)
Lffrtbievei Outlet
TOTAL 1.0
F    POWER PLANT No.1 1     Preliminaries
2
3
4
5
6
7
Access Reads
Power l make Penstock (surface) Powerhouse (surface) Tailrace Channel Switchyard
t                Reads
; jMeiSOn Intake
Canal
1
I
l       ?-“s 3
5 S
r
TOTAL 3.0
I
<
^carial
TOTAL 5.0
653.523
79.094
429.760
194.175
2,322.931
651.141
26.194
4,356,819
06.592
150.278
42.178
45.104
207.879
0
45,249
677,281
109.249
0
59.563
559,516
728,329
93.242
185.079
42,178
43.397
207,468
0
45,249
621.614
62.259
0
59.563
406,573
548.395
2,614,091
316,375
1.719.041
776.701
9291,726
2.604.563
104,777
17,427,274
346,369
601,112
168,714
160,415
831,518
0
160,996
2,309,123
436,997
0
238,253
2.238,065
2,913,316
372.969
740,317
168,714
193,589
829,672
0
180,996
2.486,457
329.037
0
238.253
1.626.290
2,193,581
3.267.614
395.469
2,148.802
970.876
11,614.657
3,255,704
130.972
21J84,O93
432.961
751,390
210,892
225,519
1.039,397
0
226,245 2,886,404
548,247
0
297h817 2,797,581 3,641,645
466.211
925,396
210,692
241,987
1,037.340
0
226 245 3,108,071
411,296
0
297.817
2.032.863
2,741,976BARO-AKOBO project Integrated Master Plan
gumero hydroelectric project
PREFEASIBILITY STUDY COST ESTIMATE
Max. Res. Level: El. 1.610
Inst. Capacity:
Dam Type: Rockfii
12.2 MW, 1MMW &21MW
Item
No.
description
Local
Foreign" 1—
6.0
6.1
6.2
6.3
6.4
6.5
6.6
6.7
POWER PLANT No.3
Preliminaries
Access Roads
Power Intake
Penstock (surface)
Powerhouse (surface)
Tailrace Channel
Switchyard
107.611 308.465
42.178
48.397
173.501
0
37.252
430.443 1,233,862
168.714 I 193.589 I
694,006
0
149.007
%
•4|
«l
TOTAL 6.0
717,405
2,869,621
if
7.0
7.1
7.2
7.3
7.4
DIVERSION WATERWAYS No.3
Preliminaries
Access Roads
Diversion Intake
Diversion Canal
222.634
0
80,501 1.181,091
890.536
0
322,004 4.724.366
1,1
c
jv
--------------------------------------------------------- TOTAL 7.0
1,484,226
5,936,906TAMS ConttJkM*. Inc,
81-Dtc«
GUMERO hydroelectric project PREFEASIBILITY STUDY
COST ESTIMATE
Max. R«-L*vel: EL 1,61« Dam Type:                      Rotkfil InstCapaoty:                    1I4MW & 21MW
Coil Level:
Local
Amount
Foreign^
^^^MECHANICAL EQUIPMENT -BTiRDASuSTENAST WORKS
■0
>1
•2
11
o AWb mi
d anl
p0 7f^Uad Gales - Low Level Outlet
^ Pressure Slide Gates - Low Level Outlet
TOTAL 1.0
powerplant MoJ
Power Intake Gates
Penstock
intet Valves
Turbines, Governors and Turbine Auxiliary Equipment Generators and Generator Auxiliary Equipment Powerhouse Crane
Station Auxiliary Mechanical Equipment Station Auxiliary Electrical Equipment
Main Transformers
Swhyard Equipment Unmeasured Items
10.000
3.200
39.200
52.400           209,600
50.000
16.000
196,000
262,000
11 2i £3 2* 25 25 IT 15 ii
:io :ii
1.0
11 U'VKKSIIOniMakWa AcaIE1eRs WAVS Mo.,
111
Q
<4
Turbine^ Qq
V374J44
5,496,577
1.600               6.400
TOTAL 3.0
1,600
1,600
136,454
52,000
294.000
6,870721
8,000
8,000
8,000
842,270
260.000
<8
<?
<S
’ID
Ml
p!"®r,,Or’ and GeX,3™ T“rt>ine Auxiliary Equipment
tJXiUar¥ EQuipmen1
5O3.OD0
45.000
6,400
6,400
673.816
208.000
1.176,000
2.032.000
SS *"S? S"?' ^Pment
Equipment
TOTAL 4.0
TOTAL 5.0
73,000
261.000
112,000
120.000
163,505
1.798,559
1.600
1 600
P
180.000
292,000
1,044.000
448.000
480.000
554.022
7.194,238
6,400
6,400
1,470.000
2.540.000
225.000
365.000
1,305.000
560.000
600,000
817.527
8,992.797
8.000
8,000BARO-AKOeO PROJECT
Integrated Master Plan
tami
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Mat Res. Level; El. 1,«10 Dam Type:                                Rockfill
lost. Capacity: 12.2MW. 1I 4MW1 21MW
CostLey^
6.10
6.11
DESCRIPTION_______________________________________ 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
TOTAL 6.0
DIVERSION WATERWAYS No.3
Local
1,600
173,888
56,000
334.000
552,000
45,000
75,000
300,000
128,000
125,000
179,049
Amount
Foreign
6.400
695,552
224,000
1.336.000
2,208.000
180.000
300.000
1,200,000
512.000
500,000
716.195
1,969,537           7,876,147      9,1471
Diversion Intake Gates
1,600
6.400
TOTAL 7.0
1,600
6,400
1
TRANSMISSION UNES
Transmission Line 132-kV from Gumero No.1 to Gambeta-Gore
Transmission Line 132-kV from Gumero No 2 to Gumero No.1
294.840
189,540
400,140
1,179.360
758.160
1.600,560
1A
K,
Transmission Line 132-kV from Gumero No 3 to Gumero No 2
TOTAL 8.0
884,520
3,538,080
442GUMfiRO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
cost estimate
Mu. R«*. Lfwh El.
/
/
/
Dam T«m: RocVIHI
12.2MW 114MW & 21 MW
Co* Laul-
T
I
Unll Plica*
I                            Amount
\
fitrnf
/Ho.
iDESCRtPTKW
1 UnM*
Local
USS
Foialgn
USS
Total
USS
1   Local      \      PWMQTt    I        Total        \ Quinbtta*        1 USS           1       USS          1       USS         \
/l!
ff. ELECTRO-MECHANICAL EQUIPMENT
£0             POWER PLANT No.3
__
/ Power Intake Galea
each
000.00
3,200 00
4,00000
2
1.500 1                6.400
8.0OT1
IPensiock
T
494 00
1.976 00
2.470 00
352
173 088
695 552
669 440
63                   IlnteiVateM
each
20 000 00
112 000 00
140 000.00
2
56,000
224000
260,000
64
I Turbines. Governors and Turbine Auxiliary Equipment
each
167,000 00
660.000 00
835,000 00
2
334 000
1.336,000
1 670.DO0
[6.5
Generalors and Generator Auidliary Equipment
each
276 000 00
1,104,000.00
1,380,000 00
2
552 000
2.208,000
2760,000
6.6
Powerhouse Crane
LS
45,000 00
180,000.00
225 000 00
1
45,000
180,000
225 000
67
Station AwdUuy Mechanical Equipment
LS.
75.000 00
300 000.00
375.000 00
1
75 000
300 000
375.000
68
Station AunMery Electrical Equipment
LS
300,000 00
1,200,000.00
1 50000000
1
300 000
1 200.000
1,500,000
6.9
Man Transformer &
each
64,000 00
256 000.00
320 000 00
2
128.000
512,000
640,000
6 10
Switchyard Equipment
LS
125 000 00
500 000.00
625,000.00
1
125,000
500,000
625.000
[6.11
Unmeasured llema
j
Subtotal
%
10
10
kl
179 040               716.195              895 244
1W3/
7,178.147           6,847,464
7.0
DIVERSION WATERWAYS No.3
El
| Diverwon Intake Galea
|cb£A
000,00 t
3 200 00 |
4,000 00 [
2 [ I goFT
ooo
f     a     ooo     |
Subtotal
14100
6.400
1.000BARO-AKOBO PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Max. Res. Level: El. 1,110                      Dam Type: RockflO
TAMS Consultants, Inc.
01-Dec-86
Inst. Capacity: 112MW, 18.4MW A 21MW Cost Level:                                                       Jan-86
Unit Prices
Amount
Item
No.
DESCRIPTION
Units
Local
USS
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
1.0 DAMS AND APPURTENANT WORKS
1.1 Preliminaries
1.1.1
Mobilization
%
15.00
1500
15 00
653,523
2614.091
3,267.614
1.12
Land acquisition
ha
2,259 62
0.00
2 259 82
0
0
0
0
1.1.3
SHe 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
39 548 85
10
79.094
316,375
395,469
122
New Road
km
17 400 61
69 602 46
87 003.07
0
0
0
0
123
Stream Crossing
No
22,598 20
90.392 80
112.991.00
0
0
0
0
Subtotal
79,094
316,375
395.469
1.3 Diversion Tunnel
1.31
Portal excavation
cum
1 36
542
6.78
2.000
2.712
10848
13,560
1.3 2
Tunnel excavation
cu m
1017
40 68
50 65
7.950
80.652
323,406
404 258
1.3 3
Tunnel support • rock bolls
T
1,355 89
5 423 57
6 779 46
20
27660
110.641
138.301
1.3.4
Tunnel support • shotcrete
sq.m
5 65
2260
28 25
690
3,896
15,594
19.493
1.3.5
Tunnel support - arches and ribs
T
451 96
1.807 66
2 259 82
0
0
0
0
136
Concrete lining
cu m
40 88
162 70
203 38
2450
99 656
398 625
498.281
h 37
Structural concrete
cum
25 99
103 95
129 94
0
0
0
°J
H.3B
Formwork
m
ID 17
40 68
50 85
5,500
M.935
223,740 1                279 675 /
T
248 58
994 32
1 242 90
319
79 297
317 168 /
396.485 /
\O«WWuj lor tjitxAinq sort
m
1B f»2
83 77
70 00
32 031
17R 126 /                lOO 157 /
\ A "A A '
M2
«S1 07
oo
74 r
x  ' aat*— \-j,
\"w
•» oo
n im.
n oq
!OO OT5 /
70. *’■' i
Hiasv /              fuj_                 /
7 30 -W /GUMERO HYDROELECTRIC PROJECT
PReFEASIBfUTY STUDY
COST ESTIMATE
an-
Mia.Reo. LraltEI. Mil
Own Type:      Roc*flII
/—7-----------------------
lnrt,C«p*cHy; U.2MW , 1B .4MW 4 21MW
Cort Lavri; Jan ^4
Unll Price*
Amount
\
Ln /
INq jdescrjptkw
Unite
' Local
USS
Foreign
ust
Total
US|
Quarvtiliea
Local
ust
Foreign i         Total          I
US 4
A: CiViL WORKS
1.4 Cattenlm
/f.4 1 I Foundation excavation - Common
cujn
0.72
290
3.02
26,700
19,331
77,323
96.654 i
1.42       [Foundation axcavabon • Rock
cu m
1 81
723
9.04
0
0
0
143          Garrow excayaWan - Earth
cu.m
DM
2 71
3.39
132,200
89^2
358,526
448.158
1.44
Borrow excavation - Rock
cum
0 96
384
4 80
7000
6720
26.800
33,600
1 45
Hauling tiff material (over 2 km)
cu m/km
010
041
0 51
0
0
0
0
1 46
Unprocessed fill (placement)
cum
0 45
1 81
226
132,200
59 754
239018
298 772
1.4 7
Piocaaaed Ml (piacemenl)
cum
1.36
542
6 70
7000
a.«2
37 wa
47,460
1.4.6
Unmeasured Hems
%
500
500
5 00
9246
36 9B6
48.232
SuMcHal
194,175
77«r70l
970.67B
14             Rockfill Dot
1 51
Foundation excavtlbon * Common
cUm
072
290
3 82
221,580
160 424
641 696
002,120
1.5.2
Foundation e®cavatlon - Rock
CU m
1 01
723
904
45.580
82,409
329 835
412 043
1.53
Bwiow axcavalbon - Eadt
cu.m
068
2 71
3.39
0
0
0
0
1 5.4
Borrow •fccavaiion - Rock
cum
09A
3 84
4 80
470,100
468.978
1,835,904
2 294 680
155
Haufeng fill mater lai {ewer 2 km)
cu m/km
0.10
0.41
0 51
a
0
0
a
156
Impervious cor•
cum
2 25
004
11.30
202,390
487 401
1,629 600
2,287.007
1,5.7
Rockfiil (placement)
turn
0 68
2 71
3 39
488 330
331 088
1.324,351
1.856 439
1 56
Filin
cu m
3 39
1358
16 95
21 980
74,444
297.770
□77 222
1.5.9
Dra>ns, tramiliona
cum
3 39
13 58
1895
135,030
457 752
1,831,007
2.288,759
1 5.10
Rip-rap l placamanl)
cum
1.13
4 52
5 65
25 590
28.917
115667
144 584
JS.11
Drilling lor grouting and dralm
m
11.30
45 20
56 50
5,720
64,636
258 544
323 180
1 5 12
Grouting
T
112.09
451 97
564 90
857
S8 2fi9
385,077
481 346
1513
Unmeasured Item*
%
500
5.00
500
110 616 |               442463
553,079 '
SUttOCit
2,322,931             9.291,720 B .514,657BARO-AKOBO PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Concultantc, Inc.
01-Dec-M
1.810
Dim Type: RockflN
Unit Prices
Amount
Item
No.
DESCRIPTION
Units
Local
USS
Foreign
USS
Total
USS
Quantities
Local Foreign Total
USS USS USS
le
1.< Spillway (separate from dem)
1.6.1
Bulk excavation - Common
cum
0 72
290
362
180.000
130 320
521,280
651,600
162
Bulk excavation - Rock
cum
181
723
904
80 400
145 363
581.453
726.816
1.6.3
Structural excavallon- Rock
cu.m
452
1808
2260
0
0
0
0
1 6.4
Mass concrete
cu.m
18.06
72.31
90 39
12,555
226,969
907.877
1.134 846
165
Structural concrete
cum
25 99
103 95
129 94
510
13,254
53.016
66,269
1.6.6
Formwork
sqm
10.17
40 66
5085
7430
75.563
302 252
377.816
1.6.7
Steel 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
13 560
54.240
67,800
1.6.9
Drilling for grouting and dtams(from gall)
m
15 82
63.27
7909
40
633
2.531
3,164
1.6.10
Anchors (including drilling and Grouting)
m
2,982 96
11 931 85
14,914 81
22
6.563
26.250
32,613
1.611
Grouting
T
112 99
451 97
564 96
4
452
1 808
2.260
1 6.12
Unmeasured items
%
500
500
500
31.007
124,027
155,034
Subtotal
651.141           2.604,563           3.255.704
1.7 Low-le 1 7.1
vel Outlet
Portal excavation
cu m
1 36
542
678
0
0
0
01
172
. 173
Tunnel excavation
cu m
1017
4068
50 85
0
0
0
ol
.
1.7 4
Shaft excavation
cum
1808
72 31
90.39
0
0
0
0/
1
1 Tunnel tuooort - rock boMs
T
1 355 89
5 423 57
6.779 46
0
0
0|
*q rr
565
22 60
28 25
0
0
0/
01
0
T
451 96
1 807 86
2.259 82
0
0
o/                      01
\1 7 7
\\ 7 B
\l             cone aU
\%trur.tu«wl corujeU
cu m
I cu m
40 BB
».99
162 TO
103 05
203 36
129 IM
0
261
01 9 523 7
oI
29 Off 2 I
32.615  7 SI f<M /
Q
1
\ \ 7                       yr ».< »v»
___ VlailTm■w'lr.wrr --n*
IO 17
2 40 nn
tllR!-
W----------------
40 M
----------- W.liL -----------
so n-i
____ 1 _7«? M«>
______
1.005
39
Si
MJOJ f
oI
jjwi • /
a/
■*».ors /
ftRO
HYDROELECTRIC
PROJECT
■w-% w,
PREFEASIBILITY STUDY COST ESTIMATE
MW
Inst. C
Dm> Type:        RockMl
1B.4MW A 11MW
;
Cort Level:
Unit Price a
ftnwurrt
\
jWem /
/■uta. /oESCH/priorM
I
| Un#i
Local
1      US4
Foreign
USI
Total
US 1
Quantkhea ,
Lo«4 1 Foreign I Total \
us > | US | \ usi \
A: CIVIL WORKS
2.0 POWER PLANT No.1
2.1            PrdknlnarAtr
/2fJ iMottbiation
LS
15.00
1500
1500
85.592
346.369 1            432.981
[2.1 2 /Land KQUrsibon
hi
2,250.02
0.00
2,25962
0
0
0
|2.13 |SlecJ«irarK*
M
1,694 87
6,779 46
8,474 33
0
0
01                 0
Subtotal
66.592               346 369
432961
2.2            Accaaa Roarf*
2 21
Road Improvement
km
7 909 37
31 637.46
39,546 85
8
63 275
253,100
318 375
2 22
New Road
tan
17.400.61
69602 46
87.00307
5
87 003
346 012
435015
22 3
Stream Cresting
No
22.590 20
90 302.00
112.991,00
0
0
0
0
Subtotal
150.278
601.112
7S1.39O
2.1            Power Intake
23 1
Earth excavation
cu m
072
290
362
110
80
319
398
232
Rock excavation
cum
1 8)
7 23
9 04
0
0
0
0
233
Lining c»DC/t<»
cum
40 68
162 70                203 38
0
0
0
0
2.3 4
Structural ooncieia
cum
25 99
103 95
129 94
450
11 695
46.776
58 473
' 2-3.5
Formwork
sq m
10.17
40.66
5065
1,350
13 730
54 918
68 648
XI.8
Steal reinforcement
I
240.58
994 32
1.242 90
59
14666
56 665
73 331
2 3.7
Unmaaaurtd llcmt
%
500
5 00
500
2 008
6 034
10 042
Subtotal
42.178
150,714               21O.8&2
2.4
Pentlock (auriace)
241
.
2 42
Common excavation
cum
0 72
2.00
362
2 400
1.738
6,950
8.688
Rock axcavatton-
cu.m
1 at
723
904
250
452
1.608
2260
24 3
Anchor boM&
m
13 56
54 23
67 79
0
0
0
0
244
Mm concrete
cu.m
10 D8
72.31
90 30
250
4520
1B.078
22 5M
24 5
Structural concrale
cu.m
25.es
103 95
129.94
260
6.407
25.960
32 485
246
Formwork
iq.rn
10.17
40 56
50 65
2,000
20 340
81 360
101700
247
Steel retnfcrcamenl
T
248 58
994 32
1.242 90
30
7 457
29 830
37,267
24 5
Unmaawred Item*
%
1000
1000
10 00
4 100
16 401
20,502
iJW
180.4158ARO-AKO6O PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultants, Inc.
01-Dec-9 fl
Max. Ret. Level: El. 1,810
Inst Capacity: 12 J MW, 18.4MW & 21MW
Dam Type: Rockflll
Cort Level:               Jan-9fl
UnH Prices
Amount
Item
No.
DESCRIPTION
Unite
Local
USS
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign
US S
Total
USS
A: CIVIL WORKS
2.5 Powerhouse (surface)
251
Common excavation
cu.m
072
290
362
6300
4.561
16.245
22.806
2.5.2
Rock excavation
cum
1.81
7.23
904
4.780
8 642
34.569
43,211
2 53
Earthfil
cu.m
045
1.81
226
3900
1.763
7.061
8814
25.4
Mass concrete
cu.m
1808
72 31
90 39
1 036
18729
74,915
93,644
2.5.5
Structural concrete
cum
2599
103 95
129 94
976
25 364
101,457
126 821
256
Formwork
sqm
10.17
40 68
5085
2,990
30.408
121633
152,042
257
Sleet reinforcement
T
248 58
994 32
1,242.90
196
49.219
196.875
246.094
258
Roofing
sqm
180.79
723.14
903 93
162
29 287
117149
146,437
259
Qlrt r- in a ititL
DKJCKWOtK
sq m
904
36.16
45 20
324
2.929
11,716
14645
2.5.10
Miscellaneous Metalwork
T
72314
2 892 57
3615.71
25
18.079
72.314
90 393
2511
Slope Protection
sq m
452
1808
2260
0
0
0
0
I2.5.12
Unmeasured Rems
%
1000
10.00
1000
18 898
75.593
94.491
Subtotal
207.879
831.516              1.039.397
2.6 Tailrace Channel
I2.6.I
Common excavation
cu m
072
290
362
0
0
0
0
12.62
Rock excavation
cum
1 81
723
904
0
0
0
0
\2.6.3        ^Unmeasured Rems
%
500
500
500
0
0
0
Subtotal                                                                                                                                                                   0                                                 0                            0
1.7             Switchyard
\c<xnmon lucrYiGoc
|cu m
0 72
290
362
8,100
5,864 |                 23 458 /                 29 322 /
yi.7 7        \Rock
tcu m
1 Bl
7 21
904
0
\7 •»
Isq m
124 2©
407 10
021 40
720
0t
______ __
I VOO 379 I rjo./fo /
0/
•
7 34
5 400
7,0^/ 1                    3t.m J
/
•              X ‘ • r, vat ■
.s
ID <**
S 4P
1U <MJ
ia 00
4.9 94 IGCr/VTEFTO HYDROELECTRIC F’FCOJECT
PREFEASIBILITY STUDY
COST ESTIMATE
M1I
Dam Type:          RocklM
Jen-84
fNOr /Pj
g7
<JnN Price*
1 Locef
OEScfflprroN______________________ _
USS
Foreign
LlSt
Ttrial
US 1
Quamillei
Local
US 4
Cod Lave*.
Amount
Foreign
US »
Tout
US 4
J
xo
Ar CIVIL WORKS
DIVERSION WATERWAYS NoJ
p.1.1
MoUffsalton
L.S
15.00
15.00
1500
109 249
+36 997
546 247
3.t 2
Land acquisition
ha
2,259.82
000
2,259 02
□
0
0
0
bi3
Site ckifflnce
ha
1.694 67
6779 46
6474.33
0
0
0
0
3.2.1
Roed imprCremer!
km
7,909 37
31,637 46
39546 65
0
0
0
0
32 4
New Road
km
17,40061
69,602 46
67 003 07
0
0
0
0
325
Stream Crossing
No
22 .590 20
90,392 00
112 991 00
0
0
0
0
Sublet*!                                                                                                                                                                             0                              0                               0
33              Dive**ion Intake
13 3.’         I E aclh vsk ■vetHXi
cu.m
0.72
2 90
362
503
364
1.457
1,021 1
133.2         | Rock excawetofi
cu m
1.81
7 23
0 04
393
711
2 842
3,553 1
13.3.3        | Mass concrete
cu m
16.06
72 31
90 39
786
14 209
56,837
71,047 1
1334
Structural concrete
cum
25 99
103 95
129.94
450
1 1.605
46 770
SO 473 I
1335
Forrmwrk
sq m
10 17
40 60
50 65
1,483
15 062
60 320
75,411
13.3,6
Steel relnlafcement
T
240 sa
994 32
1.242 90
50
14 666
58 665
73.331
13.3.7        | Unmeasured item*
M
5 00
5 00
5.00
2 836 |                 11,345
14,182
Sutrtolal
50,563
238,253
29Z.817BARO-AKOBO PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultants, Inc.
01-Dec-9 6
Max. Res. Level: El. 1,810
Dam Type:         Rockfill
Inst. Capacity: 12.2MW, 18.4MW4 21MW Cost Level:                                                                                                  Jan-38
Unit Prices
Amount
Item
No.
DESCRIPTION
Units
Local
USS
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
3.4 Diversion Canal
341           Common excavation
cu.m
0.72
2.90
3.62
18 200
13,177
52.707
65 884
3 42         | Rock excavation
cum
1 81
7 23
904
167 700
303 202
1.212 806
1 516008
3 43        | Earth fill from borrow
cu m
1 36
542
6 78
0
0
0
0
34.4        | Hauling Gil material
cu.m/km
0.10
041
051
0
0
0
0
3 45        [Earth Gil
cu.m
0.45
1 81
226
0
0
0
0
3 46        [Lining concrete
cum
33 90
135 59
169 49
5030
170 507
682,028
852 535
34.7        | Structural concrete
cu.m
25 99
103 95
129 94
0
0
0
0
13.4.8       | Formwork
sqm
10 17
40 68
50 85
0
0
0
0
13.4.9       | Steel reinforcement
T
248 58
994 32
1 242 90
185
45 987
183.949
229 937
|34 10     [Unmeasured items
%
500
500
500
Subtotal
26.644 |              106575               133 218
559.516 2.238.065 2.797.581GUMBFtO HYDROELECTRIC PROJECT PREFEASfBILITY STUDY
COST ESTIMATE
4.0 POWER PLANT No.2
4.1 FVefonlnartes
/4.1J         1 Habitation
h$
15.00
15 00
1500
84 894
339 577
41 2
| Land acquisition
424 471
—
2259.82 |
0.00
2 259 82
0
0
0
0
|4 13
1 Site clearance
1 694.87 1
6 779 46
6 474 33
0
0
0
0
H«M 339,577
424.471
4.2 Access Roads
42 1
RmO Improvemenl
km
7,90937
31,637 48
39.54685
8
63,275
253 100
316.375
422
New Road
km
17,400 61
69,602 46
57.003.07
7
121.804
487.217
609.021
4 23
Slream Crossing
No
22 598 20
90 392.80
112.991 00
0
0
0
0
Subtotal
1155,078             740.317
925,398
4,J______ Power Intake
4.3 1
Eenn excaraltec
cu.m
072
290
3 62
110
MO
319                      396
4 3.2
Rock excavation
cu.m
1 61
723
9.04
0
0
43 3
Lining concrete
cum
40 88
162 70
203 38
0
0
0  r—r
0
0
43 4
Slructur al concrete
cu m
25 99
103.05
129.94
450
11,696
46,778
58473
43 5
Formwork
tqm
1017
40.68
50 65
1 350
13 730
54.918
58.648
436
Sleel rerilo< cement
I
246 56
994 32
1242 90
59
14,666
58.665
73 331
43 7
Unmeuixed items
%
500
SOO
5.00
2,000
8.034
10 042
Subtotal
42.176
I68.7M               210,892
4/4              Pentlock leurfacel
441
Common excavation
cum
072
2 90
362
2.400
1 738
6 950
8688
4 42
Rock excavation
cu.m
1.81
7 23
0 04
250
452
1 808
7.260
44 3
Anchor bolts
m
13 56
4.4 4
44 5
Maw   concrete
Structural concrete
cu.m
cu.m
54 23
72 31
67 70
90 39
0 500
0 9O39
0 36 158
0 45 195
25.90
F ormwofk
Steel relrforcemenf
eq m
T
IV,1* : 248 58
10395
Jrt fin
129 94
SDfl1!
0 ?onr]
446 447
0 20 340
0 81 360
0 101 700
B
99432
1 242 90
50
12429
49,716
62 145
446
i tameanued lent
*
1000 |               1000
1000
4,400
17,599
21 999
Subtotal
48,397                193.589               241.987BARO-AKOBO PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Dam Type:        Rockfill
Inst. Cspacify: 12.2MW. 18.4MWA 21MW
TAMS Consultants, Inc.
01-Dec-H
CostLtv.l:             J»n4M
Unit Prices
Amount
litem
[No.
DESCRIPTION
Units
Local
USS
Foreign
USI
Total
USI
Local                 Foreign                 Total
Quantities
USI                      USI
USI
4.6
A: CIVIL WORKS
Powerhouse (surface)
45.1
Common excavation
cu.m
0.72
290
3.62
7,800
5,647
22 589
28.236
45 2
Rock excavation
cu.m
181
7.23
904
4,230
7.648
X.591
38,239
4.5.3
Earth fill
cu.m
045
1.81
226
2,870
1,297
5.189
6.486
4.5.4
Mass concrete
cu.m
1806
72.31
90.39
1,036
18,729
74,915
93.844
455
Structural concrete
cu.m
25 99
10395
129.94
976
25.364
101.457
126 821
455
Formwork
sqm
1017
40 68
5085
2.990
30,408
121.633
152.042
45.7
Steel reinforcement
T
248 58
994 32
1.242 90
198
49 219
196,875
246094
4.5.8
Roofing
sq m
180 79
72314
903 93
162
29 287
117,149
146 437
45.9
Blockwork
sqm
9.04
3616
45.20
324
2 929
11,716
14645
4510
Miscellaneous Metalwork
T
723 14
2.892.57
3.615.71
25
16,079
72.314
90393
4 5.11
Slope Proteclion
sq.m
452
1806
2260
0
0
0
0
4.5.12
Unmeasured Items
%
1000
10.00
1000
18.861
75.443
94 304
Subtotal
207,468               829,872            1,037,340
4.6             TaHrace Channel
cu m
0 72
290
362
0
0
01
cu m
1 81
723
904
0
0
\4 S 3        | Unmeasured Kams
%
500
500
500
0
n
0 1 °J ------------------s
00
------------------
°1
_____1GUMERO HYDROELECTRIC PROJECT
PREFEASIBiLITY STUDY
COST ESTIMATE
i.fi»
biaf, C
Dan Typer RocfcflM
1------ 1             UnN Prices
Amount
1
Idescriftkn
>4; C/WL WORKS
5.0 DIVERSION WATERWAYS No. 2
f.f Preflmtoartea
| Units
| Local
L ** J
u
Foreign Total
USS                 US 1
QuantHies
Local
USI
Foreign 1         Total         I ust 1          USI           |
1 Mobilisation
LS
15.00
1500
1500
82,259
329.037
411 296
5.1 2        1 Land acquisition
ha
2,259.82
000
2 259 62
0
0
0
0
51-3         fsile clearance
1ha
1.594 67
6.779.45
8.474 33
0
0
0
0
Subtolel
62,259
329,037
411,296
SJ Accept Roads
5-2.1
Road Improvement
km
7909 37
31,637 48
39 546 85
0
o
0
0
5.2.2
Hew Road
km
17 400 61
89.602 46
87.003.07
0
0
0
0
523
Stream Oosting
No
22,596 20
90.392 BO
112.991 DO
0
0
0
0
Subtotal
o00
6.3            Diversion Intake
53 1
Eerlh ■Kcaveikm
cum
0.72
290
362
503
364
1 457
1.821
532
Rock excavation
cu m
1.B1
723
9 04
393
711
2642
3,553
533
Meet concrete
cu m
16 06
72,31
90 39
786
14.209
56,637
71,047
53 4
Structural concrete
cu m
25 99
103 K
129.94
450
11 695
46,776
56,473
535
| Formwork
»q m
10.17
40 66
50 85
1,463
15 082
60 326
75,41!
53 8
Sleet retniorcamenl
T
246 58
994 32
1 242.90
59
14 666
58 685
73.331
5 37
Unmeasured Seme
«
5 00
500
5 00
28W
11.345
14,182 |
Subtotal
59.563                238.253               297.617BARO-AKOBO PRO JECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consuftanls, Inc.
01-Dec-86
Max. Res. Level: EL 1.610
Dam Type: RockfMI
Inst. Capacity; 12.2 MW, 16.4MW A 21MW
Unit Prices
Cost Level:          Jan-36
Amount
Item
No.
DESCRIPTION
Units
Local
US 6
Foreign
USS
Total
USS
Quanlilles
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
6.4            Diversion Canal
5.4.1
Common excavation
cum
072
2.90
362
13800
9.991
39,965
49 956
542
Rock excavation
cu.m
1.81
7.23
9.04
128800
232.870
931,482
1,164,352
5.4.3
Earth fiN from borrow
cum
1.36
542
6.76
0
0
0
0
5.4.4
Hauling fill material
cu.m/km
010
041
051
0
0
0
0
545
Earth fin
cum
0.45
1.81
226
0
0
0
0
546
Lining concrete
cum
24 86
99.43
124 29
4.347
108,058
432,231
540.289
5.4.7
Structural concrete
cu.m
25 99
103 95
129 .94
0
0
0
0
5.4 0
Formwork
sq m
1017
40 68
50 85
0
0
0
0
5 49
Steel reinforcement
T
248 56
994 32
1,242 90
146
36.293
145.171
181,463
5.4.10
Unmeasured Hems
%
500
500
500
19 361
77.442
96,803
Subtotal
406,573GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
1.110
tnet. C
Unll Price*
*
Amount
\
/
/iVa /WSCRJPTTCW
I
J Untti
Local
USI
Foreign
USI
Total 1
US 4
local                Tweign 1                 Total         \
^uanUtin               US t                     US 1 \
US 1          |
A: CIVIL WORKS
6.0 POWER PLANT No J
f.f              PreflmirMri*«
[6 1.1 IjWoMItzaFlon
LS
is.cn
1500 I
1500
107,611 |             430.443 1                        53fi054 |
6 1,2 Iltndacqulsibon
ha
2.25982
0.00
2259 82
0
0
0
0
|6.1 3       |Stte clearance
ha
1 694 87
6,779 46
8.47433
0
ol
0
1
ol
Subtotal
107,811
430,443
538.054
8.2            Acctis ftoadt
6 2.1
Rend Improvement
tan
7.909 37
31,537.45
39 548 65
1?
134 ass
537,837
672 296
522
New Road
tan
17,40061
89 602 46
87 003 07
10
174,006
696,025
870,031
623
Stream Croealrtf
No.
Z2,S9B.2Q
90.392 00
112.991.00
01
0
0
0
Subtotal
308.465             1,233,662             1,542.327
6.3
Power Intake
63 1
Earth excevittan
cu.m
□ 72
290
3 62
110
ao
319
396
9 32
Rock excavation
cu.m
1 61
7 23
9,04
0
0
0
0
633
,
6.3.4
Lining concrete
cu m
40 66
162.70
203 38
0
o1
0
01
Sliuclural concrete
cum
25 99
103 95
129 94
450
11.695
46.776
58,473
635
Formwork
eq.m
10.17
4OM
50 05
1 350
13.730
54,910
68.648
6 38
Steel (Enforcement
T
246 56
99432
1.242 90
59
14 666
58,685
73331
6 37
Unmeaeured (terms
%
SOO
5.00
5.00
2.0O8
8 034
10 042
Subtotal                                                                                                                                                      42178
168.714
210,692
8.4
PenMock (luriace)
641
Common rxctMirtlofl
cu.m
0 72
290
3 62
2 400
1.738
6,950
5 666
642
Rock excavation
cum
1 61
7 23
904
250
482
1 808
2,260
643
Anchor bolt*
m
1356
54 23
67 79
0
0
0
0
6 4.4
Mail concrete
cu.m
10 06
7231
90.39
500
9 039
36 156
45,196 1
64 5
Structural concrete
CU m
2520
103 95
12994
0
0
0
0
'6 46
Formwork
eq m
1017
40 66
50 65
2,000
20 340
81 360
101,700
6 47
Steel reinforcement
T
248 56
994 32
1 242 90
50
12,429
49 716
62,145
648
Unmeasured rtema
%
10 00
1000
10 00
4 400
17 599
21 999
Subtotal
45,397
193 589
241,987BARO-AKOBO PROJECT Integrated Master Plan
TAMS Consultants, Inc.
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Max. Ret. Level: El. 1,110
Dim Type: Rockfill
Inst. Capacity: 112MW, 1B.4MW A 21MW Cost Level:                                                        Jin-M
Unit Prices
Amount
Item
No.
DESCRIPTION
Units
Local
US)
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign
USS
Total
USS
6.6
A: CIVIL WORKS
Powerhouse (surface)
651
Common excavation
cum
0.72
290
362
5.760
4,170
16.681
20,851
652
Rock excavation
cum
1.81
7.23
904
3 850
6 961
27.843
34,804
653
Earth M
cum
045
181
2.26
3,240
1.464
5,858
7,322
6.5.4
Mass concrete
cu.m
1606
72.31
90 39
836
15.113
60,453
75,566
6.5.5
Structural concrete
cu.m
25 99
103 95
12994
785
20.401
81,602
102003
656
Formwork
sqm
1017
40 68
50 85
2 406
24.469
97,876
122,345
65.7
Steel reinforcement
T
248.58
994 32
1,24290
160
39,773
159,091
198.864
65.8
Roofing
sqm
180 79
723 14
90393
136
24,587
96.348
122,934
6.50
Blockwork
sq.m
904
36.16
45 20
300
2,712
10 848
13,560
6.510
Miscetteneoua Metalwork
T
723.14
2.892.57
3,61571
25
18079
72.314
90.393
6.5.11
Slope Protection
sq m
452
1808
22 60
0
0
0
0
6512
Unmeasured items
%
1000
1000
1000
15,773
63.091
78.064
Subtotal
173.501               694,006               867,507
fit
leu m                                   072
2.90
3 62
0
0
lcu.m
1 81
7.23
904
0
oT
I* ~
500
5 00
500
0I
o
nO0
------ 04-1----- 4
------------------- 4    ------
4
1
SubtotalCCJJVrEFTO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Mu. R«f. LreWr EL 1.110
11
Dam Type:           RockflH
IniL Capacity: tUMW 1I 4MW* 21MW
Cocl Levek             4an-M
r   ~r
Unit Prices
Amount
1
liter
/Ato.
1/
I Local                 Foreign
/desc/wpdojv
| Unit!
I Us|
USI
Total
us*
Local I           Foreign 1
Total        I
Quantities
US |
U5$                     US|         I
7.0
7.1
A; CIVIL WORKS
DIVERSION WATERWAYS No.3
PreHrrtniriM
I7A.1      [MobtaaUon
LS
1500
1500
1500
222 634
890 536 '
1 113 170
712       I lend acquisition
ha
2,259 82
ooo
2.259.62
0
0
01
0
17.1.3     |SAe clearance
ha
1,694 07 j
6,779 48 j
fl 47433
0
0
0
0
Subfetat
222634
890.536              1.113.170
7,2 Acceci Road*
7.2.1
Road improvement
tom
7.QO9.37
31,637 46
39,546 BS
0
0
0
0
7.2 2
New Road
km
17.40061
69,802 46
87D0307
0
0
0
0
723
Sdeam Crossing
No,
22 598 20
90 392 BO
112 991.00
0
0
0
0
ftutHntnl                                                                                                                                                              0                           0                           0
7 3             Diver «tan Intske
, 731
.
7.3.2
Earth excivatlon
cu m
072
2.90
3.62
923 1
668
2073
3 341 1
Reek accavelion
cu.m
1 01
723
9 04
013
1 470
5,M0
7.350
733
..
734
Mass concrete
cu.m
1808
72 31
90 39
1 828
29^95
117.579
146,974 I
Structural concrete
qu m
25 99
103 95
129 94
450
11 695
46,778
58 473
735
,,
7 36
Formwork
aq.m
10.17
40 68
so as
1.846
10774
75,095
93.869
Sleek lalnloTcement
T
248 5fl
994 32
1.24290
59
14,086
58.665
73,331
737
Unmeaaured Items
U
SOO
5.00
500
3833                  15.334
19,167
Subtotal
80,501
322,004
402505BARO-AKOBO PROJECT Integrated Matter Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
TAMS Consultants, Inc.
01-Dec*M
COST ESTIMATE
Max. Res. Level: El. 1,811                      Dam Type: Rockfill
Inst Capacity: ttJMW. 1S.4MW & 21 MW Cost Level:                                                      Jan-M
Unit Prices
Amount
Mem
No.
DESCRIPTION
Unit*
Local
USS
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
7.4        Diversion Canal
7.41
Common excavation
cum
072
290
3.62
42.000
30.408
121632
152,040
7.4.2
Rock excavation
cum
1 81
723
904
387,000
699 696
2.798.784
3.498,480
7.4.3
Earth fin from borrow
cu.m
136
542
678
0
0
0
0
7.4.4
Hauling fill material
cu.m/km
010
041
051
0
0
0
0
7.45
Earth fMI
cu.m
0.45
1.81
226
0
0
0
0
7 46
Lining concrete
cu.m
2486
99 43
124 29
11,810
268.601
1.154 406
1.443,007
7.4.7
Structural concrete
cu.m
25 99
103 95
129 94
0
0
0
0
7.48
Formwork
sq m
1017
40.68
50 85
0
0
0
0
7.49
Sleet reinforcement
T
248 58
994 32
1.242.90
427
106,144
424.575
530,716
Unmeasured items
%
500
500
5.00
56.242
224.970
261.212
7.410
Subtotal
I
, •gumerq hydroelectric. project
PREFEASIQILITY STUDY
COST ESTIMATE
Unit Prkea
Unit*
Local
US I
Foreign
US*
Total
US*
Qu Antilles
lfl«l I
I UM i
B: ELECTRO-MECHANICAL EQUIPMENT
1.0           DAMS AND APPURTENANT WORKS
lt.1
|power supply to rha dam
LS.
10000 00
40.000.00
50,000 00
1
10000
40000 1
50,000 1
LI    (High Pressor* SJfcfe Gelet - Low Level Outlet
Intake and BuStie&d Gates ’ Low Level Oultat
each
800.00
3200 00
400000
4
3,200
12.800
16,000
each
0 80000
39,200 00
49,00000
4
39 200
156.800
VJ6.D0Q
Subtotal
I1.4H                 209,m                 191,900
2 0 POWER PLANT No.1
Power Intake Gates
,
21
each
900 00
3,200.00
4000 00
2
1,600
6.400
9 000
22
Penstock
T
494 00
1,976 00
2,470.00
313
154.822
616488
773,110
23
Inlet VifoM
each
22,000 00
Bft,ODO 00
110 000 00
2
44,000
176,000
220,000
2.4
Turbines, Govemcfs and TurWne Auxiliary Equipment
each
116000 00
464,000 00
580 000 00
2
232,000
929,000
1,160 000
2.5
Generators and Gan er al or Auxiliary Equipment
each
1841, MOOD
672,000 00
640 000 00
2
336000
1,344,000
1,680 000
2.8
PcwerhcuM Grant
US.
45,000 00
180 000 00
225000 00
1
45 000 .
130000
225.000
27
Station AuuHiary Mechanical Equipment
IS
90.000 00
276.000 00
345,000.00
1
69 000
278 000
345 000
29
Station AuaWary Electrical Equipment
LS.
181,000.00
724 000.00
905,000 00
1
181,000
724 000
905,000
20
Main TFan*toim*r*
•a ch
36.000.00
152 000 00 ;
190,000 00
2
76 000
304.000 |
380.000 !
2 10
Switchyard Equipment
LS.
110,000 00
440 000 00
550 000 00
1
110 DOO
440 000
550.000
2.11
Unmeasured tttms
10
10
10
134,922
499 689
624 611
Subtotal
1,174.1*4            S.4H.477             1,970,711
3.0
.1
DIVERSION WATERWAYS No.1 DMtston Inttka Gate*
each
I
2 I 1,0x7
6.400
3.000 |BARO-AKOBO PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS ConauMante. Inc.
01-Dec-H
Max. Res. Level: El. 1,810
0am Type Rockffll
litem
|no.
_______________Inst. Capacity: 12.2MW, 18.4M1
Unit Prices
M4 21MW
Local
DESCRIPTION
Foreign                   Total
Unit a
USS                      USS                       USS
Coat Level:       Jan46
Amount
I Local             Foreign               Total USS                 US $                  US I
4.0
B: ELECTRO-MECHANICAL EQUIPMENT
POWER PLANT No.2
41
Power Intake Gates
each
600.00
3 200 00
4,000 00
2
1 600
6.400
8000
42
Penstock
T
494 00
1 97600
2.470 00
341
168,454
673.816
842 270
4.3
Inlet Valves
each
26,000.00
104.000 00
130.000 00
2
52.000
208.000
260 000
4.4
Turbines. Governors and Turbine Auxiliary Equipment
each
147.000 00
568,000 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
506 000
2 032.000
2.540.000
4.6
Powerhouse Crane
L.S.
45.000 00
180 000 00
225 000 00
1
45 000
180.000
225.000
4.7
Station Auxiliary Mechanical Equipment
LS
73.000 00
292.000 00
365.000 00
1
73.000
292.000
365.000
48
.
49
Station Auxiliary Electrical Equipment
LS.
261 000 00
1.044.000 00
1.305 000 00
1
261,000
1.044.000
1 305 000
Main Trenalormer a
each
56 000 00
224.000 00
280 000 00
2
448.000             560,000 120.000             480 000            600.000
112.000
4 10
Switchyard Equipment
L.S.
120 000 00
460.000 00
1
4.11
Unmeasured Item*
%
10
10
10
817,527 8.992.787
Subtotal
163 505 1 791881
654 022 7.194.238
DIVERSION WATERWAYS No.2
Diver Bion Intake Gates
800 00
3.200 00
4000 00
SubtotalAto.    /DESCRIPTION
jltem
| Untie
I Local
I VS I
Unit Prices
Foreign
US t
Dem Type; Rocklin
12.2MW. 18.4MW & 21 MVtf
Total
USI              Qiuntnlee
Loot I
USt |
Foreign 1
US i           \
Total        \
US 1 J
B: ELECTRO-MECHANICAL EQUIPMENT
6.0             POWER PLANT No. 3
far
—
IpOTW IntiteGatOT
Jeach
800 00
320000
4,000 00
2
1.600
8 400
a.aool
M
1 Penstock
T
494 00
1.975 00
2,470.00
352
173 088
695.552
869 440
'6 3
W Vitwa
each
26 00000
112,000 00
140.000 00
2
56,000
224000
200,000
64
Turbines, Governors and Turbina Auxiliary Equipment
each
187,00000
666.00000
835 000 00
2
334,000
1.336.000
1,670.000
6.5
Generator* and Generator Auxlfmry Equipment
each
276.00000
1,104 000.00
1380 000,00
2
552 000
2 206,000
2,760 000
86
Power Ixxjm Crane
L.S
45.000 00
160 000 00
225 000 00
1
45*000
180,000
225.000
67
Staton Auxiliary Mechanical Equipment
L.S
75 000 00
300.000 00
375,000 00
1
75.000
300,000
375 000
68
Slaton AunAary Etaclrical Equipment
LS.
300.00000
1,200.000.00
1 500,000 00
1
300 000
1,200 000
1.500 000
6.9
Main Trenafonnert
each
64,000.00
256,000 00
320.000 00
2
128.000
512000
640.000
6,10
SwrtchyatcJ Equipment
L.S.
125,000 00
500 000 00
825 000 00
1
125.000
500,000
625.000
8.11
UnmeBiUfwd llama
%
10
10
10
179.049
716.195
Subtotal
095 244 1
1.M1.I37              7,878,147             9.847,884
7.0
]7 1
L-J--------------
DIVERSION WATERWAYS No. 3
Subtotal
WW.UU I 3.200.00 | 4 000 00 I
21 060 00 [          84 240 00 |            105 300 00
2J 1,600 |
1,800
6,400 |
8,400
a.ooo 1
8.000
B.O
81
TRANSMISSION LINES
Transmtaalon Line 132AV from Gumero No 1 Io Gambeta-Go<e
km
14 j       294 840
1.179 360 1          1 474 200 |
63
j ranamiawon Line t jj-kv ir<xn Latjmeio nw,2! w> Gurnaio No i TrarwWt atari Line 132-lcV from Gumaro No 3 Io Gumero No.2
km
km________
21,060 00 |
21060 00,
B4 24Q00 1
84 240 00 1
105,300 00
105 300 QQ
9          18B 540 ioT         400,140 "
884,820
,
758,160 J
1,600 560 |
947 700 I
2,000 700|
3.438.080              4,422,800tDRAWINGS
FOR
GUMERO HYDROELECTRIC PROJECTDrawing
LIST OF DRAWINGS
Title
GU-1                  Project Plan
GU-2                 Project Profile
GU-3                 Reservoir Plan
GU-4                 Gumero Dam - Plan
GU-5                 Gumero Dam - Profiles
GU-6                 Gumero Dam - Cross-Section and Pov,tt Outlet GU-7                 Gumero Dam - Spillway Profile and Sections GU-8                 Power Diversions - Plans
GU-9                 Power Diversions - Intakes
GU-10 Power Diversions - Canal Section and Penstocks
GU-11
Powerhouse No 1 - Plan and Section-
ztt-js
I
—
Baro-Akobo Basin
Addis Ababa
Bedelc
Jrmmn
PROJECT LOCATION
PROJECT LOCATION MAP
4QCV-
—J
ministry of water resources
■ v --
ADOtS A0A0A ETHIOPIA
-- —
~                TAMS - ULG
MEW YORK - LG NOON - ADDIS ABABA
BARO-AKOBO MASTER PLAN PREFEAS1BIUTY STUDIES
OJMERO KTDROELECTWC PO*ER PROJECT PROJECT PLANGumero Reservoir
Normal Min. Level El. 1600 Norrnol Mox. Level El. 1610
• 5615
Headworks of Diversion 1
'Q. 1465
and 0-13n-/»
Penstock 2 Ce
Diversion 1 Rowemouse
/ El. 1340
Headwo^s  of  Diversion  2
El. 1305
Power Con el
Penitqc- 2 0®
Divertor 3 Powerrc-ute
£J. SCO
£ !N kilometers
ZZ
ministry of water resources
AX'S AfiAfiA ETHIOPIA
TAMS - ULG
K£W YORK - LONDON - A DOTS AS ASA
BARO-AKQ60 MASTER PLAN PREFEASIB1UTY STUDIES
OJUERO hydroelectric power project PROJECT PROFILE
Date: Qctaber 1S96Minimum Water betel EL 1600
1               =r_
LEXAS
i. ?t>7~ p. VJUEO
BARO-AKOeO MASTER PLAN PREFEASIBILITY STUDIESI
MINISTRY OF WATER RESOURCES
ADO IS AB KB A (THIOP IA
TAMS - ULG
____________________M(V YORK - IQMDCM - ADO IS ABABA_________________________
|BARO-AKOBO MASTER PLAN PREFEASIBILITY STUDIES GUMERO HYDROELECTRIC POWER PROJECT
GUMERO OAK - PLAN
x October 1W
I                  Me 6U -4Crest El. 1615.0
Existing Ground Surface
Gumero River
__        i
'-J111
^7.
4 Diversion Tunnel
PBQFILE QN TOE! INE-PF PAJL,..,
J Intake Tower
^Access, Bridge
Access Road
Existing Ground Surface
- {.v'ulV"* ^ *;*’<-*
3.5 < Diversion and Outlet Tunnel
Slope IS %
PROFILE ON DIVERSION AND OUTLET TUNNEL
(. Spillway Crest EL 1610.0
Existing Ground Surface
MINISTRY OF WATER RESOURCES
____________ ___________ ADO
IS
ABABA
ETHIOPIA
TAMS - ULG
_______________ new roes - lohoon . ADO IS ababa__________________ BARO-AKOBO RASTER PLAN PREFEASIBILITY STUDIES
GUMERO HYDROELECTRIC POWER PROJECT GUMERO DAM - PROFILES
CXtob^r tW
I Dwg He GU - 5I Dam
GUMERO - ROCK FILL DAM - TYPICAL SECTION
ELEVATION A - A
MINISTRY of water resources
*DDIS ABABA ETHIOPIA
TAMS - ULG
YORK - LOWOOW - AOOIS KBABA
BARO-AKOBO MASTER PLAN PREFEASIBILITY STUDIES
GUMERO HYDROELECTRIC POWER PROJECT
_______ DAM CROSS - SECTION AND POWER OUTLET
O»f : Octtf 1tM_____________________ | Owl He 6U - 6______________________Spillway Crest EL 1610.0
Grout and Drainage Gallery
_____ •
El. 1606.0
*.— xl
*
in
Grout Curtain
0.07S Drain Holes ^5.0
075 Drain holes a ^0-0 Itffi--------------
SECTION tmooUGH SPILLWAY CREST STRUCTURE
SECTION A - A
STILLING BASIN SECTION
MINISTRY OF WATER RESOURCES
ADDIS A>A1A ETHIOPIA
TAMS - ULG
NEW YORK • LONDON - ADDIS ABABA
HOTE Drains and Anchors Same as on Chute
BARO-AKOBOmaster plan PREFEASIBILITY STUDIES GUMERO HYDROELECTRIC POWER PROJECT
SPILLWAY PROFILE AND SECTIONS
SECTION B-BA
Power house
El. 800
Power Canal
Diversion Dam and Intake
El. 1305
( Diversion 2 I
newer house El. 13^0
5:
3 5M wo sk yoc
Scale 1        50.COO
MINISTRY OF WATER RESOURCES
ADDIS ABABA ETHIOPIA
TAMS - ULG
XW YORK - LONDON - ADDIS ABABA
barq.akoro MASTER PLAN PREFEASIBILITY STliniFR CUMERO HYDROELECTRIC POWER PROJECT
POWER DIVERSIONS - PLANS
Sriie 1 • 50,000
:        October
[ Dwg No GU - 8Intake Gates
Existing Ground
Intake
Structure
DI versJon Sluicew ay
elevation
UPSTREAM EIEVATION OF SPILLWAY. AND INTAKE.structure.
Scale 1:1000
Concrete Ogee Spillway
and Roller Bucket
Emergency Spillway
SclUvay
□ Iverslon Sluice and Outlet for Flushing Rocks_ _—
_Ex_i»tlng_ Ground Assumed Rock Surface
Gate Operate
Platform^—
Gated Intake structure
Rock Trap
REFLECTED SECTION
Scale 1:200
MINISTRY OF WATER RESOURCES
___________ ADO IS ABABA ETHIOPIA________________
PLAN
TAMS - ULG
<V YOftX - LOMOOH - A DO IS ABABA
baro-akobo master plan PREFEASIBILITY studies gumero hydroelectric power project
POWER DIVERSIONS - INTAKES
' Dwg MO G'J - 9Headrace_Canal_
Existing Grocrd
Surface^—
t penstock
Existing Ground Surface
Assumed Rock
Surface---------
rMRO 3 PENSTOCK AND POWERHOUSE PROFILE
15 Canal Lining ]typ)
Cyal Invert
POWER CANAL
TYPI CAL SECT I ON ON STEEPCTTLOPING GROUND
Existing GrtxMxl
_S ur face-------
&0 2 PENSTOCK AND POWERHOUSE PROFILE.
Headrace Canal^
I----- -H
POWER CANAL
TYPICAL SECTION ON GENTLY SLOPING GROUNEL
^^fSTOCK AND POWERHOUSE PROFILE
MINISTRY OF WATER RESOURCES
ADDIS ABABA ETHIOPIA
"
TAMS - Utfi
MEV YORK - LOWDOW - ADO IS ABABA________________________
BARO-AKOBO MASTER PLAN PREFEASIBILITY STUDIES
GUMERO HYDROELECTRIC POWER PROJECT
POWER DIVERSIONS - CANAL SECTION AND PENSTOCKS
:       OcUMf
| Ov> He GU ~ 10TYPICAL LAYOUT
NOTE:
Each of the three Power
Plants contain two units:
Powerhouse No. 1:
2x6.1 MW
Powerhouse No. 2:
2x9 2MW
Powerhouse No. 3.
2x10 5MW
ministry of water resources
ADCNS ABABA ETVOOPIA
TAMS - ULG
HEW YORK - LONDON - ADOS ABABA
BARO-Ai^BO MASTER PLAN PREFEASIBIUTY STUDIES
ajuero hydroelectric power project TflSoSL POWERHOUSE - PLAN ANO SECTION
Date:
October 1^96
Dwg No GU - 11APPENDIX 4 1
ITANG DAM
Detailed Cost EstimatesBARO-AK060 PROJECT Integrated Master Plan
ITANG IRRIGATION PROJECT PREFEASIBILITY STUDY
DAM COST ESTIMATE
Max. Res. Level: EL 431.1 Dam Type: CAHhfin
Item
NO
DESCRIPTION
Local
Arnounr Foreign
i___ ^4
A: CIVIL WORKS
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
DAMS AND APPURTENANT WORKS
Preliminaries
Access Roads
Diversion Canal
Cofferdam
Embankment Dam
Spillway
Irrigation Intake
1.703.059
7.909
250.866
72.680
8.003,262
1.126.418
189.534
6.812.237 31.837
1.003,464 290,720
32.013.047 4.505.673
758.138
8.5
1.2!
X
4001 851
K
TOTAL 1.0
I 11.353,729
45,414,916
KJtl
1.0
1.1
1.2
B: ELECTRO-MECHANICAL EQUIPMENT
DAMS AND APPURTENANT WORKS
Spillway Gates
Irrigation Intake Gates
406.000
24.000
1,624.000 96.000
2.03T
TOTAL 1.0
430,000
1,720,000
2.15C0
TOTAL BASIC COST
Physical Contingencies                20% Engineering and Administration                   10%
TOTAL CONSTRUCTION COST
11,783,729 2,356,745 1,414.047
15.554.522
47.134.916
9,426,963 5,656,190
62,218,089
58W*
11M5
71.7^F*F<ouEC"r
PREFEASIBILITY STUDY DAM COST ESTIMATE
Dem Type
Cort Lrwat
litem
L DESCRIPTION
|              Unila |
Local
uss
US $
T04al        l
US I I Duintnlea |
Local
USS
Furatyn T
US 1
ToUI j
USS 1
A: CIVIL WORKS
1.0 DAMS AND APPURTENANT WORKS
1.1             Pr«Umln«rlM
111 1
Vtairtlzaitoci
%
1500
15.M
1500
1,703.059
8612237
8 515 297
1.1.2
Lind Bcqultlta
ha
2259 02
0.00
2 259 82
0
0
0
o
113
Site cbartnca
ha
1 06487
6 779 40
8 474.33
0
0
0
0
Sudlolrt
1,703.050             6812 237            8.515,297
12             Access Ro*dt
Il21
Read Improvement
km
7,909 37
31,63748
39 54805
1
7909
31,637
39 547
1 22
Naw Road
km
17,40061
69,602 48
67,003 07
0
0
0
0
|l 23
Stream Croa&lna
No.
22.598 20
90 392 80
112,991 00
0
0
0
0
Subtotal
7,909
31.637
39.547
1-3
Diver ikon Canal
13 1
r iwrvnon csxjvrtxxi
cu.m
0 72
290
3.62
330 000
238920
955 680
1.194.600
1 32
Rock Encavrtion- -
cu m
101
723
9 04
0
0
0
0
11 1 Ti
EirtTi Fifl
cu m
0 45
1 81
226
0
0
0
0
1 34
Inina Conceit
cu m
2825
11299
14124
0
0
0
0
1 1 Si
cu m
25 99
103 95
129 94
0
0
0
b
136
iqm
10.17
40 88
50 65
0
0
0
0
T
248 58
904 32
1 242 90
0
0
0
13 7
13 8
0
Linm«*Lir*d ee4Ti»                    --------- ------------------
%
500
500
ADO
11 946
47,784
50 730
---------- ----- ‘
SuMtXal
250,868            1003,464             1,254,330BARO AKOBO PROJECT
Integrated Master Plan
ITANG IRRIGATION PROJECT
PREFEASIBILITY STUDY
DAM COST ESTIMATE
TAMS Consultants. Inc.
07-Nov-H
Max. R<Ba. Level: El. 431.8
Dam Typa: Earthfill
Coat Level:           Jan-88
Unit Prices
Amount
Item
No.
DESCRIPTION
Unite
Local
USS
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
14             Cofferdam
1.4.1
Foundation excavation * Common
cu m
0.72
290
362
10.000
7.240
28 960
36 200
1.4.2
Foundation excavation - Rock
cum
181
723
904
0
0
0
0
143
Borrow excavation - Earth
cum
068
2.71
339
48 700
33 019
132,074
165.093
1.4 4
Borrow excavation - Rock
cu.m
098
384
480
3000
2 880
11 520
14.400
1.4.5
Hauling fin material (over 2 km)
cu.m/km
0.10
041
051
0
0
0
0
146
Unprocessed fti (placement]
cu m
045
1 81
226
48 700
22 012
83 050
110062
147
Ptocessed M (placement)
cu m
1 36
5 42
878
3.000
4068
16 272
20.340
1 4.8
Unmeasured items
%
500
500
500
3 461
13844
17 305
Subtotal
72,680
290.720
363400
1.5            Embankment Dam
1.51
Foundation excavation * Common
cu.m
072
290
382
437.000
316388
1 265 552
1 581.940
152
Foundation excavation - Rock
cum
1.81
7.23
904
0
0
0
0
1.5 3
Borrow excavation - Earth
cu m
068
2.71
339
1,316.000
892.248
3,568 992
4.461 240
15 4
Borrow excavation * Rock
cu.m
096
384
480
159 000
152 640
610.560
763 200
Il 55
Hauling M matertai (over 2 km)
cu mAm
010
0.41
0 51
0
0
0
0
1156
Impervious core
cu m
228
904
11.30
1,581 500
3 574 190
14.296,760
17 870 950
11 5 7      |Unpcocesied Wt (placemen!)
cu.m
045
1 81
226
1.316.000
594.632
2 379 328
2 974 160
(15 6        J P i oceaxed fl (placemen!)
cu m
1 36
5 42
678
0
0
0
0
\159 iFMm
|cu m
3 30
1356
18 95
86 000
223 740
894 BOO
1,118,700 1
\I5 1O \D«aWm VanUbona
leum
330
1360
1695
481 OOO
1 830 590
6 522.360
6.752 950 J
\l6.1 \      \Rip (»p ( pUcemenl)
leu m
Im
1.13
4 52
5 65
210.200
237 526
950 104
1 187 630 /
\5 5
1*2 \o«Wmxx lor QfoUUrxi             Orated
11 30
40 20
M SO
0
O
\\ t» 5^
I1
112 90
4fi1 Q7
MM 90
0
O
°r            ° /
0 oo
B OO
K on
int ton
1     O /Qj
574 <31 /                     » 4M** * »V /PREFEASfBILITY STUDY
DAM GOST ESTIMATE
Jan-M
UnH P^Ctt
local
Foreign
Total
^OCtCftlPTlOW
A: CIVIL WORKS
US 1
USI
USI
G0« L*v*L
Amourrt
Fwrlyn
U5|
1.8           SpHhvff
161
Bulk txca«inxt. Common
cu.m
0 72 i
290
362
16,000
13032
52,128
65 150
1.62
Bulk txcMUon - Hock
cu.m
1 81
723
904
16,000
32 544 1
130176
152 720
16 3
Structural eicarttmn - Rock
cum
462
18 08
22 50
0
0
0
0
1 64
Maaa conaetfl
cu m
1806
72 31
90 39
37,213
672 737
2,690 940
3.363.683
165
Struclur concrete
cum
7599
10395
129 94
5 850
152.030
608,119
760 149
1 66
Formwork
*q m
10.17
4008
50 85
S.490
55,033
223 333
279 167
1 fl 7
Sleet re*f JocciBmml
T
246 50
994.32
1.242 90
488
116 335
405 342
581 677
IBS
DnAng <<x dialns
m
11 30
4S20 '
S6 5O
210
2373
9 492
11 865
16.9
□rifling for pouting and                    flan)
m
15 52
03 27
79 09
250
J 954
15.616
19 773
IS 10
AncNxa (tnd. drilhng and grouting}
T
2 952 9fl
11 931 85
14914 61
67
19,980
79 943
99 929
1 6.11
Grouting
T
11290 '
451 97
564 94
35
3955
15619
10 774
16 12
Uivnaaaufed llama
%
500
500
500
63 639
214,556
268,195
Subtotal
__ ____________
1J28.4IB            4,505,673            5,032,091
1 7           kflgatlDO Intake
Common Excavation
. 17I
cm m
0 72
2 90
362
I.OB
724
2 696
3,620
1 72
Rock Excavation
cu m
1 81
7 23
9 04
0
0
0
0
1 7.3
Earth Fill
cu.m
0 45 anAA
1 fl!
226
0
n
0
0
0
1.7.4
1 75
UnInfl concrete                             __ Structural concrete
cu.m
cum
2599
103 95
129 94
2.025
52 626
0 210 503
0 263 129
176
Formwork
iq.m
10.17
4068
50 65
5075
61 783
247,131
306 914
177
Site! ralnforcemant
T
240 58
994 32
1,242 90
263
66.377
2B1 506
328.863
1 79
Unnwauied Hama                              —
'i
500
500
500
9,025
36,102
45 127
Subtotal
189.534               758 130                947,672*APPENDIX 4-2
ITANG IRRIGATION PROJECT
Economic AnalysisATable I: Economic Return by Crops
Cofflljrt
Output KgJhi
Eco«ch»iic price ■ BJrmcwi
' Grow revenue per hectare |Blrv|
*eif i
95Q
4.512
4 2M
W2
■ 0G0
4.512
4 5*2
* 5OC
4513
«7M
<wr4
2,®C
<412
9 024
'e#5
15®
*512
*1.2*3
1 Input Coats ■ Bwrmj
4r$
',1»1
K15
Net rmnwe per haem iBern
4.415
2.113
4  lift
4  no
IT
4,114
i rro
¥ear f
W2
’’f# J
Output KflflM
re#'
3,210
3 140
4 fr?G
5.DOO
Economic price ■ Birrrtcn
y a-5
5 300
i jn
1 JT3
1 373
1 373
Croea revenue per heder* fWm
1 373
3 3J*
4311
55M
fr ws
5 365
Input Coeto - Binflu
•M
MO
1.025
l.frll
Mt revenue per Mem fBIrr)
1.013
1.JW                             <S4J          SJ12              M»
*e#f CMpvl Kgrtll                                                    1 300
Ecwwmbc pHc» - BlITftDH
Grow mnw per hectare (Birrj
1 XX
’ 'TS
Input Com Or-lu                                                 601
Het nvwui per Wcfrw iBirn
f, 1 a
»r#2             *e#J           re# 4          Y«r$ 7700            3?«           4000           40® j i no           1.330          1.330          1 nc ?ta           4.921          5120          5 5?0
860          1.025          1 0U          1,011 10<l             UM           4.MJ          4J07
Sff/a 0mri
Output Kg0u
Econo me pre* - B«mcwi
’■e# i           'e#2           *e#J           Y*#4         Ye# 5- 2.135         I.97C          4 »35          SOW           4C®
TB1
’M            7Bfl              •M
Oom rrvemrt per Mem rBirri
1.659
JW
3 IM
4.729
4 -JI
input Coad . BlfT/ha
794
105
• 14
•SC
•«
Hat mua p* hecm iB*n
r
t<s
1.134
1074
1*71
3.MI
tfegwnAta
F# *
6.300
HO
9 103
1225
1*77
Ye# r
1 500
rear 3
1WC
•10
5.M
f—r J
5 WO
■ IB
55®
3,225
1K3
re# J
35®
2.490
B 715
**# 4
72®
•to
5832
Year 5
7.200
■10
5C2
1226
2.120
re# 2
25®
3226 3225
UM
2.4W          2.49ft
¥«#4
4  5®
2.490
Years
4 J®
2 4®
3 733
• 225
• 1.205       11 205
1 354 ' 055 1 054 1 CH 1 0*7
24*1 1170 7.151 15.1** 101*4
Wwatfi^rwwwts
2.500
1 11*
2 W9
225
ZfiM
*■# 1
3 2®
1.115
3. S3?
335
1.411
3»®
1J1S
4 305
2rt
4,Ml
**3C
1.11*
5.0®
225
4,111
Super Gena
Output Kppia
Economic pnee ■
Crai mnue per haem |Mi<t|
input Cods • thrnTia
Net revenue Mca1* lB«?i _
re# J           W4
t aoo          9 5®          * 500
2 an           2 fill          5 8*1
’B >’fl7 35,470 J5 4T0
3 J«
I J.3W*
3*46
H321—
1 *46 3.445
J1034Table 2: Cropping Build-up (ha)
2009
1 100
1 100
2010            Mill        7012-         MU         MM         2015          2010             Ml/             Mil         MN MMl 2021
2022
1 100          1.100         1 100          1100 I        1 100         1,100          1 100         1 100         1 100          1 100                    1100 MOO        I MOO 1.100          1 100          1 100         1,100         1,100          1 100          1 100         1 100         1.100         1.100         1.100] 1.100 I 1.100
1 100          MOO          1.100 |        1 100         1 100 1       1 100          1 too         1,100         1 100         1 100          MOO         1 100         1,100          1 100
1.100
1 100
1 100
I
MOO 1 100 ' 1 100 1 100 1 1 100 1 100 1,100 1,100 1 100 1 100 MOO 1,100 1 100 1 100, 1 100 ' 1.100 1100 1 100 1,100 1 100 1 100 1,100 1 100 1 100 1.100 1 100 1 100' 1 100 1.100 1 '00 1 too 1 100 I 100 1.100 1 100 1 100 1 1 100 I 1 100 I MOO
1 100 1.100 1 100 1 100 1.100 1 100 1.100 1100 1100 MOO ! i ioo 1 100 1,100
,100
1 100         1 100         1 100         1 100         1 100          1100         1,100         1 100       . 1 100         1 100          1 too
1
1.100 1 100 1 100 1 100 1,100 1.100 1 100 1 100 1 100 1 too
1 too        1.1OO         1 100         1 100         1 100         1100         MOO         1 100          1 100
I 100         1 'CO         1 100         1.100         1,100          MOO         MOO          MOO 1.100          MOO           ,100          1,00          1 100          ,,00           MOO
1 100 1,100
1 100
1100          MOO         1,100         MOO
1 100
1 too
1 too
1 *00
1 100
I--------------
-
!*1
1,100 MOO MOO MOO , 1 too
1 100         1 100         1 100          1 ioo .       1 100
I
------ [
1
1.101
r ?«•
».m       11,«M        1J.1M        nioo        14. MO       10 4M        H.M0 '         tr.Mi       1F.H1        I7.M1        ir mir
■
[•
II H
1■
8
5
1
1Table 2: Cropping Build-up (ha)£
CQ4 »i
oort j    *
1
■I
1
■
we
a» r
ax i
cat r a» e
ax £
—           --------- - <HK E
«x c
Oto E OCX < OKI OWE ax e
1r
■
1
ri<K        zjor
do* r
OCXE
wi
mT
OOC I ]
»«<x
tit
DOC
ooc
'CMX
rn>
UC
ax
ooc
ooc
rp>
fJJC
ooc
in*            OO1>
me
MC'C
ooc
—
DM
L----------- —
oot
1-----------
■■
ooc           ooc          ooc           ooc          OOE
°*
ox □DC
ooc DOC
ooc
ooc OK
ooc           ooc       ooc           ooc          Ooi~’ DM          «              me           ox
ooc          OOC
DOC ooc ooc
OOC ?«— DOC
OOC «x ooc
oot
ooc          DM           Out          DOC
DK           OK           OOC        ooc          DK
□DC
ooc oot OK OOC
ooc ooc OOL ooc
OOC
DOC
DM
ooc
DOC
DOC
OOC one
ooc oot
K
ox
ooc
ax
ax
ax
□ex
ax
OOC
DOC
low |« OK OX loot OOC DM DK
l«K cot ' DK OOC
loot            ooc          ooc       P»c
wc           «       OQC
OK
ooc          OOC
OOC        DOC
ewe
ooc          ax
DK ooc
OK oat
ooc          DOC         DOC ax            ax            «*
OOC        □or
IWE
KOE      |moc
IkOC       HOC           »iOd
ax IX*
SlotTable 3*. Benefit Build-up (Birr ,000)I
■ff'rr
♦ft w
j——r»»
1 mtt            wet             Mier          inti
Ill'll
•«♦!
| FW 1            Bic’l        f **•
•l«<b         •J»*l i |        —
kt< ■         •it b               ■Il r         |
k/c
•KJ I jw i
•rt’k •rt I
—
i
, O*v 1
wrl                    MO             •Ft
1          rxn              tlQ
• M 1 1W k on 1
•rt'l • F« 1 ■M 1 •w 1 k» L
•rt 1 0-FL k ttC'l •K 1 •H 1
■rt ( •Wl Ml •Ml •M k
1 »«’•
UK
•IB
ocei
iwi
»K
kllB
orr k
art
kit
OCE 1
L« k
-1
’1
■
•Ml              IM L
■
J 0*6 1 ®rt k mi | ■rc k
D W 1           ■Ml           |  •rt 1            •M I
[IK •            •K 1            ■M 1           •klk
IM I             8KI             mi
OM 1           •K 1            m k             •W k
an
kit
<K£k »kl
rtl k
•tc
ki« BM
■
Ml
•M I
________
•rt k            •rt 1            •FG k
| ,t5 *
•M l            Ort I           Ort •
8K l             •KI              Ml
»rt 1
■M k
•K'k             trs i-           ■rtk             •M k            •Ml
IM I            OCZ 1        ♦kt
•rt 1 IMk DCE L ’*■ a>t
•Mi              •M 1
•rt 1            ♦M k          •Ml
IH k         OCE k     HO
•Ml             BIS I           ■Ml
■Ml             Ml               ■ M k
•rt 1
DM k          ■n«            Ml
<MC I
1- 1
f
ft IM l          IIM 1              Ml
■rt k
Ml
•ft I
Ml
■K I
•rt t             IM L
•rt k
Ort I
•M 1
•KI
MS 1 art 1 Ort 1 •K'L kft b
—r-
•tg 1 Ort I •rt k m 1 •»« k
Ktl
. IW 1
II RMr 1
| BK’I
EW k 1 •is 1 8M 1
•rt 1             ■M'l           Wk
•rt 1            BM k
aural »4<>5
mi               m k            «rt I            BK k          OK k          •rt k            Brtl           •K k           ■rt k
[?utt
uo;
UK              ■ide
ZIDZ           OIOZ          Cltf             MM             rioc            zioe            MM         tOl0f       WK            IMKV
| MI O*
li twz
VM*4C •rt« ICkM
4E» ’ J»E k COZ
MO’«           lei'it            (Wit            ♦UK            WVt           ••♦it            IK'Oi          ’ (Mil           Mb M      | Kl'kk        I"1'*
--------
1---
1 •*’c         M» C            09U            «k k            MG-
'1 06* e              wr £              Wl            0«E             Oflk 1         MV
____
II **’’*
86T I            nor;            ME E        I e«k l             »GU
1_______  1
1- —
SRt t           WU              86k I
,*«
•Ml           1 WEE          OB'. 1
.........
1__
1 -1 !
--t
I w t            ’ 05k €         | 86* E        I m» z          I Nl't 06k I
I M* I
QGV t
•nr c          {«£ C           wi i
11
!-- 1
.1Table 3: Benefit Build-up (Birr ,000)1 ksk
1. KOM
1 KSCT
h hs'es*         w>*n*      ■ rents      re» t st H       {K         rfrfrfitf        res «        w«
I «W«         i «• e®       [ mr           •«CT J WOT           *T»«          wot          wot 1 WOT    i J-9OOC     ko«        wot U IKU «          «•«            wn       ws CT
•« ire
trerir
CISXI
■Hill |     ret rei i
wot WOT res w
Kffflf WOT WOE
w ct «■ ct mth
W« WK •csOT
►row
mn
HJSM
■HB'40
WOT
WM
OTS CT
WOT
■CElC
K« CT
ream
re*<M
w ei
rfisof
wot
4t«m
isiBxl
Df/SC res« res os m«
WOT resos
MitCT
tmi>
•erst
►W DC
wgg
WOT
I *■'■ -
rssk
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—
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------ :-
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res
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--------- 1
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w
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Ml El            tun wds            KflOT
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crei ml
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ml              mi
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90S
ml             crei
1ml              mi              mb             ml
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ml             mi
1ml
ere i        i ere b       Iere i
I ere b         Vmi          i ere'i      Jcrei ll ere b       ' ere i         ' ere 1           mi
mi
crei           cm
| ere i          ere b 1 crei          crei , crei         ' crei
KOI
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ml
crei
ere b
crei
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ml
crei
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90S
rtOl OB
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ftttl           real ml             ME I ml             ere i ml             mi mb           crei on            crei crei          mb
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LEQt          MN             IW          ,S4«         jjJDt         ' SiOE        wot           rifle          not
8 S KIS S STable 3: Benefit Build-up (Birr ,000)
Summary
X2? 97QH5
M«29 40.1*
24.9H
t.SM
»«30l
ie wa 402**
wdFinancial Costs ($ million)
I
' TOW           2O0FI
WJ
JtxxJ 1         JVM
j        coif*              8B
20M            MO*          7010           20/1            7012            WJ          20 N           20 13            JOI*        JOJ7        ?0F4
20»fl            7020           2021   3077 35
I O4M cosli 1
Tot>l            1
*251 f         ei oa
25 " I 0.13
40 34                           20 7*         23 81         1772         17 73 j      15 00         u ei         16 86        22 93         2304         1ft 10       B 29
0 13           OUT
1 55           1 84           2 07           2 34           2 80          2 03            2M           3.17           3 47        □ 77
1                 -    ! h.n J
•«,
42.61 I     • 1.10
40,47          22 21 i        2X17          25 17         11.0            11.10        17.33        1*41          1*40         28.11        25.22       15.57      12.08
529       S 01
4 00         4 13
1221      10.53
4 2ft
4.2 S
4 33        4 33        4 33 4.33   “4.33
Economic Costs (Birr million)
7C44
jew i           7007
ZOOJ                7004
7DC5
2004
M10             JOI »                  »rj          «tJ                  JflM|               JOM             X>« •                            MU                MU          MM                  M/r
1 capital co»t* 1 DIM Will
—
104 02       31* 54          4*7.94           302.57        15» *4
1
1*4 52        31* *4         454 *1             303 *5l      1*6 CO
165 53
IO 4*
1*4.31
170 3* j     132 9V        132 W      n 12 4*       103 55       124 32      171 on
12 40                            15 «3
»3 M
17*3         10 57         2121         22 34
1*1,7* 1
140.T*        14* *2      130 01         U* 11        145*3       1*4 33
172 113.24 02 14 02 14
23 *O j       7* 02     ?•   2*     20  00 1*5 53 |    139.25     K> 42 j*  *2.12
44 33
30*1    [   31 *4       32 51 f  32.51            32 SI 0
1          . - _ : 1
--
-
0*7_          0*7            7
7* 24 [    31 54       32 41 f  32. *1      3241 J
11Table 5: Cost Benefit Analysis
Cost Benefit StreamfBIrr million)
2000 1 2001        2002        2003        2004        2005!     2006     2007       2006     2009    2010
2011       20121 2OIJ 201/             2015     2014     2O17[ 2014       20N      20»l      2021  202735
Cott*                          0 00; 184 82    318 54    456 91     303 55      156 60 166 311   IM 76     145 79 148 52  130 01
Benefits        I 0 00                0 00           000          000       -3 42         38 29*102 82   177 35    210 24 220 21   272 50
Net Benefits        0 00 *194 62  *319.54 -456.91   -306.97■121.11 i 43 481 •11.41   63.461 71.69  142.60
12311
145 53 194 33 196 63 139 26 90 42 92 12 75 24  31 Mi 32.51. 32 51
(1
32 51
342 60  416 92 451 62 481 79j 514 18 584 18i 860 50 69J 40i 711 18, 724.77j 735 83        743 SC
21941  273 39 257 50 265 15 374 93 493 76 Ml 39 616 11 579 34 1692.28 703.32
710.99DRAWINGS
FOR
ITANG IRRIGATION PROJECTLIST of DRAWINGS
Drawine
Title
IT-1
IT-2
IT-3 
IT-4
IT-5 
rr-6
IT-7
IT-8 
IT-9 
IT-10 
IT-11
IT-12 
IT-13
IT-14
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 Layoutproject
location
PROJECT LOCATION MAP
□       2C0     400km 111tI
SCALE
MtakdfclB . - _ Ixzfc
-
1:
Flood Protection Dike No. 2
.r .       '. JTrarslllQa- Dralnaoe Layer
60    Stripping    Under Darn *nd_Blankets_
Min. Water , Level EL429.0.
Max. Flood Water
Mormal Wattf*
I »vel El. *316—L -------------------- -
jpervl
Down Strewn Shell
.jjrr
Upstream Impervious Blanket.
1 '-u
HANG DAM
TYPICAL SECTION
MINISTRY of WATER RESOURCES
A DOIS ABABA ETHIOPIA
TAMS - ULG
NEW YORK - LOMDOW - ADO IS ABABA
BARQ-akOBQ MASTER PLMTRREFEASIB1HTY STUD IES
HANG IRRIGATION PROJECT HANG OAM CROSS - SECTION.
Owg
IT - K
19  =
XX
p
X
ILE&UB
_______ Natural GreooO
Crcet of Olka
Wafer Loo I
Canal larart
Secondary Canal offtaka
5=00000!
J-F~
5*000005
« <■>%
Q*tlt»S [ f
M
~~r--»>-»■—
5*0 00005
Q>t93.y,
------------- 1-----------------
S’C O >005
3»DOOO< 5
0«          o=-es-\
■r
55
length in kilometers
"INlSTRT OF WATER R£SOURCES
I
IoiSTjuce unto*ereAs
44»i9T**r ar g**t>
T *«e - rfiiAFARM CANAL
100m
quaternary drain
10 l/s
farm drain
FARM DITCH
10 l/s
10 1/s
10 l/s
10 l/s
10 1/
10 l/s
Quaternary Canal
200m__ _
I-
Im
3m   mln
Variable
Variable_______
I—t-
* Min. Fiee Board
Main Canal = 0 6m
DisUibularies - OJm
SOIL        This Section Is Applicable to
Maincanal and Distributaries
Not to Scale
MINISTRY OF WATER RESOURCES
AOOlS ABABA ETHIOPIA
NEW YORK - LONDON - ADDIS ABABA
TAMS - ULG
BARO-AKOBO MASTER PLAN PREFEA SI BIL 1 TY STUDIES ]
HANG IRRIGATIUI
TYPICAL CANAL SECT
*1 PROJECT
ON ON SLOPE
1
| 4
0»to              October 1996
-------------------------------------------------- -
Dwg No IT- OB J
iCompacted Fill
Roadway
mln
Free board 0.3m mln*
Natural Ground
Compacted Fill
Stripping NO.3m mln
----- 1
varies
Varies
* Mln. Free Board
MINISTRY OF WATER RESOURCES
Main Canal ~ O.Grn
ADDIS ABABA ETHIOPIA
Distributaries -O.3m
TAMS - ULG
NEW YORK - LONDON - ADDIS ABABA
BARO-AKOBO MASTER PLAN PREFEAS IB IL IT Y STUDIES
NOTE Thia Section Is Applicable to Malncanal and Distributaries
Not to 5cale
ITANG IRRIGATION PROJECT
_______ TYPICAL CANAL SECTION ON FLAT TERRAIN
□«l« Octob«f 1fv4
J Qwg Ni> IT-09J
Free Board min 0.6m
River
Stone mln 0.5m Tnick
MINISTRY' OF WATER RESOURCES
ADDIS ABABA HHIOPIA
TAMS - ULG
HtW YOFIK - LONOOH - AOOIS ABABA
Not to Stale
0ARO-AKOBO MASTER PLAN PREFEASIBILITY JTAN6 IRRIGATION PROJECT
TYPICAL PROTECTION DIKE SECTION October 1991Stepdown Transformer j3 KV Power Line
Manhole
Roadway Mln 0,2m. Thick Coarse Base Mln 03m. Thick
River
Compacted Fill
Flap Valve
\
Y
3.5m min
6 m mln
Stone Protection
mln 0.5m Thick
Stoplag Groove ..
MINISTRY OF WATER RESOURCES
AODIS ABABA ETHIOPIA
TAMS - ULG
_________________ HEW TOflK - LOMOON . AOQ1$ ABABA__________________ 8AR0-AKO8D MASTER PLAN PREFEASIBILITY STUDIES
ITANG IRRIGATION PROJECT
TYPICAL DRAINAGE PUMPING STATION AT FLOOD PROTECT ION QIK£
Not to Scale
(kata             October 1t»*
I 0*9 »« IT- «___________________________
Hl JI 11 HDSec ondary Canal 4
QC 4-1-6
Z
QC 5-4-1
LEGEND
424
r-/
Secondary CoU^tor Drain
-423
Main Canal
Secondary Canal ( Distributary)
Tertiary Canal (TC>
Quoternory Canal (QC)
Main Drain
Secondary / Collector Drain Tertiary and Quaternary Drains Check / Control Structure
Tail Scape
NOTES:        I
-Service    Roads,    not    Shown    Are    Located Along , Canals and Pressure Pipes
-On   Farm   Canals   /   Drain   not   Shown -Off Tokei not Shown
MINISTRY OF WATER RESOURCES
ADOIS ABABA ETHIOPIA
TAMS - ULG
MEW YORK - LONDON - ADOIS AfiABA
baro-akobo master plan prefeasibility studies
ITANG IRRIGATION PROJECT TYPICAL IRRIGATION SECTOR GRAVITY SYSTEM
Mo IT-12
-(1) - Control Building
(2J - Service & Mochiner)
/ Pumping Station
Shed
i
LEGEND
Mair? Canal
Secondary Canal
ChecK / Control
Struct
ure
Turn1 out / Off tak
e
Off    take    /    Pu
mping
Station
Drain ( Storm Drain } Solid Set ojr_Movablg Sprinkler System
Burred Pressure Pipe
Center Pivot Sprinkler
with Corner Arm to Irrigate
Circle Plus Corners
Solid Set / Movable Sprinkler System
Building
Secondary Drain
I
NOTES:   I
- Servlet Roads, not Shown Are Located Along . Canals and Pressure Pipes
2 -No Surface Field Drains or Levelling Required
Pivot
Center
MINISTRY OF WATER RESOURCES
AQOIS ABABA ETHIOPIA
NEV YORK MS lomOOH* - ADO IS ABABA
BARO-AKOBQ MASTER PLAN PREFEASIBILITY STUniFC
JANG IRRIGATION PROJECT TYPICAL irrigation sector sprikler system layout
0»t« 5- October
Mo IT-13RESERVED

Summery

Baro-Akobo River Basin Master Plan Summary

Baro-Akobo River Basin Integrated Development Master Plan

Prepared by: TAMS-ULG Consultants for Ethiopian Ministry of Water Resources (1995-1996)

Executive Summary

This master plan evaluates three high-priority water resource projects in Ethiopia's Baro-Akobo River Basin:

Geba Hydroelectric Project (170 MW potential)
Gumero Hydroelectric Project (50 MW potential)
Itang Irrigation Project (53,147 ha irrigable area)

1. Background

The study was commissioned to assess water, natural and social resources development potential. Key limitations included outdated (1977) 1:50,000 scale topographic maps and lack of recent geotechnical data.

2. Geba Hydroelectric Project

Key Features

Location: 60 km east of Gore on Geba River
Components: Storage dam + two downstream power plants
Capacity: 112 MW (Diversion 1) + 72 MW (Diversion 2)
Annual Energy: 962 GWh (firm)
Reservoir: 66 km² area, 792 mcm active storage

Economic Analysis

Metric	Value
Construction Cost (1996)	$252.76 million
Energy Cost	$0.038/kWh
Internal Rate of Return	16.4%

3. Gumero Hydroelectric Project

Key Features

Location: 27 km west of Metu on Gumero River
Staged development potential (12 MW + 18 MW + 20 MW)
Annual Energy: 271 GWh (firm)
Reservoir: 37 km² area, 244 mcm active storage

Economic Analysis

Metric	Value
Construction Cost (1996)	$99.78 million
Energy Cost	$0.049/kWh
Internal Rate of Return	11.4%

4. Itang Irrigation Project

Key Features

Location: 30 km west of Gambela on Baro River
Net Irrigable Area: 53,147 hectares
Main Crops: Sugar cane (40%), diversified rotation (60%)
Water Source: Itang Dam reservoir (139.4 mcm active storage)

Project Components

Component	Description
Main Canal	53 km long, capacity 10.5-58.5 m³/s
Secondary Canals	12 canals, 87.3 km total length
Drainage System	Main drain (13 km) + secondary drains (79.7 km)

Key Recommendations

Proceed with feasibility studies for all three projects
Conduct updated topographic surveys and geotechnical investigations
Prioritize Geba Hydroelectric Project for ICS integration
Develop Gumero Project in stages matching regional demand
Implement Itang Irrigation with phased sugar cane development