FEDERAL DEMOCRATIC REPUBIJC OF ETHIOPIA
MINISTRY OF WATER RESOURCES
BARO-AKOBO RIVER BASIN
INTEGRATED DEVELOPMENT
MASTER PLAN STUDY
FINAL REPORT
YOLUME V
PREFEASIBILITY STUDIESFEDERAL DEMOCRATIC REPUBLIC OF ETHIOP14 MINISTRY OF WATER RESOlfRCES
baro-akobo river basin integrated development MASTER PLAN STUDY
VOLUME V
PREFEASIBILITY STUDIES
TAMS-LLG Bam-Akobo River Harin integrated Development MatierPiaiiINDEX OF VOLUMES AND ANNEXES
Volume I:Executive Summary
Volume II:RESOURCE BASE AND DEVELOPMENT OPTIONS Volume ni:..MASTERPLAN DEVELOPMENT
Volume IV:Project Area Maps
Volume VPREFEASIBn.lTY STUDIES
ANNEXES
I.         WA TER RESOURCES
Annex 1 A..             Climatology Annex IB Hydrology
Annex IC                  Flood Studies
Annex ID
Annex IE
.Annex IFSediment Studies Annex 1G
Annex IHIrrigation Projects Annex II
GroundWater
Reservoir Operation Studies
Water Resources Cost    Estimating Water Supply Projects
Annex 1J............................................. Hydropower Projects
2.        NATURAL RESOURCES
Annex 2ALand Evaluation
Annex 2B
Soils and Soil Conservation
Annex 2C............................................ Geology
.Annex 2D  Mineral Resources Annex 2E.              . .. Forestry Annex 2F  Wildlife
Annex 2G . ,
Annex 2H                       Apiculture Annex 21       Agriculture
Annex 2J.. Renewable Energy Annex 2K
Tourism
Fisheries
Annex 2L..
.........................Livestock
& SOCIO-ECONOMICS
Annex 3 A
Annex 38
.Annex 3C
Annex 3D
Annex 3E........
Annex 3F  ...........................
< ENVIRONMENT
.Annex 4 Environment
 T
Population Aspects
Socio-Ethnic Groups Analysis Economic Infrastructures
Social Infrastructures
Economic and Financial Analysis Institutional Support
AMS-L'LG Baro-Akobo River Basin Integrated Development .Master PlanPREFEASIBILITY ST IT) IE S
VOLUME V
VOLUME V PREFEASIBILITY STUDIES
TAMS-ULG Baro-Akobo Rher Basin Integrated Development Master PlanAPREFEASIBILHY STUDIES
VOLUME V
CONTENTS
1
I  I Master Plan Studies ........................ 1.2  Selection of Candidate Projects 13 Study Limitations .............................
2. GEBA HYDROELECTRIC PROJECT
2   1 Introduction
...... .......—............................................. .............. ......................
4
2.1.1    Project Concept.................. .........................................................................................
2.1.2    Project Area.................................................................................... ...................... ..............
2.1.3    Power Planning............................................................ ...................................... ................’
2.2   Basic Data ...................................................................................................................................
2.21 Topography................................................... -........................................................................
2.2.3 Site Geology................................................................................ ........................................... 7
2  3 Project Development................. ............. . .......................... -...................................... ............... 7
2.3.1 Project Options....................................................................................................................... 7
2.3.2    Reservoir Operation Studies..... ...................... ............ .. .................................... . ........... - 8
2.3.3    Access and Transmission Lines....................... ......................................... . .................... 10
2.3.1 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 ...............................
3.7. / Project Concept....................
3.1.2 Project Area...................... 3.1.3 Power Planning.................
3.2 Basic Data........
3.2.1    Topography 3.2.2    Hydrology...
25
.25
.25
.25
.25
.26
.26
.26
3.2        3 Sire Geology............. ............................. .................. .................................................... 27
27
3  3 Project Development................... .................................................................................... 28
3.3.1    Project Options,,................. .................. _.................. ................... . 4................................ 25
3           J. 2 Reservoir Operation Studies....... ....... . .................. +..................... . ......................... 25
3.33 Access 
................................................. ..... w
3.14 Project Layout...^................... ...T........................................... . .................
3 3.5 Project Selection and Optimisation.................. ................... .. ......................... ............ . J/
3.4 Environmental Assessment................. . ............................................... 34
3 5 The Recommended Project................ ............. 40
3.5        1 Project Description............................................................”............. 40
3.5.2    Quantity and Cost Estimate..... ......... ............ 42
TAMS-l'LG BAkobo Rjvcr Batin Integrated Development Master Plan
iPREFEASUBILITY STUDIES
VOLUME V
TABLES
Table 2 I     Average Monthly Flows at Geba Dam (m /s)............................................................ 6
Table 2 2    Flood Frequency Analysis at Geba Dam................................................................... 6
Table 2.3    Probable Maximum Precipitation................................................................................. ...
Table 2 4    Geba Reservoir Firm Flow (m’/s).............................................. .....................................
Table 2.5 Monthly Flows at Geba Dam (m’/s)....................................................................................
Table 2.6 Geba Hydroelectric Project - Annual Firm Energy (GWh)................................... ... jq
Table 2.7 Project Optimisation Reservoir and Power Plant Characteristics................................. . |
Table 2.8 Project Optimization Cost Estimates (USS ,000)..................................................... 13
Table 2.9 Project Optimisation - Internal Rate of Return................................................................
Table 2.10 Unit Prices (January 1996)..................................................................................... 22
Table 2 11 Geba Hydroelectric Project Cost Estimate (USS - January 1996)............................. 23
Table 3.1    Average Monthly Flows at Gumero Dam (m’/s)................................................... ...26
Table 3 2    Flood Frequency Analysis at Gumero Dam.............................................................. 27
Table 3.3    Probable Maximum Precipitation..............................................................................27
Table 3 .4   Monthly  Flows at Gumero Dam (m’/s)................................................................... 29
Table 3.5    Gumero Reservoir Firm Flow (m’/s)........................................................................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
Table 4 7    Hours of Sunshine Per Day.................................................................................  50
Table 4 8   Potential Evapotranspiration and Lake Evaporation (mm)     . . ......................... 50
Table 4.9     Mean, Monthly and Annual Flows........... .......................................................... 51
Table4.10    Annual Flow Variation........................................................................................ 51
Table 4 11   Maximum Instantaneous Water Level Elevations (masl)....................................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 (m'/s per 10,000 hectares) .
61
Table 4 17   Unit Costs (January 1996) ............... ...
............................................. 65
Table 4 18   Itang Irrigation Project Cost Estimate - US Dollars (Jan 1996).......................... 68
Table 4 19 Itang Irrigation Project Annual Costs - 1000 USS (Jan 1996)............ ... ..............69
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 Birr)............................................................................. 72
TAMS-ULG Baro-Akobo River Basin Integrated Development .Master Planprefeasibilitv studies
5.5. J Implementation Schedule...................... ......
3 6 Economic Appraisal. ............................................
4.     IT A NG IRRIGATION PROJECT........................
4.1   Introduction .................. ............................................
4.1.1    Project Area........... . ........................... .............
4.1.2    Institutional Setting ......................... . .............
VOLUME V
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...............................
4.2.6    Land Resources.............................. . ................
4.2.7    Geology and Geotechnical................................
4   3 Project Development .................................................
4.3        I Agriculture and Cropping Patterns................
4.3.2    irrigation Water Requirements..........................
4.3.3    Reservoir Operation Studies..,..................
4           3 4 irrigation Infrastructure........ ......................
4.3.5     Estimates of Costs and Benefits .....................
4   4. The Recommended Project...................................
4.4.1    Project Description............... .......... .................. 4.4.2    Cost Estimates..........................................
43
44
.45
....... 45
....... 45
....... 46
....... 46
...... 46
...... 46
...... 51
......52
.......52
...... 53
...... 56
....... 56
....... 56
....... 58
......6!
...... 61
...... 64
....... 65
...... 65
.......67
4.4.3    Implementation Schedule............................................. ................. ..............................67
4.4.4    Economic Analysis....................... ......................................... ........ . .................................. 70
4.4.5    Environmental Assessment.............. ............ . .,................................. . ........................ .....72
APPENDICES
Figure 1 1 Project Location Map
.80
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 1 Gross Monthly Irrigation Water Requirements for Sugar Cane-Diversified
Cropping
Figure 4 2 hang Reservoir Area-Capacity Curve Figure 4 3 hang Irrigation Implementation Schedule
TAMS-ULG Baro-Akobo Rher Basin Integrated Development Muter Plan1PREFEASIBILITY STI dies
VOLUME V
1.          BACKGROUND
1.1 Master Plan Studies
This  volume contains  the prefeasibiiity  reports  for three water resources  projects components  of the Master Plan for Integrated Development of the Baro-Akobo Rtvi is one of twelve regional Master Plans commissioned by the Government of Ethiopia it development potential of water, natural and social resources of the country
which are
ir Basin It
> assess the
The Water Resources Development Authority contracted this Master Plan study to the association ofTAMS Consultants, he of New York  and ULG Consultants  of Warwick, U.K., in June 1995; the studies were initiated in July 1995 and were completed in November 1996
In accordance with the Terms of Reference for the Consultancy Services, the study shall include the following
A review of the existing database,
•     A portfolio of prioritised development projects,
•     A Master Plan for the integrated development of the Basin,
•      Information  and  data  required  for  co-operative  development  undertakings  with  downstream countries and,
•     Prefeasibiiity 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 prefeasibility' level studies (Figure 11) They' are
the Geba Hydroelectric project on the Geba River, located approximately 60 km east of Gore in the upper reaches of the Baro basin,
the Gumcro Hydroelectric 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 Gambcla and an irrigation area on the right bank in the vicinity of Itang
1 AMS-ULG Baro-Akobo River Burn Integrated Development Mailer Plan
1
Chapter ]GUU£NO-J 21 U*
ITANG* DAU IjANG
G£BA DAU
/
MINISTRY OF WATER RESOURCES
ADO'S ARAB A ETHIOPIA
TAMS - ULG
NEW YORK - LONDON - ADOS AR AB A
BARO-AKOBO MASTER PLAN PREFEASIBIUTY STUDIES
BASIN MAP
4CXm
z
Date:                                                  | Figure No 1-1t:PREFEASIBILITY STUDIES
VOLUME V
1.2 Seleclion of Candidate Projects
The Master Plan studies have included the appraisal of a number of water resources projects in the BaroAkobo basin Overall, 22 dam projects, 19 hydropower plant projects  and 14 imgation schemes have been reviewed
With regard to the hydropower potential of the basin, it is clear that the large and medium-size projects are too large for the anticipated growth of electricity demand within the basin which is expected to reach 61 MW in vear 2020 These projects must be justified within the context ot the Interconnected System (ICS) The Master Plan studies, detailed in Annex  1J, have ident.ficd several projects with attractive economic returns
In the ranee 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 at rhe location of steep reaches of the river
Both projects, therefore, present the possibility of staged development if the economic and/or financial conditions dictate such an approach In this case, the Geba project would be preferable since the two stages of development (100 MW and 70 MW) would be in the medium-size range With the 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 MW power plant, the latter being already a large-size project Furthermore it appears from the only available topographic map, dated 1977 al 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, al the present die 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 1 J) have identified several small-size projects that would be suitable to meet that demand Among them it appears  that the best-suited scheme would be a staged development of the Gumero project. The Gumero project, similarly  to the Geba and Baro, consists of a regulating reservoir in the upper reach of the Gumero River and three power diversions m cascade downstream of the dam taking advantage of the steep profile of the river The Gumero project’s  ultimate development would be approximately  50 MW, at three power plants  of 12 MW, 18 MW and 20 MW respectively  If the decision is  taken to implement this scheme, and to follow the demand for power in the basin, the first power plant could come on Line by year 2005, the second (18 MW) m year 2012 and the third (20 MW) m year 2018 The project cost appears  to be significantly  lower than the alternate sources  of electric power in the basin which are mainly isolated diesel plants
With regard to the irrigation project, the Master Plan studies  indicated that completion of the ongoing Alwero Abobo dam project should be given first priority Thereafter three other projects were selecied for consideration in the Master Planning These are the hang Imgation project on the right bank of the Baro using gravity feed from ltang Dam, the upstream Alwero project fed by gravitv from Dumbong dam. and the Gilo-2 right bank project fed by gravity from Gilo-2 dam
The hang project stands out as being the most economically viable.
TAMS-ULG Barn-Akobo River Buin Integrated Development Muter Plan
Chapter 1prefeasibility studies
1J Study Li mi tit io ns
When the three projects for prefeasibihty level studies were identified in the course of the
Plan studies, it was clear that additional site data would be required to dev elop the projects to p prefeasibility level In particular for the Gumero and Geba hydroelectric projects, the topographic data available were the 1:50,000 scale maps, dated 1977 To meet the requirements the following field work was requested at each project area from WRDa, u provided for under the consulting services agreement
a map of the reservoir areas at a 1110,000 scale with 5-metre contour intervals,
a topographic map at a 1:2 000 scale with 2-metre contour
r
intervals at the location of at
the structures, and
cross  sections  along  the  alignments  of  power  canals  at  an  approximate  rate  of  ihrer sections per kilometre
It was also recommended that provision be made to perform a number of test pits, preferably one at each structure location These lest 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 1:50,000 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 c.. 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 regulate 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 significantly for an adequate assessment of the civil work required and to better define the quantity and cost estimates
1AMS-ULG Bmro-Akoho Rjver Burn In.egret,  Develops Metier Plat,
d
Chapter 1
JPREFEASIBILITY STUDIES
VOLUME V
2.         GEBA HYDROELECTRIC PROJECT
2.1 Introduction
2.1.1 Project Concept
In Lht review
hydropower projects
of  the  hydropower  resources  of  the  Baro-Akobo  basin  (sec  .Annex  1J),  several uiuiccts have been identified that have the potential of providing low cost energy' and
power to L„----------
the interconnected system (ICS) The most promising of these is the Geba hydroelectnc
.
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 J, 2 Project Area
The project is  located  on  the  Geba River  about  120  km  upstream  of its  junction  with the Biibir 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 2500 At the site itself the river is at elevation 2130, falling to 1840 and 1500 at the powerhouses for Diversion 1 and Diversion 2 respectively 
2.1. J ftouw Ptanni ng
Al present the existing countrywide generating capacity  of approximately  400 W serves  a total population of 57 million people. Of this  total capacity, the installed capacity  connected to the Inter Connected System (ICS), which does not serve the whole country, is 385 MW. The
TAMS-ULG Baro-Akobo River Baiin Interned Development Muter Plan
Chapter 2PEAK POWER DEMAND (MW)
3000
2000
1935
2000
2005
YEAR
2010
EELPA PEAK POWER
demand FORECAST
Fiflure 2-1Firm Flow(m3/s)
Geba River at Gcba-A Dam Site
Yield Curve at 98% Reliability
Figure 2.2Elevation In maters
Area In km2
Legend
— — >nrt»8l
------ — After Seimentat on -----------------—-----
_
Geba Reservoir
Area-Capacity Curve
Figure 2-3PREFEASIBIIJTY STUDIES
VOLUME V
population is  estimated to be growing at an annual rate of 3%. In recent years, since the implementation of a comprehensive program of economic  reform following the drought and avil war of the 1980s. the economy  has  recuperated and is  now growing at an annual rate of 7% a year
ambiiious   program   of   power   generation   development,   both   hydropower   and   thermal,   is planned  to  meet  the  erowth  of  demand,  taken  by  EELPA  to  be  at  an  annual  rate  of  10%  a  year
It  is  estimated  that  approximately  1800  MW  of  generating  capacity  needs  to  be  commissioned over the next 20 years to satisfy the growth in demand, as is illustrated in Figure 2-1
The hydroelectric  power studies  performed for the purpose of this  Master Plan (Annex  1 J) have shown that the Geba Hydroelectric  Project could be a candidate to be integrated 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 River, consists  of a total of 10 stations  and only  two stations  having more than twelve years  of records  These are on the Baro River at Gambela and on the Sor River at Metu where the catchment areas are 23,461 km‘ and 1,648 km; 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  the 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 Bniin lnrejrated Development Muter Plan
5
Chapter 2FrOTASIBILITY STl’DIES
V0LVMt
v
T.bl« 2.1 Average Monthly Flow, .<                    »*■"J>9 8_
January February March April Mas
72
40
July
August
..
95.7
September
110.0
2.5
39
October
659
—
November
21.0
28.2_______________
December_________ __  9.8
The mean annual discharge is 35.7 m’/s or 1,127 mcm with a strongly pronounced seasons variation 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 t0 determine flow for different return periods at the Geba site The results of this analysis, (Anna 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
June
Return Period
J
Discharge (m /s)
10 vear
292
100 vear
462
500 vear
631
For the meteorological and rainfall gauging stations located in the vicinity of the basin, a statistical analysis   of   the   maximum   daily   precipitation   was   performed   Applying   the   Hershfieid 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 2-3.
Table 2.3 Probable Maximum Precipitation
S titions
24-Hour PMP (mm 1
Chora
377
Gore
400
Metu
336
Hurumu
501
Based on this analysis the 24-hour point PMP for the Geba catchment area was estimated to be 400 mm For the purpose of this prefeasibility study, a simplified HEC-1 model was developed w STTom^0* hvdrOgraph ofthe spillway des«  The peak discharge is estimated
n
XZe«
sed.mentat.on estunate for all renewed reserves is 
forT^^       5ed,mCTt          “       the          Vncinity          Ofthe          SIte          A       discussion       ofthe
presenled in lf t0 the Mastfr Plan
TAMS-VXG Baro-Akobo River Baiin
Chapter 2
6prefeasibility studies
VOLUME V
Report  For  the  purpose  of  planning,  the  reservoir  operation  studies  considered  the  accumulation of sediment in the reservoir at an annual rate of 1,320,000 nr*.
2.2.3    Site Geo tog)
The damsite is  located on Basalt The ARDCO-GEOSERV geological sketch map of the area shows  Alluvium over Mekonnen Basalt over hornblende and biotite gneisses  At the dam site, alluvium overlies  the basalt foundation The site is  located right at the comer of available aerial photos  strip 16, photo 1323, and is  not stereoscopic. The whole area is  forested with gentle relief and rolling country  Rock  is  likely  to be far below the surface, although downstream of the dam siic  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  rcckfLU  quarry  The  clay  on  the  hill  slopes is  reputedly  suitable  for  impervious  fill  Due  to  the  lack  of  rock  an  earthfill  dam  is  recommended The north-south fault near the dam axis to the east shown on the sketch map must be investigated
Sand  and  gravel  is  found  in  the  Geba  flood  plains  A  diversion  tunnel  should  be  easily  constructed in  basalt  with  support  of  shotcrete,  wire  mesh  and  rockbolts  The  canals  for  diversions  1  and  2 are  likely  to  be  partly  in  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 w ere performed, it could indicate that a rockfill should be considered Under such conditions  a concrete-faced rockfill might also be an attractive alternative, since, with a maximum height of 45 metres, it is  within the range where concrete-faced rockfills arc economical
Aenal photographic  interpretation indicates  the existence of a north-south fault on the right abutment at the site Consequently  the spillway  has  been positioned on the left abutment, where the topography  requires  a long, concrete-paved chute leading to a stilling basin at the edge of the river some distance downstream. If a field survey  were to indicate that this  fault would present no hazard to a spillway  constructed on the right bank, this  would result in a much shorter chute this option should be considered after further investigation
With a 275-metre head available at the end of a 3.500-metre long canal, and considering a drainage area of over 1,100 km\ a first-stage run-of-river development at the Geba I Diversion sue might be considered With an 80% probability  flow of only  3.5 m’/s, it is  not considered economically feasible, but depending on other development options in the basin, it could be worth
1AMS-U1G Baro-Akobo River B^sLn Integrated Development Master Plan
Chapter 2pREFEAsreurn' sn'DEs
V0L%
W
noted. the o*’he^X^
^ kX  X^»— whenmore detailed, and larger Le.
S«XXv-be.ta. a more economical stte can be found, or .„
X«onom.eal arrangement of stores and layout can bo made
23.2 Reservoir Operation Studies
As  indicated  above,  the  reservoir  will  regulate  the  river  flow  to  be  used  at  two  downstrcj3 hydroelectric power plants The HEC-5 computer model was used to estimate the yield, Or flow, that can be guaranteed by operating the reservoir so as to release a constant flow. Forth, purpose of this study, the yield was defined as the constant monthly discharge for which the long, term average deficit is 2% of the yield (98% reliability) The HEC-5 model performs a monthly routing of the 74-year long flow time senes at the dam site Figure 2.2 shows the yield in mJ/t of the Geba River at the dam locanon 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 sediment*: reservoir was determined by the use of the methodology' developed by Borland, Miller and Moody Table 2 4 shows the firm flow at 98% reliability for the four reservoir levels selected for optimisation of the Geba project Figure 2 3 shows the area capacity curves resulting from this computation for the reservoir with a maximum operating level at El 2,170 Table 2 5 shows the 74-year long flow time series used with the HEC-5 program
Table 2.4 Geba Reservoir Firm Flow (m /s)
3
Maximum Reservoir Level
Active Storage (mem)
Firm Flow(m 7s)
El 2160
290
204
El 2165
502
El 2170
27.2
792
El 2175
31.1
1,183
32 8
, W lc>crvoir levels, cne hrm energy generated annually by the project was 
tad?Xl»Zfb T °f85%' rwoeetivelv TaSI ’T'
of‘•/•The p0 "'" dlv!rsl0"s ■» 275 metre and 175 metre
fan ""w p""a"d lha
f “' “oh »r th.
TAMS-vu;
Chapter 2
8Tab* 2-6
Monthly Ftowv *t Gcba Dam (mS/aacJ
2D          46           1.9
Apr
23 39 46
JVHl               JMl
171           47.4
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IB 44 95
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21           24           3.6 1.0          1.4           41 10           23            10 21            It             2t 22           24           1.1
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25           19            56
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24           7,6         15.5
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1.5          61 9          f«2             m.2           74 4         1B0           19
208           414           913         iSfl.O           518         24 7        11 4 141           503           W»            417            125           53            19 418          94 1         11L1          1023           45 1         14 D           8fl
05        105 2        127.5         1030           596          223           B2
379           841         1W 1          1177           99 1        31JJ           62
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17 2           47?           913            639            M1            69           7 4
251           620          94 1         1424            972          4«1         18 1
107 0         1X4          104 4           904          227            93
245           89»           920          1M2            950          470          177
14          81.0        108 fl          81.1            715          15#            97 4 4           159           <24           130              IS            14            12
(DO         104 4          t»5           1023           504         221           fl 1 84          24 0           UO         1S2C            we          213          10?
204           736          57 7           5C2           18 I            75            97 440        108 0        128 4         1438           803          224            92 427           MO         1131         1044            MO          143            5?
41 1           S25        100 1         1005            M2          13 0            85 1 4           607         1082           807           ?3 1         117            97
42 *           Mfl          irzfl.         103 9           *57         14 2           87
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4tf           836         1105         101 S           444          140           0.5
292           409          70 7                            81.9         117            52
17.1           474           907           634            389           SB           73
15          ■1 7        >07 9           520           742          193            »0 13          Bi 5         ■M-2          B2_2          74 4         190            99
2D I <36 91 3 1500 <3 B 247 11 4 U3 501 »9 41 7 US 53 39
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37 9           MB          1®1          117.7            »1           210            62 244           NS           61 7         138 7           M0          468         17 8 172           >05           892           78 3           <07         12 B           59
2S 1           920          94 1         1424           87 2         Al 1        18 1 146          638           547         105 5          6« a         283            96
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17.4          58.8          07 0         2294          1534          415         20 6 458           712         1022         131 0           WB           »5          18.9
238          BB 8         88 6         1340           01 3         45 3         17.0
1S9           572           B52         2233          1588         401            »0
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484          785         IC1 1        129 9            M2          30.3         187
Z2B 135 K5 129 3 849 4J.7 184 295 Mt 109.0 •70 2B 0 242 92 37 6 TIB 1161 ’73 B 70. Q 154 56
103 1         174.1         ZZ20         Z235            867          ma            40 345           636           644         109 0           96.6         282            05 352          81.1        108 B           851            348          775            Iflt
2Q8 43 a 11 7 1586 M 1 247 114 414 07 8 lasi 1037 61 1 '4 9 94 176 47.2 7ns 70 6 4! 4 130 SB
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AhhuBI
25.72
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37 01
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35 ’OPREHLASlBtUn STI DIES
Tibtr 1.* Crfbi Uydrotlrdric Projtti - Annual Firm Energy (G\Vh)
2.X J .4«tm an J Tranimurwn Una
.Ai  preMoush*  noted.  the  main  storage  dam  at  Geba  is  located  18  km  south  of  the  Metu-BedeJe road  wtech  is  also  the  main  access  road  from  Addis  Ababa  Al  the  present  ttme,  there  is  no  r«d access  to  the  sic,  or  to  other  of  the  diversions  However,  the  Geba  2  Diversion  Powerhouse  B lew  than  Vi  fan  from  the  road  Access  to  the  sites  farther  south  will  require  pioneering  road  work, with  a  total  route  mileage  probably  well  in  excess  of  18  km  Eventually,  the  power  canals  for  the two diversions (a total of 9 5 km) could be pan of the permanent access, but whether these could be constructed as part of the construction access must await a more detailed route survey
Al the present time, the doses: point on (he ICS to the Geba Project is  at Jimma, 140 road kilometres  on the Metu-Bedde-Jimma highway, or 100 kilometres  overland However, it is  noted that there are plans  to extend the ICS to Bedele, only  25 km away  by  year 2000 In the other direction, the existing Sor-Metu-Gorc-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  J  80 km from the pow er 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 flows.
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 spillway on the right abutment, a location which otherwise, topographically, would be more favourable as  the required spillway  chute would be much shorter With the spillway  located on the left abutment, it appeared to be more appropriate to put the diversion tunnels on the right abutment They will cross  the inferred fault near the downstream portal, but at depth An allowance for additional tunnel support at this location has been made in the cost estimate One of the tunnels will be used for making releases to the power projects downstream, and since a multilevel outlet is required for environmental reasons, locating the tunnels on the right bank avoids interference between the outlet tower and the spillway intake.
TAMS*ULG Baro-Atabo JUvr r Bailn Integrated Development Muter Plan
10
Chapter 2pREFEAsrenm studies
VOLUME V
The two power diversions  are located on the left bank, at the heads  of falls. where contour corah of minimum length can be constructed to feed very  steeply  sloping penstocks  leadmg to the nowerhouses  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. J. 5 Project Selection and Optimisation
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  prefeasbility  study, the project- installed capacity  has  been selected to provide a project plant factor of approximately  60% This plant factor will require optimisation at the feasibility  or design stage This  plant factor is  close to the system load factor which is adequate to provide a fair evaluation of the project
The two hydropower diversions  downstream of the storage dam. are essentially  run-of-rrvtr projects  utilising the 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 not depend on the head created by  the storage dam. the minimum reservoir operating level is  selected as  the minimum technical and environmentally  feasible, taking into account the estimated sediment deposit in the reservoir over the life of the project On that basis  the minimum reservoir level selected is  at El 2145 Tabic 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
2 J 70
2175
Avg Regulated Discharge (m 7s)
20.4
27.2
31.0
32.8
Max Power Discharge (m 7s)
34.0
45.3
51 7
54 7
Diversion No 1 Head (m)
275
275
275’
275
Diversion No 1 Capacity (MW)
73
98
112
118
Diversion No 2 Head (m)
175
175
175--------------
175
Diversion No. 2 Capacity (MW)
47
62
71
75
The cost estimate for each of these projects  was  prepared in accordance with the methodology- established in .Annex  1G, Water Resources  Cost Estimating of the Master Plan A summary  of the major cost items is shown on Table 2.8
The project size selection was  made on the basis  of the highest internal rate of return (TRR), taking into account the feasibility  study, design and administration costs, the cost of construction allocated over a period of four years, the cost of operation and maintenance and the revenue from the sales  of firm energy  At the feasibility  level the optimisation will be done on the basis  of the incremental IRR.
TAMS-ULG Baro-Akubo River Bum Integrated Development Muter Plan
II
Chapter IPRE FEASIBILITY STL DIES
As shown on Table 2 8, the cost for engineering and administration of the project h> coruted at 10% of the total construction cost
The cost of operation and maintenance over the 50-star life of the project were » follows 
V °LVMEv
b>.
'^'natedj.
0 5% for civil works
2 5% for electromechanical equipment
1 0% for transmission lines
Revenues from the sales of firm energy were estimated at the rate of USS 0 06/k Wh (Janu^ 1996)
TAMS-ULG Barn-Ak*bo Rkvtr Lnu^mtcd Development Muter Plin
12
Chapter 2
vTable 2.8
Project Optimization - Cost Estimates (USS ,000}
Price Level: January 1996
[Max. Nor. Res. Level
_
.
EL 2t160
EL2J«
EL 1,170
El. 2,175
[Div. No. 1 Inst. Cap
73 MW
M MW
112 MW
118 MW
IOiv. No.2 Inst. Cap
47 MW
62 MW
71 MW
75 MW
3.061
Dam & App. Worts
Preliminary
Low Level Outlet 250 250 250 .
3 569
4,194
4 956
Main Dam
12.219
15 602
19,772
24 Bsi
Access Road
2600
2.600
2600
2 600
Diversion Tunnel
2421
2.421
2421
2 421
Spillway
2.918
2 918
2 915
2.918
250 j
Subtotal 23,469
Power Plant S Conveyance
Diversion No. 1
27,380           32,154            34,008
preliminary
6 166
7 597
3 657
9272
Access Road
348
345
345
348
Power Intake
0
0
0
0
Power Canal
7476
7 478
7,476
7 476
Power Tunnel
0
0
0
0
Surge Shan
0
0.
□
0
Pressure Shaft
0
0
□
0
Penstock A Manifoki
3,485
4,643
5 300
5808
29 930
45 920
Powerhouse A Equipment                                                    40 180                                   48 380
Subtotal 47,425
Diversion No. 2
60,544           67,501           71,084
Preliminary
4,467
5.569
6229
6 522
Access Road
80
80
80
80
Power Intake
0
0
0
0
Power Canal
6 729
8 729
6 729
6 729
Power Tunnel
0
0
0
0
Surge Shaft
c
0
0
0
Pressure Shafi
0
0
0
0
Penstock A Manifold
1.118
1.490
1,700
1,798
Powerhouse A Equipment
21 655           28,830
33.015
34.875
Subtotal 34,249
42,698           47,752            50,004
Transmission System
Preliminary
5265
5.307
5 331
5.342
Switchyard Div, No1
1,006
1,163
1,250
1.288
Switchyard Div. No2
842
967
1.042
1.075
Transmission Line
33 250
33.250
33,250
33.250
Subtotal          40,363           40.687           40,873           40.954
Reservoir Area Clearing
2.160
3.054
3,948
5,508 |
[Population Relocation
700
700
700
700
Subtotal
148.366
175 043
193,328
206,258
Physical Contingencies (20%)
29 673
35.009
38.666
41.252
Engineering & Administration (10%)
17.804
21,005
23.199
24.751
I
Total Direct Cost| 195,843 | 231,056 | 255,193 f 272,260 |PREFEASIBHJTY STI DIFS
on .h~ Tibfc2q
‘XIRR °f ,bt fo"
KhOTCS WCTC C°mP“,ed sh»u, „
Tible 2.9 Project Optimisation - Internal Rate of Return
Maximum Reservoir Lnd
El 2160
El 2165
El 2170
El 2175
Diversion No I Inst Cap
Dn croon No 2 Inst Cap
73
47
98
62
112
71
US
75
Total Construction Cost (USS mil)
195 S
231 9
255 2
272 J
.Annual O & M Cost (USS mil)
2 80
3 49
3 91
4 12
Firm Encrg) (GWhyT)
631
841
962
1,014
Annual Rr-erruc (USS mil>
37 86
50 46
57 72
60 84
1RR '.1________________________
14 4%
16 0%
16 4%
16.3%
On that basis, the Geba project with a maximum operating pool at El 2,170 was  selected The number cf units and the unit size were selected based on the fact that, at the present, the largest unit sue in the ICS is  approximately  30 M\V and that the total installed capacity  of the Geba projeci 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 sue Hence, the power plant al Diversion No I 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 Dhibabor region near the eastern edge of the Master Plan area, on the Geba River. 120 km upstream of its  confluence with the Birbir River Its  geology  is composed of faulted basalt in combination with other rocks  overlain by  alluvium Its  landscape is rolling, its vegetation forest
The dam would be 45 metres high and 475 metres long It would discharge water into the Geba River, where two in-line diversons, power canals, and powerhouses  would use its  flow to generate electricity  The first diversion is  4 km downstream of the dam. the second 17 km The respective lengths of their power canals are 3 5 and 6 km.
Geba reservoir would cover an area of 90 km , its watershed covers 1,086 km . Mean annual
2
2
3
flow at Geba dam sue is estimated to be 35 9 m /s or 11,300 MCM per annum Its normal
maximum operating level would be 2,170 m, its minimum 2,145 m, a difference of 25 m
Maximum capacity of the reservoir, including dead and live storage, is 865 MCM The average residence time of water, computed by dividing storage by annual flow, is 0 91 month on the
average, the reservoir would replace its water about 13 times per year
Positive impacts
This  section  discusses  the  potential  non-hydroelectnc  benefits  of  the  project.  Potential  positive impacts include flood control, reservoir fisheries, fuelwood and recession agriculture and grazing
TAMS-ULG Bare-A kobo Rhtr Buin Uletnud Btxek.pmeoi Mauer Plan
M
Chapter 2prefeasibilfty studies
VOLUME V
FhrsJ  conrrof A flood surcharge volume of JOO million cubic  metres  t mem) is  provided Flood attenuation will undoubtedly  occur as  a result of normal reservoir operations  However, flood control is  not the primary  purpose of the reservoir, and based on the review of the 1 50.000 wale map. it appears there is practically no settlement an the Gumero and the Ofa riven
R.'wr.v<r   fisheries   Neither   the   study   by   Selkhozprom   export   nor   ARDCO-GEOSERV   provides fisheries   estimates   for   impoundments   in   the   upper   basin   Seikhozpromexpor:   (1988)   estimated that  the  Abobo  reservoir  in  the  lower  basin  could  produce  an  annual  catch  of  100  t  for  its 2   210   hectares   reservoir   This   result   cannot   be   extrapolated   to   upland   reservoirs,   however, without further study
Fuef^ood 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
UsiriE  his  results,  the  reservoir  lies  in  an  area  whose  potential  dry'  woody  biomass  lies  between
1
30  and  50  t/ha  For  the  area  of  the  Geba  reservoir  (66  km ),  this  translates  into  a  potential fuelwood  supply  of  between  tonnes  At  5  Birr  per  20  kg  bundle  of  Riel  wood,  its  gross  resale value,  exclusive  of  the  cost  of  collection  and  preparation,  is  between  49  5  and  32  5  million  birr (USS 7 9 and 13 2 million)
Recession agriculture and grttcing The reservoir offers  the potential for recession grazing and agriculture dunng the dry  season Poorly  drained areas  have been traditionally  used for dry  land 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  tn 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 ofa 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   the following
Construction camp, Roads, and
• Dam and appurtenant works, ' Dislocation of people,
■   Loss of land
TAMS-tLG Baro-Akobo River Buio Integrated Development Muter Plan
15
Chapter 2PREHASIBILITY SHIMES____________________________________________ V
•     Lob of histone or ether features.
■ Lob of wildlife habrtal
Proliferation of aquatic weeds,
•     Deterioration of "Her quality,
•     Reservoir sediment atio A
•     Rjvennc fisheries.
Water-related diseases,
•     Conflicting demands for water, and
irxreasrd land ptessire
Construction camps usually comprise quarters for between 200 and 600
ind cecum showers. cooking facilities, toilets, generators, fuel dumps, cement machines, parking
areas - everything needed by a small town Their design is usually temporary , although then
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 extea possfcle. 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 limber 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 rhe 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 U
required, otherwise, extensive septic systems might be permissible
The construction of the Gtba Dam requires 69 km of road improvement and the construction of one stream crossing The stream crossing deoendino unnn it« could cause
TAMS-ULG B.r^Akflbo River B„|,
Development MAiUrPl.n
16
Chapter 2PRE FEASIBILITY STUDIES
VOLUME V
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
h« used for many years following dam construction, the major structures should be designed to
’ 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 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 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 m accordance
with the following principles
•   Limit   the   time   and   area   of   exposure   The   potential   for   erosion   is   greatly   reduced   if   the size  of  the  disturbed  area  is  small  or  its  duration  short  In  some  instances  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  pnnaple is  achieved by  using devices  that filter sediment from runoff or that detain runoff so that heavy  particles  will settle It includes  the use of materials such as silt fences, straw bales, brush barriers, and sediment traps and basins
•  Manage  only  the  sediment  and  runoff  from  the  site.  For  this  discussion  we  are  concerned only   with   Geba   Dam,   not   with   regional   management   of   runoff   and   sediment   Diversion berms and channels might be required to divert clean runoff around the site
Q^Lgntfappurrenani works.
ecause much of the required fill will come from the reservoir impoundment area, its impact upon ' e environment is encapsulated within that of the reservoir The demand for rockfill (nearly 
mem) require quarries outside the reservoir area. Quarry side slopes should be graded to a gen e gradient prior to their decommissioning, the quarry floor should be sloping towards the
TAMS-0LG^Iro-Akobo River Burn Integrated Development Muter PUn
Chapter 2PREFEASIBItm STUDIES
v OLU]\fE V
back  cut w that runoff and sediment arc  impounded Pnot to the rainy  season, the entrance should be partialis  cioscd with n berm in order 10 retain runoff Upon dcccmmis the quarry should be gradrd to dram in order to reduce the habiiat for mosquitoes
quarry
sorting
With  regard  to  dnetyron  wrrks,  spoil  from  tunnel  borings  should  be  removed  to  a  protected  sic isolated from streams, risers, and rhe reservoir
C'.W‘Xim<rj^>/prtyy'<- The study  by  ARDCO-GEOSERV (1995) shows  that 28 households  will be dislocated by  the Geba reservoir The World Bank  resettlement criteria for dislocated people should be followed The farmer gross  margins  for the reservoir area is  estimated to be 250 bin or USS per year If rdocation costs  are taken to be equivalent to 3 years' revenue plus  assets (estimated it USS 500). they  become USS 620 per household or USS 17.360 fOr the 28 households
The  reservoir  wiD  impound  90  km;   The  worth  of  its  standing  timber  as  dry  woody biomass  has  been  estimated  in  a  previous  paragraph  The  previous  assessment  shows  that  28 households  ask  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  Bin  per year  from  agriculture,  thus  the  total  worth  of  the  lost  agriculture  (less  assets)  is  7,000  Birr  per vear (USS 1.120 per year)
Lw  of  htstcri,;  cultural  or  aesthetic  failures  These  components  were  not  assessed  at  this  level 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 time It is a subject that will require attention during feasibility studies
Prohferaiton of (ujuaiic 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 io such an extent that they 
pose problems to the dam operations or fishery developments
DmnoraTion of *aier 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  and the residence time of the water in the reservoir From a totally  empirical assessment of the Geba Reservoir, it would seem that the short residence ume coupled to Lhe small reservoir area would place the reservoir out of lhe severe risk  category  For the purpoMt of this  prefeasibility  study, it is. however, recommended that the reservoir area be totally  cleared of all biodegradable biomass  In addition, a multilevel outlet should be considered to release water from different levels
Resenyir sedimentation The reservoir will likely  accumulate coarse sediments  at its  inlet and at principal inlets along its flanks Fine sediments may develop into density currents that will carry1 as  far as  the dam face, where they  will be flushed through the low level outlet. Sediment accumulation tn the reservoir is estimated to be 1,320,000 cubic metres per year Prior to design a sediment measurement campaign should be undertaken to confirm the estimate The reservoir dead storage is designed to accommodate a minimum of 50 years of sedimentation
TAMS-ULG Baro-Akobo Rhvtr Baiin Intefrated Development Matter Plan
18
Chapler 2E FF.A5T       STUDIES
BlLrn
VOLUME V
fisheries The reservoir may interrupt fish migranons,  u this has not been directly
bt
during the course of this or previous studies A fish ladder and hatchery should be
consider
re l(iteddisenses  At  this  level  of  prefeasibility  study  an  assessment  of  the  Geba  reservoir "~  h^ecard  to  water-related  diseases  is  speculative,  only  some  indications  can  be  drawn  from '^tside die project area and. indeed, from outside Ethiopia
The  risk  of  malaria  and  other  diseases  related  to  mosquitoes,  gnats,  midges,  and  other  insect
-  C  ers  that  breed  or  depend  upon  water  (yellow  fever,  dengue.  Onchocerciasis)  will  change  from 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. Anli- maianal 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 bnngs  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 ofBtomphalaria or Buhrrus
Infection  would  affect  people  who  used  the  reservoir  for  recreation  or  as  a  source  of  domestic water  The  greatest  risk  would  be  on  the  lee  shore  of  (he  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 io 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 ihe 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
Seikhozpromexport (1988) reported the absence of the mosquito earners of Leishmaniasis in the
owcr basin There is no information about their presence in the vicinity of Geba reservoir or,
n f ed. their continued absence in the lower basin The risk of helminthiasis from hydroelectric 
projects is low as this kind of project does not call for the same kind of intimate contact between
soil, and water as does irrigation
f°r   waler  Provisional  minimal  continuous  releases  from  the  Geba  Dam  and
studies114
d IVersions
.            are  computed  at  8  percent  of  mean  annual  discharge  or  0  70m’/s  Feasibility 
P°pulau^ te squired to evaluate the effectiveness  of this  discharge to sustain present 3 flow (jOn$ Water organjsms  and competing water users  The present study  has  not computed usually  curve based on mean daily discharge, from which minimal flow requirements are
——----------------------- ----------------- --------------------------- - "
ar ">Akobo Rjver Basin Integrated Development Mailer Plan
Chapter 2i
pREFLASLBILm STI DUS
The Ge-ba reservoir will require lhe relocation of 28 hoir
The GeOa reservoir mu i«|
U
..w ----- -------------------
WI
currently resident in its 90 km*' area The development is unlikely to attract an influx ° JS€fw< into the area other than for the dam construction
15 The Recommended Project
Z S. 1 Project Description
The Geba Project storage dam is located on the Geba River at the downstream end of a flood pUin. where substantial storage can be developed with a low dam At the site the drainaa area is 1.08b square kilometres Al full pool elevation 2170 the reservoir has a surface area of
1
about 66 km . « minimum pool elevation 2145 the surface area reduces to about 10 km
?
dam is 45 m high above the river bed with a crest elevation of 2175. It is of zoned earthfl]
construction.
The spillway  is  ungated, 80 metres  long, with a crest at elevation 2170 During passage of the PMF the maximum surcharge will be 2 metres  Downstream of the crest, the chute narrows  to 53 metres and terminates in a 25 by 53 by' 7 metre deep stilling basin The total length of chute and stilling basin is 450 metres
The  two  diversion  tunnels  are  4.2  m  in  diameter  and  500  metres  long.  The  diversion  dam  is  of 15 metres maximum height One of the tunnels will be converted to a low-level outlet for making power releases The control shaft could be constructed before diversion, but gate, hoist and 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 have gates at three levels for selective withdrawal purposes, and two sets of high-pressure slide gaies.  one  service,  the  other  emergency,  will  be  provided  just  downstream  of  the  selective withdrawal  shaft  The  sendee  gates  will  be  closed  during  operation  of  the  selective  withdrawal gates so the latter can always be operated umlcr balanced head A small stilling basin is provided at  the  downstream  end  of  this  tunnel  for  energy  dissipation  during  operation  at  high  reservoir levels
The first power diversion is located 4 kilometres downstream 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 built, equipped with 10-3x1.5 m sluice gates Downstream of the intake structure, the canal,
sized for 51.7 nr7s, the peak power flow will generally have a 12 metre bottom width fl
metre depth. It is expected that it will be mostly excavated in rock and will be concretc-tofi
3-metre wide access and maintenance roads will be provided on both banks The canal will have
a total length of 3500 metres When more is known about the topography and condition of the
rock, it may prove advantageous to size the canal for the mean daily power flow and provide 3
re-regular an g reservoir at the head of the penstock for daily pondage
The penstock is 3,2 metres in diameter and 700 metres long to develop a total head of275 metres The maximum plait thickness is 30 mm
TAMS-UW BuroAfcobfl Rher Basin faftgraud Development Mader Plin
20
Chapter 2PREFEASIBn.m STUDIES
VOLUME V
At the powerhouse the penstock will feed a manifold and supply four JHIW turbine-generators 
Ahemattvely’ft nn^lt ** preferable, with staged development, to construct one 2 25-m diameter
Estock to supply two 28-MW units, and build a second penstock at a later time Upstream of
Jhe turbine, each branch pipe will be provided with a 1 40 m diameter inlet valve to allow isolation
of individual units
Each 28 M^V generating set will consist of a Francis  turbine having a runner discharge diameter o f 1 |0 m and a 10-pole generator which will be rotating at 600 rpm. The powerhouse, which will consist of four generating bays and one service bay. will be 35 metres long by 12 metres wide, and the bottom of the draft tube will be located approximately  9 metres  below the normal minimum tailwater level Tailrace will be very short or non-existent
The four transformers  are anticipated to be located at the 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 lie), 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  rhe  first,  or  a  total  of  17  km  from the   dam   The   diversion   weir,   the   intake   and   the   canal   cross-section   would   all   be   similar   to diversion   no   1.   with   appropriate   modifications   due   to   differences   in   topography   and   geology. The power canal would be 6000 metres long leading to a penstock 3 2 metres in diameter and 400 metres   long   to   develop   a   total   head   of   175   metres   The   maximum   plate   thickness   for   this penstock  is  20  mm  At  the  powerhouse  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  I  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 
‘Ong Tor a total area of 135 metres by 100 metres This power plant is located only about V: km
om the Metu-Bedele road, near the village of Achibo
2 5 '2 Quantity and Cost Estimate
^outs, profiles  and sections  have been developed in suffident detail (see Drawings  GE-1 to GE-
such° Ot),a*n
appropriate to the prefeasibility level. In addition to major cost dements
fo    excavation,    concrete    and    earthfill,    quantities    have    been    computed    for    such    items    as rrnu° ^ reinforcing steel, drilling and grouting, rock anchors, gates and other items
r
deriv^?^5 U$Cd t0 deve,°P the detailed cost estimate are shown on Table 2.10 These were
South An?”1k'dS for a shnilar project subjected to international competitive bidding in Africa and erica and adjusted to a common January 1996 price level
Chapter 2
211
PREFEASIBLLITY STL dies
Table LIO Unit Prices (January 1996)
Item
Unit
Unit Price"^'"''
Common Excavation
m
3.62
Rock Exca\ibon
nV
9.0-1        ”
Portal Excavation
nr
6 78                         -
Tunnel Excavation
i
m
50.84 ”
Borrow Excavation - Common
m-
3,39
Borrow Excavation - Rock
m-*
4.80                             -
Mass Concrete
m;
9039
Structural Concrete
m3
129.94
Concrete Lnina (tunnel)
m1
203 38
Formwork
y
50 85
Steel Reinforcement
T
1,242.90
Unprocessed Fill (placement )
mr
2.26
Processed Fill (placement)
it?
6.78
Filters
m’
16.95
Drains. Transitions
m
11.30
Imperious Core
m
5 65
Drillina (confined space)
m
79.09
Drilling (open space)
m
56.50
Grout in e
T
564.96
Tunnel Support - Rock Bolts
T
6,779
Tunnel Support - Shotcrete
“T --- -------------------- m
28.25                , _ ___
Tunnel Support - Arches and Rjbs
T
2.260
A detailed cost estimate is presented in Appendix 2-1 and summarised in Table 2 11
TAMS-ULG Ba ro- A kobo River Basin Integrated Development Master Plan
22
Ch*P«r XPRE
Table 2-11 Geha Hydroelectric Project Cwt Estimate CUSS - January 1996)
'7C57& Appurtenant Works
FEASTBli m' STUPES
VOLUME V
psnri     jLt-i—— ------ Civil Works
35.430.000
Equipment         -------- ----------------------- --------
1.420.000
^^u,rrl’lani and Waterway. No. 1
~            Civil Works
15.320.000
Equipment
51.970 000
"^wer Plant and Waterway. No 2
Civil Works
19.850 G00
_    __   r r              —    5
Transmission Lines
JEauipment
36,000.000
31,500,000
Subtotal
191.480 000
Contingencies (20%)
33 300,000
Enn & Adm (10%)
22,980.000
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   214   years,   providing   that   large   scale   topographic   mapping   and geotechnical  exploration  could  be  made  promptly  available  Allowing  6  months  for  review  of  the bid  documents  by  the  Owner  and  the  lending  agencies,  and  for  the  bidding  process,  construction could  start  36  months  after  commencement  of  the  feasibility  study.  Depending  on  the  electric power  demand  at  the  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  3)4  years, if  only  because  of  lead  time  required  for  the  outlet  gates,  penstock  and  powerhouse  electro mechanical   equipment   Thus   it   may   be   envisioned   that   first   power   from   this   project   could   be available about 6 years after commencement of the feasibility studies.
Figure  2.4  shows  the  anticipated  construction  schedule,  assuming  that  the  power  Diversion  No - would be developed with one year lag
26
-  Economic Appraisal
o               ^'Vclroelet:tric Project will form part of the ICS and therefore should be evaluated as
d
emo  lda,e proJect in the generation expansion plan of the system. Essentially it should be
the nSUa,ed tflal ,he
j sierri.
inclusion of the Geba project represents the least cost expansion plan for
G Bart^Akobo River Basin Integrated Development Master Pbn
23
Chapter 2PREFEASIBILm STI DIES
v °lu.mEv
___
Ihr  in  the  power  sector»  tn  transition  from  the  consideration  of  large  pr0)<n
1       ' xlri’u and Chemoca-Ycdi. to medium-sized projects such as Gojeb and Tekeze
X«quo« thoe B "O ddwd las «* npuison plin of the system The new best opllon
the raw WBal “ 106«enmnr the long run marpnsl cost of energy and to use th„ fc
oLua-e benefits f« cantHae projects Studies tnlo tnterconnechons wtth neighbor*,
eountnes hoe used e »*e of VSS 0 06 per kWh is the long run marginal cost of energy 
silue wis used for the present assessment
As a check on the economic strength of Geba. companson was made with other projects under consjderatwn for the expansion of the ICS. using such parameters as the unit energy production cos: and the cost of installed capacity
As demonstrated in Section 2 3 5, the economic internal rate of return of the Geba project, using an enerp %alue 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 Instilled Capacity (USS per kW)
Geba 1 and II
1391
Gojeb
1740
Aleitu East I
2053
Aleltu West
2865
Halele-Werebesa
2400
Chemoea-Yeda I & FI
1816
It can be seen from the abo-.r that the Geba project compares very favourably with any alternative hydropower projects presently under consideration
Finally the low energy production cost for the Geba project, at about USS 0.038 per kWh, « significantly cheaper than any thermal plant option
TA.MS-ULG Baro-Akobo Rher Baiin Integrated Development Matter Plan
Chapter 2feasibility studies
PRE
VOLUME V
3.
gumero hydro electric project
Introduction
JJ.l Project Concept
The Master Planning studies  have identified a number of small hydroelectric  projects  in the Baro- Mcobo basin that would be suitable to meet the relatively  small regional demand for electric 
nover  The  most  promising  of  these  projects  is  the  Gumero  scheme,  located  on  the  upper  reaches of the Gumero River approximately 27 km west of Metu
The project consists  of a regulating reservoir downstream of a relatively  steep area in the upper catchment of the Gumero. and 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 three power diversions which can develop about 12 MW, 18 MW and 20 MW respectively
The project can be implemented for supply  of electricity  in the basin as  a staged development with each successive power plant coming on line at the time when 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
2.1.2    Project Area
The project area is  located on the Gumero River about 6 km upstream of its  junction with the Ofa and 32 km upstream of the latter’s  junction with the Birbir River The storage dam site is  27 km west of Metu and, at its  closest point, the Gore-Gambela road is  9 km south of the site. The dam site area is  forested, with moderate relief The reservoir area is  within the Gumero flood plain *ith numerous  houses  and considerable agricultural development on the hilltops  surrounding the ^sevoir. Land slopes  at the site are about 10% and the river gradient is  about 0 12%, At the
lv
eruon  sites,  all  on   the  Ofa  River,  the  cross  slopes  are  about  15  -  30%  and  the  river  gradient between  3  and  8%.  The  Gumero  River  rises  to  the  southeast  of  the  dam  site  al  about
gQQ31100     2000     thC     ®tc     the   river   is   al   elevation   1580,   falling   to   elevation   1340.   1120   and at powerhouses for Diversions I, 2 and 3 respectively.
J / J                        Planning
BOriCa f
’“WM*-4\T UOi 1UCI1LLLJCO lOUI
sunn jJHUlO ai               vaaAiaivra,  OHU
* Or a lotaJ installed capacity of 3 19 MW. There are also two hy droelectric projects in the
Integrated Dcvefepment
251
PREFEASIBlLin' STI DIES
_______________________________________________
baiin at Sor (5 MW) and near MizanTeferi (800 kW) Globally for the three regiOns
GWh  Projections  for  these  regions  average  grouih  rates  of  7.4/o  for  energy  sales  and  s peak  po*cr  demand  (Figure  3  I)  over  the  next  twenty  years  II  is  anticipated  that  the  peak  J* demand  in  2020  uSH  reach  61  MW.  In  that  context,  it  is  expected  that  a  project  such  as  (£‘; ^ith   the   potential   for   in   installed   capacity   of   approximately   50   MW   would   be   a   suitabje^ poim   project   for   the   rear   2020   horizon   Furthermore   the   Project,   by   its   nature,   a   ca^ three  hydrodectnc  installations,  is  well  set  to  be  staged  and  to  provide  peak  power  as  the  re?(> demand  grows  It  should  also  be  noted  that  EELPA  is  planning  connection  to  the  ICS  in  th^ future with two ties in the basin at Ghimbi and Sor scheduled for 1999 and 2000, respective
32 Basic Data
3.21 Topography
The only  topographic  mapping available is  from the Russian aerial photography  of 1984 Th scale of these maps  is  1:50,000 with a contour interval of 20 metres  and supplementary  cortom of 10 metres
3.2.2    Hydrology
The Gumero storage dam is on the Gumero River and it has a catchment area of 443 km1. The hydrometric  network  of the Baro River basin, which includes  the Gumero River, is  poor with i total of 10 stations  and only  two stations  having more than twelve years  of records. These an on the Baro River al Gambela and on the Sor River at Mttu where the catchment areas are 23,461 km: and 1,648 Jan1 respectively There is one gauging station on the Gumero upstream of theste
2
with a significantly small catchment area (106 km )
The  river  flow  at  the  location  of  the  dam  was  estimated  in  accordance  with  the  mcthodol0£!, 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 lb<5 catchment, and
stochastic modelling to generate long-term (41 years) monthly flow series. Table 3 1 shows the long-term monthly average at the dam site
Table 3,1 Average Monthly Flows al Gumero Dam (m /s)
J
January
1 46
July
February
17 50
1 00
August
20.96
March
0.63
April
September
23.77
0.76
October
May
18 77                   —-■
2.58
June
November
6.27                          '
___
7.67
December
2.54            '
TAMS-ULG B»ro-Akobo River Bulr, Integrated DM k>p
5 mftH Mailer PUB
26
"PEAK POWER DEMAND (MW)
Baro-Akebo Basin
Paak Power Demand Forecast
Figure 3-1rREFEASIBILin STl'DIES
The lonflem meen innual flow is S 66 m’.'s« or 273 mcm Approximately 91% of I|)al
(249 mcm) 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 p
f
er 0
determine flow for different return periods at the Gumero site The results of this *° (Annex IC), which arc shown on Table 3 2, were based on the Sor River gauging statj^ ^
Table 3*2 Flood Frequency Analysis al Gumero Dam
V °LlJMtv
1
Return Period
Discharge (m V*)
lOvear
182
lOOveir
313
“
500 vear
462
For the meteorological and rainfall gauging stations located in the vicinity of the basin, a statistical analv-sis  of the maximum daily  precipitation was  performed Applying the Hershfidd methodology. as  indicated in .Annex  IC - Flood Studies  of the Master Plan, the precipitation dau were usedTo 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 33 Probable Maximum Precipitation
SUtiODJ
24-Hour PMP (mm)
Gore
400
M«u
336
Hururnu
501
Based on this  analysis  the 24-hour point PMP for the Gumero catchment area was  estimated to be 400 nun. For the purpose of this prefeasibility study, a simplified HEC-1 model was developed to estimate the inflow hydrograph of the spillway  design flood The peak  discharge is  estimated to be 720 mvsec
There is no available data on suspended sediment in the vicinity of the site. For the purpose of planning the reservoir operation, studies considered the accumulation of sediment in the resen-oir
A discussion of the sedimentation estimate for all reviewed reserv oirs is presented in Annex IF to the Master Plan Report The annual rate of deposition in the Gumero reservoir was estimate to D« 674,000 m
3,2.3   Site Geology
"j'r 5 ° ^
n
fGOr» >
XiXal n^e LT
hOrnbIend'
^-sses On the l
^erSl Xn ±
h
P
ShC" gneisscs ™ 
e ?mCT0 35 km upstrcam of,hc>ctlon
iS On the £coi°g«^J Sketch map at 1 60,000 sc^
pho,os 1584 and 1585 Tte area has moderate relief and ‘
Uplands in the °™e dam site arC
in the area The site J
valley sides are foresrp/
and haveXded M
rounded slopes No large areas of rock are seen immediately near the dam site, but
L IX. B.roAkobo Rncr B»itn faffed Oevrkptnenl Muter Flu
27
Ch*p"r 3pREFZASlBlLm' STUDIES
VOLUME V
oximately 6 km north northwest of the dam she. at Guracna Mountain, basement gneisses 
distinct foliation striations outcrop and a rockfill quarry here would be easy to develop The
* 1 tie slopes outside the steep valley rim reputedly have suitable residual clay for impervious fill
^Basalts may also be available for a rockfill quarry No sand and gravel deposits occur in the area
A rockfill dam is recommended for this she A diversion tunnel should be easily constructed in
either basalts or gneisses with support of shotcrete, wire mesh and rockbolts
3J        Projecr Development
jj_1 Project Options
Based on aerial photographic  interpretation, a suitable quarry  could be developed at Guracha mountain, about six  kilometres  north of the site, which would require overhaul However, rock reportedly  also outcrops  on the right river bank  at 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 run-of-nver development at the Gumero 2 diversion she might be considered However, it does  not appear likely that the flow would be sufficient to justify the high cost of such a small project
It appears  possible that a project to irrigate the bottom lands  upstream of the proposed hydroelectric  storage dam site would be feasible, A site for storage for such a project has  been identified 15 km upstream of the hydro she. 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 quantity  and cost estimates  have been prepared accordingly. When more detailed, and larger scale, topography  becomes  available, it may  well be that a more economical site can be found, or in any event that a more realistic and economic layout and arrangement of structures can be made.
^■32 Reservoir Operation Studies
As indicated above, the reservoir will regulate the river flow to be used at three downstream
y roelectnc power plants The HEC-5 computer model was used to estimate the yield, or firm Ow, that can be guaranteed by operating the reservoir so as to release a constant flow. For the
purpose of this study, the yield was defined as the constant monthly discharge for which the long- ro^aVCT?SC defi6t *S 2% °fthc yidd <98% reliability) The HEC-5 model performs a monthly 
yield in °»/lie 4^’year ^ow time series at the dam site (Table 3.4) Figure 3 2 shows the
s m s of the Gumero river at the dam location as a function of the reservoir active storage nn-r .CUn? Was U5ed to estimate the yield of the reservoir for a set of maximum reservoir operating levels.
obo Rjver Buin Intefreted Dcvdoproent Muter PUn
Chapter 3TiWi 3-4
Monthly Row* it Gunwro Dam (m3/«ec)
Annual 9.05 744
1038 768 9.SS 867
001
1003 1144
043 1036
0 74' fl 91
1307 1211
979 1091
9 56 726 531 9.18 6.45 786 7.97 706 077 5.B6 7.94 642 703 6 18 I 554 7.36 S 17 7.85
11 30 7.72
10 5* 7.29 958
JD-QO l.flflFirm Flow (m3Zs)
Reservoir Active Storage (mcm)
Gumero River at Gumero Dam Site
Yield Curve at 98% Reliability
Figure 3.2PRE FEASIBILITY STUDIES
_____________________
The active storage of each reservoir determined as the storage above El ] gqq account the accumulation of 50 years of sediment The area-capacity curve of the ** reservoir was determined by the use of the methodology developed by Borland Moody Table 3.5 shows die firm flow at 98% reliability' for the three reservoirs i ** optimisation of the Gumero project Figure 3 3 shows the results of this com ut
P    at‘
reservoir with a maximum operating level at El 1,610.
IOn ^Or
3
Table 3.5 Gumero Reservoir Firm Flow (m /s)
Maiimum Reserv oir Level
Active Storage (mcm)
Firm Flow (  7 y *1
ms
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 u-n determined assuming an overall efficiency of 85%, and waterway head losses of 6% The grosj
developed  at  the  first,  second  and  third  power  diversions  are  120  metres,  180  metres  artf 205 metres respectively Table 3.6 shows the annual firm energy generated bv 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   Diversion No.2 Firm    Diversion No.3 Firm Energy (GWh/yr)        Energy (GWh/yr)        Enemy (GWh/yr)_
El 1 605
53.6
80.4
91.6
El 1.610
64,3
96 5
109.9
El 1.615
67.6                                   101.4
115.5
3-3.3 Access and Transmission Lines
As previously noted, the mam Gumero storage dam is about 9 km from the Gore-Gambela road in country  with moderale relief An all-new road along such an alignment from this  road would appear to be the best choice for access  to the site An alternative would be to improve the easting Metu-Burusa road and build a new' road about 4 km long from the Burusa road to the
am site The former alternative has been chosen for the prefeasibility study.
i       * appear 10 be an existing access anywhere near the three diversion sites It will
The reno
probably be necessary', therefore, io construct an access road through difficult terrain and the right bank oi the nver, where all three diversions are located From the dam to Diversion is .km as ihe crow flies, 4 5 km further to Diversion 2. and an additional 15 km from Divers'0" 2 to Diversion j
Since the Gumero project is proposed primanly to generate electricity for use within the basin, the transmission line should connect directly to the existing Sor-Metu-Gore-Gam kV line, 9 km from the site However, at full development (all 3 diversions), the transmission line length would be al least 37 km
TAMS-ULG Baro-Akobo River Buin Integrated Development Muter Plan
Cb>prfr JArea in km2
Reservoir Capacity (mcm)
Leaend
Inrtal
Alter SetJmenoton
Gumero Reservoir Area-Capacity Curve
Figure 3*3PREFEASIBILITY studies
v
3.3.4    Project Layout
Based on the small-scale (1:50,000) topography, the dank spillway and outlet works arr^£e appears to be the most favourable. The dam is at the downstream end of a marshy, al^-^
1-2 km wide plain where a substantial amount of storage can be developed with a low <33
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 (> .. right bank, a spillway crest and chute structure would appear to require less excavation but coJj present a hazard to the embankment dam, since rock is probably lower there than on the left ti diversion tunnel also would appear to be shorter, but the lesser overburden could produce tunnelling problems
On the other hand, on the left bank there 1$ a high knob. 15 metres above dam crest, that couki separate the spillway crest structure from the dam abutment, and might also be indicative harder rock for tunnelling. Consequently, in the absence of larger scale topography or ar. 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 maps Judging from contours on these maps, the locations appear reasonable, and likely canal rouics,
all located on the right bank of the Ofa River, appear feasible at the mapping scale available
.Alternatives will only be able to be studied when larger scale topography, and field geotechnical reconnaissance, becomes possible
3.3.5    Project Selection and Optimisation
33
For the purpose of selecting the size of the project to be developed at the Gumero site, cost estimates  for three levels  of reservoir were prepared The project-installed capacity  has  bee selected to provide a project plant factor of approximately  60%. As  a consequence, for each reservotr level selected the installed capacity is determined by the firm yield of the reservoir at du: level
Since the hydroelectric  benefits  of the project do not depend on the head created by  the stores* dam. the minimum reservoir operating level is  selected as  the minimum technical aft- environmentally  feasible, taking into account the estimated sediment deposit in the reservoir o^er the life of the project On that basis  the minimum reservoir level selected is  at El. 1e 3.7 shows the mam characteristics of the projects selected for optimisation.
TAMS-ULG B*m-Akobo Rher'Buin integrated Development Matter Phu
31
Ch*Pter3PREFEASEBILITY STirDres
VOLUME V
$^jrnum Reservoir Level______________
KfatimumReservoir Level
7
Table 3-  Project Optimisation Reservoi1r. an 600d Power PlanI t6 C00haracteristics
1 605
1   6I0_
1 600
1.615
Averaue Regulated Discharge (m '/sj
' 6_5
____7J
_
82
Max Power Discharge (m7s)__________
__ 108
13 0
112
Diversion No 1 Head (m)____________
Diversion No 1 Capacity (MW)
Diversion No 2 Head (mi_________
J20_
10.2
180
_120_
12.2
180^
Diversion   No   2   Capacity   (MW)
15 3
18 4
120
12,9
Jl80
19,3
Diversion No 3 Head (m)
200
200 200
Diversion No. 3 Capacity cMW>
174
21.0
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 ihe 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 (TRR)
taking into account the feasibility study, design and administration costs, the cost of construction
allocated over a period of four years, the cost of operation and maintenance and the revenue from
the sales 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 cquipmen 1 0% for transmission lines.
Revenues from the sales of firm energy were estimate tW)
■ ot thP rate of USS 0.07(kWh (January 
a
For purpose of this analysis the three power plants were built to m
of   the   Haro   Basin   The   first   power   station   would   come   on   line   in   . foe third in 2019
second in 2011 and
---------- —__________________________________ % er Basin Integrated Development Master Plan
32
Chapter 3Table 3 8
Project Optimization - Cost Estimate (USS '000) PriwLuvd January 1996
uam a Preliminary
-----------------
t ,729
2,124
2 557
Man Dam
6448
11 oei
13 963
Access Road
400
400
400
iDtversion Tunnel
1 920
1 920
1 920
Spilhwoy
545
545
545
Low Level Outlet                                                     216              216
216
subtotal 13,259
power Plant & Conveyance
[Nvercton No. 1
4C
16.287 19.601
subtotal t,»2»
Diversion No. 2
n.113               11427
Preiimnary
1.650
1.664
1,926
Access Road
936
936
936
Power Intake
0
0
0
Power Canal
1.425
1.425
1.425
Power Tunnel
0
0
0
Serge Shaft
0
0
b
Pressure Shaft
0
0
0
Penstock & Manifold
1 600
1.600
1,600
Powerhouse & Equipment
7 038
8464
66781
Subtotal 12,642
Diversion No. J
14.288             14.765
Prekminary
2.691
' 2.970
3,103
Access Road
1,599
1*599
1 509
Power Intake
0
0
0
Power Canal
6.600
69D0
7 300
Power Tunnel
0
0
0
Surge Shaft
0
0
0
preesi^e Shah
0
0
0
Penstock ft Manlfcdd
2.000
2.000
2.000 ,
Powerhouse 6 E augment
7 743
9.301
9 790 ;
Subtotal         20,633          22,770             23,792
Trant mission System
Prewninary
fil3
824 ,
saF
s\wrtchy>fd D*v Hal
550
550
550
Syrftchyard Ov No2
Switchyard Drv Nq3
550
580
5S1
568
611
625
Tranerreaekn Line
3.750
3750
3750
Subtotal 6,231
6.315              6.343
Rewrvoir Area Clearing
649
7M
1,4*1
Population ftekKatfcm
700
700
7O0
Subtotal
72,22^
------TaTTF
Phyticat Contingencies (29%J
12.790
14.446
15.643
Engineering ft Ad rd r I > Era ton (10%)
7.574
6,560
9.386
I
Total Direct Cost! 84,413 | 95,343 | 103,246 |PREFEASIBILITY studies
VOLUME V
Based on lhesC assuniptions the °f the ***** Table 3 9
schemes were computed as shown on
Table 3.9 Project Optimisation - Internal Rate of Return
-
| Wx- mum Reservoir Level
' DiversionJ^cr 1 Inst Cap__________ Diversion No 2 Inst. Cap _________ Diversion No 3 Inst. Cap
Total  Construction  Cost  (USS  mil  ) Annual 0 & M Cost < USS mil i
Firm Energy' ( GWH vr) ________ Annual Revenue (L'S$ mil»
IRRi%i___________'                 27
1605
10.2
15 3
17.4
I
1610 12 2 184
21.0
1615 12.9 m
22.0
84.4
95 3
103.2
1 06
1.24
1.31
225
271
285
15.78                         18.95                       19 94
11 0%                       11 4%                      110%
On that basis, the Gumero project with a maximum operating pool at El 1,610 was  selected The
installed capacity  of each of the power plants  was  selected to meet the 60% plant factor criteria
Each power plant will be equipped with two units  The total installed capacity  of the oroiect at
full development will be 51.6 MW.
14 Environmental Assessment
P ’ P J at
The Gumero Dam will impound the Gumero River about 35 km upstream of its  confluence with the Birbir River. Lis  site lies  in the upland portion of the Dlubabor Region The crest length of the dam is  700 m, its  maximum height 35 m and its  construction rockfill The reservoir would inundate 30,9 km2 to contain 300 million cubic  metres  (mcm) of water Its  normal minimum operating level is at El 1.600 and its maximum level is at El 1,610 m elevation The mean annual flow of the Gumero River at this  location is  estimated to be 8 7m 7s. Discharge from the dam would be diverted to generate electricity  at 3 hydro power installations, each of which is  serviced by a separate, in-line diversion of the Gumero River
Posirive impacts
The subsequent section discusses the potential non-hydroelectric benefits ofhydropo
Uood    control    The    flood    surcharge    volume    of    the    reservoir    is    ^00    mcm    in
i
rescrvo r
dorage of 160 mcm Flood attenuation will undoubtedly occur as ar 0
Wanons However, flood control is not the pnmmy ^ose of the
of the 1 ■50,000 scale map, it appears there is practically no settlement on the Gumero and 1 * rivers downstream of the dam site
Neither the study by Selkhozpromexpon nor ARDC
^ nn HWmnZ'ed
n
CStimatcs for impoundments in the upper basin Selkhozprom . p
lhal Abobo reservoir in the lower basin could produce an annual catch of 100 t
--------- ---
.____________________________ ____________
Rher BasLii Integrated Development Muter Plan
34
Chapter JPREFEASIBILITY STUDIES
2 210 hectares reservoir. This result cannot be extrapolated to upland re$ervoirs
without further study
Fuelwood Among the mitigations recommended by this assessment is the total clearan biodegradable material from the reservoir area The woody biomass of the dam and resetv^*
VOL^V
has not been surveyed other than in the context of the 1995 Woody Biomass Survey by Ihen?^ Using his results, the reservoir lies in an area whose potential dry woody biomass lies betj/
30 and 50 t/ha For the area of the reservoir (30.9 km ), this translates into a potential fbclwt
!
supply of between 92,700 and 154,500 tonnes At 5 Birr per 20 kg bundle of fuelwood. its
resale value, exclusive of the cost of collection and preparation, is between 23 and 39 million E-
(USS 3 7 and 6.1 million).
Recession   ayncullure   and   grains   The   reservoir   offers   the   potential   for   recession   grazing 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 doesm 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 are thus  have the potential for significant impacts  The area of influence of a dam project extendi from the upper limits  of the catchment to far downstream While there are direct environment! impacts  associated with the construction of the dam, the greatest impacts  resull from ’±e 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 Li 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, ar 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, Rivenne fisheries. Water-related diseases,
TAMS-CLG Baro-Akobo Rh er Buin Integrated Development Muter Plan
35
Cbap**r JpKEFEASIBlLm STUDIES
VOLUME V
- Conflicting demands for water, and
■ Increased land pressure
Construction camps usually comprise quarters for between 2nn a H^^wers. cooking facilH.es, toilets, generators, fuel dumDS
„ everything needed by a small town Their design is usuX’tem mac^nes' P^ng
600 meR
uafel life often extends beyond the penod required Mlelv fw
constnta™  7?he
0
"’'ir
of land clearing for the camp is likely to be insignificant To the maximum extent
The amount o
| eft standing to provide comfort for the workers as well as supply a seed
possible.              ^nip js decommissioned If people are to be resettled to provide space for the source ortC^9et^eiTien( policy currently followed by The World Bank should be followed
The amount of natural timber harvested for camp construction u
no precautions are taken Ideally , such timber should come fr E m°derate,y significant if impoundment Outside that area, its impacts are identical to those nf t™ • °f rescrvoir
native vegetation and disturbance to soil and water To th
should make use of such aerials as plarts aad metal sheZgXSad ££ P">J“'
,0 Sg”1g destruction of
The camp electrical powerhouse will create insignificant impacts  io 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 Lhe coinmencement of construction
Solid  waste  should  be  inanerated  at  a  location  removed  from  the  camp  and  neartty  tou^olds The design of sew age facilities should bear in mind whether or not e camp
used  after  its  decommissioning.  If  it  is  to  continue  in  use.  then  primary  sewage
required, otherwise, extensive septic systems might be permissible.
rv.                    m km of road improvement. Roads have Hoods The construction of the Gumer o Dam requires                  - manly because they' concentrate and been  shown  to  be  an  important  contributor  to  soil  er°sl0n-P",  ,  ¥or   subsurface  flow
distribute runoff as channel flow rather than as uniform
Access roads will be constructed to a high physical standard ^comp .
‘d
t0
^ardness)   in   order   to   accommodate   the   weight   of   heavy   equipment   hould     designed   to
e f^ed for many years following dam construction, the major stru “Wy the 25-year flood J *, Me t0 safely pass lhe '^^ue foS
Temporary
4
shoufo be constructed to a permanent standard if their use will contmue following
^Pletion of the dam or other structure
^ause road  ar
s      ex Ploiiation 1q ^^ve means of access to inaccessible areas, they open areas to increased 88m& farming, hunting High standard roadways should avoid intercepting
T A Hs rrT^~^—___  ________________ ______________________ __
River Basin Integrated Develop meat Matter Plan
Chapter 3PREFEASIBILm' STUDIES
primitive areas, national parks, controlled hunting areas and locations of exception
cultural significance unless the means to control trespassing to these areas are avaiiable°%
The mitigations of the potentially negative impacts of roadways rest with competent eng^
design Longitudinal drainage is likely to require a raised bed and ditches Cross drama^
follow existing channels and be designed to accommodate debris as well as water and
Culvert outflows should be constructed to a level below the stream bottom so as not t0
with the passage of aquatic life Culverts on steep slopes may require an energy dissipator bef*
they discharge onto unprotected land A Soil Erosion Control Plan should be developed <ju *
the project design and precede the onset of construction Its purpose is to provide guidelines ? controlling soil erosion, sedimentation and pollution.
The Soil Erosion Control Plan describes the location and type of controls to be implemented • clearly  identifies  special resources, such as  wetlands  and primal forests, that require proteaio:
Perceived  problems,  such  as  highly  erodible  soils  and  unstable  slopes,  are  clearly  marked  Ttt plan should contain basic drainage information, such as stream patterns, watershed areas, and :at size  and  location  of  hydraulic  structures  The  erosion  control  measures  should  be  in  accordr« with the following principles:
Limit the time and area of exposure The potential for erosion is  greatly  reduced if tie size of the disturbed area is small or its duration short In some instances stabilization cc 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  that  filter  sedunen from runoff or that detain runoff so that heavy particles will settle. It includes the use of materials such as silt fences, straw bales, brush barriers, and sediment traps and basin*
Manage only the sediment and runoff from the site. For this discussion we are concent only with Gumero Dam, not with regional management of runoff and sediment Diversity berms and channels might be required to divert clean runoff around the site
Dam and appurtenant works.
Because much of the required fill will come from the reservoir impoundment area, its impact
the environment is encapsulated within that of the reservoir The demand for rockfill (ncar^
0 5 MCM i require quarries outside the reservoir area Quarry side slopes should be graded to* gentle gradient prior to their decommissioning, the quarry floor should be sloping towards t
back cut so that runoff and sediment are impounded Prior to the rainy season, the q ■
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 • isolated from streams, rivers, and the reservoir.
Dislocation  of  people  The  study  by  ARDCO-GEOSER  V  (1995)  shows  that  7  households be dislocated by the Gumero reservoir The World Bank resettlement criteria for disloc3
TA.MS-ULC Baro-Akobo River Barin Integrated Development Muter Plan
Cb»PurVOLUME V
people sho
id   be   fbllowed    Ttie    famicr    gr0S5    ^S115    for   the   reservoir   area   is   estimated   to   be   250
year jp re|0cation costs are taken to be equivalent to 3 years' revenue plus
Birr. of L „,ated at U$s  500)’ they  become uss  620 per household or USS 4 340 for the 7
10
^ets (est'J™ *
household
al   The   reservoir   will   impound   j0.9   km   The   worth   of   its   standing   timber   as   dry has  been  estimated  in  a  previous  paragraph.  The  previous  assessment  shows  that
w ood>   ’®]js     being   relocated   It   is   estimated   that   upland   households   cultivate   about   0,5   ha 7   h0USp  °h  household,  on  average,  aggregates  an  estimated  gross  margin  of  about  250  Bin  per ^^fro^agnculture,  thus  the  total  worth  of  the  lost  agnculture  (less  assets)  is  1750  Birr  per  year ^55 280 per year).
f  historic  cultural  or  aesthetic  features.  These  components  were  not  assessed  at  this  level ^^FuT^main for feasibility investigations
of^ildlif^hghiiat   The   Gumero   reservoir   will   occupy   less   than   5   percent   of   Sele   Mesengo pFFrtedArea  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 Hooded 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 lime 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
lodegradable  biomass  In  addition,  a  multilevel  outlet  should  be  considered  to  release  water  from different levels
reservoir  will  likely  accumulate  coarse  sediments  at  its  inlet  and
as 
31008 ’tS
accumuiati    *    ^ace'
w  ere
Fine sediments may develop into density currents that will cany
^ (hev  will be Hushed through the low level outlet Sediment
a   sedimen   *"   reserv°’ ’
r s     estimated   to   be   516,000   cubic   metres   per   year   Prior   to   design
,ivestorag
COtMered
measu emcni
[          campaign   should   be   undertaken   to   confirm   the   estimate   The   reservoir e l » designed to accommodate a minimum of 50 years of sedimentation
1  he  reservoir  may  interrupt  6sh  migrations,  but  this  has  not  been  directly course of this or previous studies A fish ladder and hatchery should be
—- .
Akofao River Buin Integrated Development Mailer Plan
38
Chapter 3PREFEASIBILITY STUDIES
—- --------—- -------- ------- vo'-%
Water-related diseases At this level of prefeasibility study an assessment of thc " reservoir with regardto water-related diseases is speculative, only some indications can from outside the project area and, indeed, from outside Ethiopia
4 diseases related to mosquitoes, gnats, midges, and other mSfe.
>
The risk of malana and o
earners that breed or depend p
from being ^J^Xoir
habitat offered by the resen
these diseases can be reduced by^^^g
(yellow fever dengue, Onchocerciasis...) will ch£
The increase will result from improved bree^ shoreline vegetation Some of the nsks associate^
weliand vegetation, possibly by recession gr^
Qf
£
and are not
.Anti-malarial programs using such as D J*
•es;s"X... -—
r ^on™' f Wc onl for short-term. non-immune visitors to the project t*
the risk
Schistosomiasis does not present the same risk for hydroelectric reservoirs as it does for imgancr, which brings  man into intimate contact with water At Gumero. the potential for infection ij unknown given that we have no information about the presence of Biomphalaria or Buhmis Infection would affect people who used the reservoir for recreation or as a source of domestic water The greatest nsk would be on the lee shore of the reservoir, especially if vegetation wet 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 wue 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 informatiK about this disease is fragmentary and inconsistent Sclkhozpromexport (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 proximity to the site
S clkhozpromexpon (1988) reported the absence of the mosquito earners of Leishmaniasis in lower basin. There is no information about their presence in the vicinity of Gumero reservoir a. indeed, they continued absence in the lower basin The risk of helminthiasis from hydroelectr< 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
Z ,rhlme diversions are computed at 8 Continuous ^leases from the Gumero
’
stu<  e
^ ® will be required to evaluate
° f mtAn discharge or 0.70 m3/*
provid^ "
0 5     U2!er     organisrns     and   competinc   ®CCveness     ofthis   discharge   to   sustain   preseni
frn   w   su®c’em     data   to   compute   a   fl   S     J**   Cf    USers     Present   study   has   nor   beefl
from which minimal flow requirements scheme e„.,«ns
ratl°" CUrVe based on mean daily discharKc
us uaJly estimated.
"" dam ““ ^nhesr power sralron »
S km do»msr,eam of rhe dam, rhe second 12 km.
1 AMS-VLG Baro-Akobo Rher Bajio Integrated Development Master Plan
39
Cb»Pter5rRE
^HY ™^
S
VOLUME V
Each diversion takes water from the Gumero River to feed into a power canal The third 25              ^ave respective lengths of 3. 2.5 and 6 km The maps of these diversions and ^ ,cd                        nd)nk canals show no dwellings or roads in their vicinity We conclude, therefore,
their correspo that the nsk°
, s |ow, subject to the findings of the feasibility study
The Gumero reservoir will require the relocation of 7 households in its 30.9 km basin The development is unlikely to attract an influx of people
currently r«ia
into the area otneru
for the jam construction
yhe Recommended Project
3.5
j 5.1 Project Description
y Gumero Project storage dam is located at the downstream end of a marshy area, up to 2 km je and nearly 20 km long, where substantial storage can be developed without disturbance to
the exjstina agricultural development on the hill tops above the potential high pool level At the
2
site the drainage area is 443 km At high pool, elevation 1610,
the reservoir has a surface area
of 37 km2 and at minimum pool, elevation 1600, the water 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 PVfF 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 tunnel 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 *i1l 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 prodded just downstream of the selective withdrawal shaft The gates  will be open during t ^erS,'°n For Power operation, the service gates  will be closed when changing the opening of 1 untwMC1'Ve withdrawal gates so the latter can always be operated under balanced pressure. The baa ^barges  into the spillway  outlet channel excavated in rock  at this  point, so that a stilling
as(T"s not expected to be required
dlVei3ion   15   located  9  kilometres  downstream  of  the  dam  The  diversion  weir  is be built « C°ncrete  °8ee section, 12 metres long. On the right bank a canal intake structure will
for 1 j
2-2x3 m sluice S4tes Downstream of lhe intake stricture, the canal, sized
depth it j! 'the peak P°wer flow, will general have a 7 metre bottom width and a 2 metre ^de access^ttCd that il wiU mostJv excavated in rock  and will be concrete-lined. 3-metre ’^gth of 2600 maintenan<* 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
__ ___ ____ __________ ■
^Akobo River Balin Initialed Dcveiopment Master Pl-n
40
Chapter 3PREFEASIBILITY STUDIES
may  prove  advantageous  to  size  the  canal  for  the  mean daily power flow and p regulating reservoir at the head of the penstock.
V °Lt!Mlv
rovld
e a re.
The penstock is 2 0 metres in diameter and 400 metres long to develop a total head of 120 The maximum plate thickness is 13 mm At the powerhouse the penstock will bifurcate to & ?
2-6.1 MW turbine-generators, each turbine will be equipped with one 1 00-metre diameter valve, and will have a runner discharge diameter of 0 82 metre The turbine-generator sets' r run al a rotational speed of 750 rpm.
1
The powerhouse will include two generating bays and a service bay and will be 18 metres ]0 and 9 metres wide, and the bottom of the draft tube will be approximately 6 metres below th 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 long for a total area of 72 meires by 75 metres One line will be connected to the upgraded Gore-Gambela transmission line and the other will be connected to Gumero 2 switchyard The existing 66 kV line will be sufficient to cany the load from Gumero to Gambela when only Diversion No 1 is operating As the other plants,  Gumero  2  and  3,  come  on  line,  the  existing  transmission  will  require  upgrade  0: replacement to carry the load in excess of 50 MW. For that purpose the connection betwee power plants is planned 10 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 to develop a total head of 180 metres The maximuni plate thickness for this penstock is 15 nun.
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 , IS metres by 9 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 rhe
switchyard will have an overall dimension of 72 metres by 75 metres One bay will conned the power piani to Gumero I and the other to Gumero 3.
The third power diversion is located 15 km downstream of the second, or a total of about 30 km from the dam The diversion weir, the intake and the canal cross-section would all be similar t° 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 4 metres long to develop a total head of 205 metres. The maximum plate thickness for th15 penstock is 16 mm At the powerhouse the penstock will bifurcate to serve 2 - 10 5 unlis
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 valve metre in diameter, and a runner having a 0.75 metre discharge diameter The unit is at a spee
TAMS-UlJG Barft-.Akobo River Batiis Integrated OevelopiDCint Mister Plan
41VOLUME V
n mm The switchyard will consist of 5 bays (2 units. I line, 1 local ioad
of 60 metres by 75 metres The project be colwned
Gumero 2-
„ entity                    CO^ Estim^
nrofiles sections haVe bee" deve‘Oped in sufficient detail Drawings GU-1 to
U! Tn to obtain quantities appropriate to the prefeasibility level In addition to major cost
such as excavation, concrete and earthfill, quantities have been computed for such items e,<rn XrL reinforcing steel, drilling and grouting, rock anchors, gates and other items 
a.s term
rices used to develop the detailed cost estimate are shown on Table 3 10. These were LDI' L from bids for a similar project subjected to international competitive bidding in Africa and
America and adjusted to a common January 1996 price level Table 5.10 Unit Prices (January J 996)
Unit
Unit Price
Common Excavation
m3
3.62
Rock Excavation
m*'
9 04
Portal Excavation
m‘
6,78
Tunnel Excavation
mJ
50 84
Borrow Excavation - Common
m’
3,39
Borrow Excavation - Rock
nf
4.80
Mass Concrete
m3
90.39
Structural Concrete
mJ
129.94
Concrete lining ( tunnel'
nr
203.38
Formwork
m‘
50 85
Steel Reinforcement
T
1.242.90
Xwfcessed Fill (placement)
m3
2.26
Processed Fill (placement)
3 m
6.78
■jjhers
nf
16.95
, Crains, Transitions
n?
11.30
-jffPg^ous Core
nf
5 65
^nglconSned )
space
m
79 09
space)
jjHxning
-------------------------------------------------- -
m
56.50
T
564 96
ockBolts
T
6.779
T^V^J-SMcrete
^
----- T m
28.25
HE2IL. Arches and Ribs
T
2.260
ed cost estimate is presented in Appendix 3-1 and summarised in Table 3
-------- ------------------------------------------ -------------------------------- ------ Akobo River               Integrated DeveJopment
42
ChipterJPREFEASIBIUTY STL'DEES
Table 3.11         Gumero Hydroelectric Project Cost Estimate (L'SS - January
Dam & 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
i 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
Eng. & Adm (10%)
9.070.000
Total Construction Cost
99,780,000
J. 5.3 implementation Schedule
It is anticipated that feasibility studies and preparation of bid documents for the Gumero Project would require about 30 months, providing large-scale topographic  mapping and geotechnical exploration could be made promptly  available Allowing 6 months  for review' of the bid documents by the Client and the lending agencies and the bidding process, the construction could start 3 years after commencement of the feasibility' study At the same time a decision would be made on phasing of the construction Depending on electric power demand at the time, ard availability of transmission facilities, it might be decided to build the Gumero storage project, but only  the first Gumero diversion initially, with a consequent reduction in the initial capital
requirements. In any event, it should be anticipated that the construction of the road), spillway and outlet works, along with the power diversion, canal powerhouse would require 2!4 to 3 years, if only because of lead time requir<
dam (and acc»> 4 penstock 
for the outlet
gates, penstock and powerhouse electro-mechanical equipment Thus it may be envisioned first power from this project could be available about 6 years after commencement oft c feasibility studies, or about January’ 2005 assuming start of feasibility studies in January 1
Figure 3 4 shows the anticipated construction schedule assuming the project is implemented^ a continuous operation, i.e., that the full capacity' of the scheme is developed at once For 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, i the regional power demand With the first power plant commissioned in 2005, the secon w<
Chapter 3
TAMS-ITLG Baro-Akobo River Batin Inlrpratcd Development Mmtrr Plan
43^s®^SWDrcs
' o^riWE v
cMtM line'Holland rhe third in 20)9 Figu,.,, ,
a*’?’"" demand. 
, EtOn«»>icA'’',r‘iS”1
5 shows W
ThcOuniero P[® ^n3tnlCtion of isolated diesel generators
J
.  ^sji
be  supplying  electric  power  within  the  Baro-Akobo  basin  and  will  be  an
j|ternalive t0 ’
f this prefeasibility study, the recommended project has been evaluated in terms for the PufP°®e  °nerate<j firm energy It is estimated that small diesel plants generate energy at o f unit cost 0                    kWh Based on the discounted costs of construction and operation and
B of L,SS he Cj?,.llCTo project will generate energy at a cost of USS 0 049 per kWh
.  analysis  of  the  project  was  also  performed  taking  into  account  the  construction A  presen'  *  “.Qn   anj  maintenance  costs  For  the  scenario  where  the  three  diversions  are costs  and  ®PC    sarne   tjme   as   Ljie    dam  over  a  five-year  construction  period,  the  economic ^muTra'ie of return (EIRR) is 14 3%. When the construction of Diversion 2 is delayed and not
(^Omilissi  1%oned until 2012 and similarly Diversion 3 is delayed to year 2018. the EIRR is lowered
44
OapterJFIGURE 3.4
GUMERO HYOROELECTRIC PROJECT CONSTRUCTION SCHEDULE
-gy90
2010
zuia
Year
Gumero Hydroelectric Project
Implementation to Meet the Local Demand
Figure 3.5PREFEASIBILTD STUDIES
4. ITANG IRRIGATION PROJECT
4.1 Introduction
4.1.1 Project Area
The kang irrigation Project, called Itang-Lare in the Russian Master Plan, is located some 3C fan 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*5 7’E - 34°2]'Ey.c 8°09'N-8°27’N The area is  north of the Gambela National Park  Administratively, the projec area is in the Gambela region, Itang and Jikawo wcredas The project location is shown cn Drawing No IT-1
The project area is a flat plain, Its average slope is about 0 0005. Most of the area is covered by open woodland, grassland, including mostly bushes and shrubs The area is limited by the Bare River to the south, some hilly areas with elevation of up to 500 m to the north, the Jikawo River to the north, flat flood prone areas to the west and mild sloping terrain with some localised rod outcrops with peaks exceeding 500 m elevation to the east The lower (southern) part of the aiu along the Baro River banks is subject to flooding Flood water levels elevations along the Br: 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 to 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 2300 Population on the Itang and Jikawo wcredas and on the Gambela wereda are estimated at 22,05 43,685 and 30,115, respectively Population growth in the area from 1984 to 1993 is estimated to have been over 7% per year Most of the population is rural
Electric power is mostly lacking Itang is served by a small mobile diesel plant The nearc?1
power transmission line is the 66 kV Sor-Gambeia-Dembidolo line served by the 5 MU hydropower plant EELPA is studying the possibility of linking this line to its interconnect
system
Potable  water  supply  and  sanitation  are  practically  non-existent  The  Gambela  Regional Government is presently building a groundwater based (deep well) water supply project at n -
Small scale flood recession agriculture is practised along the banks of the Baro River in vicinity of the project area In the region at large, livestock is a major economic activity dry fanning is also present upstream in Gambela
TAMS-Ul.G Baro-Akobo River Basin integrated Development Master Plass
4VOLUME V
4.1- * Water Resources is the national
f
institution responsible for large scale irrigation
, nuntrywide water policy, development and management The Ministry of 'X* responsibility for a ncdtu e
er
. and local levels, the regional and local bureaux bear responsibility for day-to-day the                implementation of water and agriculture policies, development and services
«rnirct development, such as on the ongoing Alwero irrigation project, is the
ad hoe pro.ee. office.
Akobo   Master    ^'an    analysed   the   present   institutional   setting   and   made   several fl®  Baw'for  development  of  the  Baro-Akobo  River  Basin  One  of  them  is  the  creation  of P*0?0 B sin authority Details on the analysis made and the proposed measures are given in the iStfPlan report and in its Institutional Support Annex 3G
( j. Buie Data
4.21 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: Itang, Lare, Jikawo, Birhane Selam and Shenkwar Mountain for the irrigable area and Itang and Sefera Tabiya for the Itang reserv oir 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 rn contours and interpolations every 0.5 m This map was prepared by SelkhozprQmexpon in 1988-89
topographic map of the Itang dam area of 1/10,000 scale with contours every 2 5 m and ^terpolations every 1.25 m The available map is a reduction at 1/5,000 scale and covers bv??!?”™1* surface area of 5 5 km x 2 -1 km or 13.75 sq km. This map was prepared
^Ikhozpromexport in 1988-89
2 Climatic Data
^tic data <s -i
J 4^. eva avajlable for rainfall, temperature, wand velocities, relative humidity, hours of s Sp‘ration “d evaporation The source of this data is the National
3Qni« extent ,WV,Ces Agency (NMSA). Data was obtained through the previous studies and ’ lrect,y from the NMSA
^Akobo
----- —_____ -________________
er Baijf] Integrated Development MatCerPLaJi
Chapter 4PREFEASnHLITY STUDIES
Climatic Classi fication
The project area, according to the climatic zones of Ethiopia classification by the v Meteorological Services Agency, is located in the Tropical Climate n (AW) climatic zo
zone is defined as an area with a mean annual rainfall between 680 mm and 2000 temperature of the coldest month is greater than 18* C
Existing Climatic Stations
The only climatic station in the project area is located at Itang Stations in the vicinity f project area, in the Gambela Plain, include Pokwo. Jikawo and Gambela, all located within ak? 30 km distance Elevations at these 4 stations, in metres above sea level, are 415, 425 4]q 440. respectively Abobo, located about 70 km south of the project area is at elevation 455 Rainfall
Hi-
Monthly rainfall records in and near the project area, dunng the period of 1952 through 1992, rj as follows;
Itang 114 months from 1973 to 1982 and 6 months in 1985, or a total of 120 months 
Pokwo 15 months from 1956 to 1957, 10 months in 1959, 94 months between 1961 and 196'
55 months between 1975 and 1980 and 41 months between 1983 and 1987, or a total of2]5 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, are given in Table 4 1, below Table 4.1 Long-term Rainfall (mm)
Station
Jan
Feb
Mir
Apr
M.y
June
Jujy
1 Alls
Sept
' Oct
1 SltinsfL}
10
5.7
113
1370
IWJ
172.7
134.4
105.0
|0® 0
4.®
40
24.5
46,8
—
1167
124 7
[70 1
215 1
154.3
122.6
jTs JiUwofJ)
40
26
9J
40 0
1272
91.0
159.6
170.7
1220
670
4 CrtJT.bc Lt i 1)
3.2
45
r 26.5
499
140.3
1484
215-9
]94.9
164 J
94,5
1 4OimbcU{3) 4 Gambela 4)
6.6
0
102
2
332 12
70.9 31
“i^r 124
169.8 124
129.0 M5
248.6
179 1
112
J 13 0
61
( J&mbeUtSl
0
0
20
39
116
86
159
J 49
134
76
(l) 1956-1989.(2) 1971-1989; (3) HaxaneUdsU. 19C6-I984. (4) KA, rxl^bilir., I9O619W. (J) BO*» reliability IW*-19*9
The above clearly indicates a rainy period between May and October and a dry penoci November and April. The resulting distribution during the dry and wet seasons, as defin in percent of total amount, is given in Table 4,2. below'
c
TAMS-ULG Bam-A kobo River Bxjio Integrated Development Master Pbm
47
Cb*Pfcr41 *
^utvstvmbs
VOLUME V
Table 4.2 Seasonal Rainfall Distribution
% 
Distribution
Dry________ _______
-A.
Mt-—
719562.19821
7956-1989)
(197349892
7956-19892
14________ J_ _____ _12_ ______ '        _ _
8___ ____  i____ ___
11
Wet
86
88
92
89
I
pok?? -
jika*o _
jjgnbcb
yinual rainfall vanes considerably A comparison for the above long-term period is given Table 4.3 Annual Rainfall Variation (mm)
pltang           _---------
ytanniuni__ _
, Aycrjse_—_
Minimum_ .—j
2504 0
885 1
——
185.2 654 8
Pokwo
1031 8
Jikawo Gambela
1 <14 A
1V74,J                     1 J J*t,U 796 6                       1082 7
544.3                       642 7
Maximum daily (24 hr) participation data is available at Pokwo A statistical analysis shows the Mowing results in millimetres
Mai. 2+-Hour Rainfall (mm)
1/20 year
1/10 year
115
102
Temperature data is available at Gambela (Station 4) and Itang (Station 5) at elevations 415 mask respectively
Minimum temperatures have been observed <^
ur n
'®
Gambela, 157 months at Itang
. 1985-88. Maximum temperatures
I
an<172  months  at  Jikawo  during  the  period  from  ioro-1988  and  for  134  months  at  tang
have been observed for 73 months at Gambela during during 1973 -1988 and 71 months at Jikawo during L 7. -
gaps been infilled
* synthetic record has been
as discussed in the Master Plan Annex 1A After infilling                       minima monthly and ann traduced dunng the Master Plan studies The resulting ma.
^^ptraiures in °C are given in Table 4.4, below.
* P ft. r ---- -------------------------------------------------------
**in Integrated Development Master Plan
48
Chapter 4PREFEASIBILITY STUDIES
Average Maximum and Minimum Temperatures (‘Q
J “    Feb         Mar       Apr           May           J“*  | July
1
GunteU'StaQ
Aver Max (I)
39.1
403
401
40.1
36.0
32 6
32 3
Aver Mm (3)
1 144 1
18 4
203
21 8
199
182
17.3
I lung (Su 5)
Aw .Max (2)
Aw Min (2)
195
20 5
20.8
210
17.9
170
16 8
1 170 1
jfcr^tsu 8)
Aw Mix (2)
j 356
37.9
38 1
383
34.7
1 32.6
31 1
304
1 Aw Mm (4)
IL2
193
191
2)6
| 21.1
21 1
21.1
(I) 198M988; (2) I973-19M; (3) 1974I9«; (4> 1975 19M
Wind speed has been measured at Gambela during 10 years from 1976 to 1985 The average monthly wind speed in tn's is given in Table 4 5. below
Table 4.5 Average Wind Speed (m/s)
January
1 5.2
July
5.2
February                        |5.9
August                             7.i                          1
March
t?9
September                      6 3_______________
April                                6.3
October                           6o — n
Ma\
|83
November                       5 4
June
5.4
1
December                       7 4              _____ —1
The above shows a very homogeneous distribution throughout the year
The maximum and the minimum average annual wind velocities observed have ranged between 20 17 ms in 1985 and 3 50 m/s in 1977.
Relative Humidify 
Relative humidity has been recorded at 12:00 noon at Gambela during 13 years from I 1986
The mean monthly data, in %, are given in Table 4 6, below.
[(?
TAMS-IXG Biro-Akobo Rher Basin Integrated Development Master Plan
49
Ch>Prrr 4VOLUME V
Table 4.6
Relative Humidity (%)
July
August
September
80_8
80J
October^
November
-479.2
—1ZU
669
December
63.1
73 3%.
e annual relative humidity observed during the above period ranged from 67.5% to
/unshine have been measured at Gambela during the 13-year period from 1975 to The average monthly records, expressed in hours per day, are given in Table 4.7, below
Table 4.7 Hours of Sunshine Per Day
January
7 00
July
August
4.31
5.15
|
February                                  7 77
Much
6 16
September                      5.77
Apnl
6 38
October
6.62
May
5 23                                   November
6 92
June
4.91
December
7.38
|
The lowest values correspond to the rainy season The average annual values recorded varied tom 5.42 to 6.83
Available mean monthly and total annual data on potential evapotranspiration (PET) and lake ' S ava^flb’e fr°m records at the Gambela, Pokwo and Jikawo Stations The
"?low C U meaj1 monthly and mean annual values, expressed in mm are given in Tabic 4 8. Potential Evapotranspiration and Lake Evaporation (mm)
M*r          Apr           M«y          June         July          An?
On           N<r*          D«        ToUJ
t
- ;bt
11
1 S’-
Li
? ET -
1 1
1
176        161           130           113          107          113          116           124          120         125       1561 0
123         ID            91            79. J         74.9         79 1         8U            86 8
■
172        162           134
.
113  109 107 118 127
120         113           93 8          79.1         76-3         74 9         82.6         88.9
17 5       1092 7
111          123         IMS
82 6 86 1 iam.6
149
104
1
152
106
115 88 I W 97 110 lot
805 $1.6 61.6 67 9 77 75 6
410
217
99 1637
693 11459
— ~  ______________________________________  _____ =.
c
=
^ VOr ftasih Integrated Development Mailer
50
Chapter 4PREFEASIBILITY STUDIES
4.2.3 Hydrology
There are 2 hydrometric stations in the lower Baro Rjver. The closest one is jtan Gambela station is the next closest station The drainage areas at these stations are 24 « km and 23,461 sq km respectively Data at Gambela is available since 1906 [  more
n
time, records are available at Gambela from 1967 to 1993 and at Itang from 1974 to
Several gaps exist in the available flow records ♦Annex IB of the Master Plan Report
These gaps have been infilled as described r
The mean monthly and annual flows are given in Table 4.9, below Table 4.9 Mean, Monthly and Annual Flows
Jut
Feb
Mxf      1 Apt
May     I Jtliir
July
Au<           Sept           Oct
I Nw     Toq
GunbrU
r—■
m Vi
•0.5           52 8
rcrai                  2156         £27 8
422 60.3 1310
IBO 156 J 5363
}74<l
969 3
678.4
1817.0
_________
905.9 1059.1 727.5
24263 2745.2 1948.3
295.9   "" 139.
f
"
767.0
3717
|i lL±ri|g
I' m’i's
rr^rti
KTiU
112           74 2         62J
300.3 1795 166 <
J 52 153.1
i06 410 0
376 7         664 2
902 S         103? 7   ”*773.3
976.5     |  1779.0
2418.0        2695. Ol   2076.5
7b 7" ~15?4
an 3 J     4271
IM'
About 85% of the annual flow at Gambela and 83% of the annual flow at Itang occurs dunng the flood season of May to October The remainder, 15% at Gambela and 17% at Itang, occurs during the low flow season from November to April The lowest flow is in March
Annual flows vary considerably The maximum. average and minimum flows recorded are given in Tabled 10, below.
Table 4.Id        Annual Flow Variation
I
Mu                          Aver
Min
Ratio
Gambela
__ __ —*—~~
rncm/yr                         15,780.0                 12.0160
7.470,0
2 11
nf/s
5004
381.0                      236 9
____ —-
Itang
- -- ------
mem vr
15,850.0
12,459.5
9.0800
1.75
i mVs
502 6                      395 1
2989                       ___ __ "
<n 1967-1993
(J) 1974-1993
A detailed analysis is found in .Annex IB of the Master Plan.
Flood flows are discussed in .Annex 1C of the Master Plan
Flood water levels were estimated in the Russian studies at the gauging stations and at t^ site locations. Data at the project area and nearby upstream and downstream of the ar given in Table4.11, below.
TAMS-U1.G BanvAkobo River Buin Integrated Devefepmeot Muter Plan
51
Cb*plfr'<njr* studies
VOLUME V
Gamula
Station
436J£_ 436_03_
43576_
435.&1
Maximum Instantaneous Water Level Elevations (masl)
424 44                    410.26
—
Itang Dam Site
429 60
429.50
429,30
429.20
Itang Station Jikawo Station
424.65
424 52
410 38
410.32
424.38
410_23
435.31
428.85
424 25
410.15
’ 435.14
428 70
424 18
410 II
Sedi’>tent Data
led sediment data is scarce and unreliable. A discussion is given in Annex IF of the ;U  pen  Plan Report For the purpose of planning the reservoir operation studies performed for \  s  pref«sibiliiy study, an average annual volume of 13.560,000 m3  has been estimated to Kcmilaie <n lhe reservoir
1.2 J Water Quality for Irrigation
AitKWgh data on water quality for irrigation is scarce, some data on water sampling and chemical analyses are presented in the Russian Master Plan Report, Volume HI, .Annex I. Climatology and Hydrology.
This includes the results from analyses of 51 samples taken al various locations within the Baro River Basin during 1986-1988
-lie number of samples taken, and for which chemical analyses were reported, include 4 samples Itang, u at Gambela, 6 at Bonga and 1 at TAMS' site
Th
e v^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
LSD^°cLaTsifitnCal   Conductivity  (EC)  and  Sodium  Adsorption  Ratio  (SAR).  according  to  the r Ms aj fo]! ^tlOn ^V£fs’de), the water quality for irrigation can be classified as CI -SI This
0
Tht
CU L
Si * ow Salinity Hazard (EC< 250 mhos/cm) W Sodium (Alkali) Hazard (S.AR<l0)
VE that:
r " tu
s
^'ater
No redu^'ty °
8;
f  r irriSation is excellent
CtIOn in crop yield is anticipated due to water quality
River
Dtvelopn>eiit M*3ter Plan
52
Chapter 4PREFEASTBIL1TY STUDIES
4.2.6 Land Resou rce$
Land resources were assessed in the current Master Plan based on data given in the n studies by Selkhozpromexport earned 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 to* suitable or moderately suitable for nee.
Pfevi{^
0
Soils in the area have been studied and mapped by the Russians at 1/250,000 scale Subscque~|
a combined map of the entire basin grouping the Russian map for the Lower Basin and 7
ARDCO-GEOSERV map on 1/200,000 scale for the Upper Basin was earned out in the Maj/ Plan studies and presented at 1 /l,000,000 scale (see Master Plan Volume 4) At this time the
types were reviewed and grouped This resulted in less soils types than the original Russian classification
The  soils  types  present  in  the  project  area,  according  to  the  present  Master  Plan,  and  tit approximate distribution in percentage of the total area are as follows
Soils       Description                                                                                                          % of Project
Class
4         Dlstric  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
Dystric  and  Entric  Fluvisols,  vanable  textures,  usually  deep  Slight
erosion hazard
10
Eutric Gleysols, seasonally waterlogged Low erosion hazard
11
Dystric 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 the test pits at various depths and tests were made in the
Area
27
59
11
1
2
In addition, laboratory
The laboratory tests on the soils samples included moisture contents and grain size (gradations Data from 10 pits in and around the project area, including 50 samples, were found Pits 
up to 2 m deep About 50% of the pits and samples are located within the project area and t remainder are located in the vicinity of the project area No data on the auger holes was rou
The results of laboratory tests from test pit samples are given on Table 4 12
A I 250,000 scale soil suitability and land reclamation classification map prepared by the Russ^ is available It contains VI major classes and 3 sub-classes (a, b, cj.
TA.MS-ULG Bartb-Akobo River Basin Integrated Development Master Plan
S3
Ch*Ptcr4ptffE
AS^STDWES
___________ _____
VOLUME V
j ■= Hassid according to the following clas«s
Classi Class II Class HI
Class IV
Class V
Class VI
Lands not requiring lirndamental reclamation mHsll„s engineering works 
Lands  not  requiring  fundamental  reclamation  m-, limitations in their agricultural use
.
neasures and special
ures but with certain
Lands   needing   runoff   control   and   improve™™,   r   l
properties 
Lands needing flood protection
'"Wvement of hydrophysical
Lands  needing  flood  protection  and  drainage Lands unadvisable for agricultural development
j- x main classes in the project are IL in and V, There
VI
are also small areas in Class I and in Class
L
54PRKFEASIBILm STUDIES
____________________v
Table 4.12 Itang Irrigation Project Soils Samples Laboratory
PH
No.
Sample
depth cm
Hygn>-
i motfture
Soil Fraction - %. Si/r in
---------
1-0.25        0.25-0.05             0.05-0.01      0.0141.005     0.005-hftA,
1687         0-16                      3 73                 21 52           39 50                    1231                    9 36                     5.25
17-27                    363                 20 44            40 39                   7 27
.226
| 3,49
38-48                  6 95                 20 60           22.30
-    — HflN —
6.04                 20.47          122 84                  5.73                    0 92                       14 52      -            3.7 35 .
6.53                  1 6 27                6.95
70-80
180-190               6.50                 17 94       . 29 49
1585         0-20                     9.20                 3.70
| 4 40
3 67 2.70
4.80 9.70
11.52
30 SO
30-40                   10 90              2 50              1.40                    3 50
7.50                    ■ 13.90
80-90
9.70                2.90              10.80                 690
4 |0
10.40
. 3552 "
-           46.6D r — ■
140-150             1160
1.50              1.10                    1.30                    10.60                    10 90
------- ‘i
64 R’i ' x
1 190-200             12 70          2.50              1.00
3.40                T 1.80
11.80
7 4 ?f ‘ ----— —
_i 79.50 f
1569        0-22
| 6.60
4.30            | 21.80                  HOC             1 3.10                      14 40
_
1 25-35                   6 30                3 60            i 18.20
13.40
2.20
i 50-60                     8.00                3.80            , 13 00                 9.30                    5 80
' 70-80                    800                2 80            i 18 70                  1450
| 0.60
13.50 1 12.70
16.00
45 50'
55 ?i.
47 4G
i 110-120              7 80                2.60             12.00                   1250                1 4,40                     8.70                 59.86
l 170-180           1 7 10                4.10              9.00                    10.90                  460
12.40
1572         0-29                    4.00                8 60              20.00                  11 50                  1880                   8 90
1 35-45 600
, 70-80                    6 20
100-110             6 40
150-160             8.80
7,80              12.60
7 20                     10.30
6.5O 23 60 0.70 1 8.80
4.70 1 13.90 11.00 530
'19.10 15.90
5190 Z , 3i« a
1 43.00 -:j i 44 50 4.
7.70
5 7 50
4.10            I 10.10                 3 60                    6.80                      10 30                     67 20 k
180-190             7.80                 490              7.50                   9 80
4.60
12 50                    61.1C
_ ] S6«          0-24
6.61                 3.91           1 13.58                 7 48                    7 97                      15 83                    5L23
24-49                 9 17                 395              1 95
49-90
| 9.17
2 77            I 634
0.82 12.50 15.64
i 57 3.01 15 83
90-123                10 25              2.49           n 6.oi                    4 76                    5 52
11.32
123-70           1 10.74               2 88             0.96                   835
3.00                     1217 _
170-200            11 73              2.22              700
5.50                   7.27                    9.19
1594        0-31                    12.00               200             6.90                    17 30                  10.20                  20.30 _
40-50                  1360               1.10             0.60                   6 30                   400
80-90                  12 60              1.60             6.20
r 5 60                     4.50
’ 150-160         1 14.40
12.80          20.80                 1860
1674         0-24 | 45-55
f«r-   | 11.63         43.86                  11 60
16.70 5.86
17.90 _ | 9 10
14.50 __ “1 11.90
1 4.70
8.60           . 26.32                 13.70                 396                     5.69__
65.14   £. i_7O48
' 69.80 72.74. J? 71.82
49.40
7Q.1C
- ■ i6.60 id ' ^T5l5_-d
_
AJIJ-71'jLS -ri.i
95-105          T 438
9,12          T 3071                 6 98
10.28
12.34
^33?0 —~n7 28 Ls
’ 150-160             460             7698                62 23                   1143
9 4!______ | 25.64_
156^         0-17
1.00                8.10           | 68.70                 10 ID                 230                     1 2 80
30^0                  1 80              • 10 10         58 30
3.30                   290                     8.30 __
“ ' 14.40
80-90                 1 80
9.20'
57 40                 8 70                1 2.50                    7.90__ _      -       480
140-150           0.60                5 80            74.60                  270
0.60
1682         0-16                   8 34                7 21             10.08                21.82                  11 55
25-36             1 7.53
9.13             16.49                26 47                 8 20
50-60                6 72                5 79            23.23                  1890                  14 53
l !,40
27.97
24  74_  .  . |2 25 __
215'       - life
■' 25-30-
70-80            ’ 0 20 110-120           0.20
158*3 0-14 8 02
55.88        | 28.36                4 19                   0 41
2.70____     “’^99 - -51
92.23          3.00
0.29                   0.28                L *          -
5.30             14.00                23 90                  14 50             1 17.30____ _
: 25 35
11.60             4.70            r i.4o
T 3 5-65 ’             11 70             4.90             12 10
9 ID 850
9.70 9.80
tf.jp. 52.20. frii 62 80
_____      _ L OP -J _10          , 10^0
4.50            3.10                1 10. tO
170-1                 12 70               2 30
it
1 .JW
ia
ian
J>8--
' !1.4_0_ 10.80
6.10
Scurtt. ScLkh^f^ntexpr:' Maser Plan Report. 1990
_ _________ _________ ___________________________ ___________ —-------------- ------- -
cli*p1 f r
TAMS-CLG Baro-Akobo River B«in
Development Mailer Plan
ool r„rrv STUDIES
VOLUME V
-
rea within the boundaries of the project area defined bv the main canal, the Bare
to iil S'05* 3 limit based on avoiding most flooded areas, covers approximated 72,500 ha covering appropriately 8000 ha is a flat area difficult to drain' This area
The =eniraJ carefollv stud,ed’ haS bt*n exCluded from the fanW area
«ther be
'tuch^'0       Looses'in    the       agricultural    development    or    partly    farmed    future    studies for OthC The remaining area covers a gross surface area of 64,500 ha
jdjjfliii*80'
ilaacs and other unusable areas, covering approximately 5500 ha, have been in ^dld0Vhe remaining gross area is estimated at 59,052 ha For the purpose of this report,
1
, |cd the usable area The net irrigable area, after deduction of the irrigation and
dris will be c irairvige syste
has beef estim
[    j roads, has been taken at 90% of the usable area The net irrigable
re ate(
. a[ 53147 ha, which is slightly in excess of the area anticipated at the
planning st 8
a
e
/17 Geology an^ ^^etechrtlcal
Tlx Russians produced a geological map of the region at 1/250,000 scale This Master Plan has rixiikced a regional geology' map at 1/1,000,000 There is no other geological map for the (tang
hmorthe rest of the project area A geological cross section 08-12 was made by the Russians ions the axis of the proposed Itang dam. This section shows the site to be in lacustrine-alluvial deposits of clays and loams overlying intrusive trachytes and syenites at depth.
The dam site is nor covered by aerial photographs, but aerial photos are available both upstream and downstream of the dam site and at the irrigable areas Aerial photographs are about 1/70,000 stae and the quality  is  not good. In addition, they  are over 20 years  old More recent photographs used for the 1 /50,000 scale topographic mapping were not made available Five drill holes by the Russians are shown on the geological cross section However, the logs, site and liboratory tests, cores, and report on the site investigations were not available for this report.
test pits were made by the Russians along the main canal, some distributaries and some ^°r  iraills   °nly  a  brief  description  is  available  There  is  no  data  on  sampling  or  on  field  or l8 ®°fatory tests.
is no information on construction materials for embankments, riprap, and aggregates
0,1 seismic          'S not se’smically active and presents a low seismic risk However, no data ctiv,t5 in the vicinity of the project area is available
Pr °j^i D veh
e        praent
' lVerSfied             0/1 d CropPiflS Patterns
in *e project area. The climate, water and soil lend themselves of croT^6 is possible tn the project area. 1 uc uiui<u -----------------------------------
P ’ Ending cereals, pulses, oil crops, fruits and vegetables, sugar cane, tedder
S
— -----—___ ________ ____________ —------
er Basin Integrated Development Mailer Plan
56
Chapter 4PREFEASIBILITY STUDIES
____________
V °L%
In order to develop agriculture, the lower areas need protection against flood in
need for an adequate drainage system to prevent water logging in part of the nA ^ere is w.
P’°J ct k
e
A diversified cropping pattern suitable for the project was prepared which inciud pulses, oil crops, vegetables, cotton, and fodder (ereen manure) The pronoun °S food «tta
is 166%
The crop distribution of this cropping pattern in percentage of the area, for the d
POSMcroPP”>gi«^
seasons, is given in Table 4 13, below
'
'
^arid-^
Table 4.13 Diversified Cropping Pattern
■ Crop
% Area
Dry Season                        Wet Season
Cotton
25
15
Maize
40
j
-
15
Sorghum
19
10
Soy Bean
10
10
Vegetables                                                                                           1                                          1
Fodder (green manure]
5
0
Groundnuts (peanutsj/oil crops
0
15
; Sub-toial
100
66
Total Cropping Intensity
166%
-*•'
1
medium size farms.
co ‘opCTanves well as eventually by
have   anywhere   between   2   and   5   hectsr^   mA™5    -S    nOt    been    ^eterrruned,   small   holders   miy 
operatives may have 20 ha or more
edlum size farms could have say 5 to J 0 ha Co
Food produced would have a readv mi- ■ t ■
eventually  exportable Commodities  <= wA El^°pia' Sorne quality  cash crops  may be
exportable.
1 such as cotton may be for the local market but may also be
soThy esebeacrnos,ps cocattonnggemne, rsoataeoannlaunBr nfA  F o-mdustne$, such as  j/ extraction plants from marzt
ar
o
for feeding rhe livestock Grain can V°?°n See<*s' PeanL|t-based industries. Fodder would be
need mixing with other poultry foods Sugar cane looks like a Dromisi economical size of a sugar nlaiAf
dcVei°P P
ou,!r V farms
-        - although grain *»?'
” ** ^SO beinS Proposed for this project The
Thus  the total area in sugar cane 'mated al 7000 ha. Three such modules  are envisaged
essentially  be conunerdal veZA iA u,tunatdy  r“3^ 21,000 ha for 3 modules  These would
holders or co-operatives under
under contract with the commercial venture enterprises
u
° fthe maF S™™ by
Sugar cane would supn|v ,lfl ,mnrirt
derivatives Molasses abv nmAA rc
« « 2„UI f«d Kpm of.
AMS.LLC
8 |OnaJ mdustry for production of sugar and possibly
“'° P'OdU“
U„.l.p„„, M„„, p&~---------------------------------------------- S7,7«4 '
57v OLLme V
sa•.lari<ed- -*3$?^ ™ * -"
, ha of the total 53,147 net area would be nlantAH
d for 1        x°:s
ibort
z ’ Irrigation Hater Requirements
Ration water requirements for the diversified cr .
MutcrPlan studies  These estimates  were based on the fie d " *ere esti™ted tn the
CtvpSif
for both ** and dry 
^determined by subtracting the 80% reliably mo^
^uirements of the crops in question. The gross monthly 
er ^^ments of indlviduaJ
water requirements
ra,nfaJI the field
obtained   by   dividing   the   monthly   net   water   requirements   bv   th,   ?,   Wa,er    ^^ements   were
ixdtr was taken at 50%, including field, distribution and con
' mgaUon efficiency The
rBcnts     the     water     requirements     calculation     for     the     divemfileffici«tcies.     Table     4     14 cropping pattern.
fer to particular project, the weighted averages for
have considered the mix of
akdalwn assumes 21,000 ha or 40% plantedTn d diversified cropping
net monthly initiation
I  8 ??
PU
58- Typical Cropping Pattern (DiverniHcd)
Tublc 4.14
M-
w "" --"‘"""21
Sei
March
Muy
June
.. 
,,K
Kwiifdl
field Wuler Requirement
Wt 1 JiLAS’M
Cotte** 25%
Maize 40% _
Sorghum (7% _
Sqy Bean JQ?*
Vegetables 1%
Green Manure 5%_
Subtotal _ 100%
Cotton 15%
Mmz* J 5% _
Smghnert 10%
Ctroundnuls 15%
Vegetables !%_
Soy I3can 10%
Subtotal 66%_             _! • 25 6
Total Crop Intensity 106%
field Wata Requirements _ _
i oo.n           128          f 40 -
49 4                  19
15                    20
42 5
J45
87 S~ ’
1
166 _       I _ ijo
■ 1 ~      12     5*
—
—
__
I -      12.0
---- ■ r
Oct
55
Nov
O
—
____ — - - - ----------- 1
--------- ----
------- -- -----
----------------
—
---- — —-- -
Ob
1.5
13.3
15
0 8
7
20
— ---      -
___
- - - -—
-
—
|      92 5 l 216 0
85  ' 1 1
I 267.0
1211         '  .32 5_
-.— T~
■
_ ?P
0
_ *16 ~5 —        28
o
57 8
•     16.5                           413
1         9.9               22
.13.2
2 2 "I ’
23.7 _ o _$
/ -
i— 1
t
L
1        6.6
0.4 0.7
5 5       |       |6 S
nun
<     125.6       ,
Nel [nigutjon l<equirement!^(2)
■mm                             T_ [25.6 •
•niViy______  _ | 1256  i
Gross Imgnt ion Requirements (3)     1
216 0
l 267 0
122 0
1220
l_      32.3       ,       90 1 --------t            —
h'
__
34.3 90 3
I
3
-m /ha_ _ _
-L/s/ha_
>) ^ey.vc
o
- — 
— -0
I
i
75 1
753
17.6
23 1
1 2
22.0
163.0
-------------------
163.0
163 0
i 25H
’ 0 94 r
932
2 12 5
320.0.
98 8
65 O
3.3
31 5.
7311
140.3
132 1
57.2
85 9
3.6
71 5
490 6
—
1221 7
655.3
1630                       6553
_0J2 J"_ 0
—
Iehllblllty
2) _Ji____ dd Wat    —leenram rciqituy. b ucmascendi on s m apinupsr eoxi ffemctativeel ry 80 yc      ainfallars~of records at Gambcln Annual means total annual. ^)_       50% imgabon efficiency, including field, distribution and conveyance losses and v»
P
0
1
1 506                       3260 0 58          ,
J .22 1
13/06
0 42
**   -------------- -------
—Iitblc 4-1S Ir/tnK IrrigMiun Project For Su^nr Cimc - Diversified Rolulion Mix (1)
, Jafl
/ Feb
i" March
April
Muy
June
July
Au
x
Sept
Oct
,   Mnv 
D
cc
Annual
/ / flrciivc Rainfall in mm f f J
/ 0
1
11o
«
25
too
118
145
166
1 10
55
15
1
0
i
S>32
/ Field Wafer JtequircnierilJt -
i
1
1
1
/ Sugar cane - nun
’ 120
J_ 120
1 110
1
no
i
oo i
100
100
100
HO
120
130
|
140
1360
I Net Irrigation Requirements -
j 120
120
| 102
1
85
0
0
0
0
_1
0
65
1 ns
140
747
/ .Sdgxw cane - nun
i
1
1
1
I
i Gioss Waler Requirements - Sugar cap
e
.1
1
I
1
|
I for 60% efficiency                                     200            200           170
1 Gros.i Requirements 1 diversified Croppi ng
for 50% efficiency (3) Gross Requirements Weighted Average
1—
_2512 _jU4_
142       |'      0             0                0                   0                  0               108 1
31 4_
1
0- 1 _0
244 0                0 0           11T6        146.4                2
L
192              233         |            1245
1
1
0.
0
1
150.6
326 0
1
1310.6
- mm (2)
-m'/ha (2)
146.8            86.8 1468            868
568 1 -+
0                 43 2      1 1672
288 8 1                 1294 3
__
l/s/ha (2)Q __________ Peak - 1/s/ha (2)
2307
2307
0.86
________
568                0           1176         1464                 0
0               432              1672           2888 |
0 61            0 32
_ 0 22
o ;     045            0 55
0_
12843
-------- -------------
—
L
0                    0 16    | 065 1-
t 08 111
1) For <0% rcUnbilHy based long-term revwrdi ul Gembela. Annual mean* total amount
2)   Aiauines 21000 ha lugxr c*nc pirn 32147 ba in diveraflcd tolnlion
3)   t’akulalion fa dlvcmriodLioppuppallwuw given in I able 4 14HANG IRRIGATION PROJECT
GROSS MONTHLY IRRIGATION WATER REQUIREMENTS FOR SUGAR CANE (40%) • DIVERSIFIED CROPPING (60%) MIX
(in VsJhi]VOLUME V
.^oir Operat,nn ^,u^‘es
l]J Reftr'‘ atjons were simulated with the HEC-5 computer model The simulation
- 0 res^'°’r opey , routing of
a
a 64-year time series Releases are made to meet monthly 
I: L s cf a 1110111 u .vn on Table 4.16. as well as the minimum environmental release of 31 m’/'s
Monthly Irrigation Requirements (m /$ per 10.00ft hectares)
3
jjble 4.1"
jjausQL—— FejntfQL---------
Miich. —
8 60
LA.10
3.20
i_2 20
July
August
September
October
5 50
0.00
0 00
160
I Agil ________
November
6 50
— -
0.00
4.50
December
10 80
Junt__—
fhs  reliability  criterion  used  to  assess  the  irrigation  potential  of  the  reservoir  was  selected  as follows for each month at least 80% of the monthly water requirements are met 95% of the time
Huai on the initial active storage in the reservoir shown on the Area-Capacity Curve (Figure 4.2) of 139 -I mem, the water releases can be regulated to meet the irrigation demand of the 53.147 secures 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 icthe storage Although there is  no specific and reliable data for the project, it is estimated that sediment accumulation in the reservoir could average 13 6 mem per year. This  could possibly resu.t in a significantly reduced active storage after ten to fifteen years
fjnher analysis  has  also shown that with the development of the hydroelectric  project regulating twrvo.rs in the upper basin, the need for active storage at the Itang dam becomes less and less "roiKL ' 05 'nc*’cate^ ‘n Appendix  U of the Master Plan, the two most promising hydropower
ftswctivel
^ aSin
Bare with installed capacity of 171 MW and 210 MV/'
good *   a5ed On evajLLar*on performed for this Master Plan, these two projects have a
'*‘ithn           01 rcCurn and are excellent candidates to be integrated in the interconnected system
rt SulitiOQ aext 10 l° VMrS that basis, the reservoir operation studies  evaluated the regulation wojid kd the two reservoirs, Geba-A and Baro This  analysis  shows  that this slOrageat th 1 C sufficient to irrigate up io 100,000 hectares  at the Itang site without active Pfojeq it apn»lan® dam Therefore if after several years  of development of the Itang Irrigation
!tOrigt wi|| Aw ■
reservoir is losing part of its active storage, it is likely that upstream
I,in ? eserv
r
O jr een ^eloped and it w’ould be sufficient to compensate the sedimentation of
gatl°n tn^rastructure
' l4ltl and ?StnJC,LJre CQmPrising the Itang Dam and the irrigation and drainage systems Preiniinary design was prepared for command of the 53,147 ha net project
■-
"^AknbT^r- ------------------- ■-----.----------------------------------------
er Basin Integrated Dtvelopmeni Mailer Plan
61
Chapter 4£ »"'
(wow) Ajpedeg jiowasay
Zun, ui eajy
Elevation in mete’« m STl D1125
VOLUME V
-
. a flow* pr°    °
tecti
n d lke
.
system  and  drainage  pumping  scheme  are  provided  to
of low ly^
one areas
Reservoir would be the storage and river regulating structure for the ltang [Jins Djrri . . The selected site, 25 km downstream of Gambela and 10 km upstream of
Projec nable balance between length of dam, storage and relocations The dam crest
str^es a r
flooding conditions at Gambela and the resulting live storage, while
ejeviion 's operalR-n, to be maintained will require preventive measures, such as  upstream
adeq^6 ‘^mbination of dredging and flushing of sediments  that do deposit within the
Storage. or 3 Cfaci]ltaie flushing, the dam will be provided with a gated spillway  with a sill
reservoir
| eve| The jam is sized such that, before loss of live storage, it can
Ration  co  ,atl!e    in-igation  water  supply  for  the  53,000-hectare  project  and  in  addition,  make ?rc vdea . nta| releases of 3 1 m /s to the over downstream.
3
Drainage and Hoad Protection Systems
The  irrigation  drainage  and  flood  protection  systems  were  laid  out  on  the  available  topographic mips 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 hang Dam and
would stretch along about 53 km, ensuring command of the project area Its design capacity of
jO.S mhs to 58.5 m7s is based on the estimated maximum monthly irrigation water demand of
i I litres 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 unJined earth canal was adopted However, because of topographic  limitations  and to assure command of Lhe irrigable yeas, the gradients  will range from 0 00004 to 0 00005 and lhe resulting velocities  will range fom about 0 5 m/s to about 0.6 m/s along the approximately 53 km long canal. A roughness
v l'ent 0,022 Was used f°r L^e main canal ^e main canal will supply 12 secondary 
,„^.n utaiy) canals. The main canal will be provided with a service road and with a number of u..,1,.StnJCtUrcs (offtakes, control checks, bridges drainage structures, etc.) Main canal freeboard
0,1113 from 0 6 m to 0.75 m.
'#:re   desi^"?^  C^na!s  and  a   number  of  tertiary  canals  were  also  laid  out  The  secondary  canals 
rdopttd   to   add   fl   3     Unit     Peik     rate     of     1     2     ,iues     Per     sccond     per     heclare     The     inCTeased     r3tc     was
- toij t0 Q Of>,
ln th«T operation. The gradients of the secondary canals range from
^^’esofth lnd the Vel»C’ties  range from 0.4 m/s  to 1.0 nr’/s. The maximum design 5 1 kn A C Secondary  system range from 16 m /s  to 15 94 m’/s. Then combined length is 
3
^baard   used0U8hneSS    Coeffici«rt   of   0   025   was   used   for   the   secondary   canals   Minimum tenant stn?^ ° 3 m The secondary canals would be provided with a service road and
S’nularty
,  3 Surf
’ ? tri
d ^naee system has been provided The system is formed by one main drain,
”' coftector drains and a number of minor drains. The drams are des ned for a
lg
K b — " ———k——_____________________________________________ . .
.
------- ■------—«-
° River Basin Integrated Development Master Plan
Chapter 4PREFEASIBILITY STUDIES
VOl«Mt '
v
capacity of 1 5 litres per second per hectare, which is based on the concept of dewat • 
vear return maximum 24-hour storm of 115 mm over a 9-day period
er,ng a 2t,
The main dram was designed for a 0 0003 gradient, velocities ranging from 0.77 m/s t r
and 0 5 m freeboard The roughness coefficient used was 0.030. The main drain
1,11
km long
dbclll
The secondary drains were designed for a 0 0005 gradient, velocities ranging from 0 4  -
m
m/s and a 0 5 m freeboard Roughness coefficients used were 0 030 for the longer
exceeding 5 m’/s capacity and 0.040 for the small drains with lower capacities The tot 11
'
of secondary drains would be 79 7 km
‘
Typical canal sections are given on Drawings IT-8 and IT-9
Additionally, a typical irrigation sector, having a gross area of about 1,800 ha, was studied ba<<- 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 and 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 quatemir. distribution and drainage systems. The net area was estimated at 1,631 hectares or 90 percent of the gross area The tertiary and quaternary canal distribution system was sized for a peak flow rate of 1 5 litres per second per hectare The drains were also sized for 1.5 litres per second per hectare Roughness coefficients used were 0 025 for canals and 0 033 for drains Gradients ranged from 0 0001 to 0 002, and velocities ranged from 0 3 m/s to 0.6 m/s Freeboards used varied from 0 20 m to 0 30 m The system w ould be provided with service roads and appurtenan
r0
r
structures
Similarly, a layout was prepared for the on-farm irrigation and drainage for a gravity system The systems were sized and a cost estimate was prepared for the purpose of deriving a unit cost per hectare for the on-farm systems The layout is shown on Drawing IT-14
A dike system was laid out along the right bank of the river in order to protect the flo°d P ^ 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 intg return flows, 9 low-head pumping stations and a flap valve would be provided The p stations would be equipped with electricity-driven vertical centrifugal pumps and
electrical and mechanical equipment The pumps would discharge to the river at vana stages by means of pipes built through the embankments and flap valves
An electnc power transmission system would also be pan of this project The sy stem, c of 33 kV and 13 kV lines, would supply the dam operating gates and the pumping
TAMS-ULG Biro-Akobo Rhcr Basin Integrated Development Master Plan
63
Ch«P'f,Jvolume v
fens*
111
Ejtn-
*Z
^?.*.>**
1
-■ p[f itC ' ®
were estima^ generally as discussed in Annex IQ, Water Resources Cos. ,..d expressed in USS (Jan 1996), are given in Table 4 17
fnef3111
unit costs usea, h
a     ]5%   allowance   was   estimated   for   contractor’s   mobilisation   and   temporary 
Elt ^ditton' airf^1011
facilities
costs were arrived at by multiplying the quantities by the unit rates and then ^“S^owance   for   physical   contingencies   and   finally   a   10%   allowance   for   engineering adinii-1' fl
r muil operation and maintenance costs were arrived at on a percent of construction costs tais, is follows’
Description
%
Civil Works
0.5
Mechanical & Electrical
30
Irrigation & Drainage
15
Transmission Lines 
1.0
Fewer 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 eamared value of the produce based on commodity prices, as determined in Annex 3E, Economic i-J  Financial Analysis, of the Master Plan More detail is  given in the Economic  Analysis ”eser.t&d in Section 4 4,4,
------------------------------------------------------------- aim ^tegrated Develop meet Master Plan
Chapter 4prefeasibility studies
Table 4.17
T Item
Unit
Rate
a)           Irrigation Systems
i                Cleaning Irrigation
Hectare
J m
600 n
Stripping
i                Excavation, common, irrigation
Compacted fill, mairVsecond incl. hauling         — x    5&T
m
—------ JU  1 $n" 3 5tT
j                Compacted fill, other
m
Concrete lining & formwork
m’
4 00 120 00
I Wire mesh, welded
m3
Tso'
Roadwav gravel
m3
““5
m
25 00
Roadwax base course
1               Structures
18 00 ’
%
10%
b)           Dam
r       Excavation, common
Road improvement
km                 39.546.85
m
3.62
Rock excavation
m
904
Borrow excavation, common
m                             339
Borrow excaxation. rock
m}
4.80
Unprocessed fill placement
m3
2.26
Processed fill placement
m3
6 78
Hauling fill material (over 2 km)
m'/km
051
Impervious core material
m3                                        11 30
Fillers, drains, transitions
m?
16 95
1
Riprap, placement
m'
5.65
1
}
Mass concrete
m
9039 _
Structural concrete
m
12994J
Form work
m
5085
1                Steel reinforcement
T
1,242 90-
1 1            Drilling for drains
m
56 50_
1               Drilling for grouting and drains
m
79.09..
.Anchors, incl drilling and grouting
T
14.91A81_
Grouting
T
564,96
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 with a maximum height o metres and its crest at elevation 436 0. Although there is reportedly outcropping r0C spillway site, most of the length of the dam is expected to be founded on deep alluvium, upstream impervious blanket will be provided for seepage control.
TAMS-ULG Baro-Akobo River Basin Integrated Development Masterplan
bout I4
Cb-P‘<Hstudies
VOLUME V
■ take is on 016 nghl bank and wU1 ** pI,-uded len 3x1 5-metres sluice gates 
itna^on111
r level js at
428.5 based on minimum water level elevation 429.0 at the
in losses
Lhe nver The channel is designed for the 1:100 year flood The earthfill dam will o?J hend * sides of the channel and the concrete spillway constructed at the same lime
diverted over the spillway and the remaining portion of the dam fill will be The nvtf J; channel The spillway sill is so low that if any problems should develop
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  TT-I  shows  the  dam  cross-section  and  Drawing  IT-5 presents the length profile of the dam and the spillway cross section
/rrigalwn
An overall layout of the irrigation and drainage systems  and the flood protection dikes  and pumping stations is shown on Drawing IT-2. This drawing also presents the axis of the dam and the irrigation intake location.
The main canal will be approximately 53 km long The canal capacities will range from 58.5 m7s n the origm at the intake on the right bank at the Itang Dam and 10 5 m /s at its lower reach The
J
ifflgth profile of the main canal is presented on Drawing IT-6. The typical cross sections are in Drawings IT-8 and IT-9
tbe * range from 18 m’/s to 15,94 m’/s The typical canal sections are the canal sections
•
Cnvp. “ 
3J31VILL3 tuiu
----------------
"447 net hectares A tvnical lavout of the proposed gravity system is secS? ^kes A lenSth Profile of the dike system is shown on Drawing IT-7. A
'° niS Presented on Drawing IT-10.
'
66PREFEASIBILITY STUDIES
------------------- —---------- -
Nine drainage pumping stations with capacity ranging from 20 kW to 260 kW the purpose of dewatering the area behind the flood protection dikes The Pr° °sed[.
p
Drawing IT-10 indicates their location along the dikes A typical section is Dr?^ pr°filt
IT-11
4.4.2      Cost Estimates
A   construction   cost   estimate   was   prepared   for   the   proposed   project   scheme section 4.3.5, above
ted °n[)r^
15 d«cribed8
The estimate is  presented in Table 4 18 A separate detailed cost estimate was  prepared f i Itang Dam (Appendix  4-1) and was  subsequently  incorporated in the project cost estimate Tk dam cost estimate is given in the appendix and referred to in Table 4.18
A summary of costs in January-1996 US dollars is given in the following tabulation
Preliminary
Itang Dam
Access Road to Dam
45,431,000
50,064,000
40,000
Main Canal
24.143,000
Secondary Canals
20,128,000
Main and Collector Drains
4,335,000
Flood Protection Dikes
14,865,000
Pumping Stations and Flap Valve
975,000
Transmission Lines
2,850,000
Ternary, Quaternary and On-farm System
107,091,000
Levelling
26,573,000
Clearing
6,378,000
Subtotal
302,873,000
Contingencies 20%
60,575,000
Engineering and Adm 10%
TOTAL
36,345,000
399,793,000
In addition, an estimate of annual costs was prepared for the project This includes constructs s in accor ce with a proposed project schedule given in section 4 4.3 and operation and
constnjction 11,6 costs for the penod from 2001 to 2020 and thereafter, in USS (January 1996) are given in Table 4.19
4.4.3   implementation Schedule
implem'n,a"°"
construction activities
was prepared Thia mdicales both pre-eonstntcuo"
aCtn,1t,es inchjde studics required prior to construction up to the feasibility sU8t project finance actmties. negotiation of concession agreements with commercial agribusin*
r ™.
.   y“1,on of desi8ns, specifications and bid documents for construction
and p rep
Construction is divided in 3 phases
TAMS-UIXS Baro-Akobo River Basin Integrated Development Mai ter Plan
67
Ch*Pcer4;(LrrV
stuoks
VOLUME V
Irrigation Project Coat Estimate - US Pollan (Jan.
— *         ~ 
_____  UaJ* _Qttnntity fl'nrtPrkg I
LS.        1
___ _ _____ _ Cut       1
liras
LS
I
11
r-sp,llway-
45.431 014 45 431 14
50,064,251 50.064,251
iunt Dsnii. tfna«_u<* <LL
1 -cSw w D«m J>._----------------------— At***5-^
— Uffil C"**1
11
F)i l, co^P* *
07m thick
Clearing
5ljucNru  and  rmsc-_ Canals
Edition, common Fill, ctHTipacicd
1
LS.         I
4.900.000
i. Ji 42 (3 44
-5
-6
y 5 5 i JJ
7.4 
39,547 2.5
56
1.5
250
180 6000 2300,000
Scnppn ?
GnTri midway 0 2m thick
Base course 0 3m thick
.
m1 n? n? m
ha LS.
m3
m’
m3
3
m3
m
I
1.100,000
145,000
39,000
100,000
J co
I
1.147.000
1.851,000
300.000
6|,DOO
157,000
2.50
5.60
1.50
25.0
18.0
55
5.6
CJcanng Structures nusc 10^°
ha
-------- ----------
LS.
440
I
600.0
1,829.810
264.000 1.829.810
~N€a4n ejxi Collector Drama
ExoivadoEK CommOTi
m’
1350,000
2.5
39,547
(24,142300) 12350.000 6,160.000
217300
975.000
L800,000
240,000
2300.000
(20.127,910) 2,867 300
10365,600
450.000
1325,000
2.826.000
(4335,000)
3,875,000
I Clcanng
Structures and tnisc.________________________
ha
LS
LS.
L.S.
LS.
100
I
I
1
I
6C0
400,000
60,000
400.000
Flood Protection Dikes (2)
Dike No. I
Dike No. 2
Dike No. 3
6390,000
6.480,000
2.095,000
(14.865.000)
6J9O.OOO
6.480.000
2.095,000
Pumping Stations and Flap Valve
1
IPS. No. 1
kW
(975,000)
16,000
2
P.S No. 2
kW
48,000
*
P.S No. 3
4
kW
208,000
P S No. 4
kW
80 £03
5
P S No 5
kW
168.000
6
PS.N0.6
kW
120.000
7
P$No.7
kW
80.000
S
?SNc    8
’
p SNo.9
kW
56.000
,C
.
L.FUp Vjve
kW
184.000
LS.
20
60
260
100
210
150
100
70
230
1
15.000
1
Gtohek     T     ^umes     power     at     Oambefa) ^_^g(33kV)
fan
53
22300
(2,850300) 1345300
fan
60
JO
22.500
1,410,000
fan
29.500
J95£00
?! S'XS’ T'rDraiIlagc Systems I‘
Sy5telB
■ ' ^?!y^_(3'i
_
——-—_____________ ___
area )
ha
ha
ha
ha
53.147 53J47 53J47
1O.63O__
755
(107.091305) 40,125,985
_U6O_______6_6_X_532O 500      _26373300
600
^ CCr''1'8 Atamstrauon 10%
_ 637000
302.873,427
60374,685
363,448,112
399392324
Chapter 4
Basin Integrated Development Muter WinTable 4.19
g Irrigation Project Annum
-------------------- ------- --------------------------------- O AM CoaU
Total
Capital Co»t«
Civil
25.976 37.S25 41,455 17.324
6,248 _!_2j593
12.395
MAE
0
0
1.742 1,163 _
0 0
200
Tran*-
minion
Line*
0 _0 
4,124
I Irrigation 1 Total
A
i-
Drainage
0
5.080
I VL732
17 732
] 14.997
8,184
10,919
17,732
17,732
14.997
8,184
10,947
17.831
17.832
15.098
8.285
8.285
5.91J
0 0
_____ 25.976 42605 60.929 40
21,245 20,777 23,514
Civil oZZ
MAE 0
0
129 88
317 20
524 48
0
0
0 52 26
Trnni- mlssion
Line*
_ 0
0
0
6_____ 0
41 24
41 24
A 1 94
1996)
Irrigation
A
Drain age
0
-0
0 76 20
342 18 608 16
Power
0
0
0
0 _____ 50 00 50 00
o~" 0
129.88 393.40 968 92
1.397.65
Total
Amount
25/776 OO 42,605 00 61,058.88 40.736.40
50 00
50 00
22.213 92
22.174 65
25,167.85
19,571 57
2012 2013
2016 __ 2017 2018 2019 2020 A. thereafter
5,529
5,000
17.732
17.732
14,997
13.811 16,576 22.931
23.044
13,098
8 285
5511 0
611 10
642.34
705.30
767^8
767.28
767.28
767.28
795 41
823.06
84806
871 37
871 37
871 37
87.15
87.15
87.15
93.15
93 15
93.15
93 15
93 15
96.15
99.15
106 56
106 56
41 24
41 24
41 24
41 24
41 24
41 24
41.24
44 27
833 12
955 88
1.11966
1 185.64 1.651.62 1.876 58 1 999 34 2.163 54 2.431 01
2.69849
44 27                  2,924.96
106.56           44 27
3.049.23
50 00
50 00
50 00
50 00
50 00
50 00
50 00
50 00
50 00
50.00
1,653.85
1,839.57
2,071.33
2,337 31
2.603 29
2.828 25
2.979.14
3.173.99
3,469.46
3 770.69
3,997 16
4,121 43
19.803 33
17,334.31
16.411 29
19,404 25
25.910 14
26.217 99
18,567 46
12.055 69
12,282.16
10,032.43
0 871 37 106 56 44.27 3.173 51
0 871 37 106 56 4427 3,262.17
SOCK) 50.00
4,245.71 4 245.71
4.334 37 4,334 37
J„ rrt sTt'»rcs
VOLUME V
------- -------
Irane   Darn,   ih*   uPPer    P°rt'on    08    5    Ion)   of   the   main   canal   and   all   otter 1 1«l"des/a,   eloprnent   of   17.000   U   mduding   a   6r>t   7,000   ha   module   for   commerce
feature* forae , , 0 000 for diversified agriculture by small holders
l^aof*""0”
Hr middle portion of the main canal (24 km) and all other required features for
^[1 include51          . a development, including a second 7,000 ha module of commercial sugar
dditio^ 17'°\ <ecOnd 10,000 ha of diversified agnculture development bv  small holders 
^etadoaa*5*’
.
m includes the lower portion of the main canal (13 km) and all other required
Finally. Phasc djjtional 19.147 ha, including the third 7,000 ha module of commercial sugar
features for an a
options
.    development    period    for    each    of    the    3    phases,    including    major    works.
The constru , c on-farm development, would be as follows:
djjtfibution a™ draK,as
i  al 12,147 ha of diversified agriculture operations 
addit on
Phase I
2001 -2007
Phase II
2005-2012
Phase Lil
2011 -2018
Project  finance,  private  concessions  and  design/specs/bid  activities  would  precede  the  above construction and development
Irrigation construction and development would proceed at a rate of about 2,000 ha per year for each commercial and non-commerciaJ  operation with a lag between construction and on-farm development Maximum production would have an additional lag, as  descnbed in section 4 4.4, Economic Analysis
The proposed implementation schedule for 1906 to 2018 is presented on figure 4.3.
4^ Economic Analysis
irrigation project consists of two separate areas of cropping with one area under
CrC1 SU8ar the other under smallholder mixed agnculture
The Sjoap i,~ii
intense win l nS'St of a lo,al of 21,000 ha. broken down into three 7,000 ha blocks  Cropping
■9 will be
T^ itltxhH farm'
'■Enables fo<M WiU consist of the following crops: cotton, maize, sorghum, soya bean, in the dP' " 411(1 oilseed’ and will be cropped at an intensity of 100% in the wet season, and
sea5°ti, for a total of 166%.
tn?Sh^n m^T ki°f °UtpUl minuS the 0051 of 0"-fann inPuts)to lhe fanncr for 630(1 °f thC
3£ . and thd 4'2° This ,able is bascd uPon CTop bud$ets laid out m Appetldlx 5
e etailed computation shown in Appendix 4-2 of this report
_______________
Basin Integrated Development Master Plan
70
Chapter 4tTANG IRRIGATION IMPLEMENTATION SCHEDULE
NOVEMBER 4.19H Umx
FIGURE 4.3
I . 1
IM
'l • C>MI i 11 huHH -—<*•
■.
W -y______VOLUME V
Table 4.20
Economic Return of Crop (Birr/ha)
’ Year 2
Year 3
Year 4
Year5
6.770
"3,451
4,563
5,352
5,352
2,066
3,896
4.307
4,307
1,535
3,074
3.878
3,878
ipse? -
yjjeuhl^—
£129) ,350 'U28 "865
J,_877_ 2.681 2.684
(7.268)
97
2,353
f 4,514
2,120
2.363
2,606
2,606
5,170
7,659
10,148
10148
3,412
4,083
4,811
4,811
oas§L—■
15,321
22,024
22,024
22,024
iprCan«__.
DOf  cropping  for  the  proposed  irrigation  project  is  summarised  on  Table  4-21  The ^^5  shown  as  the  number  of  hectares  brought  under  each  of  the  crops  each  year  As  can ^  ^from  the  tables,  the  first  acreage  is  brought  under  cropping  in  lhe  year  2004  and  then bjTop gradual ly For sugar it is 2016 before all of the acreage is cropped, for mixed cropping ^acreage is not cropped until the year 2018
Table 4.21 Cropping Build-up (hectares)
Yur         Con on          Marzr          Sorghum
Soya        Vegetables
Fodder
03 Seed
Sugar
,i
800              1.100
580
400                40
100
300
2300
3005          1,600
2.200
1.160
SOO               80
200
600
4,700
:xe            2.400
3.300
1.740
1,200               120
300             9CO
7.000
axr
3,200             4,400
2,320          1,600               160                400            uoo
7.000
UBS
4.000             5,500             2,900         2.000               200                 500           1.500
7.000
4,800 5.600 j£lOO
7200 2.000
J.SQQ 9.600
(0,400 (Uro
(2XKJ0 12.859
^^4.22 the sum
6,600            3,430          2.4130
7,700
8.800
9,900
1 1.000 J2,ioo
13.2 CO 14,300
13,400
(6,500
1L681
4.060 4.640 5.220 5.800 6.3 SO
6,960 7.540 8.120 8,700 9,323
6.000
6,499
600
643
1,500
1.607
4,&22
9.300 11.7QQ— 14.000
14.000
14,000
16 JOO 18.700
21,000
21.000
j 21,000
21.000
v S tk SraduaT °f build'uP of benefits from the cropping is shown This combines tw o years fOr ‘^crcas« in acfeage and the increase in yields that occurs over a period of
Jiiif- ^PPing the h 35 's brought under cuitivatiorL As can be seen from the table, for ' btlil[S of vi in tS afc not f^aximsed until the year 2022, while tor sugar, with a much
s . maximum benefits come earlier, in the year 2018
jn.,
---------------------_
_________ _____
er Biuln Integrated Development Matter Plan
71
Chapter -Iprefeasibility
studies
z
Tabic 4.2
2 Benefit Build
-up (million Bi
rr)
Year
Cotton
Maize____
Sorghum
Soya
Vegetables
Fodder
Oilseed
Sugar
2004
2008
2012
(0.1) '
0.7
03
0.1
03
03
109
23.2
9.1
53
0.5
3.6
36
32.5
46.7
19.1
11.5
I (75)
1542
292 9
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 on.i~ cost of this production As there is little or no established cropping in the area proposed fa 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 ax are shown in Appendix 4-2, first of all as financial costs in millions of Dollars and then is economic costs in millions of Birr A shadow exchange rate of Birr 7 47 to the Dollar is usedr 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, th cost-benefit stream shown in Appendix 4-2 gives us a set of net benefits which are the protect benefits after all costs have been met This net benefit stream gives an Internal Economic Ratec Return to the Itang Irrigation Project of 13%.
<4.5 Environmental 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
•   a road system for servicing the hydraulic infrastructure.
‘"‘
he
, r’™ 
"
®hi 14 m and
290  lts           cuWc “ «
construction will
an
loe,,-’ dI maxunum level is at El 431 a
» esoma.eo ,
0 b(                “ « ET«M. m The mean M„la, flo„, „f
™ d'>“™eam ofGambela Ila**
Cn8th °f thc dam is 5’°°° m-,ls
embrnikmo,,
,ts nonral minimum operating level a1
lh Baro
/
„w'
»
S '“h"8e fra” *be dam w|| bc dl„ned >o inhale . *
TAMS-ULG Baro-Akobo River Basin Integrated Development .Master Plan
72VOLUME V
^ely 53.000 hectares The ™ caul will be designed 10 Mnvey ,
-
1>adi
jcusses 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
. Xt« ci oni Scant flood attenuation is anticipated from the f^PTUCHt nrwnhrkrt
nol   Sliryeyed  other  than  in  the  context  of  the  1995  JTbcx/y  Biomass  Survey  by  Tberiauh. Using his results, the reservoir lies in an area whose potential dry woody biomass lies between K  ind  30  L'ha  For the area of the  reserv oir (71 km‘)t  this translates into a potential fuelwood supply of between 71,000 and 213,000 tonnes At 5 Bin per 20 kg bundle of fuelwood, its gross resale vahe. exclusive of the cost of collection and preparation, is between 18 and 53 million Birr (USS 28 and 8 5 million)
agriculture   and   grazing   Itang   reservoir,   because   of   its   extensive,   gently   sloping shores,  offers  potential  opportunity  for  recession  agriculture  and  grazing  during  the  dry  season
Sxh areas have been tradi tionally 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 < sorghum dominant) and pastoral systems. The section on subsistence agriculture in the project 5ctung describes the role of recession agriculture, which provides between 2 and 3 crops annually 
^ese opportunities are nnr in
qrmnihnrp hut rnmnlement it in wavs
down canals, destroy crops, and starve unless their numbers were kept within
^1^taint rCSU*1 frQ|T* livestock  grazing in the reservoir area. Exposed on the surface and rot ^anginsTrh6 CVaporat*on insolation, horse pats, cow pats, even elephant pats  dry  out and Ccnce^tion<i T noxious components  to ones  that are more or less  benign The use of high ^Period off ° ^eworrnillg medicines  can produce pals  that are toxic  to maggots, extending
required for decay io take place
Basin Integrated Development Muter Plan
73PREFEASIBILITY STUDIES
vo x
Negative environmental impacts and their mitigations
Large dam projects cause irreversible environmental changes over a wide geoer
thus have the potential for significant impacts The area of
influence of a dam n • ***
r
from the upper limits of the catchment to far downstream While there are direct
impacts associated with the construction of the dam, the greatest impacts 
impoundment of water and alteration of water flow downstream These effects h ^°Tn
impacts on soils, vegetation, wildlife and wildlands, fisheries, climate, and human
the area The dam's indirect effects include those associated with the building
of the dam, the operation of the reservoir and the development of agricultural ind10’*0’*'
municipal activities made possible by the dam
The   negative   environmental   impacts   that   result   from   dams   and following
•     Construction camp,
•     Roads,
■ Dam and appurtenant works,
•     Dislocation of people,
•     Loss of land
Loss of historic or other features,
•     Loss of wildlife habitat. Proliferation of aquatic weeds. Deterioration of water quality',
•     Reservoir sedimentation,
•     Riverine fisheries.
Water-related diseases,
•     Conflicting demands for water, and
•     Increased land pressure.
’ stnit t
reservoirs could include
Construction camp Construction camps usually comprise quarters for between 200 and 600 ma. and contain showers, cooking facilities, toilets, generators, fuel dumps, cement machines,
areas — everything needed by a small town. Their design is usually temporary, although
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 possible, trees should be left standing to provide comfort for the workers as well as supp y source once the camp is  decommissioned If people are to be resettled to provide spa£* camp, the resettlement policy currently followed by The World Bank should be follow
The amount of natural timber harvested for camp construction could be moderately sigfl no precautions are taken Ideally, such timber should come from the area ° uon e impoundment Outside that area, its impacts are identical to those of logging d
native vegetation and disturbance to soil and water To the maximum extent possi e, should make use of such materials as plastic and metal sheeting, plywood and concre
TAMS-ULG Baro-Akobo River Baiin Integrated Development Mailer Plan
74VOLUME V
Dowerhouse will create insignificant impacts l0 tt]e enwonment (<) .
_ dectncal P°
,e C-\m, powerhouse should be located away from residents and receive regular
■ to 3
'<tcruince
nD |y   if   it   is   a     larCe     carip     codd     create     drawdowt'   ‘o   levels   below   the   tettoms rhe   camp  waier   Effected  households  could  be  compensated  by  receiving  camp  supplies  or  by The^P
o f^ yWe           weuTf^ofed           Ideally’       nCarby           hOLSeholds           shouJd           t*       relocated       before       the ^ ng ’^enTofconstniction.
id be incinerated at a location removed from the camp and nearby households Solid '*'aSte 5^wage facilities should bear in mind w hether or not the camp will continue to be
The & ‘l^ °
s
Konunissioning It it is to continue in use. then primary sewage treatment is 
otherwise, extensive septic systems might be permissible.
yhe construction of the itang Dam requires 1 km of road improvement Roads have
ti to be an important contributor to soil erosion, primarily because they concentrate and
^bute nwoff as channel flow' rather than as uniform overland or subsurface flow
Access  roads  will be constructed to a high physical standard (compaction, gradient, surface tardness) in order to accommodate the weight of heavy equipment As these roads are likely to reused for many years following dam construction, the major structures should be designed to safely pass the 25-year flood and the minor structure to safely pass the 10-year flood. Temporary tods  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 apioitaiion logging, farming, hunting. High standard roadways  should avoid intercepting primitive areas, national parks, controlled hunting areas and locations of exceptional historical or cultural significance unless the means to control trespassing to these areas are available
fft mitigations of the potentially negative impacts of roadways rest with competent engineering follX Lon8ltudinal drainage is likely to require a raised bed and ditches Cross drainage should
c ^aiUie’s aRd be designed to accommodate debns as well as water and sediment the QUtQ°WS should be constructed to a level below' the stream bottom so as not to interfere
they               °f aquatic life Culverts on steep slopes may require an energy dissipator before **Project °nt° un?TOtected land A Soil Erosion Control Plan should be developed during
^rollins and Precedc Che onset of construction Its purpose is to provide guidelines for erosion, sedimentation and pollution
Sql1 Erosio
ideniifi^ °ntr°l Plan Ascribes the location and tvpe of controls to be implemented it
i Probl
resourc«. such as wetlands and pnmal forests, that require protection.
7 1 sh^ld con SUCh as ^ghly credible soils and unstable slopes, are clearly marked The
2 hin(1 location ?f? !
S C draina8e information, such as stream patterns, watershed areas, and the
n he follow^ hydraulit; structures The erosion control measures should be in accordance Principles:
Basin Integrated Development Mwtcr f*'*11
75
Chapter 4PREFEASIBILITY STUDIES
_________________________________________________________
Limit the time and area of exposure The potential for erosion is greatly r
size of the disturbed area is small or its duration short In some instances staKr
take place as part of construction - it would be wrong to wait until the final * established
Retain sediment on the site. This principle is achieved by using devices that filter
from runoff or that detain runoff so that heavy particles will settle. It includes^*5 materials such as silt fences, straw bales, brush barriers, and sediment traps andb^
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 berms and channels might be required to divert clean runoff around the site
Dive^,
3
Dam and appurtenant works The total quantity of all material needed for construction of - embankment is estimated to be 3,450,000 nr' Most fill will come from the reservoir area
its potential impact is mitigated by inundation Approximately 210,000 m  of riprap are &
required, possibly to be quarried from the koppies that scatter the plain The koppies are not t common that they lack uniqueness, however, particularly in terms of wildlife habitat They Mi
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 te dislocated by  the Itang reservoir. The World Bank  resettlement criteria for dislocated peopr should be followed The fanner 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 phi assets (estimated at USS 500), they become USS 884 per household or USS 628,000 for the 711 households
Loss  of  land  The  reservoir  will  impound  71  km2   The  worth  of  its  standing  timber  as  dry' biomass has been estimated in a previous paragraph The previous assessment shows that ■!. 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 worn of the lost agriculture (less assets) is 570,000 Birr (USS 91,000) per year
Loss of historic, cultural or aesthetic features These components were not assessed at this lewl of study but remain for feasibility investigations
Loss of wildlife habitat Itang Dam, reservoir and canals occupy part of the northwestern of Gambela National Park The park is severely degraded and its wildlife population re
However, the wildlife and habitat are issue that require additional study during to351 investigations
Much of Gambela National Park is already occupied by a state farm and Abobo & reservoir, and is dissected by connecting roadways Poaching by refugees and the Sr reported in the area
TAMS-ULG Baro-Akobo River Basin Integrated Development Master Plan
Ch*P,er'<VOLUME V
V*'
n faauat!£^^ Itaf|g reservoir is shallow fwiti,
^S~n\km;reservoir area). The water will be warm, oxvee^tM? d€pth of 4 1 n>e-r«) <^de W habitat for aquatic growth DraX^S X *
- f'lbjh -      ■
oarticularly if the landscape is used for controlled 544500 ™
J
Staging and agriculture
v a/,Ow
♦ ■«
Miter quality- Water quality is affected when targe amounts of tropical
hv new reservoirs The two important parameters to the process are the
would place the reservoir out of the severe risk category. For the purpose of this
^tfea^bility^tudy,  it  is.  however,  recommended  that  the  reservoir  area  be  totally  cleared  of  all ^degradable biomass.
Ltanz  mil b« warm during the low flow season, contributing to low dissolved oxygen concentration and thermal stability. Wind turbulence will agitate the surface and possibly contribute to some mixing of surficial water layers, but this could be minimal if aquatic growths develop a wind break along the surface
Anaerobic conditions will prevail along the former thalweg and in the vicinity of the maximum cross section Oxygenated waters may only be several metres deep, thus the effects of anaerobic icciy may not be apparent along the reservoir fringe. Because the irrigation intake is along the ii-n side rather than the centre, the problems of reservoir water quality may not be apparent to
■fusers during the early irrigation season Later in the year, when chemical processes become
10 r
’ " active due to increasing water temperature, problems of taste and odour may increase
?u
be
“ wntaticnofih^ • 
to  su   re^ervoir  is  anticipated  to  be  rapid,  however,  no  reliable  measurements  can
discussed above, in the hydrology and reservoir operation sections.
•
Phot t0 inn;,!??,n l?*s assessment A sediment measurement campaign should be undertaken,
dy, sediment accumulation in the
The reservoir may interrupt fish nugratio ,
■
nC
but this has not been directly hatchery should be
the course of this or previous studies. A fish ladder and
River Ba,>n Integrated Deveioptn.nt Master Plan______ __________ ____
prefeasibility studies
v< s
lung’s shallow, extensive reservoir will favour shoreline growths that provide the h
for mosquitoes, mites, midges, and other insect carriers of disease Fast canal
provide favourable breeding habitat for the fly earner of Onchocerciasis. The pote • 
from the project needs to be studied extensively at the feasibility level
The risk of malaria and other diseases related to mosquitoes, gnats, midges, and earners that breed or depend upon water (yellow fever, dengue, Onchocerciasis 
from being seasonal to becoming perennial The increase will result from improv^u^ habitai offered by the reservoir and its shoreline vegetation Some of the risks associ ■ these diseases can be reduced by controlling wetland vegetation, possibly by recess/''1'"'
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 s 
f( *
chemoprophylaxis is at best suitable only for short-term, non-immune visitors to the protect
The development of immunity and treatment of the population living near the reservoir **
now, an admittedly partial solution
The literature associates rivers with outbreaks of trypanosomiasis, but information about th disease is fragmentary and inconsistent Selkhozpromexport (1988) reported an unconfirmed4$t cases of trypanosomiasis in the upper Gilo River, but this is believed to be adjacent tc lowlands The Gambela hospital reported 1 case in 1981 and 7 cases in 1985. Feasibility stua will need to gather information on the frequency of this disease in the proximity of the ste
Selkhozpromexport (1988) reported the absence of the mosquito carriers of Leishmaniasis m ct lower basin There is no information about their continued absence
The fly associated with Onchocerciasis prefers fast, shaded streams for its egg laying, wd u; make use of canals where these become overgrown with vegetation The removal of vegetacr either side of canals is one obvious control, the use of pesticides another, thought these posed® own set of risks and costs
The snail carrier of Schistosomiasis is reportedly absent from the Alwero (Selkhozpromexport, 1988), it is also absent from the Baro Different alternatives are P055' 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 waler,
(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. ln  P problems arriving, if any. at the existing irrigation project in the Gambela plain, i e at1 reserv oir, should be studied and used in the elaboration of the environmental impact ass
Co^/?/cr/>rg djemowA/or water Provisional minimal continuous releases 1
* equi^
r
3
computed at 8 percent of mean annual discharge or 31 m /s. Feasibility studies wi ® to evaluate the effectiveness of this discharge to sustain present populattons of
and competing water users The present study has not been provided with suffic
---------------------------- ----------------------------------------------------------——
TAMS-ULG Ba ro-A kobo River Basic Integrated Develop incut Master Plan
78
toI ^feasibility studies
.^put' » fo* duration curve based on m
^ments are usually estimated
information about water rights downstrr. onstream users will be affected ACce„ ,
mean daily discfj
V °U’?Vt£ 
v
*^§e,
Of Jt^g ha. k.
flow
jnUed into non-leaky aquifers offer an„tt. ° ^naJ *atrr ■ °W r, ■
f
* o,hff r'^« •* -
The man c 
Show there is no pressure on landfa^ P°puI^On e>._
‘ n area
>n Nippon c .
■“y hr
'*^5 fo??;.Weils
^'^/ty Project
79PRE FEASIBILITY STUDIES
APPENDICES
TAMS-ULG Baro-Akobo River Basin
Integrated Development Matter Plan
AppendicesAPPENDIX 2-1
GEBA HYDROELECTRIC PROJECT Detailed Cost EstimatesGEBA hydroelectric project PREFEASIBILITY STUDY
COST ESTIMATE
Max- Re*- Lev**- 2.170 Dam Type: Earthflfl Capacity: 112 MW A 72 MW
TAMS ContuRanti, Inc.
0C4>K4f
Cog Unrrt:            JjrvM
Amount
Local Foreign Total
crviLWORKS
IoaMS AND APPURTENANT WORKS
0
0
POWERPC7 N0’1
DIVERSION WATERWAYS No.1
0
0
»
POWER PLANT No 2
DIVERSION WATERWAYS No.2
7,085.981
1,155,196
1.907,581
931,915
3.038,645
35,429,903
5,775,978 9.537,807 4,859,577
15.193.227
t QTAL civil Works
14,119,298
56,477,194
70,596,492
0
.0
.0
.»
0
0
0: ELECTRO-MECHANICAL EQUIPMENT IoaMS AND APPURTENANT WORKS
POWER PLANT No 1
DIVERSION WATERWAYS No.1
[POWER PLANT No.2
DIVERSION WATERWAYS No 2
(TRANSMISSION LINES
TOTAL EQUIPMENT
16,075,169
104,812,578
120,887,747
TOTAL BASIC COST
30,194,468
161,289,771
191,484,229
Physical Contingencies
20%
6,038,894
32,257,954
38,296,848
Engineering and Administration
10%
3,623,336
19,354,773
22,978,109
TOTAL CONSTRUCTION COST
39,856,698
212,902,498 j
252,759,196BAROAK   OBO   PROJECT Integrated Mastx Plan
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE Mu. Res. Level: El. 2.170 Dem Type:
Inrt. Capacity: 112 MW & 72 MW
EMthfill
DESCRIPTION
A: CIVIL WORKS
DAMS AND APPURTENANT WORKS
Preliminaries
Access Roads
Diversion Tunnel
Cofferdam
Embankment Dam Spillway (separate from dam) Low-level Outlet
POWERPLANT No.1 Preliminaries
Access Roads
Power Intake
Penstock (surface) Powerhouse (surface)
Tailrace Channel
Switchyard
DIVERSION WATERWAYS No.1
Preliminaries
Access Roads
Diversion Intake
Diversion Canal
POWER PLANT No.2 Preliminaries
Access Roads
Power Intake
Penstock (surface) Powerhouse (surface)
Tailrace Channel
| Switchyard
DIVERSION WATERWAYS No.2
Preliminaries
Access Roads Diversion Intake Diversion Canal
Local
TOTAL 1.0
TOTAL 2.0
<251.588
<562.892
<220,322
581.076
1 0.722.192
6.846.452
159.401
7,085,981 28,343.923
173.279
85,421
126,252
216,479
487,239
0
66.525
1,155.196 4,620.783
286.134
15,819
186,930
1.418,679
1,144.537
63.275
747,719
5.674,715
TOTAL 3.0
TOTAL 4.0
1.907,561
139,787
17,401
126,252
120,631
453,004
0
74.841
931.915
455.797
39,547
186.930
2.356.372
559,149
69.602
505.006
482.524
1,812.016
0
299.364
3,727.
1,823.187
158.187
747.719
9.425.488
TOTAL 5.0geba hydroelectric project
PREFEASIBILITY STUDY
r4MS ConfuKimt, me
K-Ok-K
Max. Ltvtl; El. 2.170 Dam Typa:                      EariftfU
COST ESTIMATE
InitCapAdty: 117 MW 4 71 MW
Coil LjvM:           Jan
A mourn
Local Forergn Total
^ 2^ £Ci^NiCALE°U '
£5
| ,MENT
IL-
.0   ■50®^
1
1
TOTAL 1,0
10,000
12,000
260.800
232,800
21.600
820.040
296.000
1.180000
1.344,000
25.000
151.200
534,400
280,000
483,600
513.534
40,000
48,000
1,043.200
1,131,200
50,000
60,000
1,304.000
J^r intake Gates
pension
'^etVaYes          re              Auxi|jary               Equipment gSors and Generator Auxiliary £q .prnent
U
SSvEiW        Mechanical        Equipment ^liMi Auxiliary Elecirical Equrpment
Main Transformers
Swildiyard Equipment
Unmusuffld Items
1,41000
106.000
4.100,200
2.960,000
11,800.000
13.440,000
250 000
1.512.000
5.344.000
2.800,000
4.836.000
4 JI 5.020
TOTAL 2 0
S,649,424
46,215.796
51.865.220
DIVERSION WATERWAYS No.1
Drvers»cn Intake Gates
21,600
86/00
TOTAL 3.0
21,600
86.400
108,000
POWER PLANT No.2
Power Inlake Gates
Penslock
21,600
361,114
86.400 1.444.456
Intel Valves
1,836.000
I
Turbines, Governors and Turbine Equipment
204.000
963.000
B,667.000
generators and Generator Auxiliary Equipment
915.000
25.000
108.000
322,000
185.000
348,600
345,431
8,235,000
Pmrbouse Crane
$^*0° Auxiliary Mechanical Equipment
225.000
972,000
“Xi7Jea"“'E'wrnM
2.898,000
Equipment
^"wasured Items
1.674,000
3.137.400
2.917,526
35.892,527
TOTAL 4.0
3,799,745
32,992,782
”S^n^“TERWAV3 N°-2
21.600
06,400
103,000
21.600
86.400
108,000
i
TOTAL 5.0
525,000
Hne from pp *110 p- ?• *2
5,775.000
2.100,000 23,100,000
2.625,000
28,875,000
bn e from P.P. #1 to Gilgel Gibe
TOTAL 6.0
6.300.000
31,500.000TAMS ConsutUrH*. Inc.
baro^owpro^ct mv—*—«•"
GEBA hydr0E|_ECTRIC PROJECT PREFEASIBILITY study
COST ESTIMATE
A: CIVIL WORKS
1.0       DAMS AND APPURTENANT WORKS
1.1          PreUmjnarlaa______________________________ 1.1.1      iMobAzatkrn
%
ha
1500
2.259 52
“|               15 00 000
1500
“I         2.259 82
0
1,062 897
0
4.251.588 0
i .i t 113
1J
5 314 485
0
n
Sfle clearance
______
Subfolal
Acc— Roads
ha
1.694 67
6779 46
6 474 33
0
12
0
1.062.897
94 912
I0 4,251.588
379 650
5,314.485
474 562 1
1 2.1
12 2
Road Improvement
km
km
7,909 37 17 400 61
69.602 46
87 003 07
17
295.810
1.183 242
1 479.052 1
1 2.3
Stream Crossing
No
22596 20
90 392 80
112.991 00
0
0
0
°J
Subtotal
390.723                 1,562,892                  1.953.614
1.3
Diversion Tunnel
1.31
Portal excavation
cum
1 36
542
6 78
5.000
8,780
27 120
33.900
132
T unnel excavation
cum
1017
40 68
50 05
21.237
215 960
863.921
1.079 901
1 3.3
Tunnd support - lock boks
T
1.355 69
5 423 57
6 779 46
53
71.591
286 364
357,955
134
Tunnel support - shotcrete
sq m
5 65
22 60
28 25
1 602
9 051
36 205
45 257
135
Tunnel support - arches and ribs
T
451 96
1.607 86
2 259 82
5
136
2,260
9.039
11.299
Concrete lining
cu m
40 66
162 70
203 30
137
Structural concrete
5 781
235 148
SMO 592
1 175 740
cu m
13a 1 39 1 310
3 11
25 99
Formwork
103 95
129 94
800
20 790
83 162
.
103 952 |
sq m
T
m
10 17
246 58
15 82
40 63
994 32
63 27
_______ 50 85 1 242 90
79 09
13 200
751
4 280
,
134,244
186.684
67 385
536 976 ,
74/ 734 / 269 539 /
671,220 1
933 418 / -T.VJ Q21 /
|l 3 12
T
%
11299
500
451 97
500
Subtotal
564 96 _
5 00
486
54 925
50,242 /
1.055.000
219.702 /
200 PM /
4.220,322
274 627 /
251,210 /
5.275.402GEBA HYDROELECTRIC F’fT.OJ&CiX
PRE FEASIBILITY STUDY
COST ESTIMATE
ve
Unit Prices
DwnTyp*:
Lo.        loESCRfPTfOH
I Unlit !
Local
USI
Foreign
USS
I
Total I
USS |c
Local I
UBS \
Cort
Foreign        \ US I           \
Total \ USS \
A: CIVIL WORKS
1.4
Cofferdam
/T 4 1
FoundMion excavation - Common
cum
072
2 .90 |                 3.62
16 075 |                 12.218 I
48.870 i
81.068 \
Mr-
Foundalton excavalion Rock
cum
1 01
723
904
0'
0
----------oj
----------- -------- 2J
143
Sorrow excavation • Earth
cum
066
271
3 39
W2.O0
69,427
277 709 1               347 136 J
1 4.4
Sorrow excavelion ■ Rock
cum
006
384
480
4.500
4320
17,280
21 600
145
Hauling Wl maler lai over 2 km}
cunVkm
010
0.41
0.51
0
0
0
0
146
Unprocessed Ml (piactmaflj
cu.m
045
KB1
2 26
102,400
46,285
ias ij9
231,4241
1.4.7
Processed AN (placement)
cu.m
1.36
542
6.78
4,500
6,102
24 409
30 510
1.4 0
Unmeasured Mams
%
500
500
5.00
6918
27 670
34 588 |
Subtotal
145.260
581.076
726.345
1J
Embankment Ham
15 1
Foundation excavation - Common
cu m
0 72
ZOO
3.62
327,000
238,748
946,992
1 183740
1 5.2
Poundal ion excavation - Rock
aim
1 61
7.23
9.04
16 000
28,928
115 712
144 640
153
Borrow excavation - Earth
cu m
0 69
271
3 39
150 800
102,107
408,427
510 534
1.5.4
Borrow excavation - Rock
cu m
0 96
304
4 00
0
0
0
0
1 55         Heutog AM material lover 2 km)
cum/km
010
041
0 51
0
0
0
0
1.5 6
Impervious core
cu m
226
9.04
11,30
637.500
1 440 750
5 763,000
7.203 750
11.5 7
UhpioceBsed HI (placement)
cum
0 45
1 01
2 20
642 600
290 455
1 161 021
,
1 452 276 I
,
|1 5.6
Processed fill (piecemeal)
turn
1 36
542
6 78
0
0
0
150
Fillers
cu m
339
13 56
1695
84,100
28SO99
1 140 396
1 425 495
°i
1 5.10
Drahis, Iranattona
cum
3 30
.
13 56
1595
0
0
0
0
1.5.11
Rip rap ( placofTwnl)
cu m
1.13
452
565
19.900
22 467
09,948
1.5.12
Drilling for grouting and drains
m
112 435
11 30
45 20
56 50
5.200
58 760
235 040
1 5 13      Grouting
293 flOO
T
112 M
451 97
584 96
775
67 569
1 5 14      Unmeasurod Mams
%
350 275
437 844
500
500
500
127 845
510581
638 228BARO AKOBO PROJECT
Integrated Master Plan
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
TAMS ConeuHanta. Inc.
M-Oec-M
COST ESTIMATE
Mai. Rh L«vM: EL ».1N                        Dam Type
In at. Capacity;
Earthflll
112 MW A 73
MW                            Cost L«v«l:            Jan-M
Item
No.
Unite
Local
USS
Unit Prices
Foreign
USS
Totel
USS
Quantities
Local
USS
Foreign
USS
Total
USS
DESCRIPTION
A: CIVIL WORKS
1.S
161
162
Spillway (separate from dam) BiXk excavation - Common BiJk excavation - Rock
cum
cu m
072
1 81
2.90~
723
l                3 62 9 04
288 000
178 000
208.512
321.824
834 048
1.287 296
1 042 560
1 609 120
1 63
Structural excavation - Rock
cu m
4 52
1808
22 60
0
0
0
0
1 64
Mass concrete
cu m
1808
72 31
90 39
9 400
169 933
679,733
849,666
1 65
Structural concrete
cu m
25 99
103 95
129 94
13,800
358 634
1 434,538
1 793,172
1 66
Form work
sqm
1017
40 68
50 85
6.200
63 054
252,216
315,270
1 67
Steel reinforcement
T
248 58
994 32
1,242 90
1.015
252 309
1,009.235
1.261 544
1 65
Doling for drains
m
11 30
45 20
56 50
7950
89 835
359.340
449.175
1 69
Drilling for grouting and drains/Oom qM )
m
15 82
63 27
79 09
250
3954
15.818
19 773
1 6 10
Anchors (including DriHmg and Groutng)
T
2 962 96
11.931 85
14 914 81
53
158 097
632 388
790,485
1 6.11
Grouting
T
11299
451 97
564 96
35
3.955
16819
19 774
1 e 12
Unmeasured Hems
%
500
5 00
500
81,505
326 022
407 527
Subtotal
1.711.613              6.646.452               8.558.064
1.7
171
17 2
17 3
17 4
17 5
17 6_
177
77T
1?9
17 10
Low-level Outlet____________
Port el excavation___________
Tunnel excavation__________
Shaft excavation___________
Tunnel support ■ rock bolts
!Tunnel support -shotcrete
Tunnel support - arches end ribs
i Lining concrete
1        Structural        conciete
1 36
1017
1808
1.355 89
5 65
451 96
40 68
25 99
5 42
40 68
72 31
6 78
50 85
90 39
6,779 46
28 25
2.259 82
20J 38
129.94
SO 85
0
0
0
0
0
0
Hfoorrmnwwworxkk_________                                                                                         10 17
\ SStteeeell rievtlnnlloorrcceemrnesntni
24B58                 904 32               5 242 90
A 7 .5 5 \Offl>nq lor
tv<1 drmnw
is a?
|4
_
tWj
!
\\ .7 >2 \otoUttna
12
•—
• X. j
\A f XI
n*rr.«
r* cmj fGEBA HYDRO ELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Max. R«i. L«vH: ei 3,i?e
Dim Type:        EartnfM
Inal. CapacRy; 111 MW & 71 MW
Coil Level-, Jan-X
Unit Prien
/ffim
/iva. /descript/oim
UnHa
Local
US 1
Foreign
US J
Tom
us |
Local         1 Foreign \                     Total          \
QuantkUea
US t
J hi*                         * 1
us
A: CIVIL WORKS
2.0 POWER PLANT No. 1
XT            PrrNrnlruriBR
I21.1
MoMtalkwi
LS
15.00
15.00
15 00
173279 1                     693,117 1             866 397 |
121 2
Land Bcqulslton
ha
2,259 02
0.00
2.259 62
0
0L
|2-1.3        1
Sil* clearance
ha
1 694 67
6,779 46
6474 33
0
01
01
Subtotal
173,279
693.117
866.397
2J             Acceit Roads
221
Road Improvement
km
7.909.3?
31 637.46
39 546 65
2
15,619
63.275
79 094
22 2
Now Road
km
17 400 61
69.602 46
87,003 0?
4
69 602
278410
340 0)2
2 2.3
Stream Crossing
No
22 596.20
90,392 80
112 991 00
0
0
0
0
Subtotal
BS.421
341,665
427.100
X3             Power Intake
2.3 1
E nth axcavalkon
cu m
0 72
2 90
362
300
217
369
1.0G6
2 32
Rock excavation
cum
1B1
723
904
0
0
0
0
2 33
Lining concrete
cu.m
40 88
162 70
203 36
0
0
0
0
234
Structural concrete
cu m
25 99
103 95
129 94
1,350
35.OB4
140,335
175,419
2.3.5
Formwork
sq m
1017
40 68
50.65
4 050
41 109
164 754
205 9-0
230
Steal itintorcarrwnk
T
246 SB
994 32
1242 EK)
176
43 750
175.000
216,750
2 37
Unmeaaured rtems
*
500
500
5 0Q
5,012
24 048
30 060
Subtotal
126 252
505.006
631.258
2,4            Penaloe k [turfite)
24 1
Common excavation
cu.m
0 72
2 90
3 62
4.200
3D41
12,163
15204
242
R ock excavillon
cu m
161
723
9.04
1.223
2211
B.845
IT 056
243
Anchor bofli
m
1356
54 23
67.79
0
0
0
0
24 4
Mats concrete
cum
1608
72 31
90 39
2,446
44 219 1
176 875
221.094
2 45
Structural concrete
cu m
25 99
103 95
129 94
0
0
6
0
24 6
Fcrrnwxk
•q m
10 17
<68
50 85
8,967
91,30*
365 591
458 9*9 |
247
Slaat teintorcemenl
T
246 sa
994 32
1,242 90
225
55 931
223 722
276 653
24 B
UnmeaBixed Ulema
%
1000
1000
1000
19680
70 720
98.400
Subtotal
216,479
865.919             t.062,395BARO-AKO8O PROJECT
Inlegrated Master plan
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
TAMS Consultants, Inc.
Qt-Oec->S
COST ESTIMATE
M». R.» L.v^: EL 2,170
D.m Typ«:         E.rtbM
Inal. Capacity: 112 MW A 72 MW
Cost Level:            Jan-M
Unit Prices
Amount
Mem
No
DESCRIPTION
Unite
Local
US 1
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign
USS
Total
USS
2.6
A: CIVIL WORKS
Powerhouse (surface)
251
Common excavalbon
cu.m
072
2.90
3 62
11,340
8210
32,841
41 051
252
Rock excavation
cu.m
1 61
723
904
14.200
25.674
102 694
128.366
2.5.3
Earthfll
cum
045
1.81
226
4.030
1 822
7.286
9.108
2.5.4
Mass concrete
cu m
1606
72 31
90 39
2.258
40 620
163 280
204 101
255
Structural concrete
cu m
25 99
103 95
129 94
2.872
74.630
296 550
373.188
256
Formwork
sqm
10 17
40 60
50.85
6.501
66 115
264.461
330.576
257
Sleel reinforcemanl
T
240 56
994 32
1.242 90
506
125,761
503.126
628 907
256
Roofing
sqm
160 79
723.14
903 93
323
58.394
233.576
291.969
25 9
Btockwork
sqm
904
36.16
45 20
900
8,136
32 544
40 680
2510
Miscellaneous Metalwork
T
72314
2.69257
3,61571
40
28 926
115.703
144 628
2511
Slope Protection
sq.m
452
1806
22 60
980
4 430
17718
22.148
2512
Unmeasured Mams
%
1000
1000
1000
44 294
177.176
221 472
Subtotal
487.239              1.948.957              2.436.196
2.8
Tailrace Channel
1261        1 Common excavation
cu m
072
290
3 62
0
0
0
0
2 62        1 Rock excavation
cu m
1.81
723
9 04
0
0
0
1263       | Unmeasured Mams
0
%
500
500
500
0
0
0
Subtotal
2.7
0
0
Switchyard
0
271
.2 7 2
Common excavation
| Rock excavation
072
181
290
723
3 62
9 04
1 fl. 000
0
13 032
U 7 3 IFo
undattons and dude
124 29
497 16
621 45
240
---------- U
29,830 I
\2 7 4 \Surtacing                                                                                                                1 47
12OQO
\2 7 5       \ Unmeasured asms
1000
5 07
1QOO
7 34
10 oo
17 010 /
Q-Ui /GEBA HYDROELECTRIC PROJECT
PREFEASIBIUITY STUDY
COST ESTIMATE
Ma*. Rrt. Level; 6L 1,171
Dam Typat Earthim
_____________________________________lnj1.   Cag.achy:   ttl   MW   1T1   MW
Cori   LavaL   Jan-M
Il UnlnlDitrLPrr.f._c_a_a____-_-_-__-_-__-_-_-__-_-___'_-_-__-_-_-__-_-__-_-_I1----------     fcrawll
\
/ftam        /
(No. /oeSCR/PTIOW
Local         I Fortin \
TOIM         A
Unit!
Local
UM
Fgrebgn
UM
Total
US 1
Quanl 11 kaa [        US *
J iiii!                        ^U5*1
_____
3 1.1
A: CIVIL WORKS
3.0 DIVERSION WATERWAYS No. 1 3,1         _ Prellnrirwte*
r
MrtlNutto
L.S
15.00
15.00
1500
266 134
1,144.637
1 430,671
3.1.2
Land acquurflm
ha
2.259.62
ooo
2.259 62
0
0
a
o
3 1.3
Site dear«nca
ha
1.694.67
6.779 46
6.47433
c
□
0
9J
Subtotal
216.134              1,144.537               1 430671
3 J Accan Road*
3.2.1
Road Improvement
km
7.908.37
31 637 46
39,546.65
2
15.S19
63 275
79 094
3.2.4
Maw R oad
km
17.4J0.B1
69.602.46
87,003.07
0
0
0
0
32 5
I StJMITl CroiSEDti
No.
22.596.20
90 392 60
112 991 00
0
0
0i
0
Subtotal
15.019
03.275
79,094
3.3             Diversion Intake
33.1
Earth wc a vat Ion
cu m
0.72
2.90
362
1,575
1,140
4 561
5 702 |
3.3.2
Rock exuvaiton
tu m
1.61
723
904
1,275 |
2,305
9 221
11.526
333
Matt ccncretB
cu.m
1606
72 31
90 39
2 550
46.099
164.396
230.495
33.4
Strudmal concreia
l cu.m
25.99
103 95
12994
1350
35 064
140 335
175.419
33.5
Fotrnwork
sq m
10.17
40 66
50 65
•t 662
49,650
196.600
246 250
3.3 6
Steel rcriForGernanI
T
246.56
994 32
1,242 90
ITfi
43,750 |
175.000
2IB75O
3.3.7
UnmeoBured llnrrw
*
500
500
500
6.901
35 006
44 507 |
Subtotal
L86.B3O                 747,719
934,646BARO-AKOTO PROJECT Integrated Master PUn
TAMS Consultants, Inc.
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Max. Res. Level: El. 2,17t
Dam Type:        EarthfHI
Inst. Capacity; 112 MW A 72 MW
Unit Prices
Cort Level: JanA6
Amount
•tern
Mo.
DESCRIPTION
Units
Local
USS
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
M Diversion Canal
341
Common excavation
cum
072
2 90
362
52850
38.263
153 054
191.317
34 2
Rock excavation
cu m
1.81
7 23
9 04
455 000
822 640
3,290.560
4.113,200
34 3
Earth M from borrow
cu.m
1 36
542
6 78
0
0
0
0
3.4.4
Hauling All material
cum/km
010
0 41
051
0
0
0
0
3,4.5
Earth fdi
cu.m
045
1.81
226
0
0
0
0
3.4.6
Lkrxng concrete
cu m
33 90
13S.59
169 49
11,235
380 044
1 523 376
1 904.220
347
Structural concrete
cu m
25 99
103 95
129 94
0
0
0
0
34 8
Formwork
sqm
1017
40 68
50 05
0
0
0
3 49
0
Steel reinforcement
T
248 58
994 32
1.242 90
440
34.10
109 375
437 501
Unmeasured items
546 876
%
500
500
500
67 556
270,225
J37.781
1,418.679              5,674.715               7.093.394*'fvjFraf Maaf^r
GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Mai. Ha. Caval; El. UN
D«nTypt. EartMMI
Inti. Capacity. 112 MW&T2 MW
CMl Laval-.             J an >94
UrU! Prices;
1                                  Amount
\
Units
Local
USS
Foreign
USS
Tolal
Local         1 \
Total        \
usi          Quanta** |               USS
A: CIVIL WORKS
4.0 POWER PLANT No.2
4.1 Prellrrtnutei
J Ms*                Ml \
prr-
MoblNzaton
LS
1500
15 00
15 00
139.7B7 1              559.U9 '1              698,937 1
p.1.2
Land acquisition
ha
2.259 92
000
2 259 82
0
0
0| —
14.1.3
Slle clearance
ha
1 694 67
6779 46
6 474 33
0
0
01
Subtotal
139,767
559.149
690,937
4.2          Access Roeds
421
Road trnprovemenl
km
7,909.37
3l.637.4B
39,546 65
0
0
0
0
422
New Road
km
17,400 61
69 602.46
67 003 0?
1
17 401
69.602
B7OO3
,4.2.3
Stream Crossing
No
22.596 20
90.392 00
112991 00
0
0
0
0i
Sublolal
17.401
89.602
87.003
42              Power ktlake
4.3 1
Earth excavation
cu m
a 72
2.90
3 62
3UO
217
869
1 086
432
Rock excavation
cu m
1.51
7 23
9.04
0
0
0
0
43 3
Lining concrale
cu m
40 60
182 70
203 38
0
0
0
0
43 4
Shuclurel concrete
cum
25 99
103 95
12994
1.350
35 084
140 335
175 419
4 35
Formwork
tq m
10.17
40.58
50.85
4.D50
41.189
164.754
205 943
4 36
Steal leirdtMcemant
T
248 58
994 32
1 242 90
176
43 750
175,000
218.750
437
Unmeasured rtema
u
500
500
SOO
6.012
24,048
30,060
SubtoLal
126,252
505.006
631,256
4 4             Pentlock (surteca|
Common eicHvattan
,
4.4 1
cu m
0.72
2 90
3.62
2,400
1,738
6 950
8 688
442
Rock excavation
cu.m
1 Bl
723
904
640
l l57
r
402B
5.786
443
Anchor txWii
m
13.56
S423
67.79
0
0
0
0
44 4
Mau concrete
cu.m
IBM
72 31
90 39
1.290
23,140
92 550
115,699
4 45
Structural concrete
cu.m
2599
103 95
129 94
0
0
0
0
446
•q m
10.17
40 66
50 85
S.119
52.060
200,241 |
260 301
4.4 7
4.48
Steel relnforcamenl
Unmeasured llem»
T
%
248,50
1000
9M 32
10 00
1.242 90
1000
127
SuMoUl
31.5/C
10l9M 120 631
120.279
43 a&6
482.524
167 848
54,932
603 154BARO-AKO0O   PROJECT Inlegrated Mailer Plan
TAMS Coneull an1a« Inc.
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Mas. Rat. Lnvtl: EL 2.170
Dam Type:
frtri. Capacity:
Earthflll
112 MW 6 7 2 MW
Coat Level:            Jan<M
Unii Prices
hem
No.
DESCRIPTION
Units
Local
US t
Foreign
US 8
Total
US 1
OtianlMlaa
Local
us s
Foreign
US 5
______________ Total
yi>I
44
A: CIVIL WORKS
PowerfiouM (surface)
4.5.1
Common orcir.-aUori
cu m
0.72
290
3.62
10800
7819
31,277
3Q096
45 2
Rock excavHtkxi
cu m
1 51
7 23
904
11.690
21.136
84 542
105.678
453
Earth Hi
cu.m
045
1.81
226
3645
1 646
6590
8.238
4 54
Mass concrete
cu m
ieoe
72 31
90 39
2 345
42/393
169.572
211 965
4.5 5
Structural concrete
cum
25 99
103.95
129 94
2.717
70 609
282,438
353 047
45 6
Formwork
sq.m
10.17
40.68
50 85
6.338
84 457
257.830
322.287
457
Steel reinforcement
T
240 58
994.32
1 242 90
489 |
121.556
486.222
607 778 .
45.6
Roofing
sq m
180 79
723.14
903 93
325
58,755
235022
293,777
4 50
Btoctawrk
tq.m
9 04
36 16
45 20
729
6,590
26 361
32.951
4 5.10
Miscellaneous Metalwork
T
723 14
2 69257
3.615 71
16
13.017
52066
65 083
4.511
Stope Protection
sq m
4 52
10 06
22.50
650
3.842
15368
19,210
4.5.12
Unmet lured items
%
1000
1000
10 00
41,182
164.729
205,911 |
Subtotal
F .612,016
2.265020
Tattract Channel
46,t        1 Common tKcavalton
cu m
□ 72
2 90
3 62
0
0
4 62       |RocK excavation
cu m
1 81
723
9 04
0
0
-------- FT~         0/
01                        0 /
(463         (Unmeasured Items
%
500
500
500
I
J
ol           z
\4.13         (Common tML^aUon
cu.m
0.72
290
u.u         \Rock *nejw«itjn
cum
3 52 I           20 250 f                  14.001 /                  58 644 /                73.305 7
Un      \ r ’■iiftii&n* ■wi
1 01
7.23
904 I
0 f  —                0/
0/
0/
L«irn
124 29
4S7 jg .
■r.irujj
621 45 I                  270 f
j j, &ss 1
134 233 /                  f ffZ                  /
,
t'Ji-LL
1 *7
a a/
------------                               13900 J
/
Tpm /                ■SWtWel /GEBA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Dem Type:
Unit Prices                                 1
fUi'ounl
Unite
Local
USI
Foreign
USI
Total
Local         t Foreign
USI         ^Quantities \             US I          1        USI
A: CML WORKS
5.0 DIVERSION WATERWAYS No.2
1.1 PrrlifTWnTht
5.1 1
MotllMlton
LS
15 00
1500
1500
455,797
1 823,187 |          2,278,984 \
5.1 2
land <kuuisilion
he
2,259 82
000
2 259 82
0
0
0
5.1.3
SHe clearance
ha
1 694 87
6 779 46
6,474 33
0
01
°l                            1 01
Subtotal
455,797              1,823,187             2.276.984
5.2           Access Roads
52 1
Road Improvement
tan
7.909 37
31 637 48
39 546 65
5
39 547
158 187
197.734
522
New Road
tan
1740061
69 602 46
67 003 07
0
0
0
0
5 2.3
Stream Crossing
No.
22 598 20
90 392 80
112 991 00
0
0
0
0
Subtotal
39.547
158,167
197.734
5.3           Diversion Intake
53 1
Earth axcevabon
cum
072
290
362
1.575
1 140
4.561
5 702
5 32
Rock excavation
cu.m
1 61
723
9.04
1.275
2,305
9 221
11,526
53 3
Mate concrete
cum
18 08
72 31
90 39
2.550
46 099
184 396
230 495
5.3.4
Structural concrete
cu.m
25 99
103 95
129 94
1 350
35 084
140 335
T75 419
5.3 5
Formwork
»qm
10 17
40 68
50 85
4 882
49 650
198 600
248 250
536
Steel reinforcement
T
248 58
994 32
1 242 90
176
43 750
175 000
216 750
53 7
Unmeasured Merna
U
500
500
500
8901
35 606
44 507
Sublot al
166,930
747.719
934.648BARo-AKOB0     PROJECT 'nKa^.d Mactef Ptan
TAMS Consultant*. Inc.
GEBA HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Max. flea. Lawk El. 1,170
Dam Type:
Inst. Capacity;
EMlhRM
111 MW <71 MW
Coat Laval:          Jan-85
UnM Price*
Amount
1
Hem
No.
description
Unka
Local
UM
Foreign
USS
Total
USS
Quanlitiea
Locel
us>
Foreign
USS
Total
USS
A: CIVIL WORKS
84
Diversion Canal
54 1
Common ejicavatkn
cu m
0 72
200
362
98.600
59 938
279 754
349,692
5.4.2
Rock «Mca vallon
cum
i.ai
723
904
040,000
1,516,720
6,074.880
7 593,600
5 4,3
Earth nifrom borrow
cu.m
1.36
542
fl 76
0
0
0
0
544
Hauling rm malarial
cm nV km
0,10
041
051
0
0
0
0
S45
Earth r«1
cu.m
0.45
1.61
226
0
0
0
0
546
lining concrete
cu.m
24 86
9943
124.29
1B.54O
460,867
1,843,469
2,304 337
547
Structural concrale
cu.m
25 99
103 95
129 94 ,
0
0
0
0
548
Formwork
sq.m
10.17 |
40 60
50 85
0
0
0
0
54 9
Steel reinforcement
T
246 58
994 32
1,242 90
783
194,638
778 553
973.101
5410
Unmeasured terns
%
500
500
5.00
112.208
448833
561041 .
Subtotal
2.356,372              9,425.486            11.781860GEQA HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
.VO                      Dam Type:            EartWta
inet. Capacity: HI MW A 72 MW
Coat Liv»L
UfW Prtcet
Ajnounl
\
litem
INo. /description
unlit
Local
USS
Foreign
USS
Total
USS
Local      1 Forttqn                     Total        \
QuanllUaa      1 USS                     USS
J
B: ELECTROMECHANICAL EQU
PM ENT
to             OAMS AMD APPURTENANT WORKS
/n-----
Power supply io the dim
LS,
10.000 00
40.000 00
50.000.00
1
10,000                40.000 |               50,000 I
1
tolake and HtAhnd Galea - Low Lewi OutW
each
3000 00
12,000 00
15 000 00
4
12,000
46,000
60,000 I
Li
High Pressure S4cfe Gales ■ Low Level Outlet
each
65,200.00
260.000 00
326.000 00
4
260 B00
1,043,200
1,304 000 |
Sublofil
1.1JU00              1,414,066
2.0             POWER PLANT No. 1
2.1
Power Intake Galea
each
2400 00
a.eoooo
12000 00
9
21600
66.400
108,000
22
Penalodt
T
494 00
1,976.00
2,470 00
1.660
820. MO
3260,160
4,100,200
23
Inlet Vahnea
each
74 000 00
BOB 000 00
740 000 00
4
296,000
2.664 000
2.960,000
24
Turbines. Gowrnxa and Aur'Hacy Equipment
each
295 000 00
2,655,000 00
2.950,000 00
4
1100 000
10620,000
11,600.000
2.5
Genet Mora and Generator AiaUiary Equipment
wch
330 000 00
3,024.000 00
3.360,000.00
4
1 344 000
12.096POO
13.440 000
2.6
Powerhouse Crane
L.S
25 000 00
225,000 00
250 000 00
1
25 000
225.000
250,000
2.7
Station Auxiliary Ntachartcal Equipment
LS.
151,200,00
1 360,600.00
1,512 000 00
1
151 2Q0
1.360.600
1 512,000
26
Station AutoSacy Elect rice! Equipment
LS
534,400 00
4,609,600 00
5 344 000.00
1
M4 400
4,009,600
5 34-JOOO
29
fotaki Twtifomwt
each
70 000 00
030,000 00
700 000 00
4
260 000
2 520,000
2,000 000
2 10
Switchyard Equipment
LS,
483600 00
4,352,400 00
4 636,000 00
1
463 000
4,352 400
4,636,000
2.11
U nmeaauf ed Kama
U
10
10
10
513,564
4,201.436
4.715.Q2O
Suhtolll
1,440,42*      44,2 fl.701       41.141.220
3,0             DIVERSION WATERWAYS No.1
|31
1 Diversion Intalw Gairt ________________
| tact- |
2,400 00 I 0,600.00 |
12,000 00 |
B I 21 600 r 36,400 I 108,000 |
Subtotal
li,M0
ie.400
100,000BAROAKoeo PROJECT
TAMS ConeuttenU. Inc.
MMtw pi„
GEB A HYD
ROELECTRI
C PROJE
CT
PREF
EASIBILITY
STUDY
COST ESTIMATE
Maa. R...
El. Z.V*
DamTypa:
Barthnil
Mat. Capacity: 1U MW A 72 MW
COM L«vM:
Ihem
Ino ^DESCRIPTION
.
Local
USS
Unh Prices
Foreign
USS
Total
US S
Local
.....                   USS
Foreign
USS
Total
USS |
B:  ELECTROMECHANICAL  EQU
PMENT
4.0              POWER PLANT No.2
41
Power Intake Galea
each
2,400 00
9 600 00
12.000 00
9
21 600
86 400
108.000
42
Penstock
T
494 00
1 976 00
2470 00
731
361 114
1,444.456
1 805,570
4.3
lnia< Valve*
each
68 000 00
612000 00
680 000 00
3
204 000
1,836.000
2,040.000
44
Tixbine* Governor* end Turbine Equfimenf
each
321,000.00
2 889.000 00
3 210 000 00
3
963.000
8.667 000
9 630 000
4.5
Generalora and Generator Auxikary Equipment
each
305.000 00
2.745 000 00
3 050 000 00
3
915000
8 235.000
9.150000
46
Powerhouse Crane
LS.
25 000 00
225.000 00
250 000 00
1
25 000
225000
250 000
47
Slatton AuxiUry Mechanical Equipment
LS.
108,000 00
972.000 00
1 080 000 00
1
108 000
972.000
1 080 000
4,|
Station Auiollary Electrical Equipment
LS.
322 000 00
2 898 000 00
3220 000 00
1
322.000
2.898 000
3.220 000
*£
Main Transformers
each
62.000 00
558 000 00
620 000 00
3
186 000
1 674 000
1 860 000
4 10
Switchyard Equipment
LS
348.600 00
3.137.400 00
3.486.000 00
1
348 600
3.137.400
3.486 000
4 11
Unmeasured Hems
%
10
10
10
345 431
2 917526
3 262 957
Subtotal
3,789,745           32.OT2.7S2          38,992,627
5.0 DIVERSION WATERWAYS No.2
________ __________ ___________ ____________
I51
IKvara^onIntake Gatti
[each |
2,400 00 |             9,600 00 |
12,00000~[
Subtotal
9 1 21,600 |
21,100
66,400 | fOfl.OOO /
IS, 4 00 101,000
u,—
6.0 TRANSMISSION LINES
ISC 230-MV Tr*n* LlnolromP.P S1 lo P P r2
km
35,000 00
140 000 00 1         175,000 00 /
____         \SC 236-kV Trane Un* Horn p p w\ u, GMgel Giba
15 1         525.000 /           2,100.000 /           2 625 000 /
km
35,000 00
140.000 00 1         175.000 00 /
,,
165 / 5.775.000 / 23,100,000 / 26.625.000 /
0.300.900
29.200.000
31.900,000DRAWINGS
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
Reservoir Plan
Geba 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. <“V.
Bridge
pow '    erhouse Vp 2
kKvla
FiWwW
>Sj=^.      . and Intake No 2 ~
;;A
Powerhouse No. 1
PROJECT LOCATION MAP
20C 400km
Diversion Dam
.—LI 1 J 
and Intake No. 1
SCALE
-'
ministry of water resources
ADDIS *3 AB a ETHIOPIA
TAMS - ULG
NEW YORK - LCWDON - ADEMS AQABA
BARO-AKO0O MASTER PLAN PREFEAS1BIUTY STUDIES
GEBA H1WOELECTRJC POKR PROJECT
PROJECT PLAN
1
x
Date: Octot r J996                             Dwg No GE - 1
N KILOMETERELEVATION IN METERS
Gebo Reservoir
2^Q| Uox- Lev* n
Normal Mir
Perstock 3.2i
el ia<o
1680
r- Power Carol Q— 5l-7rr3/»
1
a er stock 3.2>
Divert «r 2 Powrrouw
El. 1500
9rio$« on
Metu-9edei« Rocc
20
1
distance in kilometers
MINISTRY of water resources ADC'S A3ABA ET-lCPlA
TAMS - ULG
VORX - -OSODN - ADOS A3ABA
BARO-AK
rgo MASTER PLAN PREFEASIBIUTY STUDIES
hiorooectwc power proxct PROJECT PROFIT
Date: Octo:
|0.,NoCE-2IlHUng Ba i
Sn\
PROFILE on DAE AND SPILLWAY AXIS
(.Intake Tower
PROFILE ON INTAKE AND DIVERSION TUNNEL
(Spillway Crest El. 2170.0
"
------------
Existing Ground Surface
SlopeO.5 %
Slope 40 0 X EL 2130.0 El. 21235
Geba River
Stilling Basfo
PROFILE ON SPILLWAY              CHUTE
ministry of water resources
A DO IS ABABA ETHIOPIA
TAMS - ULG
<¥ YOftX - LONDON - ADO IS ABABA
BARO-AKOBO
MASTER PLAN
PREFEASIBILITY STUDIES.
GEEA HYDROELECTRIC POWER PROJECT
GEBA DAM - PROFILES
:      Oct©b   W*
er
Dwfl No GE - 5I Dam
3.0 Stripping *
Core Trench
ministry of water resources
$H*F T
r U I NT
.longitudinal section throu£]1^—
_______________________ Pols ABABA ETHIOPIA______________________________ TAMS - UL6
______________SEW YO«K • 10*00* - ADDIS AflABA_____________________________ 9AR0-AK0BQ MASTER PLAN PREFEASIBILITY STUDIES
GEBA HYDROELECTRIC POWER PROJECT
□ AM CROSS - SECTION AND POWER OUTLET 0>»t : October ____________________ | 0*9 *»             6€ - 6Dam Crest EL 2T7S.0
C Crest
Spillway Crest El. 2170J
O,
»n i
Grout Curtain
0.075 Drain Holes 5.0
----------------------------------------
SECTION TROUGH SPILLWAY CREST STRUCTURE
STILLING BASIN^H^
ministry of water resources.
_______________________ A00IS ABABA ETHIOPIA_______________________
TAMS - UL6
_________ _______ MtW YORK - LONDON - ADO IS ABABA_____________________ 3ARQ.AKQ90 MASTER PLAN PREFEASIBILITY STUDIES
GEBA HYDROELECTRIC POWER PROJECT SPILLWAY PROFILE AND SECTIONS
D»te : OcttMr
1 Dwg Ne GE - 7
-Bft
SOO WC4 1500                    2000        2500
Hetgrs
Seal* 1              50.000
I
MINISTRY OF WATER RESOURCES
*DO!S ABABA ETHIOPIA
TAMS - ULG
KV TO«K
UOHOOH - ADDIS ABABA
w. $00 Scale 1       50.000
ZOC 2500
|BARO-AKCB0 MASTER PLAN PREFEASIBILITY STUDIES
G = BA HYDROELECTRIC POWER PROJECT POWER DIVERSIONS - PLANS.
I
O( •ober im
\ Dwg No GE - 8Intake
Structure __________________ Spillway
Olvirslor^Slulcevay
ELEVATION
UPSTREAM ELEVATION OF SPILLWAY
AND INTAKE STRUCTURE
Scale 1:1000
Concrete Ogee Spillway
and Roller Bucket
REFLECTED SECTION
Scale 1:200
MINISTRY OF WATER RESOURCES
______________ KOO IS ABAI A ETHIOPIA________________________
TAMS - ULG
_______________________ YOtK - LOMOOM - ADO IS ABABA_________________________________
BARO-AKOBO raster plan PREFEASIBILITY STUDIES
geba hydroelectric power project
POWER DIVERSIONS - INTAKES
PLAN
D»te •- October WH\ 0w9
6€ - 9Existing Ground
Headrace Canal
j-Penstock
Assumed Rock
Surface,
Pcvtrhouse T.V.EL 1840.0 (6rt*River )
GEBA 1 PENSTOCK AND POWERHOUSE PROFILE
Existing Ground
----------------- J
POWER CANAL TYPICAL SECTION IN VERY STEEPLY SLOPING TERRAIN
Jlwflrace Canal
Assumed Rock
I Penstock
Existinjjiround Surface
Powerhouse
TV.  El.  1500.C I feba Riv<r ?
pnWER CANAL TYPICAL SECTION IN LESS STEEPLY SLOPING TERRAIN MINISTRY OF WATER RESOURCES
_______________ __________ ADO IS ABABA CTHlOeiA____________________________________
TAMS - ULG
-^^PE_NSTOCK AND POWERHOUSE PROFILE
______________________<W YOW* - LOMOOM - ADO IS AB*BA______________________________
9AR0-AKQBQ MASTER PLAN PREFEASIBILITY STUDIES^ GEBA HTOROELECTRIC POWER PROJECT
POWER DIVERSIONS - CANAL SECTION ANO PENSTOCKS
Dwg W GE - IQGEBA HYDROELECTRIC POMER PROJECT
POWERHOUSE NO1 - PLAN ANO SECDON
Date: October ’.996
Dwg No GE - H300x10 00
S«rv« Boy
I
I
MINISTRY OF WATER RESOURCES
ADDIS AfiABA ETHIOPIA
TAMS - ULG
MEW YORK - LONDON - ADOS AfiAfiA
BARO-axcbo MASTER PLAN PRSFEAS1BIUTY STUDIES
flEBA HYDROELECTRIC POWER PROJECT POOW5E NO_2 - PLAN AM) SECTIONAPPENDIX 3-1 GUMERO HYDROELECTRIC PROJECT
Detailed Cost EstimatesBARO-4KOBO PROJECT Integrated Matter Plan
GUMERO HYDROELECTRlr "*S.
prefeasibility study0JEct
i
i
^..^'2T.nT,M?TE
lafio Dam Type-
DESCRIPTION
A: CIVIL WORKS
DAMS     AND     APPURTENANT     WORKS
POWER PLANT No.1
DIVERSION      WATERWAYS      No.1
4.356,819 577,281
POWER PLANT No.2
728,329
DIVERSION      WATERWAYS      No.2
621,614
POWER PLANT No.3
548,395
DIVERSION WATERWAYS No 3
717.405
1.484,226
17 '427.274
2.309.123
2.913,316
2.486,457
2.193,581
2.869.621
5.936,906
TOTAL CIVIL WORKS
9,034,069
36J36J7I
B: ELECTRO-MECHANICAL EQUIPMENT
1.0 DAMS AND APPURTENANT WORKS
2.0         POWER PLANT No.1
3.0         DIVERSION      WATERWAYS      No.1
4.0         POWER PLANT No.2
5.0         DIVERSION       WATERWAYS       No.2
6.0         POWER PLANT No.3
7.0         DIVERSION       WATERWAYS       No.3
8.0         TRANSMISSION LINES
52,400
1.374,144
1,600
1,798,559
1,600
1.969,537
1,600
884,520
209,600 5.496,577
6.400
7,194238
5.400
7,878,147
6.400
3,538,080
51
u
IS
c
l!fj
t 4.G!
TOTAL EQUIPMENT
TOTAL BASIC COST
15,118,030
60,472,111
TH
Physical Contingencies
20%
3,023,606
12,094,424
Engineering and Administration
10%
1,814,164
7.256.6M
TOTAL CONSTRUCTION COST
19,955,799TAMS Cwutrti. Inc.
GUMERO hydroelectric project PREFEASIBILITY STUDY
COST ESTIMATE
M*x- R*»- Lev* El 1.110 Dan Type:                       Roefcffl
Inst Capacity: 1UMW. 114MW4 11 MW
______________________________ Com Lewt
Amount
Local Foreign
PURTENANT WORKS
l!
u
u
^litniMries
!Access Roads
Otvttsion Tunnel
Goferdam
RodcfH Dam Sfnowtf (separate from dam)
LwMevet Outlet
853.523
79.094
429.760
194,175
2,322,931
651,141
26,194
2.814,091
316,375
1,719.041
778.701
9.291.726
2,604.563
104,777
3267.614
395.469
2,146.802
970,876
11,614,657
3,255,704
130.972
I’7
TOTALjLO
4.3S6J1S           17,427,274           21,784,093
11 U
i: u
POWER PLANT NO.1
Pnlifriirvaries
Access Roads
Power Intake
M  Penstock (surface) 25 Powerhouse (surface)
U
A?
346,369
501,112
168.714
180.415
831.518
0
180.996
432,961
751.390
210.892
225.519
1,039,397
0
226,245
si n
12 U
-<
Tiiirace Channel
Switchyard
■_______________________________ TOTAL 2.0 AVERSION WATERWAYS NO.1
Frtfiminaries
i: «ss Roads
Intake
Version Canal
TOTAL 3.0
66.592
150,278
42,178
45,104
207,879
0
45,249
577,281
109,249
0
59.563
559,516
728,329
93,242
185.079
42.178
48,397
207.468
0
45,249
621,614
82,269
0
59,563
406,573
543,395
436,997
0
238253
2.238,065
2,913,316
546.247
0
297.817
2,797.581
3,641,945
^intake
^ hann*‘
372.969
740,317
168,714
193.589
829,872
0
180,996
"jim
----------- TOTAL 4.0
Sl’iari
(ts
VVAt^WAYSN^2-----------------------------------------
TOTAL 5.0
329.037
0
238,253
1,626,290
2,193.561
466,211
92S.396
210.892
241,987
1.037.340
0
226,245
3,1M,071
411,296
0
297,817
2,032,863
2,741,976BARC>A>«*o’,ROJtCT
GUMERO HYDROELECTRIC project       1
PREFEASIBILITY STUDY
COST ESTIMATE
Max.R»*-L»ve,:EL 1310 Dam Type:                    fam InsL Capacity: 121MW. 1UMW12fa
’
DESCRIPI122
preliminaries
Access Roads
Power intake
Penstock (surface) Powerhouse (surface)
Tailrace Channel
Switchyard
□NERSioNWATERWftVS no.s
Preliminaries Access Roads Diversion Intake Diversion Canal
Local
107.611
308,465
42,178
48,397
173,501
37.252
168,714
1W.M9
694.008 H
G•
149.007   ,
2.849.tt1 !? 5
222.634          890.538
80,501               322,004 di
1,181.091 4,724.3661 til
4J
0 I|        0 I
------------ [ 1,484,226
5.936909 <CinUbK.
61-Oec-H
GUMERO hydroelectric project PREFEASIBILITY STUDY
COST ESTIMATE
Max. Re*. EL 1,618 Dam Type: RoddUI
Init Capacity: 12.2MW, 1L4MWt 21 MW
CostUvet
Local
Amount
Foreign
;,^g^MECHANICAL EQUIPMENT Appurtenant works
I
I
1
3
0
1
2
3
4
5
6
7
I
Gates - Low Level Outlet
•J^reSl-de Gates - Low Level Outlet
TOTAL 1.0
POWER-PLANT NO.1
Power Intake Gales
Penstock
Intel Valves
Turbines, Governors and Turbine Auxiliary Equipment Generators and Generator Auxiliary Equipment
Powerhouse Crane
Station Auxiliary Mechanical Equipment Station Auxiliary Electrical Equipment
1    Main Transformers 10  S*4chyard Equipment
II    Unmeasured Items
10.000
3,200
39.200
52,400 |
1,600
154.622
44.000
232,000
336.000
45,000
69,000
161.000
76.000
110.000
124.922
40,000
12.800
156.800
209,500 I
6,400
618.466
176,000
928.000
1.344.000
180.000
276.000
724.000
304,000
440.000
499.689
50,000
16.000
196.000
262.000
8.000
773.110
220.000
1,160,000
1,680,000
225.000
345.000
905,000
380.000
550,000
624,611
c
1
------------------------ ----------- --------------------- TOTAL 2.0
1,374,144          5,496,57]r 1      6,870,721 I
DIVERSION WATERWAYS No.1
Version Intake Gates
1.600
6.40C           I 8,000
powerST^---------------------------- total 3.0
1,600                       6,400                    8,000 I
1
2
3
4
5
e
7
I
5
10
’1
PLANT No J
1,600                       6.400                   8.000
168,454                   673.816
842,270
T^VafVC5
Gef*r^on                  and Turt)jne Auxiliary Equipment Cran*neratOr Auxihary Equipment
52.000                208.000                 260.000
294,000 1.176.000
508.000 2,032,000
1.470.000
2,540,000
45.000 i
180.000                225.000
73.000               292.000                 365.000
261,000
112.000
120.000
163,505
1.044,000 I            1,305,000
448.000                 560.000
480,000                600.000
654,022                  817,527
3iv^Sl°NVVATcEn---------------------- TOTAL 4 0
.
1.798.S59 I          7,194,238 1         8,992,797 1
No ’2
1.600
6.400
8,000
TOTAL 5.0
1,600 f
6.400                    8,000 ]GUMERO HYDROELECTRIC PRn lc PREFEASIBILITY STUDY *
COST ESTIMATE Y Level: El. i,«10 Dlfn
Capacity; 12JMW
I
Item
No.
s.o
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
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
1.600
173.888
56,000
334.000
552.000
45.000
75.000
300.000
128.000
125.000
179.049
6.400
695 552
224,000
1.336,000
2208.000
180.000
300.000
1 -200.000
512,000
500.000
716.195
1
1
■j
e
1
11
ji
7.0
7.1
DIVERSION WATERWAYS No.3
Diversion Intake Gates
i ,aoa,bJ7 1.600
7,871,147 6.400
TOTAL 7.0
1.600
6.400
8.0
8.1
8.2
8.3
TRANSMISSION LINES
Transmission Line 132-kV from Gumero No 1 to Gambeia-Gore Transmission Line 132-kV from Gumero No.2 to Gumero No.1 Transmission Line 132-kV from Gumero No.3 to Gumero No.2
294.840
189.540
400.140
1,179,360 758.160
1.600,560
U
1
11
TOTAL 8.0
884,520
3,538 NO
jj<3 "U^Z,EF<C> HYDROeueCTRtC
PREFEASIBILITY study
•v
M “ 
------------------------
COOT E8TIMATB
ei
o.™r„»;
RockRB
Itlgm
l^L              iDESCRfPTfOH
o: ELtU rKU-MbCHANICAL EQUIPMENT
0.0                 POWER PLANT No. 3
r
1
l»Wt. C.p*<«y. 11JMW, 114MW t 11MW
Unit Pik«t
I
I
Local
]         Foreign            |            Total             1
, Local
lom           \
— "**________ ______ !“»________ ______ y» »
u
U 'S »             Iqu-hsi..      ---- 1—“—1 —   — >
hcrwMirtt
\ r~r \
1
/«.1                      / Power intake Gates
each
BOO 00
3,200 00
4000 00
2
1 600
6.2                      I Penstock
T
6 400
8000 \
494 00
1 976 00
2.470 00
352
173 860
695 SS 2
669,440 1
6.3                    | Inlet Valve*
each
28.000.00
112,000 00
140 000 00
2
56.000
224 000
200 000
64
| Turbine* Governors and Turbine AuxNkary Equipment
each
167.000 00
660 000 00
635 000 00
2
334 000
1 338 000
1 670 000
6.5                         Generator* and Generator Auxiliary Equipment
each
278.000 00
1 104,000 00
1 380 000 00
2
552 000
2 200 000
2 760 000
6 6                         Powerhouse Crane
L.S
46 000 00
160,000 00
225 000 00
1
45 000
100 000
225 000
67
Station Auxiliary Mechanical Equipment
Li.
76.000 00
300,000 00
375 000 00
1
75 OOO
300 000
375 000
Slation Auxiliary Electrical Equipment
LS
300.000 00
1,200.000 00
1 500 000 00
1
300 000
1,200 000
1 500 000
60
Main Transformers
each
LS
64.000 00
125,000 00
256 000 00
500 000 00
320 000 00
625 000 00
2
1
126.000
125,000
512000
500 000
5-uiOOO 625 000
244
6 11
Unmeasured Hems__________________ ____ ____________________ -_________ --------------------- - ---------------------------------------------------------------------------- Subtotal
%
10
10
10
179 049
1.*8*,t37
716,105 7,678.147
695, B.V47.M4BARO-AKOBO PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultants. Inc.
01-Dec-W
Max. Res. Level: El. 1,810
Oam Type: Rockfill
Intt. CipicHy: 12.2MW, 11.4MW A 21MW Cost Level:                                                                 J«n46
Unit Prices
Amount
Item
No.
DESCRIPTION
Units
Local
US 8
Foreign
USI
Total
USI
Quantities
Local
USI
Foreign
USI
Total
USI
A: CIVIL WORKS
1.0 DAMS AND APPURTENANT WORKS
1.1 Preliminaries
1.1.1
Mobilization
%
15.00
1500
15.00
653.523
2,614 091
3.267,614
1.1.2
Land acquisition
ha
2.259 82
000
2,259.82
0
0
0
0
1.1.3
Site clearance
ha
1,694.87
6.779.46
8,47433
0
0
0
0
Subtotal
653.523              2,614.091              3,267.614
1.2 Access Roads
1.2.1
Road Improvement
km
7909.37
31.637.48
39 546 85                     10
79.094                 316,375                   395.469 /
1.2.2
New Road
km
17,400.61
69.602 46
87,003 07                      0
!L                       !u
1.2.3
Stream Crossing
No
22,598.20
90.392 80
112.991 00
0
ol                                               ZU
oj
Subtotal
1.3
Diversion Tunnel
I1.3.1        1 Portal excavation
11.32        {Tunnel excavation
11 3 3         \Tunnal support - rock boll a
11 3.4        { Tunnel support - sbolcreie
H35         \t unnet support - arches and riba
SB       \ Conor Ma Hnlng
\> ,37        \a\iuLtuiil concrete
\* -3 ®       \F fMTVW«CMta
cu m
316.375
10 348 1
395.469
13 560 /
cu.m
T
323.406 I 404 256 I
910641 1 138,301 /
sqm
1.36
10 17
1 355 89
565
451 96
40 oe
75 90
IO 17
542                      6.78
40 68                    50 65
5 423 57 6 779 46
22 60                   28 25
1.807 86 I             2.259 82
162 70 I                 203 38
103 95 1                129 CM
79.094
2,712 1
80 852 1
27 660 /
3.896 /
15.594 1
T
cum
2.000 /
7 950 /
20 |
690 /
°
2 450 /
o/
5,500 1
310 /
/
0/ -                      0 1
99,656 / 396.625 1
cu m
•«1 rn
O/
O1
19 493 /
0I
*96261 /
O/
t
40 at I
80 09
88 01*i /
/
223.7*0 /             270 67K /
H
2<n 30
in iu
?a,L
I
MM. M» /
W
------- V-
------ Ltj< mm
z—
I
jrrjM» /
idMiMa f
x ma* 'ti't i jmarr-*. w**.
/GUIWEKO HYDROELECTRIC PROJECT
At^r*,*** Matter
PREFEASIBILITY STUDY
COST ESTIMATE
frfMTl I
|no, /oescriptom________
A.' CIVIL WORKS
1J          Cofferdam
|       UrWtB
Locad
UM
Foreign
US 1
ToW        | US 1       ]<
Cotter.
Anx>um
Foialgn
US t
nrr-
FcHjnda14xn exciwutiDn - Common
cu.m
072
2 90
3 02
28,700
19.331
77 323 |                 96 654
b——-
142
Founcfohbn eKcavallflf - Rock
cum
1.61
7.23
9 04 1
0
0
0
0
143
Borrow airovillfln - Eirih
cu.m
065
271
3 39
13M0G
69 632
355.526
446 156
1.4 4
Borrow tKcavaltan - Rock
cu.m
cue
3 84
460
7.000
6,720
26,eeo
33 600
1.4,5
H *Lrflrtfl flw malar III (cwar 2 km]
cunVkm
0 10
041
0.51
0
0
0
0
1.46
Unproce«B«l fill (placeman!)
cu m
0.45
1.B!
2.26
132.200
59.754
239016
296,772
1.4.7
ProcMiwi fl tplacomehl)
cu.m
1.36
542
67B
7,000
9.492
37 9641
47 460
1A8
Unmeasured Hems
%
500
SOO
5 00
9 246
36.965
46 232
Sublet sJ
104.175
77fl,rm                  970,676
1.1
RocklllH Dam
1.5.1
Foundation arc avaUon - Common
cu m
072
2.90
3 62
221 560
160 424
641,696
602 120
1.52
Foundation sxciM*1ton • Rock
cu.m
1.61
7 23
004
45 sao
62 409
329 635
412 043
115.3
Borrow excavation - Earth
cu m
0M
2.71
339
0
0
0
Q
16 4
Borrow eMcaveUgn - Rock
cu.m
096
354
450
478JOO
456 976
1 635 904
1.5.5
Hauling BU malarial (waf 2 km]
cu m/hm
,
D.1D
0 41
2 294 6BO
0 51
0
0
Q
0
1 55
Imparvlou* core
cu m
2 26
904
11 30
202 390
1.5.7
457.401
Rockfifi (placement}
cu.m
OM
1 629 006
2.71
2 Jfl? 007
3 39
466,330
331 06ft
1.5 8
Fill era
cu m
1 324 351
□ 39
135ft
1 655 439
16.95
21 960
74 444
150
Drotaajranaaion*
cu.m
3 39
297 770
1350
372 272 "i
16 65
1 5.10
135,030
Rip-rap (placer^eMJ
cum
457,752
1 631 007
? 2firt 7^
1.13
452
5 65
25,590
1511
Drying for grouting and dralna
26 017
t JU <rt 1
m
11S 607
11 30
45 20
M 50
5,720
1 512
Growling
64.636
T
256 544
1AA
H2.89
451 07
564W
652
1,513
Unmeasured Merna
96 260
365 077
jai
U
5 00
500
5.00
110,616
442463
553 079
2.322.031BARO-AKOBO      PROJECT Integrated Matter Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultants, Inc.
01-Dec-M
1.610
Inst C
Dam Type:     Rock fill
r. 12.2 MW, 18.4MW A 21 MW
Cost Level:           Jan-81
Untt Prices
Amount
ttem
No.
DESCRIPTION
UnMs
Local
USS
Foreign
USS
Total
USS
Local                  Foreign Quantities              USS                      USS
Total
USS
1.6
A: CIVIL WORKS
Spillway (separate from dam)
1.6.1
Bulk excavation - Common
cu.m
0.72
290
362
180.000
130.320
521,280
651,600
162
Bulk excavation - Rock
cu.m
1.81
723
904
80 400
145 363
581 453
726.816
1.6.3
Structural excavation - Rock
cum
452
18.08
2260
0
0
0
0
1.64
Mass concrete
cu.m
18.06
7231
90 39
12.555
226,969
907,877
1.134 846
1.65
Structural concrete
cu m
25 99
103 95
129 94
510
13.254
53,016
66 269
1 6.6
Formwork
sq.m
10.17
40.68
50.85
7,430
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
1.6.8
Drilling lor drains
m
11.30
45 20
56 50
1.200
13,560
54 240
67,800
1.6 9
Drilling lor grouting and drainsffrom gall.)
m
15.82
63 27
7909
40
533
2.531
3,164
1.6.10
Anchors (including drilling and Grouting)
m
2 982 96
11 931.85
1491481
22
6.563
26,250
32.813
1611
Grouting
T
11299
451 97
564 96
4
452
1.808
2.260
1.612
Unmeasured rtems
%
5 00
500
500
31.007
124.027
155,034
Subtotal
651,141             2,804.563             3.255.704
1.7
Low-Uvel Outlet
h.7.1        ' Portal awcavaiion
cu m
1 36
542
678
oT                 0
0/
0/
H.7.2       Ilunrval excavation
cu m
10 17
40 68
50 85
0I
0                            0I
0I
15.7.3       \ Snaft cxcavUlon
cu m
16 08
7231
90 39
°I
0                            0/                         0I
15 7 4       \I unnat support - foCX bofta
t            ■       1 *         .................-         —     — \Turxnei eupoort ■ ahuAciela
T
1,355 89
5 423 57
8 779 40
01                      0I                        0I                       O1
\5 .7 5
»qm
5 65
22 60
26 25
01
0[                       01
o1
h T A                                   •uppoH - atutwv end
T
461 ®6
1 BO7 BO
2 2Sfl B7
oI                      01
o/                       o/
\1 7 .7             \\
CU m
co nn
107 TO
701 VI
o1
oJ
yt  r •»                    <UI»'.......... \a 1   «» X* •MtTTWwrtil
O/ o7
».• /
r ______ ,41141 .
__ —/ —
___ —
"Jj»V —-----w
—«
*«
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Mul Rh, Level: EL 1.116
Dam Type:        RccilW
Inal. Capacity;     1UMW \B4MW & 21 MW
Coat Level.
Unit Price*
r                                Amount
UnHe
Local
l)S t
Foreign
US I
Total
US >
I        Local        \ Foreign \                      Total         \ QuanUltea |          U&t          \          US 1         \ y*3 A
A: CIVIL WORKS
2.0
POWER PLANT No J
2.1
Prtllirdnartea
2J.1          |Mabltoiton~ 21,2         Land aegtea Ifcn 2.1,3 .SladaanTO
L.S
1100
1500
1500
M592
346 369
432.961
ha
2 259.62
0 00
2.259 62
0
0
0
0
ha
1,694 07
6779.46
6 474 33
0
0
0
0
Subtotal
06,592
346,369
432.961
2.2
Accaaa Roadi
22 1
Road improvement
km
7 909 37
31 63740
39 540.05
61
63.275
253,100
316.375
22 2
New Road
fcm
17 400 81
69 602 4fl
07.003.07
5
07 003
3460)2
435,015
2.2.3
Slioam Crossing
No
22 590 20
5C.392.60
112901.00
0
0
0
0
Subtotal
150.270
601.112
751.390
2J             Power Intake
23 1
Earth Excavation
cu.m
0 72
2-00
3 62 1
110
BO
318
390
2.3.2
Rock tMCtvauori
cu m
1 Bl
7 23
904
0
0
0
0
233
Lining ccixrala
cum
40 66
162.70
2O3.M
□
0
0
0
2.3 4
Structural concrete
cu m
25 99
103D5
120.84
450
11.605
46 7TB
56.473
2.3.5
Formwork
sq.m
10.17
40 60
50.65
1,350
13,730
54916
66 846
1 2.3.8
Sleet lalntercemant
T
246 50
094.32
1,242 90
50
14666
56. MB
73.331
2.3.7
Unmaaamed Merna
%
SOO
500
500
2.006
6 034
10 042
Subtotal
42,170
166,714
210.082
2J             Panalock (surface]
241
Common •xtavwtlofi
cu m
072
2 00
302
2 400
1,730
0060
sun
2.4 2
Rock MMUM
w.m
1.61
7 23
9.04
250
452
1 BOB
2 260
243
Anchor bokt
m
1356
54.23
07.79
0
0
0
0
2.44
Mast concrete
cu m
10,00
7231
00 39
250
4,520
16,070
22 596
2.45
Structural concrete
cu m
25 09
103 95
129 94
250
0407
25 006
32,465
240
Formwork
S2E
ID 17
4006
50 65
2000
20.340
01 300
101 700
2 4.7
Steel r elnkycemenl
T
240 50
094 32
1 242 80
30
7 457
29 530
37.267
24 0
UnmiBturod Mama
U
1000
10 00
1000
4 J 00
16 401
20 502
45,104
1W.415
225.519BARO-AKOBO PROJECT Integrated Matter Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultants, Inc.
01-Dec-44
Max. Res. Level: El. 1,110
Dam Type: Rockfill
12.2MW, 18.4MWA21MW
Unit Prices
Amount
litem
|No. JOESCRIPTION
Units
Local              Foreign USS                   USI
Total
USS
Quantities
Local Foreign Total
USS USS USS
A: CIVIL WORKS
2.6
Powerhouse
2.5.1
Common excavation
cum
0.72
290
362
6300
4,561
18.245
22,806
2.5.2
Rock excavation
cu.m
1.81
7.23
904
4.780
8.642
34.569
43.211
2.5.3
Earthfill
cum
0.45
1.81
226
3.900
1.763
7 051
8,814
2.5.4
Mass concrete
cu.m
18.08
7231
90 39
1.036
18,729
74.915
93.644
25.5
Structural concrete
cu.m
25 99
103 95
129.94
976
25 364
101,457
126821
2 56
Formwork
sq.m
1017
40.68
50 85
2.990
30.408
121.633
152.042
2.5.7
Steel reinforcement
T
246 58
994 32
1.242.90
198
49.219
196.875
246.094
2.5.6
Roofing
sq m
180 79
723 14
903 93
162
29.287
117,149
146 437
259
Blockwork
sq m
904
36 16
45.20
324
2.929
11.716
14.645
2.5.10
Miscellaneous Metalwork
T
723 14
2.892 57
3,61571
25
18.079
72.314
90,393
2511
Slope Protection
sq m
4.52
1808
22 60
0
0
0
0
..
2 5 12
Unmeasured items
%
10.00
10 00
1000
18 898
75 593
94 491
Subtotal
207.879               831,518            1,039.397
21
B. A     \ Common •Kcevatton
cu m
072
290
362 1
9 04 1
°L      4-
\2 6 2          \RocU wxcavUon
cu m
1.81
723
\2 ft 3         |Unmmurxl Xairm
%
5 0Q
5OO
5 00 1
4-
±
4-
-------- °4------ 4
oL
----------------0 1
-----4
°J
1.7
__
lwHc.hywd
7 X \CoffXBon e«trralk>n \l 7 1 YHock ex evMto^GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
M*i. Rtf- Level; EL 1.170
DwnTyp*:             Roclcim
CcULjvwV, AacvM
Ur* Prkci
Nnourt
\
Mem
iNo. loescniprioN
| L*nKi
Local
USS
Foreign
USS
Total
USS
Local
QuirrtHI«« | USS
Foreign I Total \
□as \         USS           \
A: CIVIL WORKS
10 DfVERSfON WATERWAYS No.1
3.1           PraMntoaries
3 11
MobJtaalior
L.S
1500
15.^
1500
109 249
436 997
546 24?
3.1.2
Lind icquiikion
hi
2 259 82
0.00
2 259 82
0
0
0
0
3.1 J
Slii durance
hi
1 50487
5,779 46
8 474 33
0
0
0
0
SubtolU
10ft,249
436,997
546,247
3.2 Acceti Rgarfa
32.1
Road Imprcwemenl
km
7.909 37
31 637 45
39,546 85
0
0
0
0
324
New Road
km
17.400 61
59602 46
67.003 07
0
0
0
0
32 5
Stream CrosxlrtQ
No
22 598 20
90.39200
112.OT1 00
0
0
0
a
Subtotal                                                                                                                                                             0                            0                            0
3J            Diversion Ini ike
33 1
Earth excavation
cu.m
072
290
3B2
503
364
1,457
1 821
3.3 2
Rock enciveliDn
cu.m
1 51
7 23
BCM
393
711
2,642
3553
3 3.3
Min conc/ele
cum
1806
7231
B0 39
756
14209
55,837
71 047
3 34
Structural concraic
cu.m
25 99
10395
129 B4
450
11 895
45.775
55 473
3 35
Formwork
eq m
10 17
40 55
50 85
1 453
15.062
60 328
75.411
3.3,5
Steal ratofortemenl
T
248 58
994 32
1.242 90
SB
14 665
55665
73.331
337
Unmeuured Heme
M
500
500
500
2 636
11,345
14 152
Subtotal
59.563
235.253
297.617BARO-AKOBO PROJECT Integrated Muter Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultants, Inc.
01-Dec-86
Max. Res. Level: El. 1,110
Dam Type: Rockfill
Inst. Capacity: 12.2MW, 11.4 MW A 21 MW Cost Level:                                                       Jan-9S
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
3.41
Common excavation
cu m
0.72
290
362
18 200
13,177
52.707
65,884
3.4.2
Rock excavation
cu.m
1.81
7.23
9 04
167.700
303.202
1.212.806
1,516008
3.4.3
Earth fill from borrow
cum
1.36
542
6.78
0
0
0
0
3 4.4
Hauling fill material
cu m/km
010
0.41
0.51
0
0
0
0
3.4.5
Earth fill
cu.m
0.45
1.81
226
0
0
0
0
3.46
Lining concrete
cum
33 90
135.59
169 49
5.030
170.507
682 028
852.535
34.7
Structural concrete
cu.m
25 99
10395
129 94
0
0
0
0
348
Formwork
sq.m
10.17
40 68
50 85
0
0
0
0
349
Steel reinforcement
T
248.58
994 32
1.242 90
185
45.987
183.949
229 937
3.4.10
Unmeasured Items
%
500
5.00
500
26 644                106 575                133218
559,516 2.238.065 2,797.581PREFEXVSlBIUITY STUDY
COST CSTiMATE
0*m Typ*'. flock mi
/      1--------------------------------- T~
inaic
i triMw.
Unit Prices
Amount
\
/rtem        /
[No. /oescR^Trcw
1
1 UnMe
Local
US|
Foreign
USS
Total
USS
Local          1      Foreign \                Total         \ 3uanltUee |         USS          \          USS          \          USS          \
A: CIVIL WORKS
4.0 POWER PLANT No.2
4.1            Prelknlnariea
|4.1 1
Mobrtinliori
L.S
15.00
15.00
1500
84 804
339.577
424.471
4 12
Land at         Ion
ha
1256 82
0.00
2.259 02
0
0
0
0
14.1.3
Srte ctearanca
ha
1694 87
6,779.46
0474.33
0
0
0
0
Subtotal
84.594
339.577
424.471
4.2            Acceea Road*
421
Road Improvement
km
7.909.37
31 537 46
39 546 85
8
63 275
253,100
316,375
4 2.2
Naw Road
km
1740061
59 602 46
87 003 07
7
121 604
487 217
509 021
4.2.3
Stream Creating
No
22598 20
00 302 00
112991 00
0
0
0
0
Subtotal
105,079
740,31?
925.396
4.2            Power Inlake
4.3.1
Earth excavalJon
cum
072
2JTO
3 82
110
80
319
398
43 2
Rock excavation
cu m
1.81
723
9 04
0
0
0
0
4.3.3
Lining concrete
cu.m
40 68
162 70
203 38
0
0
0
0
434
Structural concrete
cu.m
25 99
103 95
129 94
450
11.695
48 770
58 473
435
Formwork
aq m
1017
40 68
50 85
1 3SO
13 730
54,918
60 648
43 5
Steal retnlor cement
T
248 58
EMM 32
1 242 90
69
14566
58,665
73,331
437
Unmeasured Mama
U
500
500
5 00
2.008
8,034
10,642
Suh Lot al
42.178
168.714
210,892
4.4            Penatock (auifaca)
44 1
Common excavalion
cu m
072
290
382
2,400
1,736
6960
8 688
442
Rock excavation
cu m
1 81
723
9 04
250
452
1 806
2 260
44 3
Anchor holla
m
1356
54.23
87 79
0
0
0
0
444
Maae concrde
cu.m
1808
72 31
9039
500
9 039
36166
45.196
44 5
Structural concrete
cum
25 09
103 05
129.94
0
0
0
0
446
Formwork
aq.m
10 17
40 68
50 88
2 000
20 340
61±38O
101 700
447
Steal rainlorcamanl
T
748 56
094 32
1 242 90
50
12,429
49J18
62 145
4 4.8
Unmeaaurad Marne
%
1000
1000
1000
4 400
17MMI
21,990
4e.»7
193.580
241.967BARO-AKO0O PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS ConwMarrtt, Inc.
61-Dac-M
1,610
Inst. C
Dam Type:        Rockfill
: 12.2MW, 1I.4WWS21MW
Cost Laval:          Jan-86
Unit Prices
Amount
Item
No.
DESCRIPTION
Units
Local
USS
Foreign
USS
Total
USS Quantities
Local                  Foreign USS                     USS
Total
USS
4.5
A: CIVIL WORKS
Powerhouse (surface)
4.5.1
Common excavation
cu.m
0.72
290
362
7800
5.647
22 589
28.236
45 2
Rock excavalion
cum
1 81
723
904
4,230
7648
30,591
38,239
4.5.3
Earth HI
cum
045
1 81
2 26
2.870
1.297
5,189
6 486
454
Mass concrete
cu.m
1806
72.31
9039
1,036
18,729
74.915
93.644
455
Structural concrete
cu.m
25.99
103 95
129.94
976
25.364
101,457
126 821
456
Formwork
sqm
1017
40.68
50 85
2.990
30 406
121633
152.042
4.5.7
Steel reinforcement
T
248 58
994 32
1 242 90
198
49,219
198,875
248 094
4.5.8
Roofing
sqm
180.79
723.14
90393
162
29 287
117.149
146.437 1
459
Blockwork
sq m
904
3816
45 20
324
2,929
11,716
45 10
Miscellaneous Metalwork
T
723.14
2.892.57
3.615.71
25
18.079
72.314
90.393 1
4 511
Slope Protection
sq m
4.52
1808
22 60
0
0
0
4.5.12
Unmeasured itemi
%
1000
1000
1000
18.861
75.443
M
829.872 1.037.340
-------------- -
94 304 1
Subtotal
207,468
41
h.e.i         1 Common excavation
cu m
072
290
362
cu m
1 81
7 23
904
0     °°L4-       - - - - - °4-------- °-J
°J
\4 6 3             \ Unmeasured Seme
%
500
500
500
Subtotal
o'
0
0
--------------- H
01 ________ oj
0
4.7
------ ■—          a                 ■                        . — \Common mccavaAton
•wttdwarS
\A7A
leu m
0 72
7 0O                         3*17 1               fl too /               5fld4 /               2J4S4 /               29 J22 /
\ A t □       \Uock
» 81
\< 7
1<jm m
L£±Z®
•or 1®                         ajl 43 7                 &           jsm I              rov.jrf /               t     no / —                       ___
°±
L
7 23 UM 1 °
°1
iVGUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Men. LevH: EL 1,410
D«m T yp«i        R ockfllb
Inti. Ctpacrty:      171MW. 1t.4MWl21MW
Unit Prfcat
Unite
Local
USI
Foreign
USS
Total
usi
1        Local QuenllUes [            US I
A: CIVIL WORKS
I
Goal LaveV.
Amount
Foittyn
US*
5.0 DIVERSION WATERWAYS NoJ
S.1 PreWml/iartet
5.1.1
MotWOMItkMl
LS
1500
15 00
1500
62 259
329 037
411 296
51.2
Lind acquisition
ha
2 258 82
0.00
2 259 62
0
0
0
0
5.1.3
S4a cteerance
he
1 694 67
8.779.46
6.474 33
0
0
0
0
Subtotal
82,259
329,037
411,296
6.2 Acceaa Rouda
52 1
Road Imprcwnent
km
7,909 37
31,637.46
39 546 65
0
0
0
0
$2.2
Naw Road
km
17 400 61
69 502.46
87 003.07
0
0
0
0
5.2.3
Stream Crowing
No
22,596 20
90 382 80
112 99) 00
0
0
0
0
Subtotal                                                                                                                                                                0                           0                            0
53 1
Earth excevebon
cu.m
0 72
290
362
503
364
1,457
1 821
532
Ruck txcevelkjn
cum
1 81
723
904
393
711
2.842
3.553
5 33
Meta concrete
cu.m
10 08
72 31
90.39
786
14 209
56,837
71 047
53 4
Structural concrete
cum
25 80
103 95
129 94
450
11,695
46,776
56.473
535
Formwork
sqm
10.17
4066
50 85
1 483
15,002
60,328
75.411
536
Sleel lekifaecemerK
T
248 68
99432
1,242.90
59
14 668
58,665
73 331
5.3.7       | Unmeaimed Itema
%
5.00
500
SOO
2 836
11 345
14 182
Subtotal
59583
230,253
207,917BARO-AKOBO PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultants, Inc.
01-Dec-8 J
Max. Rss. Level: EL 1,010
Dam Type: RocklHI
Inst. Capacity: 12.2MW, 1I.4MW A 21MW
Cost Level:            Jan-OT
Unit Prices
Amount
Item
No.
DESCRIPTION
Units
Local
USS
Foreign
USS
Total
USS
Quantities
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
6.4 Diversion Canal
5.4.1
Common excavation
cu.m
072
2.90
3.62
13.800
9.991
39,965
49.956
5.4.2
Rock excavation
cu.m
1.81
723
9.04
128 800
232870
931,482
1.164,352
543
Earth till from borrow
cu.m
1 36
5.42
678
0
0
0
0
544
Hauling GN material
cu.m/km
0.10
041
051
0
0
0
0
S.4.5
Earth tn
cu.m
045
1 81
2.26
0
0
0
0
546
Lining concrete
cum
24.86
9943
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
5.4.8
Formwork
sq.m
10.17
40 68
50.85
0
0
0
0
549
Steel reinforcement
T
248 58
994 32
1,242.90
146
36,293
145,171
181 463
5 4.10
Unmeasured items
%
500
500
500
19.361
77.442
96.803
Subtotal
406.573              1,626,290             2.032,663GUMFRO HVDROELEGTRIC PROJECT PREFEASIBILITY STUDY
COST EBTIMATE
Ma?., R>«_ L«v*ir Ei, i.eio
oamiyp*:           Rock rm
Inst Capaclly; 12.2MW, 11.4MW fc 11MW
UnN Prlcaa
Until
Local
usi
Foreign
US 1
Total
US I
Quantities
A: CIVIL WORKS
G.O POWER PLANT No J
1.1 Preliminaries
fl 1.1         Mobilization
LS
1500
15 00
1500
107.611
430 443
536064
8.1.2
Lind acquisition
hi
2 259 82
ooo
2 259.02
0
0
0
0
6.1 3
Site clearance
ha
1,69457
6,779,46
B. 47433
0
0
0
0'
Subtotal
107.611
430.443
538.064
C.2          Ac cast Roads
621
Road Improvement
km
7 909 37
31.637.46
39 546 65
17
134 459
537 037
672 29G
622
Now Road
km
17,400.6!
69.602 46
07,003 07
10
174006
698 025
870.031
5.2 3
Stream Croasinfl
No.
22 590 20
90 392 00
112.991 .00
0
0
0
0'
Subtotal
308,465               1233,862            1 >542,327
6.3            Power Inlslto
16 3.1
Earth excavation
cu m
072
2 90
3 62
110
00
319
398
0.32
Rock omcmIIot
cum
1 01
7 23
BO4
0
0
0
0
« 3.3
Lining conciela
cum
40 60
102.70
203 30
0
0'
Oj
0
6 34
Structural concrete
cu m
25 99
103 95
129 94
450
11,695
*16770
sa .473
6 35
Formwork
sqm
10 17
40.68
50 05
1 350
13730
54918
60,040
8 36
Sled reknlorcamant
T
240 50
994 32
1,242 90
59
14,660
58 665
73,331
037
Urvneiiured Name
U
5 00
500 1
5 00
2008
8,034
10,042
Subtotal
42.170
188.714
210.B92
*4           Penstock (surface]
64 1
Common excavdion
cu m
0 72
290
3.62
2,400
1,730
8 050
0666
0.4.2
Rock OKCtvsIkMi
cu m
1 Bl
7 23
904
250
452
1 800
2 250
6 4.3
Anchor bolt
m
1356
5423
67 79
0
0
0
0
644
Mass concrete
cu m
10.06
72 31
90 39
SCO
9030
36.150
45,195
6.4 5
Structural concrete
cu.m
25 90
103 05
129 04
0
0
0
□
640
Formwork
■qm
10 17
40 68
50 65
2000
20 340
0! 360
101,700
6 47
Stool reinforcement
T
246 56
904 32
1 242 BO
B0
12,429
49716
62,143
(6 4.6
Unmoasured Homo
10 00
10 00
1000
4 400
17S99
21999
SubloUI
40,397
103 588
241.M7BARO-AKOBO PROJECT
Integrated Matter Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultinti, Inc.
01-Oec-H
1,110
Dam Type: RockfHI
Cost Level: Jan-98
Amount
< Local
Unit Prices
Foreign T      Total
1 Foreign
DESCRIPTION
Units
uss
USI
USS
A: CIVIL WORKS
Powerhouse (surface)
1 us» 1     USS
Total
65.1
Common excavation
cum
0.72
2.90
3.62
5 76C
4.17C
16 68
20.851
65.2
Rock excavation
cum
1.81
723
904
3.850
6 961
27.84
3                34.804
65.3
Earth fr#
cu.m
045
1.81
226
3.240
1,464
5.85t
7322
6.5.4
Mass concrete
cum
18.08
7231
90 39
836
15,113
60453
75.566
655
Structural concrete
cu.m
2599
103 95
12994
785
20 401
81.602
102.003
6.5.6
Formwork
sq.m
10.17
40.68
5085
2.406
24.469
97.876
122.345
6.5.7
Steel reinforcement
T
248 58
994 32
1.242 90
160
39773
159091
196.864
6 58
Roofing
sq m
180 79
723.14
903 93
136
24.587
98,348
122,934
659
Blockwork
sqm
904
36 16
45 20
300
2.712
10.848
13,560 /
65.10
Miscellaneous Metalwork
T
723.14
2.89257
3,615.71
25
18.079
72.314
90 393 /
6 5.11
Slope Protection
sq m
452
18 08
22 60
0
0
0
6512
Unmeasured Hems
%
1000
1000
1000
15,773
Subtotal
173.50!
63 091
694.006
ft ft
1R R 1 I Common excavation
----------------4
78,864 /
967,507
i~--------------- n
1CU m
072
2” |
352 1
^6 6 2       | Rock •xc-av»Uon
cu m
1 01
-----------------°+     —°-F ---------------H
U
5 00 J
Subtotal
-----
500
7 23 I               904 1    L°L
5 00 |
---------------- —
0/
o
oi
o
--------------
o
\ Common ■iCAwtioc
IrocK
artaS tlurie
_ MV^OFeOd-tfCTKiC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
Uir Ra«, Laval- EL
Dam Type:
frill. Capacity; 11JMW 114MW111MW
Cort Laval*.
/--------- 7--------------------------------------------------- Mem 1
/lYo     JoescRIPTlON
Unll Prlcei
tonmint.
\
UflHf
Local
US I
Foreign
usi
Total
USS
Local
QuanHUet | US I
Foreign I            Total V
□St            \           us*
A: CIVIL WORKS
7.0 DIVERSION WATERWAYS No.3
7.1 Preliminaries
71.1       TmoMMUmi
71 2 f land Bcqulvitloci
7.2 Access ftoadi
IS
15.00
1SOO
15 00
222 634
890.536
1,113,170
ha
2.259 62
000
2 259 62
0
0
01
0
7.1.3          Site clearance
hi
1,694 07
6 779.46
0 474 33
0
0
0
0
Subtotal
222.634
B9O.536               1.113.170
7.2.1
Road irr^fovemenr
km
7 90937
31.537 46
39 546 05
0
0
0
0
72 2
hew Road
km
17.400.61
69.602 46
87.003 07
0
0
0
0
7 2.3
Stream etching
No
22,596.20
90,39260
112,991 00
□
0
0
0
Buhlertal                                                                                                                                                                0                            0
a
7.3            01 vi rlion Intake
73.1
Earth ntuvaiion
cum
072
290
362
923
sea
2873
3.341
73.2
Rock iMcevatlon
cu m
1.81 I
7 23
904
513
1,470
5,800
7 350
733
Mail concrete
cu m
1808
7231 1
00 39
1 626
29 395
117 579
146,974
73 4
Structural concrete
cu m
25.99
103 95
129.94
450
11 695
46776
56 473
735
Fofrnwofk
»q m
10.17
40 65
50 55
1 646
15.774
75 095
53.869
738
Sloil reirtfofcimw'M
T
240.56
994 32
1.242.90
59
14.666
56,565
73 331
7.37
Unmeasured flima
%
500
500
500
3.633
15,334
19 t67
Subtotal
60.501
372,004
402.505BARO-AKOBO PROJECT Integrated Master Plan
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
Max. Res. Level: El. 1,610                   Dem Type: Rockfill Inst. Capacity: 12 J MW. 1MMW 121MW
Unit Prices
Quantities
TAMS Consultants, Inc.
01-DeoH
Cort Level: Jan-M
Amount
litem
|No.
DESCRIPTION
Units
Local
US $
Foreign
USS
Total
USS
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
7.4 Diversion Canal
7.4.1
Common excavation
cu.m
072
290
3.62
42,000
30.408
121,632
152,040
7.4.2
Rock excavation
cum
1 81
723
904
387 000
699 696
2.798,784
3,496 480
7.43
Earth fin from bonow
cum
1 36
542
678
0
0
0
0
7.4.4
Hauling fill material
cu.m/ km
010
0.41
051
0
0
0
0
7.4.5
Earth fill
cu.m
045
1.81
226
0
0
0
0
7.4.6
Lining concrete
cu.m
24.86
99 43
124.29
11,610
288,601
1.154.406
1 443 007
7.4.7
Structural concrete
cu.m
25 99
103 95
129 94
0
0
0
0
7.4.6
Formwork
sqm
10.17
40 68
50 85
0
0
0
0
7.4.9
Steel reinforcement
T
248 58
994 32
1,242 90
427
106,144
424,575
530,718
7.4.10
Unmeasured Items
%
500
500
5.00
56.242
224.970
281.212
Subtotal
1.181,091        <724.366         5.905.457r
GUMERO HYDROELECTRIC PROJECT PREFEASIBILITY STUDY
COST ESTIMATE
.818
lltm I
[No.iDESCRtPTION
Local
Inal. Capacity: Unit Prices
Foralyn
11.2MW. 18AMW
Total         I
US 1          1          U8»
Coat Level
Amount
Foretan
B: ELECTRO-MECHANICAL EQUIPMENT
DAMS AND
US t
|
|l7f                      1 Power supply Io the dam
LS
10000 00
40 000 00
50 000 00
M2
(intake and Bulkhead Gales - Low Level Outttl
-ch
1
10000
40 000
80000
3,200 00
4 000 OO
I 1.3                    1 Htffh Pressure Slide Gate* - Low Laval Outlet
| each
4
3 200
12 800
9800 00
39 200 00
49 000 00
4
Subtotal
39 200
a« aaa
2.0                 POWER PLANT No.1
2.1
Power Intake Galas
each
800 00
3 200 00
4 OOOOO
2
1 600
6.400
6 DOO
2.2
Penstock
T
494 00
1 978 00
2 470 00
313
IM 622
818 466
773,110
23
Inlet Valves
each
22 000 00
88 OOO 00
110 000 00
2
44 000
176 000
220,000
24
.
25
Turbine* Governors and Turbine Auxiliary Equipment— --------------------------------
each
116 000 00
464 000 OO
580 000 00
2
232 000
928.000
1180 000
Generator a and Generator A mm Ml ary Eqikpment----------------------------------------
each
186 000 00
872 000 00
840 000 00
2
136 000
1 344 00O
1 660.000
20
L3
45 000 00
160 000 00
225 000 00
1
43 000
180,000
223 000
27
Sis lion Auxiliary Mechanical L qu ipm e nl                — 
LS
89 000 00
276 000 00
345 000 00
1
60 000
276 000
345 000
20
Station Auskiary Electric at EqiApmenl——
LS
181 000 00              724 000 00
1
181 000
724 000
908 000
2-9
2 10
2 11
Main Transformers-------------------------------------------------------------------------------------
Switchyard Equipment
--------------------------------------------------
Un-TKfl»u.-ed Items _____ ______________________ ____________ „             / -------------------------------------------------------------------------- 8 u bi ol a 1
each
L8
»
38 000 00 110000 00
10
152 000 00 440 000 00
10
190 000 00 550 000 00
10
2
1
78 000
110 000
124 922
1.374.144
KM 000
440 000
490 669
•.4M.I77
380 000 |
550 000 1
824,811 1
8,878.721
1BARO-AK060 PROJECT
Integrated M after Plan
GUMERO HYDROELECTRIC PROJECT
PREFEASIBILITY STUDY
COST ESTIMATE
TAMS Consultants, Inc.
01-Dec-S<
Mu. Ret. Lewi: El. 1,«10
Inri. Capacity: 12.2MW, 18.4MW&21MW
Dim Type:             RockflM
CodLevtl:             Jan-18
Unit Prices                                     1
Amount
i
Item
No.
Local
USS
Foreign
USS
Total
Local
DESCRIPTION
Units
USS           | Quantities               USS
Foreign
USS
Total
USS |
B: ELECTRO MECHANICAL EQUIPMENT
4.0 POWER PLANT No.2
4.1 Power Inlake Gates
each
800.00
320000
4,000.00
2
1,600
6.400
8 000
42
Penstock
T
494 00
1.976.00
2.470.00
341
168.454
673 816
842.270
43
Inlet VeNes
each
26.000 00
104.000 00
130 000 00
2
52.000
206.000
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 00000
1,016,000.00
1.270,000.00
2
508.000
2,032.000
2.540.000
4.6
Powerhouse Crane
L.S.
45,000.00
160.000 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
46
Station Auxikary Electrical Equipment
LS.
261.000.00
1.044.000 00
1 305.00000
1
261.000
1.044,000
1 305.000
49
Main Transformers
each
56.000.00
224 000.00
280.000.00
2
112000
448.000
560.000 I
1410
Switchyard Equipment
LS
120 000 00
460 000 00
600.00000
1
120 000
460,000
600.000
Un
Unmeasured Items
%
10
10
10
163 505
654022
817.577
Subtotal
1.7M.66S           7.1M.2J1           I.M2.7I7
5.0              DIVERSION WATERWAYS No.2_______________________________ ___________ ____________ ____________ __________ _________ ___________ ___________
is.'
\Otwton Gala,
[each
|
800 00 |
3,200 00 |
4,000 00 f
2 I 1,000 )
6,<00 I
6,000 /
Subtotal
1.»OC                   4,400                  4,0007
MiM#r rim
GUMERO HYDROELECTRIC PROJECT
PREFEASlBlLiTY STUDY
COST ESTIMATE
Ntau Ra*. Level: EL 1.1 IB
Inrt. Capacity; 124MW, 11.4MW A 11MW
Dem Type; RoeMM
CortLwt; Jan4*
Unit Prlcea
Amount
1
litem
(No. |des crjptkjn
Until
Local
US*
Foreign
US$
Total
US*
Qtianlttlea
Local 1
US * US*
B: ELECTRO MECHANICAL EQUIPMENT
-I
G.O                   POWER PLANT No.3
6.1
Power intake Gelet
each
60000
3200 00
4,000 00
2
1.&00
6.400
8.000
6.2
Penstock
T
404 X
1 976 OO
2.47O.X
352
173,688
695 552
869 440
8.3
IrM ValVM
each
28,00000
112 000 00
140 000 00
2
56 000
224D0C
280 000
6.4
Turbine* Governor a and Turbina Auxiliary Equipment
each
167.000.X
666.000 X
635 000 X
2
334.000
1 336.000
1 670 000
is
Generator* and Gwwafor Auxiliary Equipment
each
276,OX.X
1.104 000 00
1 360 000 TO
2
552 DOO
2 206X0
2 760 000
66
Powerhouse Crane
LS
45 000 DO
180.000 00
225 000 00
1
46,000
160. TOO
225 OX
67
S lai km Auxiliary Mechanical Equipment
LS
75 000 00
300 000 00
375 000 00
I
75.000
300,000
375 000
6.8
Station Auxilary Electrical EquLpmeni
LS
300,000 X
1200 00000
1 500 000 TO
1
300 000
1.200 000
1.500 000
6.9
Main Traneformara
each
64,000 X
2&5OOO TO
320 000 00
2
126,000
512,OX
640X0
6 10
Switchyard Equipment
LS.
125,000.00
5OOOQ0 00
625 OX X
1
125 000
500 DOO
625 000
e it
Unmeasured Item*
*
10
10
10
179,049
710,195
695,244
SuMolei
7.0               DIVERSION WATERWAYS No.3
1,Ml,437              7.<7*,147            0,147,114
____________________________________________________________________________________________
j71          ~
Inlake Qatce
_           _       __
_
Subtotal
-1 _&oow|
3,200 00 1              <000 00 |
2 J 1,600 |
0,400 |         ' a OOP J
1.B0B                  <.4M                    t.000
8 0               TRANSMISSION LINES
.  _______ 61
.
0.2
Traneirilaatan Una 132-kV hem Gumer o No 1 Io Gambela-Gore
km
21.060 OC
64.240 00
105 300 X
14
2W 640              1,179,300
1.474,200
TranamUaton Una 132-kV from Gumaro No 2 to Gumero No 1
tan
21,060 00
54,240 TO
106 300 00
9
16*640                        160
*47,700 .
63
Tranenwteian Line 132Vv from Gumerc No 3 to Gumero No 2
tan
21,060 TO
64 240 TO
IM 300 00
IS
1 600,560           2,000 TOO
114,17*            J, 131, OK          4.422.10*DRAWINGS
FOR
GUMERO HYDROELECTRIC PROJECTDrawing
GU-l
GU-2
GU-3
GU-4
GU-5
GU-6
GU-7
GU-8
GU-9
GU-10
GU-11
LIST OF DRAWINGS
Title
Project Plan
Project Profile
Reservoir Plan
Gumero Dam - Plan
Gumero Dam - Profiles
Gumero Dam - Cross-Section and Power Outlet Gumero Dam - Spillway Profile and Sections Power Diversions - Plans
Power Diversions - Intakes
Power Diversions - Canal Section and Penstocks Powerhouse No, I - Plan and SectionPROJECT LOCATION MAP
1
0             200       40CK-1 I—I—i___ :__ I
SCALE
MINISTRY OF WATER RESOURCES ADDiS ABABA ETHIOPIA
TAMS - ULG
MEW YORK - LOHOON - ADD'S ABABA
ITaRO-AKOBO MASTER PLAN PREFEAS1BIUTY STUDIES GUbOO HTWOELECTRJC POWER PROJECT
PROJECT PLAN
OoU; October ^996
| D»g No GU - 1M rVAllON IN Ml H HH
Gume*o Reserve*
Normc' Mir. Level El. 1600 — Korma' Max. Leve El. 1610
■th Ofc River
adwo'ks o* Diversion 1
ftp ’465
®ower Cana' Q»|
Penstock 2-0«
I
Diversion 1 Powerhouse
Z“Ei. 13*0
^•adworKs of Df*efs of
r~Ei 1305
Power Ccno- 0-13m%
Canal Q=l3m3/>
Diversion 3 Powerhouse
, isTAsCE IN «'lometers
ministry of water resources
ADDIS A9A0A c TH OR A
TAMS - ULG
NEW YORK - LONDON - ADDIS ABABA
baro—akobo master plan prefeasibility studies
gumero hydroelectric power project PROJECT PROFILE
October ‘996
1 0*5 No GU - 2\8onn
mat1 LEMAN
t.'t'JCBO
MINISTRY OF WATER RESOURCES
ADOS ABABA ETHIOPIA
barq-akobo master plan prefeasibiuty studies
n                uvncm rnTtJir* nrxxuro non icr»T
M
Date:MINISTRY OF WATER RESOURCES
____________________ ADO IS A»ABA ETHIOPIA____________________________ I TAMS - ULG
__________________<v YORK ■ LOMOOM - ADO IS ABABA___________________ BARQ-AKOBQ MASTER PLAN PREFEASIBILITY STUDIES
GUMERO HYDROELECTRIC POWER PROJECT GUHERO DAM - PLANCrest El. U1S.0
Ex I sting Grouw Surface
Guntro River
3 5 I DJversion TynneL
I
^^^^Mientfpi ine of dam
Spillway          Channel Invert El. 1577.5
tpam Crest El. 1615.0
Intake Tower
Existing Ground Surface
e Diversion and Outlet Tunnel
-v-~
Slope PS %
PROFILE ON_DIVERSION AND OUTLET TUNNEL(. Dam
GUMERO - ROCK FILL DAM - TYPICAL SECTION
TAMS - ULG
YORK - LOWOOW - ADO IS ABABA BARO-AKOBO MASTER PLAN PREFEASIBILITY STUDIES
GUMERO HYDROELECTRIC POWER PROJECT OAM CROSS - SECTION AND POWER OUTLET
LONGITUDINAL SECTION THRQUGHjKL^-Dam Crest El. 1615
Spillway Crest EL 1610.0
Grout and Drainage Gallery
EL 1606.0
1
$
/
l
Grout Curtain
0.075 Drain Holes 6)5.0
I
SECTION THROUGH SPILLWAY CREST STRUCTURE
SECTION A - A
_______ 25A-
STILLING BASIN SECTION
r~
\7
\ t__ \
I
MINISTRY OF WATER RESOURCES 1         AOOIS ABABA ETHIOPIA
Z4
/1
TAMS - ULG
MEW YORK - LOMDOH - ADDIS ABABA
NOTE : Drains and Anchors Same as on Chute
BARO-AKOBO MASTER PLAN PREFEASIBILITY STUDIES
gumero hydroelectric power project SPILLWAY PROFILE AND SECTIONS
SECTION B-B
Oett :         October W
\ Dwg Me GU - 7N
Power house
EL 800
Scale 1 50.000
MINISTRY OF WATER RESOURCES
_______________ fcDDlS ABABA ETHIOPIA ________________________________
»               TAMS - ULG
_______________ <EW YORK ■ LONDON - ADDIS ABA8A
3ARO-AKQBO MASTER PLAN PREFEASIBILITY STLIMFC gumero hydroelectric power project
POWER DIVERSIONS - PLANS
j Date :          October 1W
l P»B Ho 611 - 8ELEVATION
UPSTREAM ELEVATION OF SPILLWAY
AND INTAKE.STRUCTURE
Scale 1:1000
PLAN
MINISTRY OF WATER RESOURCES
_____________________ ADO IS ABABA ETHIOPIA_____________________________
TAMS - ULG
_________________ XV YORK - LOMOOM - ADO IS ABABA______________________ BARQ-AKOBO MASTER PLAN PREFEASIBILITY STUDIES
GUMERO HYDROELECTRIC POWER PROJECT POWER DIVERSIONS - INTAKES
D»t« : Octob* 1**
1
Ho 60-9Existing Ground
Surface
GUMERO 3 PENSTOCK AND POWERHOUSE PROFILE
POWER CANAL
TYPICAL SECTION UN SlttPLY SLOPING GROUND
Existing Ground
_ Surface _____
GUMERO 2 PENSTOCK AND POWERHOUSE PROFILE
T
POWER CANAL
TYPICAL SECTION ON GENTLY SLOPING GROIJNn
Mroj penstock and powerhouse PROFILE
ministry of water resources
_ ____________________ AOOIS ABABA ETHIOPIA__________________ _
Tams - ulg
________________ YORK - LONDON - ADO IS ABABA_____________________
baro-akobThaster plan prefeasibility studies
GUMERO HYDROELECTRIC POWER PROJECT
POWER DIVERSIONS - CANAL SECTION AND PENSTOCKS Date :        ocfefef I**_______________ |    0*9 *> W - 10___________________ ,TYPICAL LAYOUT
NOTE:
1 Eoch of the three Power Plants con ton two units
Powerhouse No 1:
2x6 1 MW
Powerhouse No 2:
2x9.2MW
Powerhouse No 3:
2x10.5MW
MINISTRY OF WATER RESOURCES ADCS ABABA ETHIOPIA
TAMS - ULG
___________ NEW YORK - LONDON - ADCS AfiAfiA
BARQ^aKOBO MASTER PLAN PREFEASlBtUTY STUDIES OJMERO HYDROELECTRIC POWER PROJECT TtRCAL POWERHOUSE - PLAN AMO SECTON
Dote: October 1996
I 0*9 No GU - 11APPENDIX 4-1
ITANG DAM
Detailed Cost EstimatesBARO-AKOBO PROJECT
Integrated Master Plan
itang IRRIGATION PROJECT PREFEASIBILITY STUDY
DAM COST ESTIMATE Max- Rea. Level: El. 431.< Dem Type:
DESCRIPTION
A: CIVIL WORKS
DAMS AND APPURTENANT WORKS
Preliminaries
i Access Roads
Diversion Canal
Cofferdam
Embankment Dam
Spillway
Irrigation Intake
1.703,059
7.909
250.366
72.680
8.003.262
1.126,418
189.534
TOTAL 1.0 B: ELECTRO-MECHANICAL EQUIPMENT
DAMS AND APPURTENANT WORKS
®812.237 31.637
1.003.464
2*0,720 32,013.047
* 505.673 758.138
45.414,116
Spillway Gates
Irrigation Intake Gates
406.000
24.000
1.624.000 96.000
coon
an
TOTAL 1.0
430,000
1,720,000
WW
TOTAL BASIC COST                 11.783,723
47,134,010
SU1UI
Physical Contingencies      20%     2,356.746 Engineering and Administration      10%     1,414,047
TOTAL CONSTRUCTION COST | 15,554.522
9,426,943 5,656,IM
62.218.061
it,m:Unit Mc.i
Cot Lj-Met.
ftnwww
AacvJX
Foreign
Tot Al
Local
UM
Fwelgw
1.0 DAMS AND APPURTENANT WORKS 11 PteJfrnfojffoi
S
lotel
US I
US t
QuanlHha
Wl  | US1
A: CIVIL WORKS
f       jfjWoWkrafkxi
1500                 1500
1500
1 703059
6.612,237 |          6,515.297 |
h 4.2       iLaftd acquisition
lha
2,259.82                     000
2,259 82
0
0
00
fl f 3     fsrta c^arince
ha
1,694 87 j           8,77046
S.474 33
0
0
. ■                       —in
S<jW01*I
1,703,053           a,612.237             8,515 »7
t.2 Accaia Ro*da
i 21        |Road Imp/ovwnarH
km
7.BOO 37
31,637.48
39 546 85
1
7909
31 837
39.547
1 22         I Naw Road
km
17 400 61
69 60246
87 003.07
0
0
0
0
1.2.3         Slraam Crossing
No
22 596 20
BO 392 80
112,991 DO
0
0
0
0
SutrtoOl
7.909
31,637
39,647
1.3            Dlwrakm Canal
i31
.
132
Common Encavaflk>n
CLLrn
0.72
290
362
330,000
238.920
955,880
1.194 000
..
1 3.3
Roeli Emanation
cu.m
1 81
7,23
9 04
0
0
0
0
Earth Fid
cum
0 45
1 81
228
0
0
0
0
134
L <ntnfl Conerala
cum
28 25
11299
141 24
0
0
0
0,
1 35
Structural concrete
on m
25 99
103 95
129 94
0
0
0
0
1 i fi
m
10.17
40 86
50 65
0
0
0
0
T
240 58
994 32
1,242 90
i J-r 13n
O
0
0
0
_____ -------- ------ - ------------- '      ■"                         fiuMotal
iJrwnAMUfvd lirrna
■%
500
500
500
11.948 |              47.784
59 730 |
250 666            1,003.464             F ,254,330BARO-AKOBO     PROJECT Integrated Mester Plan
ITANG IRRIGATION PROJECT PREFEASIBILITY STUDY
DAM COST ESTIMATE
Max. Res. Level: El. 431.6 Dam Type: Earth All
TAMS Consultants, Inc.
07-Nov 46
Cost Level:           Jan46
Unit Prices
Amount
Item
No.
DESCRIPTION
Units
Local
USS
Foreign
USS
Total
USS
Quantifies
Local
USS
Foreign
USS
Total
USS
A: CIVIL WORKS
14 Cofferdam
1.41
Foundation excavalion - Common
cum
0 72
290
3.62
10,000
7 240
28.960
36 200
1.4.2
Foundation excavation - Rock
cum
1 81
7.23
904
0
0
0
0
143
Borrow excavation - Earth
cu m
068
271
3.39
48,700
33.019
132.074
165,093
1.4.4
Borrow excavation * Rock
cu.m
096
364
480
3000
2,880
11,520
14,400
1.4.5
Hauling Wl material (over 2 km)
cu.m/km
0.10
041
051
0
0
0
0
1.46
Unprocessed fill (placement)
cu m
045
1 61
2.26
48.700
22,012 |                68 050
110.062
1.4.7
Processed fill (placement)
cu m
136
542
678
3,000
4 068 I              16.272
20.340
148
Unmeasured Hems
%
500
500
5.00
3461 J              13,844
17 305
Subtotal
72.680               290.720
363,400
1.6 Embankment Dam
151 Foundation excavation - Common
cu m
072
2.90
3 62
437,000
316.366
1,265.552
1 561.940 1
1 52
Foundation excavation • Rock
cu m
1.81
723
904
0
0
0
01
153
Borrow excavation - Earth
cu.m
068
271
339
1,316.000
692 246
3.568992
4,461 240 /
1.5.4
Borrow excavation - Rock
cum
096
3 84
4.80
159.000
152 640
610 560 I
763.200 I
155
Haukng Wl material (over 2 km)
cu m/km
0 10
041
051
0
0
oI
0I
H5.6
Impervious core
cu m
2 28
904
11.30
1,581,500 J
3.574 190 ]
14 296 760 /        17.870 950
11.5.7
Unpiocessed Ml (placemen!)
cu m
045
1 61
226
1 316.000 1           594 332 1
2.379.326 1         2974 160
Il 5 B          IP(oceBB«d fa (placement^
cu m
1.36
5 42
6 76
0I               01
010
cu.m
3 3D
13 56
16 95
66,000 |                223 740 1
894 960 1         1,118,700 1
\> ft 50                                     UanalUona
cu m
3 30
13 56
16 95
481 OOO 1      f 630 590 /
\5 ft 55 \* ft 53
\' — '
I. plac-wrvwM)
UhMu.u                                                    diaina
A
cu m
1.13
4 52
5 flft
210 200 !                   7J7 526 /
6 S22 36O 1 8,152,950 /
950 104 /                   1,187 630 7
T
•x.
11 50
117 tw
*“■>
*5 20
*•< 97
9 IM
54 50
«w>4 on
A <N>
oI o1
O1 o/
/                     Mt IO« /
o/                    OJ
of                      of
-<Jf /                f ar»A a »v /Mmk. Lavwfj el. 4J1.*
Treat
lEartMtn
Unft Price* | Locaf               Foreign
Ajraunl
\
Jrtm          /
[No. /DESCRIPTION
/ UnNa
1 Mil
vtl
Quant ft la l
Local 1
Dll 1
FoiaVgm    \
1<AM              \
U31          \          US 1         \
A: CIVIL WORKS
1,6           Splttwty
fl 6 1
- CofTVTW
cum
072
290
3 62
16,000
13 032
52.128 I                 65 160 \
183        IBulk excavation - Rock
cum
181
723
904
10 ODO
32.544 '
130,176 |              162 720 \
11.63        1Structural excaratfon ■ Rock
cu.m
452
1806
22 60
0
0
o*
—
fl.6.4         1 Masi concrete
leu.m
1906
72.31
90 39
37.213
672 737
2 690,940
3 363.683
165
SlructuJti concrete
cum
2S99
103 95
129 94
5850
152030
608119
760,149
1.6 6
Formwork
iq m
10 17
40 68
50 85
5.490
55,633
223 333
279 167
167
Steel reinforcement
T
240.50
994 32
1,242 90
468
116 335
465 342
581677
168
Onllmg for drains
m
11 30
45 20
56 50
210
2 373
9492
11 865
1.69
Drilling for growing end drefoiffrom gall.)
m
15.02
63.27
79 09
250
3954
15818
19 773
46 10
Anchor b (inci drilling and grouting)
T
2 962 96
11,931 05
14914.81
67
19.966
79,943
99 929
16 11
Grouting
T
112 99
451.97
564 98
35
3.956
15819
19,774
1 6 12
UnmeiBuced Hems
%
500
500
500
53 639
214 558
260 195
Subtotal
1.120.418            4,505.073             5,632.091
17             Irrigation Intake
1 71
Common [■cevalkm
cu.m
0 72
290
302
1 000
724
2896
J.620
172
Rock Excavation
cu m
1.01
723
904
0
0
0
0
1 7.3
Earth Ft®
cu m
045
1 81
226
0
0
0
0
174
Lining concrete
cu.m
40 66
162 70
203 30
0
0
0
0
175
Structural concrete
cu m
25 9U
103 95
129 94
2025
52 620
210 503
203,129
176
Formwoifc
&q m
10 17
0 68
50 65
6,075
61 7B3
247 131
308 014
177
LLL-T------
] 1 7 fl
Steel reinlorcem«nl
T
246 56
994 12
1,242 90
263
05 377
261.506
320.683
U
f °--------
Unfnaaauiwd Itero                           .
%
5 00
500
500
9025
36 102
4S 127
Subtotal
100,534
750.130
947 672
?sAPPENDIX 4-2 ITANG IRRIGATION PROJECT
Economic AnalysisTable I: Economic Return by Crops
C*i"n
tfpar i             W2
J        Vr* 4
950
’ 050
i.soc
3MC
■jnrC rrflE# '
4Ji2
4 513
4.512
i    Stj
2.500
4.512
4 ?W
4 512
4415
4.415
tf29|
•T
a?«
4.415
JJ53
»3?4
4 51C
<514
’1.2K
4,510 4.J7Q
*w r
VwJ             itor J
tad
Output K giTi#
mo
1.375
3     i«
4 370
3 COO
9.-300
ecortwnifl prte* -
i 373
1.373
i 173
i 373
OroM r^anut p*r harfsrt
5.034
4 311
5 541
fl.M5
1 MS
MpUlM-Bnfhi
6B4
Mfil
1 MS
1.013
1 fill
MM rwifliM paj Mcfrw ^8im
O»
3.431
<553
5452
Ufl
SofpftO"
Output K^l«a
tcEXKxniic pnc* - Birrrtptf
Greaa rmnu* par nactirt | HhT)
7wf               TMf?              WJ
tart            VevS
1 U» 2 200 3 7W 4 300 l ODO 1.33C 1 JSC i ISC ’,330 1 IK 1.739 2 928 4.921 5.320 SIM
input Corti - Biifftia                                                            601                K0           1.025           1.013           1.013
Mat manua par hectare iB^rrl
5aya Bwrs
Otrtptfl Kg^ha
tcoflttftc prica - Btrrrtoa
Grai rw*anua per fttcuft ^Birri
^chi Cobs - Ou-rrTia
1.121           2.044            am              4J07              4J0T
’’'t* .                W2
tad
tat
*»ir5
2 t«             2.970            t S15           5,’BO          I.OOG
-8fl
“H                7M                 r«i
j
j*t
p^r hectare f|im
u«            2.540               3.W           < 729            4,72f
US              BM                 «a
»B5 kSJ5 3,074 1471 3JU
Output K0toB
Eemmie
pric<. .
ro*a rwvnM* p»r h*cur» ^rn
Cows - Hier/ha
W1
tat?
r«^4            YMfS
4 3M               4 t-M            fl KO              ’.2K           ■ ,XM 010                H'O                nO             BIO-              ■10
5 103               $ 346            5 540             $632              $ m 3 236             3 235            J 225              j za           3.52fi
i.m                1120           3.343             1WS           J.Sfifi
wr '
r i&nr2
Vfrar J
rw4
1 KO
J.50C
3 JM
* sec
2*W
2.490
2<W
J 4W
3 735
5 225
1715
f ?D5
1 354
l OM
1.C54
1«7
2,M1
L1T0
Jin
10,141
'** •*""I®!"1
?.6M
1.119
2.9C9
225
1.644
6mt2
3 2S
1.11*
3 637
225
3 412
3 IW
1.-19
4J0S
225
4.MJ
4S0C
1 111
<034
as
<H1 _
4.5®
i.119
55M
125
4.H1
9 50C
1611
354?E
h»>i
- ^trr/he
TWO
2«1
'•78’
1,4«
11,121
? 500
2611
35 4?C
3^6
UB24
owe
24*1
15 470
34«
11034      3X«JTable 2: Cropping Build-up (ha)?
7014          701I
moJ     MO
MQ
---------- -
»rl         1017
S~i
*i
MO           MC.1
MO
8M
MO
580
MO
MO
MO
2011            rait         TWO            M3l'           awl
M0|           MO,        MD 1
MO
MO
MO
MO
540
—
5B0
»=
MO
MO
MO
MO
540
MO
MO
MO
MO
.*1
MO
MQ           MO
MO
580
MO
MJ
MO           MO             MQ4             MO   “ MO
MD MO MO MO MO
MO
_
Mo MO
54,1
MO         5flO             5«         1 MO           MO  i 5«
MO           MO            MO
- MO
MO
MO            MO           580
5*0 MJ MO
540           MO           580
MO
MO
’»
MO
MO  b mo1 MO MO
100
r“
MO          54O           MO  1
MO           MQ          580
L -------
MOI
.
MO MO
MO MD
MO            MO
MO               Maj
_,T.
• •' •
MO           540              5»
MO            MO            MO              MOI
-
MO
1MO
MQ            MO
5M
MO#
MO mJ
Cwfliuilllitv
J «7) 4.M4          KM4          r i44           MM           i.m           »,1»           1 ,m
i
1 V3 033 j
1 tin i •JJSJ
I         170«|     JOOP               3WJ         JW<
W3          WOi          W|        2WH
MIO         JCf r           »FJ        JOPJ
/             ■■■HI I
i T
40C
400 «0           *00
400^
*00          400          4W
400
400 400
400 40U
400
7014 7OF3 wpl
400           400
MIT TOPI Nir JOJd w> -Will
400 400 40fl 400 « 40Q J
400
400
400
400         400
400 4M
400 400
«
400            *00
400
400
400
400
400
400
400            400           400           400
400           400           400           400
400             «0           400            400
400          4 DO          MW J
•0               «           400           400           400           <00             *00 j
400           <X>           400           400          4D0                             400             •»               tool
4W          4D0           4Q0
400               «          4Q0          40Q           400
1
400            400           400           400           400
■
400 400
400
400           400
400           400
4CJ0            400
•M
400           400           400           400           400           400 Q
400           400
*00            400
400            400
4W
«,               «
*00           400
4«J
400
400
4M
*oo^
400
4TO
400
,
400
400
400
400
400
400
4 DC
400
4M
•on
«XJ
400
-
<00             400            4M
-—
k—
400
*Q0
400
400
<0
400
400
400
_ ____ I
“ 400 400 fl
400           *W A
*»             4w y
400           400 i
40Q «yj i]
400
400
4X
L—
1.
______
—
I’
t--------
------ -
—
1444
—
1400
—
— 
-
400
«M
400
400
400
400
*31
490
•00
400
400
400
400
400
—
400
*00
400
<2S
•00        u»    IM4
ZJMM
~>,104          )*0D            <•«
_____ _
A.4M
I.1M)         IM*
4.000          t m              MM i      mm
400B
400 fl
400 1
ml
4 413 ||
3Table 3: Benefit Build-up (Birr ,000)
/1
Table 3*. Benefit Build-up (Birr ,000)
2015
1.015 J
2015 i
?oifl             2020           2021
1 015             1015            1.011             1015            1015           1.015
1,015 I 1.015
1 015 t                 1015
1015             1015            1,015
1.015
1015 1.0I5
1,015 1015
1
1.011 1015 1.015
1 015 1.010 1.015
1015 1015
1.015 1.015
1015 1.011
1015            1015            1015            1 015
1 Oil
—
1015 1.011
1015
1015             1015              1015           1 011 1.015           1.015            1 015            1015
1015             1015           1.015            1011
1011            1015            1 015
1.011            1015            1 015
1015            1015            1 015
20221
1 Oil!
1.0151
1015 J
1 015 I
1 019 1
1 015 I
1 019 1
10161
1.015            1015            1 015            1 019 0
7M
•IT
>*•
1015
7W
• IT
3«A
1.011
1.019
TM
• 17
}«•
1016           1 016            1019            1 Q15 .        * 015 I
1015           1,015 i         1.015 i          1015 (
1.015 1
1011             1 015 J        1 015 t           ion          ’ 0,5 il moi          i 016 .          1011 [        1 O»5           1 U15 I
•17 1 1 1 1 O»9 |
rw [
»,©»• f
f O»« ff
»•
v •••
«>.?•• i      «4.       I             «• '
WO '
uMJ r «o  /Table 3: Benefit Build-up (Birr ,000)
SummaryFinancial Costs ($ million)Table 5: Cost Benefit Analysis
Cost Benefit Scream(BIjt million)
tut u%DRA WINGS
FOR
1TANG IRRIGATION PROJECT■       -           - ' i
--End of Main Canal
PROJECT
LOCATION
Mian
PROJECT LOCATION MAP
0      200 4C0km
I I 1—J
fuiProuawn
Irrigation Intake
[^Protection Dfafc J_______ :
MINISTRY OF WATER RESOURCES
ADDIS A8A0A ETHlOf>AU Ml
lf6£MO
—-
ftMMM’f C*’*' ' J'*''1*’*' 1
_______ T«Ft‘lfT €•»♦*
CMltdV   ©»■•'•   '   1««***«*F   1
Tari.arr
O”  *«•»!’>• 5 »»*'•*’
O*
^X ■•••*
B«««rral*
ministry of water resources
ADOlS ABABA ETHIOPIA
TAMS - ULG
NEW YORK - LONDON - ADO»S ABABA
BARQ^AKOeO MASTER PLAN PREFEASIBILITY STUDIES
ITANC KRiGABOl PROJECT
LAYOUT
Dote: October 1996
I Dwg No IT - 20ARO                  MASTER PLAN PREEEASJ0IUTY
I TANG RRjQATKX PROJECT
HANG DAM - PLAN
| Date: Octob*        £ 1996
| Dwg No IT - 3Drainage layy
^rmal Water
Level
Max Flood Water
EL 433^^
.60    Stripping    Under Ban and Blankets—
W 'AUZ'A J IJ '
□pStre3fl> Impervious Blanket
IT ANG DAM
TYPICAL section
ministry OF WATER RESOURCES
ADO IS ABABA ETHIOPIA
TAMS - ULG
A DO IS ABABA
October WH
HANG IRRIGATION PROJECT HANG DAM CROSS - SECTION.
I Ow« W» IT - VrENTERllNEJ^-^
■<» Wool wiftr
tL LIU
SECTION ON gPHLWAY AND STILLING BASI_NI
______ Gr®uo«
Cr«*t «f O»*«
Water Larel
Canal Invert
Secondary Canal offtake
I fngth in kilokters
HIMIFTWT or VATER ■£SOURCIS
l»Hl macOtA
TAMS - IH.G
Lg
AWO AK0
-    ^° mast to rtAM rautASinuTY rrvoitsrttVATION IN MtfERS/
.4farm canal
I
MINISTRY OF WAIER RESOURCES
ADDIS A0AHA ETHIOPIA
TAMS - ULG
o 50 too 1bd JOO SCALE
NOTE:
5LJ1TADLF FOR ONE OR MORE FARMS COVERING A TOTAL AREA Of 20 HECTARES.
_____________ ____________ NEW YORjC - LONDON - ADDIS AfJAJJA_______________________________________
BARO-AKOBO MASTER PLAN PREFEASIBILITY SWDIES
typical on farm gravity IRRIGATION 5YS1EM LAYQUT
Oalfl;
Dwg Na IT-14Typical For Excavation
*Mm. Free Soard
Mam Canal - O.6m Oislr bularies = 0.3m
NOTE This SecHon Is Applicable to Maiaranal and Distributaries
Not to Scale
I*Min, Free Board
Main Conol - O.6m
Distributor ies =0.3m
NOJ£ This Section Is Applicable io Malncanat and Distributaries
Not to Scale
MINISTRY OF WATER RESOURCES
4001$ A BAP A ETHIOPIA
TANS - ULG
row - loMOOH - ADDIS A»*BA
BARO-AKOEJQ MASTER PLAN PREFEASIBILITY STUDIES
ITANG IRRIGA7
TYPICAL CANAL 5EC1
ION PROJECT
'ION ON FLAT TERRAIN
Oif<             Ocfot+r l»»4
OvB * IT-09INat to Scale
MINISTRY OF WATER RESOURCES
AOOI5 ABABA ETHIOPIA
TAMS - ULG
_____________ HEW YORK - 10 NOON ■ A DO IS ABABA BAR0-AK08Q MASTER PLAN PREFEASIBILITY
ITANG IRRIGATION PROJECT
TYPICAL PROTECTION DIKE SECTION
Dali CKIobir
Dwg Hi IT-10Stepdown Transformer 13 KV Power Line
Manhole
Pumping Stat TrajhratK-
Roadway Hln 0.2m. Thick Coaraejase Hln 0 3m Thick
■JtgLJWlJ
From Collector Drain
Flap Valve
| 3.5m mln
6 m mln
''■\Compacted F](£
+
Stoplog Groove^
1
Stone Protection
mln 03m Thick
MINISTRY OF WATER RESOURCES
AOOIS ABAI* ETHIOPIA
TAMS - UL6
MEW YWW - LOMDOM - A PC IS AiABA
BARQ-AKOBO MASTER PLAN PREFEASIBILITY STUDIES
ITANG IRRIGATION PROJECT
TYPICAL DRAINAGE PUMPING STATION AT FLOOD PROTECTION DIKE
Not to Scale
pate ;• OctM>*r rt»*
Dvg IT- HSecondarv__Cana^_S
OCS-4-4
LEGEND
Main Canal
Secondary Canal ( Distributary) Tertiary Canal (TC)
Quaternory
Main Drain
Secondary
Conol (QC)
/ Collector Drain
Secondary Collector Drain
423
►-3-2
7 l/Y.
Tertiary and Quaternary Drains Check / Control Structure
Tail Scape
NOTES;      I
-Service   Roads,   not   Shown   Are   Located Along , Canals and Pressure Pipes
2    -On Farm Canals / Drain not Shown 3    ’Oft Takes not Shown
MINISTRY OF WATER RESOURCES
ADDIS ABABA ETHIOPIA
TAMS - ULG
2
NEV YORK - LONDON - ADO IS AS ABA
Approx Scale
BARO-AKOBO MASTER PLAN PREFEAS 18ILITY STUDIES
I TANG IRRIGATION PROJECT TYPICAL IRRIGATION SECTOR GRAVITY SYSTEM
*• IT-12Main Canal
_ Control Building
- Service S Machinery
/ Pumping Station
LEGEND
,,;_M$sure Plpe
Corner Arm
Structure
-
Main Canal Secondary Canal Check / Control Turn out / Off take
n ( Storm Drain I
kJ i
Off    take    /    Pumping    Station Burled Pressure Pipe
Center Pivot Sprinkler with Corner Arm to Irrigate Circle Plus Corners
Solid Set / Movable Sprinkler System
W7h          Building
\ So lid
Set orjloxablejpr!!^er_ System
Main Drain Secondary Drain
NOTES:   I
- Service Roads, not Shown Are Located Along . Canals and Pressure Pipes
2 -No Surface Field Drains or Levelling Required
MINISTRY OF WATER RESOURCES
_____________ AOOIS ABABA ETHIOPIA__________________
Center Pivot
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Summary of Baro-Akobo River Basin Master Plan - Volume V

Summary of Baro-Akobo River Basin Integrated Development Master Plan - Volume V: Prefeasibility Studies

1. Background

This volume presents prefeasibility studies for three high-priority water resources projects in the Baro-Akobo River Basin, Ethiopia:

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

Key Limitation: Studies were constrained by lack of recent topographic data (only 1:50,000 scale maps from 1977 available) and insufficient geotechnical information.

2. Geba Hydroelectric Project

Project Details

Location: 60 km east of Gore on Geba River
Components: Storage dam (45m high) + two downstream diversion systems
Capacity: 112 MW (Diversion 1) + 72 MW (Diversion 2)
Annual Firm Energy: 962 GWh
Reservoir: 66 km² at full pool (El. 2170)

Key Data

Parameter	Value
Mean Annual Flow	35.7 m³/s
500-year Flood	631 m³/s
Construction Cost (1996)	$252.76 million
IRR	16.4%

3. Gumero Hydroelectric Project

Project Details

Location: 27 km west of Metu on Gumero River
Components: Storage dam (35m high) + three downstream power plants
Capacity: 12.2 MW + 18.4 MW + 21.0 MW
Annual Firm Energy: 271 GWh
Reservoir: 37 km² at full pool (El. 1610)

Key Data

Parameter	Value
Mean Annual Flow	8.66 m³/s
500-year Flood	462 m³/s
Construction Cost (1996)	$99.78 million
IRR	11.4%

4. Itang Irrigation Project

Project Details

Location: 30 km west of Gambela on Baro River right bank
Components: Dam + irrigation system for 53,147 ha
Cropping: 40% sugar cane, 60% diversified crops
Water Requirement: 1.1 l/s/ha (peak)

Key Data

Parameter	Value
Mean Annual Flow at Dam	395.1 m³/s
Reservoir Active Storage	139.4 MCM
Estimated Sedimentation	13.6 MCM/year
Soils	Mainly Vertisols (59%) and Cambisols (27%)

Implementation Schedules

Geba Hydroelectric: 6 years from feasibility start (potential 2004 completion)
Gumero Hydroelectric: Staged development (2005-2019) to match regional demand
Itang Irrigation: Phased development over several years

Environmental Considerations

All projects include environmental assessments covering:

Resettlement (28 households for Geba, 7 for Gumero)
Water quality management
Sedimentation control
Fisheries and aquatic ecosystems
Disease vector control

Note: All cost estimates are at January 1996 price levels. The document emphasizes that more detailed surveys and feasibility studies are needed to address data limitations before implementation.