THE FEDERAL DEMOCRATIC REPUBLIC OF ETHIOPIA
MINISTRY OF WATER AND ENERGY
ETHIOPIAN NILE IRRIGATION AND DRAINAGE PROJECT (WORLD BANK FINANCED)
FEASIBILITY STUDIES OF ABOUT 80,000 HA NET IRRIGATION AND DRAINAGE SCHEMES
FEASIBILITY STUDY FINAL REPORT
VOLUME 10: ENGINEERING SURVEYS, INVESTIGATIONS
PLANNING & DESIGN
SR-04C: GEOLOGY, HYDROGEOLOGY AND GEOTECHNICAL INTERPRETIVE REPORT (PARTS 1 A 2)
tialcrow
IN ASSOCIATION WITH
GENERATION INTEGRATED RURAL DEVELOPMENT (GIRD) CONSULTANTS
ADDIS ABABA. ETHIOPIA
MAY 2011Federal Democratic Republic of Ethiopia
Ministry of Water and Energy
World Bank Financed Ethiopian Nile Irrigation and Drainage Project Feasibility Studies of about 80,000 ha net Irrigation and Drainage Schemes Feasibility Study Final Report
UPPER BELES IRRIGATION & DRAINAGE SCHEME
Volume 10: Engineering Surveys, Investigations, Planning & Design
SR-04C: Geology, Hydrogeology & Geotechnical Interpretive Report
Part 1 of 3: Main Report & Annexes A - D Part 2 of 3: Annexes E - H
May 2011
Hakrow Group Limited and
Generation Integrated Rural Development (GIRD) Consultants
PO Bom 102175. Comet Building (Sth Floor) Hade Getxesetassle Road. Addu Ababa, Ethiopia Tel •215-1 (0) 116 63 09 92 Fax *251-1 (0) 116 63 09 91
Th* Report has been prepared In accordance with me rtsuucbons of lhe Federal Government of Eltopu. Ministry of Wafer and Energy for lhev sole and specific
use Any other persons who use any information contained herein do so al their own
risk
© Halcrow Group Limited and Generation Integrated Rural Development (GIRD) Consultants
2011Halcrow Group Limited and
Generation Integrated Rural Development (GIRD) Consultants
PO Box 102175 Comet Building (Sth Floor)
Harte GebreseUwe Road. Adds Ababa, Ethiopia
Tel *215-1 (0) 116 63 09 92 Fax *251-1 (0) 116 63 09 91
This Report has boen prepared inaccordance with the mstrucbons of the Federal
Government of Ethiopia. Ministry of Water and Energy lor their sole and spoof*
use Any other persons who use any nform a boo contained heron do so at thee own
risk
© Halcrow Group Limited and Generation Integrated Rural Development (GIRD) Consultants
2011Jb/Ari^div Ndf
rft.^ Prowwtf Pv^r
feasibility report structure
Volume 1: Main Report (Plus Annexes)
Volume 2r          Water Resources
SR 01A Water Resources Volume 3:          Irrigation Development
Volumes 4
& 5:
SR-OlB: Irrigation & Drainage Development
Soils, Land Use A Suitability
SR-02A. Soils, I-and Use & Suitability Pan 1 of 4: Main Report
Part 2 of 4: Annexes A, B fit C
Part 3 of 4: Annex D
Part 4 of 4: Annexes E - N
Volume 6:          Land Resources & Agricultural Development
Volumes 7
& 8;
SR’OZR: Irrigated Agriculture & Agro economic Development SR-02C Ijvcstcck Development
SR-02D; 1-and & Watershed Management and Forestry
Resource Uacn & Socio-Economics
SR-O3A: Resource Users and Sodn-rcunumics
Pari 1 of 5. Summary Report (Left & Right Banks) Pari 2 of 5: SDAs 1 & III on Right Bank
Pan 3 of 5: SDAs JIT * IV
nn
 1-cft Bank
Volumes 9,
10& 11:
Part 4 or x Survey Data /Xnnexcs (SDAs 1 III on Right Bank) Part 5 of S Survey Data Annexes (SDAs IV 4k [V on Left Bank)
SR-03B Rrscrdemeni
Engineering Surveys, Investigations, Planning & Design SR 0*4A: Engineering: Irrigation & Drainage Works
SR-O4B: Engineering. Storage Dam
SR 040 Geology and Geo technical Interpretive Report
Pan 1 of 3: Mam Report & Annexes A - D
Pan 2 of 3: .Annexes E - H
Part 3 of 3: .Annexes 1 - P SR-04D: Topographic Survey Works
Bdtes M        i Jaimr 10
I July ?ni JMiwtry tfW'atrr & Ewq
Ettiofut Sik frntft** a*d Dmujff Pw*rf
Volume 12:          Environmental Status, Financial & Economic Analysis, Stakeholder Consultations A Study Terms of Reference
SR 05; Environmental Status
SR 06: Financial A Economic Analysis
SR-07: Stakeholder Consultations
SR-08 Study Terms of Reference
Maps and Engineering Drawings, A3
Map Albums, Al
Mam Album
Detailed Soils, Land Use A Suitability Album Topographic .Album
Jkk-A F4 «Vulumc in
iiFederal Democratic Republic of C
/!
Ethiopia
/
Ministry of Water and Energy
World Bank Financed Ethiopian Nile Irrigation and Drainage Project
Feasibility Studies of about 80,000 ha net Irrigation and Drainage Schemes Feasibility Study Final Report
UPPER BELES IRRIGATION &
DRAIN
r SR-04C:fceology, Hydrogeology and
z" Geotechnical Report
PartiT'of 3  Main Report & Annexes A to
xz
f&^'Mayloi 1
Halcrow
in association with
Generation Integrated Rural Development (GIRD) ConsultantsFederal Democratic Republic of Ethiopia
Ministry of Water and Energy
World Bank Financed Ethiopian Nile Irrigation and Drainage Project Feasibility Studies of about 80,000 ha net Irrigation and Drainage Schemes Feasibility Study Final Report
UPPER BELES IRRIGATION & DRAINAGE SCHEME
SR-04C: Geology, Hydrogeology and Geotechnical Report
Part 1 of 3: Main Report & Annexes A to D May 2011
Hftkruw Gruup Limited and
Generation Integrated Rural Development (GIRD) Consultants
PO Box 102175. Comet Buttng (5<h Floor)
Halle Gebresekass* Road. Addis Ababa. Ethiopia
Tet *215-1 (0) 11663 09 92 Fax *251-1 (0) 116 63 09 91
www.hakrow oom
fhn Report has been prepared in accordance with the instructions of the Federal
Government of Ethiopia Ministry □< Water and Energy for their sole and specific
use Any other persons who use any information contamed herein do so al their own
nsk
© Helcrow Group Limited and Generation Integrated Rural Development (GIRD) Consultants
2011FttM Dfm,^
ofEfafiJ. Mivffy of V iter e?Ewr&
.Vri JrnjHfiffrt pad DfiJifft^f Pr^nl
FEASIBILITY STUDY FINAL REPORT
UPPER BELES IRRIGATION & DRAINAGE SCHEME
SR-04C: GEOLOGY, HYDROGEOLOGY AND GEOTECHNICAL REPORT PART 1 OF 3: MAIN REPORT & ANNEXES A TO D
CONTENTS
1 INTRODUCTION AND SITE DESCRIPTION
7. / CMyrrfrw Content of Mri Rrporf
f.2       Prtftrt LecuJ/on arrd 7
7. J     If 7r andztrnsuv
7.4             Prvpojtd Cwtevctma
2 REVIEW OF EXISTING GEOLOGICAL INFORMATION
2. 
t hnmjry
2.2      Pubfahrd Gcohgiarf Afaps and R^rtr
2-2.1 1:2,000,000 scale Geological Maps of Ethiopia 
2-2.2 1:250,000 scale Regional Gcolog>caJ Maps
23       Abtey Bornt Maftetpfofi, BCIiOM, 1998
2.4      Riant Water Rfjwire and lm^non S/Ndai
J GROUND INVESTIGATION SCOPE AND METHODOLOGY
J. 7 InfrodjtaM*
3-2
3.3       Rziv» and r )jf of fLxu/rn^ In formate™
33.1      Existing Ground Investigation Dau
3.3.2    Soil Survey Mapping
33.3     Sooo-ecunomic surveys
3.4        R/wo?/ Jwn& Gwitfui/Mapptn& and ropognphit Con fro/
f. 3     CinwmuZ iFrrqa/fon jQna Groand                  IF We
3.5.1    SummaryF
33.2      Drilling Investigations
3.5.3     Geophysical (resistivity) Surveys
3-5.4 1 rial Pitting and Hand Auger Investigation
3.53 Laboratory Tea ring
3,<5 Danr Jjf7f dW Rrjmwr H rrtf Gmutd Imvteigateon IF7nt
3.6.1     B ackground and Reconnaissance Walkover
3 6.2 Summary of Dam Site and Reservoir Area ground investigation work. 3.6.3     Drilling Investigations
3.6.4     Geophysical Surveys
3.63 Trial Pitting
3.7             Ground Invfjtrgation R/Wl
11
1 f f f
12
12
73
f 4
17
77
77
20
20
20
20
20
24
24
25 26 27 30 37 31
35
36 37 3B 38
tF&M Dfowri
of Elhopa. SUourry ofW'atrr Cu Ewij,
Erwpwjr iViir brtgsfttta and D^aia# Pmied
3.8      HjdngnbgKal VMnrk
4          REGIONAL GEOLOGY
4.1       Intjodadton
4.2       R^rcru/ GrcAp
4.2.1    Bisancnt Metamorphic Rocks
4.2.2    Post tectonic Granite
4.2.3    Mesozoic Sedimentary Rocks
4.2.4    Tertiary Volcanic Rocks
4.25 Quaternary Volcanic Rocks
4.2.6          Recent Deposits
4.3       StHiJuru/ Gtofog)
5        DAM SITE AND RESERVOIR AREA GEOLOGY
5.1       InfroduitioK
5.2       Pnjtct Ana GnfogtcaJ Ovrnw
5.3       Dam Site anti R/jrrwrr Ana Topograph
5 4      Rrjtnoir Ana Geo log
5.4.1    Introduction
5.4.2    Bedrock Units
5 4 3 Superficial Deposits
54.4     Structure
5.5       / )am Site Ana Geology
5.5.1    Sumnun' of Borehole and Trill Pit Results
5.5.2    Summary of Geophysics Results
5 5 3 Left Abutment (approximate chainage 0 - 294m) 5.5.4    Central River Valley (approximate chainagc 294 — 434m) 5.5             5 Right Abutment (approximate chainagc 434 - 1,205m) 5.5.6          Spillway Area (Saddle)
5.57 Structure
6     COMMAND IRRIGATION AREA GEOLOGY
6.1       iHtnufotiftOf:
6.2 
6A Bedrik GatfJ
and Soil Survey
6.3.1    Basement Rock Units
6.3 2 Ternary Volcanic Rocks (Basalts)
6 3.3 Dolentc intrusive ruck
6.4      Super-fatal (Geo It chuna! Sot/) Ufttlj
6.4.1    Topsoil
6 4 2 Vertisols
6.4.3    Reddish Brown Silt/Clay (Residual Soil)
6.4.4    Yellowish Grey Gravellr Silt/Clav Residual Soil / Completely Weathered
Basalt)
6 4 5 I lighly to Completely Weathered BasaltJ-WdZPnwMTOA;- E/^qfwM Nli
4
•/Fjftr r - t wm
Mtf DrjajJFf Prwm
6 4.6 Colluvium
6.5     Slrviturf
7          REGIONAL HYDROGEOLOGY
7. /    Otytriivtr of HidrweoJai^a/ ylfff/Jmtnf
7.2      R rww of fiwAfljt 1 
In/crmaffon
7.2.1      1 2,000.000 scale Hydrogeological Map of Ethiopia
7.2.2     Abbay Rrvrr Basin Mister Plan Study (BCEOM, 1998)
7,23 Hydrogeological S tudy o f the lam Bde& Sub-Basin s Groan dwai ex. SMEC
2008
7.2-4 Review of existing water supply schemes and Worrda / villager comments
7. J Jjwwtfp
PROJECT AREA GROUNDWATER DATA
8.1       I nJnrdwfiM
8. 2       [1am Sift and RtJtrwtr z!zw Gruifndafakr ObjcmftW
8.2 1 Surface Observations
8-2-2 Ground Investigation Observations and Moxutonng
8 23 Permeability Testing
8 2,4 Groundwater Wells
£ 3       f ammand sbra Gmundn^aftr Ohftna/ionf dtrnng Cmund Iwritigationr
J
8.4       Command . l nr a Well Pour! Irnwr/ary
8.5 Command .'Ina PbfMt Whaler Supply Survtjj
8.5.1 Potable Water Supply
8.5.2 Potable Water Supply Provided under the Tana 13cles Project
8.6      Population and PeM l^tfrtrr Demand
8. 7 pjr/Mfr PIF’J Prvjfummtf
9        PROJECT AREA HYDROGEOLOGICAL ASSESSMENT
9. f Hydn^tvbj^a/ Car/;
9.1.1          Overview
9. L2 River deposits / granular alluvium
9.13 Yenisei / cohesive aUuviurn
9 1,4 Colluvial / residual ieworkrd Mill deposits
9.13 Basalt
9.1.6    Tuff
9.1.7     Dolecte
9.1.8     Basement Rock
9.2             rfqmJtrTyptj1
9, J 
Prvprrtiff and PmdM.fhnty
9.4             CnwfithMiter Kjdwfge
9. > GrvMndwater DiSi i\rrpf
9.6      Cj row dwaltr I -Aw IlimriM 9- 7    (inHittdwaftr Quality
9.8      C/vundvrarer Pafenfialjbr IF^/rr
72 72
73
73
73
73 75 78
80
80
81
81
SI
81
81
84
84
85
85
89
89
91
PZ 9J
95
95
95
95
95
95
96 9b
96
96
98 98 99
10/ 102 103 106E.'frptw w im^f>'”f *2             Pn’!rfJ
9, ? M hp** f//m>rtwi on GnwMfotffr Syto*
io  COMMAND AREA GEOTECHNICAL PARAMETERS
103
102     Tprw/ (Tty
103      VfrttMb
10.4           M/ HroiFff Cfy/Stb
103 1 WAv/ Grry (Jaj/Sdi
10.6           R/f¥f tfiu/ Sinam OtpMlf
!0.7 Gfiow
70 U'wJ'/wrtf' Rosaff
10.9
11     DAM SITE AREA GEOTECHNICAL PARAMETERS J/J
11.2           Summary Laboratory Test Tajulto
113 Top Soil
11.4           Coht/in AOunum
113 (jrarwiar Al/uitum / R/itr Tnrwt D/paritr
11.6    Cvihtnm/Rr ndual Soil
11.7     Trf&fak
1IJ fatfat/ Htmrk
11.9 Dcirnif Infmiw
12     GEOTECHNICAL DESIGN ISSUES
123 lutooduefton
12.2           Dam Type
123 Dm I oxndaOe rtf
123.1   Geological Variability
123-2 Removal of Superficial Matrculs 123 Dam SOr Lo&Jtrvrtion M.climate A jjer/menf
12.4.1  Rockfill
12.4.2  Annourstanc 12.43 Sind and Gravel
12.4 4 Clay
12.5     / ircW&wrj?/ Jhpr Sfabiirfy
12.6  Dam 1-oumiafion J na/meitf fit 'atrr t/ghfrufi)
12. Spi/foay E.\i-4jj«rwff cjirJ DefrjtK
127.1   Saddle Spillway (Ophons A lo C) 127.2   Abutment Slope Spillway (Options D)
/23 RjJ/rHwr
JZ# Dtf/w Ji/f           R/jmoir Slope Siabilih 12.0. 1 Dam Site Slopes
12.9 2 Reservoir slopes
1230 Srifnwity
TVT'tdtni/ Dtmncrurir H/pMu rfEMpia, MimJ/ry ttf IFetfr ru E#zrp
HaW*?^ A>Ar
nrf
JVwvir
/2. f I Cana/ CotffFwrfion o* Shrinking and Snn/hng Cirri fl rrrirtfZfJ 12. f2 Cana/ Hfxbankmtnt Eartbfi//Midrfufr
12.f 3 Command slrrJ Rflikfi//Ma/ffltilr J 2. t4 Cana/ Uakage ana' Utting
13  CONCLUSIONS AND RECOMMENDATIONS
/ J. f Ctne/rumi — Gwtyy and Gfoftrhnkf 13,2           Cnnrinmni -1 Ijdrvgntogf
fJJ Rnvntjntndariom
14      REFERENCES
vM
drawings •       *? Msuf m ,iu5
—-
I L'B/FS/GEO/F/Ol
t  UB/FS/GEQ/E/02
J Dam Site Explore I Location Plan
Command Area Exploratory Hole Location Plan
UB/FS/GEO/F/03____ :
• foibded m Album of l)»W. -u
Dam Site Geological Summary Plan___________
MAPS’* i reduced to A4 sire in thw report)--------------------- .---------------------------------------
UB/FS/GEO/tW/01
UB/FS/GF.O/10/02
I     UB/FS/GEO/ipO/03
, UB/FS/GF.Q/2/04
•• Included tn Mips Album, Al
ANNEXES
Gcologj^Map of Command Area 
Geology Map of Dam Site and Rose noir Area  
I Ivdrujjcologkal Map ofCommand Area Geological Long Section of Upper Belt* Dam Axis. 
1 PART 1 OF 3 (BOUND WITH MAIN SUPPLEMENTARY REPORT) ANNEXA jl          ’ROJECT AREA PHOTOGRAPHS
ANNEX B            (COMMAND AREA GEOTECHNICAL PARAMETER PLOTS
. ANNEX C: fl
TAM   SITE   GEOLOGICAL   MAPPING   OUTCROP   AND   JOINT !  OBSERVATION P( )INTS
1 ANNEX D: PRELIMINARY SEISMIC HAZARD ASSESSMENT
[PART2OF3 
__ _
ANNEX E
L
DAM   SITE   DRILLING   INVESTIGATION   FINAL   FACTUAL   REPORT,   ADDIS GEOSYSTEMS CO LTD. J ANGARY 2011 
1
i ANNEX F:           DAM SHE SLAKE DURABILITY PHOTOGRAPHS
1 ANNEX G.          DAM SITE GEOPHYSICAL SURVEY FINAL REPORT, JANUARY 2011 lANNEX Hl: '        TRIAL PIT LOGS. DAM SITE AREA
| ANNEX H.2:        TRIAL PIT PI IOTOGRAPIIS: DAM SITE AREA
___  _
___
J
ANNEX H 3
PART 3 OF 3
ANNEX1
ANNEX):
1 -AB TEST RESULTS EROM DAM SITE TRI.AL PITS
RIGHT BANK SLAIN CANAL DRJ1J.ING INVESTIGATION FACTUAL REPORT ADDIS GEOSYSTEMS CO LTD. DECEMBER 2009
RIGHT BANK VCEIR GEOPHYSICAL SURVEY REPORT
ANNEX K.I.      TRIAL PH .AND HAND AUGER LOGS: COMMAND AREA
ANNEX K.2: /TRIAL PH AND HAND AUGER PHOTOGRAPHS: COMMAND ARFA
•ANNEX LI         LAB TEST RESULTS FROM TRIAL PITS STAGE 1 COMMAND .AREA ANNEX L2        LAB TEST RESULTS FROM IRIAI. PITS: STAGE 3 COMMAND AREA ANNEX L3        LAB TEST RESULTS from trial PH'S: STAGE 4 & 5 COMMAND AREA ANNEX M          SOIL HYDRAUIJC CONDUCTIVITY MEASUREMENTS
1  ANNEXN
1 GROUNDWATER QUA1JTY TEST RESULTS
ANNEX O:       /PREVIOUS GROUNDWATER WEIL COMPLETION REPORTS
ANNl-v p
| GUIDELINES FORTESTING .AND MONITORING GROUNDWATER WFJJ5tv.wn// Pr/wwrun.- Hspurt. ifEth*** Aluufty eflTjftr c* Efifty
Il/hifwi Ntit
LIST OF FIGURES
Drjtttaft
Figure 1-1; Location of Upper Beks Command Area, \Xeir Site and Dam Sire
mH'
3
Figure 1 2: Rivers & Topography of Scheme Area......................................................... ...... —................ .  ...................................
Figure 1-3: Stage Development Areas...»................. ....... .............. -............. -...............—~........... — ..............................................
Figure 2-1: Geology of the Beks Area (from BCEOM, 1999)............................... . .............. ...  ..... .............................
Figure 3-1: Dam Site Exploratory Hole Ixx*ation Plan............................................................ -................................... ................
Figure 3-2 Command Area Exploratory I lok Location Plan.............................. .... ............................................. ....... ............... 19
Figure 3-3;
Figure 3 -I;
Figure 3-5:
Figure 3  6.
Figure 3 ■*:
Dam Site Geological Summary Plan.........................................................................................................  ...............
Geology Map of Command Area...................... ~—-.............. *.......-......... —......... **............................................
Geology Map of Dam Site and Reservoir Area............................................. ........ —...........•........ -.......... *........— -3
Approximate Locations of Four Potential Dam Sites........................... -................................................... •*.......... & Borehole and Tnal Pit Locations Relative to the Outline Dam Design (+1,427m option) — 34
Figure 3-8 Schematic plan of geophysical lines relative to borehole positions.. ..........................................................................3
Figure 4-1 Regional Geological Map (extract from Geological Map of Ethiopia, 1996)................................................... ..  43
Figure 5-1      Geological l ong Section of Dam Axis
..............................................    ».-53
Figure 5-2;     Resistivity      section Line 1. along the dam axis, view looking upstream..........................................................  56
Figure 5 3; Resistivity section Line 2, perpendicular to dam axis along bottom of valley................................................... ...... 57
Figure 5-4:     Resistivity     section Tanc 3, along saddle            ridge (across spillway channel)...........................................   58
Figure 5 5:     Resistivity      section Line 4. downstream side of saddle ridge (along spillway channel) .................................  58
Figure 6-1; Chanko river (top kft), View of Dercbay plain (top right), cropping upstream of Fcndika
(bottom left) and on Werk Meda plain (bottom right)............................................ . ..............»..... —...............................66
Figure 7-1 Specific Capacity* (1/s/m) of aquifers in the Tana Beks region.................................... ,................................ 79
Figure 9-1: Hydrogeological Map of Command Area.............. ............................... ........................................... .................... .  97
LIST OF TAB LES
Tabk 2-1: 1:2,000.000 scale geological maps and memoirs of Ethiopia................................................................... ................ . 11
Table 2-2: 1:250,000 scale geological map index of the Nile Basin area....................................................................................... 12
Tabic 3-1: Ground Investigation Works in the Command Irrigation .Area............................................. .................................. 24
Table 3-2: Summary of Command Area Ground Investigation Dates............................ ............................................................ 25
Table 3-3: Summan of command area drilling and sampling.................................................................................................                j i                                     26
Table 3-4: Summary of command area geophysical i resistivity)                surveys..................................................................  26
.
Table 3-5: Summary of tnal pits, augen and sampling for each
irrigation development stage............................... 27
Table 3-6: Command area tnal pit. auger and sampling details.................................................................................................  27
Tabk 3-7: Summary of laboratory resting on samples
Table 3-8: Summary of laboratory testing on samples
from drilling investigations       in the Command   Area30 from trial pits and hand augen       in the Command
Area ..... .................... .................................. ....... ................................. ....... ...... ......................... .................. ....................... 31
Tabk 3-9: Summan of potential dam sites (assuming 
!75Mm' gross storage).................................... ....................... 32
Tabk 3-10: Ground investigation works in the Dam Site and Reservoir Area....................... ...................................................  35
Table 3-11: Borehole details at the Upper Bdrs Dam Site................................ . ...........................................................................
I able 3-12; Geophysical survey lines at the L'pper Belts Dam Site ...,.............................. .......................................... ..... .. 37
Tabk 3 13 Trial pits at the Upper Belts Dam Site....................................................... ... .................................. ............................  38
Table 3-14: Annex Contcnrs for Ground Investigation Results.....................................................  ........... ....................... .. ...... 33
Tabk 4-1: Nile Basin Geological Stratigraphy ........................... ....... ....................... . ...................... ..........................................  4t
Tabic 5-1 Geological Units at the Dam Site and Reservoir Area.............................................. ................................................... 54
table 5-2 Geotechnical units found in boreholes and trial pits in ihe Dam Site Area...................................... .......................... 55
vii_ 
E^u. V>
r bsupii. MMr) tt » •«"’ r i:v^
P ’’**'P™'''
Tible M; T«H Oc—’ “ f—1 *“ E*P'“'“T "7 ---------------------- -----
I* « 'Ll 0—« » «—* •'■“ Ejpk”7 ...................................... .......
T.bk    6    J:    W    »'™    SJV    °*»M       “    Cl“mm”d      Ara      E'P,on">n'    "    ■■-
Tible 64 YcBow/Grey Chy/Silt exploratory hok locations..........................................
Table 6-5: Weathered Basalt exploratory hole locations.................. -.....................
Table 7-1 Aquifer Types and Productivity m Abbiv Basin (from BCEOM 199R and Hydrogeological
Map of Ethiopia. 1988)—.............................. ........................... -............................................................................
Table 7-2: Classes of Yield and Specific Capacity V alues '"BCEOM)............. ........................................ ............. -.“6
Table 7-3: Estimated Permeabilities (m/dayj for Aquifer Productivity Class (BCEOM).........................................76
Table 7 4: Hydrodynamic Properties of Geological Formations (BCEOM). ............................................ ................/6
Table 7-5: BCEOM lnfiknuon Coefficients.........—..................-....................-...................................................... ......77
Table 7-6: Yield and specific opacity values of major aquifers................................................................................... 80
Table 8-1 Pwzometnc groundwater level monitoring data at dam site boreholes.........................  .................. ........ 82
Tabic 8-2: Groundwater Piezometer Details tn the Dam Site Area.................................................. ...........-....... ...... 84
Table 8-3: Groundwater encountered in the exploratory holes................... .............................................................. 85
Table 8 4: Data inventory for surveyed groundwater wells............... ..................... -....................... ................ .......... 87
Table 8-5: Main sources of potable water in project area kebeks.............................................. ....... ........ -..........—89
Table 8-6. Mam sources of potable water for surveyed households............... -............... ...........................................89
7
Table 8-  Population Projection for the Project Area..........................................................-............ ......................... 92
Table 8-8: Potable water supply demand projections for project area............................................................. -...... 93
Table 9-1: Piwi Station Monthly Rainfall Data (mm)~....~............................................ ...... ....... . ................... ......... 99
Table 9-2: Long term average area) rainfall (mm).......... ..................... ....................................... .....................
Table 9-3. long term average flows (m'/s)................ —................................. ______ ............... —-...... ..... --..........-1^2
1 able 9 4 WHO Guidelines for Drinking Water Quality (1984)..... .......... „........................................ -................
Table 9-5: Ethiopian Water Quality Guideline (after Continental Consults, 2002)...... ................-.....................
Fable 9-6; Water quality test result and WHO guideline and Ethiopian guidelines . .... ................ ...................B^
lable 10-1 Command Area Parameter Plots in Annex B........................ ~................ . .......-............ -................ -...109
7 able 10-2: Natural Moisture Content and Atterburg limit Results ........................................... .......... ............. I 1®
Table 10-3 Command .Area Geotechnical Parameters...... ............ ......... .......... ................. _................................ 111
7 able 11-1: Soil Sampling Details from Upper Beles Boreholes.................................................. .... 7 able 11 -2: Rock Sampling Details from Upper Beles Boreholes and Proposed Quarry Site Table 11-3 Soil laboratory test results from borehole samples .......................
I able 11-4. Soil laboratory test results from trial pit samples...... .................
1 able 11-5. Rock laboratory test results from borebole samples..................
Tabk 11 6: Rock laboratory test results from quarry samples...... ................
Table H -7 Falling and (lonstant 1 lead Permeability Test Results....... .......
Tabic ll-R Lugeon Test Results . ...... ......................................................... ..
.120
.120
.121
123
.124
.124
.125
126
1 ablr 12-1 Summan of Potential Basalt Quarry Locations.......... ..............
-............. _............ 132
1 abk 13 i Recommcndrd Specific Issues to be addressed by ground investigation for Detailed Design
............. ............ ...................  ................................................................................................  1
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ABBREVIATIONS AND ACRONYMS
ADSWE
AGCL
ASTM
B
BH
BS
D
DEM
E
EIGS
EMA
GPS
GR
GW
Ha
HA
HEP
Amhara Design A Supervision Works Enterprise Addis Geoiystems Company Ltd
American Society far Testing and Materials Bulk disturbed soil sample
Borehole
British Standard
Small disturbed soil sample
Digital Elevation Model
East
Ethiopian Institute of Geological Surveys Ethiopian Mapping Agency
Global Positioning System Grid Reference
Ground Water Well
Hectares
Hand Auger
11 ydro Electric Power
HH
ISRM
km
KPa
E louse hold
International Society of Rock Mechanics Kilometres
Kilopascal
m
mml
mbgl
Meters
Meters above sea level Meters below ground level
.Mm’
MPa
N
ME
NMG
Million meters tubed
Megapascal
North
North east
Natural Moisture Content
NW
CMC
North west
Optimum Moisture Content
PT
S SDA
SE
SPT
SR
SW
SWL
TP
TWL
U
ucs
UTM
Plasticin Index
South
Stage Development Aiea
South cast
Standard Penetration Test Supplementin' Report
South west
Static Water Level
Trial Pic
Tup Waler Level (of a storage reservoir) Undisturbed soil simple
LI neon fined Compressive Strength Universal Transverse Mercator
LXtyr* * 'HU**
E rtrtn* .Vi* !t&tM *d Drvt^t P^rf
W
WCE OUSE
West
Water Works Construction Enterprise
Water Works Design and Supervision Enterprise
xofEtintoi*. Mr vim tfW j' frr c** Hjwji
Njt>              jwrf Pmwjgr Pnp*i
1 INTRODUCTION AND SITE DESCRIPTION
/. /              Obfecffves ttod Con ten t of thijr Report
This supplementary report provides rhe results ofground investigations and in lnterprelation ol the geology, hydrogeology and geotechnical properties of the soils and rucks in chr Upper Beks project area to inform feasibility stage engineering designs llic report considers two areas of Upper licks; iT! the proposed irrigation command area, pnmnnlv along the approximate alignment of the mam canals; and (it) at the site of i proposed dam and reservoir for an irrigation storage reservoir in rhe upper catchment {Figure 1-1}-
Geological, hydrogeological and geotechnical investigation and assessment are required to assess, among other issues, rhe following:
•       Dam site foundation bearing capacity, construetjem type and dope stability;
•      Dam site and reservoir water tightness;
• 
Reservoir area slope stability;
• 
Location and volume of construction materials;
• 
Diversion weir site foundation renditions;
• 
Irrigation canal and irrigation structures fotindations and stability.
•      Existing groundwater users; and
•       Potential for groundwater exploitation to support resettlement in the command area.
The ground investigation works comprised geological mapping, trial pitting, boreholes, geotechnical laboratory testing, geophysical surveys, undertaken between January and February 2010 in rhe command area, and between April and November 2010 a! the proposed dam site. Hydrogeological surveys also included walkover surveys, interviews and data gathering ar local VC’oreda offices and villages *l*his report includes derails of the work that has been completed anil I he methods used. Factual data arc provided in annexes to this report.
Interpretations of geology, hydrogeology and geotechnical properties arc based mainJv on the rrsulrs of the ground investigation work, but also make reference to background information from previous reports and published maps and papers Interpretations also make use of data collected and reported under Other rkments of the project, for example Soil Survey work (supplementary report SR-02A) and socio economic surveys (SR-03A) for settlement groundwater usage Specific geotechnical assessments applicable to engineering design*, arc also reported in the Supplementin’ Reports for Engineering SR CM A (Irrigation and Drainage) and SR 1)4 B (Storage Dam)
Brief descriptions of the project area and of the proposed engineering components of die scheme arc included in this Introductory Chapter. Chapter 2 reviews previous work anil Chapter 3 describes the scope of the feasibility stage ground investigation works. 1 hr regional geolog)- is summarised in Chapter 4, and descriptions of the geology of the dim site area and irrigation command area are provided tn Chapter 5 and Chapter 6 res pec lively.
1 he hydrogeology of the region and project area is described in Chapters 7, 8 and 9. An assessment of die geotechnical properties of the main soil and rock units in the Command Area and Dam Sire Area is made in Chapters ID and 11 The key geolechmrxl issues affecting
l B f»4 SRO1G Cieurrdi Part 1 (!)
H May. 11ot£wrre¥ doip, fo: ik comnund irr. tnd dim site area arc discussed in Chapter 12 |n
Q.ptef U concluwons art dra^. and recommendations arc made
\nnn« are prodded it the end of this report These include photographs, geotechnical panmeter plot', pound mvestipUon factual reports for trials pits and boreholes (logs, m Sltu tntmp monitoring and laboratory test results), geophysical survey reports, and hydrogcologd data obtuned from W oreda offices
The feasibility stage engineering designs arc based on our experience of the design of dam and imginon structures and take into account the interpreted geotechnical and hydrogeological cnnditxxis from the feasibility stage ground investigation. Il is important to recognise that confirmation of geotechnical assessments (and particularly stability and material suitability) will be required at detailed design stage, along with more detailed structure and site specific ground wivesagaoons and geotechnical and hydrogeological interpretation.
Project Locaoon and Topographic Setting
The Upper Beles project is located in the Ikies nver sub-basin in the west central portion of the Abbav nver basin, southwest of Lake Tana (Figure 1-1 and Figure 1-2). The main town in the Upper Beles command area is Pawi (Alemu) which is located 606 km west of Addis Ababa Other towns include Werk Modi and Fcndika Qawi.) The main Beles ever originates at the foot of the escarpment which divides it from Lake Tana.
The project irca is downstream of the Tana-Beles Hydroelectric Power (HEP) scheme that was commissioned on 14* May 2010. ’rhe 1IEP scheme transfers water from Lake Tana through about 19 km of tunnel to an outlet in the upper reach of the Enat Belts River upstream ot the first of three wan constructed to control (maintain) nver bed levels downstream of the outlet following commissioning of the HEP station.
The elevations of the three won and footbridges of the Tana-Beles 11F.P scheme arc as follows:
•     War I with crest at 1440.0 mail.
•     Footbndgc with deck at 1450 0 mail;
•     Weir 2 with crest it 1414 50 masl. with footbndgc with deck at 1424.55 masl; and
•     Wen 5 with crest at 1405 50 masl, with footbndgc with deck at 1411 55 masl
The proposed dam site is located about 7.5 km downstream and southwest of the hsi (third) weu. where die Beles flows through hilly and rock) terrain, often in a shallow gorgr. at an elevation of between about 1300 ind 1500 masl The river bed elevation at the proposed dam site n about 1328 mail Under normal Bow conditions, the Belts nver vanes between
meandering through wide sand and gravel bars, to being incised in shallow rock or river terrace
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The full supply level of the proposed reservoir area for the high (large) dam option is about + 1,420 masl. submerging the lowest weir (Nr 3) and footbndge. and reaching to the second weir. ITie smaller dam option full supply level is about + 1,360 masl and u-dl not reach any of the weirs. I he left bank canal is proposed io have an initial elevation of about + 1,355 mask The location plan of the dam site area is shown on Drawing UB/FS/GEO/F/OI
Below the dam site the river continues tn flow through hilly terrain for about 12 km before emerging onto a broad NE-SW orientated undulating plain which forms the proposed irrigation command area with land elevations mostly lying between about 1000 masl and 1200 masL The plain is flanked by a steep escarpment to the cast (left side of the scheme area), and by lower hills forming a groundwafer divide between the scheme and the Hyma (Upper Dindir) valley to the west (Figure 1-2) The proposed Upper Belts irrigation command area mainly comprises the upper catchments of lhe Main fF.nat) Beles and the Gilgel Abat Beles nvers and their tributaries
At the upstream end of the plain a diversion weir and the head of the right bank main canal are under construction by the Amhara Water Works Construction Enterprise (WWCE) where the over bed level is about +1,240 masl This is about 26 km NE of the town of Jawi / Fendika.
J awn is a newly established Woreda with Fendika being the capital. The plain is flanked by a steep escarpment to the east (left side of the command area) and lower hills forming a groundwater divide from the Dindir valley to rhe west (right side).
The proposed nght bank Main Canal passes through undulating terrain tn the area between rhe w’cir site and Fendika Beyond Fendika the canal FSL drops from about *1.239 to +1.133 masl into the flatter, undulating Derebav plain to rhe southwest. The proposed left bank Main Canal passes through mountainous terrain in die northern area becoming hilly towards Wcrk Mcda and more undulating plain along the southern section.
Dur the large size of Upper Belts with highly varying physical (and social / population) characteristics, the scheme is divided up into five Stage Development Areas (SDA’s) according to physical (eg nver) boundaries, sec Figure 1-3. The five SDA’s arc broadly prioritised as follows:
•      Stage I
• Stage 11
• Stage Ill
• Stage FV
•      Stage V
Upper Bries right bank upper and middle zones; Upper Hyma (Dindir) (outside of feasibility shady project area); Upper Beles nght bank, lower zone;
Upper Beles left bank, upper and middle zones Upper Beles left bank, lower zone
Note Stage II for Upper Myrna "Dindir) docs nor form part of lhe feasibility study area, bur is included as irrigation development of this area is envisaged by diverting water from the Main canal at Fendika The net irrigable irea for Stage II is likely to be about 19,184) ha.
Some of the SDA’s were further divided up into difference sub stages II is envisaged that project implementation will be phased around these SDA’s, starting on lhe right bank and proceeding to the let! bank.
LB F4SH04C Gmtrch Pir I (1)
5
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IJ Larrtf Use *nd Accffl
The dam site and reservoir area is partly used for fanrung, although much of the area is *.crub or forest. Access to the dam site area is by driving to the south western downstream end of the Tana-Beles HEP construction road, where there is a footbridge across the Bclrs river From here there is an approximately 2.5 to 3.5 hr walk to reach the dam site, following footpaths
along the casr or west side uf rhe Re les nver valley.
An alternative route is by walking a similar distance down the escarpment in a north west direction from the town of Yismah, which reaches the left bank of the Belts near u> the proposed dam site.
Bun ng dam site ground investigation works, die lana-Belrs HEP commenced production* 1 causing a large increase in flows on the Bries River and making crossing the river at rhe dam site area impossible The only way to safely cross the river is to use the lowest weir / iootbndge of rhe Tina Bclc* HEP project. This meant dial during drilling investigations. to complete boreholes on both dam abutments, equipment had to be dismantled and earned back to the
tool bridge and thru down the opposite bank.
The land in thr command area is currently partly used for farming, growing mainly cereal crops and as grazing land. Hie remainder of the command area is largely forest land or grass land. Forest land is also present on the steeper slopes and on rop of hills lo the north of The command area. Hie lack of farming in these arris is likely due to steeper slopes and thinner
soils formed on bedrock
Access to the command area is by various gravel/earthen roads leading from the num Addis Ababa - Bihir Dir road through Gilgrl Belts just to the south of the command area.
hl              PropoiseJ Construction
The main objectives of the ground investigation were to obtain geological and geotechnical data I bar are appropriate for feasibility stage design of rhe main engineering elements of the irrigation scheme The data collected will allow interpretation o£ (T) a ground model for the area defining the type and location of the key geological units; and (ii) geotechnical parameters
At rhe rime of die ground invesugaoon, proposed engineering works for the Upper Bdes irrigated agriculture development scheme were expectrd to comprise the following
components:
• A storage dam located across the Upper Bdes nver at about grid reference 261I90E,
1293“** ON with lrriganon off-take supplying the left main canal There are several options2 for rhe gross storage and hence dam size but for the purpose of the ground investigation a reservoir with ar least 175 Mm’ storage volume requiring a dam nf about
1
The HIT <mtLon cMmiisiinncd o® M *  May 20W
11
1 Dam include :i' < Jpiion A/H with FSJ. of ],4_'S masl (groM Munge 2 V) Mm3;r fa) Optum C FSL of 1,420 mail gross
iroragc 3’8 Mm3!, and (iu) (Jpnnci J with FSL of 1,360 m»’l storage 21) Mm3). Kcicr Fn^nccnnf;; Jhm« 'uppk-rnentarj' irpnct
UHF4 SttlMC Grgich Pur I (1)
7
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60 to 70 m height (+1.330 to+1.400 masf; and a crest length of about 1.1 km is
. A diversion weir for the nght main canal across the Belts river at about grid reference
’’4787OE 12899^0N where the bed level is about +1,230 masl comprising a weir micro^am\ head regulator and sand trap The diversion weir is currently (February
2011) under construction by the Amhara Water Works Construction Enterprise
(AWWCE).
. Irrigation system deseloped for about 64.000 ha (excluding Ilyma) and about R3.00C hr (including Hyma)’.
•      Approximately 30km of nght bank main canal from the diversion weir rojawi
(l endika). current}}- under construction by AWWCE (proposed to be lined / provided with geo membrane)
•     Approximately 70km of nght bank num canal from Jawi (Fendika) to the tail of the command area (total length of nght hank main canal aboui 100.3 km), largely lined
with nusi concrete placed over a geo-membrane.
•      Approximately 131.9 km of lined left hank main canal from the dam site to southwest ofWerk Modi, including cutting through a saddle al GR 243400li 1273100N requiring an estimated 10m of rock excavation.
•      Balancing reservoirs along the main canals to ease operation and reduce operational
losses
•      Night storage reservoirs at / near die head of each secondin' canal
•      Regulating and conveyance structures along canals including drops, aqueducts and inverted siphons.
•      For some stage developmeni areas alternative pressure (sprinkler) irrigation options arc likely to be designed and costed.
•      Surface drainage systems development composing drainage channels and associated structures.
•      l-lood protection reservations/ corridors along existing rivers and streams that pass through the command area with bunds where required.
•      All-weather gravel roads.
•      I-and development including terraang of slopcs>3° 0
• Soil and water conservation measures, particularly in the areas not irrigated but within the gross command area. ind also in the reservoir catchment area
The ground investigation has been designed to aaaeu the various ground conditions likely to be ent ountered, combined with selective investigation of possible locations for lhe above engineering works The investigation is intended to assist feasibility stage designs Additional
survryj in nut
pan nf rhrs fcnibdin tludy and thr I lyma imgahlc arn mar chunge cunpidcribly.
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8
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Eff’Mpur* Nik Irr^fraif jnrJ Drar*atf Prnpil
The key geotechnicid issues for the Upper Beks project* identified by this assessment, are.
•      Depth to bedrock;
■ Foundjtton design in day sods (Le. swelling, settlement, bearing capacity');
•      Suitability of sods for earthworks / availability of suitable construction materials (ie. stability and erosion, induding piping);
•      Need for lined canals, and
•      Dam specific geotechnical issues such as presence of active faults, permeability* and seepage and requirement* for foundation treatment, availability' of construction
materials.
FH M SR.LHCI Gcotrch Part 1 (1)
9
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2         REVIEW OF EXISTING GEOLOGICAL INFORMATION z/         Summan'
There ire no previous ground investigation Jara available for tbr project area, although
engineering uiv«tigauoro have been completed at the Tinl-Bdcs ILEP scheme approximately
18 km northeast of the dam site Published geological and hydrogeological mapping is only available ar small scale (1:^000.000) for the whole of Ethiopia
The area has been studied by; ® "jepwn DH. Blue Nile River Basin Investigation. Lake Tana
sub - basin, I960”, Blue Nile River Bastn F.thjo - US cooperation. 1963; (ii) the Ethiopian Institute of Geological Survey* (EIGS) mineral exploration team for mineral exploration 1996;
and (tii) BCEOM in association with BRGM and ISI- as part of the Abbay River Basin
Integrated Development Master Plan Project. 1998 The latter produced an unpublished geological reconnaissance map of the Abbay River Basin (BCEOM, 1999). The findings of the
various studies are tntti manned beksw and description* of the regional and site geology arc
provided in the following chap re is.
A preliminary assessment was completed in advance of planning the ground investigation using
ihe previous, studies described in this Chapter. In summary, the project area is shown from published geological mapping to compose: basemeni meta volcano - sedimentary rocks, post
tectonic granite, Tertian volcanic rocks of the Ashangi and Tarmaber Fm, plateau basalt and Alluvium. Ihe major structural features affecting the lithologic units in the area are shown to
1 rend NF - SW and NW - SE
Z 2           Pubtithed GroJogfcjd Afaps and fieporf*
Available  geological  map  coverage  of the Nile Ba  mu  project area  was determined from  visits Io the library of rhe EIGS, Ministry of Mine* and Energy in Addis Ababa in April 2009 and July
2010 Key maps air summarised in Table 2-1.
Table 2-1: lt2 000,000 scale geological map* and memoirs of Ethiopia
w
Scale
Title and Dale
Comm ru ts
1:2,000,000
Geological Map of Ethiopia, 1" Edition, 1973, Ethiopian Imttlule nf Gen logical Surveys (EIGS)
Superseded   by   second   ediuan   below   Use*   older Mra'tigraphic scheme with |ejk unit s.
1:2,000.000
Geological Map of Ethiopia, 2nd Edition, 1996, EIGS (ref 1)
Small scale covering  whole country, not derailed for titc specific ground condlmams., but provides regional stratigraphic and structural context.
1:2,000.000
Hydrogeological Map of Ethiopia, 1988, EIGS (ref 2)
Small scale. comment as above. Includes inset mapt of topography and rainfall, water resource regions and recharge discharge condinons.
Report
E’jplanaUon of the Geological Map
nd
of Ethiopia, 2    Edition. 1999,
EIGS (ref 3)
To accompany map, due io map scale general descriptions only,78 pages. Useful lit! of
references.
Report
Explanation oi the Hvdrngcological Map of Ethiopia. 1985, EIGS (ref 4)
To accompany map, due tn map scale general descriptions only. 11 pages Useful List of
references
UR I-4 SR04C Gtoicch Purr I (])
11
14 May 11P/wwr*.
A5i M«* **
****
2 2 I         1:2.000,000 wk G"bff*l Maps of Ethiopia
Tlie only published geological maps available for the project area are 1 2,000,000 scale map, geology and hydrogeology) that cover the whole country I able 2-1). These maps do not provide a detailed definition of the local geology. The 1:2.000,000 scale geological map of Ethiopia (ref 1) » the predominant source of regional geological information and is described m Section 4.2
2.2.2        1:250,000 wk Rejponai Grohfical Maps
The smallest scale published geological map senes available from the EIGS are at 1:250,000
-scale, and follow the same areas used for the topographic map sheets produced by the Ethiopian Mapping Agency (EMA).
There arc nineteen topographic sheets cuvrring the Nile Basin area, shown in I able 2-2 Of die 19 areas, published 1:250.000 scale geological maps arc available for nine areas ' shown as shaded in Table 2-2). Upper Bclcs is located on EMA 1:250,000 scale sheet NC-3 1 (Bahir Dai). j\ published geological map has not been produced for this sheet.
Table 2-2: 1:250,000 scale geological map index of the Nile Basin area
ND 36 16 WES l ol GOND1R
ND 37-13
ND r 14
G< )NDER (’MP)
Y1FAG
NG 36 4
NC 37-1
NG 37 2
ABU RAMLA
BAHIR BAR (-UB)
DEBRE TABOR
N’t 373
DESK
NC36 8
NC -37 5 
NC-37 6
BURE
DEBRE MARKOS
NC-37 ”
VC ERE II U
NG 36-12
NC 37-9
NC-37-10
NC 37-11.
GJMB1
NEKEMTE
ADDIS ABABA
1
DEBRE B1RHAN j
NC 36 16
NC-37 13
NC-37 14
GORI
ARJO (-ND)
AK’AK'I BESEICA
Notes 1
2
NB 3? I
1IMA
Burd on EMA 1:250.000 *ealr topographx map sheets
Gcnlugnal map. avuhhJc frnm EIGS .re drawn ,h»ded. Geolojncd map; *rr not avmbl*
tor the un-sliaded Areas.
3 ’h7o fW VXbai'n p,0KCT "*■* i,r indio,,ed bv *"
- Mcgcch Pump; LT = Upper Beks.
1
ND = Neceto Dim. Mp
*
I H 1-4 SRl4( Groh ch Part 1 (!)
12
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EVAwyw* A7*            inwfP«mgf P^ht
2. J           Abbay Sa/wi Afasfefp/aftt JJGEOM, 19^8
Reconnaissance level geological mapping of rhe Nile (Abbay) basin was completed at L250,000
scale for the Abbay River Basin Integrated Development Master Plan Project (ret 5). A digital geological map of rhe project area was completed using GIS and prepared from the following
sources:
•      Lands at TM satellite imigcry data;
•      /Ml the geological documents available concerning the master plan study area, especially published maps and unpublished draft-maps provided by EIGS; and
•      Several missions for field checking by car or aircraft
The mapping identifies the main geological units, photo-lineaments, volcanoes and volcanic
plugs- An unpuhhshcd digital extract from this map is shown at A3 size in Figure 2-1
In the Bries project area the map shows the following:
•      At the dam site bedrock is partially T1B2 (Tarmaber Basalt) and partially TA AB
(Amba Alba Basalt);
•      7*he reservoir area is shown as predominantly TTB2 (Tarmaber Basalt),
•     Just downstream of die dam and covering the escarpments on the edges of the command area is TASB (Ashangi Basalt);
•      Most of rhe command area is shown to be underlain by die older and lower lying PULC (Undifferentiated Lower Complex);
•      At The southern end of rhe command area is an outcrop of PGT2 (post tectonic
granite) and to the south an extensive area shown as PlTC (Tsalict and Tambien
Group clastics);
•      In the main over channels and low lying area of the commanil area, QALL (alluvium)
is shown to overlie bedrock; and
•      Faults / lineaments are shown trending N-S and NE-SW in the dam site area
Fieldwork in the project area has identified that the level of detail of the BCEOM
reconnaissance geological mapping is not sufficient for engineering studies and ihcre are misinterpretations of satellite imagery, probably due co a limited amount of ground-(milling,
1’he  master  plan  study  also  provides  some  background  on  the  regional  and  structural  geology  of rhe Nile Basin (ref 5) The report ales the following geological documents:
•      Geological map of East Africa (from G- DimelL - 1943) scale : 1:1 *000*000;
•      Geological map of Blue Nile basin (USBR study 1964) scale : 1 1,000,000;
•      Geological map of Ftluopia and Somalia (from Meria 1973) scale ; 1:2*000,000;
•      Geological map ot I-ake Tana (from Ethiopian Ministry of Mmes - 1973),
•      USBR Land and Water Resources of the Blue Nik basin. Geological Report, 1964;
•      Lahmeyer, Gilgel Abbay Scheme. 1962;
•      Several studies by ACRES Chemoga-Yeda, 1987; Aleltu, 1994; Bin-Kcgi Irrigation Project, 1994);
•      WAPCOS, Preliminary Water Resources Development Master Plan for ETHIOPIA 1990;and
•      Studio Pictrangeli, Tana Beks Project, 1990.
; H i*4 SKlMC GccHeda Pott I (E)
13
14 May-IIFtdfrul Dwntfi; RfftM; ofIlfbupii, Miwtry of Vator d* Eurtg
Efhwpiat Ntlf
and Drarttagt Prvprd
2.4 Recent Water Resource and Irrigation Studies
More recently, a program of water resource assessments and irrigation feasibility studies have been undertaken, particularly for tributaries flowing into Lake Tana. *l'hc regional geology, structure and hydrogeology have been reviewed by SMEC in May 2008 (ref 6) Specific studies that include geological and geotechnical assessment include the Mcgech, Ribb and Koga riven and dam sites.
z
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3          GROUND INVESTIGATION SCOPE AND METHODOLOGY
J. 7           Introduction
Proicct specific ground investigations were undrrtakrn in various phases between November 2009 and October 2010. The works were undertaken by engineering geologists and geotechnical engineers from Halcrnw / GIRD or used drilling, geophysical survey and Laboratory testing subcontractors based in Addis Ababa, The geological, hydrogeological and geotechnical factual data collected during these ground investigation works is included in the annexes to this report. This chapicr summarises the work char has been completed and the methods chat w ere used.
Due to location and access constraints, ground investigation fieldwork was earned separately for the Command Irrigation Area and Dam bite Area, and thew: arc described separately below. Ground invesdgafion locations are shown on drawings UH/FS/GEO/Fni and 02 and to a reduced scale on figure 3*1 (for the dam site area; and f igure 3-2 (for the command irrigation
area).
3.2 Ohfecaveit
The main objectives of the ground invesligation arc to obtain geological and geotechnical data iliat an- appropriair for feasibility stage design of rhe main engineering elements of the scheme. The dara collected will allow intrrpfetation of: (■; a ground model for the area defining the type and location of ihe key geological units; and (IT; geotechnical parameters
Hie key geotechnical issues for [he l*ppc.*r Beles Irrigation Prn|ecl are:
•      Depth to bedrock;
•      Foundation design in soil and rock (Le settlement, beating capacity);
•      Suitability of soils for earthworks / availability of suitable construction materials (i.c. slability, erosion);
•      Nerd for lined canals, and;
•      Dam specific groirchmcal issues such as presence of active faults, permeability and seepage and requirements for foundation treatment.
The ground investigation has been designed to assess the various ground conditions likely to be encountered, combined with selective investigation of proposed locations for the- main engineering works The invcsdgahcri is intended to assist feasibility stage designs. Additional ground investigation is required for full dtiaikd design.
1 H F4 SK(w: Grotceh Part 1 (1)
17
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r1
a-
*              WWMM15 M|nl | **• *•*» *«« «■“■
r himF                T^,J
I 1OTJ                 T    1
1'
-1 1,
■1 1 2
itakrow
iinFfdentl
if Efhepta. Mivitr, if U atr
EthepuM Niit Imratio* mI Dna^t Pnj*f
J J 3. 3. /
Review and Use of Existing Information
Exri/m< Ground Inn/ligation Data
Prior to tins study there was no existing geotechnical ground investigation data, other than la
scale geological mapping, available for rhe project area. Four waler well drilling reports were
available from Woreda offices in the command area that include basic geological logs (Annex
O) as well as data on hand dug wells (see Section 8.4)
X 3.2 
Soil Survey S lapping
In the command area, sod survey mapping results by Halcrow / GIRD were used to assist
geotechnical planning by targeting exploratory’ holes at the main soil types and to mioim
geological mapping. The soil survey investigated generally the upper I to 2m using surface
observations, shallow pits and auger boring. These results arc reported in the Supplementary
Report SR-02A, Soils. Land I’se and Suitability.
3.3.3 Sorto economic snneyr
As part of the feasibility study thematic focus group discussions and agro socio-economic households siin cys were earned out in the Study area. These included an inventory and assessment of rhe potablr water supplies. Details are given in the Supplementary                 SRflV A, and relevant matcnal is included in tins report
3.4 Remote Sensing, Geological Mapping and Topographic Control
Interpretation of satellite imagery has been made to provide a provisional identification of gromoqihological and structural features and to delineate major geological units. Selected fcaturrs were then ground-truthed by follow up geological mapping ar the various stages of the project. Satellite imagery interpretation used recent satellite imagery’ procured under the study (Worldview 0.5m resolution. February 2010).
Mapping and exploratory holes locations and elevations were recorded using .satellite Global Positioning System (GPS), (LTM 37N Adindan datum) Elevations were checked against
I lakrow / GIRD ground truthing topographic surveys and digital elevation model
Geological mapping was undertaken from walkover of selected sites and outcrops combined with extrapolation and interpretation At the tune of the ground investigation, the right bank off-take weir north of Jawi wus already being constructed by ADSWE. Excavations that were underway were inspected
Drawing L’B/F5/GEO/F/03 summarises geological data in the Dam Site .Area and includes satellite imagery Geological maps arc provided as drawing ITJ/FS/GEO/IQO/Ol (Command
.Area) and drawing UB/F’S/GEO/10/02 (Dam Site and Reservoir Area). To a reduced scale these drawings arc reproduced below’ as Figure 3 3, Figure 3 4 and Figure 3-5.
IIR HSRCMC GccHcch Pan I J
20
14-MavJtJtfwfc?afu-               ** iifAr^w. Jjf.'ffZi/J) ' ITj/rr k tMrgi
EfirifWi NfJf foqjftw J/tf Ihj/fMgr Prwtif
Figure 3-3: Dam Site Geological Summary Plan
URI‘4SR04C<kT'trth Pin 1 (I)
21
14-M»v-11Fnkfttl DtJ**rufh‘
Minty 9fWjtrr &
L/Ar«*UuWt Mr Zm^jrr«« and DrMtu^t pr^fM
uWm/DtamftcKtfMr firtwpw.
Nik InTjJfrM      Pf jr»r.«f
tor«*- £iw^FnW  Dr  waft.  fop&i  tfErtoftti.  Miwtn  of  II  jftr  ru   En^i
Eflityia* A7Zr j’wj/'/J’r i&i Drunt^f EntM
J.5           Command laigadon Air a Ground Investigation Work
15./         Summary
Ground invest^ition fieldwork in the Command Area was earned our between November 2009 and February 2010 Tins was followed by laboratory testing completed in April 2010. Summaries of the activities completed and respective dates arc provided in Tabic 3-1 and in Table 3-2. Ground investigation locations in (hr Command Irrigation Area arc shown on Drawing LTB/FS/GEO/F/02 (sec also Figure 3 2) Summary plots of the laboratory test results are given in Annex B. Ibc results are reviewed in Chaplet 10.
1 he boreholes were onginalh proposed tn die location of the diversion weir for rhe right bank main canal off-take Owing to thr lack of access al (he weir site due to the advance excavation and construction works being undertaken by the Amhara Water Works Construction Enterprise, thr proposed boreholes at the weir site were cancelled Instead the excavations were inspected during rhe geological mapping phase, thr results of which were used to confirm die geophysical survey results.
Table 3-1: Ground Investigation Works in the Command Irrigation Area
Activity                               By
Description
Rcconnaissani e Geological Mapping
Haicrow / GIRD Walkover of elected sites and outcrops combined with extrapolation and interpretation using recent satellite imagerv (Worldview 0.5m resolution, February 2010).
(vcophysKal survey
Sub-consultant
(Geophysicist)
llirre rcsistnity survey lines in the vicinity of the proposed sand trap to thr weir structure:
•                    along the axis of the sand trap
•                    two almost perpendicular to the axis of the
sand trap
Borehole* and associated laboratory
testing
Addis Gcosnfems Co. lad (Sub
Contractor)
1
Two cable percussion l>orchole5 with rotary core follow on. BH CBHSR 01 and BH UBBSR 02 in vicinity of the proposed balancing pond, head regulator and an area of num canal cur
Classification, consolidation and sulphate testing.
Trial pitung and hand augrring
Hakrow / GIRD
L
42 hand dug trial pits, two with hand auger follow on, and one hand auger were excavated along the line of the nghr and left bank num canals and within the command area, depth varying between 0.1m and 4.6m. In situ hand shear vane terrs were undertaken in cohesive sods
1laboratory testing of I           W ater W orks Design trial pit and hand auger '     md Supervision
unipies
,
inrerpnse
I uboratorv Service
Sod Uhoratorr tewing generally ui accord«nce with BS1J7' 1975 (ref 7). ChMifiation, compaction, twellmg picture, dupenion, permeability and wjphile.
~i
♦.
l-B M SR(MC (tartech Pan I (1)
V ’>
u May-11Frdtrj.' Dtwair
•fEfhitfia, bfarrtr? nf tTafrr <*- E^nji
T
E rtapr-w A '* In'&w *** 
JWj
Table 3-2: Summary of Command Area Ground Investigation Dates
Stage
Area
Activity
By
Dates
Recon  namance  ger  logical mapping
1 Laictow / GIRD
IS* Nov to ll* Dec 2009
Tnal pitting and hind Mlgrruig
HaJerow / GIRD
IS* Nov lo 11* Dec 2009
I
La Iwal-nry les ting of tnal
pit and hand auger sample*
WWDSE
14* Dec 2009 to 2> Feb
2010 _________________________
Ckuphv-.icaJ umvcv
Sub-cons iilunt geophpidst
27* to 2 8* Nov 2009               ____
Borehole*  and  associated laboraitm- Jesting
.Addis GeosystCfTw Co. Lid (Sub Contractor
h
12*  Dec 2009  to  27« April
2010
RecnnnaLLss i nce gen logical mapping
Hdcrow/GrRD
211* to 28* Dec 2009
ITI
Tnal  pitting  and  hsnd augering
Hikrou / GIRD
20* to ZB* Dec 2009
laboratory  testing  of trial
pit and hand auger larnpJcs
WWDSE
5* Jan 2010 to 22-1 Feb 2010
Reconnjtiisancc geological mapping.
1 lalcrow , GIRD
16* io 26* February 20 W
IV
Tnal pitting  and hand
augrrlng
HaJcrow / GIRD
16** to 26   February 2010
th
I -aboraEorr rcitiug of trial
pit and hind auger samples
WWDSE
26* Feb io 22   April 2010
nd
Rrconnjj&^ancr geological mapping
Hikmw / GLRD
16*  February  2010  to  26* February 22010
V
Tnal pitting  and hand
iiigering
Hikrow / GIRD
16* io 26   February 2010
th
I-ihoraforY  leiting  of  tnal pt! and hand, auger s implies
WWDSF.
26rh Feb to 22nd April 2010
35.2 FMir^ /jrt¥,r/^+ifl»«,r
Originally, boreholes were proposed ai the nght bank canal off-Like weir sue north <>f Jawi and m the area of die geophysical survey. However because die A D S WE were already constructing the weir, the boreholes were moved to locations on, nr adjacent co, the nght side m,im canal near Jawi where a large bifurcation and flow measuring structure may be required to offtake water to Hyma (SDA II). A cross and head regulator is also located in this area, and a balancing reservoir may hr rrquired
Two cable percussive boreholes widi rotary core follow-on, BH UBBSR 0] and BH UBBSR 02, were completed to 13m and 15m depth rrtpecuvdv. The holes also provide general
Ln fun nation on the depth to bedrock beneath superficial deposi the ease of excavation and leakage potential where the
provided in Annex I,
tdual sods, to assess
jjling results arc
t'H F4SHim Geowch I'm I (1)
15
14-M  *ll
ayI-hMVhwWc HrfM. •fUHMpiJ. 
E.'btepiJ* Xihf Imfafiot U*i DrtaWff fr*./
tfV tftr t-F.HV
ln-situ tc<ting composed standard penetration tests (SPT?). Sampling comprised 6mm diameter "50mm long Shelby tube undisturlied (V) ’«"PIes -ind snuU d,5turbcd ,D-> ”">plft
from the SPT spin spoon and nosings. The strata were logged in general accordance with BS5930 (l 999) (ref 8). The boreholes are summarised m Table 3-3.
3 J J         Geopfysw/ (tTJiftint)) Sunw
Three geophysical (resistivity) profile lines were undertaken in the vicinity of a proposed sand trap adjacent to the right bank diversion weir to determine the depth to bedrock and hence case of excavation of the material in this area The locations are summarised in Table 3 4 and shown tn Drawing UB/FS/GEO/F/02 (see also figure 3-2).
Line 1 closely follows the centre line of the sand trap, and is about 300m long. Lincs 2 and 3 run almost perpendicular to Line 1 and are about 120 and 130m long respectively.
Table 3-3: Summary of command area
and sampli
Coordinates
Borehole
Samples
liken
—
Easting
Northing
Final
Depth
(m)
SPT
Objectives
U
D
BII
UBBSR 01
227260
1280603
13
3
5
5
Assess the ground at / near the sites of the proposed bifurcation structure where the main
2268*/)
L’BBSR 02
j canal to I Irma (Area II)
takes off Also provide
general indication of ease
of excavation and leakage
potential where the main
[ canal r in cut
Table 3-4: Summan of command area
1 Profile
Stan Coordinates
End Coordinates
Length
Number
Ea a ting
Northing
Easting | Northinn
(n>)
Line 1
247757
1289988
248016
1290136
300
Line 2
247738
1290076
2477*5
1289949
130
L b“’
247804
1290091
247849
------- I
1289980
—
120 1
Objectives
To determine the depth ru
bedrock and sod profile in
rhe area of rhe nght bank
diversion weir / main canal
sand trap.
J
Ibe objectives of the geophysical survey were to determine
•      The thickness of overburden,
•      The thickness and degree of weathering of die bedrock;
•      The existence of geological structures, eg. faults, fracture zones and dykes The geophysical survey results are presented m Annex J
18 il .SR(MC (icotcch Parr 1(1)Dr
mft ftyridr
.Mitttrfn tf ff ar/*- e Etwgy
u
&Mpt* 
M< * Dm*** r-TF/xr
j f J 
IVm/ Pitti
ng anti Hand .-Ift^rr
Trial pit
 and hand auger investigation! were designed ro:
• 
establish ihr lateral and vertical variation of rhe various soil types
• 
t'Slabbsh the depth to solid rockhrid in rhe ‘rocky’ ground' arras, and hence die ease cd
excavation;
•      c^mblish the ground conditions at vinous proposed structures;
•      provide samples of the various soil types for laboratory testing
A total of 42 hand dug trial pits and one hand auger were excavated approximately along thr
line of thr left bank and right hank main canals and spread throughout the command area lw« • Trial piis were continued with hand auger follow-OrE A summary °f each trial pit and hand auger is provided in Table 3 5 and Table 3-6.
Table 3-5: Summary' of trial pits, augers and fiamphng for each irrigation development
Tr
Area
Number of trial pita and hand
augera
Numbers
Sragr 1 (upper right bank]
2d
TPB 4 to 13
TPB 17 to 26
Srage III (lower right bank)
11
1TB27 io 37
Stage IV (upper left bank.
7 trial pits including 2 with hand auger follow on
! hand auger only (TPB 5 3)
43 to 47
49
52 to 53
Stage V (lower left bank)
4
11*038 to 41
Total
43
Table 3-6: Command area trial pit, auger and sampling derails-
Trial Pit/
Auger bole
Coordinate*
No. af Sam ples
Exating
Final
Depth
Northing
D
E
Shear
Vane
tcila
Objcctrvrn
Area
TPB 4
243585
1255575
D.43
1
-
Main canal bur.
Stage I A, Right Bank
TPB S
240660
1287536
7
-
1
3
Main canal Line.
Stage LA, Right Bank
TPB 6
239331
1286608
2,6
■7
1
Mam canal line
Stage 1A, Right Bank
TPB 7
235345
1255582
1,5
2
-
2
Main canal line
Stage !At Right Bank
TPB 8
232695
1283560
0.25
-
-
Main canal hoc.
Stage 1A. Right Bink
TPB 9
229084
1382214
2 SB
-
7
3
Main canal line.
Stage 1A, Right Bank
1 TPB 10
225829
1278607
2-6
•
1
4
Main canal Line.
Stage 1A, Right Bank
TPB 11
221542
1276465
4.6
3
1
4
Main canal line.
Stage 10, Right Bank
UB F4 SRlMC Grotexh Fm 1 {1j
27
14 May IIFmtru! Df**ruftc Kfpitbi.' <>,' L/httfsfA Afrvjfr? */ U- j' rrr C*” /: w/rp
j\*/4r                    Dnan^t PrvftA
Trial Pit /
Auger hole
Coordinate!
No. of Samples
Halting
Northing
Final
Depth
(m)
D
E
Shear
Vane
lean
Objective!
Arti
TPB 12
217950
1273420
262
-
2
4
Main canal Unc.
Bini
TPB 13
214785
1268180
1
-
1
1
Main canal line
StigenT Right Bi^
TPB 17
227024
1280149
2.33
-
1
3
Main canal line.
Stage uT"
Right Bank
TPB 18
231911
1279477
2
2
-
3
Command area.
Stage 1A, Right Bank
TPB 19
226007
1274784
2 55
4
1
3
Command area.
Stage  IB, Right Bank
1TB 20
224957
1271270
2
3
-
4
Command area
Stage IB. Right Bank
TPB 21
220505
1269005
245
2
1
4
Command area
Stage IB. Right Bank
TPB 22
220471
1265693
27
2
•
4
Command area
Stage  IB. Right Bank
TPB 23
217847
1268792
2
2
3
Command area
Stage IB, Right Bank
1TB 24
217231
1262540
1.05
-
1
1
Command area.
Stage IB. Right Bank
TPB 25
217232
1258225
0.1
-
-
•
Command area.
Stage IB. Right Bank
TPB 26
216868
1265221
0.1
-
-
Command area.
Stage IB, Right Bank
TPB 27
209364
1259088
035
Main canal line.
Stage III, Right Bank
TPB 2R
208137
1256496
23
2
3
Main canal line
Stage in, Righ* Bank
TPB 29
211194
1254917
3
3
4
Command area.
Stage III, Right Bank
1TB 30
208997
1251117
25
1
3
Command area
Stage IIT. Right Bank
1TB 31
2O6’51
1250952
1.65
2
1
Main canal lme.
Stage III, Right Bank
TPB 32
204900
1245214
3
1
1
3
Main canal hoc.
Stage III, Right Bank
TPB 33
203379
1240998
2
2
•
2
<■
Maw canal line
Stage III, Right Bank
1TB 34
213293 --------------[-
1252837
3
2
2
4
Cixnmand area
>tagt in.
<ight Bank
TPB 35
211100
1248069
28
2
'j
3
Command area
Stage 111,
UghLBaflk
TPB 36
209038
1243378
285
2
1
4
Command nCa -______ ___ 1
rage III, Jght Bank
UB F4 SRO4C Grnreeh Pan I (1)
28
N-May.11Jfrtrffrr nflFiil/r t^Entljy
lifM-fiiff A /A Jrwprtw* <r<4 Djwtjw- P>W
r
Trial P« /
Auger talc
Coordinate*
No. of Samples
Easting
Northing
Final
Depth
(m)
D
E
Shear
Vane
irate
Objectives
Area
77*3 37
207408
1241008
Z9
1
2
4
Comma rid arei
Stage 111. Right Bank
7TB 38
214135
1241801
T
3
«
Command area
Stage V.
Left Bank
TPB 39
21"052
1237224
3
3
1
•
Matfl canal line.
Sugr V,
Left Hank
TPB -KJ
225757
1241154
4
4
-
Mun canal
5ne.(lland Auger follow on)
Stage V,
Left Bank
TPB 41
221231
1246797
2.6
3
1
*
Command am.
Stage V,
Left Ban*
------- —
7TB 43
220086
1256138
14
«■
-
Command area.
Stage 1VC
Left Bank
TPB 44
228095
1253344
06
2
-
Command area.
Stage I VC fjtft Bank
TPB 45
241775
1254660
2 45
2
1
2
Main canal line
Sragc TVC
Left Bank
TPB 46
226565
1260075
15
2
5
2
Command area (Hand Auger
follow on)
Stage TVC
Left Bank
17*0 47
234979 .
1258256
1.5
*»
#•T
■
Command arm.
Stage 1VC
larft Bank
TPB 49
235839
1264532
1.2
1
1
-
Command area.
Stage D’B
1 xft Bank
TPB 52
233827
1272647
0.9
1
1
-
Command area.
Stage 1VB
Left Bank
TPB 53
24364)1
L
1273002
11
3
-
Main canal line (Hand Auger .
Stage DT3
Left Bank
The trial pits were logged in general accordance with BS593U (1999) (ref 8). Small disturbed samples (D) and large bulk simples (B) were taken for laboratory testing. In situ hand shear vane rests were undertaken tn accordance with BS 1377, Part 9 (1990) (ref 7) to establish the Lunkamed shear strength of the cohesive strata, One shear vane test nimpiina a set of three results undertaken ai each location io gain an avenge test rrsult.
LfR m SRtMC (kwh r n I (1)
4
29
14 .M .1V -11N* W*3' J’j P'B,'Jr Pr^'r
‘ ” iCu^X* “*" 
summarised in Table 3*
"“,he i‘mpl" "‘“ fr"m tbr “"B
«<
Table 3-7: Summary of laboratory testing on samples from drilling investigations in tht Command Area
Test Description
Number of
Tests
Test Standard Used
7
BS 1377:1975. Test 7(D)*
Natural Moisture Content
B
BS 1377:1975, Test 1(A)’
Plisnc and liquid 1-units Atterburg TeM)
14
BS 1377:1975. Test 2(B) and 3*
Linear Shrinkage bmit
7
BS 1377:1975, Test 5*
(>nc Dimensional Consolidation Properties
5
BS 1377:1975. Test 17”
pl 1 Value
3
BS 1377:19 5*                  _____________ '
?
Head, K.H, 1980. Manual of Sod Laboratory Testing Volume I. Soil riaMifaation and cnmpaciMn frttt I lead, K.l I.. 1982, Manual of Sod Laboratory Tc<ung Volume 2 rermcahhn. shear strmgth and
comprrmbtbty tear*
Head,K.H . 1986, Manual of S*jfl laboratory Icstinp Volume 3. Effective stress test'
Hie laboratory testing undertaken on the samples from die trial pits and hand augers is summarised tn Table 3-R.
I BI-4SRCHC Gcotcch Pin I .1,
H May-IIHVfayw
.Itartoy ?Jf IFnfrr ■+ L »rri
andDrjrwapt Prwa
Table 3-8: Summary of laboratory testing an sample* from trial piis and hand augers in the Command Area
Tcflt DcucnpUotl
Number nf
Tests
Trit Standard Used
______________
Fartidc Size Dutribuhon fPSD)
1
HS 1577:1975. Tert 7(A)’
Sedimentation by hydrometer
32
BS 1.I7  :1975. Tell 7(D)*
-7
Natural Mouturr Contcnr
32
BS IJDil'l'S. Tot 1(A)’
Piastre ird Jjifuid Limit* {Arrer burg Test)
32
BS 1377:1975, Tot 2(B) and 5’
Linear Shrinkage Limit
32
BS B77J975, T«r 5*
Organic Matter Con tent
31
BS 1377.1975. Test«’
Mm* Loss on Ignition
20
SMRE (1952)’
Compaction
13
BS 1377:1975. Test 13"
Swelling Frcsiure
9
• -
Direct Shear
3
««
Dispersion by Double Hydrometer
9
ASTMD422V
Permeability
12
ASTM 132434"
.Sulphate Conirnr of M ater extract from sod
18
BS 1377*1975. Tetr 10*
Aod Soluble Sulphate Content
18
Bs 1377:1975, Ten 9*
pH
5
BS 1377:1975’
I kail, KJ!, 1980; Mani;inJ cd 5ml Iainurawwy Jesting VuIueiw 1 Sail daiuufKatirm And compict™ evki® I lad, K II , ]*>82, Manual »nf S<ml Labrirahity Tcinntf Volume 2: Prrrrw-jlbifary, shrar srren^h and
com prcstibililv Irato
d.6 Darn Sire Mid Reservoir Aren Ground Investigation Work
J-6.1 
and Rfi.unnaxjjatia W'aihurr
A study was made in Apnl 2010 of four potential darn sites and two porenual left bank weir offtake location $ on the Beles river. The approximate dam locations are shown in Figure 3 6 and are summarised in Tabic 39 The potential dam sites weir chosen based on topography, stage-storage relationships and dam volume to reservoir volume effiacncv This is reported in rhe Supplementary Repon .SRO4B bj igineeiing: Storage Dams
A reconnaissance geotechnical arc visit wu made on 28th April 2010 to the two uppermost
1
potential dam site Incahnm. (Dim Sue +1353 (*1) and + 1338 (‘2 )) and the polcnual war location* on the Belos River. The two possible locations tor the war were just upstream of die gurgc at Dam Site 2, and juM downstream of the gorge
1 - HT I SRtHM GftH^ch Port I ft)
31
M May 11Figure 3-6: Approxifnatc Locations of Four Potential Dam Sites h • 7/*
v ■■ <
Dam Site
♦□S3
I
U|>p«*« Bries River (lift? n indicative)
1 iAUIV Dim Site .
(bed
elevation)
uiasl
lial dam sites
jgroi* storage)-
1 Provisional Dam Details (175Mm'
mirage with 5m freeboard)
Gnd        |
Reference
Great
Level
(mail)
Crest
Length
(m)
Dam
Height
(ma*l)
Comments
1 (1.353)
26I950E 129575ON
1.415
1.180
62
Narrow gorge just downstream of Kwarimna .• Held confluence Would impact on 2 wan constructed for HEP project and require a ?< 1 diversion war downstream lor the lett num^JfL
1 2(13'8)
261200E 1293-SON
1.399
1.040
61
Clmc to left bank diversion war so can meury’ *’
1     11
left lank canal draw-off into dam design instt*^
a separate weir. Has potentlid for a saddle on n» side to be a tpJJwav. depending on dam hcigh^—-
r 3(1.292)
| 255650E I 1292000N
n/a
n/a
n/a
Downstream of proposed location of left vCir
wou'd flood loth the left bank diversion weir
left bank mam canal at elevation at or above
l 345masl. Therefore this site was re cried —
r
4 (1’S?)
25115OE 129325ON
1313
2.430
56
Downstream of left W divenion weir, limit’ flexibilnr / etUaeno of ,.<„g     ,  p|nng riK '
c by   up
h
| l»nk command >,« uni,.,                                       wc*
| r^mrrd .ddmg    co.L Xo 
l0
(sUge.
J-
-
Jtlongeiidvanjagw£
i h . i SR K< Genscdi Part 1 I)
32
U May It•/ L/fraOr*/, Aff*rxp rffTafrr & Enrrgp
H/Ar^ww Nr# /'ng*** Dnutta^ Pnttcr
The objective of the site visit was primarily in confirm the dam site location and plan ground investigation work (more detailed mapping, trial pitting, geophysical survey and boreholes) The selected dim site is Dam Site 2 (+1.338 masl) 'Airh a combined left bank canal draw off structure. For dim design options were considered. (A to D). The preliminary layout for dim option C (the highest dam option J is shown in Figure 3-7.
Die dam crcsi t$ orientated <SE-NVC  and is slightly obbque from perpendicular to the cur rrni
r
rrver channel The spillway is located in a col to the left of tbr main dam. The darn forms a straight section la rhe cenTre of die valley and rhen curves downstream, following a ridge on the right abutment-
The point where the dam axis crosses the over is approximately GR 201060E 1293720N with a lowest rlcvauon tn the vallry bottom of about +1,328 mast For preliminary design purposes
the dam ixis is defined by the following three coordinates:
•  DLI: Left (east) side of spillway:
•      DL2: Right side of spillway;
•      DR2: Right side of valley
0261680   E
1293480   N
0261380   E
1293480   N
0260965   E
1293825   N
•       DR I. Right abutment.
0260536 E 1294056 N
Between DLl and DL2  the axis is curved with a  plan radius of 1km,  erntred downstream ot the
axis.
UH^SRD^GciTcdi h
1TT I (1)
33
14- May 11Ftdrra/
Miat/fry * ITjfrr r*» liw*»©
Efixtptja Site Ir*&f>9* and Dr^^t Profit
Note: Rorrf-ok l.'BDOJ ><»< Mphl'd th" r. n.lky Jloodix.t b» th, Ufh, HliP -h,"'RrtMr <                Mmtiry af ET'^r’ d“ Dr/ij.
t/Wv*’T jX7> jFrt^r-'wt Diwwr Pwr
4 $ 2         Sif/twary 0/ rDa* SfJ' a*d Rffrnw sfrrafnwid sjfiwtrgrf&rt wrk.
Ground investigation fieldwork in rhe Dam Silt and Reservoir Area was carried out betwren April and November 2010. Thu was followed by laboratory testing which was completed in December 2010 A summan  of the activities completed i* provided in Table 3-10. Ground investigation locatmns m the Dam Snr and Reservoir Area arc shown on Drawing
ITB/FS/GEO/F/Ol (see f igure 3-1).
4
Table 3-10: Ground
investigation works in the Dam Silt and Reservoir Area
Activity
By
Description
Reconnaissance geological walkover / dam site selection
1
IImIccow / GIRD
Study of potential dam sites based on topography and stage-storage reJaticMisshLps. April 2010 from digital rernin models, Aped 2010. Site visit 28th April 20ID by Enginrering Godoghls and 1 ivdrolojjists.
GenEogicaJ mapping
Halcmw / GIRD
May -J ulv 2010, during borehole supervision and trial
pitting
Geological mapping of the dam site and reservoir area also included rhe aJtcrnaiivr potential dam utc ‘1’ and rhe wvtr sites, which are located rither in the reservoir area or close to the dam site
Tnil pitting
Hale row / GIRD
5 number trial pir% (UBDP1 to 5) to up to 3m depth, completed m Mav 2011]
Laboratory les ting of iruj pit samples
Water Works Design and Supervision
Enterprise
Basic    clusificatwn    testing    on    bulk    samples    of    superficial soils, result"! received J uh- 20 ID
Boreholes and in situ i pcrrrwratiilily tens
Addis Getnyitems
____________________________
[
Geophysical lurvcy
Mobilisation     14     tn     28/05/2010.     Dolling     commenced 03/06/2010, completed on 10/11/2010.
Sn boreholes (UBIX1, 02.04, 05, 06, 07) to depths
ranging from 10 to Xhn, 4 dong the dam axis, 1 ar thr
proposed spillway, 1 at the dowTiitream toe of rhe darn.
(Burehole UBD03wa» not completed due |n flooding
following commissioning of the Tam-Belts 11 EP
scheme).
Lugron tesrs, falling head and constant: head
permeability test*.
Laboratory    testing    compnsing    cbuufitatMjri    and    strength rests on snd and rock sample <
Mngn Tigabe [Sub- cnnEultanr
Geophysicist)
Four survey lines, with work nn left side of the river completed in July 2010 and work on the right side completed in October 2010.
on 1-4 SR04C Gftftdi |*arl 1 fl)
35
H-May-11X/* W’"”” JKi
Dn/tflg IWWlgUHW"
So boreholes (UBDOi. 02,04,05,06 and 07) were completed in t|le dam site Mea [(
50m depth, with four on the dam axis, one at the spillway weir anil one downsrream possible, five meter long packer permeability tests were completed in the bedrock m ** borehole, with vanable head permcabdin tests in sods where appropriate. Borehole provided in Table 3-11 and locations are shown in Figure 3-1.
T,hl, vi 1- Borehole details at the L
fpper Be les Dam Si te____________________
1
Borebok
Easting
Northing
Approx.
Ekv.
(marl)
Total
Depth
Comment!
L’BDOI
261217
1295594
1562
30)
Left abutment
l-<)rr. along geophysics line 1
UBD02
261090
1293-00
1331
50
Centre left side of channel
322m along geophysics line 1 123c: along geophysics line 2
UBD03
261025*
1293740*
1333*
20*
Centre right side of channel. *Afof compktcd  due to  flooding  from Tint-Beks HEP
UBD04
26OS6U
1295860
1368
30
Right side ridge. Terminated in soils. Did nor reach bedrock due to dnlling difficulties
UB1)O5
260685
1293995
1385
15
Right abutment
UBD06
261090
1293700
1350
10
Downs!ream left side
140m along geophysics line 1
vbixt
26160(1
1293420
1418
35
J
J
— ■------
Ixft saddle area, for possible spdiwav location.
75m along geophvuc* line .5 ---50m----- al ---on- -pg ge "—‘op" hvsics line 4
Note bon ho it titvaltonj an taken from tht digital t If ration model and an jlightly different to those mvrded r* the AGCLfartxat report front GPS orjrvm pnpottd titpalwni.
.Ml drilling equipment had to be hand earned to the dam site, over a distance of about 8 to 10km. and therefore mobilisation took about 2 weeks (14* to 28* May 2010) Drilling commenced at borehole UBD02 on 05/06/10 and was completed at BHUBD04 on 10/11/10*
Due to the release of water from the Tana-Beks IIEP scheme, it was not possible during the site works to cross the Belos River below the lowest HEP bndge crossing Therefore, the «<c works were split between the two sides of the river and the left side w as investigated first
/
r
Proposed borehole UBD03 on the right side of the valley near to the river could not be completed due tn the nse in nver level caused by the Tana-Beles HEP scheme discharge
Drilling results are reported in the Addis Geosystems Ground Investigation p I Report, January 2011 (Annex E) and the results ate reviewed in Section 5 S
I JR H SRO1C Gctxrch i'arr 1 1
36
14-May.jITjf/r & [i/urg
F/M** * 
r
Vl * /”«**«*
J 4             CMpbytin/ Survey.'
Two dimensional geophysical rcmiiviiy profile lines have been run in the Dam Site Area as four transects, shown on Drawing UB/FS/GF-O/F/Ol- A schematic location plan of survey lines relative to boreholes is shown on Figure 3-8. Die positions of boreholes alone the lines we  provided in Table 3 11 Coordinates and lengths for die geophysical lines are shown in Table 3-12. The geophysical survey report for the dam site area is prosided in Annex G<
•r-rfli
7inir
-4- TwcpiijfHs Lr*2
—*— >X/nKhJrfrJ
1 ??^KC —0— ij«pf yacii LilifrJ
-t-lW/
I -*-uaoj
--uro j
•- JX*
I • -S-JHD5
/^UBPe
i?iX<r 7 —------------------------------ -
*------ H I--------- A
?feta
2OTC
Mt2D0
u«X'Ns.4-iLlrc 4 jflisoo
261800
Xsfts. (J) Net to scab; (2} BH ttBDOI/rof eoMfltfed due to flo&fo&frvM /fa TsMa-Be&f i i LLP xfame; (3) BH l.'BD? i< at the iftfewtwn a/'^wj ? urfi/4
Table 3-12: Geophysical survey Lines at the Upper Beks Dam She
Geophysical Survey
Line
Bailing
Northing
Location
Comments
Line 1 Along dim jaua (14(H) mail ts assumed Crest level / end of
abutment)
261340
1293520
End of kfr abutment
260685
1293995
Slight dogleg at UBD05
261MHP
1294085
End uf nght abutment
Completed remtivity survey on left title
13/07/10 Length 224m
+B09m
Line 2 Parallel tci river, left Mdc. centre of
valley
260992
129362?
D^wnsbrcam md station Dm
261090
1293700
Bend al about Station 120m
261260
1293752
Upstream end turion 300m
Completed rtsistrvitv survey  on 13/07/10. Length 122m + >78m
Line 3 Across  spillway 
war
261525
1293414
Rjeht side of spillway weir
<Jrienlated E XX'
261675
1293415
Left side of spillway weir
Line  4  Dri’iti  spillway alcipc
26166*'
1293470
Saddle crest
261600
1293220
Farmed slope sout h of saddle
< Irientatcd N-S. Slightly offline, to check downstream vaUcy
UH F4SRO4C Creech Part I (I)
37
14 May I ]f’tdrnd              fapMt afF.f hepta, Affurifr) •/ ITaft* & F.ntrp
Fltiepus A’dt Imjati)* and Druinape Prqtrt
3.6.5 Trial Pitting
Five had dug tnal pits were completed in the dam site area between 7A to 8* May 2010 to depths of between 2 and 3m. Locations arc summarised in Tabic 3-13 Bulk disturbed soil samples were collected for laboratory testing and tn situ hand vane tests completed Results were received July 2010. Tnal pit logs, photos, and lab test results are provided in Annex H
Tabk 3-13 Trial pita at the Upper Beks Dam Site
Trial Pit
Easting Northing Approx. Elev.
(maxi)
Completed
Depth (m)
-
J
TP UBDP1
261155
1293708
♦ 1,332
3
Upstream  of  left  abutment, valley terrace
TP UBDP2
261315
1293535
41,388
2
End (top} of left abutment
TP UBDP3
261267
1293603
+ 1,366
2
lx ft abutment mid slope
TP UBDP4
260844
1295899
+ 1.370
2
Right abutment mid slope
TP UBDP5
260991
1293961
(+1.M9)
2.5
Upstream  of  nghr  abutmet^ valley terrace
Note: trial pit logs rApir shfhtfy dtffmnt titvationf hastd on an tariitr DEM and sift GPS data
J. 7 Ground Investigation Results
The ground investigation data are presented in a senes of annexes, as summarised in Tabic
314
Tabk 3-14: Annex Contents for Ground Investigation Results
Annex
Tide
Cooicota
A
Dam rife drilling  and core
photographs
Photographs  taken  by  Hale  row  /  GIRD  dunng  reconnaissance mapping and ground investigation supervision
E
Dam lite drilling investigation final factual report, Addu Geosystenu Co. Ltd.Januarv 2011
Report  lontaimng  borehole  logs,  in  situ  test  results,  monitoring and laboratory rest results on samples from boreholes.
F
Dam site slake durability results
Slake soaking tests by Addis Gcosvstems
G
Dam  ute  geophysical  survey  Final Report, January 2011
Report  containing  2D  fcriativiiy  geophvucal  methods  and results by independent sub-consultant
H
Dam ute area rnaJ pit logs, photographs and lab test results
logging  and photographs by  Hakrow / GIRD.  Laboratory testing  by  Water Works Design and Supcrvuion Enterprise Laboratory Service dated Juh 2010
I
Right hank main canal dulling investigation factual report
Report containing borehole Jogs and test results bv Addu Geosystrms Co Ltd dated Apo! 2010.
J
Geophysical survey report, nght
Sank uru
Report containing 2D resistrnry geophysical methods and results by independent sub-consultant.
K
Command area tnaJ pit logs and photographs
Lofjmg and photograph, br Halcrou / GIRD. Photo.  f pits
o
and ansings
L
Command area uul pit laboratory rest results
Tct result sheers prwrded by WWDSF. dated Fcbn^    0
annexes divided per proposed development  . 
or
Ml
-—q----- -
UH P4SRCMC Gcorcch Part I (1)
58
H-.May-llpMrfll/
P.lhitjvs, Mjvf.-ry tffFafrr & hw&
Vffv3ri.r.i frraptf** ' ^ •P'Tir»raji>e- Pnjwrf
J
j afi              Hydraffeotoffca f Ffc/dnvtrfc
fieldwork. specific for hydrogeological assessments included
•      Discussion with pertinent region, zone and Woreda Miffxnd largctrd beiwiicuuie.* regarding development nf the ground water resource, existing ground water supply, constraints, prevailing water demand and supply, imgation developments and future plans regarding ground water development in the area:
•      Collection of information from local villagers regarding existing water supply soarers and condition of supply / utilization, water demand. constraints, existing ground water potnts (spring and wells). sustunabdiry and fluctuation of discharge/yield.
•       Inventory and geo referencing of existing water points in the I 'ppct Belts dam site and reservoir ires and irrigation command area,
•      Hydrogeological survey and mapping nf hydrogeological units.
L 1H'4SRIMC Gcniech Part 1 : l)
39
4 -May-11- I' II
II
I
II
I'
iIAfre/fry af’ITjfrr C+Ewp E/iw0« NJ* W"'**
£> Pn^rf
4
4/
REGIONAL GEOLOGY
Introduction
Lake Tana lies ac m elevation of about + 1,785 masl, while rhe dam sire area is at about +1,330 mail and the command area largely between +1,000 and *+1 JOO masL Ihe area is broadly on [he ‘'Western Plateau” physiographic region of Ethiopia, to lhe north west of the Rift A alley-
The geological units of Ethiopia fall into one of the foUouhng three major categories the Precambrian basement, late Palaeozoic co early Tertiary sediments, and recent (Cenozoic) volcanic and issociaied sedimentary rocks. A general stridgraphic sequence for the Nile Basin is surnmariHrd m Table 4- L
Table 4-t: Nile Banin Geological Stratigraphy
Age
Mapping Symbol
Formation Name
CENOZOIC
TERTIARY A
QUATERNARY
PJiq - Quaternary
Pp
PX
Q*
Tv
T.
TP
To
Tk
r°
r lT3
Tc
Magdala group
Rhyolites
Ignimbnie
Alkali trachyte & basalt
Shield group
Wrlaga basalt
'1 armabex ba$all
------
Jimnu vokarucs
Omo barali
I'ndiff. Volcanics
Ambajd|i basalt
Ambaaiba basalt
--------- tfirpniijr awHfprmtfr
Ashangc lusalr
Blue Nile basalt
Ashangi group
Eocene - Miocene
MESOZOIC
Kjl, Ks
Jt.J’ J5
Ambandam Sandstone
Basalt flows, ruffs
Antalo limriltMiE
Adigrar sandstone
PALEOZOIC
d, Pzt
Pit
Adigrtt classes
Edagarbt sandstone
PRECAMBRIAN
UPPER. PROTEROZ< HC ARCJIARN
Rtl
gb
Ub
PCJt
P€31
PCJt
PCI
-----------------jWii.'wr
Syn tectonic granitoids
Gabbro
Post tectonic granite
ultra basics
Tmkrjv
Phylire. quartzite
Tsalier group
CHocie, sericire
Adali group
Gneiss
L'R F4 SR4MC tlrnrech Parr 1 11 •
41
14-May 11r-tar^J Pr-o.T n. 
tl
M-vJfn "IVtrr r*E'^
Ethiopian Nir l/rig&M and Dnrn^t Prytrf
The region is underlain at depth by Prccambnan basement rocks (mainly grarutes and highly metamorphosed rocks), which are partially covered by Permian to Palaeogene sedimentary rocks (mostly sandstone, limestone, shale and marl), which arc themselves overlain by a thick sequence of recent (Tertian- and Quaternary) volcanic rocks (mainly basalts) and associated sediments (mainly lithified tuffs).
The basement rock is exposed where the area has not been intensively affected by volcanism
and where the sedimentary rocks have been eroded away Basement rocks only outcrop to the southwest in the lower reaches of the Beks Basin at the downstream end of the Command
Area. There arc no extensive outcrops of Mesozoic sedimentary rock in the Tana Basin or Belts catdiment, but they arc observed in the Abbav valley Io rhe southeast The predominant geological units affecting engineering design are therefore extensive sequences of Tertian' and Quaternary volcanic rocks of mainly basalt and tuff.
The Upper Beks catchment forms part of and is on the south western edge of the Lake Tana Sub-Basin’ physiographic region and geological structure. The regional geology, structure and hydrogeology presented below includes extracts from the SMEC, May 2008 I lydrvgroioficai Study of the Tana Mr J Sub Hajin Mam Report (tef 6/
42 Regional Geology
The geological map of Ethiopia (1:2,000.000) 1996 (ref 1) (Figure 4-1), indicates that the Upper Beks dam site, reservoir and command areas arc characterised by basement metamorphic rocks and post tectonic granite m the lower command area. Ternary volcanic rocks of rhe Ashangc and Tarmaber formations. Quaternary plateau basalt and recent alluvium
The map shows the Beks dam site tn compose the Eocene age Ashangi Formation (unit Pza), described as deeply weathered alkaline and transitional basalt flows with rare intercalations of tuff, often tilted tn the north and west of the dam site (in the reservoir area) and further to the southeast (just outside of the project area) are volcanoes formed of the younger ( Jligoccnc Miocene age Tarmaber Gussa formation (unit PNtb), alkaline and transitional basalt with trachyte and phonolite (fine grained alkali igneous rocks). The escarpment to the east is shown as Quaternary age plateau basalt (unit Qbi). described as alkaline basalt and trachyte.
The northern pan of the command area is also shown to be Ashangi Formation basalts, but the southern lower reaches of the command area arc shown as the older Tulu Dimru Group (unit PR?td). These rocks are described as late Proterozoic (Prccambnan basement rocks) of several different metamorphic lithologies: meta-basalt, meta-andesne, green schist, phvlhte meta conglomerate, quartzite and marble
The map also shows a large complex of Prccambnan granite intrusions southwest of the command area At the scale of the map, it is therefore posstbk that smaller
. 
, 
, 
, 
rr
of post or
syn tectonic granite, granexbonte and tonalite (diontej occur tn the southern half of the command area, but are too small to be shown on this map
UH H SROIC Gcnrech Part I (1)
42
l4 *Miy 11Af/wr/rj1 of\l'aftr r^Ettr?
Figure 4-1: Regional Geological Map (extract from Geological Map of Ethiopia, 1996) Geological Map of Lake Tana Sub Basin
LEGEND
JUluvhl DtposlH
(j. Quaternary Bai aft t
Tvrmabtr Basalt
JUba Bat alt
Ashangl Formation
Arnb-i Aradlom Formation
Ant al» LlrresCDn*
Abay Formation
Adlgrat Formatton
Fronz
Ge stogie >1 Map of Ethiopia
Second Edition. 1$«
4-2. /          Raj t mt Hi Mtfamorpbt;
Tins variable unit is shown to cover a considerable part of the southern command area These arc meta basalt, meta andesite, green schist, phybte, mctacongkimetate. quartzite ind marble Such lithologic units ire mainly low to medium grade metamorphic rocks classified under the
1 ullu dimtu group igrological map of Ethiopia. 1996). I hr Ahbay .Masterplan does not differentiate, but terms these rocks *‘undifferentiated lower complex”
4 2,2 Pw//ft/flff* Gnnttfr
rhe rock is found exposed at relatively  small part of the southern pan of die area.  TTie rock typically  contains microcline,  a  smaller amount of plagioclase,  quartz and a  little bionic I Tic rock have been dated as from 690 to 450 My
1 H SRD4C' ticrrtwh Pan 1 (JJ
43
14-\hy-11Mirn iflF*tr&EafW
[■.ttyu*  N r>
T
Dm^t
42.) M&yu StdimfHfarr R*'&
The basement rocks are overlain by extensive deposits of Mesozoic sediments, which are exposed in the Blue Nile gorge to (he southeast. These sediments do not outcrop in the Tatu basin Recent geophysical studies south and east of Lake Tana have indicated up to 1 5 2km thickness interpreted to be Mesozoic sediments preserved in a northwest trending half graben structure be neath the Ternary volcanic cover Thicknesses identified in lhe geophysical profiling appear to be consistent with the section exposed in the Blue Nile gorges The Mesozoic
sediments have noi been confirmed beneath the basin by intersections in boreholes
The basal unit of this sedimentary sequence is the Jurassic Adigrat Sandstone, which consists of fine to medium gnuned. well sorted, cross bedded sandstone, overlain by limestone shale and gypsum comprising the Abbay Formation, the overlying Aniak* Limestone and Cretaceous sandstone, conglomerate and shale composing the Amba Aradom Formation. These units arc exposed in the Blue Nile south cast of the Lake Tana basin
In the Bries project area, (ie. Beles dam site, reservoir and command area), no outcrop and evidence of this unit is observed. However, roughly 8km SE of the dam site, along the dam sire
Yismala rural town foot path, there is an outcrop of reddish brown to greyish brown slight to highly wraihcrrd medium grained and horizontally bedded sandstone, possibly of the Adigrat Formation. It occurs on the side slope of gorges underlying the basaltic rock unit. This unit is not shown on the regional geological map
4.2.4 Ttrftan I 'ohaKtc
Tertiary Volcanic sequences compose lhe bulk of the outcrop in the areas surrounding the Lake in lhe Tana Basin and in the headwaters of die Beles These compose a number of different Tertian volcanic units which unconformablv overly rhe sedimentary and basement complexes. The volcanics van* in character based on composition, structure and degree of weathering
These rocks are exposed as small outcrops towirds the west, northwest and cast of the command area, and arc relief controlled, forming high ground on the periphery. The units arc also found extensively further west and WX ouiside ihc command area, and Tertiary volcanic rocks units form the geolog)' found in the nanny of the proposed dam site.
The maui volcanic unit recognised in the area is the Eocene Ashangi Basalt, composing deeply weathered basalt lavas and pyroclastic units, as well as the Alba basalt (flood basalt with rare ruffs) which is mapped to the north and northeast of the Tana Basin. These units represent the broadly distributed Volcanic Trap senes across northern Ethiopia The Ashangi Basalt unit is characterised by olnnne basalts, luffs and intrusive rocks of alkaline granite and s venire
In the immediate vicinity of the Upper Beles catchment and the Tana Basin the trap sc basalts arc overlain by the Tarmaber Basalt (Miocene Ohgocrnc dated 3O-13Ma p b bl droved from the Shield V olcanoes of Mt Guna and Mt Choke The Tamubcr basalt across large parts of the catchment and comprises alkaline to transitional basaltic U urcroP!> (trachytes and phonolite), intercalated tuffs, scoria and red-brown paleo mhL
HR E4 SR(MC Gerrfrch Pan 1 (1)
44Rjpjw/i’ ofE/An^mc, 3 jw.-Xr/ of fFanr & Ettrnp
E/fafM* AM                          P«>ffJRr P^.t
The thickness of the trap senes in north-western Ethiopia avenges 1,000—1,500 m, and in the Blue Nile gorge, there is up to 250 m thickness of lava flows. The approximate elevation of the base of the Tertiary basalts in the Blue Nile is around 2000m (based on the 1096 geological map and the Digital elevation model for this project). With the height of Mt Choke around 3,000 m, the thickness of lhe combined Trap basalts and the Shield volcano sequence could approach
2,000 m decreasing away from the main volcanic peak.
^ 2.5 
I'efavm'IteJb
Quaternary volcanic rocks overlie the older Ternary volcanics over much of the Gilgr! Abbay
catchment south of Lake Tana, extending south fmm Bahir Dar to beyond the Gilgel Abbay
catclimcnt boundary Well preserved eruption points for these lavas arc visible to the south of
die Kake Tana. The Quaternary volcanic sequence comprises blocky and fractured vesicular
basalt, with a porphyritic, glassy texture, as well as some basaJnc breccias and tuffs. Further
south, the Quaternary Volcanics arc kss blocky and have deeply developed soils. Fhe
Quaternary volcanics arc expected to be more than 11 Kim thick and perhaps as much as 200-
300m thick
Quaternary’ volcanic rocks are thought not to  be significant in the dam site area  and command area,  but detailed mapping  has not been complete J  to  confirm the age and origin of the basalts and tuffs ihar arc found at these sites
4.2.6          Riant Drfwttr
.'UluviaJ soil deposits arc shown to cover some of the lithologic units in thr area. They are likely to be found along the plain land, river and stream banks and courses and to consist of sand, silt, clay and gravel tnitenJ, dependant on the source rock material The GcologkaJ Map of Ethiopia (1996) shows an extensive area of alluvium ar high elevation to die NW of the dam site (Figure 4-1). This may be a nusintcrprctahon of remote sensing data. At thr Upper Belt’s river valley there is no indicinon of extensive alluvial units at higher elevation outside of the river valley.
The soils in most of the Tana Bavin are derived fiam the weathered basalt profiles.  lhey are
r
highly variable. In low lying areas, particularly north and east of Lake Tana, soils have been
developed on alluvial sediments
In  Hilly  areas,  such  as  the  Upper  Bries  dam  site  and  reservoir  area,  colluvial  slope  deposits  have formed, and there arc aka ourciops of river lerracc deposits on valley sides.
The Jjikc Tana basin has a complex tectonic origin, hemg situated at die function of three
grabens, forming a structural complex perched within an overall configuration of an uplifted
dome that was active during rhe formanon of the mid-Tertiary flood basalt sequencr into which
the basin k impressed-
Reactivation   of   faults   occurred   in   the   Late   Miocene   io   Quaternary,   with   down-faulting   of   die north-south trending Gondar graben (which is exposed by erosion in the north of the basin),
UR B4 JiRMC Grnicch Part 1 (I)
45
14-May 1]Faiiml Dt^ruric
oj Ethefta. Atiaiiln of W ater & l-.nerg
Ethnpia* Nt Jr IrrwfJ*' jkJ Drwtjft Prvjtrf
the north-south Dengtl Bw, (which is buned beneath the Qua tern arv volcanics in the Gd^j Abbav) and in the eastern part of the basin, the essentially East West aligned Debre Tabor Graben.
Analysis of fault and joint patterns and satellite imagery of the basin suggests continuing subsidence accompanied by block tilting within the grabens. The Tertian* volcanics are likely to lx down faulted into the grabens that form Lake Tana The slight subsidence and the presence
of a barrier of young basalt lava flows at die lake outlrt have kept the water in a shallow natural basin (ref 5)
The predominant structural trend in the area is shown as N-S and NNE-SSW faulting around the margins of Lake Lana Major N-S faults are shown to cross the Ikies river at about 5, 12
and 20 km southwest of 1-ake Tana, but the scale of the map is such that these locations will
not be precise. /\ major NT.-SW fault is also shown south of and in the southern command area, approximately aligned along the Main (Enat) Bcles River., possibly interpreted from the straight alignment of the over
Downstream and southwest of the command area is a separate structural complex of high density NE-SW and NW-SE trending faults associated with the intrusive rock units
The approximate elevation of the base of the Tertiary basalts differs across the region. It
ranges in the basin from around 2,000 m to depth of around 250 m Ihe base of the Tertiary senes is much lower west of the Tana basin in the Beles and Binder area at around 1,100 m. dipping to as low as around 600 m in the northwest Jt appears that within the basin, the geological structure suggests inward tilting fault blocks and an essentially flat base to the basaltic sequence, while the base of the basalt dips away from the Tana basin tn the areas surrounding the basin.
UH F4 SRCMC (ieciredt Parr I (1)
46
H May.JiAf/wZp of Frffrr c^Bwrp
N)>                       Dm^t Pnfta
5          DAM SITE AND RESERVOIR AREA GEOLOGY
g /              Zn frodu^Oon
The geology of lhe proper area is described below for the following areas, which arc the
principle locations of the main engineering work':
Reservoir Area.
Tzift Abutment
Dam Sire and Reservoir Area
Central Valiev
Right Abutment
Spillway
Right Main Canal Off-take VC’eir Site
Command Area
Main Canals
Geological mapping of the project arcs is <hown on two Al size drawing?, it 1:100*000 ind
L 10,000 scale
•      UB/FS/GEO/100/01: Upper Bclcs Command Area Geological Map (see Figure 3 4);
and
•       LTB/FS/GEO/IO/02: Upper Bdes Dam Site and Reservoir Area Geological Map (see Figure 3-5).
The maps are based on geological mipping and ground investigation. Tn the command area geological mapping has been combined with soil survey mapping Soil survey work has mapped and spot sampled at greater density than gcoirchnicil work and where appropriate geotechnical units arc correlated to the soil survey and used the same soil boundaries to dilferentiate
gen technical units.
Four potential dam site and reservoir location options weir assessed in the Beks river valley, with project specific reconnaissance geological mipping at the most promising upper two locations previously known as Dam Site 1 (+1,353 masl)' and Dam Site 2 (+1,338 mas l)M. The proposed dam site is lhe ’dam site 2’ location. Geological mapping extended over the reservoir area and some of the surrounding hill tops (where lherc h often bener exposure), along the access routes from thr Tana Beks HEP scheme and from Yixrmla, and approximately I km downs ircam of the dam site and spillway
During and since completing geological mapping, the Tana-Bries hydropower scheme has become operational (from 14   May 2010). with high discharges (i.c. 77 m /* <»r more) released into the river. This is resulting m regime change to rhe over system, with erosion and redrposition of superficial deposits. Therefore, lhe location and type of superficial deposits in rhe valley bonom that is described below may have changed since the mapping penod bciwcrn April and July 2010
th
3
Refer Upper I'cisLbilny Sriiily Suppler, eras jry rqwirr UR F4 SR04C Cknltxh Tart 1 (1)
fur at mime nt nf dun Incitinn cjprinm
47
14-May 11Wnl
E&fin Silt lmfiib" nd Draiagf Pryrf
Mvrt? ofVaftr^E^
Specific geological and geotechnical descriptions for all strata encountered m borehole* and f^. pits iff provided with rhe logs as annexes to this report. Also included in rhe annexes arc photographs of die borehole core, trial pit excavations and trial pit arising?.
Locations arc provided as a gnd reference to the Adindan grid Geological descriptions of catf, unit arc in general accordance with BS593CH 1999 ofPnriNfJbrfite hwti^lron^ (ref 8)
these arc shown in italics in the trxt below.
5.2 Project Aren Geologicnl Overview
fhc project area geology is characterized by:
•      Predominantly volcanic pyroclastic (tuff; rock units in (he dam site and reservoir area.
•     Volcanic (basaltic) lava flow rock units in the dam site and reservoir area, suliordtnaie to tuffs except on higher ridges;
•      Volcanic 'basaltic) lava flow rock units throughout most of the command area;
•      Basement Rock units in the southern part of the irrigation command area;
•      Dolcnte dykes and sills intruded into basalt and tuff in the command and rcscA’oir
areas; and
•      Overburden deposit? of residual soil, colluvium, alluvium, river terrace deposit and recent river deposit
Several types of Tertiary and Quaternary volcanic (mainly basalt and tuff) bedrock outcrop throughout the study area, as well as basement rocks at the southern end of the Command
Area Bedrock is considered likely to be present at shallow depth along the length of the Main (Enat) Bcles river with outcrops often visible on the channel sides or nearby side slopes,
f urther outcrops occur along tnbuiaxy rher channels and forming the hills and side slopes of
the nver valley and edges of the Command Area.
The volcanic rocks are often covered by residual soil (rock that has undergone vinous degree? of weathering to break down to sod) and /or by colluvium (slope deposits of weathered rock / residual soil).
The rocks tn the upper catchment / vicinity ot the HEP scheme are tf achy tic tuff and basalt, with alluvial superficial deposits. In close nanny to the Dam Site and reservoir area there arc ridges of basalt forming the relative topographic highs in the surrounding area, whilst the Dam Site itself comprises thick units of tuff, lntcriayered with basalt On the nght abutment an unexpectedly thick sequence of superficial materials was found
In the undulating command area there arc two main types of geotechnical sods, the first is gTcy/black ven plastic days of vertisols (also known as black cotton sods}, formed bv
weathering, leaching and sod dev elopment The second is a red/brown clay or silt, often
associated with settlement areas and areas currently under rain fed crops.
The geologic units in the project area arc affected by several discontinuity structures These arc faults / lineaments, jomts and intense fracturing 7he major trend of faulting / lineament in rhe project area as traced from the prevailing satellite imagroes and on site field observation /
I’H IM SR04C Grutcch Pm 1 (1
4R
M -May-11Prwwntfh- typMr *!&*"(** Minty of lFdfrr&
Etfapd* A» Inftf** Dnun^c Ptyvrf
geomorphk evidences is generally NW - SE. NE - SW and NNE - SSW Ihis is in agreement
with the general regional structure Joints are frequently dipping at high angle (60 to 90
degrees)- The directions of streams and rivers courses in the area are considered likely to be
governed by maior discontinuity structure*. Unlike the Rift area, such discontinuity structures
are considered not to be active
5 j             Darn Sire and Reservoir Area Topography
The topography and geokagv of the Dam Site and Reservoir Area is shown on Drawing
LB/FS/GEO/10/02   (see   Figure   3-5).   Selected   photographs   of   the   dam   site   and   reservoir   area topography and geologv are included in Annex A.
The reservoir area is orientated NE SW and assuming a top water level (TWL) of 1.400 inxsl
associated with a large dam\ It is about 5.5 km long and 500 m to 1,500 m wide and mostly up
to 40 to 60 m deep in the centre of the vallev It is characterized by grade to steeply sloping
ndges and plain land form, with a major tributary, the river Krwarrmena entering from the
north
The valley bottom / flood plain is typically 100 to 200 m wide, with the river channel itself
incised 2 to 3 m and 20 to 30 m wide. Within the reservoir area the river occasionally is forced
through narrow rock gorges, and there is one significant gorge about 600m long located just
downstream of the confluence of the Kewaremcna and 2 km upstream of the proposed dam
site. This gorge was considered as dam site location opnon 1 though subsequently discarded in
favour of the proposed location (dam site 2).
The dam axis is onentated NW SE with a crest length for a large dam of about + 1.050m
between the 4-1,400 masl cuntours, The bottom of rhe valley’ has an elevation of about +1,330
mail, and here the over forms a straight section with an approximately 20 m wide channel that
is incised into the adjacent superficial sediments by about 2 to 3 m. There are patches of
exposed bedrock on (he channel sides.
The left abutment is steep, with bedrock exposed at the roe of the slope and at mid slope
Above the top of the crest is a small hill where there is more bedrock exposure This lull forms
a small bluff separating the main dam crest from a spillway area which is proposed to be located
in a shallow valley (saddle) about 250 to 350 m to the left (SE) of the main axis. ’Ihc minimum
elevation of this saddle is about 4-1,418 masl, therefore the spillway will require an excavation
of about 20 m (for the large dam options). The spillway chute is initially onentated to flow
southwards, but will bend to the right to flow westwards in order to rejoin the Bclcs River
downstream. The chute will be cut mtn a relatively gentle slope on the left side of the valley
For the small dam (Option D) the spillway would instead be cut into the left abutment slope
The  right  abutment  forms  a  relatively  gentle  slope,  rising  slowly  following  a  ridge  or  spur,  with  a slight kink or change in direction of the axis at about the 1385 masl contour so that the upper
I  "w  dam  &  rcrerviar  nze  opbutiii  are  considered.  Options  A.  H  &  C  arc  fur  large  dans  providing  «casoaal  storage,  while upthm   D   ta   for   a   much   <moiicr   providtag   only   diurnal   (24-48   hour)   *t»»r*gc.   Refer   Engineering.   Storage   Dam ^uplilrmcfltiry repnn
UB *=* Sftwr Gcottdi ftn 1 (1}
H -May- J [Fr*™/ drw.-Jfl.
* £'*»?«■
, fWjt,r & E,rS‘
E/tarf*!* Nir ImptM* m Dntn^r PwJ
part and most northerly pvt of the crest axis is orientated WNW - ESH There is a mbu^.
vaUcy  located  just  upstream  (NE)  of  the  right  abutment  crest  axis  that  may  affect  the  up5Ircjn. side slope design of the dam
5. /            Reservoir Area Geology
5.4.1         htmduJton
From  geological  mapping  carried  out  as part of  this  feasibility  study  the upper section  of the River Beles comprises the following geology (plate numbers refer to photos included as Annex
A):                                                                                                        . u
•      Most of the rounded hills and lower sections of the valleys comprise bedrock primarily of while or pale cream lithic or agglomeratic rhvolidc tuff, including at the roe, midslopc and top of the left abutment and spillway (plates 15, 16 & 22);
•      Higher hills, plateaus, steps and cliffs particularly ar the upper (northern part) of rhe catchment comprise basalt, with a slight dip orientation to the north (plate 17); on higher slopes there are often many rounded basalt cobbles and boulders on the ground surface, particularly of ploughed fields, indicative of outcrop, subcrop or relict basalt erosion in the area.
•      A basalt or dolente sill forming the lower gorge at the Dam Site 1 (+1,353) option, approximately 15 to 20m thick, with a paleosol! boundary with underlying tuff (plate
19);
•      A minor dolcnnc dyke cutting across die gorge at Dam Site 2 (-11338);
•      Residual soils with a tropical weathering profile above intact bedrock (plate 22),
•      Colluvial soils forming sleep slopes immediately below rock outcrops and cliff, often with incised stream valleys (phte 23);
•      Alluvial fans on intermediate slopes of steeper rivers and streams, with river terrace deposits in the floodplain, channel sides and slopes of the valley (plate 24); and
•      Recent silty clay and gravel river alluvium along the bed of the Beles River (plate 25).
Ground investigation was focussed on the dam site and further description that will be applicable to the reservoir area is provided in Section 5.5
5.42 Brdrwk Uat/r
The bedrock units found exposed ui the reservoir area are Tuff. Basalt and Dolente. A meeting with the Salmi Construction geologist. Mr Amanu on 4   May 2010 confirmed that the rocks in the upper carchmeni / vkuikv of the HEP scheme are trachvne tuff and basalt, with alluvial superficial deposits.
Tuff is the dominant bed rock unit exposed m die reservoir area It is described as: ^dtratt/y
th
rtntlgtottn^.t^uhp.ok togrry w/y hthie andpointy agglmfa, nntainingf,* tt
gruto/ii^fty^ti of nutty haiatt. It it ammoty tight to nMtratty uathtrrd and  fart tyhty
,jr
at
wu/Artrd. farytog/nn, maitivt to dottyjointtd I trtktmd Tl IF. Most outcro™ arc.
jLiuA.i t_ i ■ e .. 
, 
and blacks. At places the rock is found bang parti v silicified
r- °c cur as massive bed
Basalt is found in sonic parts of the reservoir area along river and stream beds and b desenbed as ftroag to vny strong dark slightly ^utbrrrd dost to Wry  faffy
c
*n y Ir u
UBJMSRCMCticmcch Pin 1 (1)
50
U-May-114/£riMpM. Mtorrty of fTtfrr fir fowgy
E/Av^jm NA br&fto» mJ Dm# Pflmf
ptacrj  Mn&riar  RASALT  The  mrxle  of  occurrence  appears  to  be  W  sills  within  ruff  host  rock  nx it appears tn be confined to discrete layers and inliers.
A small approximated 3 Co 5m wide dolcntc dvke is found exposed along the Bries river bank a
few hundred meters upstream of the dam site. It is described as t*ry r/™/j Art far A?
grarffd r/ijffrfff »tafberrd and e/owffjointed and if bafu/fh m ivarftofifton
Further upstream as (he formerly proposed 'Dim Site 1' area in the reservoir area there is a
steep narrow gorgr with good bedrock exposure. Here rhe bedrock comprises two distinct
units:
•      Lithic and agglomerate tuff at the base of the gorge, similar to that at Dam Site;
•      A basalt outcrop, possibly a sdl or infcdawring within ruff deposits, forming most of
ihc gorge walls, strong with closely spaced and often open fractures.
•      At the base of the basalt there is an approximately 200mm thick palcosod (plate 19)
that will be weaker and more prone to erosion and washout than the surrounding
rocks.
J./. J Sjffwfaia/ Dcporitf
The superficial deposits are nver deposits, alluvium and residual / colluvial slope deposits.
River deposits are found along  the course and banks of Belles River and main tributary  streams. It is generally described as: jiw/r wtrnntotidafed grry A? Art ijrr? wbb/y A/yp ri/fy sand) GRA 1 fLT- / Af (ww/ Zr rarrth ft? i.-oarrt, with tome frnr grained. and .mb rounded to jw// jdjmmW. q/ nrtxxd tirbotoguj.
Alluvial deposits are found covering the relative topographic lows and plain hud in thr
reservoir area. Il is a variable deposit, but a grnecal description is jtiff dark to dark and dark
brnwn rtiphtb, sandy ftightffgnnnlff fifty CLAY toi/ nra/maf of irry hrgb pAirterif).
Colluvial / residual soil deposits are found on the reservoir slopes. 'Ilicy ire commonly jtod/f
ivbbff GR/1LllL of nearnff ixuafttc rv^k Jragnretrfi and brgbff to iompktefy wrafbrrrd bed ntk units wrtit sow rrmnartt j-fnteiwr nawmd in a neatrix of stiff or :nry stiff dark grey to dark brown with yelfopt/b f/ai/lf graveff iinp SILT and graverifty CLAY.
Superficial deposits in the reservoir area arc considered likely to be mostly thin draping shallow bedrock on the valley ride slopes, with a typical thickness of between about 1 to 3 m_ However, al lhe Dam Site, one borehole (UBD04) encountered more than 30m of superficial deposits (river terrace sands and gravels, possibly mixed with colluvium) on a ndge on the right side of the valley (see Section 5.5), and therefore greater thicknesses of superficial deposits will occur in the reservoir area. In ihe valley bottom, gravel thicknesses of more than 10m were found al the Dam Site Area and can therefore also be expected in places in the Reservoir Area,
- h m SRi£M£; Geuwch Part 1 (J)
51
14 May-IlI-tHm/Daml). kfM- JF-H"?*
EffafW* NUt Impti" J«d Dnanaff Prmd
54.4 Stnufttn
There are num nujor photo-luieaments observed passing through and adjacent to the
Reservoir Area, mostly orientated SSWNNE. that appear to influence the form of valley,,
ridges, or straight sections of river channel Some of these lineaments are shown on the geological map (Drawing L'B/FS/ GEO/100/02, see Figure 3-5).
Major joints arc observed in outcrops of massive blocky tuft, some following the same
orientation and possibly responsible for somr of the topographic features No definite faulting
has been observed but there will be faults in the Reservoir Area Faulting is further assessed for the Dam Site Area in Section 5.5, and it is likely that similar conclusions can be applied to the Reservoir Area.
5.5 Dim Site Are* Geology
5.5.1 Summan of Porthole and Tnal Pit Ruk/Ij
The geological units found  exposed  and encountered by ground investigation in the Darn Site Area during the present investigation are outlined and summarised on ihr following drawings:
•      UB/FS/ GEO/100/02 Bries Dam Site (Ecological Map 'see Figure 3-5); and
•      UB/FS/GEO/2/04 Dam Site Geological ixmg Section (sec Figure 5-1 below).
A summary of the geological units found at the Dam Site and Reservoir Area is shown in Table 5-1 The geological units encountered tn the six boreholes and five tnal pus in (hr Dam Site Area are summarised in Table 5-2
5.5 2         3 of Gtophysta Ruultj
Two dimensional geophysical resistivity profile lines have been run in rhe Dam Site Area as four transects, shown on Drawing L’B/FS/ GEO/F/OI (see Figure 3-1} and locations are described in Section 3,6.4
The geophysical survey lines ire approximately along and perpendicular to rhe dam axis and saddle ridge where the spillway is proposed to br located A topographic correction ha* been applied during interpretation of the survey results, which applies particularly ro 1-inc 1. I-inc 1 also crosses the river where no data could be obtained (between chainage 6"0 and 715m). Here the interpretation rehes on software interpolation which should be treated with caution
The resistivity results are shown on Figure 5-2 to Figure 5-5 and arc discussed and compared to borehole rrsults in the following sections The geophysics report is provided in Annex G
The geophysical survey and borehole data have been combined with surface mapping to produce a schematic geological section along the dam axis (Drawing UB/FS/GEO/2/04 see Figure 5-1) An approximate chainagc svstem is applied to this long section, from left to right along the dam axis, with ch Om commencing at the left abutment ar *-1,424 masl clevari and ch. 1,135m at the end of the nghr abutment at +1,426 masl
I’RHSRtMCGrofcrh fan I (J)
52FrtlffW Dr^ron. H/fMt Uhifa. Afr®//?
E-V
Table S-L Geological Unit. aMheDam Sile andRweryoir Arcs
Name
Topsoil
Recent River
deposits
Description
Location and Commenti
Variable depending  on underlying  geology.
typically thin, 0.10 - O.44)m.
Along Belo River bed and banks.
Alluvium
(cohesive)
pound along the relieve topographic lows md
plain lands.
.Alluvium
(granular) /
River Terrace
DDeeppouosi:t
’Colluvium /
I Residual Soil
Highly
weathered
TUFF
Slight to 
Stiff dark red brown, black or
greyish ycllowjjrown silty CUA3
I nose unconsolidated variable
dark grey abghtly clayey sandy
GRAVE!, with cobble* and
boulders. With lense* of gravelly
da.s and iandi _______ _______ _
Firm to very stiff dark grey to
black slightly sandy slightly
gravely siity Cl AY to Clayey
SILT sod of high plasticity. < )ften
with desiccation cracks
Loose to medium dense variable
dark grey sandy GRAVEL with
cobbles interbedded with fine to
coarse SAND. Possibly clayey or ulty in places. ___ ________________
Stiff to very stiff dark grey ,
yellowish grey or reddish brown
very gravely silty CLAY to clayey
SILT and dayev GRAVEL with
cobbles and Ixjulders, often as
angular rock fragments,
W eak pinkish grey highlv
weathered bed rock recovered as
silty clayey GRAVEL with rock
tragments that are cobble to
boulder in size
moderately
wra t hr red
TUFF
I borehole cores
I Found mainly at the dam sire left abutment and
also in the reservoir area
Uaderfyiog cohesive alluvium, mixed highly
variable with thick sequence (>30m) at BIIUBD04 on nght abutment slope.  Possibly  fines washed out
during dnlling
Draping the side slopes of the dam abutments ard reservoir area Formed from the weathering and leaching of underlying rock combined with slope
processes
hound  ar  places  along  the  slope  of  left  abutment and reservoir slopes. Thin 2one» of highh
 weathered weak to moderately wrak tuff found in
fresh to
slightly
weathered
BASALT
Dolcnre dyke
l Moderately strong or strong
greyish pink to grey slight to
moderately weathered massive to very closely jointed lithic possibly
agglomerate (basalt and tuff
fragments) TUFF Occasionally
blue grey or brown. Sub-
horizonudly layered / orientated fragments in pbrcA______________ Moderately strong or strong dirk
blue grey aphananc and at places
vesicular medium to very closely
paired BASALT. Likely to be
very Strong tn places.
Strong to very strong dark blue
gm medium to fine grained
Exposures groerally big blocks with massive to widely spaced discontinuities, forming inclined pavements with onlr thin soil or cliff faces and hill
tops.
Exposed along some stream beds and banks and nn hill tops in and surrounding thr reservoir area Also underlying niff at left abutmenr and underneath alluvium ar nghr abutment Some basalts possibly sub mtnisivc sills, or interlayered
with ruff.__________________
Exposed on Bcies River bank
J slightly weathered medium to
closely jointed DOLERITF
I H F4 S«<M(. Geutcch Part 1 (1)
>4
H AU 11fY/fr*
HffapwK Ni&Jnrpffa jfffi I^n'n.dff /’m-ni1
.Vrrr/jX,’- af II j' iff <” farry
T able 5-2: Geotechnical uniis found in boreholes and tn a I p its id the Dam Site Area
Geological Unit
Spillway
Left Abutmml
Valley Bottom
Right Abutmenr
BHUBD7
UBDP2
BHUBD1
VBDP3
UBDPl
BHVBD2
BHUBD6
BHUBD4 1
UBDP4          UBDP5
BHUBDS
Sei It dark red brown gravelly day tv Mlr/cLai Alluv/CaHuv
------------- 1
n - 5 «5
|).t 0-3.00
0-2 80
0 - 3.00
IJ-15O
Red brown sandy clayey 
GRAVEL / graveOvSANl)
280-4 45
1.00- woo
1
IriiL'itKddLil variable Hilfs,
wundfc indgruvrb (criUluvium
nr itrrMc gravel)
O.lb 2.00
0-085
0- 50.00
0-1.80
1 50-250
(J -1000
I
RrMikid Kml >hiT grey 
himn gravelly *illv di\i
5 85-7.95
O.85-2UO
t. 80-200*
—
Mod. srriMig mini, wntheri’d
pink or blur prcF lithrc J UIT
7 95- 16.35
26 65-28.55
I)-3.10
4.45—7 JO
IL75 - 13.70
t
1
Mud wrong io jtwmg fresh
tr> *t wralhcrrd funk ur blue
PJlt hducTULT (upper layer?
1635-19.55
23.10-26.65
■
5 10 — 13.80
7,30-10.60
Very wt-.-tk hi wi-alt highly 
WLjalll£*ttd / dlcrrll TUIT
13.80- 20.00
10.60- 11 75
Strang tiedi pink «j< blue grn T1 'IT -IriwiT Jarer,
26-25 65m
13.70-50,00
1
Strong Jighrly weathered
BASALT
19.55-  20,50 21 80-23.10 28.55-   J5.00
25.65-34.50
Strong io very  wrong frcdi
BASALT
34 50-38.70
1
10110-
15.00
Final depth
35.1X1
100
38.7(1
2.00
3.00
50.00
10.00
30.00
200
250
1500
J
Nun* (I) oplurahur hole ccijuenre w pmerallr kit lo riglu akingthm xvu 2j value* ire drpih below ground livtl tn mrters. ;3) *11* UBQP4 Iriwest iitiu may lx terrace gravels
L'bl ISRIMCGurtcdi I'arr 1 (1)
55
14-Mnr-l IFn4r»rtZ I>rwo»Turr.-     if EMjitfua, Muvrtr)
«*“ Bw^
Ltbitpjn Nj*
Dr^nj^t J'njjtr:
Figure 5-2: Resistivity section ljne 1, along the dam axis, view looking upstream Upper Belts OaR Axlsili
Model tesistiwity with topogi «phy lEleualion <^«rwLluii 5 RM3 errvr - 11.6
1081
139
13804
1370-1
13604
13b 0-
13K0-
1306-
1328-
■ MB MB M MB <ZZ1 CT3 C=J tdZJ ddJ HE
1.00 a.OB 5.00
131
10.0 30.0 50.0
in uha.n
ate
Unit
----- 7K/pM.-a 
.\fraufTi »t ITj^rr f~ I'.nn^
Nt* [rrrfjfron jvti Drjrjtqfr Prw.r
ire 5-3: Resistivity section Liar
Model resistivity with topography Elevation iteration 6 RMS error • 9.7
to dam axis along bottom of vallev
Line-?■■■
135B-|
o.o
13*0-
1335
1330
1325
1320-
1315-
T. o" n" ™3«.O
Nfl/f.’ i^j/rraw fltf sidt
240
100
EZ3 ZZI
50.0              100              30«
Resistivity In oh«.n
Unit Electrode Spacing - 5.00
UBH SRWCGc<Jh-d»l*art I ;i)
14-Mav-ll/'rdtrn/ lithttpja N/£
9f
.Mim/TT) tfTjtrr <*• Ewip
Ornitt^r P*w*T
• *Rurr 5-4: Rcturivity section Line 3, Along saddle ndge (Aerons spillway channel)
A’tf/r. wt»- looking i^rfTTdfff
__
/ri EJbrtpfu. Mtvjtrj tflFaftr
£/fe^ii>* N>£                   WPm^ Pmr.7
j-y J             /_<// /l^wAwflt/ fd/jprpxiwj/f ribabfaqr 0 — 294 m)
'rhe  left  abutment  is  steeply  sloping  and  is  covered  and  underlain  by  predominantly  mN bedrock, residual soil and colluvial slope deposits
Superficial deposits irr present in two areas of the left abutmrnr on [hr upper slope and lower slope, separated by art area of bedrock outcrop ar mid slope. Trial pits UBDP2 and L BDP3 intersect superficial deposits on the upper slope to depths of 2m without encountering bedrock, although at I 'BDP3 residual soil (completely weathered bedrock) is interpreted below lllbm depth suggesting rhe bedrock interface likely to be ar shallow depth below the bottom of the
trial pit.
The residual sod unit was recovered in the hand dug pit as jjrtdy /wiiMN /g itww d^&rGR.4P71L.
jmiArijh tfty foyrifawifh gny //Zry
Overlying die residual sod, and encountered from 0.1 Bm to at least 2m depth al trial pit UBDP2. is colluvial slope deposit composing rflrrc /Try iAkf j/Z> a>My GR.4 I BI- mA stiff Jftii C1~4Y to dbyry SILT The cobbles and gravel are predominantly basalt rock fragments possibly obtained from differential erosion of the lithic tuff host rock, releasing the basalt fragments upon disiniegrjrion / decomposition, or from relic basalt outcrops at higher elevation, or reworking of immature river terrace deposits The lower slopr of the left abutment is likely io be covered by thicker superficial depts its, including nver terrace deposits and alluvium as well as colluvial soils.
Bedrock is found exposed at the top of the slope forming a small hillock between ihe lett abutment and the spillway, and at mid slope where borehole tJBDOl is drilled. It is modfnrtrip
Strong io rtrv/rggrvwi) pink to gm and 
flrffjriffvgmnttj bring bojaJ/J /fight ft?
umrfbffYii ararm* isiarfi jpaad io cfor/yfaria/nd JUH  On ihe surface it forms smooth
r
sloping pavement, massive or widely spaced open joints, with rounded boulder appearance
Based on borehole UBD01, which has a total depih 38,70 m and was drilled n midslope on the
left abutment where rhe niff outcrops, the tuff is encountered from surface to a depth of about
25.65m In ihe borehole a small amount of basalt core is recovered at about 19,55 to 20.50 and
21 -80 to 23.10 but it is nut dear if these are thin layers / iniruirre sills or large agglomerate
boulder* of basalt witbm the ruff host rock.
The pyroclastic tuff rock unit ar places is partly silicified and altered id chert and with
development of silica quartx In particular, a zone of more highly weathered, weaker and mare
itacrured tuff was encountered between about 13-80 to 20m depth. 'l"hc tuff appear^ to be
softer with a less ccmerucd matrix and less basalt bthic fragments, suggesting there ia variable
layering of several pyroclastic events with variable composition and strength.
Joints  in  the  tuff  are  variably  orientated  and  sub  -  horizontal  to  vertical,  right  to  open  with  same being with clay infill.
tJBP4SRiHCCHtn«bPinl I)
H May 11Mru: Demoaatx
Afrwm U'iftr & Eongf
Eihmfxji Nib Mny/*« wrf Draoagt Pny<v
From 25.65mts co the bottom of the borehole at 38 70m, the rock encountered is .r/nrag /0
/W? dark btubh ^ to black fresh to jfybffy withered close to wj
04 X4l/
Based on surface mapping, the basalt is interpreted to be an intrusive sill-type structure, but an alternative interpretation is that there could be micrlayenng of tuff and basalt with potential fOf paleosoil development in between. No evidence for paleosoils has been found in the Dam Site Area, but this is a potential design hazard that should be investigated further during detailed design ground investigations
Basalt was also encountered at a higher elevation at the spillway (BHUBD07) Preliminary interpretation assumes this to be the same unit, with an inclination, but potennaUy there could be more than one basalt unit, or the basalt c ould be layered sub horizontally, with a fault located between BHl’BO? and UBD01 with downthrow to the NE.
Similarly, downslope, no basalt was found outcropping or within 5(>m depth of borehole L‘BD02 ar die bottom of the valley, again suggesting either an inclined sill, or potential for another fault betwren UBDOI and UBD02 with downthrow to the north.
The geophysical survey of the left abutment has identified the area of high resistivity outcrop (station numbers 820 to 940m on Figure 5-2), plus subvrriical low resistivity features above and below (e g. station numbers 820m and 940m) It is nut clear why there arc so many subvertical features in the geophysics, and it could be processing errors, or could represent fault zones. These features should be investigated further at detailed design *tage
5.5.4          ( entrul Riner I alley (approximate chamaft 294 - 4i4m)
The central nver valley section of the dam axis is characterized by gendv sloping topography and floodplain The site is covered by superficial deposits of mainly alluvium and nver deposits. The underlying bed rock is partially exposed in the banks and bed of the river channel, with greater exposure occurring just upstream and downstream of the dam sire axis.
Two boreholes (UBD02 and L BD06) have licen drilled in the central nver valley area, both on the left side of the nver Borehole LBIXJ2 has a total depth 54hn, and is located as close to die nver channel as was possible due to vegetation, about 10m from the top edge of die left nver bank. ‘Dus is at the lowest elevation of any borehole on the dam axis and therefore intersects the lowest strata of any borehole beneath the dam Borehole l*BD06 was dolled approximately 110m downstream of the proposed dam axis in the centre of an area of farmed floodplain Tnal
pit LTBDP1 was excavated to 3m depth on the floodplain about 65m upstream  f borehole
o
UBD02.
At borehole UBD02  intact bedrock was encountered at 4  75m depth,  consistent with observed
outcrops in die nver channel and bed The rock composed lithic tuff fo  the full j
f
cnr
L f h
f
I R H SR04C C .corcch Parr 1 1)
60
14 May 11Dww*^*'
**              AfeMTr/VT ^IFafcr ^F.bwj;
E/fa$w*» N'*                   Pnrwjr Pw
zones or livers of light bluish grey tuff, and a layer from J 0.60 (oil. ’5m of very weak to weak highly weathered friable closely jointed rhyolitic TUFF where die lithic fragments arc predominantly (90%) of white tuff.
The tuff encountered in BHUBD02 is consistent with surface exposures in ihc river channel However iImj found in the nver channel close to the dam axis and iusi upstream, is a doled re dyke that is described as: jfrMg ft? j*n tfns?r< dark b/xtibgrry jtybffy vea/hmd <'hje /tJ 
foitftfd
A? fint graifrrd 9*ak/y tWtarfar/9 
DOUEIUTE-
Alluvial floodplain deposits are found un either side of the incised river channel, and at
borehole UBD02 comprise 2.80m ol day overlying a further 1.6 5m of gravel. Ar borehole
17I31TOG there is 3m of clayey silt overlying more thin 7m of mixed sand and gravel. Bedrock
was not encountered to a depth of 10m at bntehrde UBI>K». At trial pit UBDPI 3m of sandy
silt were found
The upper layer of cohesive alluvium is generally described as r/^flrwry trifidark rrddtrt* bnirri
jfighffy jjtfdy wn rity C1--1Y tfr I'Zjrjfl 52LT m/* wraftwra/ rwided grin*/ A3 Aw/dw of bata/f.
The underlying  granular alluvium units arc generally  described as hwe.  pesjibk  trndtmte/y deme fight
Irnjvfs iifiitgTTr mttrhfdded Offd gf
i^<y Jaadf_fim A? nwnrf FHfirtilifsdft/ to .uMffdfd
6FL'11  TfL  with  oaariMatMtj.  More  Standard  Penetration  ‘fests  (SPT's)  arc  required  in  this horizon to confirm the density.
Towards the left side edge of the alluvial floodplain there is a stepped feature of about 1-5 to
2m height, indicating that river terrace gravels are also likely hi be present. At the base of the steeper abutment slopes, it is likely that I here will be increased thickness of colluvium slope
deposit.
Geophysical survey results along die dam axis (lane 1, Figure 5-2) in the central valley area are difficult to interpret, wiih in apparent slight decrease in resistmty with depth, thai may be due to underlying groundwater or due to more fractured poorer quality bedrock, as well as apparent vertical geological boundaries that could potentially represent faults. Borehole UBD02 is located at about station "25m on a subverheal boundary, making correlation to the geophysical survey difficult Borehole UBD02 is also k>catcd at about station 125m on resistivity line 2 in an area of relatively higher resistivity.
On line 2 (Figure 5-3) the top part of the section covered with parches of very’ low resistivity occupying the top 5 to 7m is probably attributed to clayey alluvium. Towards the northern end of rhe bnc (north of biadon 2441m), the lowest resistivity values arc observed having thickness of about 2t)m, which may be a thicker sequence of clayey alluvium and should be investigated further al detailed design stage
LB 1-4 SRiM-C; Grotrch Pin 1 -|)
61
14 May. 11Ful r* Paw.no.-
•/&****
< V*" f E*rrp
lisb"f*n NUr lwt>" a»J Dwaft Prr^r
5 5.5          Right Abutment (approximate ibamage 454 - 1,205m)
The nght abutment is characterized by a gently sloping ndgt that is covered by superficu]
deposits with no bedrock exposure. The nearest exposure is in the stream bed at the bottom of
a tributary valley just upstream of the dam axis, where there is a small basalt outcrop (Draw^
UB/FS/GEO/10/02).
Two boreholes of depths 30m (UBD04) and 15m UBD05) have been drilled at the nght
abutment and two trial pits completed, with I ’BDP4 co 2m depth and UBDP5 to 2 50m depth
Only borehole UBD05 encountered bedrock from 10 to 15m depth All the other holes
terminated in superficial deposits. Drilling was terminated at BHUBD04 due to technical
problems drilling through superficial materials at this depth In addition, the drilling and
sampling method may have washed out finer materials (silts and days)
The material encountered at borehole I'BIXM is interpreted to be over terrace and colluvial
slope deposits It is a vanable mtcrbcddcd sequence of the following lithologies
•      Brown or ryr, randy fine to atone angular to mb rounded f?R.41 "HL with occasional aobb/ej and possibly clayey and silt) in places. growl predominantly of basalt;
•      lzrf) stiffdark brown nip CLAY; and
•      Dark brown and gm gram h silt) SAND of tunable gram st% between fine and coarse.
The beds arc grncralfr 0.5m to 2m thick, except for a thicker unit of chy from 9.6 to 15.5m
depth At borehole UBD05 a similar sequence of vanable sands and gravels was encountered to
10rn depth, but with no day unit. SPT N values in borehole UBD05 (26 and 42) suggest the
ma renal is medium dense or dense.
The bedrock unit encountered m UBD05 from depth of 10m to 15m is strong to ver, strong black sbgbtfi weathered aphanatic (10 - 14.40m) to wsimlar I scoro.ro us (depth 14.40 - 15.00) close to wry chsefy
jointed BASALT. The vestdes are partially infilled with silica
The great thickness of river terrace / colluvial deposit found at BH LBD04 was unexpected, as there is no indication of such a thickness from surface morphology. The geophysical survey line 1 (Figure 5-2) shows two distinct resistivity responses at the nght ibutment
For the first (upper half) of the abutment between geophysics station 0 and 400m there is dear two layer structure with the top pan characterized by low resistivity of less than 30 Ohm-m has a uniform thickness of about 12-15m, which based on BHUBD05 (located at 225m) is superficial sands and gravels The bottom pan ts characterized by relatively high resistmn response of 40 to 300 Ohm m, which is likely to be fresh and massive rock, possibly basalt as found at BHfBD05
The second (lower half) of the abutment extends trom station 400 m thr u i
6 0. In (his area, no dear layering is observed, but the profile is generally dominated b ]
_ 
, . 
it
l
a af Sitton
resistivity response of less than 30 Ohm-m, either indicative of thick superfi i highly weathered and/or fractured formation, lhese low resistivity zones ve thick at places (e g station 460-500m and 530-590m). Borehole UBD04 i<
^ated at abour
UBH.SR04CGciwhP.irf 1(1
14 May 11bzrtffafc''
^F/Awj^a. AkaHtff tf Jttr i-
f'W”" Drjr*^
station 445m and docs not correlate well with the geophysical survey, There is no obvious geological ex plana linn for the geophysical result tn this area, but potentially the lower halt ol the abutment could form a thick sequence of river terrace gravels, or there could be some form of fault control creating the near vertical changes m resistivity.
5.5. £         Sptifowy zl rrtf fl WdfrJ
Hie proposed spillway site for the larger dun options A to C is characterized by saddle like land form It is covered and underlain by an overburden deposit and bed rock units. Bedrock (tuff) is exposed on and forms the adjacmr hill to the west that separates the spillway from rhe dim (see Section 5-53). The slope to the east is covered with basalt boulders, suggesting that the htll to The east may be composed of basalt, although there is an outcrop of tuff to the southeast
The land in die saddle is farmed and the soils appear to be darker and more plastic than the rest of rhe dam site, potentially indicative of highly plajnc swelling vertisols present in this arra where the drainage is poorer due to the shallower gradients.
There  is  an  exposure  of  tuff  in  the  slope  just  upstream  of  the  saddle  area  where  gulley  erosion
has removed superficial materials. Here it is described tu wderutefi
cbjfto mtdwmjwifai Mteaitdpowbfy agtoniftrafa TLF1T . Tins suggests there is a weathering profile to the tuff benrath rhe saddle area
wdmiff to typA
7
One borehole flJBDO?) was drilled to a total depth 55m in the centre of lhe saddle Hie two
geophysical survey lines 3 and 4 cross each other at the borehole local ion. The borehole
encountered 5 85m of irjff dark grey slightly gravely silty Cl .AY of high plasticity., interpreted to
be a vrrusol deposit formed from chcrrucjd leaching, possibly with some slope wash deposits.
From 5.85 to 7,95m is completely weathered bedrock (residual soil) recovered as grey gravely
silty CLAY, with rhe angular gravel fragments predominantly nf cuff. Intact bedrock is present
from 7.95m and io the bottom of the borehole forms a sequence of variably weathered tuff
overlying ba sail and interlaycrcd with has air intrusions or containing basalt boulders.
From 7.95m to 28.55m thr materia] encountered is generally described as /votirnrttfy jtounp Jo
pfxk jQgto to nwfcrutofy uvj/Zvrrddwe4 pinftd              andpvfribfy afthtwruti; TUFT\ 77r
art baja/f and tttjf, Jcrntf art rtainrd ortMtf bwn. aprn to fyht. ntujfh ntb-mfita^ JJfb-
fan^ynfai and aJ 45'
Strong dark blue grey to black aphanitic basaltic rock is encountered from 1935m tn 20,50m
and from 21.80m to 23.10mts, This is probably finals of basalt boulders within the tuff, but
could alternatively be thin intrusions of basalt
Below 28.55 to the base of the borehole at 35.00m is Jfrv^ dark bhrirbgrry to blark J&gbfty ^ta/hmd jQfHfrdaphanafa RzUzlLl’ Joints art 45* to r*b tKrttcaf, and toatod irifb quart?
Borehole UBD07 is located at station 75m on resistivity  line 3  (Figure 5-4) and al station 200m on rcsistiviry  line 4  (Figure 5-5).  1  jhc 3  identifies rhe highly  resistive tuff outcrop at the western end of die spillway but docs not identify a clear bedrock boundary across the spillway or at
■ h I'4                Gruifdi Pari I (I)
63
H May-11f-r*™.' fWxrun, R^»Mr ,f Ert"f“ M‘*urn 'Wat'r f E-r^
Ethtpw* N»£ Im^afK. and Driver Prvrr.1
BHl*BDO" It is not clear why this is. hut potentially rock mass quality becomes poorer t(J  (]] east
] jne 4 shows a dear layered sequence following the slope with higher resistivity units bdou about 10m depth Although this docs not correlate exactly with BHUBD07, it suggests that t|
top of bedrock util be at a relatively uniform depth in the direction of the upper pan of the spillway slope / spillway excavation.
5.5.7 StHtdlfTT
No faults are observed m outcrop and none were encountered by the boreholes, but photo-
lincarncnt interpretation of the morphology combined with the drilling and geophysical rcrult
suggest that fault? may be present beneath the dam site, and are likely to be orientated SW-Nl approximately perpendicular io the dam axis. The following structural relationships arc not
drar and require further investigation at detailed design stage:
•       Basalt layers subcrop at different elevations tn borehole UBD07, UBDOI and L’BDd
but there is no basalt exposure on the hill side and basalt is not present in borehole
UBD02 The basalt may be inclined, following the topography or if lying horizontally
could be the same layer with fault tlirows between boreholes,
•       It is not dear whether the lithic ruff that is so prevalent on the left side underlies
superficial deposits on the right side If it is absent, this could be due to a fault in (he
centre of die valley, and
•        There  are  several  vertical  boundaries  observed  on  the  resistivity  line  1  profile  (Figure 5-2);  if  this  w  not  due  to  processing  problems  then  the  most  likely  explanation  is  that these represent fault zones of lower resistivity disturbed / broken rock
Additional  drilling  investigations  targeting  the  features  described  above  combined  with  seismic geophysical surveys are recommended for the detailed design stage
UH F4 SRCMC Grnirch Pxrt 1 (I)
64
14 Mav 11It&W mi Pnugr Pr^nfT
COMMAND IRRIGATION AREA GEOLOGY
introduction
/So  overview  of  the  geology’  for  all  of  the  protect  area,  including  the  command  area  is  provided in Section 5.2. This section describes in more detail the geology of the command ncn
6,2 Phy*fog**pty and Sod Survey
The  following  section  is  based  mainly  on  extracts  from  the  Supplementary  Report  SK  01_r\.  Sod, Land L'se and Suitability*.
fhe Main or Efiat Belts river originates from the face of an escarpment m the high mountain range at about + 2,250 masl separating the Enat Beles basin on the west side from Lake Tana The Enat Belts begins where thr tributaries of rhe Kassan and Jehana rivers join, whereby the latter receives flow from the outlet runnel of Tana-Beles hydropower scheme draining I .ake Tana. The Abat Belrs rising in the east ha*? created its own alluvia! Ian, and joins the Enat Belts in rhe middle of the Command Area.
The relative toprugrapiuc lows and plain Land is piedomiruuiliy covrred by soil overburden material (Quaternary deposits) and to certain extent by the basalt and the basement rock outcropping units. The thickness of the Quaternary deposits is commonly less than 5 m and is formed by a process of weathering, erosion and deposition
The Command Area comprises a slighdv concave alluvia] and colluvia! basin plain of the Upper Belts River The plain is narrow in the north where the river spills out of the mourn arris and ihen qiuddr broadens southwards to about 40 km at its widest point- The plain is cut across Ternary sheet basalts in the north and Basement low-grade metamorphic sediments in thr south Since its formation the plain has been covered with (pre-) Pleistocene alluvial and colluvial sediments deposited as coalescent fans bath by the Upper Bcles. Rjvrr and by its tributary streams, particularly those from the east The rivers arc now incised so that these fan deposits are being actrielv eroded.
Dissection is greatest in the south-east of the Study Area, south of the Chankur River The Bula
- Chankur interfluve is also strongly diaiectcd. Compared with the land east of the Beles River the land to its west is relatively little dissected because there arc few tributaries of any siy.e or Bow, Large, gently sloping surfaces of the original alluvial plain remain.
Original plain surfaces remain as gently sloping land with deep, strongly weathered red clay soils on higher pans and with Vertisols on ilighdy lower slopes. The soil survey finds that deep cracking montmonllonilic days, KrrttroZr. are lhe must widespread soils in the Study Area, covering about half of the area, 68,279 ha They occupy stable lower (relative to rhe red clay soils) topographic positions, mainly on gentle slopes. Deep reddish days (NjJntfZr and L^r^/r developed mainly from old alluvium or underlying basaltic rocks cover much of the gently sloping, comparatively little dissected upper interfluves. These soils cover 14 % of The Study Area, amounting to almost 20,000 ha.
UHP4SRWGeatechBinl (])
65
I4-Mfty 11Vttirrji
Effapia. MtWf.V of u atfr &E*ip
IttvofiM X'/Jr Im^fTo/t mJ DrwHdff P/yhT
Brownish, weakly developed soils (Cambisols) mainly associated with eroding land cover $• the area, 6,810 ha. Ven shallow and/or ven* stony soils, Lgpfmb. sods of dissected v U^.
a
systems and hills together cover almost 42.000 ha, or 31% of the Study Area Virtually >U  p
o
these sods are unsuitable for irrigated agricultural development.
Rainwater runoff results in the formation of nver and stream deposits along the course and banks of the prevailing tributary streams and m en. Such river deposits comprise clayey sandy, gravely, pebble and cobble size materials of different composition.
Typical views of the Command Area arc shown in Figure 6-1.
Figure 6-1: Chanko river (top left), View of Derehay plain (top right), cropping upstream of Fendika (bottom left) and on Work Mcda plain (bottom right)
In summary, three broad types of land lorm exist in the Command Area:
•      Rough, incised alluvial fan areas m the north-east (Enat Bcles). and on a srnallrr scak in die far cast (Abai Beks);
•      Broad, plain areas of land in the north west the Derr bay plain) and central part AX erk Mcda plain), and
•      Narrow ridge lopogiaphv in the southern areas.
Current land cover comprises long (elephant; grass and thorny bushes interspersed by pockets of dense acacia and broad leafed trees that are remnants of forests A considerable parr of the project area is used for farming growing mainly cereal crops and sesame. Most land use is by smallholder farms but there arc also small / medium sized commercially managed areas In
UHHSKfNCCknrech Pm I 1)
66
14- May 11.W/er/fp tf'W j' fe^ &
/jtartMW Xdf f flwur.w tfW                    Pi^At
addition  the  land  is  used  For  livestock  grazing  The  current  ratr  of  deforestation  and  doting  of bnd for rain-fed firming is high.
j             Brdrack Lfafr*
£ J. /          B jsrmfftf Rptk Uxitf
Outcrops of basement rocks are found at the southern end of :he main canal alignmcnis on
both the left and nght sides (Drawing LB/ES/GEO/HJO/OI, see F igure 3-4). A tentative
boundary between Tertiary volcanic rocks and Precambrian Bnsernertt rocks is shown on this
drawing*
The units are highly  variable in composition,  texture and mode of occurrence with no  visible stratigraphic relationships between them,  suggesting  that the underlying  rock throughout this area will be complex and variable Descriptions of the outcropping units are:
* Strong variable dark grrv slightly weathered niassn e blocky QI 'ARTZF IT'. Exposure has been encountered towards end of the left bank canal in the command area. Mode ol occurrence is as big blocky and boulder like forms.
• Grey medium grained moderately weathered medium to closely jointed QUARTZO —
FE1.DSPATI FTC rock. Discontinuity planes arc found being filled by quartz veins that arc sugary to glass v in texture. The outcrop has been encountered towards the end of the right bank canal in the command area
• Grey to yellow greenish grey medium grainrd moderately weathered and schistose quartz-sericite-chlorite SGI 11ST 1’olunons dip sub vertically to vertical
rf.J.2 Tertian' I eixnuc Rjv£r (BosaksJ
The vokamc Lav a flow rocks found m the Command Area arc mainly basaltic (basic) in composition, but there arc occasional rhyolitic (aadic) rock units Basalt is likely to underlie a considerable parr of the Command Area, but exposure ls limited due co the topography and presence of superficial materials. The pyroclastic lulfs associated with basalts in The Dam Sire and Reservoir .Area were not found in the Command Area.
Outcrops hive mainly bcm found at the nght bank off-take weir site and along the right side main canal to Jawi (Fendikaj.
The basalts arc dark bluish grey CO black aphanaTK to vesicular / ainygdaltndd Vesicles size ranges from mm to centimetres. The 412c of vesicles may be a function of the Less viscous nature of dir mdt, which allows the bubbles (o expand more readily before the magma solidifies. and of the higher rem pc ramie of the basaltic extrusions, which allows a given amount of gas to occupy a greater volume. Because of the relatively greater ease of floatation of gas bubbles within basaltic magma bodies, die tops of basaltic flows as well as some ejecta arc commonly highly vesicular.
1 -H 14 SKlMC GroEech Part t (I)
GT
14-May-UFtdtnl
cf Etbl^a. Mhutrf iWeltr & E»rp
Ethiopian Nr* ImgonaK J»d Dndaage Pryra
The amygdales are silica quartz in composition that is amorphous to cry stalline in texture Aj
phees such amygdala are found being well crystalline bi-pyramidai to pyramidal and majn)v
amorphous), fresh to highly weathered and massive to fractured / jointed Fractures and
found affecting the rock unit are mainly attributed to the cooling effect, but with some
secondary tension pints
A general description is: jM/ to *0 strong slight to modrrateiy weathered dark, wstaslar to amygdala^ (amygdales being welhrystailine and amorphous anart^) massne and medium to do stly jointed BASALT.
At the weir site an outcrop is found exposed towards the left bank of the river with major
discontinuity structures attributed to depositional layering of flows at different phases
Furthermore, certain rock units arc found being affected by jointing. These are mainly two sets dipping 60° to 85°. medium to closely spaced, rough, planar, open ffrequently 10 to 50mm that
are partly infilled with clay.
An acidic lava  flow is found exposed forming  ndges in the area  towards the central pan of the left bank canal route It is desenbed as: grey sight to moderately weathered matrive to widely Minted fine
grained RJ / YOUTH
6.1J Doirnte tnlnunn rock
(lutcrops of dolrntc. interpreted to be intrusive sills and dykes, are found over a considerable
part of the Command Area, and in particular in die central to lower pan of the Command
Irrigation Area on the right side, in the vicinity of Pam There are also exposures at certain
pans of the bed and banks of the Bclcs Ris er, including al the right bank off-take weir site.
The rock is desenbed as to icp strong dark grey slightly weathered, massive to dose/) somted medium to fine grained £X)U:R/TE.
At the weir site no definite trend was observed to the jointing and it was found to be discordant to die surrounding vesicular / amygdaioidal basaltic rock unitFalW
Afjwffry ylFrfr- c*-H«rp
4          SuperfieM (Geotechnical Soil) Unite
6,4 f        Tipsorl
Topsoil is found throughout the Command Area and varies in thickurs* from about 0.07m ro 0.45m. Il as genet ally described is a stiff dark gny/ brown gravelly silt/clay The exploratory boles in which topsoil was encountered ire summarised in Table 6-1.
Table 6-1; Topsoil Occurrence in Cotomand Area Exploratory Hotel
Exploratoiy Hole
Depth (mbgl)
Topsoil Thklmet* fm)
HH (JPBSR 01
Ona to 03m
0-30
BH UBBSR02
0m to 03m
030
TPB 4
Dm to 0.17m
OF
TPB 8
Dm to 0 07m
0.07
TPB 10
0m to 0.27m
0.27
TPB 11
Um co 0.18m
0.18
1TB 19
0m to 0,35m
0.35
J’PH 20
Um co n.3m
030
TPB 29
(Im |c 0.1m
0.10
I PB 30
Dm to 0 25m
0.25
TPB 32
CJm to 0.34m
034
TPB 34
Dm to 0.4<n
0.40
TPB 35
0m to 0,1 m
0.10
TPB 38
Um ro 0.45m
0.45
TPB 4U
Urn to 0.2m
0.20
•1TB 41
0m to 02m
0.20
TPB 44
Um to (J. 14m
0.14
TPB 45
Om to 03m
0.20
TPB 47
0m to 02m
0.20
TPB 49
Om to 03m
030
ITB 52
Om to 03m
0.30
6.42 I 'trtiMii
Vertisols cover most of the Command Area  and are generally  found in rhe lower lying  areas Dus unit underlies parts of the alignment of die Right and Left Hank Main Canals as wTcli as secondary canals is indicated on Drawing UB/ES/GEO/100/01 (sec Figure 3 4).
The vcrtisnla are generally described as a stiff fo wrj sf/ff ir^rk ft Jknfe jpry / 6rp»ir jiffy jfyMy
i-^r> <?J ivry high fo rxATwir^ Af/A/Zv/zn/y, iw'/A sbfty jliekm sides thte fo fie             and .rn^f/rn^ properties oj the wfernti. ITic vertisols often have deep desiccation cracks
.The exploratory holes in which the vertisols were encountered ire summarised in Tabic 6-2. 1 he unit typically rxcccds more chan 2 tn depth and the maximum thickness that has been
encountered is greater than 3.97m {TPB 11). However in three of thr exploratory hales the vertisol thickness was 1.0 m or less
f
L < M SR04C Gcnirch Part 1 (1)
69
14-Aby 1JftU
•!
f' *"
Effapw Nib frnpti" c*d Dr***t
T1abablele60--2:4: Vycerrutissuoli  Occurrence in CommArea Exploratory Holes
Exploratory Hole
Depth (mbgl)
Vcrtiiol Thickness (m)
TPB 5
Om to >2m
>2.00
TPB 6
Om to 0.85m
0.85
TPB 7
Om to 1.2m
1.20
TPB 9
Dm to > 2.68m
>2.68
TPB 11
0.18m to 4.15m
3.97
TI’B 12
Om to 2m
2.00
1TB 13
Om to 0.63m
0.63
TPB 18
0m to >2m
>2.00
TPB 20
0.3m to >2m
>1.70
1TB 21
0m to >2 45m
>2.45
TPB 22
Om to >2.7m
>270
1TB 23
0m to >2m
>200
TPB 24
Orn to Im
1.00
TPB 28
Om to >2.3m
>230
TPB 29
0dm ro >3m
>290
TPB 31
0m to > 1.65m
>1.65
TPB 35
0.1m to >2 8m
>2.70
TPB 36
Om ro >2.85m
>285
TPB 37
Om to >2 9m
>290
TPB 41
0.2m to >26m
>240
TPB 43
0m to >2-4m
>240
1TB 46
0m to >2.5m
>250
TPB 53
0m to > 1.95m
>1.95
6.4   f faddish Rrvw Stif/ CZ/) (fajubsal Soil)
The reddish brown silt/day unit is generally found in (he areas around settlements, i.e. around Jun, Pawl. l.dgel Beles, Werk Meda, and the villages between I’awi, Gllgri Belts and Werk Meda, as urD as tn areas currently firmed with nun fed crops This is likclv to be a function of these areas being slightly higher ind better drained than the vertisol areas
The unit is generally described as a stiff to trry stiffest, „lt/ ^, tsanstosvffy
c
m
ttd to bt
fTOPtl^
It IS interpreted to be formed pnmanh as a residual soil of completely weathered basalt rocks.
The exploratory holes in which the reddish brown sdtv dav sod is encounr^.j
m Table 6-3. The unit typtcaDv exceeds more than 2 tn depth and the maximum depth that has
been encountered is greater than 9.65m (BHB 01) However in four of the ex ) the vertisol thickness was 1.0 m or less A significant thickness of this
be excavated during construction works for the nght bank off-uk  weir
° *
c
UH I 4 SR(MC Gcorrdt Pan I (Tz
70
N-May-Hji/'lFdftr & Earr^
HfAwp"« W J™ifr<7 * attJ &***&  >
J
Z7
T a ble 6-3; Red Brawn Silly Chy Soil in Command Area Exploratory Hole*
Exploratory Mok
Depth (mbgl)
Thicker** (m)
— *------- —--------
BH UBHSR DI
0.3m to 9.65m
9.35
BH UBBSR 02
0.3m to 7.6m
7.30
7TB ID
0.27m ro >2.6m
>2.33
TPB 11
4.15m to 4.35m
0.20
TPB 1?
Dm to > 2.33m
>233
TPB 19
0.35m to > 2.55m
>230
TPB 27
Om to 0.2m
0.20
TPB 30
0.25m to >2 5m
>125
TPB 32
0.34m io >3m
>2.66
TPB 33
frn to 1.25m
1 25
TPB 34
0.4m io >3m
>lfiO
TPB 38
0.45m to 1.4m
0.95
TPB 39
0m to 1.5m
1.50
1TB 40
0.2m to >4m
>3 80
ITB 44
0.14m to 0.4m
0,26
TPB 45
02m to >2.45m
>225
6.4   4       Yr/wish Gm Graref/y Si!r/Cfy (R/ridw/ Sai/ f ( anp/r/e/y U M/herrJ Basaty
The yellowish grey silt/chy is generally found bcncaih the vertisols or reddish brown sill/chy.
It is interpreted tu be mainly part of the weathering profile of the underlying volcanic rucks and is a residual soil of completely weathered rock, usually of basa.il. 'fhe recovered samples are gencraJlv described as rtiffjfitoivuhgry/irrvirfi^n«r/A ci/yor JlLTflr jrZfy CLd>’. Ottw/rr jxr^Zjr
friMt Ji*f A> .wm, Nfwl/} of inf aft
The exploratory holes in which I lie yellowish grey clay/sill is encountcrrd are summarised in Table 6-4. ’ITie unit is generally not exposed *1 surface md the depth to the lop of the unit typically exceeds 1.5 m. The thickness of the unit is dot clear due to the depth of occurrence and difficulty excavating in hand dug pits, bur was found ro be more than 1.50m at TPB39- Onc might expect basalt bedrrjck to occur within 3 to 5m of die top of this unil-
Table 6-4; YeUow /Grey Clay/Silt exploratory hole locations
Exploratory Hek
Depth (mbgl)
Thiclcnei* (tn)
TPB 11
435m to >4.6m
-
2m to >2.62m
>0.25
TPB 12
>0.62
- -------------------------------
TPB 39
TPB 3B
1.4m tn >2m
>0.60
l.Sfii iu >3m
>l 50
TPB 47
0.2m to 0.6m
0.40
TPB 53
1.95m to >2 1 m
>0.15
Occasionally [his unit was found to be wet, probably because it is more permeable than the overlying clays wluch may confine groundwater
* - F4 ShLMC GeaiCTh Part 1(3)
71
14 May 1 IIfAr* DrwwnA- VjpMi vlijhtfu. XLvrtT) tfW j' trr C^Efnp
ElhrM X'tb            mJ Dnrt^f
6.4 J        Hi/ty h Comfdtlth WtJJbmd Basalt
Weathered Basalt w generally found dose to the surface in die north eastern par(
and west of the study area. It is generally described as: conrpletefy weathered basalt * <■^7 sib) sand) nbnamded to angular GR/1 PEL of basalt often with Mies and otxario^^^ The exploratory holes in which the weathered basalt is encountered arc sumnur
6-5. The maximum thickness that has been encountered is 4.5m (BH UBBSR02) Table 6-5: Weatbered Basah exploratory bole locations
Explorator)* Hole
Depth (mbgl)
Thickness (m)
BH UBBSR01
9.65m to 122m
2.55
BHUBBSR02
7.6m to Him
4.50
TPB 6
0.85m to >2 6m
>1.75
TPB 7
1.2m to >1.5m
>0.30
TPB 13
0.63m io >lm
>0.37
TPB 27
0 2m to >O.35m
>0.15
TPB 47
0.6m to >1.5m
>0.90
6.4.6 Cothtnum
The ( olluvium, described as •vbbh silty G'R/11 EL was encountered in TPB52 from 0
0.9m depth. This hole was located in the more undulating area in the eastern part of the s area The colluvium forms from a combination of relict alluvial fan materials and from th< creep of sod units moving under slope processes on sleeper slopes and become more mix
65          Structure
rhe geologic units in the Command Area are affected by several discontinuity structures. 1 ire faults / lineaments, joints and intense fracturing. The major trend of faulting / lineame futures discerned from satellite imsgenes ind on sue field observation / geomorphic evidi is along the NW - SE, NE - SW sod NNE - SSW Tins rs tn agreement wnh the general reponal structure Jotnts art frequently drpping st hrgh angles, from 60» to 90 Major streat and nvers ahgnments tn the sees may be governed by such map. drscontsnurtv structures. I’nldce the Rift area, such discontsmuty structure, art constdered not to be active
L’B H SRC4T Geotech Pan I (1}
72^^WJr
1
P^M* f -^
REGIONAL hydrogeology
Objective* offfydrojeofogfetl AvtMHBt
The hydmgcologjcil assessment in this report considers the regional hydrogeology and then
focuses on groundwater data obrained in ihe project ares (the proposed dam site and reserve xr
irca  lrrigauon command area and die surrounding area of the Beks River catchment). Illis
t
data is then used to assess hydrogeological issues of the proposed scheme.
The   objective   of   the   hydrogeological   assessment   is   to   identify   and   assess   those   issues
relevant
to the intended irrigation and drainage project, and in particular
•      geological and hydrogeological setting;
•      project area hydrogeology and aquifer characters□£*,
•       existing ground water users;
•      potential lor groundwater exploitation to support resettlement in the command irra. Thr feasibility stage assessment is based on available existing information, walkover surveys,
interview and dara gathering ar local VC'curda offices and villages, and data obtained during
geotechnical ground invesdgadons at the dam site and along the approximate route of the Main
rinal supplying flic command area- The assessment is supported by our experience and
understanding of the typical hydrogeological conditions to be expected, especially where there is
little existing hydrogeological dala available.
72 Review of Existing Hydrogco/ogieal Information
7.2.1 f :2,00V,000 jaiJr I fyi/rp^<ufap£a/ Map of liMtpw
This hydrogeological study has made use of data from rhe following two maps;
•       1:2,000,000 scale Hydrogeological Map of Ethiopia, (E1GS, 1988); and the
•       1:2,000,000 scale Geological Map of Ethiopia (1996).
Ihe 1:2,000,000 scale Hydrogeological Map of Ethiopia (EIGS, 1988) is a small scale map
covering the whole of Ethiopia and the detail is insufficient for the project area. However, the
map provides the regional stratigraphic and structural context, and includes inset maps of
topography and rainfall, water resource regions and recharge discharge conditions. The map
uses similar geological units and mapping is shown on the 1:2,000,000 scale Geological Map of
Ethiopia (1996) (ref 1} that is described in Section 2-2- Subsequent fieldwork and more recent
mapping have shown that some of the geological units for the protect area shown on this map
ire not accurate. However, no 1:250,000 scale published geological maps arc available for the
project area-
rhe Hydrogeological Map of Ethiopia shows a similar struemre to the Geological Map of
Ethiopia, but with a simplified geological stratigraphy. An aquifer classifies mm system is
applied, shown in Table 7-1.
Uh 1-4 SR04C
G cored* Purt 1 (1)
75
14-May-.J 1r f
Mr*'                jtytii&f 9t Efhttftj. Sitkjfry tf U ‘aftr iitrfp lilfvtfw A'dr                 f PnrMf Pamf
., T          and Productivity in Ab bay B«in (from BCEOM 1998
T,bk 2
— -----------------
------------------------ -
T
-
Extensive aquifers
Intergranular
permeability
Fracture permeability
Consolidated
sediment 5
Volcanics
rocks
"•-0^
Fr *t«t
•ntwgjt Perm^
O a 1 Alluvial deposits, sometime (eraced ?
vloderatehigh
0c r
.luvial and colluvial deposits
Moderate
91 1
^custnne deposits
Moderate
91 F
lis»ltk lava flows
Moderate
Tn 1
rarmabcr basalts
Moderate
Tv
Wclega basalts
Moderate
M a
Amba Alaii rhyolites
Moderate
T s
Amba Aiba basalts
Moderate
Tb
Ashangi basalts
Moderate
Tx
Undifferentiated volcan it es of the eastern border of the Ethiopia! plateau
High
T e
Blue Nile basalts
Moderate
K s
|Amba Aradam sandstones
High
J a
Anlalo limestone
High
Jk s
Tckcze sandstone
J E
Abbas beds
Low
J s
Adigrat sandstone
Moderate
d
Infra Adigrat clastics
Moderate
Y
Granite and quartzo-dioritc
Low
b
Un   differencial   cd   and   metamorph basement
1
Low
1 n
Low grade metamorphic
Low
h n
1 High grade metamorphic
Low
Th< itnugraphK units are almost the same as the geological map of Ethiopia  ,  The Upper Hclcs catchment area  and dam site area  are shewn to  compose rocks with "txftMH ^tnftrt tradun^Mt) f»^i. rtnh. buri,. ^htu)", classified as “:
(Oligocene to Muxene A,hang, basalts) poorly defined and decplv weathered basalts, covenng most of the catchment area;
Tv (Mb«. .o H™*** 
loose custKS tauli bounded between two N-S faults-
„ A „mihoom o( ,ufl, ,„d
Tn (Miocene to Pliocene Tarmabcx basalt C
.
,      ,l.      .
J  ^nxMimes porphynuc. often connected co
volcanic centres at higher elevation on catchment boundaries *I*bc rock units arc overlain in places by quaternary (Q  d
c    C5C_. .
deposits, with extensive aquifers with moderate inter granular n
scdimento)
cluX’’tl an<* coUuv*
^bikty (ttnron5oll
d.t d
C
The  southern  pan  of  the  command  area  is  shown  ai  a  low  productivity  rcglQru|   a   L   .  .
JcKalued aquifers with fracture and intergranular pcrmeabibty. pp^
a          lblc^”^^ eW>
1 H H SR(MC Genrcch Part 1 (1)
14 May-Hf/viW 
^ W^/r
N*
mctamorpluc rocks, granitic intrusives and dnlcntrs The stratigraphy in dus area is shown a* Precambrian undifferentiated metamorphic basement_
The map aJuo defines regions of major water resource. The Beks catchment and command area ate part of a region forming the highlands from north of Lake Tana lo the northwest edge of the Rift Valley described as.
"/ftgh/And J- iridejpfrad wid 
/«■ qujjrtrtxj vfjifffixr wtrtrrtM' / orgrwmfartfr. Goad
tfaritd  qualify  (JT>S  0-  1500ppm).  Mort  Jfrtajfrr  jtt  pffTHKiu/.  taUjprrxgJ  zrf  .ammart.  Dtfrfb  fa jirvNffda'j/rr u i9 - 100m. r.\ploilM m bir rr/trfarra.r, "
The mean annual recharge is estimated at 150 to 250 mm/yor.
7.2.2 slbbap Rww Hmwr MsuAv
fBCEOAf, 1998)
The geological findings of this study  are described tn Section 23.  This study  included an assessment of the ground water resources for Master Plan studies for whole Abbay  catchment, an area  of over the 204,000  km2 It included identification of basin wide hydraulic / hvdrogcological parameters as well as rrgionalised groundwater reservoir and resource assessments lhc study  included a  database of springs and wells and detailed hydrogeological assessments of parameters and information on wdl drawdown and capacity.
Regional Aquifers
The  distribution  of  the  lithological  lades  outcrops  over  ihc  Abbay  River  basin  can  be  listed  as follows (Source; Prr£w/#xrry IF u/rr                   Dfrth/mtfrfM&rtrr PAm farEMwpit^ WARGOS);
•       Igneous (mainly basalt] rocks: 56%, split between 4% for younger volcanics And 52 " p
for the older volcanics.
•      Afdimorphic basement fincluding Prc-Cambnan granites): 32%;
•      Sedimentary: 11%, and
•      Alluvium: 1%.
these  tigures   show  that  the  groundwater  resources   tn   tbe  Abbay   Basin   are  £0050}’  tn  fractured aquifers   consisting   of   volcanic   material   and   metamorphic   bascmenl   and   are   almost   entirely   in consolidated    rocks    basalts,    limestone    and    sandstone    and    metamorphic    base    mem    Thus    the water  flow  h  linked  Io  the  presence  of  fractures  and  the  retention  capacity  of  the  rocks  is  low. However,   it   is   anndpitcd   that   die   porosity   ol   some   geological   formations,   including   Mesozoic sandstones, mav have a sigmficani contribution to groundwater storage.
BCEOM have reviewed and interpreted the aquifer productivities associated with the
I iydmgcolugical Map of Ethiopia, see Table 7-3.
High productivity aquifers outcrop over a restricted surface within (he basin and where they do not outcrop, they are overlain by duck volcanic rocks. Most of the basin is covered with moderate productivity aquifer where ihe inoapared mean yield is about 5 l/s for 20 m drawdown. BCEOM summansr the hydrodynamic characteristic of various geological formations in Table 7-4,
bH HSR04C Graced] Parr 1(1}
75
14 Mar-11Ftdrr* Ofl9K7uft.     ifEttopt*. Mwiy tflTjfrr
Erhufiut Aii Imhifton jk.i' DrwKjp Pwrf
Table 7-2: Chs»«_of Yield and SpecificJiap^citv Values ( BCEOM )
1 iLtlt
Productivity of aquifers
Range, all
known
values
Specific capacity in l/t/m
Eatimatedophmum yield i|lJA
(20 m drawdown)
Range, 80%
middle values
Mean
Median
Range, 80%
middle values
Mean
Mcdi^ |
High
0.0340.5
0.27.6
33
2
1.8 68.4
29.7
16 |
Moderate
0.02 135
0.05-1.1
0.53
0.13
0.459.9
48
12*
.
Low
0 001-3.4
0006-34
0J
0.04_
0.05-4.5
0.9
zs?
Table 7-3: Estimated Permeabilities (tn/day) for Aquifer Productivity Chas (BCEOM)
—
Productivity of aquifers
Range, all known values
Mean
Median
High
0.16-124
14.5
------------------------- J 83
Moderate
014 62
2.1
0.41
law
0004 114
0.25
0.12
I* *52±Hvdrodvnamic PropenieiofGeological Formations (BCEOM)
b
Geological aeries
Discharge
in l/a
Specific diacbargc
in l/a/m
3x KP
f--------- n
Transmissivity 1 tn ml/s
QCf )L (Colluvium)
11
5xl(H
QCB2 (Basalt;
3.5
2x I04
3x IO4
TrB2 (Tertian basalt)
3.5
1 x 104
2x 104
QVCB. QCB1.TTB1,TU OB. TAAR, TAAB TASB, TJIV various basalts & volcanics
,
2
5 x IQ ’
TBNB I Blue Nile Basalts;
1 x 10s
5.5
J ADS (Adigrat sandstone
7 x 10-*
2 x 1CH
6
Metamorphic basemen’
2x 10’
*» x 104
I
4»10J
7x10  _j
s
BCEOM have also produced rcaervon mapping wth foUciwtng <^,^5.
•     Clas* 1 aquifers where poroaity sigmEkandy contributes to water storage;
•     Class 2: fissured aquifers where water resource is mnr.lv Imkcd to fractures, and
•      Class 3 granular or fissured rocks fornung very with essentially no water
] J1UltUH2JLMlsUi£tluUEi
ot K<ks
The BCEOM 'wdv states
springs and water tab e
that aquifer recharge is mostly linked to tainfall infiltration and th11 deluding met drimage, form one of the moat important
borehole abstnenon does not form a significant outpu'
output  of  the  aquifer  5y',Cn’flow   jnd   Qvet   drainage  An  otdei  ofmigmiudc  of  the  baseflow
when compared with spring 
discharge form sprmpj
cmetpence ts obtained through the Abbay nvet flow at the
whlfh » about MW m’/».
An assessment is made by BCEOM of long term groundwater rccha- Basin (since 1964). This identifies
' a^Ue» fat ihe
L’B F4 SR04T Geotcdi Pin 1 (1)
76, rather high values at the beginnmg of the conjidrred period. especially for years 1964 and 1965;
•       values equally distributed around the man during the period 1971-1980; and
•      values below or close to zero during the period 1983-1991
“yliiF. trend docs not seem to follow that of the vinous king term rainfall records and there is co definitive explanation, but BCEOM hypothesise dm this trend could be related to
de tore station which may have led to an increase in runoff and a decrease in infiltration- In lheir work, BCEOM propose the infiltration coeificems shown in Title ’-5,
Table 7-5: BCEOM Infiltration Coefficients
Geological Form anon
Infiltration
Coefficient
QCB2t QBC3 (Younger Quaremjuy Bauli)
20%
ClAC,JADSt KAA2,JANL.TRN"B, QCBl (Mesozoic sediments including sandstone,
nunc basdrs
10%
TAAB. THU. TTB2, TWOB (Older Ternary Basalt}
5%
Metamorphic basement, J ABB, KAA1, TJJV, TASB. TAAR. TOOL, TIRF. QVCB. QATB, alluvium (basement. some fine grained sediments, some Ternary ba sain &
volcanic*)
3%
3
The recharge expressed as an average continuous flow ranges between 250 and 300 m /*- It is naturally drained by the rivers as the storage capacity of the water bearing formations is knv in connection with Lheir lithological characteristics. At the end of The dry season, the Abbay over at ihr Sudan border still drains an average of 100 nrp/s I lowevcr in the valley escarpment or in the high land, the storage capacity of (he perched aquifers is generally not able lo ensurr a continuous flow to the springs
Mfrtt Quality
When considering the Ethiopian Standards maximum permissible levels, BCEOM report that. die typically exceeded parameters are; tier ammonia, pH. Colli dissolved solids, iron and manganese.
^irjnar- Review
I he hydrogeological investigation was conducted at regional basin level and hence is small scale. There is also little groundwater well and investigation data available. However, the work done by BCEOM in deriving infiltranon coefficients is appreciable and provides initial estimates.
Fnr estimates of groundwater potential, factors determining mfdnatw-a rate such as rainfall, typography, moisture content, vegetation cover, rock structure and other related factors are sire "Pacific Relatively few groundwater well data were considered to represent the geologic formations that have been used for the analysis aad evaluation of ground water potential.
S 'riL4f- r’«»crh I'on 1 fl)
T
14-May 11Vtdrrd 
of Erhttpia. Minitb) tfW'attr &Enrig)
Erhttfun Nrir Irntrtet -•»■» Dnatjgf Pnrttf
™ 
° f ,h' ’%M'7 rtud>,£T’T’ * «ta«d. Co..«tobk .(Ton ™ ™k to »H«e » much c>.Min   mfo™»o„ „
K
from a unde nnPc of sourcc5
A picture of the groundwater flow system is based on available geological mapping and subsurface information from groundwater extraction bores across the region. However the interpretation is hampered by the lack of any groundwater monitoring bores throughout the entire basin Also there are no tunc senes data to indicate aquifer response to recharge or groundwatcj extraction
Based on the data renew. the major aquifers in the 1 ana Basin comprise Ternary and Quaternary basaltic rocks The geological structure, including graben and half-graben structures, control the distribution of the major aquifers.
Groundwater flow in and around the Tana Basin comprises local and regional scale flow systems. The study shows that groundwater flows into the basin from highland areas tn the direction of Ijtke Tana, with groundwater discharge via springs, to streams and to low lying areas such as the Fogera Plain which becomes waterlogged during the wet season
The basin water balance study has shown that groundwater recharge results from surface infiltration. An infiltration rate of around 3- 5°o of rainfall is inferred from the rainfall-runoff relationships for parts of the rrgion In the Gilgel Abbav and die Gumera catchments it is considered that there is also groundwater inflow from up-gradient elevated areas around the major shield volcanoes at Mt Guna and Mt Choke
Ik contribution of groundwater to the overall Lake l ana water balance is considered to be minimal ‘Ibis is largely due to the presence of an 80 m thick clav layer covering the base of the Lake This low permeability layer limits vertical leakage to less than 10 mm per year.
Available aquilet data suggests that the yield from the fractured basaltic aquifers is relatively And it is therefore considered that (large scale) development of groundwater for irrigation in th ’ Tana Basin will be limited However more detailed analysis based on field dan would be necessary to provide definitive estimates of the n ailable resource and to establish groundwater management strategies.
The specific capacity (l/s per metre drawdown) tn the Lake Tana repon ha, been idenotied Irotn pumping data outlined in the Geolopcal Survey inventory for the Qualcrnan ^uva! aquifers, the Quaternary basalts, die Tarmaber Basalt and the Ashangi and Alba Basalts The
6
range, average and median specific capacity and yield of each of thro- r
' r,bl'   Sp“fc d'“ “ <». „r lht Kpo„
^quircr systems arc
L'B E4 SRMC C'.eotrch Part 1 (!)
78t'nirni' Of"*™™               <>/&**&* Miw/fn cfWattr <*• h>rrp
N'* 'tnfi D™**? l'^1
Figure 7-1: Specific Capacity (l/s/m) of aquifers in the Tana - Bclcs region
Legend
•    0000 0130
•  0 134 0 330 o  □ 377 0S00
•   0 633 - 1 000
40        20         0
40 Km
O
6 429
• 4.SIUH(, Gmicch l*an 1 '!)
79
l*lMay 11Ecdr*' DtinrM RtpM; of Estop* Sbastn oflTafrr & Entrg
EttoftM N/> IrripfW! rf*/ Prw»<r Profit
-6: Yield and s
ity values of major aquifers
Specific Capacity (1/a/metre)
Pumping rate (1/,
Aquifer
Range
Mean
Median
Range
Mean
Quaternary
.Uluvials
0.02 O S J
028
033
1.3 -6.5
4.14
Quaternary
Basalts
0 034 - 6 43
0.65
0.11
1 ->10
3.85
Tirmabcr
Basalt
0018-3.31
025
0.14
0.7—16.R
3.63
Ashangi and
.Alba Basalts
0.008 1.49
0.27
0.11
0.6” 17
4.20
The   report   recommends   further   hydrogeological   investigations   to   improve   the   evaluation   of   the groundwater resource in die Tana Basin.
7.2.4 R«7cu* of existing wafer jvpph schemes and Uyorrda I villager comments
A baef review has been made of some of the existing local water supply schemes in the catchment and surrounding areas and the following conclusions drawn:
•      At certain sites it was found that a borehole was drilled |ust a few’ meters upstream ofi spring, where a cheaper option would be to protect /cap the spring Such drilled wells intercept the spnng flow resulting in its decrease This was confirmed during field visits from local brneficianes / villagers at the respective sites.
•      Deforestation results in diminishing and disappearance of spnngs that w'err found previously in abundance (source local people) This is due to the reduced infiltration / increased runoff that occurs with reduced vegetation cover
•      Documents and data regarding previous work done in the project area were not available in the respective region water resource Bureau, zone and VCorrda offices We were informed that documents and data were “lost” when concerned responsible staff were given a new posting and took the data with them
•      Related to the problem of "lost” data is the absence of formal / proper data handling systems. Data arc kept by the concerned individual experts and rather than in any suitable database system which “stays” with rhe office rather than with the individual. There is a nerd to develop a data handling system for water supply data.
7.3 Summary
The major aquifers in the I ana Belrs Basin are likely to Comprise Ternary and Quaternary basaltic rocks with moderate fracture permeability. The distribution of the major aquifers is controlled by ihe geological structure, including faults and potentially graben and half graben structures, as well as the variable contact between basement and volcanic rocks, the presence c»r absence of Mesozoic sediments in between, and the generally steep topography, llic regional hydrogeology is therefore complex and require prorevt specific investigation
The available aquifer diLa suggest thai the yield from the fractured basaltic aquifers is relatively low to moderate and it is therefore cnstdered that the potential for Urge scale groundwater development (for irrigation) will be limited.
L’H F4 SR04C, Growth Pah I (1)
8<l
1
14 May 1D*****' Rfd*'
r fh'cf^ ** trn^ DwtiSt
Stwfr, ^fir^rr & E^
8
8J
8.2
82.1
82.2
project area groundwater data
introduction
'Illis Chapter describes the groundwater data collected and observed in the project area.
Fieldwork observations at the Command Area were mostly made between November 2009 to
February 2010, during the dry season and in the Dam Sire Area between May and November
2010. at the end of the dry season and during the wet season. It is important to note that
groundwater conditions will vary* seasonally and these data should be considered to be
indicative
D>m Site and Reservoir Area Groundwater Observations
Surf act Obsen^atiom
Baseflow conditions tn the L'pper Bries can be assumed to occur at the end of the dry season,
in April and May. At the dam site very low flow baseflow was observed in the Bries nver and tributaries upstream of the dam site during reconnaissance visits in Apnl 2010 (sec Section 9.5).
This suggests that groundwater supply to Bdcs river is not significant.
No  springs  were  found  in  the  reservoir  area  during  reconnaissance  work,  but  two  springs  were found in the following locations near the dam site:
•      About I km downstream of the dam in a guilty
•      Near to the eastern potential Quarry site (Quarry site I), at relatively high elevation.
Due to the interlayered nature of basalt and tuff in the area, it is possible that the springs emerge at the contact between overlying more permeable basalt ind underlying less permeable ruff, but this was not dear from the limited exposure
GrvMftd Imvstigation Obitrvattons ami Momtonnt^
No ground water was encountered in trial pits at flic dam site, and no waler strikes were recorded in the dam site boreholes, but it should be noted that during rotary coring water flush was used and therefore minor strikes would not have been detected, and that trial pits were excavated at the end of the dry season
At the dam site, piezometers were installed in four boreholes (UBD01. 02, 06 and 07). The monitoring results are shown in Table 8-1 and a summary is provided in Table 8-2.
The piezometers were measured during the drilling investigation penod but as thev were all installed on the left side of the nver, monitoring was only possible when works were underway on the left side (up io about 27* August 2010) due to access restrictions crossing rhe river. The monitoring period was therefore in the middle part of the wet season; groundwater levels are expected to be higher at the end of the wet season.
The results tentatively suggest chat the groundwater level is about 12m below ground level on the left abutment, but that it may be confined within higher permeability’ basalt units. Jn the centre of the valley, alluvial deposits appear to be in hydraulic connection with the Belts River waler level
1 < SR04<; Gcotcch Pan I (1)
81
14-May-l 1Frimt!            RfM. tfEMfw. Mtatfj rfW'dftr L:bff>tJi <\u Imgrfnn <r*d Drunjp Prytif
zomciric                                     _ GW Level, m
data at dam site borehole*
Table 8-L K«
Date
GWLe
vel»m
Momiog
Evening
Morning
Evening
RHDBD01
BH UBD 07
138
1194
3 Aug-J0
42
------------
1163
12.41
4-Aug; 10
5.3
161
5 Aug-10
14 1
14.15
5-Aug-10
5.72
_ _______ 3J
13.75
13.78
6-Aug-lO
12.6
1235
7  Au  JO
.      g
13.8
1393
7 Aug io
12 6
12.56
139
12.6
8 Aug 10
12 14
1223
9 Auk 10
12.94
133
10-Aug-10
ai
13.45
11-Aug-10
134
134
12 Aug W
13.35
1336
B Auk-10
13 37
13.37
14-Aug 10
13.38
13 38
_____________
IS Aug-10
1337
1336
16 ■ Aug  10
_ 17-Aug-10
13.5
12.95
12.8
12.7
l^Aug 10
13.5
1394
_
19-Aug 10
13.5
13.45
20 Aug 10
13.8
13.85
21 -Aug 10
139
13.95
22 Aug 10
13.97
14.2
25-Aug 10
13.9
1335
24 Aug 10
12.8
12.7
25-Aug 10
1194
1198
26-Aug 10
12.9’
12.9
27 Aug W
1198
12.93
BHUBD02
____________________________
BH UBD 06
13 M 10
1.79
1.76
13Jd 10
2,71
14-ld 10
1.75
1.74
14-ld-lO
171
168
lS-ld-10
1.71
1.73
15-ld-10
146
2.4£
16 JdlO
173
1.73
16 Id 10
2.42
14
17-lul-lO
1.73
1.73
17-Jd-IO
238
18-Jul 10
1.73
1.73
18-Id 10
2.4
2.39
I9|u! 10
1.73
1.73
19-|d 10
244
2.43
20-lul-W
1.73
1.73
20 Id-10
141
2.4
2l-Jd-10
1.73
1.73
21 Jd 10
2.41
141
22-JuMO
1.71
22-lui-IO
135
UB F4 SR04C Gcotcch Pin 1 (I)
82
14-XUy I'Eib^ff
of E/inpf a, Mim/tr/ ofUatr? r-
Dr **1P PW*
GW Level, m
Date
GW Level, m
Morning
Evening
Date
Morning
Evening
23 |uJ 10
1.65
1.64
23-Jd-10
228
2.23
24 |ul 10
173
1.73
24-Jul-IO
2 18
22
25-Jd 10
1.73
1.65
25-Jd 10
222
2.25
26-Jul 10
1.69
1.6
26 Id 10
2.27
226
27 Jd 10
1.7
1.65
27 Jul 10
245
2.48
28-Jd-lO
1.7
1.65
28 Jul-10
2.65
263
29 Id 10
1.69
1.62
29 Id 10
267
28
30 |u) 10
1.7
1.68
30-Jd-lO
292
288
31 lul 10
1.72
1.66
31-Jd 10
2.82
2.8
1 Aug 10
1.69
1.67
1 Aug 10
2.68
3.13
2 Aug 10
1.7
1.78
2 Aug-10
2.89
3.7
3 Aug 10
1.69
1.68
3 Aug-10
256
261
4 Aug 10
1.55
1.62
4-Aug 10
245
235
5 Aug 10
1 65
1.61
5-Aug 10
246
231
6-Aug-10
1 58
1.57
6 Aug-10
2.47
247
7-Aug-10
1.5
1 49
7-Aug-10
25
2.48
8-Aug-10
1.56
137
8-Aug 10
25
251
9-Aug-10
1.53
1.52
9-Aug 10
247
255
10 Aug 10
1.55
153
10-Aug 10
255
23
11 Aug-10
1 55
1.57
11 Aug 10
245
253
12-Aug 10
1.54
1.56
12 Aug-10
25
23
13-Aug 10
1 56
1 52
13-Aug 10
25
255
14-Aug 10
1 51
1.51
14 Aug 10
251
231
15 Aug-10
1 51
1.5
15-Aug 10
253
252
16-Aug-10
1.52
1.54
16-Aug 10
2.5
2.54
__17-Aug -1(1
1.53
1 56
17 Aug 10
251
232
18-Aug-10
1.55
1.58
18-Aug 10
251
234
19 Aug-10
1.57
1 58
19 Aug 10
252
253
20 -Aug-10
1.57
1-56
20-Aug 10
254
254
21 Aug 10
1.55
1.56
21 Aug 10
253
255
22-Aug 10
156
1.57
22-Aug 10
253
255
23rAug-10
1 57
1.58
23-Aug-10
23
233
24-Aug-10
1.58
1.54
24-Aug 10
2 2
22
_25-Aug-io
1.55
1.51
25-Aug-10
23
1.96
26 Aug 10
1.47
13
26-Aug 10
26
24
27-Aur-IO
1.51
1 54
23
2.4
1 * SRou Gccxcch Part I '1)
83
14 NUv-11EtfapiifWt JmptM a* Dnauff Pr»trf
Table 8-2: Groundwaler Piezometer Details in the Dam Site Area
Borehole
Location
Piezometer
Depth
(mbgl)
Strata
Typical W,,wUvtj
^P'h Duriaj
Monitoring Pf^
(mbgl)
UBDOI
Dam lxis left abutment mid-
slope
38.70
Basalt
12.6-142
UBD02
Dam a us centre of valley
adjacent to river
50.00
Tuff (note granular
alluvium above,
possible leakage or
connection)
1.5-1.R
CBD06
Downstream dam body
centre of valley
10.00
(»anular Alluvium
22-2.9
UBDO7
Spillway
35.00
Basalt
2.6- Vthcn
12.1 - 12.6 (spurious readings?)
It was not possible to monitor water levels al the nght abutment, bur onr might expect (here to be groundwater in the thick sequence of sands and gravel* that has been found at BHI1BD04 and I 131X15. as well as in the underlying basalt.
At detailed design stage additional piezometer installation and groundwater monitoring is recommended
8.23 Ptrmtabilih
Two types of permeability testing were completed tn boreholes at the dam site area
•      falling bead permeability tests tn soil strata.
•      Lugeon (packer) injection testing rock strata m 5m lengths
The results of these tests are discussed tn Chapter II
8 2.4 Grvundwalfr IFr/Zr
There arc no permanent settlements in the dam site area and therefore it is not surpnstng that no wells were found tn the immediate vicinity of die dam site, or low er reaches of the reservoir
area
H SR(MC (leocech Pan I (I)
84
14 Ma/'l1j^Df***™ ty**;
& Ettfr&
rw
^r< N* I”**'             Dn”** Pf^f
Two boreholes were completed to 13m and 15m depth in the Command Area, near bendika / Jiui. The boreholes penetrated thick sequences of red silty clay with bedrock below about 12m
(tuff and basalt respectively). Both boreholes were dry during drilling, with no groundwater observed.
Groundwater was encountered in fourteen of the 42 tnal pits (i.c. 33%) tn the Command Area, summarised in ’fable 8-3. All other trial pits and boreholes were dry It should be noted that trial pitting was completed in the dry season
Table 8-3: Groundwater encountered in the exploratory holes
Depth groundwater encountered
Exploratory Hole
Geological Unit
(mhgl)
TPB 6
Water stake ar 2.25m
Weathered basalt
TPB 11
| Water strike at 4 55m
Yellow grev uh / dav (weathered basalt)
TPB 20
1  Wet below 1 m
Vertisol
TPB 22
Standing water at 23m depth
Vertisol
TPB 28
Moist below 0.5m
Vertisol
TPB 29
.Moist towards bottom (2.5 to 3mj
Vertisol
TPB 30
Moist below 2m
Red brown siltv dav
TPB 32
Wet below 1 4m
Red brown sdjy day
TPB 34
Moist below 2.5m
Red brown silty day
TPB 35
.Moist
Vertisol
TPB 40
Dry-, clay 3.6 to 4m noted as wet
Red brown siltv day
TPB 45
U’ct below 2m
Red brown siltv clay
TPB 46
U et below 2 4m
Vertisol
TPB 53
Wet below 0.9m
Vertisol / Yellow grey silt / clay
I3ie intermittent presence of groundwater, typically at below 2.5m depth, suggests that there is moisture retained within the clay units but that dus is localised, probably related to run infiltration and not part of a widespread aquifer
Command Area Weil Point Inventory
A water point survey was conducted in the command area. Data for 21 surveyed groundwater wells including location, elevation, well depth, aquifer material and type of well are tabulated in I able 8-4 Die locations of the surveyed wells are shown on Drawing L’B/FS/GEO/100/03.
All the water supply wells visited and inventoried arc without official recorded well data. Data regarding the history of the well are also not available in the respective region water resource Buicau, Zone or Woreda water desk offices. The only available records were well log data for four shallow wells drilled and installed with hand pump in one of the settlements (Annex O). Consequently, certain data for the well inventory was gathered orally from rhe respective well ^mcficianes,
bRCHC
Part I (1)
85
14-May 11FfM DaMCMttt fyMc tfEtfapi Mtmfrv ITdtrr ^EtffX, EthqtM Nut Imgirttt wi Dranjft Pryta
^X<’i
"■"rf“mpkn"'d”of ”■*“■ hhon'“’
HB02,   NH4,   H2S,   C02,   TDS,   Total   Hardness   and   PH.   Water   quality   Test   results   arc   pv^   lQ Annex N and discussed in Section 9.7,
There are large numbers of hand-dug wells m the command area and a few drilled wells Shallow band dug wells are typically 8 - 20 m deep, while drilled boreholes are 30 - 110 m deep
Collected well data and information from respondents indicate that the groundwater level fluctuates according to season, and is shallower in lower King locations and along streams and liven. Typical depths to groundwater vary from just 2-3 m to over 20 m Only a small proportion of the wells were visited, but these all appeal to be excavated into weathered basalt The groundwater source rock at the well sites is mainly inferred from discussion and from the surrounding geology and is not confirmed
During the well point survey. no springs were encountered However, social survey work (below'! indicates that springs form part of the community potable water supply source
»»
1 F4 SRfMC Grnacch Par 1
14          11
it-f&tn/1
\
Nt If Ifffj^fr»t> Offrf Drvrn^r
Sturt/fn »f Water littery
Table 8-4: Data inventory for surveyed groundwater wells
1  Well
I ID
Location
UTM
Easting | Northing
Alt
masl
SWL
mbgl
Depth
(m)
Q
(l/»)
Aquifer
materia)
Drilled
date
Owner
A
Ute
......
1 UBI
201445
1245154
1,179
32
J
Weathered basalt
2006
Pawi village 46 domcsuc water supply
Drilled well. On spot installed with hand pump Afrtcdcv  type. PH 6.2, Temp 27’C, CONDUCTIVITY 150
UB2
200622
1248547
1,197
1
Decomposed bault
2007         j
12
Primary school water
supply
Dug  well.  On  spot  installed  with hand pump Afriedcv type
UBS
200244
1248690
1,185
13
Decomposed basalt
2008 (
1
Village Heles number 2 water supply
Dug well, open
LB4
198531
1250057
1,201
81
2.5
Fractured 8c weathered basalt
1999
Mambuk town water
supply
Drilled  well  Motorized  with  piped dntnbutian system.
CDM -NGO funded
UBS
198607
1249738
1.195
87
1.5
Fractured 8c weathered basalt
2008
Mamhuk town water
supply
Drilled well. Motorized with piped distribution system. CDM NGO
funded
| UB6
1
209539
1246859
1.067
14
36
Weathered & fractured basalt
______ 1      2(8)3
Pnwi village 4 water
supply
Drilled well < )n spot installed with hand pump
' UB7
210179
1246896
1.059
10
15
Weathered decomposed basalt
2010
Pawn village 4 water
1 supply
Dug well On spot installed with
hand pump
j UB8
212255
1250461
1.065
36
Weathered & fractured basalt
2(8)3
Pawi village 5 water
suppl V
Drilled well tnstalkd with hand
pump
UB9
216434
1252497
1.099
no
2.7
Weathered A fractured basalt
2008
Catholic church water
supplv
Drilled well. Motorized pump with distribution svstem.
UB10
217251
1252899
1.100
9
17
1
1
Decomposed basalt
1
2010
Pawl town village walrr I supply
Dug well on spot installed with hand
| pump.
IJH Fl SR04C Gcotcch Pact 1 (1)
87
14 May 11I'./http*
'                 Location
‘
up*
Remarks
Easting
UBH 217781
222.064
223318
Northing
1251308
}
I 1249973
1.132
1.148
1.112
1.103
1.067
Aquifer
material
Weathered Ac
fractured basalt
Drilled
date
2004
UB12
—
UB13
UB14
UH 15
t HI6
Weathered basalt                            2004
■
I
1252567
217246 1252534 214846 1246460 2m?3 1259504
1287 190
1287J-5
Weathrrrd    Ac
fractured basalt
Frar rured Ac
weathered basalt
Fractured and
weathered basalt
Decomposed basalt
2007
2 OCX,
2005
2009
Owner
&
U.e
Pawl village 30 'water
supply for a Clinic
Pam village 9 water
supply for a Clinic
Pawi   village   10   water
supply
Pawi agriculture research centre water supply__________
1 Tana Bclcs girls lioarding
I school water supply___________
Dolled   well   on   ipot   installed   with
hand pump_________________________ .
Drilled   well   on   spot   installed   with
hand pmiip__________________________
1 Drilled well on spot installed with
hand p .n.p
Drilled well motorized with
distribution v. ~tcni
Drilled well mot on zed with
i distribution system.
Fractured Ac                                    2005 weathered basalt
1.221
Fractured and
weathered basalt
2005
\ dlage water supply
source
Jam Send wuha village
Jam Send Wuha village
Dug well ins tailed with hand pump
I)ruled well ( >n spot installed with
hand tii;
Drilled well On spot installed with
__________________j hand uurni’
1287545                U25
I Drilled   wdl.   (>n   spot   installed   with
I
243192           1287525                1.22”
hand pump
Drilled well ( >n spot installed with
hand pump
UB21               198636
1  1250263
Frat lured Ar                            2005              Jam Send Wuha
weathered basalt
' Fractured & 2005 Jawi Send Wuha
weathered basalt
Fractured Ac
Weathered basalt. fatwM* ♦' H/Mpw. .V/w/rn 0/ irjftr & E ^'ii W**W P™”*' '>A'
^rn/n^t/Amr Potable Water Supply Survey*
Jn addition  °  ^
rr
c wcH'P°,r,l inventor)’ described above, data on water supplies has been
collected 315 P‘,rl ^IC ^8*°* Socio-Economic Surveys element of the Upper Beles project
iTiis b reported in the Supplementin' Report SR03A Resource Users and Socio-Economic $. luctmcts from this report arc provided below.
PelabkW'UlerS^
Based on data provided by the VCorcda offices, the mam sources of potable water in the 37 kebeles situated fully or partially in the project area arc presented tn Table 8 5. In all 37 kcbclcs manv households fetch water from nearby streams. Households in 2" kcbclcs use one or more unprotected springs for potable water
In 20 kcbclcs households fetch water from hand-dub open wells, and some households in 24 kebeles use protected springs Wells with hand pumps arc found in 29 kcbclcs and deep lubrwcllfs) supply potable water to households in 7 kcbclcs
Table 8-5: Main sources of potable wafer in project area kebeles
SDA
r
Nr of
kebeles*
Stream
Unprotected
spring
—
Protected
spring
Open well
Well with
hand
pumps
Deep
lubewclh
I
9
9 kebeles
7 kcl>ele*
9 kebelcs
2 kebeles
8 kebelcs
2 kebeles
8
8 kebeles
2 kcbclcs
3 kebeles
3 kebeles
7 kebelcs
1 kcbelc
iv&v
22
22 kcbclcs
18 kcbclcs
12 kebeles
15 kebelcs
14 kebeles
4 kebelcs
Totals
39
39
27
24
20
29
1*1
7
100%
69%
61%
51%
74%
18%
Sauter: XVorcda office* A: focus group discussion*
•Nch< \nka*hi Hurpi Kcbck (Dangur Wcnda) w situated pirttaJh in Stage arrj I and tn Stage area III. and Ihstncr 2 Village 17 Kcbdc (J’awc Wctcda t< situated parnalh m Stage area I and tn Stage area IV.
4he main sources of potable water for the surveyed households in rhe 16 surveyed kebeles are shown in Table 8-6
Table 8-6:
Nr of
surveyed
kcbclcs*
Stream/
pond
Unprotected
spring
Protected
•pring
Open well
Well with
bund
pumps
PWS
acbeme
4 to 30%
4% and 5%
(2 kebeles
7 to 48% (3 krbdesj
26 to 78%
(3 kebeles)
7 to 60%
-
[
5 to 30% i3 kcbclcs'
5 to 15% (3 kcbclcs)
5 to 65* •
0%
35 to 65%
25%
(1 kcbdc)
5 to 65%
10 to 45%
5 co 60%
5 to 70%
111 to 65%
5 and 40%
'8 kebeles
(6 kc beles)
(4 kebelcs ’
(5 kebeles
(7 kebeles)
P kcbclcs;
47. - 647.
4% - 45%
5% - 65% |
0% - 78%
7% - 65%
0%^40%
C
>Urn" behold turvevs
”’  V \nka>h.i Hnrgi Kcbdc is parrially Mtuatcd m stage area I and III a local of 16 kcbclcs have been surveyed
•totrch Pan
80
14 May 11FnMfArwfcntf1. RrtM-ef E.'frrtfw. Mitt! fry f U Jfr C^Eiffp
Efhttfm Nt Jr                Dnawgt Promt
In 15 of the 16 surveyed kebelcs, 4° o to 64% of the surveyed households f
|
ctc 1
from a local stream, and 4% to 45° c of the suneved households m I1 L«k i
springs.
KCDelcs use u
nnrr
w
A|f>
P^’ecu,
Semi-protected open well
Concerning protected /improved sources of potable water, 5% to 70% of rhe surveyed
hou cholds in 8 kebelrs use open wrlls In three kebelcs water from a PWS scheme is used by
to 40® o of the sun eyed households; 5% to 65* o of the households in 11 kebelcs fetch wile
from a protected spnng, and 7% to 65% of the households tn 15 kebelcs have access to wells
with a hand pump
The wells with a hand pump were usualh installed by government agencies (i.C- ARD Woreth
office) or a NGO. The well, and liand pump arc managed cither by the ARD Wired* office or
the Kcbele Council. In at least seven surveyed kebelcs, households pay ETB I to ETB 13 P*1
month respectively in water charges
According  to  the participants of the thematic focus group meetings tn the 16  surveyed •‘ebclr’- the quality  of fetched water is not good in five of the 16  surveyed kebelcs. Pollution by  aiumd* u given as the main reason foi poor water quality.
Hie (female) member, of the surveyed households fetch water two to three tunes per day- 1* average distance to waler sources range, from only 20 m in one surveyed kcbele in Stage area 1 to 1.3 km in one surveyed kcbele in Stage area IV
The reported depths to the ground
•      Stage area I:
•       Stage area III;
•      Stagr area IV and V:
water vaiy m 16
5 Io 18 metres
5 to 40 metres
8 to 20 metres
surveyed kebelcs arc as follow s:
CH J'4 SKCMC Grotcch Part I (!)
14-May-J1)■ in,
XV* W“,w Cl'u"'*'
According to the participants of the thematic focus group meetings there are seasonal water shortage for 3 to 5 months each year in at least 5 of the 16 surveyed kebclcs
Lining for fetching water (left) and carrying water home (right) in D. 1 Village 49 Kcbclc
g.5.2        Potabk Water Supfib Provided under the Tana Beiej Prv/ert
Under the Tina Bcles project (1985 to early 199(H) buried pipe water supply systems were installed supplying water to above ground cylindrical header / reservoir tanks in each village (in Pawi Wbicda). There were two main sources of water:
•      A small dam at +1,243 m elevation on die Oilgel (I.ittic) Bries river, and
•      A small writ on die Chan river (stream), a tributary of the Bula river which joins the Enat (main) Bries near Pawi
PWS scheme with fibreglass water reservoir in D.l Village 4 Kebclc (left) and well with hand pump in D.l Village 49 Kcbclc (right)
Slow filter and chlorination treatment works were constructed downstream of water source I he pipes for the putable water supply pipelines, as well as for the storage tanks, were of glass fibre reinforced polyester resin and were prtxluced at an on-silc pipe factory established in
1987.
13
le Wa,cr 5Upph* systems were to ensure year round supply ro the settlement kebdes in Pawi Woreda, i.e. over much of stage development area 111 on the right bank of the Enat (main) Belts, as well as over much of stage areas JV-C and V,
L ’B HsH(mc;
Pentech Pan i
0)
91
14-May-llFtiml D'^t. 
un
f ■
c™*  «  »  understood  fa  fa  poubk  ««  «W*  ««»  «'>'8*  rkforo  fc,
K « „ W r^tato tee .PP«n* to
T'"'"’
wl “ ” bl,K“ "* S'Jm“'
’"“P*™- Sr™, <,f 4 ’
g 6 Population and Potable Waler Demand
T»bk 8 - summines the present 2010 population for the protect area of 137.626 ha and
the protected population to 2020 and 2030 by SDA‘. The current population is estimated at 101,724 HHs, composing 80,772 rural I Ills and 20,952 urban I IHs living in the W’orcda l0Mtl principally Fendika, WeikMeda and Paw The average number of persons per HH is 4 39 pving a current population of 446,570 persons (354,590 rural and 91.980 urban).
Tabic 8-7; Population Projection (or the Project Area
“nr
2010 |
2020
2030
Rural
Urban 1
Rural l
Urban
Rural
Urban
n
u1
5.929
6.835 I
15.537
11,140
13,500
16,831
IB-E
3.6F
69 |
-
IB 33
3.770 |
229 J
-
IBS
1.083 |
-
in
7.722 |
3.487 1
7.894
5,446
6.944
8.227
IVA
<891 1
5.902
6/80
IVBE(N)
3.297
ejr
449
7,575
678
IVW
4.782
575
-
1VBE 5)
1.709
2,062
2369
TVC-N
16,3^
982
1        22,125
1.983
24.642
2.997
IVC-E
5,814
1,058
6,584
1,653
6,918
2,497
IVCS
7.473
4,776
7,068
7,459
5,208
11.269
VN
\834
I loot
[         8.79
1           2.509
9.126
3.790
V-W
250
3              50
!  1        2,8V
’88
2.925
1.191
vs
3.97
3              82
5  1         4,4&
1.295
4,614
1,95'
[Total
80,77
2          20,95
2 |        89%
8|        32,722
90,603
49,438
Sount ( vnaukraa cmtrulri SwJ «t CSA n,^
The urban popuhtion B expected to grow from 21% nf ~
T7./v. on-wi .»i-o l
27% bv 2020 and 35% by 2030, while the nrr<^. i , 
t               MlO 10
P rnJ«c jura populate>n in 2OK'n
rr
I -
___ „ P
population gmux bv 11% to 2020, md
only by 12% from present to 2030 Tim t exnccied « »k u , 
wa
P* a ai the driver of urbanisation is ven' srront,
mi
rven in woreda towns ind die increase tn the                »
oppor_ _ v       runihc-s in urban irei*. 
Potion I, hotbed bvarouw
* fl"
* Refer SR 02B. Impird Agriculture A \fri> cCtOumic Dcvelupmisit Rcpun
LB 1-4SRMC Gcmcdi Part 1 (1)f Pt****'
•fFthnpt. Miaufry *tr &E*fp
The PUS water demand projection is given below based on 15 l/capita per day for rural households and 25 l/capita per day for urban households With unproved water supply systems these may be on the low side.
'ITic current and projected household potable water demands are about 2.8 Mm /year and 4.16 Mm'/vear respectively, see Table 8-8. Relative to the annual demand for irrigation for the irrigation project of about I.20*  Mm- /vear’ this is negligible
5
7
T«ble f k8: Potable water supply demand projections for project area
2020
Nr
Description
Unit
2010
Rural Urban
Rural
Urban
2030
Rural Urban
1
2
~3
4
5
6
Population
Per capital water requirements
Total water
requirements
HH
Persons
1'person f
day
m’/d
Mm’/year
rrP/s
80.772 354,580
15
5319
1.94
0.06 |
20.952
91,9-9
25
2,299
084
2.78
003
009
89,986
395,039
15
5.926
2.16
0.07
32,722
143.650
25
3,591
1.31
3.47
0.04
0.11
90,603 397.747
15
5.966
2.18
0.071
49.438 217,033
25
5,426
1.98
4.16
0.06
0.13
8.7
Future PWS ProgrAmmes
Based on discussions with the respective water resource office staffs, no major water supply projects are currently planned in the project area. Vinous on going developments arc limited, for example to mobilize targeted beneficiaries to excavate dug wells to meet domestic water requirements.
DrvtMpfitmt supplementary report
^SRtHCGnjrech Pift j pj
93
14-May-l Iof Ethiopia. Mi turn ofVAtr    l.nap
9
9.1
J JD'a"Jf,pnfta
j .l ^^'^ '
project area hydrogeological assessment
9JJ
Hydrof^^gic^! Units
‘[he proposal dam site, reservoir and irrigation command area is characterised by different hydrogeological units rhese arc river deposits; alluvium; colluvial / residual reworked deposits, basalt, tuff, dolente and the basement rock units. A summary map of the hvdrogcology of die Command Area is provided as Drawing UB/FS/GEO/1(X)/03, and shown at reduced scale on figure 9-1
9                       Rntr dtpodts / jramdar alhtvium
The over deposits are found along the Main (F.nat) Belcs river and its major tributaries bed and banks and in the adjacent alluvial plains. Ir is mainlv unconsolidated cobblv-sandv gravel with subordinate silry-day-soils. The duckness of the deposit is vanable but at boreholes in the dam site area has been found to lie more than 10m deep.
This material being coarse and unconsolidated to loosely consolidated has potential for infiltration and to be waler bearing with relatively high permeability, estimated to be greater than lO’m/s
g/J Vtrtisttl / cohtstvt alluvium
Alluvium is found covering the relative topographic lows and plain lands. It is dark to dark grey consisting dominantly of silty-clay co clay soil of very high plasticity. The thickness of rhe deposit as inferred from trial pit excavations and stream cuts is generally less than 10 m, and often less than 1 m
The alluvium being dominantly silty-clay to clay soil tends to have low hydraulic conductivity. Based on the hydraulic conductivity tests (using inverse - auger hole method, .Annex M), the
6
average permeability is about 3.6 x 10   m/s. According to USBR soils with a coefficient of
6
permeability between 10 • m/s to 10"  m/s arc considered to be semi pervious
lhe loosely consolidated soil materials consisting of gravely and sandy soil material arc of moderate hydraulic conductivity that can act as potential recharge sire and water bearing layers. I lowcver, the material consisting of stiff to very stiff sihy-dav to clay sod material has poor mfiltration characteristics and can enhance runoff. The material can act as confining layers to
underlying aquifer material
95
14 .May IIMrtil
R/fM' if k/hufu, Mniifri if W Wrr cw E«<*£
h/iwpwfl Nur J/njutot aid Dniugt Pwtf
Based on the hydraulic conductivity tests (using inverse - auger hole method c0 j
silty day soil material the average permeability coefficient determined was 10 s nun/ 41 m/s 'ITus material is therefore considered as semi-pervious.
9.1.5 Burt
The lock is found exposed ovet significant pans of the project area. Il is commonly w |]
c
fractured and slight to highly weathered. Occasionally it is slightly weathered with medium Io widely spaced joints The joints and fractures arc partly open without secondary infill raa(eiaJ
I lowevcr some of the basalt is amygdalmdal tn which pores are filled by silica quartz. The jointed / fractured basalt and vesicular basalt tn which the vesicles are open without second^ infill material would facilitate recharge. However, the rocks with joints and porous spaces filj by secondary infill material, and the massive amygdaloidal basalts, retard infiltration
llw fractured porous and weathered rock units form water bearing layers. The open and interconnected porous spaces and discontinuity planes that arc without secondary infill mitou] can be considered as potential infiltration paths Contrary to this, die massive and slightly fractured units bong of low hydraulic conductivity can be considered as non - water lieanng
layers.
91.6 Tuff
I’he rock is found exposed tn the dam site and reservoir area and my underlie parts of the Command Area. It is commonly lithic, massive to widely space and at places closely spaced jointed and slight to highly weathered.
<0
1 uff naturally is scnu*prrvious tn impervious. Hits is due to the texture and composition of die material The in hie rock fragments are well cemented and indurated so that recharge is hindered The material upon weathering and dccompoutxm is commonly changed to eJay soil material that is cohesive and of poor hydraulic conductivity. Consequently, such a material can be considered to form a low recharging and poor potential aquifer/water bearing material in the area II can an as a confining layer to an underlying iquifer material
9,1.7 Doknfe
DoJemc outcrops are found exposed along the ever bed and banks It is commonly maSMVC and slightly weathered Consequently. the rock unit can be considered as semi-pervious to impetus hindering recharge Accordingly, such rock units can be considered as insignificant aquifer materia) and an aquiclude in the area.
9.1.X                      Ruffe
The  b«cmcn.  rock  umts  arc  found  exposed  rowuds  the  uj  of  .he  Mun  canal  ahpunen.s  m Command Area. The basemen, rock „ masuve,
Disconumuties are often hlled by hvdrochcrmal deposn,  f
o
Huarr/ VQns
permeabdm value for such rock ma,etui is typ.caUy u> .he order of less .han 1 a 10 > m/s and i»
generally impervious. Such nek material can hinder techier
\
. r . 
. ^’ernugr, enhancing run -off rather than
,
in fill ration Basement rock units found in the protect ilcu
, 
- ,       , r
, . 
.
tin  •* c°nsidcred as insignificant
aquifer marenal and to form an aquiclude.
UH F4 SRtMC Geortdi Pm 1 ’•)
14 hUfUvlv-
L’B IM SR04C Gcotcch Pin 1 (1)
97
14 Mty-11s'
lithcf"* Nl* Irrrrto* V**
Aquifer Types
t
....
The   aquifers   in   the   Upper   Bdes   proposed   dam   ate,   reservoir   and   imganon   command
therefore be classified as.
. Aquifers with inter - granular permeability these are the unconsolidated to
consolidated sediments associated with river deposits and colluvial / rcsid|la|
soil overburden material
•         Aquifers   with   fracture   permeability:   such   aquifer   material   is   the   weathered   and fractured basaltic rock unit found exposed in the area
•         Insignificant   aquifers   and   aquicludes:   these   are   the   massive   basement   rock   unit, dolcnte, tuff, silty clay and clay soil material found in the project area.
9, J            Aquifer Properties and Productivity
There is insufficient hydrogeological data in the project area to accurately determine the eitmt,
nature and properties of the aquifer materials. I iowever. based on the field geolog)* and
hydrogeological surveys earned out in the project area as part of this feasibility* study, aquitcn ic
the dam site, reservoir and command arei arc considered to be of moderate to low productivity.
The prevailing hydrogeological units arc expected to be characterised by moderate to low
hydraulic conductivity’ and transmissivity.
The hydrogrologKal units covering the area arc nver deposits, alluvium, colluvium / residual
reworked soil material, pyroclastic tuff, basalt, sub-intrusive dolcnte dyke and basement rock
units. The alluvia) and colluvial / residual reworked soil overburden marerial, tuff, dolcnte dyke
and thr basement rock units including the massive basaltic rock units are of low hydraulic
conductivity with low, insignificant productivity and non-watcr bearing.
The loosely consolidated and unconsolidated nver deposits can be considered as potential wiiei
bearing layers of good productivity, but the extent of such deposit is limited bring confined to
areas along thr Main (linat) Beks nver and its major tributaries.
Based  on  the  (soil)  surveys  carried  out  as  part  of  thi*  feasibility  study  the  hydraulic  conductivity of  the  alluvium  and  colluvium  /  residual  reworked  soil  material  vanes  from  about  10  5    m/s  to 10 • m/s, and may largely regarded as srmi-pcrmcabk or impermeable
Based on previous work done by others and literature, the typical hydraulic conductivity’ for the tuff, dolentic dyke and basement rock units is usually kss than 10 * m/s, and is usually considered to be impermeable with little recharging occurring.
The weathered, jointed / fractured and vesicular basalt „Kk fonn$ , p<Jteil(laj
surveys suggest it is likely to be the source rock for well, m the Command Area The few available well data indicate that yield of such aquifer material is tn die order of 1.5 1/s to 4 1/s Indicative values of yield and specific capaat, aie provided in Table 7-2 and the basalt in the Command Area is likelv to classify as low to m.iderate producunn
an d well
The current ground water level m the project area is lhlUow k
below ground level, and commonly less than 10 m. The water table responds to precipitation
5 4Q m
UH F4 SRWC Geotwh Parr 1 (1;
98
W-Mny-il94
a nd during the wet season the water level nses between 2-5 m For shallow wells the depth to water table is commonly just 2 to 4 m late in the wet season and 7 to 12 m late in the dry season (Source: local people having dug wdb).
Aquifer recharge apparently has decreased over the past thirty years (BCEOM, 1998). 'Die cause 15 pot dear but one hypothesis is that deforestation / land clearance for agriculture is the cause, increasing runoff and reducing infiltration
Groundwater Recharge
Only a small fraction of the annual precipitation percolates downward, a major portion runs oft o n the surface or is lost by evapo transpiration and evaporation. Downward percolation to the ground water reservoir depends on the intensity, duration and seasonal distribution of rainfall, topography (slope), vegetation cover, humidity and characteristics of the soil cover. It is greatest during the wet and humid season when rainfall is high and evaporation low and soil moisture is at or above field capacity Recharge to the deep buried aquifer is not influenced by short
periods of drought and such aquifers yield water even when shallow wells become dry
Groundwater flows comprise recharge and discharge under systems of local and regional groundwater flow. This involves vertical infiltration recharge through surface soils, flow through the aquifer under local or regional flow systems and surface discharge to drainage lines, i.e. streams and springs.
Rainfall data are tabulated in Table 9-1 and Table 9 2 below.
Tabic 9-1: Pawi Station Monthly Rainfall Data (mm
Date
RainfaO
Dale
Rainfall
Date
RainfaD
Date
Rainfall
Jan-87
31.6
Ian 92
-9999
Jan-97
0
Jan-02
-9999
Feb-87
0
Feb-92
0
Feb-97
0
Feb 02
-9999
Mar-87
0
Mar 92
9999
Mar 97
2.1
.Mar 02
-9999
Apr F
36.1
Apr 92
572
Ape-97
312
Apr 02
-9999
Mav 87
185.6
Mav 92
71.4
.May-97
147.4
Mav-02
-9999
|un-87
374.1
Jun-92
175.9
Jun-97
180.4
Jun-02
9999
_ Jul-87
290.7
lul-92
337.8
Jul-97
330.8
lul-02
-9999
Aug 87
246.1
Aug-92
481.6
Aug-97
383.3
Aug-02
9999
—*2 87
187.1
Sep-92
238.9
Scp-97
175.7
Sep 02
■9999
Oa 8^J
175.8
Oct-92
199.8
Oct 97
170
Oct 02
9999
Nov-87
0.6
Nov-92
9.1
Nov-97
16.9
Nov 02
9999
D«-87
9999
Dcc-92
9999
Dec-97
9999
Dec 02
-9999
___ |an-88
0
lan-93
0
Jan-98
0
Ian 03
-9999
J^BB
15.3
Feb 93
0
Feb-98
0
Fcb-03
-9999
__ MarJBS
_      _    2.7
Mar 93
8.2
Mar-98
9.8
Mar-03
9999
_ Apr-88
___ ___ 0
Apr 93
34.5
Apr-98
9.6
Apr-03
9999
— 88
_ ___ 104.7
Mav 93
112.2
May 98
153.6
May-03
9999
- Jun-88
____ 390.2
lun-93
321.4
lun-98
5113
Jun-03
9999
__ Jul 88
___ 441.7
lul-93
3705
lul-98
384.8
Jul 03
-9999
( ’oxcch PJr1 i p)
99
14-May 11Date
Date
Aug SB
Jkt-88
452-1
125.1
Oct-93
Aug-98
Oct-98
Nov 98
pg infall
366.6
1467
5.6
Date
Aug-03
Scp-03
Oct-03
^oy-03
Nov-88
Dec-98
-9999
Dcc-03
Ian 04
Fcb-04
Fcbj?
Mir-89
Feb?* 
Feb-??
Mar ?? ._
Mar-04
Mar 74
Apr-99
Apt-89
Aprjj.
1547
[un-?4 
207-2
J807
280.9
May-04
Jun 04
-9999
Jul-9?
2857
|ul-04
Jub89
4733
Au^74
304.6 
Aug-99
359.2
Aug-04
Aug- 89
Scp-B9__
3482
421.2
s S£°t
9999
Sep 99
2216
Scp-04
Oct 89
(kt 94
Oct 99
134.6
Oct 04
Nov-89
Nov 94
Nov 99
J97
Nov   0-1
Dec 89
lzn-9j
Feb-90
Mar 90
Apr-90
Mat 90
Jun 90
J°L^
Aug 90 3665
Dec-94
Jan-95^
Feb-95
Mm 95
Apr-95
May-95
Jun-95
-9<W
0
99*99
Sep-90
Og 90
Nov-90
Dcc-?o
Ian-91
Feb 91
4119
2313
433.6
248 1
Dcc-99
JmtOO
Fcb-00
Mar-00
Apr-00
May-00
lun-00
Aug 00
JW 0
0
2.1
617
1887
264.8
2009
365.3
3307
133J
0
_w
0
-9999
9999
9?99
Sep-00                  1767
Jkt UP
223.8
Nov-UO                 9999
p«w
fan-05
Fel>05
Mar-05_ Apr-05
.Mav-0?
Jun 05
Jul_05
Aug 05
Sept i5
Oct-05
Nov-05
Dec 2s
Jan 96
Fcb-%
Mar-96
Apr-96
May-96
Dec-00_
Jan-01
Feb 01
Mm 01
Apr-01
9999              Dtc-OS
W9
9999
9999
7999 -9999 -9999
-9W -999?.
■U -9999
9999
J?2?4 _J_ n2L
u
206.9
9999
-W9
-□099
[ul 96              370.5
Mav-Ol 9999
.Jun-01 Jd-01
Aug 91
Sep 91
>999
W
Dec 91
NW - »X ~ daSs
9999
Aug 96
Scp-96
O«96
Nov-96
Dec 96
5517
Ocr-91 9999
Nov 9) 9999
Aug
Sep 01
Ckl-Ot
r
Jan 06
FcMHS
.Mar-06
Apr D6
May-06
Jun-06
Jul 176
Aug-06~
Sep 476
Oct-06
Nov-06
Dec 06
66JK2. 2614 -9999
9999. -9099J
UB F4 SRW : Geordi Pm: 1 [1)
1U0
14-Majl1?<»**•* ^'""7                  «* twT»
J ""
------ —
areal rainfall
Month
Dam & diversion
weir (left)
Divereion weir
("«•><)
Main Bcle* (if
Bridge
January
13
1.4
1.6
2.0
20
2.1
Xtarch
124
12.7
145
Ann]
253
26.1
31.5
May
930
94.7
115.2
June
199.4
203.5
2392
lulv
3389
340.7
364.1
August
314.6
3153
342.8
September
186.5
1893
2236
()crol>er
94.9
96.8
115.8
November
13.8
14.1
16.1
December
2.8
3.0
42
-----------------------------------1
Annual |
1285
1300
L.471
Aquifer recharge is mostly linked ro rainfall infiltration In valleys recharge can occur through the watercourse (river / stream) bed where and when the water level is higher than the
ground water table.
The dominant hydrogeological units covering the command area are colluvial / residual Ar alluvial soil overburden materials. These deposits cover more than 80% of the area and dominate infiltration potential
From infiltration tests earned out under this feasibility study and from published data (BCEOM 1998;, the rainfall infiltration coefficients for geological units in the command area are likely ro be in the order of: (1) 0.05 (basalt); and (ii) 0.03 (alluvium, colluvial deposits, do lente and basement rock units).
Groundwater Discharge
Ground water discharge from the project area is mainly in the form of spring outflows and stream / river drainage
Fhe estimated long term average monthly flows for the Main (Enat) Upper Boles river at: (i) the dam site; (u) the drversion weir for the nght main canal, and (in) at the bridge at the southern pan ot the command area are tabulated below. Ihc annual averages arc 10.4 m'/s, 14 6 m /s and 55 9 m'/s respectively The monthly low flows roughly indicate baseflow discharges (and groundwater discharges) occur in April at the end of the dry season and arc 0.2 m'/s, 0 3 m'/s and 1 4 m'/s respectively.
Groundwater abstracted from drilled and dug wells forms a small proportion ot the baseflow / groundwater discharge. With reference to Table 8-8 above, current demand is estimated at 0.09
3
Gcotcch Pm I 0
101
14-May-llhtjrru.
RfwAfr                   Niailrf «fV attr & Ktriji
E/Aupwir NrA /rt^ufinw td
m'/s» This is 45% of the April bawflow discharge at the dam site (0.2 m’/s), an<] 6% Qf ( Apnl baseflow leaving the project area (1 4 m’/s).
Table 9-3 Long term average flows I m’/s)
Month
Diversion weir
(kfl) A Dam
Diversion weir (right)
B ,d£?
r
lanuarv
0.9
13
February
0.5
0.7
-                          2  fl
Mirth
0,4
03
____________ _ _
-                 2l6
April
0.2
0.3
14
NUy
0.6
0.9
.
38
,
|unc
43
6.1
July
26.(1
36 7
——J
134.5 ,
August
453
63.1
231 .d
September
28.9
41.5
164.7 |
lklnber
12,8
183
74.9
November
3.3
4 6
18.2 1
December
11
1.6
6.9
Annual
10.4
14.6
55.9
9.6               Ground* Ater Flow Direction
Groundwater flow is in form of vertical infiltration recharge through surface soils, flow through the aquifer under local or regional flow systems and surface discharge to streams, rivers and springs as well as seepage onto plains.
Based on the available groundwater level data from wells in the project area the groundwater table is between 5 and 441 m below ground level and commonly less tlian 10 nr
Generally the groundwater table follows topography and is high below ridges and low below valleys A simpbflcd topographic map is shown on Figure 1-2, and indicates that ground w’alef flow within the project command area is generally towards the Main (Enat) Beks river and generally from the NE to the SVC'. 1 fowever groundwater flow may also occur to the N-W over the escarpment into the Hyman (Upper Dindir) basin Groundwater flow into the project area is also likely to occur from the N-E and E from the escarpment separating the Beks sub-basin with die Tana basin
Superimposed on topographically controlled groundwater flow will be locally geologically controlled flow directions at geological boundaries and. for example. along basalt layer boundaries Most geological structural lineaments arc aligned NE-SVC suggesting the flow direction may be companmcntalised and from NF. to SW,
» Current groundwater u«e is ptotahljr a traction ul rurrent dertund
102
isrch 1(1)
14-May-11Mtety ofV'affr &E"*#
Ground" *tr' Qudfy
Ground  w»ter  quality  in  the  project  area  has  been  reviewed  and  analysed  as  part  of  this
t'cajibihty study with five water samples collected from in the project area (see Table 9-6):
•      Two at the northern end of the Command z\rea
•      One at the southern end of the Command Area, near Pawi
•      Two from boreholes at the dam site as part of ground investigation work.
Laboratory  analyses  earned  out  comprised:  Ca,  Na,  Mg.  K,  He,  Mn,  AL  HCO3,  CL  SO4.  CO3, SO3» NO2,1’. SiO2, HBO2, NII4, H2S, CO2, TDS, Total Hardness and pH
The  WHO  guidelines  for  drinking  water  quality  are  tabulated  in  Table  9-4.  and  the  Ethiopian Water Quality Guidelines for Drinking Water are given in Table 9-5
Table 9-4: WHO Guidelines for Drinking Water Quality (1984)
Paramcicfi
Guideline value
F
1.5
N’Oj as N
10
Al
0.2
Cl
250
Tocal Hardness as CaCOt
500
Fe
0.3
Mn
0.3
PH
6.5-85
Na
200
SO«
400
Turbidin
5.0
Total Dissolved Solids
1CMMI
Calcium
200.0
Magnesium
150.0
| Chloride
250
I «t results arc given in Table 9-6 and reported in Annex N. The results indicate that groundwater in the project area is generally potable, mostly complying with both the WHO and Ethiopian guidelines, although there is some exceedance tor ammonia and iron (dam sire only).
Lh|'4SR&’f
p art | /jj
103
14-May-HFtdmi
tfEfaptj. Mt turn tflTator C” E*trp
F.thicftM Xdt Ifri&ttca wd Dra^t fya
Table 9-5: Ethiopian Water Quality Guideline (after Continental Con«.t.
T<
Parameter
guideline
Value
~ ^002)
Remarks (advene effects)
True colour
22
Unpleasant appearance
'
()dour Ac Taste
Nor.-
Unpleasant to dnnk
~
Trmpcra’urc
objection
it4e
High temperature may enhance growth of micro organnm. A,                          —
taste, odour, colour Ac corrosion
n a may inr^^, -
*
Turbidity
7
Stimulate after growth & cause objectionable appearance
Aluminium
0.4
Deposition  of  aluminium  hydroxide  flocks  in  pipes  &  txacerbation  of discoloration of water by iron
Ammonia
2
()bicctionabk odour
“          ■
>,
(.blonde
533
Lndcsirable taste
' ****>
Copper
2
Increase  corrosion  of  Gl  &  steel  fittings,  staining  laundry  &  sanitary  wan- give rise taste problem
1 lardness
392
Based on 300 as reference WH() recommendation
Hvd. Sulphides
0.07
( ‘bjectionabk rotten egg odour
Iron
Manganese
0.4
0.13
Red - brown colour, promote iron-bacteria. Main laundr. & pluminng Wa Stain laundrvAc plumbing fixtures and give nse to undesirable taste to leverage Deposited as Nack precipitate in pipes. Certain microorganisms concentrate la give taste  odour A turbtditv problem
Dissolved Oxygen
-
,
Ixw IX) encourage for anaerobic reacuon & formation of N( h H;S giving Ck to odour It ahn increase FeQIj
PH
6.5- 8.5
High PH imparts taste & soapy fed, while low PH causes corrosion. Preferably <8.0 for effective disinfection
Sodium
358
Cndenrablc taste
TDS
1776
L ndccimblr taste
Zinc
6
-                  Mtringer.t taste & opile.r^.. and develop a vreasv film on boiling
Arsenic
0.01
n.£h meufext Of Skin * posubk other cancer,
Bi num
1.8
Boron
, Cadmium
0.3
0.003
--------- ----- *>—. <*_*u*pecT nt CArdiovAscijlar diseases
. _“lyrm exjxnure lead, tngayirointejtma] imration Kidney » the main target organ of loxxm
Inertisc blood pressure A
ij
-
-
Chromium
0.10
- J-yyn'yniatv rupee of chromium VI;
| Copper
5
turbo,,, f               ,        _______ ,_____ „               _____
1 Cyanide
0.07
* xxity 15 high Effects on thvrrad & particularly the nervous system on _ long - term exposure occunrH
Huonde
3-0
002
Al high concentration increases nd j . . n
« nik of dental fluorous & much higher concentration leads to side til fluototu
fUMi io oom ux central A ’le-n^k-. i
Magnesium
0.8
t
.. - . :—- —
!>!lcni _________________________________________________________ _
------ ------------------- '------------
.Mercury (total)
0001
The kidney is the maw Target f,*    _^                            ----------------------------- -
. . the cmml n                                  Pnn Hg whereas mcthvl-mercun'
trk
trvx
main Is the central nervous system
Niuare asNot
50
Neurotoxicity and other toxic rff^, Quire, ettacmoyilobinaenu. in mtinl5 atl||
Nnntc as N’< )j)
6.0
—S2*L!}Hpeci of certain form of cancerflgU
Selenium
0.01
| Long lem> explore cmuq toxic efferTZTT^----------------- ~------------------------- ------- ——^L^Jhau and Lver
UH F4 SR04C Gmtvch Pan 1 (!)
104
14AUv -11f LT^f**** t\7&
J*7Vn/ll-lff Prwrrf
Table 9-6: Water quality frat result and THO guideline and Ethinpian guideline*
r
Parameter
•
J WHO guideline Higbeat
desirable
Ethiopian
guideline Highest
desirable
SI (well ID 17
northern
command area)
S2 (well ID 20
northern
command area)
S3 (wett ID 15
smith of Pawi in
command area)
S4   (BHVJBD7   i dam site area) I
S5 (BH UBD2 \
dam site area)
1
| Turbidity(NTl’}
Tr
Tr I
12
S3 beyond limit I
TDSfmg/1)
1,000
1 776
337.0
388 0
405.0 1
82.00
226 00
EC(uS/cm
517
*211
T 625
118 00
34800
PH
6.5 8.5
8.5
T03
U
" 39
688
736
Ammoniafmg/l)
2.0
0.19
0.94
1 32
247
1.97
S4 beyond limit
Sodium(mg/1)
200
558
20.0
42.0
39.0
9.00
52 50
1 Potassium mg/l)
0.3
0.3
1.0
5.70
4.30
Total Hardness (mg/l)
500
392
256 5
2585
257 5
43.70
76.00
Cakiumfmg 1)
200.0
79 04
95
76
1368
1900
Magnesium (mg/l;
150
50
1426
4.6
20.7
2 28
6 84
Iron (mg/l)
03
0.4
0035
tr
tr
1.95
0.74
S4.5 beyond limit
Manganese mg/1)
0.1
0.13
Ftuorideftng/I)
15
3.0
1.0
0.73
0.76
072
0.91
Chk>ndc(mg/I)
250
533
0.9
5.4
9.9
I 82
1.82
Nitnte.mg/I)
6
tr
.0005
tr
□ 08
0.02
Nitrate''mg I)
45.0
50
098
1.12
0.94
I 87
069
Alkalinity (mg/l)
283 5
346 5
346.5
62.70
174.8
Carbonate (mg/l)
nil
nil
ml
nil
Nil
Bicirbunate (mg/l}
34587
422.7
4227
7649
21326
Sulphate (mg/l)
400
200
028
0.28
0.19
8 70
452
Phosphate mg/l)
0.30
0.32
Aluminium (mg 1)
rul
Nil
Boron l^rng/l)
0013
0.013
Co; (mg/1)
2
f
tr = trace; IDS - Total Dissolved Solids l05 C, nl = nil, EC = Electric Conductivity l H K4 SR04C G cotech Part 1 (V
5
105
14 May 119.8
dcp
^  dunum. colluvium I resxlual sod overf^
s
TXokme dvke »nd the basement rock units and based on the cuncn,
nUl 7 t 1 and avadable data there is moderate to low ground water p
hydrogcolopc«sun .
project ire*
» k«»* 
otcnrial ft%
de 1“’"s' “d ,h'
*”<l
XX «        -* *• * *w * “Xp ,x„ „—. * ™»-    **”• ”d “ ■"w
h ,-to* 
ta «<W I
3W d„k.,r I «M «< •* «"*» *• I”’""
”? '""T*
opretrf
o> fc uorai'oUxrf »'■“* 
ta
5
extensive.
The projected potable water supply demand for the project area is 0.13 m /s. With reference to Tabic 9 3 above, this is 6S% of the April (base flow} discharge at thr dam sire (0.2 m’/')> and
9% of (he April (baseflow) leaving the project area (1 4 m'/s) measured at the main road bridge over the Main (Enn) Belts over at the southern boundary' of the project area.
In theory the projected potable water supply demand could be met by sinking productive tubcwcUs tiiougb out the project command area However this faces the following uncertainties / problems.
• The extent of productive aquifer (tc pretence of weathered and fractured basaltic rocks), which would support reasonable yielding boreholes (i.c about 1.5 l/s for 20 m drawdown) remains uncertain and quite likely only extends over a portion of the command area,
. Demand by the rural populsBon u scattered m small senlemenrs and isolated homesteads throughout the command area, and
. In contnst demand by the urban populanon B concentrated in the mam Voted,
^nlemems, includmg Week Med., bendlka pw Fw
po „bk
water may have to be p.ped in. possibly from a surface source ro meet demand
Demand by rhe sugar factor and assured seniemcn. area wdl also be co.rcentnted To meet future poubk wate supply demand inch»4.n„ « .
..
’ K water requirements of the sugar factor,
r
~
a mix of water supply sohiimns is required to rmL^r ik- „ 
.
j l ti n
‘
.
current widespread use of streams an
d
unprotected springs and shallow wells, fhc mix » tf| Reasonably sized potable witer supply svstrm. .
r
\k
v
the sugar factory, whereby water is d!Vcrecj q
.     ' ™ lor *<• major urban areas as well >< >or
z
”
piped to the point of use with intermediate Morale flow required for irrigation my surface water diverted
^°WS’ Ucltr^ 41U
P foPorUo° nl 1 *
1 if< 14 SR<W<* C’Oicdi Part1 fl
supph use will be negligible (<1%). Specifically tt -         ™              ‘ P°tlblc u>arcr
“ * ^^d that the sugar factory
ItZ.
H Msy-I1Mriiftry ITatr & Earryp
will divert and treat water from the Mam fl’**nat,c5)mR« culrp« str~eam of the proposed
.
factor}’ location;
. B.«hok. 20-60 m deep rf ™,„„
rr
„   dus.cn   of   horned,   depend^   ™   .-ell   neld   U.   Urge,   borehole,   „v     „„   beve a simple distribution system; and
. Protected spring, and protected shallow wells up to about 15 m deep mostly serving single homesteads.
Potential Impact of Irrigation on Groundwater System
The irrigation command area is characterized by shallow ground water generally found at depths of 5 40 m. with the shallow depths largely founded in topographic lows. i.e. the plains. During the wet season much of the lower lying areas, largely vertisols, become waterlogged
Groundwater flow, as indicated by the low April flows in the Main (Enat) Bcles river at the southern boundary of the command area is just I 4 m Vs. This is just 2.3% of the average dry season irrigation flow for the proposed development of 63.8*’O ba of about 60 m /s
With the irrigation project and the seepage and application losses from canals and fields respectively, infiltration and recharge to the groundwater aquifer would increase, possibly as much as 150-200%. A greater increase is very unlikely given the semi-impervious nature of the soils and underlying marginal aquifers. Baseflow from the aquifer system with the project would therefore be about 2-3 nP/s as measured at the southern boundary.
Irrigation during the dry season for double cropping and / or to enable sugarcane cropping, will potentially seriously aggravate the water logging problem as there is limited n a rural vertical drainage and low hydraulic gradients over most of the command. Soils largely comprise cracking ulry-diy to clays which arc underlain by bed rock units, in particular the massive volcanic rock, dolcnte and basement rock units, of low hydraulic conductivity. When wet, the soil swells and cracks seal up making the soil virtually impervious.
Careful water management to avoid over-irngation, and provision of surface drainage to improve runoff of surplus water following rainfall, is therefore necessary to avoid w'atcr logging.
3
10?
14 May 11t. «<f>*** M""'D vV*'r
*
COMHf^V AREA geotechnicAL parameters
10        [fltroduction
*' ubo^" *sCn« °f 5dCC,ed lnd fePreScntttive **> ‘*npl« ftom trial plts m the Command
Irrigation Area has been conducted using the Water Works Destgn and Supervision Enterprise
tfWDSE) laboratory' service tn Addis Ababa. Details of the samplmg and
of tc,Ong
vt provided tn Section 3.5. The test results are provided tn the Annex Lof this report.
The geotechnical parameters for each soil type tn the Command Irnganon Area have been determined from the laboratory test results and correlations in published literature The test results are summarised as Figures I to 17 in Annex B. as detailed in Table 101. The main geotechnical parameters derived for outline design purposes are summarised in Table 10-2 and Table 10-3
Tabk 10-1: Command Area Parameter Plots in Annex B
Figure
Description
Fy^ire Al
Moisture content against depth
Figure A2
Plasticity chart
Figure A3
Effective angle of shearing resistance against depth
Figure A4
Particle size distribution curve
Figure AS
Percentage of each grading constituent
Figure A6
1       Linear shrinkage against depth
•
Figure A7
Swelling pressure against depth
|
Figure A8
Compaction curves
Figure A 8a
Compaction curves - Vertisols
Figure A 8b
Compaction curves - Red/Brown Sflt/Clay
Figure A9
Shear stress against normal stress
Figure A10
Undrained shear strength against depth
__ Figure All
Coefficient of volume compressibility (m,) against depth
Figure A12
Coefficient of consolidation (c,) against depth
^figure A13
Penneabdirv against depth
figure A14
Organic matter content against depth
F, l?ure A15
Sulphate control against depth
2*gure A16
pl 1 against depth
_______
A17
Mass loss on ignition against depth
----------
has not been undertaken on samples of rock in the Command Area, but comments are about rock parameters m Section 10.9 based on core logging and observations of
roc k exposures.
f^lcch Pan j (l}
14-May-11
109I fdm>. Dcfwauft* fafuMc Estep* 
rflT^rr c> finffp
Ertefm N:ir
and Dnajt«<f Prwt
Table 10-2: Natural Moistur
e Content and A tier burg Limit Results
PU»oc Limit (•/.)
Liquid Limit (%)
Nntural Moiati}^ Com
Materia)
1 Mm
Max
Average
Min
Max
Average
Min
Max
Vertisols
27
45
38
70
10B
85
16
51
27
Red/Brown
Stir/Clay
23
50
37
36
77
GO
5
60
36
YdSow/Grey
Salt/Oar
28
34
31
50
56
53
21
43
2?
Weathered
Bedrock
NP
MP
NP
35
.LL
45
12
27
2,1
10.2 
Topsoil (TS)
Topsoil should be removed prior to construction; therefore parameters have not been determined for this stratum-
10 J Vtmsofr
r
The Vertisols are generally described as very stiff dark grey / black clay of ven high to
extremely high plasticity, occasionally desenbed as silty or gravelly.
The plasticity chart (Figure A2) indicates the material classifies as either very high or cxtrcmcl; high plasticity clay, with a liquid limit range between 70 and 108% and plasticity index betwee: 30 and 67%. Average, maximum and minimum values are presented in Table 10-2 Figure A2 demonstrates the difference in plasticity between the vertisol clay and the other common soil type, the reddish brown silt /clay.
At the time of sampling (December 2009 to January 2010) the natural moisture content (NMC was mainly between 15 to 31%, below thr plastic limit, with two samples at slightly greater depth with NMC of about 50*4 (Figure Al). This suggests ihaf moisture content may increase with depth but there is no definitive trend visible for variation in moisture content with depth lor the tests earned out It should be noted however that moisture content is likely to change seasonalh and may have been affected due to the time itvpicallv 1 day) between excavating thi inal pits and sampling, and then the time between sampling and testing
[;B |?4 SjuW. CJcntixh Pan Id)
no
t4-May-iu-j.
....
Bulk
1 density'
<Y->
mmunu rucu *
Effective
ingle of
■hearing
resistance
tel
jewire nnu a
Effective Cohesion
(<=’)
■ raranicierB
I'ndrainrd
■ hear
■ trength
(cu)
Optimum Moisture Concent *
and Maximum
Dry Density
Compaction |
requirements.
Moisture
content range
Linear         |
Swelling       l Pressure 1
Coefficient of \ volume               1
compressibility I
Permeability \
%
I
M</m’
Degree!
kN/m1
kN/m’
%
—I
1
20
kPa
M-/MN
m/s
Vertisols
1.9
18
0
60
OMC 24.5%
MDD=1.56Mg/m*
OMC 2.5 to
OMC+6 5
65
0 20 to 050
Unfissured
-uia7
Fissured
=1x10•
Red /Brown
Sdt/CJav
1.9
25
0
75
0MO31 5%
MDD -I 47Mg/m’
OMC -25 to
OMC+5.0
11
15
055
______________
—
Ln fissured
—SxlO7
Fissured
=lxlO4
Yellow/Grey
Silt/Clay
20
25
0
75
-
10
•
0.05
5xlO7
1
1
Colluvium
2.0
28
0
-
-
-
•
-
-
IxltP
Weathered
Basalt
2.0
28
0
L
•
-
-
-
-
1x10 1
________________
L'B F4 SK04C Gcoicch Part 1 (V
111
14-Mav 11FrtAfti/
Afnturp kWWrr <> Ewp A'jJr J.rr^jjDon a*4 D«*4f ?rwft7
Based on correlation between shear strength tp’ and the plasticity index (Pl) (ref <)j indices lest results indicate a range of ended effective angle of shearing resistance tp^  f
t          r   fQ
'
7
17° to 24-5® with a mean and median value of 20° (Figure A3). A moderately conservative value ofip'cw = 18° and effective cohesion (c) of 0 kN/nf can be adopted for oil dine dr*
Particle size distribution tests in the vertisols (Figures A4 and A5)> show rhe dominant parr^ size is clay with approximately 32% to 94% clay content. Silt sized parades comprise between 4% and 52% of the stratum. The remainder is generally composed of a very small fraction (typically less than 10%) of sand or fine-gravel sized particles. The mean values of the dominant grain sizes arc 74%, 19% and  % for rhe clay, sill and sand /fine gravel respectively
Fifteen linear shrinkage tests gave values ranging from 15% lo 23% with a mean and median of 20% (Figure A6) Three swelling pressure tests were undertaken giving results of 13.5%, and 100% (Figure A 7), the latter two results being very high These results indicaic the materia] is likely lo undergo rigmficam shrinkage and swelling with variation in moisture contenT This is a well known properly of vertisols and is observed from large dcticcatiofi cracks in the projcci
area.
Sn compaction tests were completed on rhe vertisol stratum (Figure A Sa). The opmiHun moisture content (OMC) vanes from 24.25% to 27.50% and a low masurium dry density (MDD) varying from 1.45 io 1,56 Mg/m’ An OMC of 24.5% and MDD of 1 56 Ng/nT are selected for design purposes. Assuming a parade density of 2.8 Mg/m*. compaction can be undertaken between approximately OMC 2-5 to OMC +6.5 to achieve 95% MDD, Hie moisture con lent (MG) vanes. from 16% to 5l% (Figure Al) therefore this marerial may require weiring or drying prior to being eomparred, which may be pracucally difficult to achieve
No bulk density tests were undertaken on this material. From the description of stiff plastic day. it is likely to have a bulk density in the range 1.8 Mg/m  to 2-1 Mg/m  (ref 10) A hulk density of I 94 Mg/m’ can be calculated for the proposed compacted material from the data given above. A bulk density of 1.9 Mg/m  can be adopted for outline design.
Fifty-hand vane tests, each composing the average of a set oi three results, were undertaken in l he uial pH w alls to measure the undrxined shear strength of the vertisol day. The results range from 48 kN/m  (firm) lo 140 kN/m  (stiff) with a mean of 113 kN/m  (sufl) and median
1
1
J
a
3
J
of 131 kN/m  (stiff) (Figure AID). However great caution should be taken in design as du* ^T*
3
of material varies greatly m strength with moisture contenL Therefore a moderately conservative design value of 60 LN/nr nw be adopted for outline design There is no trend apparent for variation in strength with depth
Five laboratory permeability tests were undertaken on ihr Vertisol matenaJ resulting in low values ranging from 2.12x10* m/s tn 1.16x10" m/i Figure ±313). This is a typical value for
inr/Jr/wrec/ clays and clay-nJis (rtf 11). Where desiccation cracks occur nearer the surface jn this nutcrul, a much higher permeability of the order ranging between 10-m/s to 10 "m/s might he expected (ref 11). For outline drsign purposes a nv*drraidy conservative value of lx 10 m/s
t -J4 1-4 SRMC Cienrech |1arl 1 (U
112Minify, W attr &
bc assumed for the material where „ is not &surcd and
though this will vary greatly depending on the fissure apenure ,nd connfctmly
So consolidation tests were undertaken on this material. From conelanons u^tli undrained shear strength and plasticity indices (ref 12), a moderately conservative cocffiC1Cnt of volume compressibility, m„ value of 0.20 to 0 30m’/MN can be assumed for outhne design purposes
The organic matter content ranges from 0 05° « to 4.3% with the mean of 14 tests being 2.4%. The results show a reduction in organic matter content with depth 'Figure Al 4) These results mdicate the stratum is quite high in organic matter and may still undergo decomposition with omc lught samples were tested for mass loss on ignition which gave a range of 10.5% to 13 6% with a mean of 11.4%.
Fourteen samples were tested for the sulphate content. These gave values ranging from 00002’ " to 013'’" o with a mean of 0.05" a. The pH of three samples was taken giving a range from 6.2 to 7.8 with a mean of 7.3. This gives a Design Sulphate Class for the stratum of DS-1 and an Aggressive Chemical Environment for Concrete (ACEC) classification of AC 1 (ref 16).
10J Ked/Brvn-n Clay/Silt
The Red/Brown Clay/Silt is generally described as a stiff to very stiff reddish brown silt/day, occasionally noted to be gravelly
The plasticity chart (Figure A2) indicates the material classifies as intermediate to very high plasticity sill, with a liquid limit range between 36 and “"7% and plasticity index between 13 and 42%. The majority of the results plot bdow the A-line indicating the silt partides arc more dominant. Average, maximum and minimum values are presented in Table 10-2
At the tunc of sampling (December 2009 to January 2010) the natural moisture content was found io be extremely variable, between 5% and 60° o, at about the p las be limit The moisture content is shown to increase with depth (Figure Al) for the tests earned out suggesting a desiccated surface However, the moisture content may have been affected due to the time (typically 1 day) between excavating tnai pits and sampling and then between sampling and testing. Also the moisture content will change seasonally.
Based on correlation between 9’ and the plasticity index, Pl (ref 9), the plasticity indices test
f csuJt5 indicate a range of critical effective angle of shearing resistance,
21 5 to 30
with a mean and median value of 26.5° (Figure A3). A moderately conservative value of !p’ « =
c
25
° effective cohesion (c ) of 0 kN/nr can be adopted for outline design However,
1
^•entic soils can break down further when re-worked and further assessment is necessary at detailed design stage.
P’nide sec distribution for the reddish brown silt / day (Figures A4 and AS), shows the ’“Want particle size is day, although the clay content is ven- vanable ranging from
’PP-r-urnately  o
6   /o ,o 85% 
$|2e(J ffacuon ls
vanable at between 13% and 64%
° f ,hc
Ibe remainder is generally composed of a very small frac non (typically less than
14-Mny-ll
0)
113Dtfljwvfi* R/paWrc of            Ab«/m a/ 11 jfrr t E "'T
Ef/icpM* Sil/ Jrnrafi'H and DnnMg Prwrrf
10%) of Sind or finegrivd sized particles. The mean values of the dominant
45%, 38% and 17% for the clay, silty and sand / fine gravel respectively.
Nineteen linear shrinkage tests gave values ranging from 1.7% to 8 .3%, tile larrer bong a ff value, the second highest value being 20. ignoring the spurious result, the mean and median arc 11% (Figure A6). Six swelling pressure tests were undertaken giving results ranging frorn 3% to 27% with a mean and median of 15.5% and 15% respectively (Figure AT). These rnuhs indicate the material is likely to undergo a degree of shrinkage and swelling with variation in moisture content but to a lesser extent (han the vertisol material
7
Five compaction tests have been completed on samples of the reddish brown silt/day (Figure A8b). For design purposes an optimum moisture content (OMC) of 31.5% and a low maximum dry density (MDD) of 1.47 Mg/m’ arc considered appropriate. Assuming a particle deadly of 2.9 Mg/tn’, compaction can be undertaken between approximatdy OMC -2.5 to OMC 1-5.0 to achieve 95% MDD. The moisture content (MQ of simples varied from 5% to 611% (Figure Alj therefore this rnatenai may require wetting or drying pnor to being compacted, which may be practically difficult to achieve.
Five bulk density’ rests were undertaken on this material giving a range from 1.73Mg/m  to 1.91 Mg/tn’ with a mean and median of I.RMg/m’. From the desenprion of stiff plastic day, tr is bkely to have a bulk density m the range 1 BMg/m' to 2.1Mg/m  (ref 10) A bulk density of
3
s
1 93 Mg/m' can be calculated for the proposed compacted material from the data given above Therefore a bulk density of 1.9Mg/m’ shall be adopted for outline design.
Twenty four hand vane tests, composing the avenge of a set of three results, were undertaken in the sides of trial piB to measure undraincd shear strength (Figure A10). The undrained shear strength ranges from AOkS/m* (firm) to 140ltN/m’ (stiff) with a mean of 102kN/m’ (stiff) and median of 99kN/m  (stiff) (Figure AW) However great caution should be taken in design as this type of material vanes gready in strength with moisture content. Therefore a moderately
2
conservative design value of 75kN/m  may be adopted for outline design.
1
Seven laboratory permeability tests were undertaken on the reddish brown silt/clay sod unit
resulting in low values of permeability ranging from 1.27x10* m/t
to 5.08xl(>   m/s
7              (Figure
Al3). Thia is a typical value for
cfoy ad da^/ilu {ref II) and is similar to or slightly
7
higher than the values found in the vcrasols. Where desiccation cracks occur nearer the surface in this material, a much higher permeability of the ordrr ranging between 10 Ws lo WW» might be expected (ref 11). For outline design purposes a modenrely conservative value of
5x10  m/s may be assumed for the matrnal where it u not fissured, and 1x10W* where it i* fissured, although this will vary greatly depending on the fissure aperture and connectivity
Five consolidation tests were undertaken on this material pvmg high values of the coefficient of volume compressibility, m., ranging from (J.233m /MN to 0 592m’/MN with a mean and median of 0.36Om’/MN and 0.339 m’/MN rcipcctndy (F^ure At 1). A moderately conservative tn, value of UASOm’/MN can be assumed for outline design purposes, lire ran^ >n coefficient of cunwbdauon, c., 0 0m’/yt to S/W/yr wih . mon .nd med urn of 217m7f»
2
UB F< SR04C Gc«r<tfc P«r ’ < '
r
111
14 Mag-116>**‘
,„d l-M^’/yr respectively- A moderately conservative eoeffioent of volumc
viluc of 2 Om’/yr an be assumed for outline design purposes,
Ct»
The organic matter content ranges from 0.5% to 3.9% with the mean of 13 tests being 1 6%
The results show a reduction in organic matter content with depth (Figure A14). Ihese results
^dicate the stratum ts quite high in organic matter and may soil undergo decomposition with
nme Eleven samples were tested for mass loss on ignition which gave a range of 6.5% to
12.44 • with a mean of 10 4%.
Twenty samples were tested for the sulphate content. Ihese gave values ranging from 0 0001%
to 0.274% with a mean of 0.07%. The pH of five samples was taken giving a range from 5.3 to
5,9 with a mean of 5.6. This gives a Design Sulphate Class for the stratum of DS-1 and an Aggressive Chemical Environment for Concrete (ACEQ classification of AC-ls (ref 16).
YeUow/Grcy Chy/SUt
The  Yellow/Grey  Silt/Clay  is  generally  dcscnbed  as  %  a^atberrd  basalt  nconnd  as  a  stiffytllovssh m/bnm slightfy jiruwlfy clayey silt".
The plasticity chart (Figure A2) indicates the material classifies as intermediate to high plasticity
silt/clay, with a liquid limn range between 50 and 56% and plasticity index between 28 and
34% Average, maximum and minimum values are presented in 'fable 10-2. Only three samples
were tested, so maximum, minimum and mean values should be created cautiously.
At the time of sampling (December 2009 to January 2010) the natural moisture content was
between 21% and 43° o, at about the plastic limn The moisrure content appears to increase with drpth (Figure Al) for the tests earned out However, may have been affected due to the time
typically 1 day) between excavating and sampling and then berwecn sampling and testing Aho
moisture content is likely to change seasonally.
Based on correlation between and the plasticity index. PI (ref 9). the plasticity’ indices test
results indicate a range of crincal effective angle of shearing resistance, y’em, from 25° to 2K
with a mean and median value of 27° and 2B° respectively. A moderately conservative value of
r cm - 25° and effective cohesion (c*) of 0 IcN/m  can be adopted for outline design.
Pirtjclc  size  distribution  (Figures  A4  and  A5).  shows  this  unit  to  be  highly  variable,  and  with  no measurement of gravel content recorded
N ° impaction tests or bulk density tests were undertaken on the Yellow/Grey Clay/Silt 'tratum froln ,hc dcscnprion of stlff sbghtly ph.tic to plastic day. it is likely to have a bulk dcnsit>’ » the range 1 8 Mg/m  to 2.2 Mg/m’ (ref 10). A bulk density of 2.0 Mg/tn' can be
2
5
^fjpted for outline design.
° ne ' ane test, composing the average of a set of three results, was undertaken giving a ' hc« length of94kN/m» (stiff) (Figure A10). However caution should be taken as there is
’ F<S?.(W-r
14 May-1 1
115Ffrtfrd/
fU*     rqfE/iir'ijrvj, 3lr«tJ/g p<IT*r.,rr <*" E«rp
EMptaa Nijr I^fjriotr dai Dnnnapf Pfvjttf
only  one  test  result  therefore  a  moderately  conservative  design  value  of  75kN/m7   b the logging desenprion of ‘stiff may he adopted for outline design.
Three to  Shnnkage tests gave vd«s ranpng  from 7.6%  to  14.29%, the. m«n Jnd m, ItT o  and 8%  respect^ (Figure A6). No  melting  pre*™  tests were undertaken. The results indicate the iMitml is Ukck tn undergo a  degree of shrinkage and swell,ng  with variation in moisture content but to a lesser extent than the Vertisol and Red/Brown Cl material
No  permrabilirv  tests  were  undertaken  on  Hus  material.  The  permeability  of  rvn/w j               Limtna generally is generally of the order 10 *m/s to 10 "m/s whereas the pen
at9
of unfuntnd 
day-n7/.<is generally of the order 107m/s to 10 ’"m/s (ref II). For d
purposes, due to the sand and silt content and the permeability of the overlying material moderately conservative value of 5x10’m/s may be assumed for this maicnaL
No  consolidation tests were undertaken on this material brom correlahofts with undraii shear strength and plasticity indices (ref 12}. a moderately conservative irk value of 0 05i may be assumed for design purposes.
’!lie organic miner content ranges from 0 9% to 1.4% with ihc mean of tests being I® (Figure Al 4) These results indicate the stratum docs not have a high in organic matter, an indication of the units’ derivation from the weathering of bedrock < )nc sample was t for mast Jos* on ignition, lhe result being 1 0®/b.
Two simples were Irsied for the sulphate content. These gave values of 0 OCX)!0  o to 0.2’ pH samples were taken. 'Phis gives a Design Sulphate Class for the stratum of DS-1 (ret
[0.6           Rivet and Snentn Dcporii*
The river and stream deposits arc only cncountcrrd in the base of lhe river channels and These have not been sampled. It u unlikely my construction will be undertaken with thi: stratum as the foundation male nil there fere parameters have not been determined
/ft 7 CaRtwum
The colluvium is generally drsenbed as grey cobble silty gravel No tests were undertake dus material therefore the following perimeters hive been taken from literature baled or desorption-
The 9' of* granular soil is generally retired lQ Us dcn<[fv i, ,l
H wnll he assumed the m««ul is
A
‘
.      ,.
*«“ *>'
kN/m  may be adopted for outline dcsjgn
J
Dr «ervam c \ alue of -28 and <
Compaction tests should be undertaken on tjus materia! poor ,o using ii as fill
I P4 SR0*C GeoK-eh Pm t 4)
1H
14-.•
H H'afrr &
J
J
From the description of a cobbly silty gravel, the material ts likely to have a bulk density in the range 1.8Mg/m •«> 2.0Mg/m> (ref 10). A bulk denstty of 1.9Mg/m may be adopted for outline design
The permeability of vtryjinf sands. jilts and clay silt laminate generally is generally of the order 10 4m/s to 10 ’m/s and the permeability of ckan jandi and sandgnvrl mtxtxns is generally of the order lOAn/s to 10 *m/s (ref 11). For design purposes a moderately conservative value of 1x10
^n/  may be assumed for this material
5
jFrj/A cred Bnsah
The highlv to completely weathered basalt is generally described as being recovered as
completely weathered basalt, recovered as a grey clayey silty sandy subrounded to angular
GRAVEL of basalt often with cobbles and occasionally with boulders
No  tests  were  undertaken  on  this  material  therefore  the  following  parameters  have  been  taken from literature based on the description
The •/ of a gTanular soil is generally related to its density*. As there are no tests for this material it will be conservatively assumed the material is loose'. A conservative value of<p’=28° and c' = 0 kN/m  may be adopted for outline design.
Compaction tests should be undertaken on this material pnor to using it as nlL
From the description of a clayey silty sandy cobbly, bouldciy gravel, the material is likely to have a bulk density* in the range I RMg/m’ to 2 OMg/m’ (ref 10). A bulk density* of 1 9Mg/m3 may be adopted for outline design.
The permeability* of iwj fine sands, silts and clay-silt lamina generally is generally of the order 10 *m/s to 10 m/s and the permeabihtv of clean lands and sand-£ruvel mixtures is generally of rhe order 10\n/s to 10 m/s (ref 11) For design purposes a moderately conservative value of 1x10
*m/$ may be assumed for this material.
J
4
109  Bfdroek
No laboratory testing has been completed on the bedrock units, but most of the command units are interpreted to be underlain by generally similar strong volcanic (basalt) or intrusive (dolemc) rocks. A field description of ’strong' equates to an unconfined compressive strength 'angtng from 50-100 MPa
Exposure is limited and the units can be vanable, particularly widi respect to imnting and w ^'henng Therefore specific investigations of the bedrock will be required at specific
Picture locations at detailed design stage
,Po,«h I’m 1 (l;
14-May-11
117up#; 4 
„ & I"9‘ ”’
^'">'0 «/          c> Etng)
r
l) 'a ”^f P’^nr
dam site area geotechnical parameters
11
J.J
II1
testing of selected and representative soil and rock samples from the dam site area *becn conducted by Addis Geosystems Co. Ltd (AGCL) using the WWDSE laboratory. In h >! the following in situ tests have been conducted in the drilled boreholes at the dam site:
1        . Standard Penetration Test (SPT);
•      Falling head and constant head permeability tests in soil materials; and
•      Single packer Lugeon tests in sound bed rock units
The sampling and methods of testing are desenbed tn Section 3.6. The tests results are provided
in Annex E and Annex H of this report
Based on the test results, pubhshed literature and prev.ous experience, interpretation of the tock .nd sod geotechnical parameters has been determmed for feasibly stage design purposes
1
At detailed destgn stage further testmg and confirmatton of these parameters wdl be required '
Summary Laboratory Test Results
A summary of the laboraton' test sample locations is provided in 'fable 11-1 and Tabic 11-2. In addition to rock core from boreholes, bulk samples of basalt and tuff from proposed quarry sites were collected for comparison and determination of suitability for rockfill. Three potential basalt quarry locations arc shown on Drawing UB/FS/GEO/10/02 (see Figure 3-5).
Summan laboraton test results for soil samples from boreholes and trial pits are provided in fable 11-3 and Table 11-4 respectively. Summary laboratory test results for rock core samples are shown in ‘fable 11-5, and for quarry’ samples in Table 11-6Wnl Drmmto R/piba.- rEfaafu, Mimitq o/V j' fr CEwy
Etbi^ian Siit Imi^on j«J Dfrinqt Pw.r
Table 11-1: Soil Sampling Details from Upper Beles Boreholes
Sample
L’BD 02
Sample Depth
0.600-80
2 50-2-80
4.00445
100 1.20
1.70-2.00
4.50 5.00
8.00-9.00
1.00 1 20
140185
2.80 3.45
4.60 4.80
1.20 1.45 6.31.00
L0O-4OO
6.30-700
9.00 9.50
1100-14 00
iyojlfi.25
21.30-22.30
2620-26 60
29 40-30.00
KH-l 45
10 00-1045
5.40-6.00
6 60 7.00
R00 10.00
ioo-ijL 2 90 -335
Sample Type
(D=disturbed,
U~Uodbturbcd)
S’mpleDc.criptio,,
_     SandvCUy-
_S»ndi CLAY~
SihvSwd^Gni^
Sandy CLAY~^
Elaycv SKF~
Srnd
Silty SandyGnwT
Glavey SILT
CobHv GRAVE! Cohbiy GRAVE!.
Clave-. Silt Sandy GRAVE].
Sih CLAY
Silry CL\Y
Silrx SAND
Cobbh GRAVEL
Sandy GRAVEL
Silrv CLAY
Silty CLAY       |
Sandy (TRAVEL___ I
Sdr.- S-AXD
_
Cobble GRWEL        I Sdry  GRAVEL SitnGRAVEL
Table 11-2: Rock Sampling Detail, from Upper Beles Boreholes and Proposed Quarry
Site
Location
Sample ID
Sample Depth
Sam ok Description_______
1 65 2.25
Tuff                 __
Tuff           ___
BH I HD 01
1305 1538
23.7? 24 03
26.10 26.30
33.00-33.20
Tuff _ ____
Basalt           —
Basalt
lath Bank
BHUBD02
6.51-6.’5
_______ 13351141
Tuff              .   I
_
fuff      -
Tuff           ■—-—i
2245-22%
8.65494
BH UBD0”
Tuff                ___
________ 13-10-13.34
Tuff
17.44 17.65
Tuff
Right Bank
BH UBD 05
r~i214                   "7
Basalt
14.4 15.00
Proposed
tjuarrv sue
VPSQ 1
l’PSQ-2
Basalt
_
Surface expusurr
Basak 1
Tuff ___J
: Growth 1 (0
I iR F4 SR'M<
12H11-3: Soil iAbortiory tear results from borehole sample*
Grain size
B ore/io Jr                Depth
Attctburg Limit
Classification
Dispersibility by
double
hydrometer
Method / pinhole
Sulphate content
extract (tom •oil (mcg/1)
Moiiture content
linear Shrinkage
Unit '
Weight
(gm/cc)
BH UBD 02 0.5 0.6
10 12
36.84 21.00
F.27 21 05
25-2.8                                                                                                                                                                                             3547         1951
4.0 4 45
BHUBD04 1679
1.0-4.0
5 4 6.0
63-7.0
9.0-95
ND i (Pinhole)
NDtCPinholc)
38.67
37 64
20.85
Silts .Sandy Gravel
Clayey Silty Cobbly'
GRAVEL
Clayey Silty Cobbly
GRAVEL
Silty Cobbly
GRAVEL
Clayey Silty Sandy
GRAVEL
Gravelly Silty
CLAY
Dt (Pinhole)
ND i (Pinhole)
11.9-
1235
Clayey Silty Sandy
GRAVE
13 0 14.0
523)1
Gravelly Silty
CLAY
NDi (Pinhole)
17.8-
18.25
21 3-22 3
Cobbly       GRAVEL
ND4(Pinhole]
& Gravelly SAND
Gravelly Silty
SAND
UH P4 SR04C Gcotcch Part 1 ;i)
121
14-May -11f rdrni/ DtwMvwirr Rp-Mr Afau/r, •fVttrr t* E^
Eibttf^n N7A Jrni^M Jltd 1)^^ f^.t
1 26 2-26 6 1
55
1266
45 23
16 61
Cobblv GRAVEL
—
NDi(Pinholc)
•
-
29 4-30.0
15.0 1
36 86
48 14
ND«(Pmhole)
-
-
-
♦
________________
BHUBD05
_
! 1.0 145
Clayey Silty Sandy
GRAVEL
, 4.0 L
11.32
818
1
76 5
Clayey* Silty
gravel
NT)j(Pinholc'l
-
•
20.66
-
| 29 3 35
1 ----------
95
16 11
103*’
6402
Cobbly Clayey Silty
Sandy GRAVEL
ND.(Pinhole)
633.3
3201
31 32
32.97
26.9
32.97
■
1
1
1  6.60-7.0
0 44
7.52
I 35.07
56 97
Cobbly GRAVEL
28.72
18.87
9.85
-
| 8 0-10.0
Fine Gravct=0 Ofi
-
Medium Gravel -3.13%
-
-
Coar*c Gravel—96.79%
GRAVEL
-
-
-
B!< I BDD6
i-----------
1.0-1.2
-
-
ND
56.05
36 38
•
23 38
-
-
1.7 2.0
-
-
•
ND
59.52
36 11
-
15 61
3.4 3.85
-
-
ND
34 38
27 84
-
35.7
4 5 50
8.0
15.93
76 07
-
Sand
-
-
-
-
-
8 0-9.0
00
242
3.27
94 31
Silty Sandy Gravel
-
-
-
-
•
-
-
-
-
-
-
-
-
IIIKTBD07
1.2 1.45
— "------ -
-
-
-
ND
107.95
44.12
-
-
35.7
r
2 8-3 45
-
•
-
•
ND
94 14
4432
49 82
-
-
17.64
|
46-4 8
-
-
l—l
-
ND
8330
30 41
----- —_ __
5289
•
-
14.20'Table 11-4: Soil iaburattiey test results from Lriisl pit
Fi
Iff
’
--U---B---D---P---t---  ""-------------------------------
UBDP2
UBDP2
liBDPJ
UBDPJ ~T                 UBDP4
UBDP4
(O-J.OO)
(0 40-0 40)
(0.40 2 00)
(o-o.as)
(0.05-2.00) I
(0-1 ao)
(t.ao-2.00)
(Cohesive AU)
(Colluvium)
(Colluvium )
(Colluvium)
(Residual Sail) I
(Tetrace Ge.)
(Terrace Ge.)
I Grain star analysis
1 Chy ?/.)
| Silt (%)
Sand (%)
27 50
4842
2408
32.00
31 37
3665
58 5
25.75
15.75
48.00
42 47
9.53
Gravel (%)_____________
Afterburg Limit
Ijquid limit (%)
Plastic limit (%)
7388
27.56
87.17
45.29
6220
4079
102.55
44.21
62.75
31.59
59 07
33.91
49 90
27.89
Plasticity  Index  (%)
Dispersion by Double
46.42
43.88
21.41
58.34
31 16
25 16
HOI
Hydrometer____________
ND
ND
Linear shrinkage (%)
".52
1697
NMC__________________ Compaction
12 11
.37.28
675
2426
22 73
MDD - 1.635
()MC = 22.50%
r Permeability (cm/»cc)
1.47  IQ 6
x
Parameter
UBDP5
UBDP5
(Colluvium)
(Colluvium)
Grain     size     analysis
CUyf.)
Silt (%)
Sand (%)
Gravel (%)
Atterbuxg Limit
(0-1.50)
4550
43.16
13.34
(1.50-250)
46 00
53.56
20.44
Liquid limit (%)
Plastic limit (%)
Plasticity Index f° •,
65.94
54 45
29.49
ND
53.60
2933
24.37
Dispersion   by
Double
Hydrometer
Linear      shrinkage
(%)
14 54
12 04
NMCf -j________________
2683
22.69
LB 1*4 SRQtC Gcotrch Part I J)
123
14 May-11Fei~±
ofE/hfta,
of 11 jfrr <* Emiq
Ettwpwi Silt Jfftp&M and DrxtJft l'w.1
Tabi  le 11-'5: Rock laboratory teat remits from borehole aatnplea
Strata
iuic u .
Sample
ID
Depth of
sampling (m)
Water
absorpl
ion
o*y
density
(jj/cTn3)
Moianire
Content
(%)
Porosity
(%)
ucs
(MPa)
T
T
T
B
K
T
T
T
T
T
T
UBD1
UBD1
UBD1
UBD1
UBD1
UBD2
UBD2
UBD2
CBD7
UBI)7
UBD7
1.65 2.25 13.05 13 38
23.77-24 03
26.10-26 30
33.00-33.20
6.51-6.75
B.15-1341
22.65 2190
8.65 8.94
13 10 1334 1*44-17.65
128
1138
40.77
•
11.52
948
844
9.03
8.43
5.71
1532
1200
1296
1020
1307
1.972
1194
2.250
1159
2.378
1291
0.98
5.74
22.33
-
1.23
6.28
3.93
7.75
4.80  |
3.87
1 6
124
116
-
-
0.84
138
2.1
3.65
189
1.58
29.8
3.5
45.3
46.0
25 4
205
205
170
20.5
KNtal
25405^
156rji
-
•
-
-
-
___________
Xo/ft: T = Trf, B = Baja//
Table 11-6: Rock laboratory test results from qimrv samples
Sample ID
Dry Density              Water Absorption
IJPSyiJBasak^ 71_______ 22)62
UPSy2 ffuff] * 
2,155
’ olu-
9.00
Porosity (%)
0.63
17.90
Slake Durability
____ ---------------------
9W
99.34
Teat type
Sample ID                   ———-
UPSQ1 (Basalt)
UPSQ2(Tun)
Soundness loss In Sodium Sulphate \SH1O T-104
1%
__ ______ —
K^rcgate Crushing Value [BS 812 part 11(1)
17%
_----------
Ten percent fine valor tn wet ccodiaon (RS812p*rt 11'
230KN
H0KN__-J
1LJ Top Soil
Topsoil in the dam site lira is thin, typically 0.1 to 0.40m thick and occasionally absent II i« stiff dark brown to greyish dark sdtv CLAY to slightly sandy claycv SILT It is assumed that material will be stopped and removed poor to construction and therefore is not assessed further. No geotechfuc.il tests have been completed on this matrnal
11.4 Cohesive Alluvium
Cohesive alluvium is found along the Bdes
.      ...
it ,
° floodplain and in topographic lows OI
.        ..
...
plain land where vertisols have develuDrd h •« <4\
r krh
l I »i            i t <*i
described as finn tn very stiff dark grey to dark
..
rr
sbghrh -sandy ^dyg«vdy, ,yCL.
a              W(lt
d.^ j
S  LTofblghplijocih.
The  foundation  beanng  Qjndtjr  of  this  materuj  u   bkd,....
unsurtable for .uppomng rockfil] dara
.Ihrvrum ha. been found to be non drspa,^ ind |
° ** lnd « “
UB F4SR(MCGer
arch 1 w
124
14-May11F^f* M"c"rf **
g.-n^*'’
10 U' rjj]ev
rt ^ ^um 7 RiVCr Te,nce D"PO"i,!l
bottom it is difficult to distinguish granular alluvium and nvcr terrace deposits and l ^C osc* of this investigation they arc grouped together. Terrace deposit has been
tOf    *   j   «   significant  thickness  along   the  slope   of  the   nght  abutment, encounter^
The material comprises variable sands and gravels and arc pencrall 1
*" ** 
Cfi.ll EL
w/
ww
J.'lAU, ptunbh clam
Filb.g / constant head permeability tests were condoned in thts unit summansed in Table I1-7. Results may be unreliable as thev do 
k,
n. . 
be
groundwater table and therefore in unsaturated soils.
Table tl-7: Falling and Constant Head Permeability Teat Results
°
* VaKles
“
n c the
Borehole
Depth (mbgl)
Strata
Falling bead permeability
K, m/sec
0.00 200
Cohesive alluvium
3.3x10'to 8.3x10'
0HUBDO2
200-4.45
Granular alluvium
1.1 x HP to 2.4 x 10'
0.00 2.00
River Terrace / Colluvium
1.5 x IO5
BHUBD04
5.50-7.50
River Terrace Deposit
7.9 x IO4 to 4.5 x 10'
18.80-21.50
River Terrace Deposit
3.6 x 10* to 3.6 x 10 J
0.00 3.35
River Terrace Deposit
4.1 x 10 *
BH IUD 05
6 50 8.00
River Terrace Deposit
33 x 10* to 3.1 x 10’
8.00 10.00
River Terrace Deposit
9.8x10’to 4.5 x 10*
BH UBD 06
0.00-200
Cohesive alluvium
7 9 x 1(P to 2.6 x 1CH
BHUBD07
4.00 5.85
Cohesive alluvium
5.6x10* to 1.7x105
The dam design will need to include an impermeable cut off through this material to prevent
excess leakage and flow, f urther investigation of the material is required to asses composition in more detail for dam shoulder slabiliry and seismic liquefaction p< conservative assumption for feasibility stage design is to assume that the material unsuitable foundation strata requiring removal and replacement with rockfill improve compaction
Colluvium/Residual Soil
*
Hie dim abutment slopes and reservoir slopes weathering and leaching products of the underlying processes    The    colluvium    is    described    as yellowish grey stains slightly boulderv cobbly vcr) h Hfctenal thickness is considered likely to be
covered by the  combined i’owckit,th’ 5
gmcntS
°Pe
^(
h p^sh     ’*’"
br<           40
dense    ,oclAY
to 
&W    SlLT
serial
but
^thappn^^
Pinicle sue analyses indicate the variable cotnpO!>^v to bc non d»pe»‘ve »nd geflewU' equal proportions of silt and clay, 1 he material
* SXUC Gentedi Pin 1 (I)
14 May 11
125DrfflCOTXrf
L’/fvjjtai n N74f AW*/
Minty rfV '*tr cF Eanji Fnyr.r
pcrmcabilnv, but dur to the variable nature of gravel content, the cut off beneath the da
should extend through this material
TufTRrdrock
Tuff is found at the Dam Site left abutment and in rhe Reservoir Area,  it is moderate^
!tlQ
or  strong  greyish  pink  to  grey  slight  to  moderately  weathered  massive  to  ven'  closely  |oinr d
c
Ethic possibly agglomerate (basalt and tuff fragments) TUFF. 1 here arc occasional zones of
highly   weathered   weaker  and   more  fracturrd   tuff,   and   possibly   also   some  layered   differCncc? matrix and lithic composition resulting in weaker paler hiff
Table 11-8: Lugron Test Results
Borehole
Teat Depth
(mbgl)
Strata
Water prcBBure ten;
Luge on Vahic
2,20 ro 7 JO
Slightly weathered tuff
H
7.20 to 12.20
Slightly weathered ruff
3
Bll UBDOI
(lx ft AhutmrnTj
1120 to 17.21)
Highly wciuhcrcd tuff
60
1720 Io 2220
Highly wen tiered tuff
1
22.20 to 2’ 2>
Fresh ruff / basalt
40
27.20 to 32_2
Basalt
30
10.00 to 15.00
Highly weathered tuff
I
15.00 to 20.00
Fresh tuff
1 __ _______ _
20 00 to 25.0(1
Fresh tuff
1.
BH UBD 02
fDam Axis Center)
25.on to MOO
Frcih tuff
6
50,00 to 35.00
Fresh tuff
s
35.00 to 40.00
Fresh tuff
1
40-00 to 45.00
Fresh tuff
20 _______
45.00 m 50.00
Fresh ruff
4_____________-
1000 to 15.00
Mod. weathered tuff
15-00 to 20.00
BHUBD07
(Saddle)
Slightly weathered tuff
<1 J
20.00 to 25.00
25 00 tn 30 00
Basalt
<1 -
Basalt
<1 —
JCUXHo 3 MX)
Basalt
<1 -
Fourteen Lugeon tests have been completed in rhe tuff bedrock (Table 11 8), with value* ranging from zero to about 60 Lugeotu. Values do not correlate well with weathering grade although the highest value occurs in highly weathered tuff There is no apparent decrease in
l.ugeon value with depth The tuff therefore has generally Enw. occasionally moderate permeability properties with Utile leakage anoapaTrd through this strata
11jc Unconfmrd Compressive Strength (UCS) conducted core samples from boreholes t
02 and 07 w as found m range between about 17 and 46 MPa, classifying the material a* nuiiub moderately strong
VH F* SRtMC Grnrech Part I J ■
126
i4-M*y 11111
tuff is censored to be a suitable foundation matenal for an embankment rockfill dam for b«nng capacity and sliding resistance, but fitnher tnvesnganons are required to assess areas of h^hly hercd dW'ly ’O,nted mff m grC’ICr d',al1 Groun<J trcatmc"' may be required to
jeduce leakage potential
g^t Bedrock
js found to underlie the tuff at the left abutment and apparently to form the bedrock at tht right abutment, although further investigations arc required It is also found in isolated
itches in the Reservoir Area where it is tentatively interpreted to be denved from intrusive sdls Basalt is also found more extensively on surrounding hills, some of which have been selected as potential quarry sources for the rockfill to form the dim
It is strong dark bluish grey to black aphanatic to at places vesicular medium to closely jointed basalt
Five Lugeon tests were conducted on the basaltic rock unit encountered in boreholes UBD01 and 07 ar the left abutment and spillway. At UBD01 values arc moderately high (30 and 40 Lugeons). At UBD07 values are less than 1. This implies that the material is semi-pervious to water tight However, the lower than expected values at UBD07 may also indicate that the test was not functioning corrccdv at this borehole.
I CS (Unconfined Compressive Strength test were also conducted on the basaltic rock unit in borehole UBD01 (Table 11-5). ’Inhere is one spunously low result of 3MPa that is likely to richer be an error or an invalid test, and one result of 45MPa which is equivalent to moderately strong. This is lower than has been determined from field observations, and further assessment should be made at detailed design stage
The basalt material forms a sound foundation with an adequate bearing capacity for dam is sound with respect to the intended structure to be imposed on it Considering water tightness, the material is found to be semi - pervious to water right. Consequently, it may not cause
excess leakage along the dam site.
hike the tuff, the basalt is considered to be a suitable foundation material for an embankment tockfill dam for bearing capacity and sliding resistance, but further investigations are required to assess areas of highly weathered or closely jointed ruff in greater detail For feasibility stage design, grouting of the basalt to reduce leakage should be assumed due to the potential for the
°ck unit to be highly jointed and to potentially contain higher permeability paleosoils.
1 b ”alt Io<* material is found to be a generally better quality than the tuff and is a mote
u,, able rockfill material. In particular the water absorption and porosity properties of the basalt ^uch lower than those tn the ruff, and the density is higher (Table 11 6).
14 May 11
127FuM Drwwnift. RrpM; ofElbi^a, Mhilirt tf^ 'strr C E/&pWir Nri lrr%jtwn <ud Dram? Pyj
1L9       Dote rite Intrusions
The dolente exposed in the over channel at the dam site is strong to very strong shghj weathered dark blue grev medium to fine grained medium to closely jointed DO] i;d r material will not affect foundation design but could affect permeability and leakaw j
dam and for feasibility stage design it should be assumed that grouting is required to potential intrusions that could have lughcr permeability and leakage potential, due to fra gmund that could develop around intrusions Detailed investigations should provide forth assessment of the number and locations of intrusions beneath the dam
lfBF4SRO«’c;c<Mech p*n 1
12#
14-May11«/£**“• Sl" “
u
r>
12
1
geotechnical design issues
Th>< section identifies the key geotechnical issues affecting outluir
feasibility of’ * project
An  outline dam design is presented in the Supplementary Report SR (MB Engmeenng • Storage P,m This includes some detailed geotechnical assessments, including dam shoulder slope ability analysis Therefore in the sections below this work is referred to but not repealed, and onh ., summan of these issues is presided below.
T
^2  ype
\  detailed  discussion  of  the  rationale  for  dam  type  is  presided  in  the  SR04B  report.  A  rockfill embankment  dam  with  an  asphaluc  clay  core  and  cementitious  grout  cut-off  has  been  selected f of the following reasons:
•     The valley* profile is nor suited to a concrete arch dam.
•     ’I’here is no nearby source of cement for a concrete arch, concrete gravin' dam or concrete face rock fill dam;
•     Rapid drawdown of the reservoir could occur, which could destabilise the upstream shoulder of an earthfill dam or upstream clay seal;
•      Rockfill may be more consistent and more plentiful than suitable carthfill matenals in the area;
•     There is interpreted to be a plentiful supply of basalt nearby that would be the most suitable rockfill material in the area;
•     Foundation strata (assuming superficial materials are stripped off) is predominandy incomprcssiblc tuff or basalt which will be suitable for a rockfill embankment dam;
•     There may be an absence of a plentiful supply of suitable clay material in the area with which to form a clay core seal, and therefore an asphaltic core is proposed instead;
•     An asphaltic core also has properties of self-healing and absorbing deformations, which could be advantageous if there are faults or rapid changes in geology beneath the dam thar could result in differential settlement; and
•     Seismicity in the project area is low, but never-the-less, a (rockfill) embankment dam with an asphaltic core is one of the more robust designs against seismic deformanon.
Foundations
I ’unabtHti
found investigation work carried out as part of this feasibility study has identified a more
a  ^Plcx and more variable underlying geology* at the dam site than was originally interpreted SurflCc capping alone, with the following features affecting the dam foundation design.
The left abutment predominantly comprises moderately strong ruff, but this is variable Wh occasional zones of weak tuff that is also often more closely jointed, due to cither: ft differential weathering (at vanable depth); (ii) differing composinon / layering within lhc  tuff; or (iu) potential proximity to faults / zones of deformation.
Underlying the tuff at the left abutment is basalt; it is currently unclear if this is inclined P^alkl to the topography or sub horizontal as one or more layers, in uhich case it
14 May-11
129Ft<M                 R^urZu?.-             Mmt/A? «/ V a/fr & H wqp
Etiw^rrff Mar Irr^fiog jfw/DnrOfip Pf9fKt
be faulted / downthrown between boreholes. The base (and hence th v basalt has not been proven. 
At rhe Central Valley no basalt has been found underlying the tuff tn i
t
'
4e
Oepth, nf s."
However, there is a dolentc dyke visible in outcrop and therefore intrusion
or basalt bedrock should be expected elsewhere beneath rhe dam
At the nght abutment an unexpectedly thick profile of super Eda] deposit |r
sands and gravels) was encountered, varying from about 10m thickness bene ‘ |
upper slope to more than 30m beneath the lower slope. The profile of the s *
unit beneath the lower slope is not clear and could be related to terrace gravels • paleochannels or to a previous topographv related to faulting.
Beneath the nght abutment the solid geology is interpreted to be basalt, bur rhe location and form of the boundary between basalt and tuff that occurs lx tween the central valley and nght abutment is not clear.
Phnro-hncamrnis appear to align approximately S\V-N1< through the dam site (pinU to the valley and perpendicular to the dam axis). with the possibility that there are fault zones beneath the dam Mo such faults hive been found in outcrop or intersected b)
the boreholes, but geophysical survey results show unexplained vertical features beneath the dam axis,
At detailed design stage, a detailed ground investigation is requirrtl that should include investigation of rhe Icatures above. The dam design should also include sufficient flexibility to accommodate the potential vuunons listed above that would be identified during cons trucTjcirt from (i) excavations and bedrock inspection lor gallery and cut off construction, temporiiiy diversion structures or dim foundation treatment; and (if boreholes formed for grout injection.
. J2       Ktmowii of Supt/fawl Mair rials
At die left abutment superficial deposits are either absent or interpreted to be thin (less
about 5m) and to comprise variable colluvium, or residual soils. These are unsuitable foundation material* that should be removed lmtn beneath the dam footprint
In the central valley there is a slightly thicker sequence of cohesive alluvium, granular alluvium and possibly leoacc gravel and colluvium al die valley edges On the left side superficial deposits are shewn Io vary from about 5ru to more than 1f)ni (probably less than 15m depth On the nght side the depth of superficial deposits has not been determined but is expected to be similar,
Die cohesive units nr unsuitable and should lx removed The granular units may be sui«hk they can he shown to be deme and ool Ia be mixed wnh days Otherwise these marrEals
should also be removed. A cut ofi trench to bedrock is required due Id thr permeable nanit* the granule deposits An assessment of liquefaction potential is required at detailed design s«gf for any granular rmicniis left in situ beneath rhe dam footprint
At the upper nght abutment there n about 10m thickness of <aitds and gravels (rivet terrace gravels) ovedaxn by a thin cohesive unit of colluvium The cohesive upper layer is uns^rabk
C
1'0 F*
SR&4C <irufrch  *
r
n 1 '
>4 M«y-i1•        A#**"**
l.^
d  <houM be removed .Again, the granular units may be suitable if they can be shown to be af 5  J not to be mixed with clap, otherwise they should be removed
jcnse
u
the lower right abutment there is over 30m thickness of sands and gravels (river terrace
\ds) a *uff sdty da)' £c°m lbOUl ° 60 (° 15 ,Omdc
P  (*  borehole UBD4) Many of
Ac
sand units in the lower sequence (22 to 30m depth) arc described as fine grained. Due to the l^u shear strength of the clay and liquefaction potential of the fine sand, and depending on the selected dam option, this deposit may form an unsuitable foundation stratum that will require ether removal, ground treatment, a slackening of embankment dam side slopes.
|. or the current feasibility study, it is assumed that this maienal will be removed from beneath the dam footprint for the larger dam options, but will not affect the Option D design where it is beyond the requirement to place an asphaltic core.
iTie bedrock in the area is predominantly moderately strong lithic or agglomerate tuff or strong basalt Both rock types should provide excellent foundation material to support embankment dam construction Ihcrc is however potential for fracture zones, faults or more highly weathered weaker ruff to be encountered during excavation for the gallery / cut off, as well as more open jointing in the upper 5 to 10m. and here additional excavation and consolidation grouting is recommended
12/ Djtm Site Construction Materials Assessment
The construction materials that are needed for the intended dam are rockfill armourstone rip rap and granular transition filter materials. A review of potential clay sources is also desenbed below
/W fackfiU
1 he basalt outcrops forming hilltops surrounding the dam site have been assessed as providing better quality and more suitable materials for rockfill than the lithic / agglomerate tuff found at the dam site and reservoir area The dam body will therefore comprise layers of quarried rock HU basalt rock, the selection and placement of which is further desenbed in the SR04B;
I ngineenng - Storage Dam report.
lests on quarry samples show that the basalt is denser, with a lower water absorption value and much higher 10% fines value than the tuff (Table 11 6). The basalt is therefore considered to be more durable. A single UCS test on basalt core resulted in a value of 45MPa, which is lower
Ulln aP«ted Field observations indicated the UCS of the basalt to be about 50MPa to (strong) or 100 to 250MPa (very strong) Further assessment of the strength of the
Mli < is required, but it is currently considered that the basalt will have sufficient strength for
»s rockfiU
potential basalt quarry sites have been identified, summarised in Tabic 12-1. The quarry ^own on the Geological Map of the Dam Site and Reservoir -Area (Drawing
lB 'B/GEO/,o/o .
2 mFw,„„).
14-May-H
131De^,.
,X-,fc J„^,„ jbW nrjr^
PotenMtiidal|
| Approx
DiMance to | Dam Sice I
I
Quarty Site
8c Elevation
(mail)
II
I
I
Quarry Site I |
O264O53E 12925nN
'km ESE,
1.550mas|
0262659E
Quarry Site 2
1293444N
1.5 km E
1.472masl
Rock Description
Very tUong slightly weathered dark grey fine grained aphanitic BASALT I-argt columnar jnmting in 2 sets. fl). vertical.
I T*cing 0,5m — t 5m tight to open up io | 3 5cm no infill, rough planar (ii). 80/85.
spacing 00 2 - 0 5m, tight to open, up tn '.Ckm no infill, rough planar.
Strong dark grey * fight to m<xle rarely ' weathered fine grained BASALT,
I commonly close to verv closely jointed / fractured, occasionally medium to widely spaced joints 2 major sets perpendicular verticil Slight to moderately weathered with dark and reddish brown coatings. aperture tight to open up to '.OOcm
————
Outcrop Description
Other Issues
No overburdrn
< bain like basalt ridges, very large outcrop 1 Fractured boulder floats up to 1 to 2m covering toe of the ridge In - situ well jointed basaltic rock can be extracted as medium to large and some very large
blocks
Excellent r<»ck ifuaiity visually assessed.
At penphety of villages
Access roid required, feasible with no major issues
Possible npping extraction No evidence of gruundwater Sample collected foe testing
Some gravely to cobbly sod overhurden
1 Lib formed of basalt
Fractured in situ blocks and boulder Can be extracted as small to medium and few large blocks
Good rock quality vf’ually assessed
’ Farm land with no settlement
I Arces* road required approx 1.5 to 2d km. feasible with no major issues
’ Possible ripping extraction No evidence of groundwater Sample collected for testing
Quarry Site 3
I 2594?5E
( 1295528N
2km NW
I
without secondary infill mat eml___________ _ Strong dark grey fresh to shghtlv
weathered aphanitic close to widely
I jointed BASALT. 2 joint sets (i) vertical, I tight to open commonly ’em, no infill
spacing 0 I to 0.5m (ii) perpendicular to | t    s  o  et X Q.30m) tight, few open (<1cmj spacing 0.7
No overburden
Chun like basatt ridge, very large outcrop Medium to widely jointed and massive.
I arge to very large size rock blocks
, possible.
Excellent rock quality visually assessed.
Pcnphcry of ullages
Access road required approx 2.5kxn feasible with no major issues except on wrsr side of river
Possible ripping extraction No evidence of groundwater
i
I
JiL—.———blocks of columnar basalt from Quarry Sites I or 3 could be used to form armoursione Alternatively there are exposures of massive tuff bedrock in the reservoir area that may be suitable
There is no single consistent source area for sand and gravel materials identified tn the vicinity o f the dam site. Instead, the following potential sources may supply some suitable mainly gravel
size aggregate rnatcnz
^  but further investigation would be required to confirm consistency* and
5
volume.
•      In the bed of (he Beks river and to a lesser extent the tnbutarv rivers are sand and gravel deposits; these arc probably thin and arc now removed or under water from the Tana Belcs HEP discharge;
•     Gravel size aggregate could be produced by processing basalt quarry run materials.
•      Hie preliminary ground investigation has identified significant thickness of granular alluvium in the valley bottom and river terrace sand and gravel under the right abutment, however, both sources arc interbedded with clay materials and will have variable thickness and quality.
A reliable source of sand size material has not been identified in the project area
£4.4 Clay
Depending on the availability of suitable material, embankment dams often use day to form the impermeable barrier. The day is specified in terms of grading, plasticity, compaction density', shear strength, permeability’ and dispersiviry
The clay soils identified in the dam site area are not suitable or of sufficient volume and consistency and comprise:
•     Cohesive alluvium (silty day) on the Beks floodplain: limited extent and thickness (less than 3m) and probably variable composition;
•     Colluvium slope deposits: limited extent, variable, probably too gravelly; and
•      Vertisols downs cream in the spillway area: plasticity and organic content likely to be too high, too much swelling and shrinkage.
significant volume of suitable clay materials has been identified in the project area, and tor r ^son an asphalnc core has been selected. However, two potential sources of clay materials
birther afield are described below:
! ^Wnd.Xiei \Xerk Mrrla / J  ArM
w
,s
reddish brown silty day soil material found in the Command Irrigation Area and
tsc nbed m Section 6.4.3. It is located about 30 to 50km downstream and southwest of the in the vicinity of both Jaw, and Week Med. W depos.rs of this m.tenal were found
boreholes undertaken on the main canal route near I awt
p,„ ,
(1)
H-.May H
133Fwitrzr/ Owwenafl't         of jE/Aj-fltyj, Af/«t?/n p/lT^rr e^.Ewrp Efhi^'rJ* Nrir /mfjftiK Dnarrrj^ Pnpft.1
also no badge in this vicinity* to cross the Belrs River
access road may be available to link the two arras.
Yismala Giyorgis
A similar reddish brown silt day  soil has been observed to  be extensively  cover an 2itfl loc^rcd about H) to  14km NW  of the dam site in the locality  south of the mam road between Yismaln Gtyorgis and Belen town.  Apart from a  foot path,  there is no  access road from the dam site m the proposed potential borrow site and this would require a  difficult road construction down i steep escarpment and crossing  several tributary  valleys No  investigation has been made on rhe thickness or suitability of this material.
125 Embankment Slope Stability
degrees.  This  assumes  that  the  basalt  rockfill  will  be  durable,  high  strength,  well  graded  with angular fragments, free draining and well compacted.
Assuming (he basalt rockfill has i typical phi' value of 40 degrees, simplified slope stability'
gradient of 1V 1 ,RH in also typical of an internally-sealed rockfill dam on a ruck foundation
br  stable  The  dim  is  shown  to  achieve  an  adequate  Factor  of  Safety  under  several  opcraDr'jS condition^ including normal operation, rapid drawdown, reservoir empty and seismic loading-
preliminary seismic hazard issesiment (sec Section 12 10 aod Annex D) indicates that the din1 sire is in an area o! tow itosmicjty. In addition, mckfil] embatikrnrfli darns arc recognised as being a robust dam design that is generally resistant to earthquake loadings. Stability assr^sme^
UH].-*sr«<              Pin 1 (1
14 Aiiy H/A—’*-
fiifgesp that deformation and senlcment will fa Enluatinn Earthquake acceleration off)
'        0.1%to the cuno,,.,,
'"W'U,,*, «*,
■
Jt» important to note that the lability of the dam rcbcs
M d    the    use    office    draining    h.gh    permeability    rockfill    th^"    '"nov«J      <*    underhang    wils
assumed as representative in this assessment
At detailed design stage, the stability calculations will need to be
”” ihev Wngth parameter
detail the seism* stability’ determined from a full seismic analyst ,eUCtl tO Cf,nsidcr *n more
conditions and proposed rockfill parameters as determined k' 7 'hC KtUal found*D°n
works
’    ground investigation
Cf
!2g Dam Foundation Treatment (
Water-tightness)
b»d.
been l
oK d f„
„ fa
, K.,,d«,g up .<>
60 l up™. B»d
.lild, «, be ptrtneMr
jnd
”* =p«. ™,t of the b^
Lugoon .-doe,
,„ b.
„„ Ac
dunng (he prelimman- investigations testing was not possible.
Jhcrefore a series of pre-grouting water pressure fests should be earned out to confirm
foundation permeability values for injection grouting design. Consideration of foundation
sealing is likely to extend to a depth of about "5% of the dam height above foundation level
through exploratory holes
At detailed design stage an assessment is required comparing  the nerd to  prevent leakage with the cost of grouting,  taking  into  account the location of underlying  more permeable basalt and possible fault zones.
/J 7  Spillway Excavation and Design
The large dam options (A to C) require a spillway in a saddle to the left of the main hankment. whilst the lower Option D requires a spillway cut into the abutment slope on the
kftt.de of the crest
V.7;
SptfhHy (Optwuyl f0 Q
bedrock was found at approximately* 8m depth at the centre of the
dir faU 1X*S 31 ^°rC
lc                 7
^ °^  ^bDO  Above this depth there is about 6m of stiff high plasticity silty
P fofiie 1Uln CO^unum) overlying about 2m of stiff gravelly day (weathered bedrock). This rwbt^_             lo be consistent down slope on the downstream side of the saddle, or with
saddle
** VCrt1SO’s* but bedrock appears to be shallower on the upstream sk>pc of the
the^ j/ 0** flDm 8fn to about 19.5m is moderately strong to strong ruff From 19.5 to 28 5m
b lJltCrla'Cred and strong basalt, and below 28.5 to the base of rhe borehole at 35m is L  bedrock rises to surface to the west (to form the hill separating the spiDway
14-Mav 11
135FrAra/ Dt.-eo.ran.             s'W"® "■' U ar,r c" Evt&
lVr> JiTTjVfidi
PflJ/ft-*
from the dsun) bur geophysics suggest? that is it deeper to the cast, requiring additional
investigation in this area at detailed design stage
Excavation for the spillway will be easy in superficial deposits, but shallow side slopcs
IV: 3H maximum) will be required in the alluvial / vertisol clay materials. The clay marcrid^
will also be unsuitable founding or retaining strata with low shear strength> low bearingca
and high swelling and shrinkage potential and will be required to lx- removed from beneath
spillway channel or retaining walls
Excavation  in  ruff  and  basalt  may  be  difficult,  requiring  explosives  and  steep  channel  sides  cid be a turned of 2V:1 H or greater.
Groundwaler was encountered *t shallow depth in this area (between 2 6 to 12m, some readings possibly spurious), so provision for groundwater drainage should be included in thr outline design
12.7.2 Abrfiwti Stef* Sfufhtorj fOptww D)
To accommodate the Option D spillway into thr left abutment slope requires an approximarrly 30m high cutting that will be cut into tuft bedrock Eight meter high stage*- of 6V;1 II are assume with 4m wide berms. Detailed design requires further assessment of the rock mass and joint orientations
L2.fi Reservoir Water-tightness
Bedrock in the reservoir am comprises mostly Tuff (of gcoerallv low prrmeahilin') but also basalt and dderirc. with some palcosodl horimni observed. The basalt appears io he wrll- loinced and is likely to have higher permcabihtv thin the ruff In addition, faults through the area could represent high permeability flow paths. This would be significant if lhe topograph}' Eurrounding the proposed reservoir area could promote leakage of reservoir water into neighbouring nver banns. However, inspection of rhe topography indicates that nsk of leakage from ihe reservoir area should be very small, irrespective of the nature and distribution of [hr
basalt.
f ? 9          Oom Site and Reservoir Sfopr Stabffity
12.9. f       P-ww Jrk Jiy*/
llir sitq^csi slopes at the dam site occur
•      Al the upper section of the left ibunntm where there are detached blocks of lb*‘ appear to be susceptible to sliding and tb«r a evid „„ of searj creep
c
•  At the Belts River jutt upmeam of the dam JUs where [hf m e flow, through a 11^""'
.
gorge. pamc.daTlv <m (be left ude w
e   on!e coltu^] appclT [o br unstable and
h„  ]
supported by vegetation.
At the righi abutment the dam axis follow, a ridge and therefore, depend^ "n the height of
the dam and amount of superficial .oil excavation, th  don shoulders
c
m _, QO rop slopes
facing upstream and downstream, requiring further stability assessment
UHF+SRi*
r ’Jrt ' i”
Bfi
jj.Mar-l1SM "r'
Pn "**
M,o st *  *
e
ht lbutnien',hcrc 15 dun sod and vegetation cover and the slope, appear to be
Ull
‘ u$ceptlble to runoff erosion, requiring appropriate drainage work as part of the dcuded design,
• fafftvoirsty*1
The reservoir area is characterised by a gentle to steeply sloping topography that b dominantly covered by colluvial deposits. There exists sliding and creep movements ol soil
^tenals and rock fragments on the steeper slopes (sec Drawing IB/ES/GEO/10/02).
The repeated filling and drawdown of the reservoir may result in some localised instability, but no evidence of major landslips has been observed dunng reconnaissance work. It is recommended that at detailed design stage, and once TWL and reservoir extent arc confirmed, flial more detailed assessment of reservoir slope stability is undertaken.
Sefapicty
A preliminary seismic hazard assessment has been completed which indicates the dam is located in in area of low seismic activity (Annex D)
Based on publicly available seismic hazard assessments (lc. Midzi et al, 1999; and Band er al,
7
200 ), the Peak Ground Acceleration (PGA) values arc below 0.04g for the 475-years return penod. and about O.OSg for the 1,000-ycar return period. If the PG/\ values are extrapolated to the 3,000-year and 10,000-year return periods, approximate values arc 0.08g and 0 I Ig respectively It should be noted that this is a poor extrapolation only, and a full seismic hazard assessment is required at detailed design stage.
A separate approach has been made, based on a preliminary deterministic analysis using historical records of earthquakes in the region. This provides a very approximate PGA value of about 0.l0g.
Based on the above preliminary' assessment and ICOLD bulletin 72 guidelines, a conservative Safety Evaluation Earthquake (SEE) of between 0.1 and 0.15g should be assumed for slope stability analysis
Should the thick sequence of nver terrace deposits under the right abutment remain in situ, lhfn future design work will also need to assess the seismicallv induced liquefaction potential of '■*'»nd fine sand deposits.
onsrructroD on Shrinking and Swelling Clays (Vertisols)
Vcrtlsob soil unit presents specific geotechnical design challenges due to the high degress
of Welling and shrinkage as described below, based mainly on descripoons from ref 13 and ref
14.
To
J' ’ ksscr e”«nt, the reddish brown silt/clay residual sod displays some of the same eristics, as the clay fraction of these units can be similar to the vertisols.
lW
<Sgr
14 May-Il
137Eifapw* Sih Irwttoi nd Dm* Ptynf
The concentration of scnkmcnts on the red days rather than the vertisols probably injj both better gTound conditions for construction (e g hoW. io>ds and p
a[ n. and
condition* for nun-fed crop cultivation (e_g better drainage, les* flooding and easier tdja
|
*
Be},
Costs   for   construction   of   amah   (and   drains   and   road   /flood   embankments)   arc   minimi^ adjacent  material,  including  excavated  channel  material  is  used  to  the  form  the  embankment bunds.
Most of the main and secondary canals will be located on vertisols. Vertisols arr dark coloured
mature sods, rich in swelling days strongly bonded to humic compounds Typically they show
deep mixing by vertical movement due to clay volume change and possess large contraction
cracks ind slickensides, they arc also called "black cotton soils” (ref 14). Vertisols tend to
develop from rocks such as basalts and are typically found in the lower parts of the landscape
as a result of the concentration of base carinns in such areas which promotes (he formation md stability of smectites clay minerals (ref 15).
The engineering behaviour is dominated by the volume change exhibited by the smectite clay
minerals when subjected to changes in moisture content. When lying above thr water table,
these days show a high degrer of shrinkage on drying. When wetted they swell and heave,
exerting high pressures. When dry, vertisols are extremely hard and when wet thev become
extremely sticky Vertisols display low to moderate permcabdity, moderate to high
compressibility and low io high strength, depending on the moisture condition and soil stress
histon They may also be dispersive fref 14).
Large heave movements result when desiccated soils rich in smectites arr wetted due to  rainfall and / or irrigation.  A change in surface evaporation, such as results from creating a sealed road surface, would be sufficient tu cause such movements
Mos! heave problems occur within the upper zone of about 1  to  1.5  m below the surface I lowever,  the depth in which shanking  and iwrlling  can occur may  extend to  over 6  mm semi and regions. Typically swelling pressures up to 240 kPa may be generated (ref 14).
It is difficult to predict the heave ur settlement of these materials as it is strongly influenced by the stress history and stmt level at which the change in effective stress occurs (ref 13). 1° addition, large fissures are present tn the clay in situ that are not present in the laboratory sample, and so the amount of heave and the expansion pressures measured in the hboratoP irt liable to be overestimated. To accurately determine the behaviour of these marcnals, near full scale mils at the appropriate stress levels are re^uned. for example by the construction of embankment* (ref 13). This should be accompanied by careful settlement momtonng during and after construciion.
Iughr Structures supported in the zone of seasonal changes tn moisture content are thus susceptible io damage Heave can also cause seven: damage to mad pavements and damage to lined irrigation canab (ref 13).
I rp P4 SRlMt: f       ■ch Pjit I (1)
B0
jj-Mav-H^tcd shrink and swell behaviour of these days, has the effect of re orientating and
‘ the pbt}’ clay minerals, which results in the development of polished shear surfaces
th Io* residual shear strength. The peak shear strength (•/) of smectites is typically 15° to 2(T
Xl the rcs,dual *hCar 5UCngth (? f> tyPICaUv 5° to H° (rcf B)
fhe design of mam and secondary canals, drains, flood and road embankments and associated ffuctures therefore need to consider the following'
•      For slopes above about 2 m height, sufficiently shallow sides slopes to cuttings and embankment? to achieve an adequate factor of safety against deep seated slips through the low strength underlying vertisols.
•     Where possible, designs need to be tolerant to differential heave and settlement
•      Foundations need to be taken deep enough to limit the effects of heave Placement of of a suitably compacted non-swelling fill material beneath and behind foundations, avoiding placing foundations directly onto vertisols, is recommended
•     7o ensure all-weather serviceability, plastic clays (liquid limit greater than 70%) should be avoided immediately below the road surface, and earthen roads need to be improved bv the use of a well graded gravelly soil sub base usually at least 150 mm thick.
■ If considered necessary, such sods may be treated with lime or cement to reduce plasticity or can be replaced with better quality soils.
£* 12   Canal Embankment Earth fill Materials
The ground investigation has identified that the reddish brown sdt/day soils have a more favourable strength and swell characteristics than the vertisols. It is therefore recommend that where possible the reddish brown silt/cliy materials ire used as fill materials in preference to the vertisol unit for the main and secondary canals, and also for the major drain and flood embankments and for roads
It should be noted chat when swelling residual soils are placed as fill, their original structure is Largely destroyed and then* behave in a more conventional manner. However, their original characteristics may still have an effect (ref 14). In some expansive clay soils, the amount of heave can be significantly reduced if the soil is compacted at high moisture contents, higher than optimum moisture content Shear planes can develop at the interfaces between compacted “ytrs, particularly those with a liquid limit greater than 50%. To prevent this occurring, the two lasers need to be compacted with machinery that allows them to key into each other.
'U’thcr ground investigation and laboratory testing is required at detailed design stage to entify suitable borrow areas and to ensure optimum fill characteristics In particular, the
VlnOus Ponies of the compacted fill (including strength, compressibility and permeability) nCCd lo ** determined for detailed design, earthworks specification and compaction control
L^G
14 May-H
139fl/ >W &Ewrgy Fjh$pi4’t Njfr jmgjfj’eri Prar«^r Ppjjft*
J2U        Command Arra KocWitf Maierafc
In the Command Irrigation Area, rockfill of various sizes is likely to be required fOr (lle
fallowing uses
•       As structural fill below structures where footings arc founded on clays or behi
retaining walls To reduce pore water pressures;
•       As sub-base and road base material; and
•      As aggregate m concrete
’Hie most extensive area of rock outcrop is basalt exposures located along the alignment af i|
right bank main canal between the right bank off take weir and the town of Jawi The basalt provide suitable rockfill matcnal I iowever. the Belts Command Area is very* large and
therefore alternative sources of rodcfiD quarries will nerd to be located along the route uf the main canals based on more detailed mapping and investigation.
Both basalt and dolente should provide suitable rockfill materials, Rock outcrops have been identified throughout the command area, often in stream beds and valleys, and there will be additional localities where rock is at a generally shallow depth beneath superficial deposits In addition, die basalt escarpment to the cast will provide suitable rock fill materials Tuffs that art found interlay cred with the basalts may nor be suitable for rockfill due to the potential vanjtion tn strength of matrix and lithic fragment*, and in this case basalt is the preferred rockfill material
At the southern end ot the ennunand area arr metamorphic rocks. Some, such as quartzite should be suitable for rockfill, but ntheri, such as schist may nor br mil able due to the cleaved and foliated nature of the roclc
12.14 Cifijtl LcikAgr xorf Lining*
There is potential for relatively high secondary permeability where the canal is located on cop Dt bedrock, and canal lining along these urea* should be assumed al nutlinr design stage, to be confirmed at detailed design stage
Estimated permeability ui the sod units vary from approximately |0 * ta 10" m/s G able 10 3) The higher permeability wjiIs. colluvium, arc located al die nnnh eastern end of the project at the start of the Right Bank Main Canal and akrag the first section of die Left Bank Mafr* Canal, and * Inunjt may be required for long sections of both Mam Canal should culTusiu®1 encountered.
The clay straw have a low matcnal permeability. but where deep clacking has occurred in the vertisols unit, a high secondary permeabihn may result. Water loss through such cracks is dependent on the following:
. The mterconnecmnty of cracks, if cracks arc separated and not connected uaiet lo” will be reduced
. The aperture of the cracks, whether they are mfilled with material, and their *UiUry to heal (seal) up« in wrning.
R F4 SK04C Gccu-th Pi*t » C )
1
Hfl
]^xuy-llv* ■
. Whether the canal is maintained sufficiently wet that  ,
L
develop to begin with. 
M helled «*<> not
« Whether cracks arc of sufficient permeability water vel^« «-
5
otl sufficiently dispersive that p      ftjhw'^
lpiag
For the purposes of outline destgn, it b recommended that the main and se
condary canals a
n ot constructed from the Verttsoi unit, but from the redefrsh brown day / s
Jt  "ned
i      malcnal
from borrow areas. 
*
To limit any crack development (unlined) canals should be kept “wet’’, ic with some water i the canal prism, and that filling of rhe canals at the onset of the main irrigation (dry) seJon" should be done slowly and with care to avoid leakage and embankment breaching.
Canal maintenance where cracking  does develop should be by reworking the clays to fill m cracks, preferably with muing with more granular soils to limit fiiture shrinkage and crack development.
Hard surface (le concrete) lining of vertisols will crack and fail and is not recommended Flexible lining with geomembranes will be subject to stgnific.nt stress but will accommodate some movement of the subsoil without failure, dependmg on the quality and properties of the geomembranc. However unprotected gcomembranes will not last many years being vulnerable to sunlight, livestock and persons entenng rhe pnsrn, theft and coarse bed sediment.
14-May II
141p,vta
CONCLUSIONS AND RECOMMENDATIONS
13  c^dggioas ' G<°'Ogy *nd Geo,echnicg
&         Hrt5>biliry level ge..technical investigations combmed wuh a renew of prevrous wnrk amj reconnaissance geological mapping has been completed There are no previous site
.nvestig.no'” found for these localities. The following geolog,- i, .denufied m the project area
. The dam site and reservoir area bedrock generally comprises Tertiary age interlayered moderately strong lithic and agglomerauc tuff and strong aphanatic basalt, with some dolcritc intrusions;
. There is some unresolved variability in these units along the dam iris with potential for the presence of faulting through the dam site. The left abutment predominantly comprises tuff overlying basalt, tn the centre of the dam site valley tuff is found to a depth of 50m and hasalt is absent, whilst on the right abutment the bedrock appears to compose basalt, and luff has not yet hern found;
•     The tuff generally has low permeability but both the strength and permeability is vanablc dur to: (i) differential weathering (that is not related to depth); (ii) differing composition / layering within the tuff; and fin) closely jointed zones;
•     No faults have been positively identified but geophysical data combined with photo hneimcnt assessment indicate potential for feature orientated SW- NE. along the nver valley and perpendicular to the dam axis;
•     Superficial deposits comprise cohesive and granular alluvium in the nver valley, and colluvium and nver terrace deposits on the abutments Superficial units are thin on the left abutment but very thick on the right abutment (10m at the top of slope, more than 30m on the lower half of the slope;
•     In the Irrigation Command Area bedrock composed Ternary basalt and dolentc under most of the area with Precambrian basement metamorphic rocks (schist and quartzite at the southern end of the Command Area; and
•     The Command Area is predominantly covered tn high plasticity swelling vertisols with reddish brown silty clay forming slightly higher ground; there is also often a well developed wrathenng profile of highly and completely weathered basalt residual sods recovered as vanable gravelly clays.
An estimation of the geotechnical parameters and characteristics of each soil and rock unit has ^cn made to support die feasibility stage designs. The key findings are.
*     A rockfill dam with an asphaltic core is appropriate, using basalt rocknll taken from hilltop quarry' sites located about 2 to 3km from the dam site,
The basalt is a much more suitable rockfill material than the tufi,
•     Reliable sources of suitable days, sand and gravel are not available in the dam site area lnd  wdl need to be imported from outside of the area or produced from crushed
basalt;
Alluvial and colluvial clays beneath the dam footprint will need to be removed;
’ For higher dam Options A to C. it is assumed that the thkk deposit of granular terrace ^d and gravel beneath the nght abutment will also need to be removed due to the Potential for liquefaction;
Pin l i)
14 May 11
(
143JvifrnA1
Afrarity a^lFdrn’ £uEw^
Efhofu-ir A'r/f /nqpMfl antiDrwup Pnwtf
Tuff  and  basalt  bedrock  beneath  the  dam,  together  with  any  fault  zones  Dr
dolcrite
dykes intersected is likely to require grout injection treatment to reduce the permeability and leakage potential
Buried   features   idendbed   by   the   boreholes   and   geophysical   survey   beneath Mam axis   require  investigating  at  detailed  design  stage  and  may  require  addition,|
and replacement,
Where the Main canals cross rock canal lining  should be provided to
leakage;
The Main canals cross colluvial soils and vertisols On vertisols, if these are not
“ Clv»Hon
prevent ex<CSRr f
.
remov ed (sec below), the canal design needs to accommodate lower strength sods u'th
high swelling and shrinkage potential and the presence of shrinkage cracks,
Where possible, vertisols should not be used for main or 5econdary canal embankment
fill, paruculariy if concrete lining is proposed, due to swelling-slinnkage characteristics
and potential difficulties in working and compacting die material I he Vertisol material should be removed and replaced with suitable (loamy) earthen material;
The proposed all-weather roads should be designed with a granular earthen sub-base
beneath the aggregate / gravel road tnatcual raising the road above- natural ground
level.
As the vertisols arc highly susceptible to heave and can have low shear strcnglh, high compressibility and be highly dispersive, structure foundations and retaining walls for
major structure; need to be taken deep enough and to be adequately designed to
overcome potential heave, bearing capacity failure. large seiilemrnts and sliding For
the ^mallri irrigation and drainage structures it will most likely be cost effective to
remove the vertisols and import suitable earthen material and provide shallower
ioundatons
.All  of  Lhc  above  conclusions  arc  appropriate  for  feasibility  stage  drsign,  and  mav  be  reviewed and confirmed by more detailed geotechnical ground investigation at drilled design *tsgc
U.2 Conc/usions -
“rhe project area, including the dam site, reservoir and irrigation command area, is cbaiactcn^" - bv differ cm hydrogen logical units. These uc over deposits; alluvium; colluvium / rcsidiud reworked deposits, basali. dokrite dykes and basement rock units The major aquifer units m
rhe nea ate associated with the unconsolidated to loosely consolidated river deposing and the fractured and weathered basaltic ruck units.
There are few drilled deep rubewclh in the area, and the major unproved poiabk* water suppb sources arc open wells and shallow bored wells serving individual homesteads, and proLCci^d springs. Scram* and unprotected springs remain the major source of potable water for abol|f half the prjpulariotL
1
Dau for existing drilled rubeweik me for the most pan not available, and were only lour’d f*?r four wells drilled in the upsirram part of the command area. The data available for these (bur rubewclh are: (h the lubewrll Ing; (ii) well depth, (iii) SWT; and (jy’ estimated yield-
L p J 4            - C            rm i I v
144
H .Mav 11fers tn lhe PrO|CCt haVC fn<xicra'c ,O low productivity. Yield* of aquifers ire in the
A<,lU f I 5 l/s
order o>
f°r 20 m drauxlown, but are very variable
groundwater quality as determined from analysis of water samples from three utils in the ( Ormand Area is generally within the allowable limits set by the WHO and Ethiopian
primes for po!.bku*atcr
gised on existing and projected rural and urban populations the demand for water based on 15 I yj per capita for the rural population and 25 1 /d per capita for the urban population is 2.78
1
Mm’ (2010) and expected to increase to 4 16 Mm  (2030). This is equivalent to a 24/7 flow of 0.W rn’/s and o 13 m’/s respectively.
Groundwater flow from the protect area is likely to approximate at least the baseflow (i.e. April monthly low flow) of 1.4 m’/s measured in the Main (Enat) Beks river at the bridge near the southern boundary of the project area, lhe total groundwater resource may however be significantly more than this The projected potable water supply demand of O.Bm’/s is about
y»of the baseflow.
In theory the protected potable water supply (and sugar factory) demand could lx- met by sinking productive tubrwells though out rhe projeer area However this faces rhe following uncertainties / problems:
•     The extent of productive aquifer (ie, presence of w-eathcred and fractured basaltic rocks and unconsolidated sediments / river and stream deposits ). which would
support yielding boreholes remains uncertain and can only be determined by additional survey including test well drilling in the project command area;
•     Demand by the rural population ls scattered in small settlements and isolated homesteads, and
•     Demand by the urban population is concentrated in the main Worcda settlements, including \X’erk Mcda, Fendika and Pawi
l<> meet future potable water supply demand, including water requirements of the sugar factor, 2 lnu potable water supply solutions is required to replace the current widespread use of
streams and unprotected spnngs and shallow* wells. The mix is likely to include:
Reasonably sized potable water supply systems for the major urban areas as well as for ihc sugar factory’, wbcrebv water is diverted from streams / rivers flows, treated and P’pcd to the point of use with intermediate storage as required As a proportion of the flow required for irrigation any surface water diverted for factory / potable water lu Pply use will be negligible (<1%) Specifically it is envisaged chat the sugar factory
divert and treat waler from the Main (Enat) Beks river upstream of the proposed factory location;
Boreholes 20-60 m deep of various sizes with (hand) pumps serving single homesteads ° r dua<en of homesteads depending on well yield The larger boreholes may even have
e   4 5lmpk distribution system; and
rf
*   Hected spnngs and protected shallow wells up to about 15 m deep mostly serving 5In &le homesteads
Gci «<th
145
14- May-11Dyomin. 
»/ fifhtpia.             of U^rr Ettrp
EffifopM Stir              aod Dnsoo^t PrvpJ
The project area is characterized by shallow ground water generally found at depth,  f 5 
o       4l |
with the shallower depths largely founded in topographic lows, i_e. the plains. During the "
season much of the lower lying arras, largely vermols, become waterlogged.
With the irrigation project canal seepage and application losses would increase infil^t^
recharge to the groundwater aquifer possibly as much as 150-200%. A greater increase 1$ v
unlikely given the semi-impervious nature of the soils and underlying marginal aquifers.
The groundwater resource,  as roughly  indicated by  the with-project baseflow f rom die project area  of (say) 2-3  m'/s,  is not significant compared to  the average dry  season irrigation demand of 60 m'/s being diverted from the Main (F.nat) Beies nver.
Irrigation during the dry srason for double cropping and / or to enable sugarcane cropping, ui£ potentially seriously aggravate the waler logging problem as there is limited natural verticil drainage and low hydraulic gradients over most of the command area.
( .arcful water management to avoid over-irrigation, and provision of surface drainage to improve runoff of surplus water following rainfall, is therefore necessary to avoid water logging
/J.J Recommendation*
Further geotechnical ground tnvcstiganons are recommended for detailed design. These arc summarised in Table 13-1 below
Table 13-1: Recommended Specific Issues to be addressed by ground investigation for Dei ailed Design
Design Element
Objective*
Potential Scope of Invcstigatiooa
Dam Snr
Increased definition of bedruck pro tile at abutments and anomalies identified by drXtng and grophysics, in particular:
1)     thick tcrncc deposits an right
abutment.
2)     boundaries l<twren tuff and
basalt;
3)     potential Units / vertical features identified by
^cophvxici
Additional deep Ijorcholrs along  dam iais as well as upstream and downstream rn< dam axis
Downhole gcuphysical logging. Seismic geophysical survey
Dam Sire
L —-------------
__________
Dam Site
De tailed sampling and testing of granular teaice deposits
Careful  dulling  to  avojd  washout  of  finC additional Sl’Ts and tailing head te^—-
( or.firm / improve permeability values determined from laigeon tests in Tuff
and Basalt
Additional   Lageon   tests   tn   borehole*   ini targci fractured areas / faults
Dim Sire and
| Spillway____ _________
Improved water level morutonng al _ abutments
Additional piezometers and rnofuturmg
L tp F4 SRMC Gc<*c<h Part 1 V
146
14 May 11.✓&**>* «<IF‘rf'rd’£w®
Objectives
Potential Scope of Investigation*
Improved    definition    of    bedrock    profile and overlying soils
Additional boreholes along ipillwiv route and east side of saddle.
geotechnical    parameters,    in    particular classification and strength
Rockfill Quarry Sites
Improved reserve estimation and definition of liasalr rockfill parameters.
Reservoir Area
More   detailed   assessment   of   reservoir slope stability and leakage potential (after
T\VL confirmed! ________ __________________
More standard classification testing plus specialist laboratory testing for (i) UCfi and point load tests; (u) Cl’ rmial tests for effective shear strength tn clan; fui) compaction of terrace gravels; and (iv) dispersion in clays 'spillway area)____________ Boreholes, surface samples, tnal pits (nppabditv Inals)
.More detailed engineering geological mapping of reserve.
More rock strength and durabibrv aggregate resting_______
Detailed  remiKc  sensing  followed  by exiensivc geotechnical walkover
Main canal*
Canal embankment
rruterik
Further assessment once alignment and mapor structure locations are confirmed of, as appropriate, case of excavation, canal stability on side slopes, fill materials and shrink swell characteristics of founding strata. 
Determine suitability of sods materials for use as embankment fill to rhe mam and secondary canals, and elsewhere. In particular, seasonal pcrmeabdiry f formation of deep cracks in the shanking and swelling clan.
More detailed engineering geology mapping along con tinned main canal alignments. Additional tnal pus and soils testing. Construction and testing of tnal section(s) of canal
Tnal pits at borrow pits / tourers of fill along main and secondary canals. Laboratory tests such as index rests, compaction combined with permeability and wetting and drying, and mineralogy, swelling, erosive and dispersion tests. Use of chemical agents for tests on lateritic
soils.
Construction of tnal lengths of embankments :o rest material performance is also recommended, and also lining (geomembrane / geotextile/ concrete)
pdoos _ ______  ___  ___ ____ ___
(r *fttund  Area ^tion, for
^•tnicturw
Assess / confirm shear strength, bearing capacity, settlement, and shrinking / swelling specific to sensitive or large
structures
Tnal pits.
Soils laboratory toting a« above including shear strength and conioUdalion.
14-May II
147Ftdfrj; OrmoiTuftt RrtM; rEttutie. Mwtn r U jftr & Entry
Elbuput NlJt                  Drainjp Prwrrf
At detailed design stage a full seismic hazard tn accordance with the recommend ICOLD bulletin 72 should be undertaken, particularly for if a large darn is proposed*” reservoir volume and operating conditions are confirmed
Once detailed ground investigations arc completed, the following actions arc reconim^ )f be completed at detailed design stage to refine the slope stability assessment and dam des^
• Refine the soil profiles beneath the dam and spillway, and particularly the thidu>eS5
’ On<e d*
variation of the alluvial clay at the spillway and river terrace gravels beneath the nght abutment;
•      Optimise method of construction on thick superficial deposits (treat, remove and
replace or realign dam);
•      Optimise the design geometry of the rockfill shoulders to account for improved rodfil parameters, vanauon in slope elevation, and soil thickness and van ability across the valley, and
•      Use the accelerations derived from a more detailed seismic hazard assessment completed in accordance with ICOIX) ”2 recommendation*
\X*hile the groundwater resource is not significant compared to the surface water resource it cm usefully be used to improve potable water supply to both rural and urban populations
To determine the extent of the (marginal) aquifer further detail study using test well (borehole drilling^ is recommended tn the Command Area A more detailed assessment will then be possible of die cost effective use of borehole sourced groundwater for potable waler supply and potential for limited irrigation supply.
UB H SRO4< Gcc»«ch I'arr • (1>
14M
14-AUv HREFERENCES
14
-jgjfcnInstitute of Geological Surveys (RIGS), 1996. Geological Map of EthiopuTz^EditK^
I
, n 000 00° 5Clle’______ -—------------------------------------------------------ ------------------------------ ------ 1998, Hydrogeological Map of Ethiopia, 1:2,000,000 scale,
ElG5« ’     '__  —_----------------------------------------------------- -- ---------- -  ---------------- --- ElGS 1999 R’tPbnilt,on of GeoloPcil1 MaP of Ethiopia, 2nd Edition
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>ia
J
Tb( F0M, 1997 / 1998 / 1999. Abbav River Basin Integrated Development MasteTpian Protect Phase 1 Reconnaissance, Section II - Sectoral Studies, \ olumc II - Water Resources. Part ’,
And  Reservoirs,  Geology.  Geotechnics,  Field  Investigations.
[JlfD- •**
b) Phase 1 Reconnaissance, Section III Vol. I Natural Resources Part 1, Geology & mineral Sources. VoL II Water Resources Parr 3 I lydrogeology
[ (j phase 2 Data Collection and Site Investigation Survey and Analysis: Section 1 - Main Report, Summary Development Strategics and Scenarios. Section II Sectoral Studies, Volume I - Natural Resources. Pan I: Geology, Morpho-lithoiogic and Morpho-structural 1:250,000 maps VoL VI Uircr Resources Development Part 3 Hydrogeology.
6   SMEC International Pty Ltd. 2008. Hydrological Study of the Tana Bdes Sub Basins. Main Report
?
BSI3~ 1975. Methods of test for soils for civil engineering purposes. British Standards Institute Note, has been superseded by 1990 edition). 
3
t BS593O 1999 Code of practice for site investigations British Standards Institute.
BS8HO2: 1994 Code of practice for earth retaining structures. British Standards Institute. HO Tomlinion, MJ. 1987. Pile Design and Construction Practice, 3rd Ed. Palladun Publications Ltd.
Craig, R.F., 199", Soil Mechanics, 6th Ed. E & FN Spon
• Tomlinson. M.J., 1995, Foundation Design and Construction, 6* Edition, I.ongtnan
0 Neill, MW' & Poormoaycd, N., 1980. Methodology for Foundations on Expansive Clays, Proc. ^CE, Journal ofGcotcduiical Engineering, 106. GT 12, pp. 1345-1367.
14
F°ok« P. G (ed.), 1997. Tropical Residual Soils. Geological Society Professional Handbooks
G 5f2P?lSoacty London^
r
____ __________ ______________________________________
Rfev” G M e» >1 (ed.) 2006, Clay Ma tends Used in Construction Geological Society, Undon, S P£“1 Publication 21. 
-„ *' ~               ^P00*! Digest 1 Concrete in Aggressive Ground, 3* Edition.
y—.  ^
n
on  R. 1988. Field Hydrogeology. Geol Soc of I-ondon Handbook Series. OL press.
115
^Qnental consults. Ethiopian Guideline Specification for drinking water quality, Addis Ababa,
! ° K«-A^taT“~-------------------------------- -- ------------------------------ 7----- 7-----------------------
I
tri8gahKoo, Wat         Ju, \X aterc pr powowere an r and Wat     d Watere Rr Rese. Es. Enngiginneeereirning, 2002     g, 2002
tT1
at
S p f '       ~ ~——■
j(  -T”?GrOu,ld water andWa  tu(cbre an wedl tlsu, tbhe wirde cllsd, tioon hir, 199’      d edition, 199”
~~ "- H}B59/9g/j Ground water flow geohydrology IME Delft the Netherlands
1,1 Hr,,
* r
Part 1 
14 May-II
(])
149Fftfa; lifaf&nfrr
Mimity •■''ETjflrr
fr/Aw/fcW jVZ‘> Jn^pfiwr murf /)i'3jragr‘ iP^TW^K'**** -^'0
\ii /’’’?*”
ANNEXES
XS\/WlTH MAIN REPORT)
pARTJytJ^
| ANNg^
,aNNEX?
ANNEX C=
prOIECTAREA PHOTOGRAPHS
C_ 
COMMAND AREA GEOTECHNICAL PARAMETER PLOTS
da m site GEOLOGICAL MAPPING OLTCROP AND JOINT
OBSERVATION POINTS
asM-xD -
PRELIMINARY SEISMIC HAZARD ASSESSMENT
part 2 OF 3
annexe
dam site drilling investigation final factual REPORT, ADDIS geosystems CO LTD J ANGARY 2011
aNNEXF-
\SNEX G:
 . 
DAM SITE GEOPIIYSICAL SURVEY FINAL REPORT. JANUARY 2011
DAM SITE SLAKE DURABILITY PHOTOGRAPHS
ANNEX H I:
TRIAL PIT LOGS DAM SITE AREA
[ANNEX HI
TRIAL PIT PHOTOGRAPHS DAM SITE AREA
I ANNEX HJ
I AB TEST RESULTS FROM DAM SITE TRIAL PITS
PART 3 OF 3
ANNEX I:
RIGHT BANK MAIN CANAL DRILLING INVESTIGATION FACTUAL REPORT ADDIS GEOSYSTEMS CO. LTD, DECEMBER 2009
ANNEX J;
RIGHT BANK WEIR GEOPHYSICAL SURVEY REPORT
ANNEX KJ:
TRIAL PIT AND HAND AUGER LOGS: COMMAND AREA
.ANNEX K2
TRIAL PIT AND I LAND AUGER PHOTOGRAPHS: COMMAND .AREA
ANNEX LI
IAB TEST RESULTS FROM TRLAL PITS: STAGE 1 COMMAND AREA
.ANNEX I..2-
1 AB TEST RESULTS FROM TRIAL PITS: STAGE 3 COMMAND AREA
ANNEX L.3:
IAB TEST RESULTS FROM TRIAL PITS STAGE 4 & 5 COMMAND ARFA
ANNEXE
SOIL HYDRA UIJC CONDI ACTIVITY MEASUREMENTS
axnexn
GROUNDWATER QUALITY TEST RESULTS
AXN EXO:
PREVIOUS GR( 3UNDWATER WF.IX Cl )MPI.E DON REPORTS
i. I GUIDELINES FOR TESTING AND MONITORING GROUNDWATER WEI.1SFfdtrui Dawnfu                  fLrfrcpw. Afw/fn ^Fi/rr jw/ E*T EjLwpwi NiJr I          axd Dnruqgf Prytrfproject aheaFcdtrd Drjvayu/).                Elhupta. Mtwfn of VFafer & Ewjp Errvcpiai \t/t Irritate* a*d Dump PtyrrtPlate 2 Blocks nt tuft at clam site left abutment centering at LTM 2611 81* & 12935'MN
K«c3 Blocks of Tuff at the dam site left iDutmrnr
Plate 4 Massive Tuff at the dam site left abutment at UTM26I226E& I293625N
atf-r-x 
site found
Plate 6 CnJoaduig drilling ng
f 264053E^ 1292517NPlate  7:  Dismantling  drilling  ng  pari*  for
Plarc 8; Transporting drillrng ng parts
irmsp< >rting using labour
Plate 9 Camp setting for drilling at drilling site
Plate 10. Pu raping water from Mam Bek* Riw* *'
I
ilnUing
Plate    J    I:    Drilling    il    UBDHllefi    bank    central
PJair 12. Falling head rest LIU >112
river valleyPlate t5i Agglomeratic / lithic ruff forming low rxmded hdls (probable basalt ndgc at higher dm&in m background) View westward from *.am Nte
area, left side of gorge
pt,,. IS: B..JI fc-nwg >«p
* mf!
nonh.
“'“b"'Plate 19; Tuff outcrop above rcscivoit area
Flair 22 Dolentc dru Dam Site
side of gnrjv
Place   21   Ba*ah   sill   with   palcosoil   above   cuff, reservoir area
Place 25 Smoothed hills likely to indicate residual soils and colluvium overh uig ruff Dam sue left abutment view looking upstream
side above dam sitePlate 26 Channel alluvium (sand and gravel) Reservoir Area, view looking upstream
Plate 28 Reservoir
Area right side
slope: probably
river ten ace
deposits on the
side slope
overlying luff
bedrock
gorge entrance.
Plate 30: Dam Site gorge entrance right sidePlate  31:  Dim  Site  nver  channel  view  looking down^tieam.
Plaie 32 Dim Site right abutment new from kft,
'' f'**" ’W/n »/ ff jrer
-. ,^/uf A'* .’”?( ** ^arju^r Pn/nt
u
annex b
COMMAND AREA
otechnical PARAMETER plotsFtdrr*/ Dmntfr/ RrjwWr of E/hupi*. Mtnutr, ofW^tr <5f Ejmji
iutapu*
oW Di’orMp PreferDopIN (m bolow ground lovol)
Figure A1: Moisture content against depth
v ®nisols ■ RedBrown SillClay A Yeilow/Grey SilVCIay ♦ Weathered Bedrock
S'i fl IC
CF t ►
*   “ V> >
w
IGIROI ConsurtarFigure A2: Plasticity chartpoplh (m bolaw ground lavol)
figure
A3; Effective angle of shearing resistance against depth
c oo
1.00
2.00
300
4 00
A
■
5 00
5.00
700
0 00
Ooo
’Doo
10
15
20 25
PM' (dogrees)
30
r, Voffisols ■ RedBrown Sllt/Cla^ * Yellow.G'ey S*®W
---------- 1
Halcrow
GMT
•'•fl™*1Figure A4: Particle size distribution curveDepth (m below ground level)Dnplh (m ook»w ground ksvol)Dry D®nsity (Mg/m3)Dry Density
Figure A8a: Compaction Curves
l
10% Air Voids '• 0% Air Voids
\'\
\     5% Air Voids \
••
i-----------------------------
20                       25 Moisture Content (%)
Vertisols
x MOD OMC
Kalcrow
Gar<rai»or -ir^ralnd Purs IGIROJ Consular
o-rDry Density (Mg/m3)
Figure A8b: Compaction CurvesSlioni Straw* (kN/rn')
250
k*
✓ *
✓
»
IX-     ✓✓
s
X ,<•
<< I
X
X
50
- —    —---------------- T
100
150
Normal Stress (kN/m )
2
■ TPB34, 1.2m
■ TPB32,1.4m
}',aic°^Depth (m below ground level)
Figure AW: Undrained shear strength against depth
o
■ o 00
o
0
1.0
o©               ■ G
0
O
n o 13 CM
C
■
15
©
2.0
O
2.5 -
■0
©
O
3.0 I 0
~i
20                  40               60                80               100              120 Peak Undrarned Shear Strength (kN/m J
140
z
o Vertisols
■ Red,-Brown Silt/Clay
A Yellow Grey Silt/Ciay
k
HalcrowDeph (m below ground level)
Figure A12: Coefficient of consolidation (c )
v
against depth
5Figure A13: Permeability against depthDepth (m below ground level)
Figure A14: Organic Matter Content against depth
0.00
▲
■
0 50 -|
o
o
1.00
e
o
x
2 00 •
■e
0
A
2.50 J
3 00 -
3 50 •
Organic Matter Content (%)
■ ReaBrown Sift Clay A Yellow/Grey SllVClay X Weathered BedroC*
'laicrowFigure A15: Sulphate Content against depth
o
1.50-
%
I
3.00 J
<00
0.00
T
0.05                    0.10                    0.15                   0.20 Sulphate Content (%)
0.25                   030
■ Red/Brown Silt/Clay
AYetlow/Grey Silt/Clay
Halcrow
Genaraton Inf^yatad Rural
Ja.iotywt i GIRO I Cc^tuiumtsDepth (m below ground level)
Figure A16: pH against depth
c Vertisols
■ Red/Brown Silt/Clay
'Salerow
G«wfi>‘crFigure Al7: Mass loss on ignition against depthEuM                  R/pMrd Ethitpw. Mwitr. fTgrr u*i Earrp Elhtifw Ni/e Imgariofi wd Droit off PnfetTlznrr^,
ANNEX C
PAM SITE geological mapping outcrop and joint observation pointsFrier* Dwrtf. Rrprii. FatofM, Nniary oflf'^tr & Effg l-fagw Xri               airi Dnai^ge ProfitUpper Bdes Oam Station
Site Geological Mapping: Outcrop Observation Points
Specific location (IJTM)
Formation
Easting
Northing
261304
1293787
Dolcrilc
261191
1293577
Tuff
261923
1295694
Tuff
261923
1295694
Tuff
264931
1299615
Aphanatic Basalt
261994
129579!
Aphanatic Basalt
I---T
--------- 9
10
261672
1294463
1294206
Tuff
261773
1294707
Tuff
261725
1294449
Tuff
261724
1294387
Tuff
261677
1294207
Tuff
261555
1294071
Tuff
261290
1293619
Tuff
261251
1293645
Tuff
261168
1293612
Tuff
261168
1293612
Tuff
260641
1294240
Aphanatic Basalt
19
20
260306
260332
1294213
1294279
Aphanatic Basalt
Aphanatic Basalt
260186
260131
260035
259938
259914
259899
1294441
1294453
1294531
1294628
729474?
1294741
1295528
1293974
1292166
1292477
1293455
1293438
1293436
1293426
Aphanatic Basalt
Aphanatic Basalt
Aphanatic Basalt
Tuff"
Aphanatic Basalt
Aphanatic Basalt
Aphanatic Basalt
Aphanatic Basalt
Aphanatic Basalt
Aphanatic Basalt
Aphanatic Basalt
Aphanatic Basalt
Aphanatic Basalt
Aphanatic BasaltSpecific location (I'TM)
Station          _
Easting
Northing
formation
1
35
262356
1293604
Tuff                ——
-
36
262200
1293686
Tuff            —"—
37
261901
1293864
Tuff ’                   ------
38
261612
1293746
~Tuff               ------ -------- —_
39
261549
1293778
Tuff                 —-- -------
40
261292
1293632
Tuff “                                —.
41
—
261228
1293581
Tuff                            *--------1
42
261245
1293637
Tuff                               —'|
43
264053
1292517
Aphanatic Basalt
44
261013
1292957
f’Tuff
1
45
261118
1292805
Tuff
'
46
261128
1292802
Tuff
47
261083
1293094
Tuff
]
48
261226
1293625
Tuff
49
261215
1293623
Tuff
50
261185
1293597
r Tuff
51
261178
1293571
Tuff
52
261177
1293534
Tuff
53
261144
1293526
Tuff
-
54
261102
1293443
Tuff
—*
55
261105
1293361
Tuff
56
261075
1293277
Tuff
57
261086
1293492
Tuff
58
260687
1292187
Aphanatic Basalt
59
260730
1292161
Aphanatic Basalt
60
260745
1292133
Aphanatic Basalt
61
261151
1293544
Tuff
62
261189
1293599
Tuff
63
261196
1293605
Tuff
64
261203
1293602
Tuff
-------- '65
261229
1293606~~
Tuff
J
66
261216
______
1293606
Tuff
261209
1293625
Tuff
H’!>.«. SHe
«<■ Orientation .f WnB
Dip (
deg)
Dir.
Persistencv
(m)
APP
(cm)
Infill
Roughness
Spacing
(m)
220
320
0.5
6
3
8
0.45
0.6
Set I
60
85
0.8
2
Clay
Rough und
Set 2
0.4_______
[Tight
Rough und
0.3
0.21
T^IllS I 129
3623
i
Set I
90
Set 2
60
150 220
90
110
c|av
0.45
0.50
1293574
Set 1
90
130
146
Clay 
clay
Rough und
Set 2
Rough und
1293534
Set I
Clay
Clay
Clay 
clay
Rough plr
Set 2
Rough und
Set I
Rough und
Set 2
Rough und
1
3
0.32
2
261144
1293526
Set 1
Rough plr
Set 2
Clay
clay
Rough und
1293443
0.32
2
Set 1
110
Set 2
Rough und
75
85
85
220     >10
Set 1
Rough und
280     >10
Set 2
Rough und
1293361
Rough und
Set I
Set 2
' Rough plr
Set 1
J Set 2
270
330
270
270
Clay
Clay
Clay 
day
Clay
Clay
Clay 
clay
Rough und
Rough und
Rough und
0.10
1.5
1
0.4
0.14
0.85
0.85
0.21
Set 1
Set 2^
290
75
85
Clay 
clay
Clay 
clay
Rough plr
1293492
Rough und
Setl
Set2
150
220
Rough  plr
>293544
Rough plr
Set |
190
300
Clay
I Rough plr
Rough und
320
Clay
clay
Rough und
Rough undID
location
_ UTM
E
Dip (deg)
Persistency^ App.
Infill
((mnt))
(cm)
R °ughne
N
Amt    Dir.
13    261196     1293605
Set 1
Set 2
85
85
180
210
1.10
1.00
8
8
Clay 
cla\
R °ugh und
14    261229     1293606 Set 1 Set 2 Sei 1
80
80
80
210
322
30
Set2_         70        100 15    261216     1293606
Undulating
Undulating
Undulating
Rough und
Set I Sei 2
16     261209 ’ 1293625 Set 1
85 ^85,
200
200
clay Clay     ' clav
T
Rough   und Rough und
I 70        300
- Sct2 j 87 J 178_________________
Deg. = Degree, App. = Aperture: Und.t Undulating; Plr = Pla,mr
Rough plr
^Roughplr 0.5.       /a*** y
ANNEX D
PRELIMINARY SEISMIC HAZARD ASSESSMENTFwimi/            fapMt of Eihupta, Mnutrjr of Wattr d” Ewj; ExMpuv jXiir /rnguM and Ontm^t PnptrfUpper Beles and Negeso Dam Sites
preliminary Seismic Hazard Assessment Report
February 2011
The report is intended to be a preliminary study to provide backurnim^ r Detailed seismic hazard assessment in accordance with ICONi! T. 'nf°rmat,on
required should dam design advance to detailed deZnsLe X*,, on .he dan, height. volume and
^7 7" **
population and it is therefore not appropriate to undertake this analysis at r. stage, when options for dam requirements are still to be finalised Y f b y
The report identifies that both the Upper Beles and                  n c-
™ disimce away .be eptcen^
fXsX'X^
seismic activity. The dam site areas arc termed asekm.r 4 formulae have been used to determine the seismicity at the daZZ.
h rcuorded
The report recommends adopting a peak ground acceleration (PGA) of 0.10g for dam design, although the methods adopted are not in accordance with ICOLD guidance
and should be reviewed for detailed design.
A separate check has therefore been made using published seismic hazard assessments (Midzi cl al. 1999 and Band et al. 2007) and the conclusions for likely peak ground accelerations (PGA) found to be broadly similar. Using these alternative sources of information, the PGA values arc similar for both sites, and are below 0.04g for the
475 years return period, and about 0.05g for the 1.000-year return period. PGA values extrapolated at the 3,000-year and 10.000-year return periods are 0 08g and 0.1 lg res pcctively. however, it is important to recognise that this is an approximation only.
References
Banel et al (2007): Hom of Africa Natural Hazard Probability and Risk Analysis. Humanitarian Information Unit. US Dept of Stale. June 2007.
Annri^n   rf   Seismic   Hazard   Assessment   in   Easiem   and   Soulhem   Africa. "*''("<W,sc .Vol.42No 6 December 1999.
aSeismic Hazard Assessment of the Dam Sites at Nepe« Beles in Eastern Ethiopia 
1.        Summary of Results
1.1       Tectonic regimes
1.2       Seismicity
1.3       Saturation magnitudes
0
‘  ^pper
1.4       Conservatives values of expected ground accelerations at the dam sites  f
o
Negeso and Upper Beles—deterministic approach
1.5      Return periods
1.6      Maximum Credible Earthquake MCE
1.7       Resonance/rcverbcration/liqucfaclion effects
1.8       Induced seismicity
2.          Introduction
3.          Regional Tectonic Activities
4.          Regional Seismicity
5.          Frequency of Occurrence- Magnitude Relation
6.          Concept to Estimate Maximum Ground Accelerations
7.          Macro Seismic Observations and Intensities
8.          Engineering Implications
8 1              Ground accelerations from instrumentally recorded earthquakes
8.2       Ground accelerations from macro seismic observations
8.3        Conservative estimate of ground accelerations at the dam sites of Ncgcso and Upper Beles
8.4        Recurrence periods
9.          Ground Vibrations, Liquefaction   and          Resonance
10.       Recommendations for Specific Geotechnical Site Investigations
11.       References
12.      Figures
Appendix 1
Appendix 2
Appendix 3
Appendix  4
Appendix 5
Instrumentally Recorded Earthquakes in Central and Western Ethiopia/ Southeastern Sudan 1973- 2005
Historical Earthquakes in Central and Eastern Ethiopia/ Sudan Magnitudes M >6.2 and/ or Intensities I > VU1
The Earthquake Tremors of |2
Region
February 1845 in the Lake Tana
The Seismic Crisis of 1906 in the Shoa Province The Seismic Crisis in WoUo 1961SununaO <>f Resu,ts
u.h<.aim<’fasscssingthc: *’jK^d Upper Beles (N
and adjacent parts of the
regimes.
seismic hazard ar the dam sites of Negcso ( N 8 858° E 11.694°. E 36.807°) the seismic activity of the project region is accumulated and fit into the existing tectonic
though the dam sites arc geographically separated by 315 km (straight N-S
EvCn  on) we find that any seismic hazard at the two sites can be regarded the same.
dirCC' due to the fact that both sites are part of a vast iotra-plate area of a semi-solid
™ lSwherc seismic energy release is practically non-existent at a radius of about 200
<hesi.es.
We therefore conclude that the seismicity conditions at Negcso and Upper Beles arc same jpd, under the assumption of similar geological site conditions, that any 
Ssmic hazard can be treated alike for both sites.
1.1  Tectonic regimes
South-eastern Sudan: the northern extremity of the Western Branch of the African
Rift Valley, dominated by lateral E-W trending extension at a rale of about 8
mm/ycar.
Central Ethiopia -Afar- Red Sea. Main Ethiopian Rift and its extension into Afar and the Red Sea. Also this region is tectonically dominated by lateral E-W extension.
Easiem Ethiopia - Western Plateau: including the areas of Negeso and Upper Beles dam sites, constituting a vast inlra-plate region, which is relatively stable. Any impact
of seismic energy release at the dam sites would be attributed to destructive, distant, shocks along the well know n rifling segments of the African Rift (see above).
12 Seismicity
In all, a total of 255 earthquakes are accumulated within a grid 4° - 16° N and 32° - 42 E. covering the time period of 1973 - 2005 (instrumentally recorded data) and historical data from 1630- 1977.
“ismic energy release pattern in the three different tectonic sections mentioned
a °ovc is directly obvious from Fig.l. which includes the instrumentally recorded data
lA PPendix 1) for the time period 1973- 2005, i.c. 33 years. This data set includes 240
ev ents.
balHA  ^  earthcIuakes   from    the  16th    century  (Appendix  2)  are  summarized  tn  Fig.3. jjp inc|yj^trUctive* magnitudes M larger than 6.2 and of intensities I larger than IX,
k'ween the rift systems, the Western Plateau, reveals a typical intra-plate
from  *
e
lav ’or- No seismic events are found within distances of about 200 km
" e Project sites.
313 Saturation magnitudes
Southern Sudan: Largest earthquake expected (conservatively largest pos |,|
Main Ethiopian Rift- Afar: Largest possible earthquake expected M = 7 q
Intra plate region: Even though we have no direct reports if seismic aelivit
assume the occurrence of minor events, which cannot be detected by natio^ 7* seismograph station networks or felt by local people. The nature of these ant
minor events could be explained by intra-platc stresses, which arc released*1 IClpalc<1 geological weaknesses. Magnitudes of these anticipated events would have "
magnitudes smaller than 2.5. which would not provide any hazard for construction
sites.
1.4 Return periods
Considering the whole grid of investigation, we expect a frequency of occurrence of medium-size earthquakes in the magnitude range of M = 5.7- 6.0 is about 9 events in 33 years, i.c. one event even* A years. For larger events, magnitude range 6 I - 6.4, we consider 4 events per 33 years, i.c. one event every 9 years
The occurrence of destructive earthquakes of magnitudes larger than 6.3 and / or intensities larger than Vlll. might be very roughly averaged from the data of
Appendix 2: 16 events in the time window of about 370 years, i.c. order of about one event per 23 years
13  Conservative  values  of  expected  ground  accelerations  at  the  dam  sites  of Negeso and Upper Beles from deterministic approach
Comparing different models for attenuation and geometrical spreading we suggest conservative ground acceleration values at the dam sites in the order of 100 cm/scc ■ equivalent to 10 % of g (O.lg).
1.6        Maximum Credible Earthquake. MCE
The MCE is estimated to 5.7 and the corresponding maximum intensity at the dam sites is in the order of = 8.5.
1.7        Resonance/ reverberations/ liquefaction effects
We emphasize that the low-frequency range of raduted seismic waves is overlapping with the Eigen-frequencies of civil constructions (0.01 - 1 0 Hz) and also those of alluvial materials of the overburden down to the bedrock at the dam sites.
1.8        Induced Seismicity
For the sake of completeness we mention here also the forthcoming hazard of indeed seismicity. This hazard refers to se.sm.ctty in the areas of the dam lakes. Extra seismic activity mighi occur dunng and after Filling of the reservoir due to the
vefliwi load of .he a a,„. 1„ addmon; i„
pcnelraung  imo  .he  ground  may  act  as  a  lubnca.o,  ,£„bv s Ires.«s. A classical exampk of induced »OTicily „
Xer.
^.a
4duccd seismicity, the seismic activity at any dam site, covering also the focont^1 •"u monitored already prior to filling of the reservoir. This will then
^(voir. s -son of seismic activity prior and after loading. Induced seismicity,
provide a t0^ilces normally only earthquakes with rather small magnitudes.
howe'tr» P
Introduction
(ified to argue that the gradient of the geologic and tectonic evolution 11is *C|. "African Rif* Valleys and the Red Sea. has been a fairly constant process ,l0n" * *1 gical times. Continental rifting and its consequences by crustal
ove g  n elated geophysical processes and tectonic evolution have been ongoing
re
^^■rsscs'ovcr the last hundreds of millions of years, whereby a time period of several P^es i e the life time of a dam. practically is of no significance
Th design and construction of a dam should also take into consideration the hazard of earthquakes in the vicinity of the dam site Hereby it is of importance to study in detail the following:
•   the geographical (spatial) and temporal distribution of seismic energy release in the region;
•   the delineation of the most active faults and tectonic activities;
•   the provision of a deterministic approach to calculate ground accelerations as a function of magnitude, epicentral distance and focal depth;
•   estimate of a maximum conservative earthquake to be expected in the region of investigation;
•   estimates of recurrence periods for different magnitudes;
•   the deployment of a probabilistic analysis for earthquake design of dams in accordance with ICOLD guidance at detailed design stage;
•   proposal for geotechnical investigations. Static approach (deterministic calculation of conservative ground accelerations) versus dynamic analytical methods involving precise quantitative data on the physical properties of the foundation soils and rocks beneath a construction site.
RReegi giononal al T Teeccttononiicc A Accttiivi vittyy
J^niain physiographic components governing the project areas at Upper Beles and CS °can be divided into three different regimes (see Fig.I):
sian)NOrthern Part °f ,he Western Branch of the East African Rift (Southern
"'^udcs'th'1 S ,Ocated to west of the project areas at Upper Beles and Negeso and Valley C ^^hem extremities of the western section of the East African Rift
*cl| csUbr h rCgi°n is high’y objected 10 earthquakes and crustal deformations is thcrn pr ‘ by legcnds of the local tribes that enshrine a tradition handed on to
,30|tm alo^T °CCUpanls of local districts. The most active area stretches for about c gorge between Gondogom and Dufile.
5We refer, for instance, to the earthquake of 20 May 1990. located ‘
,hcrn
°“
5.12° N and 32.15° E. With a magnitude of M = 7.2 this earthquake" S
l
the largest ever recorded in the region (southern Sudan- Main Ethio * bclievcd to bp’1 Buildings collapsed in the Juba area and damage was also reported
district, Uganda. The event was widely felt in the Nakuru area. Ken " ^ay°
The focal depth was estimated to be rather shallow, i.c. 15 km* About*so d ^antJa
and the financial damage was significant.
* P^Ple diy
According  to  the  damage  in  the  epicentral  area  wc  adopt  a  maximum  intensity  of  - XI.  The event occurred at epicentral distances of about 620km to Ncgcso and about 880 km to UppeT Bcles. suggesting local intensities al these sites between I = V -V|.
3.2      Main Ethiopian Rift with Extension into Afar and Red Sea (Central Ethiopia)
The northern part of the East Afncan Rift is known as the Main Ethiopian Rift, which is north- south trending and extends to the north into Afar and the Read Sea. The opening of the rift, al a speed of about one cm per year, constitutes the fragmentation of the African continent, where East Africa is diverging (breaking off) from the African main continent into the Indian Ocean.
Extrapolating over, say, a period of four million years, we expect the main continent to be separated from East Africa by a sea with a width of about 50 km. thus approaching today present situation of the Red Sea. The process of fragmentation of the continent along the rift is associated with tectonic activity and related crustal deformations, manifested in seismic activity, volcanic activity, surface fissuring, faulting by lateral extension, land sliding, etc.
The northeast trending Main Ethiopian Rift cuts across the Ethiopian Plateau, which has been interpreted as thermally elevated above at least one mantle plume. Flood basalts from 31 to 29 Ma over a region about 1000 km in diameter arc thought to reflect the impact of the plume head beneath the continent. Geophysical evidence indicates a deep- seated thermal anomaly consistent w ith the presence of a plume, with anomalous low P-wave velocities.
when defomtanon migrated toward, a „,nc eoleantsm and l.ulw Ioe.ltzed to ata, 20 tm Wldc nft These magnetic segments include nfi
H 77
.
” S"8g‘‘“ “
between 6.5 and 3.2 Ma.
,£
, M„.
• . . ^2 3
„
.
-*..
north-northeast trend that is oblique to the overall*^ h young ^au*! segment, are separated from one’
echelon pattern, and show little correlalton with the ho <1 "r is in the order of 9 mm/yr as calculated froZJ,,
idtcTd le
™
category of ultraslow spreading ndges 
° ns’ Pac,n£ *^c n*r 10 °
rw-akinn. models of continental breakup remain uncertain because
o f a lack 
Generally spe
i  accumulation immediately before breakup. Recent nc* .
stra n
of knowle gc
dimensional modeling in the Main Ethiopia Rift and Afar    *
1c
obtained from inlrusions in this active, transiuonal nft setting, supporting images H'^'.^^ascd on dike intrusion and magma supply,
breakup model
6Ung features in this model are anomalous fast, elongate bodies (velocity Then'P , 5_6.8 km/s) extending along the rift axes, interpreted as cooled mafic 
V
j ntnis|0"2nta| brCakup in magmatic provinces as a locus of extension in transitional
( ,f coolin'(hal faults abandoncd prior t0 continental breakup. We
nf 5ClUJ g mafic intrusions about 20 km wide and 50 km long, generally located
p ab?u s Yhcse recent results lend support to the Ebinger and Casey (2001) model
aC
clCarlyh'the magmatic segments, which are obliquely orientated with respect to the
bf "eal f ults and accommodate extension in the center of the rift valley. The width of
^bodies is compatible with 27 km extension predicted in the last 3.2 m.y. from
*•** otions These separated inid-crustal intrusions may ultimately form the
for a segmented mid- ocean ridge.
The orientation and the cn echelon geometry of adjacent magmatic segments may be a 1 eauence of the rotation of the least compressional stress direction from
northwest- southeast in the late Miocene- Pliocene, in which case the length of the segments would be controlled by the angle of rotation of the stress field and the width of the rift
In conclusion, a new seismic velocity model from the Main Ethiopian Rift constrains a continental breakup by imaging axial intrusions in the transitional nft environment. Magmatic processes appear to dominate the volcanic rift settings immediately before breakup and control the location of incipient seafloor spreading. Above the intrusions, a combination of normal faulting and dike intrusions accommodate extension in a brittle upper crust. The magmatic segments form the proto-ridge axes for future seafloor spreading.
33 Intra-plate Region between the Main Ethiopian Rift (Central Ethiopia) and the Northern Part of the Western Branch of the East African Rift (Southern Sudani.
This vast area stretches between eastern Ethiopia and western parts of the Sudan, including the project area of the study in general and the dam sites at Negeso and Upper Beles in particular (see Fig. I). Wc classify the area as an intra-plate region, *hich is relatively stable and. generally speaking, free of seismic activities. This is immediately obvious from Fig. 1
owever, intra-plate stress accumulation, due Io stress migration from the nearby atonic rift settings, may occasionally be released within intra-plate semi-rigid plates 
wl)CVCrCl 1^88), when tectonic stresses reach the threshold in intra-plate section geo'°8lcal weaknesses prevail (Voigt or Maxwell bodies). Thus, we may 
Cl m’nor earthquakes in the magnitude range lower than 3.
free of WC concludc that the dam sites at Negeso and Upper Beles arc practically Jean (1*97^ ° ac^ ^y* data set displayed in Fig. 1 covers a time window of 33
tr ^no j
v
activity h* 2^05) and. searching in earlier catalogues, we do not find any seismic y a> distances less than 200 km from the dam sites.
h
Since insf            *n °^er catalogues, wc find the event of 12lh of December 1845. r  s h TnCnla^ data *s not available from that time, all information about this 
and repo-
a Scd On m
.          *cro seismic observations. On the basis of observed intensities 
destructions the magnitude of this event was estimated to 6 % to 6 W.
7The adopted epicenter is 12.25° N and 39 E. which places the tremor to the wCsie
plateau, just outside or peripheral to the well established western escarpment of,?
rift (see Figs. I to 3). A summary of known macro seismic observations is g,vCn
Appendix 3.
We  note  that  the  epicentral  distances  to  the  dam  sites  of  Ncgcso  and  Upper  Belts  arc 810 km and 445 km. respectively.
In comparison and in contrast to the well adopted epicentral solution (12.25° N and 39° E), Siebcrg denote the area of maximum intensity to just south of Lake Tana, at about 11.3° N and 37.3° E. This location provides distances of about 500 km and 145 km to Negeso and Upper Bcles respectively.
4.           Seismicity
The regions of central-western Ethiopia and southeastern Sudan include the project dam sites al Negeso and Upper Beles. Seismic energy release in this wider grid is considered in the seismic hazard assessment at the dam sites. The search for data includes mainly:
1.  A complete catalogue of instrumentally recorded earthquakes, given by the National Earthquake Information Centre of the Geological Survey ot the US This data covers a period from 1973 - 2005 and is to be regarded as complete and homogeneous with regard to earthquake magnitudes.
2.   An earthquake catalogue given by Goum (1979): Earthquake History of Ethiopia and the Hom of Africa, Due to the absence of seismograph stations in earlier times, this catalogue is not complete for medium and lower magnitudes.
In all. the data considered in this work is well representative of the ongoing seismic activity within the areas prone to seismicity, which may have an influence on the construction sites at Negeso and Upper Beles. The lime period used here covers all historical data and all instrumental data to 2005 and thus it may be justified to extrapolate this data set into the forthcoming decades, anticipating a continuity of tectonic and geologic evolution in the region.
The ^nd within the coordinates of latitudes 4.0°- 16.0  north and longitudes 32.0°-
u
42.0 cast covers the region involved.
Instrumentally recorded data by (he National Earthquake Information Center of the USCGS. 1973 - 2005 is given in Appendix 1. a total of 240 events. This catalogue is rather complete down to a threshold magnitude of about M = 4.5.
Gouin s (1979) data go back to earlier centuries, starting tn the 16*’’ century, and ends ] 977. Thus, the two data sets arc overlapping for the time period 1973-1977.
The geographical distribution of epicenters from Appendix I is revealed in Figs. I t° 3. From these figures the tectonic activities in the three different regions involved, i-^* Southern Sudan (section 3.1), Central Ethiopia (section 3.2) and the vast intra-plate
8deluding lhe project sites of Negcso and Upper Beles (section 3.3) become obvious.
scenting Negcso only onc5^°?l^bc foundat an epicentral distance of less 
f non km- J991, magnitude M =4.4, distance 188 km. than iu"’
, ne Upper Beles the closest seismic event that could be found
was a very
( ^C event
7
in I" - magnitude M = 3.8, distance 265 km
rth( U
] akes with magnitudes larger than 6.2 or with extreme intensities larger than VW are displayed in Fig.3. Considering the NEIC data (1973- 2007) we find 4 events 
th M larger than 6.2. The outstanding largest event in this time window occurred in M = 7.2 (Southeastern Sudan).
Even though the project areas at Negcso and Upper Beles are considered as parts of a semi- solid mtra-plate region, thus practically aseismic, we have to consider the impact of the larger events (see Appendix 2), even though at large epicentral distances, in the seismic hazard analysis.
An interesting feature of regional seismic energy release is displayed in Fig.4. where we have plotted the annual activity for some selected years, i.e. for 1987 (green circles), 1989 (blue circles), 1993 (red circles) and 2005 (yellow circles). We sec immediately that seismic energy release is migrating within the region.
5.      Frequency of Occurrence-Magnitude Relation
Generally speaking, the number of earthquakes is related to magnitude through the relation
Log N (M) = c-bM
where N is the number of events for a given magnitude M. The constant b may be considered as a tcctono-physical constant, reflecting the rheology of the area. This constant differs generally from one seismic area to another and may vary from 0.4 to IJ The other constant, c in (1). depends on the time period involved and the size of
•** area considered.
Jl* geographical grid employed here includes different tectonic settings (see 3.1, 3.2 o' h 2nd We WOLdd expect some differences in the values of b and c in equation I haz d r ,*'Cr hand we cons>dcr the data in Appendices I and 2 to have the same
for lhc construction sites at Negcso and Upper Beles and therefore we analyse 3s one set with regard to the evaluation of the constants b and c.
1 nstn^UmCr’Cal valuation of (1) we considered the homogeneous data set of 33 Vermally rccordcd events in the time window 1965- 2007. i.e. a time window of activi"'; *hlch be regarded to properly represent the currently ongoing seismic 
y,n the region.
(1)
9We deployed a threshold magnitude of M - 4.5. arguing that the earthquake coUnu bHow M - 4 4 are not complete. This consideration is simply related to the configuration of the monitoring network, which provides complete magnitude dala only above a certain magnitude threshold, m this particular case to he chosen ,0 M = 43 The total number of events used for the evaluation of (1) is therefore rcduccd |0
155.
Table 1 Earthquake counts, N, per 0.4 units of magnitudes, M, for the d
Appendix 1 
’
In
Magnitude range
M
Mean
M
No observed
N
No calculated
N
4.1-4.4
4.25
55
not used
J
4.5- 4.8
4.65
89
89
4.9- 5.2
5.05
41
41
5.3 -5.6
5.45
16
19
5.7- 6.0
5.85
5
9
6.1- 6.4
6.25
4
4
The optimal least-squares regression for these data points reads
Log N(M)= 1.95-0.84 (M-4.65)
The graphical distribution and the regression arc displayed in Fig. 5. The
interpretation of (2) may be exemplified as follows:
Example 1:
(2)
How many earthquakes in the magnitude interval 6.1 - 6.4 may we expect in the region (Southwestern Ethiopia- southeastern Sudani in the next 33 years?
Log N (M = 6.25) = 0.606
N = 4 earthquakes in 33 years
Example 2:
How many earthquakes within the magnitude interval M = 6.1 - 6.4 may we expect in the region within the next 50 years?
N (50 years. M s 6.1- 6.4) = 50/ 33 x 4. i.e. abou, 6 e hqu3k„ „
In this case the numerical value of the constant .. n <_ a ported of 33 rears For a pood „f 5,. ye^ "
*” <2’C W. “. dcn"'d 1
(hivalpe   of   log   (50/33)   =   0   18.   The
value
,
Recurrence periods estimated from (2):
c ,orc 150
years) would thus he 1.88 + 0 l« '
for   tn   w"   ‘   Cl""SC
10. interval M * 5.7’ 6.0. about 9 events per 33 years, equivalent to about one
i interval M = 6.1 -6.4: 4 events per 33 years, equivalent to about one event
Magniiu^ in,c
t event recorded was that of May 20. 1990. in southeastern Sudan.
Thelarg^ M = 7 2. This was the largest event ever recorded in the region, probably yfagnitu * continent. We may argue that the size of this earthquake. M = 7.2, refers 
threshold of stresses which may possibly be accumulated before
iXX oftectonic/ gColOg'C structures
r 2 ) to obtain a rough estimate of a recurrence period of these major
^Tuakes and following the extrapolated regression line in Fig.5, we would look at of log N ( M = 7.3) of about - 0.6. This would refer to. say, a recurrence
1 od of these type of major event, magnitude interval 7- 7 !6. in the order of one
^ t every one hundred years. The region where these events occur should probably 
n
be classified as tectonic asperities.
6 Concept to Estimate Maximum Ground Accelerations
Ground accelerations may be estimated by a probabilistic or deterministic approach. Initially, we follow below the deterministic concept of Bath (1975). which was developed for East Africa (Tanzania) and may thus be applicable for Ethiopia / Sudan. From these calculations is easy to estimate the ground acceleration, due to radiated earthquake waves, at any site of interest, i.e. civil construction site.
Following Bath (1975) the acceleration, a, experienced al a point on the earth surface at an epicentral distance, r, for a magnitude. M, and at a focal depth, h, becomes a function of three variables
a = a (h. r, M)
Considering the effects of geometrical spreading and assuming spherically symmetric ation of seismic waves from a point source at depth h in a homogeneous half
s Pa«, we gel
(3)
a = 1.03 h° 6 10° 54 M / (r2
+h)
2 JM
(4)
Equation (4 *S
d*s,ancc (epicentral distance r and focal depth h) and a given to ca,culatc estimate for the acceleration expected,
curves 
rcy * ls Ethically illustrated in Fig.6. From this figure it is obvious that the
local max *
max ma
’    Derivation of (4) with respect to h or r. show that these
Nation fn?13 °
C CUT at r
.          = 1 22 h. Substituting h = r/ 1.22 into (4) we obtain the
max>mum acceleration
a = 0.62 ]00MMr 0’
(5)
Elation is
displayed in Fig.7 for magnitudes 4, 5, 6 and 7.
IIIf we also substitute magnitude M into (5), we get even simpler relaf maximum ground acceleration as  a function of epicentral distance for magnitudes)
various
a rail = 25r'°’
a fn„=87r0’
«mu = 31lrA’ a™ = 1077 f*’ a m„ = 3737f°’
for M = 3
M = 4
M = 5
M=6
M=7
(6)
Once a construction site has been decided upon, and considering the known seismicity in the vicinity of the site, it will be straight forward to get estimates of probable
ground accelerations for any specific site in the basin
7. Macro-seismic Observations and Intensities
Macro seismic hazard describes surface deformations in the vicinity of the epicenter of an earthquake. Data is hereby received from individuals, who describe their observations, which arc then graded into the international Mercalli scale.
Ground accelerations and intensities arc interrelated. Qualitatively speaking; the larger the ground acceleration, the larger the intensity. The Mercalli Intensity Scale is graded from I = I io 1 - 12, whereby intensity I = I refers to only instrumentally observable intensities (not observable by human beings) and the extreme intensity oi I = 12 refers to situations of total destructions.
The 12 degree Mercalli Intensity Scale must not be confused with the magnitude scale, which is on open logarithmic scale. Intensity is therefore a measure of the locally observed ground accelerations, which is large in the epicentral area and which decays rapidly with increasing epicentral distance (cf equation 6). The magnitude, on the other hand, is a measure of the total amount of energy released in the focus (hypocenter) and is therefore a constent value for each individual earthquake.
The descriptions of the higher degree intensities on the Mercalli Scale read: I = S Damage slighl in specially feigned 51nrai,res. c >ns|detabfc „ subslanlia|
,
buildings. »Kh partial collapse; greal in poorly bu,|d slruclures.
1 =  9 Damage considerable in specially designed buildings, with partial collapse; ground is cracked
structures; great in substantial conspicuously.
IQ. j^ost masonry structures destroyed as well as some well-built wooden strictures; ground badly cracked, rails bent; landslides and rockslides
121*'
- jf any. masonry structures remain standing; bridges destroyed; broad 1 -around; earth subsidence and landslide in soft ground
fl0 unreress*
|s|2: Damage mw/
already seen that the dam site areas of Negeso and Upper Beles are located * f  ^^smic  intra-plate  region,  which  is  free  of  earthquakes  within  radii  of  at  least
m an
ascl
other hand, major earthquakes outside the immediate vicinity of the project
1 C  wc|| have impact on the dam structures. In Appendix 2 major earthquakes,
5,leS’™(0 the tectonic active regimes of the Main Ethiopian Rift- Afar- Southern Red ^Mid the Western Branch of the African Rift (southeastern Sudan) are listed.
ddition macro-seismic observations for some selected destructive major events are "sen in Appendix 3 (Western Plateau- Lake Tana region. 1845). Appendix 4 (Shoa
Evince- Lake Ziway region. 1906) and Appendix 5 (Wollo, 1961).
Having intensity data available, ground accelerations can even be estimated through the approximate relation
2
L = 3 log ao + 1.5 (ao expressed in cm / s )
where Io is the maximum intensity in the epicentral area and ao refers to the corresponding ground acceleration.
Foran intensity of I« = VIII we would then get a maximum ground acceleration of ao = 147 cm/sec . valid for the immediate vicinity of the epicenter of the earthquake. As 
(7)
2
we know, however, the maximum acceleration in the epicentral areas decreases with increasing distance from the epicenter, due to attenuation and geometrical spreading (s« section 6).
Asfaw (1982) provides an attenuation formula based on data from the Afar depression, probably extendable to tectonically active regions in the Sudan
I = 2.15 -2.43 log R + 1.55 M
a ? We    *S    hypoccn,ral    distance.   It   is   obvious   from   this   relation   that   the nuation of the intensity decays slowly with distance.
Engineering Implications
(8)
and Upnc’' if
°f expected ground accelerations at the dam sites of Negeso
P^vided  l'CS  Can    °btained  from  estimates  of  ground  accelerations  (Bath.  1975)
° bservaU ? *** earl'er
of this report or, if available, from macro seismic
ns . deploying also the intensity attenuation relation ( 8 ) of Asfaw (1982).
138.1 Conservative estimates of ground accelerations from instrumentally recorded earthquakes
According to the earthquake data given in Appendix 1 and in Appendix 2, wc Ca find events of significance for earthquake hazard in (he aseismic vicinity of N Z'
c
no ‘
and Upper Belcs. Wc therefore estimate probable ground accelerations of some cv° along the tectonically active regimes at some larger distance.
Table 2. Estimates or Ground Accelerations following the Deterministic
Approach under Section 6.
eiMs
location
Epicentral Distance
km
Ground Acceleration
cm/s2
Western Plateau- Lake Tana Region 1845, M = 6.3, N 12.2*, E 39.6*
Negcso
510
5.7
Upper Belcs
310
8.9
Shoa Province- Lake Ziway Region 1906, M = 6.8 N 9 , E 39°
f
Negcso
290
17.8
Upper Bcles
370
14.2
J
Kara Kore- Western Plateau Margin 1961, M = 6.7 N 10.6°, E 39.3°
Negcso
380
12.2
Upper Belcs
360
12.9                   j
Southeastern Sudan, 1990, M = 7.2
Negcso
620
14.7
Upper Belcs
880
10.7
2
According to equation (7), a ground acceleration of a = 10 cm/s would correspond to
2
an intensity of I = 4 MAn acceleration of 20 cm/s  would yield an intensity of
I=5h
8.2      Estimates of ground accelerations from macro-seismic observations
Whenever intensity data and epiceniral distances arc available, we may follow equations (7) and / or (8) to gel an estimate of ground acceleration
For comparison between the attenuation concepts of Bath (1975; and Asfaw (1982) we attempt to get estimates of ground acceleration for the upper threshold event of southeastern Sudan. 1990. magnitude M = 7.2.
|42
1
„ Asfa* (1982. equation 8) we first calculate the intensities at Negeso and
, eS which would yield I = 6.5 at Negeso and 1 = 6.1 at Upper Bcles. Using
L'pF*, , (7) we then get acceleration values of 47 cm/s  and 32 cm/s  at Negeso and
fi les respectively. These values are to be compared to about 15 cm/s’ for
L 'pper nd 11 cm/s2 for Upper Bcles. The difference is apparently bv a factor of 3 ScgCS° aooroach by Asfaw (1982) suggests the higher estimates’
u hereby
Estima«e of conservative ground acceleration at Negeso and Upper Beles
8J
daffl Sit**
the discussions under 8.1 and 8.2. we would then expect ground accelerations to ^considerable lower than l(X) cm/sec’ (= 0.1 g) at both dam sites.
The value of 0.1 g is thus a rather conservative value for the civil works of dams at
* ant] Upper Bcles. This value must be considered low in comparison to ground acceleration values expected and designed for in other regions of the African Rift. We attribute this low value to the location of the dam sites in an intra-plate region of
extreme low seismicity.
Other dam sites in the African Rift System, having intensive seismicity problems and thus higher seismic hazard, adopted much higher design values. MacDonald (1987) used 0.3 g for Kcsem. At Tendaho. Gibb (1975) reached the following conclusion:
•   there is nothing to preclude the possibility that an earthquake may occur
within the lifetime of the dam at the dam site or within its immediate vicinity.
•    no limit can be placed on the magnitude of such an earthquake nor is it
possible at present to estimate its duration.
Wc conclude that ground displacements and associated accelerations in the vicinity of engineering structures constitute a hazard which is not easily amenable to methods of a seismic design, although choice of materials could mitigate consequences of failure.
84  Maximum Credible Earthquake, MCE
Having estimated a conservative ground acceleration of 100 cm/s2 (O.lg) we calculate ^corresponding Maximum Credible Earthquake, MCE. using (5). Earthquakes in the
and vicinity are crustal events and thus we adopt a typical focal depth of
w. With this assumption we would have a hypocentral distance of h = 10km and
1 Would yield a value of MCE = 5.7.
Th
wonM^'mum  intensity at the dam sites of Negeso and Upper Beles. for MCE = 5.7. ^‘dbearound 10=8.5.
Recurrence periods
adjacent r 5
r
Currencc periods of significant seismic energy release (M > 6) in the
a C(^1?ns dam s’tcs at Negeso and Upper Beles are well within the
ani icip i
and Upper R ^'*mc og a cis'il construction (see under 5). For the dam sites at Negeso n       C Cs' ’OCatcd in an intra-plate. rather stable, shield, wc cannot predict any 
:c cun> <-
Cntc Period.
159. Ground Vibrations, Resonance and Liquefaction
Seismic energy, generated in the hypocenter of an earthquake during d tectonic blocks, produces ground vibrations with particle motions in fo'S °Ca,'° ’>f
n
compressional and shear waves, which radiate from the source in a 3- d‘
pattern. The frequency content of these waves in the source may vary fr rnCnsiona* several hundreds of Hz (cps). High frequency components arc rapidly 
’°
increasing  distance  front  the  source,  whereby  the  transmitting  medium  act"  p?**1    *ilh
filter.
Along the surface of the earth the vibrating earth particles shake the overburden geological structures The shaking of the ground weakens soils and causes dramatic changes in fine- grained soils. During an earthquake, water saturated sandy soil or clay becomes liquid like mud. This effect is called liquefaction and once this effect is active, it leads to dislodging of large earth and rock masses, producing also dangerous landslides.
s ,lkc a
The magnitude of ground acceleration, related to the size (magnitude) of an 
earthquake, is of course of great importance Acceleration values may be estimated 
from any deterministic analysis or can be taken directly from accelerograms, if these are available. An equally important factor to ground acceleration (magnitude) is the frequency involved. A typical dry soil has an Eigen frequency (resonance frequency)
in the range of 2-5 Hz. This, however, is also the frequency range that carries the main 
part of the seismic energy, which has not yet been attenuated at the distance involved 
It means that any earth material, geological structure or any civil construction along 
the surface of the earth, having Eigen- frequencies within this frequency range, may 
get into resonance. If the soils are wet the resonance frequency may go down to 1 Hz.
A typical rock soil may have a some what larger resonance frequency in the vicinity 
of about 10 Hz. For typical soils, dry or wet, we may therefore argue that their
resonance frequencies are to be found in the range of I • 10 Hz. This is also the range
of resonance frequencies of much civil construction.
Previous spectral analysis of seismic signals has shown that the essential part of the
seismic energy is carried in the frequency band from 0.01-10 Hz. matching the
resonance frequency band of geological materials and civil structures.
Il  is  very  likely  that  liquefaction  and  resonance  effects  wiU  support  each  other  towards damage along the surface of (he earth.
10. 
for
5p
^,
rc
Generally speaking there are two methods of aehi- engineering structure. The previously deployed 
3 dcs,gn for an
seismic waves as a steady  ground  force corre ,,IOna^ approach  represents the percentages of g’ or in  ctn/s:. This will lead^o^a^"8 *° acL'eleraflon expressed  in over-conservative, because of simplifications " "*  W*1’c*1 *s safc< *>ul *s n,osl^
of a regional seismic zonal building code whi'-h 
lnstancc deployment
variations at specific sites). Already here signifi Sn,oo,h,ng out laterally local
a region Assuming that the regionally adonis if ?
• P'M building code is a conservative value
3    Variations might be found within 1C region, any local deviation within the region (determined by a rather for tl»c is) Can provide a lower seismic hazard and thus a more favorable
cheap «nal-. wj(h rcspect to construction costs.
tHjilJingc00'
considerable savings in construction costs can be achieved by basing the
|n addition^ of & dynamic analysis. Such analytical approach requires precise
de5 'gn°tn vc data on the physical properties of the foundation soils and rocks.
‘ ,U hiding their response to the seismic energy carried in critical frequency ranges (sec section 9).
ujrtd data will he obtained by a combination of in-situ testing of the ground hvsical field investigations and tests, core drilling) and tests in the laboratory 
<gC°P undisturbed and representative samples of all foundation materials. The
U '"each includes highest possible standard of core drilling, deploying good standard Snologyand personal.
Investigation along construction sites should provide additional geophysical and geological information, requesting information concerning:
• Determination of the thickness and nature of the overburden material
• Determination of the nature and depth to the bedrock
Ground investigation referring to the dynamical approach, recommended for instance at a dam site or any other engineering design, will also delect and outline geological structures, including faults, contacts and weak zones of geological pockets. These demand more costly site investigations, such as in-situ and laboratory tests on soil samples, seismic refraction profiling and core drilling (core sample analysis).
11* References
Asfew. L.M., 1982. Catalogue of Ethiopia Earthquakes. Earthquake Parameters, Strain Release and Seismic Risk. Proc. SAREC/ ESTC, pp 252-279.
M„ 1975. The Seismicity of Tanzania. Tectonophysics. 27. 353 - 379. Geological Survey of the US. National Earthquake Information Center. Report*p Partners. 1975. Feasibility Study of the Lower Awash Valley. Final
Goui 257 pp  "
P   1979 Earthquake History of Ethiopia and the Hom of Africa. Monograph.
acb °nald. Sir M & Panners Ltd. 1987. Kesem Irrigation Project. Feasibility Study, "eyer. Km
'O piate SSOn’ R- and Scherman. 1988. Stress migration in the North Atlantic and Wor^hoD pSmici‘y in Scandinavia. Presented at the NATO Advanced Research 
Copenhagen. Tectonophysics. 156. 175-178.
17Fit E Seismicity of Centra) Ethiopia (Main Ethiopia Rift) and extensions into Afar and the Red Sea and the northern section of the western
branch of the African Rift (southeastern Sudan). Note (I) within a grid 4°- 16° N and 32°
42° E. (2) epicenter locations are denoted by open circle.*
(3) Ume period \*JT3- 10GS (33 years') (4) note the aseismic behavior of the intra-plate region between lhe tecConicrdf y action region*' a.v.so<7are<f wif/i ctic- Atncan iSoulhe astern Sudan) and uath the Main EOuaptan Kifi.f
Figure.2. As in Figure. 1, overlaying the regional geology
19Figure.4  Regional  migration  of  seismic  energy  release.  1987  (green)  southwestern  Ethiopia,  1989  (blue)  northeastern  Ethiopia*  eastern  Afar,  1993 (red) western Afar. 2005 (brown) centra) Afar.Figured Frequency of occurrence- magnitude regression. The chia points denote center values of magnitude intervals of 0.4 magnitude units. The computed regression reads Log N = 1.95 - 0.84 (M- 4.65).
2250                 10O               150               200               250               300
Figure. 7 Graphs for maximum ground acceleration, a.... versus epicentral distance, r, valid for focal depth h = r / 1.22. The examples for M = 4 (lower curve), M = 5. M = 6 and M = 7 (upper curve) show a rapid decay of acceleration values with increasing epicentral distance r.
23APPENDIX  1:  Catalogue  of  instrumentally  recorded  earthou  L
western Ethiopia/ Sudan after 1973. 
Grid coordinates:        Latitudes 4.0° - 16.0° north Longitudes 32.0° - 42  east
8 '
fl
Y. M, D
H.MtS
LAT 
LON
Mb
Y M D H Mt S
Year. Month, Day Hour. Minute. Second Latitude degree north Longitude degree east Magnitude
1973     01    07    12   17   12
1974     02    25    16   05    15
1975     04    16   02   55   08
1975     08    07   22   43    13
1975     08    23   21   35   21
1976     08    06   29   32   26
1976     11   07   05   53   07
1976     11   07    20   21   47
1976     11    16   12   53   33
1976     12   01   05   03   38
1977     07    08   06   23   02
1977     12   05    10   02   57
1978     05    12   06   20   06
1979     08    06    00   48   26
1979     08    15   02   20   43
1979     09   19   18   48    12
1979    11    10    17   42   44
1979     11    13    17   01   36
1983     08   31   17   30   43
1983     12   02    23   08   39
1984     04   10   08    10   38
1984     10   12   06   38   29
1984     10   13   02   28   59
1985     08    14   20   37   44 1985     08    20   05   46   00 1985     10   28    12   08   36 1985     12    18   02    15   34 1987     01    22   04   21   04 1987     09    15   00   00   26 1987     10   07    22   29   24
LAT LON Mb
5.27      36.85 9.84      40.03
14.63 15.29 10.62
13.20 
15.82
15.95
15.90 15.87 10.94 12.69 13.00 12.55 15.39 12.24 14.88 13.22 12.67 
7.03 
11.37 
14.65 
10.58
8.30
5.32
9.46 
4.70 
1236 11.34
6.22
40.69
40.41
39.73
39.76
41.42
41.47
41.92
41.68 19.63
40.47
40.01 
40.67
41.70
40.36 39.64 40.05 40.61 38.60 39.71 40.32 40.03 38.52 36.14 39.65 
33.20 
41.30
41.58
37.81
4.9
4.5
4.5
4.6
5.2
4.7
4.8
4.7
4.9 4.8
5.0
4.5
4.8
4.5
4.7 5.0 4.3
4.2 4.8
5.1 
5.0
4.1
4.9
5.4 4.7 
4.3
4.3
5.3
241987    10
1987    10
1987    10
1987    10
1987    11
1987    12
1988   03
1988   04
1989   04
1989   04
09 03 49 17
25 16 46 13
25 16 57 58
28 08 58 29 
12 10 35 02
31 03 07 12 
23 23 55 08 
30 16 25 05 
12 05 05 15
13 07 55 11
5.47
36.00
4.7
5.41
36 75
6.2
5.11
37.21
4.7
5.74
36.73
5.6
5.51
36.87
4.3
11.37
41.75
13.68
40.56
4.9
4.79
35.40
4.2
13.31
39.98
5.0
13.26
39.92
5.2
1989 04 13 12 17 31 
1989 04 13 12 35 04 
13.29
39.98
4.9
13.34
39.96
4.3
1989   04    13    13    00    48 
13.35
40.01
4.8
1989   05    11   20    53    51
8.95
39.98
5.0
1989   06    08    06    24    09 
6.84
37.88
5.0
1989   06    20     17    35     23
12.66
41.93
3.3
1989   06    20    21     11    51
12.69
41.83
4.5
1989   08    20     11    16    56
11.77
41.94
5.8
1989   08    20     11    17    55
11.92
41.96
5.6
1989   08    20    11   46     28
11.88
41.81
6.1
1989   08    20     11    56     17
11.76
41.96
5.3
1989   08    20     12    13    36
11.47
41.71
4.8
1989   08    20     13    25    26
11.90
41.88
5.1
1989   08    20    13    26     19
11.88
41.88
6.1
1989   08    20     14    15    43
12.04
41.63
4.6
1989   08    20     18    25     13
11.81
41.81
4.3
1989   08    20     18    27    33
11.82
41.58
5.1
1989   08    20     18    39    48 
11.98
41.87
5.4
1989   08    20     18    54    05
11.90
41.76
5.2
1989   08    20    19    25    56
11.90
41.72
6.2
1989   08    20    20    45     12
12.16
41.61
4.7
1989   08    21    01    09    06 
11.87
41.87
6.0
1989   08    21    01     34    07 
11.99
41.89
4.9
1989   08    21    05    03    05 
1989   08
11.94
41.77
5.8
1989   08
21    05    05     45 
11.82
41.73
5.3
1989   08
21    07    07     38
11.80
41.72
5.0
1989 08
1989   08
1989   08
1990 05
1990 05
21 09 04 11
21 18 10 38
21 21 21 35 
22 03 01 48 
04 10 12 06
12.30
41.25
4.2
12.07
41.68
4.6
12.10
41.65
4.6
12.19
41.53
4.8
11.75
40.96
5.2
1990   05
16    17    17    23 
11.89
41.76
4.0
20    02    22     01
5.12
32.15
7.2
251990 05 20 36 41 23
1990     05    25    01    02    21
1990     05    26    05    53    50
1990     05    26     14    39    51
1990     05    27     18    56    56
1990 05 29 04 37 29
4.54        32.18         4.6
8.13        32.03         4.7
5.32        32.04         4.8
4.84        33.64         4.6 13.13        39.93         5.0
5.47 32.57 4.7
1990     06   03     16    23    39
5.44
32.12
5.1
1990     06   06    01    28    30
6.18
33.48
4.7
1990     06   09    08    06    03
5.45
32.02
4.7
1990      06   30     10    17    45
5.27
32.38
3.9
1990     07    13    10   41    33
6.77
32.12
4.2
1990     07    15    15   08    28
5.00
32.19
4.8
1990     07    27    20    41    31
5.07
32.08
4.8
1990     07    28    06    54    45
5.29
32.11
4.3
1990     07    28    16   46    02
5.22
32.60
5.3
1990     07    28    17    17   33
5.23
32.33
4.4
1990      12    11    05    09    08
5.35
32.64
5.0
1991      01    05    15   47    49
5.14
32.08
4.9
1991      01     08    16   09    30
5.36
32.54
4.7
1991     01    31    06    13    10
5.31
32.60
4.6
1991      02    03    14    46   43
5.36
32.49
4.6
1991      02   09    08    45   55
5.20
32.47
4.8
1991      03    15    08    22   54
5.72
32.30
4.8
1991      03    29    09    06    06
5.51
32.67
5.4
1991      03    29     16   54    31
5.41
32.95
4.8
1991      07   26     15   33    38
7.57
37.67
4.4
1991      09   06     16   08    34
5.34
32.15
4.9
1992      10    12   23    42    09
5.02
32.02
4.9
1992      10    13    16   22    11
4.79
32.11
5.0
1992      12    22    10   36    33
11.98
41.77
4.3
1992      12    23    18   42    46
12.80
40.92
3.9
1993     01    21    01    15   33
12.62
40.61
4.9
1993      02    13   02    25   49
6.33
39.31
5.3
1993      03     16   22    59   45
11.62
41.99
5.6
1993      05    01    07    57    13
14.76
40.50
4.2
1993      05    02    10   08    09
14.44
1993      05     02    17    58   23
40.12
4.7
14.58
1993      05     02    21     34    17
40.10
4.8
14.45
1993      05    03     12    37    38
39.77
4.6
14.39
1993      05    04   06     47    54
40.13
4.6
15.19
1993      05    05     16   46    08
39.90
4.1
14.56
1993      05    05     18    06   51
40.17
4.5
14.35
1993      05    06     01    21    32
40.08
4.9
14.94
40.43
4.41993
1993
1993
1993
1993
1993
1993
1993
1993
1993
1994
1994
1994
1994
1994
1995
1995
1995
1996
1996
1996
1996
1996
1996
1996
1996
1996
1996 
1996
1996
1997
1997
1997
1997
1997
1997
1998
1999
1999
1999
1999
1999
1999
05    06
05    08
05     10
05     11
05    13
20 35 55
22 40 53
10 54 59
03 44 10
18 20 49
14.40
40.13
5.3
15.20
39.92
4.1
14.45
40.19
5.4
14.52
40.24
4.8
14.40
40.19
5.3
05     14    05     01     44
14.49
40.02
3.5
05     18    09     33     13
14.39
40.22
5.0
09     18    04     15    37
5.35
37.56
5.2
09 21 19 11 35
12 04 18 45 15
11.46
39.64
5.7
5.47
32.09
4.2
01    26    02     26     00
5.31
37.41
4.9
05    11    10    08     04
15.75
41.38
4.5
06    21    02     12    21
15.49
41.62
4.8
08    07     14    14    22
13.33
39.66
4.9
08    22     19    56     50
4.53
35.03
4.7
01    20    07     14    27
7.16
38.44
5.0
04    23    20     14    49
12.17
41.61
4.2
09     10    12    30     59
15.61
39.40
4.5
02    20    08     36    46
15.77
39.21
4.5
04    16    12    32    48
15.76
39.37
3.9
05    01     11    45     20
15.45
41.99
4.3
05    05    20    42      17
15.46
41.92
4.4
09     18    23    50     36
12.75
40.51
5.0
10    13   07     35    05
12.84
40.58
4.7
10    16   09    42     49
12.71
40.53
4.6
10    16    18    30    45
12.70
40.54
4.8
10    16    23     18    57
12.73
40.70
3.9
10   17    21    27    54
12.70
40.63
3.9
10   21    03     20     21
12.65
40.45
4.8
12   31     14    27     18
12.12
41.78
3.7
01    03    21    01     29
11.98
41.61
4.5
01    26    06     58     23 
12.06
41.79
4.7
07    13    16    13    08
15.29
41.93
4.2
07    13    18    50     38
15.19
41.99
4.2
07    14    07     15    10
11.94
39.24
3.8
08    17    22    54     15
12.07
39.65
06    30     15    44     28
13.67
39.67
4.8
01    05     18    10    59
5.92
37.22
01    05     18    27    40
6.02
37.51
4.7
01    22    22    48     00
4.92
32.33
4.3
02    08    04    08     29 
11.15
41.87
3.9
02    08    04     54     01
11.16
41.87
3.7
02    08    09     35     53
11.14
41.87
3.5
271999 02 09 15 41 54
1999   06     17  12    34 54 2000   05     10  08    43 31
2000       05 12  17    54 03
2000       05 15  08    33 04
2000   05    16  20    47 51
11.14
41.89
' 3.5
10.78
41.27
4.8
10.22
41.14
4.0
10.00
41.08
4.3
5.62
36.23
4.5
10.09
41.23
4.4
2001  12  05  15  52 37
2002  05  14  18  49 27
2002  08 08  01  50 33
2002  08 08  21  17 11
2002  08 10  12  01 20
12.67
40.53
4.0
12.59
41.13
3.9
14.01
39.94
4.4
13.65
40.00
4.9
13.92
39.90
4.3
2002      08    10   15  56   02 2002      08    10    16   45    56 2002     08    14   20   49    25 2002      08    25   06    12    37 2002      12   01    11    18    32 2003     01    01   23    36    45 2003     06    06    17   31    35
2003     06    10   07    10   38
13.65
39.81
5.7
13.71
39.89
4.6
13.41
39.99
4.4
13.67
39.86
4.3
12.28
39.74
5.1
11.20
41.75
4.6
5.40
32.10
4.6
14.45
40.07
4.6
2003 06 10 18 23 22
2003 08 18 20 07 50
2004    01    18   06   27    00
2004     03   18   22    13   07
2004     04    27   00   58    39
2004     06   11    00    39   44
2004     08   31    23    16   05
2004     10   22    12   00    12
2005     06   04    18   40    35
2005     07    07    16   57    57
2005     07   11    20    36   11
2005     07    18    16   31    42
2005     09   14    15   07    46
2005     09    20   02    17   59
2005 09 20 18 38 28
2005 09 20 21 23 37
2005 09 20 23 27 07
2005 09 21 00 01 43
2005 09 21 04 21 22
2005 09 21 07 12 58
2005     09   21    08   40    03
2005     09   21    10   14   15
2005     09   21     10   30    58
2005 09 21 10 33 01
14.46 40.21 4.3
11.80        41.25      4.0
10.66        39.67      4.6
5.35      32.05      4.6
5.39       37.27      4.1 13.07      39.75       4.5
14.74      39.71       4.2
14.17      40.30        5.5
12.75      40.69       4.5
6.29      37.70       4.7
12.21      40.26       3.7
12.73      40.75       4.5
12.49     40.42       4.7
12.42     40.47       4.8
12.57     40.60       4.4
12.71
12.77
40.53       5.4
12.81
40 29      4.6
40.44      4.4
12.65
12.39
40.43      4.4
12.60
40.50 4.4
13.50
40.44     43
13.19
12.36
40.49 4 2
40.76 4 2 40.38     44
282005
2005
2005
2005
2005
2005
2005
2005
2005
2005
2005
2005
2005 
09  21  11  57 
09  21  13  33 
09  21  14  57 
09  21  16  56 
09  21  18  44
22 
01
26
49 
01
09     21     20     04    52
09     21     21     05 
49
09  21  22  25  59 
09  21  23  36  21
09     21     23     49    10
09    22    01    31    32
09     22     01     39    34
09     22     01     56    46
2005    09    22    03    12    34
2005
09    22    04    15    39
2005  09  22  04  28  18
2005 09  22  05  21  52
2005 09  22  06  08  35 
2005    09    22    07    13    03
2005    09    22    10    14    24
2005    09    22    11    57    43
2005  09  22  12  10  38
2005  09  22  13  58  44
2005  09  22  14  48  17
2005  09  22  15  59  31 
2005    09    22    16    08    08
2005    09    22    17    53    26
2005   09    22    16    08    53
2005 09  22  19  51  52
2005
2005
2005 
2005
2005
2005 
2005 
2005
2005
09  22  22  22  50
09  23  00  55  45
09  23  04  57  51 
09    23    07    06    09
09        23     09     18    31
09    23    09    49    48
09 23  18  01  26
09 23  18  05  07
09  23 20 26 32
12.41 40.42 4.6 12.51 40.51 4.6
12.53          40.47       5.0
11.97          40.24       4.3
12.44          40.39       4.5
12.55          40.50       4.8
12.62 40.66 4.5
12.47        40.45        4.0
11.98         40.32       4.4
12.60         40.42        4.4
12.78         40.44        4.7
12.15 40.46 4.6
12.50 40.64 4.5
12.70         40.46        5.2
12.65         40.49        4.5
12.73        40.51       4.5
12.72         40.34       4.7
12.27 40.42 4.4 12.88 40.37 3.9 12.63 40.50 4.8 12.60 40.52 4.4
12.05        40.41       4.2
12.70         40.55        5.2
13.03         40.75        4.5
12.69         40.38        4.5
12.63         40.40        3.9
12.51        40.33        3.9
12.47  40.34  4.5 12.40 40.44 5.1 12.52 40.49 4.4 12.28 40.47 4.3 12.55 40.60 4.8 12.57 40.59 4.3 12.58 40.54 4.4 12.51 40.60 4.0 12.64 40.49 4.4 12.20 40.25 4.3 12.57 40.47 4.8
29_ CK nlv
.
 1- Catalogue of historical earthquakes in central and cast -***“ M >61 “nd/ °  •—
r
,. . 
1 tiitudes 4.0° - 16.0° north
J2  . 42
» 
Msl
Y.M.D H. MtS LAT LON Mb
Year. Month. Day Hour. Minute. Second Latitude degree north Longitude degree cast
Magnitude
Y
MD
LAT
LON
M
I
1631
03    25
11.3
41.7
9
1842
12   08
9.5
39.8
9
1845
02    12
12.3
39
6'%
1854
02    15
13
39.4
6.3
8
Comment
Dona’Ali,   city   destroyed, casualties
Ankober destroyed Western   Plateau   margin (Appendix 3) Amba Afaji (cracks)
1875
11   02
15.8
38.5
8
Keren, damage
1884
07    20
15.6
39.5
8
Massawa, heavy damage
1906
08   25
8.0
38.5
6.8
9
Ethiopian Rift
(Appendix 5)
1915
09   23
16
38.5
6.8
Nakfa Graben, damage
1921
08   14
15.6
39.5
9
in Asmara
Felt in Massawa
1921
09   21
15.6
38.5
9
Felt in Massawa
1937
11   30
4.9
35.9
6.3
1960
07   14
7.0
38.5
6.3
Chew Bahr Graben Rift floor near Chabbi
1961
06   01
10.6
39.3
6.7
Wollo (see Appendix 4)
1969
03   29
11.9
41.3
6.5
1990
05   20
5.1
32.2
7.2
9
Serdo destroyed. 25
dead)
Southern Sudan, severe
damage
30pgMJlX 3: The E«rth<loake Tremors of >2 February 1845 in the Lake Tana
22*
Ab°uln
12 February 1845. earth tremors were reported throughout western |    region north of Lake Tana to the southernmost provinces. In 
( 1C
Eth ^Pl3the maximum reported intensity was V\ a sign that the tremors were felt Oo °d>r orth in the provinces of Tigray and Eritrea. In the south, the intensity III furthcr Iocajed between the parallels N 5.5° to N 6°, suggesting an approximate
iS(,line | radius of perceptibility of 650- 700 km and a magnitude of the order of 6 '4 ^plCCTiu
.6 fc-
■Ahhadie (1858). Perrcy (1859). Milne (1911). Marinelli and Dainelli (1912),
^ ,19l5).S
.eberg( 932>.
1
Evaluation of the Sources of Information
The original documents relating the seismic events of February 1845 are d Abbadic's
-
accounts incorporated in his field notes. He and his crew were engaged in a geodetic
suney of Ethiopia and on 12 February 1845 they were stationed in Gondar.
Information from other localities was obtained in the course of the team's field work 
Junng the following 2-3 months.
D’Abbadie was a professional earth scientist who also had mastered the language of
the country; we feel confident that he critically evaluated the information received 
before recording it. The same degree of accuracy is not found in the "Earthquake Catalogues” of Milne and Siebcrg relating the same events.
Reports on the Earth Tremors and Location of the Sites
From Gondar (N 12.6°. E 37.8°): Tremors were reported from the different sectors of
the city and a few dry- masonry walls collapsed. The maximum reported intensity is eslimated at V*.
District of Lasta, 100 150 km east of Gondar: The tremors were stronger in Lasta than in Gondar and a village was destroyed by land slides.
Southern Sector of Lake Tana: Tremors were reported in Korata (N 11.6°, E 37.5°).
1 surprisingly not in Bahar Dar barely 25 km away.
From Gojjam: In the region of Meca. near Mt. Kami (N 11.5°, E 37°) the church of
Co ^ ala Meheret was destroyed. As no details are available on the type of
Jistruction and condition of the damage building, a conservative estimate of
was accepierf.
Gond   r    Pans    ^°jJarn>   travelers   reported   that   they   fell  tremors,   not  at   noon  as  in i°                nfound 3pm. If their time estimate is valid, they must have been referring
shock hT Cause<l by an aftershock with an epicenter possibly different from the main the center of Gojjam is about 200 km south of Gondar.
per X)n^ wtral Wo|lo: A report from Ware Haimanot (N 11.3°, E 39.7°) states that 3 Crc trapped in a crevasse and crushed
31From Gudni Region ( N 9.3 . E 36.9 ): I-uirth tremors were felt and thc Q reporting the event used (he expression ’the earth was dancing’, suggest.'0"10 pe’We
experienced long-period seismic effects.
6 n *thailhe)
From Southwest Ethiopia: It was reported to d’Abbadic that the earthquak February were also felt in the region of Ennaria (N 7.8°- 8.5°. E 36 5°1 .< t °f 12 provinces of Kaffa (about N 6- 6.5°).
The locations of the sites mentioned above are indicated by stars on Fig A3 meridional alignment in their geographical distribution comes from thc fact th d'Abbadie only interviewed people along his geodetic survey route C l"aI
Ulc
Estimated Magnitudes
The reported intensities ranged in the north- south direction from V . in . efVcd 12.6 ) to about 111 some 750 km to the south ( N 5 M °), The intensities arc
.  j_j. < f>J
to increase in the direction of the Plateau margin; a landslide and a
th
reported in the vicinity of thc 39 meridian between N 12.5 and N •
32of the magnitude can only be based on the geographical distribution of esli'08^ nsitics antj we consider a magnitude of M = 6 '/< as a good fit to 
^counts. assuming that all the reports refer to a single shock, the main 
d Ahbad'c s
c cmen
|     t of the report from Gojjam is reliable, then one has to admit
shock- .ecnters moved south from Lasta to Wollo. and that the fissunng of the
^agnnude of each of the two shocks would have (ed  Location of the Epicentral Region
that tl* ep’t^
cc | m central Wollo was caused by a mid- afternoon shock. In this case,
to be reduced to about M= 6.
fstimai based on intensity reports and attenuation rates point towards an 
lnKrferei C
| rcgion centered about N 12 *4 °. E 39°. a region covered by deep ravines cpicentra scafpS that cou|d easily be suspected of being scismically active. This
StC<^incaied some 50-60 km west of the Guf Guf marginal graben, which is SZ to have been, and still be. scismically active.
tic location (solid dot. Fig.A3.1) for the epicenters of 1945 would be some 60 J ^nthe east of the location suggested by the reported intensities (open dots). For
accLtput  ivitay.tional purposes, location N 12.2°. E 39.6* has been adopted for the 1845 
334;
 TkeS** Cri* of I**                 *• ShM
, ln r November in 1906. the Province of Shoa was suhjcclefl,
From 25 Aug“ . J ,
s
earthquakes. At‘d
(
SSSiSS--*"*®**            EV
CVCnts rated magnitudes of M = 6.8 .The estimated!^,
maps wcrc givcn ,o N
Maximum intensities in the epicentral area are estimated as hi h
Ababa town experienced significant macroseismic observations 1 *  ‘ Add,,
89
intensities of I = 7.
■ • with cstimated
Addis Ababa
Reports state that the August tremors were exceptionally violent, referring |0 oscillauon of suspended objects, cracking of roofs, doors and windows. A pc
who was silting in a rocking chair in his garden, compared his impressions i0 th 
shocks made by sea waves breaking from time to time on the sides of a vessel aM making it suddenly vibrate. Some church bells started to ring.
The population of Addis Ababa was greatly afraid. Damage, however, was slight because a) the town, being barely 10 years old, had not yet fully developed; and b)the indigenous constructions (the Ethiopian tukuls) could, according to experts, withstud any shock short of a wide rending of the earth directly underneath them. This remark has been made by many observers and was spectacularly confirmed at Kara Kort m 1961.
^^^Zd^X’Xnd Adamitulu
,hC CP,CCn,ral afCa 81 l akC
a ‘,C 8nM,nd mot,on and consequences. At
'
Adamitulu is about I S L
shocks during the afternoon of?5                   Ababa. Personal observations recall five A, utu “dancing" on the south-eastern 906_ObM:rvers describe the nearby Mount
R,ver vcn'cal motions in the surf
a.
* ,ceP banL\ of the river Cnli.m
h °n  ZOn To the south-east along the Bulbula
u
(he can^ Landslides were triggered along the
SSW. indicating therefore that f ° jSl FOSC ’
na r
’ P °gressing towards
r
or NE component.
Lake Langano Lugano (Rg.4) ju binh 
rom Adamitulu. the direction of the epicenter had a N 38.6°) in the northeastern bay of Lake
and the rate of the pulsarinn 0/° 906’ hcighr of the hot water column was 25-30 m 1 c Ua,cr column was ahftiii i m,n A reP°n dated 1926 mentions that the height of
'*Ln°d*r report claims that
P^od of pulsation was about 30 nun
J" onZal 'X J* '"J963 * WK 2-™ I" Augusl 1965 M*rep^ed 
ln 10-15 m in diamer/r V Cn 3 diameter circular pool lying within a circular min cycle of fiiJt Mc^ J,s w«er level fluctuated by 5-10 cm in a complete 9-10 
° ger noticeable
n
F£C 3nd w,thdrawal. In 1970 the surge periodicity no1ApP^**
Seismic Crisis in Wollo 1961
the end of May until September, over 3500 earthauakes of magnitude
]n ]961. fr<*\ Ccnlral Ethiopia. The village of Majete (N 10.5°, E 39.9°) was Ml > 3’5| ^esiroyed; in lhe nearby town of Kara Kore (N 10.5°, E 39.9°) most : omplete'y sCS eollapsed. Cracks, fissures and subsidence of up (o I m deep 
masonO "ou
(hc A(j
s
developed on^
jj  Ababa- Asmara highway; many culverts and retaining walls rc built. Rockslides and landslides were observed on steep
along <he r^[opcs and a 15-20 km long fissure, in places 6-7 m deep, formed in 
^arpmen 
jjgng (foe eastern scarp of the Borkcnna Graben. There were no
n
1 * . four epicenters have been located from telcseismic reports; the
reported was 6.S.
^^maximum damage: Geographically, lhe area of observed maximum damage
Z °s along the Addis Ababa- Asmara highway between latitude N 10° and 11° and was tude E 39 7° and 39.9° At these latitudes highway No I runs along the upper
■  of the eastern escarpment of the Ethiopian Western Plateau, which is dissected longitudinally by the Borkcnna and Robi marginal grabens and transversely by strong XE- SW faulting curving from Afar.
Man-made structures
The village of Majete ( N 10.27°, E 39.56°) was a UNESCO Training Center with single-story houses built of cinder blocks joined by rather poor quality cement; Kara Kore. on the contrary, was an Ethiopian town of crude masonry design ( stones, mud. or poor cement, and thatch roofs) altered with typical Ethiopian tukuls built of clay reinforced with eucalyptus framing. Majete was totally destroyed, whereas in Kara Kore all the masonry houses collapsed while the tukuls withstood the shocks very well.
Along lhe highway lhe damage was spectacular. Large boulders from rockslides, some estimated to 12-15 tonnes, blocked the road. Rubble from landslides covered the pavement in many places. Bridges pillars were fissured and parapets destroyed; cracks 45 wide as 60 cm and as deep as 100-150 cm were opened in lhe road surface, heavy 
s umping and subsistence with a resulting difference of some 100 cm in the surface cv el rendered lhe road impassible.
A *ttr»‘ions in the landscape
Num
j n unco ^
0
and landslides have been mentioned above In addition a scarp
This  J>nso^daled   materials  opened  along  the  escarpment  of  lhe  Borkcnna  graben,
so^e
be followed over 12-15 km until it became obscured by rubble. In
the w S ’ l^c VCrbcal differential displacement reached  2  m. lhe depth  5-7  m. and 
W at the surface ovcrlm
Outside the Epicentral Zone
In C
*ert 3hd Dessie. wme 60 km north of the actual seismic zone, lhe tremors
On
8 « no damage was reported.
b
35In Asseb (N 13.0°. E 42.7°) on the Red Sea shore, tremors of intensity m
Along highway No I from Kara Kore to Addis Ababa strone
No dumagc was observed except in Robi where a tobacco d J treniOrs were and Debre Berhan (N 9.7°. E 39.5°) where a power transfo™?* P'ani de^ from its supporting poles. At the army camp near Debre Be h* Was brought dn supplies were kept out of their shelters for many weeks man‘ Vehic,es and
* crefelt
Boulders were dislodged and rolled down the slopes of volr-m^. t 39.9°) and Boseti Guda (N 8.5°, E 39.5°).
nOCS Fan,a|c (N 9,0». E
At Addis Ababa, some 200 km south of Kara Kore, the first earth tremors were breakfast time On 29 May. many others were felt off and on for at least 2 weeks occurrence was characterized by an abrupt, obvious, and surprising silence from b d and dogs, followed by a wave of rustling noises generated by the twisting of the * % corrugated iron sheets covering most houses. Some masonry structures cracked partition wails in reinforced concrete frame-buildings were dislocated by shearing motion, especially along the Filohawa fault zone in the southern sector of the city. At Africa Hall, a 7-story building still under construction but whose frame-structure was completed, the steel flagpoles on the roof were seen crisscrossing during the tremors
Some inhabitants in Addis Ababa were really frightened. During the night of June I,
all students boarding the University College Arat Kilo campus rushed out of the residences, and students in other boarding schools behaved similarly. The manager of the Ghion Hotel requested his guests to stay indoors; many schools ordered their students to sleep outdoors for a while. So did many families. The Ministry of Education closed the schools for 4 days.
Location of Epicenters
The location of epicenters was carried out on instrumentally recorded data. Thereby 34 epicenters were located by the USCGS, epicenter locations between Dcssic and Debre Berhan. within a distance of about 150 km. The main shock of June 1 was located to N 10.4°, E 39 9°
Frequency. Magnitude and Intensity
From 25 May to the end September 1961. over 3500 shocks were recorded from the ara Kore area. In the first series of earthquakes, which began 29 May. the frequency 
o occurrence reached a maximum of 150 per day; a second series began on June I with a peak frequency of 350 events per day. The shocks prior to June I should be considered as main shocks.
Out of the total of over 3500. two shocks were larger than 6.4 and 7 had a magnitude arger than 5. The area of perceptibility was estimated to about 300 000 km .
lively higher intensities were observed in the southeastern sector of the zf>n^; maximum intensity at the center of the epicentral zone was estimated as V
the modified Mcrcalli scale.Federal Democratic Republic of Ethiopia
Ministry of Water and Energy
World Bank Financed Ethiopian Nile Irrigation and Drainage Project Feasibility Studies of about 80,000 ha net Irrigation and Drainage Schemes
Feasibility Study Final Report
UPPER BELES IRRIGATION & DRAINAGE SCHEME
/SR-D4C: Geology, Hydrogeology and
Geotechnical Report
Part 2 of 3: Annexes E to H
Halcrow
in association with
Generation Integrated Rural Development (GIRD) Consultants
orFederal Democratic Republic of Ethiopia
Ministry of Water and Energy
iVor/d Bank Financed Ethiopian Nile Irrigation and Drainage Project Feasibility Studies of about 80,000 ha net Irrigation and Drainage Schemes Feasibility Study Final Report
UPPER BELES IRRIGATION & DRAINAGE SCHEME
SR-04C: Geology, Hydrogeology and Geotechnical Report
Part 2 of 3: Annexes E to H May 2011
Hxkruw Group Limited and
Geserabcn Integrated Rural Development (GIRD) Qinaultantt
PO Box 102175. Cornel Building (5lh Floor)
GebctMtesse Road Add* Ababa Ethiopia
*215-1 (0)116 63 09 92 Fax *251-1 (0) 116 63 09 91
w **hakrow com
Report has been prepared m accordance with the lrtStnJCllon5 °f
Ummern of Ettaopla. Ministry of Waler and Energy for their sole and
Any other persons who use any Information contained here
nsk
$ Hale
2011 Group Limited and Generation Integrated Rural Development (GIRD) ConsultantsANNEXES
wW iTIH13 M* A****-      IN RE-P--O-—  RT)
I ^r^CTAREA PHOTOGRAPHS_____________________________
J^^maND AREA GEOTECHNICAL PARAMEIER PLOTS PAMSJTE geological mapping oltcrop and joint
nRSERVATION POINTS
1M1NARY SEISMIC HAZARD ASSESSMENT
1—------------ -
"■"
ASHE* C:
a   NF5 D
S1
;
>AKT2°f3
AfjtfEX &
ANNEX Fi_.
. k-i-rV Cl
^SNEX         _
^.KKTNVfTcCAY»41, 7. 1
ANNEX jo_
isA'EX H J.
"^XmSITE DRILLING INVESTIGATION FINAL FACTUAL REPORT, ADDIS r.POSYSTEMS CO LTD, JANUARY 2011
HAM site slake durability photographs
“ham SITE GEOPHYSICAL SURVEY FINAL REPORT. J ANU ARY 2011 ~TRI AL PIT LOGS: DAM SITE AREA
'HUAI. PIT PHOTOGRAPHS: DAM SITE AREA LAB TEST RESULTS FROM DAM SITE TRIAL PITS
part 3 OF J
ANNEX I        RIGHT BANK MAIN CANAL DRILLING INVESTIGATION FACTUAL REPORT ADDIS GEOSYSTEMS CO. L IT). DECEMBER 2009
ANNEX J
ANNEX K.1:
ANNEX K.2:
ANNEXE 1:
RIGI IT BANK WEIR GEOPHYSICAL SURVEY REPORT
TRIAL PIT AND 11AND AUGER LOGS. COMMAND AREA
TRIAL PIT AND HAND AUGER PHOTOGRAPHS: COMMAND AREA
LAB TEST RESULTS FROM TRIAL PITS: STAGE 1 COMMAND AREA
ANNEX LI
IAB TEST RESULTS FROM TRIAL PITS: STAGE 3 COMMAND AREA
ANNEX L3:
ANNEX M:
LAB TEST RESULTS FROM TRIAL PITS: STAGE 4 A 5 COMMAND AREA SOIL HYDRAULIC CONDUCTIVITY MEASUREMENTS
ANNEX N:
tlt GROUNDWATER QUALITY TEST RESULTS
ANNEX O:
ANNEX P
PREVIOUS GROUNDWATER WEI J. COMPLETION REPORTS GUIDELINES FORTESTING AND MONITORING GROUNDWATER WEI .ISDwwto R/r*Mr tf Ertupa, Mt* fry ef
i-TiffpUf /Nur               mJ l>r*9jgf ProfitPn^
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a/Ua^^n^
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^«£PoRTtf Ertt+ia. Aba/ty ^ITjfrrc^ Entr^ >iik Z*n<utf>M a* Drw^t Phjhttfalcrow  Group  Ltd- GIRD Consultants
Nile Irrigation and Drainage Schemes:
Upper Beles Dam
Ground Investigation Factual Report
Addis Ababa
January 2011ITABLE OF CONTENTS
Pages
] jNTRODUnON
1
I j project Back ground
1
I 2 Scope and Objective
2
13 Location and Accessibility
3
2. REGIONAL AND ICOAL GEOLOGY
2.1 Regional Geology
5
2.2 Local Geology
6
3. GEOTECHNICAL INVESTIGATION
7
3.1 Genera’
7
3.2 Field Investigation
8
3.2.1 Core Drilling
8
3.2.2 In-Situ Tests
9
3 J.3 Sampling
10
3.2.4 Folling Head Permeability test
11
3.2.5 Water Pressure Test
13
3.2.6 Piezometer Installation
17
3.2.7 Ground Water Level Measurement
19
3.3 Laboratory 1es*s
4.SUMMARY
5. REFERENCES
APPENDICES
Appendix l. Borehole logs
Appendix 2. Core photos
Appendix 3 In-Silu Tests
3.1  Falling Heod Permeability Test
3.2  Water Pressure Test
33 Piezometer Installation
Appendix 4 Laboratory Test Results
Apendix 5: Pbolos showing mobilization ot and drilling activities
21
29
40tirriorton Drainage Schemes Factual Geotechnical Investigation Report
N,lf *
(Lot 4: Upper Beles Dam)
upper
jjNT«00^'0N
lt proleO fekground
for   Ground   Investigations   at   Upper   Beles   Storage   Dam   for   Nile   irrigation   and A    c°n,raCprojects      wa$    signed    on    8"’    December    2009    between    Halcrow    Group    Ltd    - tjfaioage       |ntegrate(j     Rura|     Development     Consultants(GIRD)     and     Addis     Geosystems     Co. generat'O     Qjent     j5       the     Ministry     of     Water     Resource     of     the     Federal     Democratic Ud blic of Ethiopia. Halcrow Group Ltd-GIRD is the consultant for the project.
. dam is found in Amhara region. The project area falls in two zones of the
region- ’ne u
—. i _ft side is found in the western Gojam zone, Liben wereda. The right side is 
of the Northern Gonder zone, Shawra wereda. Investigation works at Upper Beles 
^mmence on 15 May 2010 and completed on 20 Dec 2010.
The Geotechnical investigation at Upper Beles  Dam site included core drilling of six boreholes  to a total depth of 178.7 meters  (four along dam axis, one at the Saddle and one downstream of dam body), conducting Standard Penetration Test (SPT), water pressure, constant and falling head permeability  test and taking disturbed, small disturbed and undisturbed soil samples, ground water level measurement and laboratory tests  on soil, rock  and water samples. Piezometers  were also installed in boreholes  drilled at the Dam site. Laboratory  tests  were performed at Water Works  Design and Supervision Enterprise laboratory.
This  factual report presents  the results  of the field investigation and laboratory  test results. This  report comprises  main text and appendices  which includes  borehole logs, core photos and laboratory test results.
Addis Geosystems Co.Ltd.
I1.2 Scope and Objective
The scopes of the Ground investigation at Upper Beles Dam p
• Core drilling with rotary core drilling at Upper Bel^ m
the right abutment, 10m downstream of dam body and 35m at the^^ lS**
• Conducting In-situ Tests which includes:                                                                  Saddle o Standard Penetration Tests in soils,
o Falling head permeability tests
o Constant head permeability tests
o Single Packer Test
•    Sampling from boreholes for laboratory testing which includes
o Small disturbed samples
o Undisturbed tube samples
o Ground water samples
•     Ground water measurement in boreholes at the beginning and end of eachM
•     Installation peizometer in borehole drilled at Dam Site and reading of water led during fieldwork period.
•     Conduct laboratory test on soil, rock and water samples in accordance with BS1377 or other approved alternatives.
•     Preparation of factual ground investigation report in hard and soft copy report shall include: Borehole log. Standpipe records, location of boreholes H laboratory test results.
Addis Geosystems Co.Ltd.xjiif Irritation *nd Drainage Schemes Factual Geotechnical Investigation Report
N,lP
(Lot 4: Upper Beks Dam)
! 3 Location and Accessibility 
The proposed Upper Seles dam site is located bn
Mreda town located about 45km from DeurL
toad. Durbete is found at 515km along the mJ
site is accessible through 9km dry weath Ababa'Bahirdar ospha^ coordinates in UTM at the centre of th
^.,o„ ™P P, Uppef 8eles
—
Ms| of Lit*n which •
Durbete /
r °ad Approx^ t
™
3
The
^graphic
3, 270000
,2800°°
1290000
1JOOOOO
Upper Beles Dam Feasibility Study Area
Town
ie Town
YISMALATOWN
Meshenti/fown
Wetet                Town
DURIBI2-
.1 ,'K„
regional and local geology
2.1 Hegi°nal Geo,°gy
«“«** CO the regional geological map o, fmj0 _ « Mod, area comprises from old to youngest..
1596) “» ™««»l geology 0,
geological units are present at Upper Beles irrigation project area.
c gure 2 1 shows re8ional 8e0,°8ical maP of uPP« Be*65 dam site and its 
r
. Alluvium
surroundings.
, Amba Aiba Basalts
• Ashangi Basalts
. Posttectonic granites
*   Termaber Basalts (2)
•    Tsaliet & Tambien Group clastics 
« Undifferentiated Lower Complex
Addis 6eosystems Co.Ltd,
5Legend
Upper Beles Regional Gology
[
Alluvium
Amba Aiba Basalts
Ashangi Basalts
Posttectonic granites Termaber Basalts (2)
Tsaliet & Tambien Group clast/cs | Undrfferentiated Lower Complex
Upper Beles Dam Feasibility Study
Addif
Co. Ltd
Te/ ////««• /•*•». //*»/
*_ »•—**
1 ie*r?****,*r_-
•*«’'*3 ) Sollf and Rocks
So,I and rock units exposed at Upper Beles dam area ar* mainly:.
•     Alluvial and residual soil units
•     Litic Tuff
•     Tertiary Basalt,
Soil units (Alluvial & Residual soil)
The alluvial soil occurs at the flood plain and river beds of RpIp< The Hood pla. a.ong .he d,m e«is con!B.X1XZ “
(0 gravel in composition. The maximum thickness of the <n i abutment as observed in borehole BH UBD 04. The flood^ '* constituted by soft dark grey silty clay with little sand. ” 3t the Saddle is
Rock units
°
day
The dominant rock  unit at Upper Beles  dam site lithic  Tuff which occurs  both at the surface as  well as  at depth as  can be seen in all boreholes  of left bank. At the surface the tuff is  exposed at the left abutment as  observed at BH UBD 01. No tuff was  encountered at boreholes drilled at the right bank.
The basalt at left bank  is  encountered both at the left abutment, BH UBD 01 and at the saddle, BH UBD 07. The maximum thickness  of the basalt encountered is  observed at BH UBD 01 which is 13 05m thick.
Addis Geosystems Co.Ltd,
6DraiMt W*»r"** > Grotrchnlol lnvrmutH fc_
> G£0
.
nO<NKMINVtST)G*T10N
J.1 General
The    *
.  .  lnve$
tiMlton  carried  out  at  Upper  Beles  irrigation  (
an(J       laboratory    testing.    The    field    work    consister
r< kj tfwesK* standard  Penetration  Test, Falling  and  constant i
b^ebdes along  wi^ (e$t and c0|iecting  representative soil, rock am
test, water pcessu 
and peliQmeler insta||atiOn. u
^^rlorming laboratory tests to determine index and enginee.
*** ° oles and chemical quality of groundwater. Methods a, Geotechnical instigation as well as data collected ate describe.
Xs " '** "
in table 3.1.
WtS<“’U°n “'"ed M UPP" 8
Table 3.1 summary  of field geotechnical investigation carried out at L
Project. Description of Reid Investigation
*
OvKrtfOon of
RrtB
Dim Axis
Dowmlfsam
Dim body
5*
BHUBOOl
BH USD 02
OH UBD 04
BH UBO 05
BH UBO 0€
BHU1
I
CxrvOrtfvtg
3170m
SC 00m
30 00m
15 00m
10 00m
35 00
2
Stu TeC
2.1
SFT
•
2
1
2
1
1
U
He»d
^rerxAbi-Ty
its:
•
2
3
1
1
1
2J
Conon     Mead ^er-wxairy
tru
•
•
1
•
1
•
Ww
7
a
•
•
-
5
11
Smpfcr^
11
UrC.ULFtXrtJ
m4
1
1
1
•
-
14
Snul
drnixbtd KW
5
1
3
-
3
3.1
*oOr
•
•
2
■_______
—j
34
Wife*
1
1
-
-
1 __
4
-------- 7"
*
<
imtMiner.
•
•
Add«i Geosystems Co. ltd*.—--.non and DruinJf* Schemas Factual G*o technical Investigation Report
(Lot 4. Upper Heki Dam)
p Jcar«Dr,'"n<
drilling    was    performed    with    a    skid    mounted    core    drilling    rig    fitted    with    water notify    C°JeappfOprjate    core    sampling    tools.    Water    was    used    when    drilling    in    fresh    rocks ^^ppandapP     ^aterja(        T2-86     type     double     tube     Core     barrel     giving     86mm     hole     and 3Cd       meter    core    was    used    for    drilling    in    soft    and    hard    formation.    Temporary    casing ^'used     to     prevent     caving     of     soft     materials     and     rock     fragments.     Generally,     the * 35          app|,ecJ          'n          the          'nvestl8ation          were          incornP,|ance       with       the          British       Standards       for ^ €th0<Materials (BS 5930) for site investigation. Figure 3.1 shows picture of core drilling
X^n at Upper Beles.
joon    as    cores    were    removed    from    core    barrels    the    retrieved    core    samples    were placed    in    standard    partitioned    wooden    boxes    and    logged    and    color    photographed.    Color photos    showing    core    samples    in    core    boxes    are    shown    in    appendix    2.    Borehole    logs lowing    coordinates    and    elevation    of    boreholes,    description    of    soil    and    rock    strata,    SPT- M   values,   run   length,   TCR   and   RQD   values.   Ground   water   level   (if   any),   sample   type   and sampling   depth   are   shown   in   appendix   1.   Table   3.2   Summarizes   location   coordinates   and
depth of boreholes drilling at Upper Beles.
[A DAM AXIS
Coordinates ,UTM
Ma
BH-iD
She
X
Y
Z
Orientation
Depth(m)
1
BHUBD01
Left abutment
261217
1293594
1364
Vertical
38.70
2
BHU80 02
Dam axis Centre
261090
1293700
1333
Vertical
50 00
3
BHUB0 04
Right abutment
260860
1293860
1370
Vertical
30 00
4
BHUB0 05
Right abutment
260685
1293995
1386
vertical
1500
TOT Al-DAM SITE
133.7
stream Dim Body
1
8HU8OO6
Downstream Dam
Body
1293700
261090
1333
Vertical
10.00
[tSadf
fie
l_J_
JH UBO 07
Saddle
1293420
261600
1419
Vertical
35.00
------- totai- dam axis
133.7
--------- TOTAI depth
178.7
fabfp 3 2 i
Project Oca,ion» coordinates and depth of boreholes drilled at Upper Beles Dam
and rock sa >
^ineer mp'es were collected for laboratory test as instructed by the supervising
**ginnm S,gnec* *be Client. Water level in boreholes was measured every day before 8 and end of each shift.
Addis Geosystems Co.Ltd,
8sW
ScKf-ne* Fa luato^^
|l<* • l*ppe* Rrlrt him)
3.1 Picture showing Core drilling at Upper Beles .
3 2.2 Standard Penetration Test
Standard Penetration Test (SPT) was conducted in accordance with test proc*\ described in test No. 19 of BS 1377. The standard SPT equipment consists automatic trip hammer, weighing 63.5 kg with a freely failing height of 760 m frictionless guide rod and split spoon sampler. Blow counts for a total penet^ Jhe
of 4S0 mm from the bottom of a cleaned borehole were recorded and C0Uf,^tfjbuie<j by 150 mm penetration were discarded since the ground is considered to ^eretM drilling activity prior to the test. SPT N-values for the last 300 mm penetrario recorded al the corresponding depths on the borehole log sheetS^p te5t 001
I
performed in five of the borehole holes drilled along the dam site
jpTN-* ^
1
performed in BH UBD 01 as rock formation was encountered at the su are shown in borehole logs where SPT test were performed.
Adcfrs Geosystems Co.Ltd,, Irr-jQcn and PrJ»nj<r Srh#rr-*t Faciual Onttrhmol lnv»iU<jfk?n Report
,NU*
(Lot ♦ Upper Beki Dam)
j2
a
r ^ntY (0U
llnt (Soil, Rock and Groundwater) j$ rnpl'"« *’
1
from dv
disturbed and four undisturbed soil (Shelby) samples and thirteen rock 
boreholes were collected for laboratory determination of index and
,c
properties. In addition four ground water samples from boreholes at dam
efgi
f<enng
□ saddleSHc
collected for PH, Sulphate and TDS determination. Summary of
3 (i details (Depth, sample type and description) is shown in Table 3.4.1, 2 and 3.
TatJ le3 41 Summary
of Soil sampling details in Upper Beles Boreholes.
—
SM^kiO
Sample Depth
Sample Type
(OnmaN
disturbed.
Us Undisturbed)
Sample
Reference
Number
Sample Description
0.60-0.80
D
Sandy CLAY
2.50-2.80
D
Sandy CLAY
BH UBD 02
4.00-4.45
D
Silty Sandy Gravel
100-120
U
Sandy CLAY
1.702.00
D
Clayey SILT
4.50-5.00
D
Sand
irfBark
8H UBD 06
800900
0
Silty Sandy Gravel
1 00-1.20
U
Oayey SILT
340-3 85
U
2803.45
0
BH UBO 07
4 60-4.80
D
1.20-1.45
U
0.3-1.00
D
1
Cobh/ GRAVEL
100-4 00
D
2
Cobly GRAVEL
6.30-7.00
0
3
Clayey Silt Sandy GRAVEI
900-950
D
4
Silty CLAY
13.00-1400
D
2
Silty CLAY
BHUBD04
1780-18.25
D
Silty SAND
21.3022.30
0
Cobly GRAVEL
26.20-26.60
*«ht&»nk
D
Silty SAND
29 40-30 00
D
Sandy GRAVEL
1.00-1.45
D
3
Silty CLAY
10.00-10.45
D
4
Silty CLAY
5.40-6.00
0
6
Sandy GRAVEL
6.60-7.00
D
7
Silty SAND
BH UBD OS
8.00-10.00
D
Cobly GRAVEL
1.00-1.45
0
8
Silty GRAVEL
2.90-3.35
D
9
Silty GRAVEL
Addis Geosystems Co.ltd,
10T>We 3 4.2 Sumnurv ol rort w^pling details In Upper Beles B
or ho|
o        es
I*****
CMibakA*
Number
1692 25
1305-1338
BH Core Sample
BH Core Sample
BHUSOOl
BH Core Sample
26 10-26 30
BH Core Sample
33 00-33.20
BH Core Sample
1
BHU8002
6.S1-67S
B.15-B.41
BH Core Sample
BH Core Sample
226S22.9O
BH Core Sample
T
i
8 65-894
BH Core Sample
1
BH 1)80 07
13 10-B 34
BH Core Sample
17.44-17 6S
BH Core Sample
Y
i
12-14
BH Core Sample
fortn Bank BH USD 05
14 4-1SOO
BH Core Sample
1
____
, able 3.U Sumnsn ot«*« lam’hn« dc,ails'" Uppe' Be'K B°,Ch°"!
MdisGeosystemsCo.ltd,l. irrtiMion and DrJlfWfi? Schftnri Factual Qtctechmcal Invitation Report ’ * (Lot 4. tipper fleki Pam/
fifing And coAnd Constant Head Permeability Test
,hiirtv of soils and rocks can be determined by conducting falling head
^situ permeaonny
^rmeabW fp<t in boreholes. Falling head permeability tests determine the percolation
tei
□ hv filling a borehole with water by recording the rate at which it drains 
^te of an area uy
hea(j permeability test is usually performed in soils of medium to low
Permeability*
nient   used   to   carry   out   falling   head   permeability   test   includes   suitable   water opty  deep  meter  to  measure  water  level,  stopwatch  and  borehole  casing.  A  steel
a$jng  which  a  diameter  of  110mm  has  been  installed  into  the  boreholes  was  used  to cany  out  the  test.  The  bottom  of  the  borehole  was  first  cleaned  before  the  test  started. Thecasing  was  then  filled  with  water  before  measuring  started.  Using  a  deep meter, the drop in water level in the casing was measured at regular time interval for more than one hour.   Falling   head   permeability   test   data   sheet   showing   raw   data   and   calculated permeability values is shown in Appendix 3.a
Permeability value (K) was then computed using Hvorslev's formula for falling head test shown below (BS 5930:1981, code of practice for the site investigations).
O< col
K-A/F (tj-ti) Ln(hl/h2),
F~2nL/Ln l/L/D) +
+ (L/Dp)/
Where:
K: Permeability of sail or rock
A: Cross-sectional area
of the borehole
casing/stand pipe
F: Intake factor
hl, ti: head (hl) of water at time ti
h2, h: head fh2) of water at time h
L: Test section length
D: Diameter of casing/stand pipe
Figure 3.2 Falling Head Permeability Test
Apparatus
Falling head permeability test was performed in
Addis Geosystems Co.Ltd,
12M»
*♦*"*« I Kiual Uxarchrur,,
riz* a ih«o.<iuu.h
• ,'rnrrtti
,11 ft* borrhofci drflliof ak>ng upper Belos dam axis, at the doWl
and at the w<M'< No Wlin« head permeability was performed at bh “*"*
was encountered at the surface. The total number of falling head °* performed at upper Boles is ten. Test depths and permeability (k) JT"'*”*'’1 table 3.5 Data sheet showing details of the test with raw data
shown in appendix 3.a.
Table 35 Summary of Falling head data
** nd calculate.
- J*n^
n
NO.
Test
No.
BHD«Jrwtion
Depth (m)
Total
Depth(m)
fathead
K* cm/sec
1
1
BH UBO 02
50 00
0.00-2 00
3 25695SE-O3 to g 281
2
2
2.00-4 45
1 109031£-03~W2«Si^-
3
1
0 00-2 00
1 492952E-O3 to 0 OOOOOCCmXi
4
2
BHUB004
30.00
5.50-7.50
7 891345E-04 to 4.4S9944uT'
S
3
18 80-2150
3.552512E-O6 to 3.5MSSS(€5
6
1
0.00 3.35
4 11614OE-O6 to 0 OOOOOOCHX
7
2
BH UBO OS
15 00
6.50-8.00
3.524924E 06 to3ll38WE«
8
8.00-10.00
9.839187E 06 to 4 SO312K«
9
1
BH UBO 06
10.00
0 00-2 00
7 891345EO4 to 2.622517E-G2
10
1
BH UBO 07
35.00
4.00-5 85
5.576918EO3 to 1.6S4W3E-03
Table 3.S Test depths and computed permeability (k) values
3.2.4.2 Constant Head Permeability Test
The method was  developed by  Hvorsle/s  (1934) then for a steady  state, constant head
test in which a flow q is required to maintain a head h: Permeability value (K) computed using this formula for constant head test shown below (BS 5930.198 practice for the site investigations). Test depths and permeability (k) values table 3.6. Data sheet showing details of the test with raw data and calcu shown in appendix 3.a.
,
i ted k /a*ue D
Addis Geosystems Co-Ud,**Fb
K, Permeability of soil or rock
q,rate of flow
f, shape factor
h, head
Constant head permeability test was performed in
upper Beles dam axis, and at the downstream of Dam body. ° **
Tible 3 6 Summary of Constant head data
.
NO.
Test
No.
BH Desitnation
Depth (m)
Total
Depth(m)
Constant head Average
K, cm/$ec
1
1
BHUBDCM
30.00
15.00-18.80
2.7766O3E-O3
2
1
BH UBD 06
10.00
3.00-4.00
7.1O1832E-O3
Addis Geosystems Co.Ltd,
14**              .nJ 0.
1M|T
S< Wnx-. I         f
3.2.5 Water Pressure Test
Water pressure or Packer or lugeon (lugeon 1933) test
appall perme*b»l«ty of a rock stratum and get information'5 C°nduc,ed to . in seepage study or qualitative measure of the grouting re 00 S°Und^ss or strengthening of the rock. Il involves the measurement^'irnpe^ab2> can escape from an uncased section of borehole in a given t * V0,Un,e of *a The pressure rs applied from a mud pump as used for core 2?"^ 9 water is measured by a flow meter.
The test procedure followed In conducting this test was
5930:1981.    Below    are    procedures    and    equipment    used    in test at Upper Beles.
Test Procedure
c The test procedure is that followed for single packer test
'* **
'”'n8- The rato
,eo,nowtf
generally as described in $ carrying out water preset
o Test performed after drilling was stopped over the lowest 5m of borehole depth
o Pnorto the test, the drill holes was flushed for at least 15 minutes by a strong flow of
clean water in order to remove all remaining drill cuttings from the borehole walls 
and bottom
o Then natural ground level measured 30 minutes later
o  The  test  was  carried  out  by  lowering  a  single  packer  to  the  bottom  of  the  borehole (to    the    required    depth),    inflating   the   packer   using   gas   pressure   supplied   from Nitrogen bottle
Packer and Borehole characteristics
o Single pneumatic packer inflated using gas pressure supplied from Nitrogen bott o Packer length: gland lengh = lm, total length = 1.40m
o Packer diameter: 76mm-116mm
o Bore hole diameter: 86mm (Drilled by T6-86 drill bit)
o  The  packers  are  supported  on  drill  roads  which  are  also  used  to  supply pressure to the test section
o Water Pressure: comes from piston flush/mud pump
j(ef
Addis Geosystems Co.Ltd,fok rmpt
and Pritrufr ScMnwi FjcIujI Ocfrchmcal rmrrwgMinn Report
___________________________
(uU P
-
rf
rrangement (toward* upstream from borehole):
-,..op is mounted on the water pipe leading to the packer immediately pressure 5® &
uc
0
T”e     p      .    ore      hole    collar    in    a    height    and    position    convenient    for    observation    and
o ntopo,thcD°
c
0
rtcordW    |    upstream,    toward    the    water    pump,    follows    the    flow    recorder    or    flow Itnrn^o
rr,etCr i k  naw with valve, installed between pump and flow recorder, allows  the
* control Dy P
di5
0
0
control and adjustment of the how and pressure
The pump (piston) located so that there is a clear sight to the flow meter.
• nf sufficient volume to provide clear water, free of sediment and suspended A ba$‘n
matter
Test Pressure
test    was    performed    in    cycles    of    increasing    and    decreasing    pressure    steps,    the pressure  level  increasing  with  depth.  The  test  pressure  is  measured  by  a  pressure  gauge mounted  on  the  water  pipe  leading  to  the  packer.  At  each  pressure  stage,  the  pressure  is held constant and the volume measured over a period of 5minutes.
Pressure   sequences   in   the   boreholes   where   packer   tests   conducted   are   shown   in   table 3.S below.
Addis Geosystems Co.Ltd,
16*•» hnnonr •MPr.l’Mje
rxtu*:                    ,,
H-!« I'fTii Mr H
t   ami
j.
Trrt No
Test 5ect*on(m) Pressure (bar)                  ——
—
1
2 20 lo 7.20
08 10-1610^8 -________________________ |
2
7.2010 12.20
0.8-1.6-2.8-1.60 8 ' ------------------ ------------ -
3
12 20 to 17.20
0 7-1.4-2.0-14-0.7                  - -------—.—__
PHliK'Ol
4
17 20 to 22 20
2.54 0 5 5 4 0-2.5 ------------------------- ------------
5
22 20 to 27.20
2 54 0-6 34.0 2.5----------------- ------- -------- _
6
27.20 to 32.2
2-8-5.0-7.B^S.O-ZS — — ■ —.
7
32.2 to 37 5
2.8-6 0-8.8-6.0-2.8~ ----------------------------- __
1
10.00 to 15.00
1-4 2.5 3.5-23-1.4               ~                       -..4
2
15 00 to 20.00
1.6 3 043-3.0-1.6                -- -------------- —____
3
20.00 to 25.00
2.5-4.0-5.84.0-23                        ------ ---------- —
4
25 00 to 30.00
8MU8D02
2.84.0-6.34.0-2.8              ~------------- -------- ----- -
5
30 00 to 35.00
2.84.5-7 343-2.6                       ~------------------ —
6
35 00 to 40 00
2.8-6,0-8 8-6 0-2 8 --------------------------------- -----
7
40.00 to 45 00
2 8-6.5-9.5 6.5-2 8                                    ——
8
45.00 lo 50 00
2.8-7.0-10.0-7.0-2.8
-
1
10 00 10 15.00
14-2.5-3.5-2.5-1.4
------
2
15 00 to 20 00
l»6-3.0*4.5-3.0-l 6
BH UB0 07
3
20.00 to 25.00
2.54.0-5 84.0 2.5
4
25.00 to 30 00
2 84.5-7.34 5-2.8
_____________
S
30.00 to 35.00
2.8-5 5-8 3-5 5-2 8
Table 3.6. Pressure sequence during packer test in Upper Beles.
Data recording and interpretation
Field data collection during the tests involves recording gauge pressure, time elapsed and
flow rates. The data collected during the test will then be recorded on another fom
similarly to the one attached in appendix 3.b which enable the permeability to
computed.
a    Permeability   of   l   lug   /   exP essed   in   terms   of   lugeon   units   (   a   rock   is   said   to
r
•ength   of   borehole   accepts   in'   Un<^er    3    head   above   ground   water   level   of   100m,   a   lm
Permeability of iQ.?
water Per minute) (1 lugeon unit is app. Equal to
efficients of permeability and Lugeon unit are calculated by the following formula Usmg a formula from BS 5930.1981, code of practice for the site investigations Coefficient of permeability
K=((q*10’)/(2 * L • H)) * sinh 1 L And
K=((q*103 )/(2 • L * H* 60r» • In L
for 10 > L > r for 10 > L > r
Addis Geosystems Co.Ltd,X lk lcrtPl,on
r _ and Drainjf* Sch*mri Fxtuul OofjchnJcil InvvffigMton Report
(Lot 4: Up
~ ueui Dam)
r
6
iu* °
en
uniting
• 10 )/d * H)
rt nef« coefficient of permeability (cm/sec)
K
lu = Lugeon unit
q s injection rate (litre/min)
L = Length oftest section (cm)
r - Radius of hole (cm)
K = Water pressure in head (cm)
H- A + B + C-Hf
A = Pumping head (cm)
B = Static water head from the middle part of test section up to the
hole.  If  ground  level  is  higher  than  the  middle  part  of  test  section,  this  is the head from water level to the top of hole (cm)
C = Height of water pressure gauge from the top of hole (cm)
Hf = Friction loss of energy in the injection pipe (cm)
Twenty  Water  pressure  (Lugeon)  Tests  were  performed  in  three  of  the  boreholes  drilled along  Upper  Beles  dam  axis.  Location  of  the  boreholes,  test  section  and  calculated Lugeon  Values  are  summarized  in  table  3.7  below.  Details  of  the  test  including  raw  data and  calculated  Lugeon  Value  are  shown  in  appendix  3.b.  Water  pressure  test  report showing  lugeon  pattern  showing  type  of  flow  and  total  pressure-Lugeon  value  curve  is shown in appendix 3.b.
Addis Geosystems Co.Ltd,
18n^r S.hr-r*. I>.!«>!
(U« 4 Vrcrr Orfe* tum)
Orpin
Total (ml
^20 io 7.7iT
7 ’20l° 12 20
12 20 to 17.20
Hit IW01
[U-fl ANstrmrnt)
27.20 to 32.2
BH UBD 02
fDam Ads Center)
BH UBD 07
(Saddle)
>  0  00  to  15.00
1   5.00   to   20.00
20   00   to   25.00
25.00 to 30 00
30.00     to     35.00
35.00 to 40.00
40.00     to     45.00
45.00 to 50.00
10.00 to 15 00
15.00 to 20.00
20.00 to 25.00
25.00 to 30 00
30.00 to 35.00
Table   3.7   Test   section   and   Lugeon   value   obtained   from   packer   test   conducted   i boreholes drilled along Upper Beles dam axis and saddle.
Addis Geosystems Co.Ltd,.                 and Drairur Schnrwj Fxfu.il Oefrtrhruc.il InvrWgjcxn Rrpcri
Nl Wlrrtp<W>'
(Ux 4: Upper Belo Dan)
af e    installed     in     boreholes     for     groundwater     observation     purpose.     Water
M ^n*tert
.   cx S
j ting   at   a   point   or   over   a   nominated   interval   in   a   saturated   material
prt$SU,eC°lred by installing piezometers in boreholes.
ci n b* mea
f piezometer installed at Upper Beles is standpipe type. A rigid, collar jointed 1 ..,»d 3t piezometer. The collar jointed PVC pipe was glued to each
, pyC P‘Pe u
»
dunng I’*
01                   . ipvel of the Static Water Level or water bearing zone in the boreholes.
**orn up lnt itvc
* tail of piezometer insallation is shown in Appendix 3.c
nd procedure of piezometer installation is described below.
Detail a
. Borehole is drilled to its final depth
« Drill rods are withdrawn
, Bore hold is backfilled to the required completion depth with alternative layers of gravel and cement.
. About 30cm thick gravel is placed at the completion depth to form a base and for the piezometer to land
•   The rigid 1 K 'uPVC pipe is installed, the collar joints glued.
•   The uPVC pipe is partly slotted in proportion to the thickness of water bearing zone encountered in the borehole.
•   The slotted section of the piezometer is packed with find to medium size river gravel.
•   30 to 60cm thick fine sand is placed above the gravel layer to ensure water tightness above the slotted portion.
•   The remaining section of the hole is backfilled with alternating layers of gravel and cement slurry.
installation. The uPVC piezometer was being perforated towards the
Piezometer   installation   is   completed   by   making   a   collar   to   provide   protection. Depth of piezometer and borehole number is finally written over the collar.
Addis Geosystems Co.Ltd,
20» nfl W •nW\ * t
IwfrUUm)
™
^.C installed ‘ntwo °’|he boreho,es dr'"pd at the c Sundp-i* plC:Orn*le<Ldv one at the saddle. Designation and Location ol |
, rat.n»4 '"h0"n “ uWe 38 be,°"
BHOe*>t’utton
BHU80 01
BH UB0 02
&H UB006
BMUBO 07
location
left
Abutment
Darn axis
I Centre _
I downstream
dam body
I saddle
Df'pth
Total (m)
38.70
50.00
1000
35.00
Table 18. Borehole designation
and location of Standpipe piezometers
A.dd»s GeosY'tems CoLtd'M U.
Ofiirwgr Schamet Factual GvoUcfinkil Imrviflipticn Report (Lot 4: Upper Betel Dim •
lev^l measurement in boreholes drilling along Upper Beles Dam Axis was basis using a deep meter. Daily ground water level measurement was 
r.^e 127 Aug 2010 the final date the last crew left Upper Beles. u un u grOund water level measurements are shown in tables 3.9.
GW Level. m
GW Level, m
Dare
3-Aug 10
RH No
Mommi
13.8
Evening
13 94
Date
3-Aug 10
Morning
4.2
Evening
28
4-Aug 10
12.63
12.41
4-Aug-10
5.3
2.61
5-Aug 10
14.1
14.15
5-Aug-10
5.72
3.8
6-Aug 10
13.75
13.78
6-Aug 10
12.6
12.55
7-AuglO
13.8
13.93
7-Aug-10
12.6
12.56
8-Aug 10
13.9
12.6
8-Aug-10
12.14
12.23
9-Aug-10
12.94
13.5
10-Aug-10
13.5
13.45
ll-Aug-10
13.4
13.4
12-Aug-10
13.35
13.36
13-Augl0
13.37
13.37
14-Aug-10
13.38
13.38
BHCBD01
15-Aug 10
13.37
13.36
BH UBD 07
16-Aug-10
13.5
12.95
17-Aug 10
12.8
12.7
18-Aug 10
13.5
13.94
19-Aug 10
13.5
13.45
20-Aug-10
13.8
13.85
2l-Aug-10
13.9
13.95
22-Aug-lO
13.97
14.2
23-Aug-lO
13.9
13.55
24-Aug-lO
12.8
12.7
2S-Aug-10
12.94
12.98
26-Aug-lO
12.97
12.9
jJJ-Augio
12.98
12.93
Addis Geosystems Co.Ud.
22K* kngrtR" fr» ->«r khmwi rM1u»)Oc«r<hnlul lnvrt
OW Uwl.«"
Morning
F.vtning
13JuU0
1.79
1.76
**ni
13-Jul    io
14-)ul-10
175
1.74
14JuI40
15 JullO 16-Ju I-10
1.71
1.73
15- Jul-lo
1.73
1.73
1.73
1.73
16- Jul-io
17Jul10
17- Jul-io
18-Jul-10
2.78
£71
2.46
2.42 2.38
18 Jul-10
19-lul-lO
1.73
19- Jul 10
BH UBDOJ
20-IuUO
21-JuHO
22-JullO
23-Jul-lO
24-JuHO
25-JuHO
26-XjI-IO
27-JuHO
28-JuUO
29-Jul-lO
30-JuUO
31-Jul-lO
1-Aug 10
2-Aug-10
3- Aug-lO
4- AuglO
5-Aug-10
6- Aug-10
7- Aug-10
8- Aug-10
9- Aug-lO
10- Aug IQ
20- Julio
21Jul40
22- JullO
23- JullQ
24- Jul-lQ
25- Jul-10
26- Jul-lO
27- Jul-10
28- Jul-lO
29-Jul-lO
30-Jul-10
31-Jul 10
l-Aug-10
2AuglO
3-Aug-10
4- Aug-10
5- Aug-10
6- Aug-lO
7- Aug-10
8- Aug-lO
11- Aug-lQ
11- Aug-10
12-AuglO
12- AuglO
13 Aug lQ
13- AuglO
14-Aug IQ
15-Aug-10
16-Aug-lO
17-Aug, ip
18-Aug-lQ
18-AUglO
Addis Geosysterrs Co Ltd,Iftfe |mfJ««n
. Dr-airutfe Schemes Factual Geotechnical Investigation Report
f Upper Beks Pam)
GW Level. m
Morning
GW LrrtJ. m
Evening
1.58
L56
1.56
1.57
Oatr
19-Aug-10
Morning
2 52
Evening
2.53
20-Aug 10
2.54
2.54
1.55
22-AuglOI 126
21-Aug-10
2.53
2.55
22-Aug 10
2.53
2.55
23 Aug 10
1.57
1.58
23-Aug-10
2.5
2.53
24- Aug 10
1.54
1.96
25- Aug 10
1.58
1.55
24-Aug 10
2.2
2.2
25-Aug-lO
2.5
2Mug_10
27-Aug 10
1.47
1.51
1.51
1.5
1.54
26-Aug-10
2.6
2.4
27-Aug-lO
2.3
2.4
Table 3 9 Da»Y Groundwater LGVe' RGCOfdS
Addis Geosystems Co.Ltd,
24.
I Gr<*t<shnK>l Irrrrctj
*                (144 • Uiyrr WHw Dim)
jJ       L»bor»W Tr*"
„ ww «•»«" “’"dut'KI °" ”“•rock andMmp'« «"«.«.
« S-ouped l"l° lhe < «ow'n  wte o<i«:
o
8B
T«ts on $o*B (Classification tests. Chemical tests. Strength tests)
•    Tests on Rocks
•    Water Quality Tests
The laboratory tests were performed at the Water Works Design Enterprise
Transport Construction Design Share Co. laboratories. The standards and procedures followed in conducting the various types of laboratory tests are described in table 3 u below Copy of laboratory test results as obtained for the laboratories is attached in Appendu 4.
Table 3.11: Standards and Procedures of Laboratory Testing
No.
Test Description
Standard
X
Hydrometer
8S Test 7(B)
2
Atterberglimrt
BS Test 2 (A) &(B)
3
Natural Moisture Content
BS Test 1(A)
4
Unit weight
-
S
Direct Shear
-
6
Free Swell
Gibb & Holtz (1956)$
7s
Swelling Pressure
BS 1377:1975
Table 3.12 summarizes tests requested by Halcrow Group Ltd - GIRD and tests actually performed.
Summary of laboratory test results for the various categories of tests are shown in i following tables.
Table 3.13 Classification tests
Table 3.14 Chemical and Electrochemical Tests Table 3.15 Strength Tests
TaWe 3.16 Test on Rock Samples Table 3.17 Tests on Water Samples
Addis Geosystems Co.Ud,T^ble 3:12 Description and number of laboratory tests Requested end Performed et Lipper Beles Dem end Quarry Sues.
/2
/j?
•• /
L'I
rear        •<»*>>»*»»«
teeerMpry tesww
PiUBOCl         | SMuaooj
5== \
•HUIOM
MUIOQS
■HUIDO*
■h uao or I      Contract I     iMCUttd 1
\
Ofii^f>va
Moisture contents
L2L
J
1
2
2
1
10
9
Liquid hnut.puitM’ limit and plasticity mdea              1
■
J
6
2
J
2
g
17
‘ MJ
Linear shrinkage
1
S
•
1
1
4
7
F1.4
Particle vie distribution by wet sieving
•
•
1
2
•
8
1
FIS
Sedimentalton by hydrometer
2
16
*
2
4
20
Fl.6
Dispersibility by double hydrometer method
3
•
•
3
3
4
9
F1.7
OlspersMty by pinehole Method
-
10
2
4
12
Fl
Cfrmfal Mid dittnKhtmkii
F24
Organic matter content
•
3
•
F2J
Mass loss on ignition
*
3
F2.3
Sulphate content of acid extract from soil
•
4
•
F2.4
Sulphate content of water extract from soil
•
4
3
F25
Sulphate content of groundwater
-
4
•
FZ6
Waler soluble chloride control
•
3
•
F2.7
Acid soluble chloride content
•
3
•
F23
pH of groundwater
-
3
•
F.9
Water Quality Test (Physico-Chemical)
1
•
1
0
1
F9. Includes F2.5 and PH.
ADOIS GEOSYSTEMS Co.LTD.Nile Irrigation and Drainage Schemes Factual geotechnical Investigation Report (Lot 4: Upper Bclcs DamJ
Table 3.12 Description and number of Laboratory tests Requested and Performed at Upper Beles Dam Site
T»»t Description
p M-
•QFvtWWJ
no
Quarry
Sites
Quantity
Remark
F
Laboratory testln<
5H              BH              BH ueoot | UB0 01 | UBO07
BH
UBDOS
UMQ1
UPSQ2
Contract
E wasted
F5 ]          Natural water content of rock sample                              3
JJa-
1------------------------
4
10
FS 2
PoroMy/dmitty    using    sat    ur    a    non    and cahpe* technique*
•
-
4
14
Method not specified
F53
Poroirty/derrMfy       using       taturailon       and buoyancy
1S
J
3
1
1
1
Rate only
0
F5 4
Slake Dur a bit Uy
1
1
4
2
FSS
Soundness by Magnesium sulphate
1
1
2
Sodium sulphate method
F5.6
Aggregate Crushing Value
1
1
4
2
F5.7
Ten Percant Fine
1
1
4
2
FSB [     Aggregate impact Value
-
-
4
0
FS 9         Aggregate Abrasion Value
4
0
F5 10 '       Waler Absorption --------------- r
J
3
3
1
1
4
11
FS 11 I    Uniarml compressive strength
a
3
3
1
3
11
F5 12 | —JI
DeformaMRy {elastic modulus! »n Untoral
compression
2
-
1
♦
2
3
F5 13 .
FS14 j
indirect tensile strength by BratHian test Determinates*    of    point    load    strer^th    of rotk  (1  test  In  the  average  read«r<  From  5
specimen]
-
-
2
0
*
■
6
0
■
FS.15        Petrographic analysis
4
2
FS.16        Petentiat Alcan Wa Reactivity
11
2
| F5.17
1 Dry Density
• BC « t a
•RS 16 6 F5 17 are additional tests
5
3
3
1
11
14                   J3 13 Summary of Laixiiatory ClatsificatKyn les( RoiuBj of So«l Samples from Bumholes
/ **
/ **
/c
c zMn Ur.
M
a
DK^>it>>Wty toy OuAM
”—
MITto
IL
■OTtoLtM
Ft
‘..^ruu« COTtlM Ma
.Mract tram wto                 \ v
(matVD                    \
/
/
I
J
t mm V tM eivxy. \
«• \ \
’
/ 1 1 
1
1
-
---------------- b
WUW0 07                 J         asof          J
1 2 / 1—
——
NO
-\-\
57 65
21 00
-
-
1.0-1 2
NO
583
37 27
21 03
-
JIM
■
•
I          25-2 0            1 -
4.04 45                  30
ND
54 76
35 4-
1931
•
•
1
11 78
25 54
59.7
S»y
•
•
■
■
•
BH ueOCM
03-1.0
12
16 79
640
82 73
Clayey SRy CottFy
GRAVEL
ND-Ptoholel
•
•
■
-
3
1.04 0
90
27.22
14 45
49 33
Cleyey SRy Cottey
GRAVEL
ND^Ptthotel
•
•
•
•
-
544.0
35
092
49 01
30.67
S*y Cette/ GRAVEL
•
•
•
-
-
63-70
20
269
5767
3764
Oe» S4ty Seedy
GRAVEL
O(^nMei
20.35
1720
115
30 55
•
•
9 09 5
JOO
37.66
1149
2065
Grwttty SHy ClA V
N(XPrho*e|
67 9/
20.69
39M
•
20.36
11S-1235
7.0
1742
13 67
6V31
Oeyey S4ty Sandy
GRA/E
74 20
37 23
3702
3318
4224
2107
13014 0
445
5201
149
Cxivttey S*y CLAY
NDt(PlnOtte)
726
38 35
3925
•
20 54
■
1701025
7.0
75.91
1709
•
CoCttey GRAVEL &
GrwtteySANO
ND4(Pei hotel
•
•
•
21 3-223
1.84
1146
230
61 1
Sr^ttey Silty SAX)
*
•
•
•
•
26 2-26 6
55
3266
45 23
1661
CoOttey GRA^L
ND-rPrtt>e:
*
•
•
•
•
29 4-30 0
15.0
36.66
48.14
*
Clayey S*y Sandy
GRAVEL
XJtPrhoie)
•
•
•
1.01 45
40
1132
an
765
CKyey $*y GRAVEL
ND.fPInhttei
20 66
*
BHUBDD5
■
4
23135
95
16.11
10.37
64 02
CoOtteyCleyey Sat,
Sandy GRAVEL
NO^Pnhale)
63 33
3201
31.32
3297
269
3297
060-7.0
044
7.52
3507
56.97
Cobttey GRAVEL
28.72
16 67
9.85
■
ADDIS GEOSYSTEMS Co.LTDNile Irrigation and Drainage Schemes Factual geotechnical Investigation Report
(Lot 4: Upper Bclcs Dam)
16-100
•
•
•
-
UtodkumGrnwl-313%
-
•
-
•
Cm* Or•¥•!-% r»%
*
•
111 2
•
-
•
•
■
NO
5505
XM
2334
■
1 mo
•
•
*
•
•
NO
55 52
Mil
UM
5
BH UB0D6
ura
•
•
-
■
•
NO
34 M
27*4
*
317
4 5-10
BO
1593
noj
■
Sand
•
*
mo
0.0
142
ir
S*r Sane?
*
•
•
■
♦
•
•
-
-
•
•
*
■
12145
•
-
•
•
ND
107J5
4412
35 7
-
(fi ueuQ/
IM 45
-
•
•
•
•
NO
M.M
44 32
4952
17.04
6
4 MB
•
•
•
•
NO
63 JO
30 41
52. B9
J
L J
4nd Drainage Schemes Factual Geotechnical Investigation Report
jlje imP11003
(Lot 4: _Upper IkjciDam)
sumnwv °'
and Bacteriological Water An„|ySrs
_____—------ r '
------- --------
— ——Source Of Sample
WH^OHMOaMxaimxiummum allowable
I
BH UBD02
BHUBD 07
Concentration
(m</l)
Remark
J       ___ ______
226
82
1000
-----------------------
348
118
-
7 36
6 88
6.5-85
-
—
1.97
2.47
-
52.5
9
200
—■----------------
4.3
5.7
-
----------------
i 1 flt/ i^-'----------------------------
76.0
43.7
500
1C
——
19
A Rd
13.68
2 28
200
mn
—■—
0 74
1.95
0.3
•
•
0.1
—------------------
0.91
1 82
0 72
1 82
L5
250
-----------------------------------
0.02
0 69
008
1 87
45
■"l 1 agatney i irw1 t - —-------------------
1
174.8
62.7
-
•
-
1 • .QB""*?  **    •    —------ lmt/1 H COJ
213.26
74.49
-
"j~         (mi/l 50*)                                ——
4.52
8.7
400
“jrTSithJSx'' ?o*)
032
0.3
-
I'gi !#»«/* in</IAJ|
-
-
-
if inflifTf'l0)
0.013
0013
-
T Otlnfl
1.5
2
-
>115. Suirrrary of Rock Strength Tests
’JOS- ’IM
2540857
1567737
’ y«emsC
oL(d
30Nile Irrilltton Jrtd Drainage Schemes Factual Geotechnical (Lot 4; Upper Bcfa Dam)
.
Katior
As part of the feasibility stage design of Upper Beles Dam project g consisting of field geotechnical investigation and laboratory testing e°teChnica Beles Valley at the proposed Dam site and Quarry area.
The field investigation included core drilling of five borehole holes al quarry area , SPT tests , falling head permeability and water pr
* as carriec
a*
piezometer    installation    and    ground    water    measurements    were    n    rf    tests
at dam site.
Depth of boreholes at the dam axis range between 10m and n
Perfo^ed in
ju.um apd or
Borehole  drilling  showed  that  at  the  dam  site  saddle  area,  basaltic  rock layer overly by soils of residual and alluvial origin having various thickness?^ Laboratory tests were performed in soils, rocks and water samples collected fro
The tests include index, chemical and shear strength tests on soils, index a rocks and chemical tests on water samples.
00 Slr
Addis Geosjstems Co Ltd
31rrTl«Don and Drainage Schemes Factual Geotechnical Investigation Report
d institution. Code of Practice for Site Investigation, BS 5930:1981:
j^standar Department of the Interior Bureau of Reclamation, 1998
I *,rth                     at The field description of Engineering Soils and Rocks.
: Afhparn M 1961 General Geology Map of the Blue Nile River Basin, Ethiopia,
ll■
V
h    and    water   resources    of    the    Blue    Nile    Basin.
VJO 000 in land ana
al (Compil ), 1999, Geological Map of Ethiopia 1:2,000,000.
Tefe ’
S'
t ^o*Gorup
... zjion pre-feasibility Study report, Upper Beles Irrigation Project, Addis
’
32Wf
R/frAh- <<Miwfrf tfW’airr aiM Eung DfMft PryiftfAPPENDICES1
»APPENDIX 1
BOREHOLE LOGSI,.a^’kr°'"GrZ
ProjeeC Nile irng«‘>»"
an d Drainage
p21293594
E~26l2i7 ElevaMoo;
Total Depth: 38.7th, Inclination: V,ni„,
Bering Type R?“5'
DRILLING
geological descript^
Below 13.5-13.0n fofter
ut *fc Fr«p'* rti of tuff
r
Jfferentley weather* twf< 70X- transitional tone.
Weak occaWmlly pinkish white
to very
close
very C^yey J5£nItfc TUfT
wotherrt
,
a
less cenented. le**
and           fine           proxied.* Softer soapy textile
00 loneratk:        trac y ^onerfttc
t
HH           borehole
UBB8R
JLS
STORAGE RESERVOIR ROCK SAMPLE
RQD
upper rei.es balancing           CD UNDISTURBED SOIL SAMPLE
KJ DISTURBED soil sample
Bo’Uxr Of Borehole
5 STATIC GROUND WATER LEVEL
rock QUALmr designation
TCR
total CORE RECOVERYrsTEM CO. LTD
fTD-GRttL and Drainage
proieCt Beies Dam Site (Belen)
• lipper
HouryCormt
Borehole No BH UBD01
Sheet 3 of 4
BH Coordinates:
N=1293594
E=261217 Ground Elevation: 1364m. Total Depth: 38.70m Inclination: Vertical
GEOLOGICAL DESCRIPTION
V ‘ V ‘
V   V V
V    V V V
V   V V
V    V V V
V   V V
V   V V
V   V V
V   V V
V    V V
V    V V V
V   V V
V    V V V
V    V V V
V    V V
7*«s5Kf»«
CZ) UNDISTURBED SOIL SAMPLE DISTURBED SOIL SAMPLE
“ Bottom Of Borehole
£ static ground water level
k   RRecov^Y
Logged By: Samson AbebeADDIS GEOSYSTEM CO. LTD
Client: Halcrow Group LTD-GRID
Project: Nile irrigation and Drainage
Project
Site/ Location: Upper Beles Dam Site (Belen) Date Started: 13 Jul 2010.
Date Completed: 26 Jul 2010.
Boring Type: Rotary Coring.
DRILLING
E=2 t’round Ei€ Total Deptl Inc li atiOn
n
J 
5i
X
V
: ft Q
LaJ
S5
Q•a
Jft
z\
X
vz
u
r\
X
xz
Q
a
ft
♦»
C
n
u.
□
L*
f
□
z
GEQLDGICA
->rTc------
31.35
100
958
1
Str ®?0 to wry basalt «itn
or. WJ-7 allohtly operv-tk «‘itK/cUy. v
dot*
3220
100
65.9
1
*
33.70
100
J 36
26.7
4
L 33 5
100
411
9
r
3750
100
33 5
15
]38.70
100
708
5
VV
v
vv
v
vv
v
vv
v
vv VV
VV
v
vv V
VV
v
vv
v
vv
v
vv
v
vv V
V V
V V
v
vv V
Very wtro*Xj da «et4un to widely
•phwnHIC MSAL1 with nlnerela
an BOREHOLE:
UBBSR  UPPER  BELES  RAIANCING STORAGE RESERVOIR
R^>        ROCK SAMPLE
RQD        ROCK QUALITY DESIGNATION TOR TOTAL CORE RECOVERY
□undisturbed soil sample disturbed soil SAMPLE
Bottom Of Borehole
■S static ground water level
Logged Bystem co. ltd
Borehole No. BH UBD 02
Sheet 1 of 5
"jyrD-GRlO
ftn d Drainage
r  Beles Dam Site (Belen)
■VPpe                , A 03 ^n 2»10-
03  2010.
Coring-
BH Coordinates:
N=1293700
E=261090 Ground Elevation: 1333m. Total Depth: 50.00m Inclination: Vertical
GEOLOGICAL description
Very stlFF dark reddish brown stlgh Sandy CLAY with occasionally grovel- bcUder size basalt.
Reddish brown Sandy very Clayey GRAVEL Grovti Is subrounded to rounded Fine tD coarse grained oF basalt
fragnets.
7.4/6J.5A
“*tMQU
‘’■“OU
Sm Nation- \ SEREcOVERY
OUNDISTURBED SOIL SAMPLE DISTURBED SOIL SAMPLE
------ Bottom Of Borehole
■X- STATIC GROUND WATER LEVEL
Logged By: Samnon AbebeADDIS GEOSYSTEM CO. LTD
Client: Halcrow Group LTD-GRID                    ~ ~ ~ ~~~ Project:  Nile  irrigation  and  Drainage
Project
Site/ Location: Upper Beles Dam Site (Belen) Date Started: 03 Jun 2010.
Date Completed: 23 Jun 2010.
Boring Type: Rotary Coring.
DRILLING
^^hoh
BHC
_ Sh, °ord
Na Es
Ground E] Tot al Dept
Inc,inatiOl
GE 0LQg1c
<907.) fe but roc
UA5
13 HO
StrDAg pinki
•Fathered        r tutf.    Lrthic. to  ^eertun  Qr end       tuff(5G Closely    Jolnl COatlnQf.     re redkjr «pac<
RH
UBRSft
RS
RQD
TCR
BOREHOLE
UPPER BELES BALANCING
STORAGE RESERVOIR
rock sample
ROCK   QUALITY   DESIGNATION TOTAL CORR RECOVERY
□□undisturbed soil sample DISTURBED SOIL SAMPLE
~ Bottom Of Borehole
J. STATIC GROUND WATER LEVEL
Loggedstem co. ltd
Borehole No BH UBD 02
Sheet 3 of 5
Cr oUp LTP-C WD ’ ct  Rples D“m Site <Be,en> Upper Bele
.3 Jun 2010
J:  23 J«n 2010’
Coring-
BH Coordinates:
N=1293700
E=261090 Ground Elevation: 1333m. Total Depth: 50.00m Inclination: Vertical
GEOLOGICAL DESCRIPTION
• » • • •
Sane   as   above   but   Fresh   to slightly weathered.
IM 93.3
Sane    os    above    but    neAn    to
widely spaced jointed rtrong.
CZ) UNDISTURBED SOIL SAMPLE
disturbed soil sample
Bottom Of Borehole
h ^'^'JTrr
-¥• STATIC GROUND WATER LEVEL
^^S’ATIOX
H ^0VEry
Logged By; Samson Abebc\DD1S GEOSYSTEM CO. LTD
Client: Halcrow Group LTD-GRID
Project: Nile irrigation and Drainage
Project
Site/ Location: Upper Boles Dam Site (Belen) Date Started: 03 Jun 2010.
Date Completed: 23 Jun 2010. Boring Type: Rotary Coring.
BHCo
G   e=26'«?' 
C ’ro,l"<i EleVati
DRILLING
GE ^DGICAL
33.85
35.00
2121
- 3ML
Strong pinkish orry slightly
■ cothrrfd rhyolitic □gyax’-itt TUFF. LbtWcs art angular fru to nedlun groined d* bawltCNO and -tuffcSOZ) fragnents Closely Jointed tight/healed coatings, rough occatcnaUy nedlun spaced Joints toe’o* *>•
JLfiO
hr
BOREHOLE
UBBSR
ltper bei.es balancinc
storage      ^
c,ng
□undisturbed soil sample
res
K DISTURBED soil sample
RS
hock sample
RQD
—■ - Bottom Of Borehole
S- STATIC GROUND WATER LEVEL
RorK Wautc designation
TCR
lb*1
total core recovery
Logged By:
Su^00■
Group LTD-GRID irrigation and Drainage
ect
;  Upper Beles Dam Site (Belen)
03 Jun 2010.
jeted: 23 Jun 2010.
P ‘ rnlflp
^  Rotary Coring-
Borehole No. BH UBD 02
Sheet 5 of 5
BH Coordinates:
N=1293700
E=261090
Ground Elevation: 1333m. Total Depth: 50.00m Inclination: Vertical
P
f
GEOLOGICAL DESCRIPTION
Strong     light     grey     to     pr*l|h
grey nix
to slightly
wothered fine to neclur\ grained aggioneretlc TUFT rttb (fstinct Ffrw grab-ied horizons. ltthk:s<30X> ba salt (SOX). Pin* tuff Joints clean, tight rough.
BOREHOLE
VPPER BELES BALANCING
STORAGE RESERVOIR
pock sample
"WK QUALITY designation
for AL CORE RECOVERY
□□ UNDISTURBED SOIL SAMPLE
KJ DISTURBED SOIL SAMPLE
------ Bottom Of Borehole
STATIC GROUND WATER LEVEL
Logged By: Samson Abe be■------
ADDIS GEOSYSTEM CO. LTD
nientT HaTcrow Group LTD-GRID
Project: Nile irrigation and Drainage
Project
Site/ Location: Upper Beles Dam Site (Ri ht Bank)
B °reh^N??\^
s»
(
Date Started: 27 Sep 2010.
Date Completed:.
ing Type: Rotary Coring.
G
DRILLING
GrOU”<J Elev Total DeUuePt tuhl3:K3o \ ,nCli««ti»„:Ven
?
—2Zn,cal
1
-
■'<*-txr»ded. Cotobi. ar* >»».ltlc rock
,
Z
l-
1
5. J
J
z.
Grrylsh dark cobbly (JMVEL Gravel fine to -edur.
u
tutxinoulir Cobb** and gravel we basaltic rock frapwnt*
■
Dark arty slightly cobWy MoM'r silty GRAVEL. Grav«* b 6m U coarse subangUarXobM* s"d crave* ©re boaaibc rock fragments.
4
Drok grey flatly
5»AVEU>avei * coarse anaU»r V3 Cobb** ©nd gr©*** tr< rock frapRents
9
»H
LTBBS
BOREHOLE
EHp beles balancing                 LZD undisturbed soil sample STORAGE RESERVOIR                    KJ DISTURBED soil sample
RS
RQD
tcr
Rock sample
r ock quality designation total core recovery
Bottom Of Borehole
■X STATIC GROUND WATER LEVEL
Abfb<Group LTD-Gri
and Drainage
ir ri^tlO° an
Z 7 SeP 201°-
ed:
Rou.ryCoriBfe
Be,eS Dam SUe (BeleD)
Borehole No. BH UBD 04 Sheet 2 of 3
BH Coordinates:
N=1293860
E=260860 Ground Elevation: 1370m. Total Depth: 30.00m Inclination: Vertical
GEOLOGICAL DESCRIPTION
),4/6>J0.K
HrAun <Jm« to dmo« dork
■Ughtly (rovtty Mty CLAY. Grovel la              Fkw grokwd angular bosaltfc rock Fragment.
«
u 
b
m UNDISTURBED soil sample
K DISTURBED SOIL SAMPLE
— ■ Bottom Of Borehole
S- STATIC GROUND WATER LEVEL
" ,ERecovEHY
Logged By: Samson AbebeBorehole N  Ru
o
• „ and Drainfl* v ‘” Nile irritf®00
en, ": f<^’DM,siM
BH Coordinates'
N =129386o
£=260860
Ground ElevatiOn.
1J?|>
Total Depth: JO.OOm Inclination: Vertical
GEOLOGICAL DESCRlP^
Dark 6f<^ oightly Grw  Oty
SAND Grovwl I* Ark <Yw ar^Mr
y
R^JUR t© CCMTW  V^Mr U ^ouncw*         Cow.         pv*         -
b a»oltk rock
Jlty W* Dprk brown ur’’                 to cotTH
_ „ . n - CJJ.VLT
'■
C*Z‘H
Grwv»>
3r<cul*r to
*     *kfUb»rvjl>r       b**“"C
core
Dark
Gr<**< • T Cfltotol*
***
3M 70.5
BH UBBS
RS
RQD
TCR
BOREHOLE
UPPER BELES BALANCING STORAGE RESERVOIR
ROCK SAMPLE
ROCK QUALITY DESIGNATION TOTAL CORE RECOVERY
I I undisturbed soil SAMPLE
£2 DISTURBED SOIL SAMPLE
------Bottom Of Borchok
J STATIC GROUND WATER LEX EL^SYSTEM co. ltd
lto-gkid
and Drainage
g eles Dam Site (Riaht Bank)
Borehole No BH UBD 05 Sheet 1 of 2
BH Coordinates:
N=1293995
E=260685 Ground Elevation: 1386m. Total Depth: 15.00m Inclination: Vertical
GEuLOGICAL description
4J0/9J.IBJ3
?^E
CZ) UNDISTURBED SOIL SAMPLE K DISTURBED SOIL SAMPLE
------Bottom Of Borehole
£ STATIC GROUND WATER LEVEL
s,'.<!1  U
a
t vd Esicn
Logged By: Samson Abebe\DDIS GEOSYSTEM GO. LTD
Cli7ntT HdcVow Group LTD-GRID Project: Nile irrigation and Drainage
Project
Site/ Location: Upper Belea Dam Site (Belen) Date Started: 31 Oct 2010.
Date Completed: 10 Nov 2010 Raring Type: Rotary Coring.
~ 26°6«5
Grou»d El
Total Depth. °n: 1
In V                 ■
Incl,nation:VeM.
DRILLING
ge^icau *
Wii0)
V   V    VV
V   V V
V    V    VV
V   V V
V    V    VV
V   V V
V   -V   V Y
V   V V
V    V V V
V    V V
V    V V V
V    V V
V    V V V
EXT’
IamJ.
T»w
Dark upKoWtic do»rl.
•UaMly wraVwrtd |&<t
Very strong Jokt Krl«e>
yrllowlfth prerrfch gray im
cfarh bro an ftaro.
V   V V
V   V V V
V   V V
"Un k TapcUar to WXIM ;lwl
. to *rry doarljr Jolted
TNtfwrrt MSMT Stror^ vtoW
V rxirtl, rrthikt aaartz WIL-------------------------
BR          BOREHOLE
UBBSR UPPER BELES BALANCING
STORAGE RESERVOIR
RS
ROCK SAMPLE
□ undisturbed son. sample
j^j DISTURBED SOIL SAMPLE
----- BoUono Of Borehole
y STATIC GROUND WATER LEVEL
RQD rock quality designation
TCR       TOTAL CORE RECOVERYstem co. ltd
Group LTD-01110
G n and Drainage
ir ri^t,on 8
.UpPer .
Roles Dam Site (Belen)
’ »^°
:23  Jun 2010.
201
Borehole No BH UBD 06 Sheet 1 of I
BH Coordinates:
N=1293700
£=261090 Ground Elevation: 1333m. Total Depth: 10.00m Inclination: Vertical
Coring-
GEOLOGICAL DESCRIPTION
Stiff dark broen Clayey SAND
aP—
Stiff dark brown Clayey SILT.
Grey Sandy GRAVEL. Gravel If fir* to coarse and autoan^ulor to rounded
Grey Rixtir-e of SAND. »AVEL a^d CDBKL Gravel If fine to coarse ro*x*ded to subrounded With Irttle Ones.
^ehole
*
^PI.E
□ UNDISTURBED SOIL SAMPLE
K DISTURBED SOIL SAMPLE
------ Bottom Of Borehole
-X STATIC GROUND WATER LEVEL
^Designation
Recovery
Logged By: Samson AbebeT^geosystem co. ltd
- Client?Halcrow Group LTD-GRID
Client:
Project: Nile irrigation .nd Dr.m.ge
Project
Site/ Location: Upper Beles Dam Site (Belen) Date Started: 02 Aug 2010.
Date Completed: 07 Aug 2010. BoringT>pe: Rotary Coring.
^hole
——__        Sfoe B » Coo?di
N=i
E=2
Gr «und         El
e
Total Depth Inclination:
drilling
geoldgicai
Stiff    greyish    de soil of high pid!
Stiff dork »ty piostlctty
Dark slightly gr< Grovel *« dork » ar>QJar,
Wratherd bed rc os (r»r oro*Jlr Grovel IS dork gr
to coarse bo sol t co«p‘elrl< TUFF.
0 65 100
I
BH             BOREHOLE
UBBS         UPPER  BELES  BALANCING STORAGE RESERVOIR
RS             ROCK SAMPLE
RQD         ROCK quality DESIGNATION TCR         TOTAL CORE RECOVERY
□undisturbed SOIL SAMPLE
K DISTURBED SOIL SAMPLE
------ Bottom Of Borehole
J. STATIC GROUND WATER LEVELBorebole No. BH UBD 07 Sheet 2 of 4
LTD-GRI*/
Beles Dam Site (Belen)
2010-
‘ o7 Aug 201°
Coring-
BH Coordinates:
N=1293420
E=261600 Ground Elevation: 1419m. Total Depth: 35.00m Inclination: Vertical
GEOLOGICAL DESCRIPTION
GrryWi t** aeoloewra’K/uw Rodrrattly weathered closely touted TUFT. Hoderotely ftrong irtHcf tu€F<2(TO basalt3009 Joints art stained orange brown, rough open to tight.
Strong ba»alt(70X) tuff(3WO
frawntt
brown staged slightly open rouoh SV*SH*<5’
art oron«<
*
*
□ UNDISTURBED SOIL SAMPLE
K~1 DISTURBED SOIL SAMPLE
•-----Bottom Of Borcbok?
£ STATIC GROUND WATER LEVEL
DEs1CKation
Recovery
Logged By: Samson AbebeADDIS GEOSYSTEM CO. LTD
Client Halcrow Group LTD-GRID
Project: Nile irrigation and Drainage
Project
Site/ Location: Upper Beles Dam Site (Belen) Date Started: 13 Jul 2010.
Date Completed: 25 Jul 2010. Boring Ti|pe: Rotary Coring.
^ho
BBC^
N:
E=
Gr °und      £
Tot al      D
ep
DRILLING
Inc linatiQ
gedlog
Strong
24.60
25.00
TUFT at a bp
Dark.       ap/wtfti rtos«ly joint*
30.00
BOREHOLE
UPPER BE1.ES BALANCING storage reservoir
ROCK SAM Pl A
ROCK QUALITY DESIGNATION TOTAL CORE RECOVERY
CDundisturred soil sample K DISTURBED SOIL SAMPLE
---- - BuUcni Of Borchok
5 STATIC GROUND WATER LEVELOSYSTEM CO. LTD
Group LTD-GRID ~ irrigation »nd Drainage
ject
i: Upper Beles Dam Site (Belen)
13 Jul 2010.
ed: 25 Jul 2010.
: Rotary Coring.
-—
Borehole No. BH UBD 07 Sheet 4 of 4
BH Coordinates:
N=1293594
E=261217 Ground Elevation: 1364m. Total Depth: 35.00m Inclination: Vertical
GEOLOGICAL DESCRIPTION
VV
V
V V V
VV
V V
VV
VV
v
vv
VV
v
vv
v
vv
\  Mim
v
'•WhushMAKCING
A «WWWl RESERVOIR
'l v-
DESIGNATION
'WRECOVERV
CZZ)UNDISTURBED SOIL SAMPLE DISTURBED SOIL SAMPLE
—— Bottom Of Borehole
£ STATIC GROUND WATER LEVEL
Logged By: Samson Abebek, fl
’IAPPENDIX 2
CORE PHOTOGRAPHSi
IOhntos: Upper Belcs 1)3 m Si,e (BH UB0 11
_ —~ ~~
Plate 1 0.00-5.00m (Core fiox 1 of 9)
5 00 9 60m (Core Box 2 of 9)V
Plate 4.14.05-20.05m (Core Box 4 of 9)Plate 5. 20.95-25.00m (Core Box 5 of 9)Plate 7 29 67-32 20m (Core Box 7 of 9)Plate 9 38 20-38 70m (Core Box9 of 9)Core box Photos: Upper Belos Dam Site (BH UBD 2)
Plate 1: 0.00 $.10m (Core Box 1 of 10)
• * 10-lO.lSm (Core Box 2 of 10.60)Plate 3:10.60-15.70m (Core Box 3 of 10)
e 4 15.70-20.65m (Core Box 4 of 10)Plate 5: 20 65-2 5.90m (Core Box 5 of 10)
Plate 6 25.90-30 95m (Core Box 6 oflO)Plate 7 30.9S-37 00m (Core Box 7 of 10)Plate 9 42.10 47.05m (Core Box9 of 10)
Plate 10 47 05-50.00m (Core BoxlO of 10)photos: UpP<* Beles Pam Site. Right Bank (BH UBD 4)
r
Plate 1:0.OO-S.OOm (Core Box 1 of 6)Plate 4:14.85-19 80m (Core Box 4 of 6)L
Plate 5:19.80 24.75m (Core Box 5 of 6}
?4 75’30 00m (Core Box 6 of6)Core box Photos; Upper fteles Dam Site. Right Rank (BH UBD 5)
Plate 1 0,00-5.00m (Core Box l of 3)
Plate 2: 5 00-10 00m (Core Box 2 of 3)prate 3:10.00-15.00m (Core Box 3 of 3)Core box Photos: Upper Helps Dam Site (BH UBD 6)
Plate 1: 0.00-5.55m (Core Box 1 of 2)
Plate 1: 5.55-lO.OOm (Core Box 2 of 2)Plate 1: 0.00'5.55m (Core Box 1 of 8)
-              70m (Core Box 2 of 8)Plate 3:10 70 15 00m (Core Box 3 of 8)
Plate 4:15.00-19.50m (Core Box 4 of 8)Plate 5:19.50-24 50m (Core Box 5 of 8)
24 50 *29 SOm (Core Box 6 of 8)Plate 7: 29 SO-34.00m (Core Box 7 of 8)
Plate 8 34.OO-35.OOm (Core Box 8 of 8)GO GO CO O O’ Q
APPENDIX 3
BORE HOLE TESTS
. Falling Permeability Test
. Constant Head Permeability Test
. Water Pressure TestAppendix 3.a: Falling Head Permeability TestSheet 1 of 1
ADDIS GEOSYSTEMS CO. LTD.
rM MNG HEAD /PERCOLATION/ TEST DATA SHEET
.wrCLEHFS PAM GF0T£CHNICAL investigation
£f?w----------
^^ukiiz-ai IMVFCTIGATinM
^rANT ^|CRQW Group Lt(L (GIRO) Consukants,
i^ENAME:BHy8002
yaHONDAM AXIS
p 261090, N= 1293700, Elev.=1333m,
(cm)
BOTTOM OF BOREHOLE(cm):
BOTTOM OF CASING(cm):
_________ TEST LENGTH(cm):i
_________ DIA. OF HOLE(cm):
200
200
8.6
DATE:  3-Jun-10
I El*»*d
Depth (an)
Head
------ TOOT
184.01
"Teo
ns?
Remarks
I Bore hole flushed
and water bailed out
to keep the hole
dean.
ITest section has
been saturated for
30m in.
I Generally test
900
1200
p5o
1800
2100
270
TT3
TO
360
553
40.0
450
47.0
490
51.0
173.0
1773
TUTU
TUTU
164.0
1623
Lnhl/h2
0.083381609
0.021978907
0.028170877
O.O11494379
0.005797118
0.017595/62
0.0179TOJ77
0.012121361
0.012270093
0.012422520
0.031748698
0.01298719b
0.013158085
0013333531
Hydraulic
conductivity (k,
cm/sec)
3  256955E-O3
8.585143E-04
1.100378E-03
4.4898OOE-O4
2".2W302E7W
U746IUEW
T79973IFU3
9.469408E-04
9.58$600t-04
9.704679E-04
6.200652E-03
2.536453E   03
2.569828EO3
2.6O4O94E-O3
section is Firm Brown
Silty CLAY with little
rock fragments.
Fragments are
aphanitic Basalt and
W
533
5S.0
0.013513719
0.013698844
2.639285fO3
angular.
2700
3600
AVRAGf;
2.675441E-03
57~U
60.0
0.011889112
0.021202208
2./I26U1FOT 8.281758E-O3
2J64955E-03
DERIVED FROM BS 5030:1981, CODE OF PRACTICE FOR SHE INVESTIGATIONS |  W.tl))in(hl/h2),
,s
F=2ni
2
An|(UDH\(l^l7OJ ))
?     ^permeability   of   soil/highly   fractured   rock 4’Crosssectional  area  of  bore  hole  casing
intake factor
^'l’he»d(hi| of water at timetl
A2=head(h2) of water at time t2
action length
diameter of casingTest No. 02
ADDIS GEOSYSTEMS CO.LTD
failing head /percolation/ test data SHEFT
PROJECT: UPPER BELES DAM GEOTECHNICAL INVESTIGATION CONTRACTOR: ADDIS GEOSYSTEMS CO- PJ£ CONSULTANT HALCROW Group Ltd , (GIRD) Consultants.
BOREHOLE NAME: BH VBD.02
LOCATION DAM AXIS
E= 261090, Ns 1293700, Elev.=1333m,
BOTTOM OF
Time
Elapsed
(sec)
Depth to Water level (cm)
Depth (cm)
Lnhl/h2
Hydraulic
conductivity (fcr
cm/sec)
0.0
445 0
60
120
180
240
429.0
425   0
420.0'
418.0
0.036617363
0.009367750
0.011834458
2   837213E-04   ’10 ke
«Ptheh^
3384306^04 1
dean.
15.004773279
1 4456TTToT
300
420
540
417   0
414.0
34.0
411 0
0.002395211
0.007220248
0.007272759
~W
780
TO
T.0048780S8
38.0
407.0
0.004901971
900
1200
1500
405.0
400.0
398.0
0.004926118
0.012422520
0.005012542
1800
2100
2400
2700
3000
3600
396.0
394   0
0005037794
0.005063302
392.0
0.005089070
390.0
3880
385.0
0.005115101
0.005141400
0.007762005
AVERAGE:
T254382E-OS
~4.373597E.Q4
4.405406E-04 1
7M4838E-M ■
2.969323E-04
2.9839SOE-O4
1.881206E-03
7 590750E04
7.628991E-O4
7.667619E-O4
7.706640E-04
7      746060E-04
7.785B86E04
2.350881E-03
6.9B9827E-04
teen saturated hr
30min.
IGeneraiiyittt
section is Grey u
coarse gramed
GRAVEL with Mrtui
dense medium tc
coarse grained SAC
towards bottom.
Gravel is rounded u
subrounded.
-
2
FCWWLA DERIVED FROM BS 5930:1981. CODE OF PRACTICE FOR SITE INVESTK3A DONS K’(A/F(t2-tl))ln(hl/h2),
F=2m/Ln((L/D)+^(l+(L/D) )]
Where:- impermeability of soil/highly fractured rock
A=cross$ectional  area  of  bore  hole  casing
F=intake factor
hl,tl-head(hl) of water at time tl
h2,t2=head(h2) of water at time t2
Latest section length
D-diameter of casingSheet 1 of 1
01
ADDIS GEOSYSTEMS CO. LTD.
/percolation/ test data sheet
BOTTOM OF BOREHOtE(cm):
200
^^^^n^dG!RDl_Cor^ltantK
BOTTOM OF CASING(cm):
0
TEST LENGTH(cm):
200
DIA. OF HOLE(cm):
8.6
___________ DATE. Hydraulic
conductivity (k,
cm/sec)
27-Sep-lO
I
I
ZhaCTQ* tfPil
'OffHOltNAME; BH UBQ04
0AM axis
.       1293860, E/ev .1370m
Depth (cmf
Lnhl/h2
0.038221213
0.015707129,
0007947062]
0.008010724
0.000000000
0.0000000001
Remarks
_0
7.5
10.5|
121
13.51
13.5
13.5
2000,
192.5
189.5
188.0
186.5
1.492952E-O3
6.13S335E-O4,
I Bore hole flushed
and water bailed out
to keep the hole
3.1O4188E-O4I    dean.
3.129Q55E-O4
ITest section has
14.5/
15.5
0.005376357
0.005405419
3000
~            15.5/
~ 15.5/
0.000000000
0.000000000
AVERAGE.
0      0000006400  been saturated for
OOOOOOOE+OQ 30min.
O.QOOOOOE+OO to grey graveley SILT
0. OOOOOO E *00with little medium
grained Sand. Gravel
is fresh fine to carse
grained
6.053676E-04
2.1OQO5OE-O3
IGenerally test
2.1114O1E-O3
Jsection is light brown
DERIVED FROM BS 5930:1961, CODE OF PRACTICE FOR SITE INVESTIGATIONS
Ln(hl/h2).
^2niAn|(L/D)«^(l+(L/D> )]
2
*
Impermeability of soil/highty fractured rock
A=cro$ssectional
area
of
bore
hole
casing
^intake factor
h ltl’head(hl) of water at
time tl
h ^t2«head(h2) of water
at time
t2
l twt
'    section lengthTest No. 01
ADDIS GEOSYSTEMS CO.LTD
falling head /percolation/ test data sheet
PROJECT: UPPER BELES DAM GEOTECHNICAL INVESTIGATION CONTRACTOR: ADDIS GEQSYSTEMS CO PIC. CONSULTANT: HALCRQW Group Ltd . (GIRD) Consultants
BOREHOLE NAME: BH UBD04
LOCATION: DAM AXIS
E= 260860. N= 1293860, Elev.=1370m,
- 0rT°^°LB0REH0'i7-
Time
Elapsed
(sec)
Depth to Water level (cm)
OAT?
Depth (cm|
Head
Lnhl/h2
0.0
60
120
180
240
300
360
420
480
540
600
660
720
0
15
37
0.020202707
0030389079
_38
48
58
70
78
88
97
105
Tl?
122
750.0
735.0
713.0
712.0
0.001403509
702 0
0.014144507
692.0
680.01
0.014347448
0.017493157
Hydraulic
conductivity (k,
cm/sec
2-89134SE-Q4
1      187023EO3
>74822236-05
~5.524962E-04
5 6O4232E-O4
—<MJ
and water baUet ox
to keep the ho|e
i cl can.
IlT est section h* i
I been saturated for
6     832972E-O4 130mm.
672.0
662.0
6S3.0
645.0
0011834458
0.01499278? 0.013688427 0.012326812 0.015625318 0.011084832
4.622637E-O4
I’Genera l test
5     8563Q6E-O4 1 section is l<ht flh
5.346813E-O4
4 814955E-O4
Mine to coarser**
JSAND with little
63S.0
6280
620,0
6100
1200
1500
605.0
S75.Q
545.0
1800
2100
2400
2700
3000
3300
521.0
5050
4850
470. j
4S5.q
440.0
0.012820688
0.016260521
0.008230499
0.050858417
0.053584246
0045035753
0.031191612
0.040409538
0.031416196 0032435276
0.033522692
3600
AVERAGE:______________ |
0.022989518
6.1Q3379E-O4 jGravel
4.329827E-O4
5      007867E-04
6.351494E-04
3.214901E-04
9.932860E-03
1.O46523E-Q2
8.795669E-03
6.091851E-03
7.892150E-03
6.135713E-03
6.334744E-O3
6.547121E-03
4.489948E-03
33,.117722664466EE--WO3|
FORMULA    DERIVED    FROM    BS    5930:1981,    CODE    OF    PRACTICE    FOR    SHE    /RVESDCA K=(A/F(t2-tl|) Ln(hl/h2).
Where:- K=permeabllity of soll/highly fractured rock
A=cross$cctional   area   of   bore   hole   casing
F intake factor
hl,tl*head(hl)    of    water    at    time    tl
h2,t2=head(h2) of water at time t2
Latest seaion length
D=diameter of casingSheet 1 of 3
ADDIS GEOSYSTEMS CO. LTD
PATA ?heet
DAM^EQIECHNJCAI INVESTIGAIIQN
^^Ltd^lGlRDl Consultant!
BOTTOM OF BOREHOLE(cm): BOTTOM OF CASING(cm):
TEST    LENGTH|cm): DIA. OF HOLE(cm).
2150
1880
270
86________
OATE: 19-Oa-lO
Lnhl/h2
21490
2132.0
21160
2101 0
2081    0
2067.0
2051.0
0007942111
0,007532992
0.007114092
0.009564874
0006750267
0.007770802
2036.0
2022.0
0.007340380
0.006899978
0.006450035
0.005991031
0.006027140
Hydraulic conduaivity (k,
cm/sec)
3.552512E-O6
3.369513E-O6
3.182138E-06
4.278375E-O6
3.019399E-06
3.475885E-O6
3.283357E-O6
3.Q8636SE-O6
Remarks IBore bole flushed and water bailed out to keep the hole
clean.
ITest section has been saturated for
30min.
IGenerally test seaion is Grey
2009.0
2     88510SE-06  medium to coarse
1997.0
1985.0
1972.0
0006570658
1960.0
0006103783
2.679792E-O6
2.695944E-06
2.939O6OE-O6
2.730226E-O6
1948.0
0006141268
1936.0
0006179216
1904.0
0.0166670S2
1872.0
1841.0
0.0169495S8
0.016698476
1811.0
1782.0
1754.0
1726.0
1698 0
0.016429723
0.016142850
0.015837435
0.016092301
0.016355505
1671.0
0.016028838
2.746993E-O6 2.763968E-O6
3.727S92E-O5
3.79O774E-O5
3.734620E-05
3.674513E-O5
3.610354E-0S 3.542048E-0S 3.599O49E-OS
3.657914E-O5
3.584855E-05
1.566274E-O5
grained GRAVEL. Gravel is agular to subrounded with Dark grey coarse grained SAND.
rr
of soil/high |y fractured rock
^Intak^f^100*13rea °f bore ho,e
aoor
^X;:length ter
h2,2*he*S°fW’terat Umetl
water at time t2
oLgasing[Test No. 01
ADDIS GEOSYSTEMS CO. LTD.
Filing heap /percolation/ test data sheet
PROJECT: UPPER BELES DAM GEOTECHNICAL INVESTIGATION
CONTRACTOR: ADDIS GiQSY$TEM$ CO-PIC. CONSULTANT: HALCRQW Group Ltd t (GIRD) Consultants BOREHOLE NAME: BH UBD05
LOCATION: DAM AXIS
E= 260685, N= 1293995, Elev.*1386m,
BOTTOM of bottom of
test
Time
Elapsed
(sec)
Depth to Water level (cm)
Depth (cm)
Lnhl/h2
00
1__
2
3
4
5
6
11
16
335 0
331  0~
0.012012156
0.003025721
0.003034904
0.001520913 0.001523230 0001525553 0.006125593 0,003076926
Hydraulic
conductivity (k,
cm/sec)
4   116140f-Q6]i
I    036807E-06*
Yq39954E-O61clean.
1
330.0'
329.0'
328.5
t0          k«PtheMe
328.0
327.5
325.5
324.5
,T «st section has
teen saturated i*
(
21
26
31
323.5
323.5
^23.5
0.003086422
0.000000000
0 000000000
5.211630E-07
5.219568E-07
5.227531E-O7
1   049512E-05
5.271767E-06
5.288038E-06
30min.
’.Generally t«t
section is
Silty Sandy GRAVEL
OOOOOOOE+OOGlravel is fine to
O.OOOOOOE+OO
• coarse greanec rc
kubrounded
AVERAGE: 2.469756E-O6 FORMULA DERIVED FROM BS 5930:1981, CODE OF PRACTICE FOR SITE INVESTIGATIONS K=(A/F(t2-tl|) Ln(hl/h2),
1
F=2nLAn|(l/D)+^U(l/D) )]
2
Where:- impermeability of soll/highly fractured rock
A=crosssectional area of bore hole casing
F=intake factor
hl,tl=head(hl) of water at time tl
h2,t2=head(h2) of water at time t2
latest section length
D=diameter of casingSheet 2 of 3
ADDIS GEOSYSTEMS CO. LTD
falling heap/percolation/ test pATMnn.
HNICALlNVESriGATlOl^^^-
BOTTOM OF BOREHOLE(cm):  800
BOTTOM OF CASING(cm):  650
TEST LENGTH(crnji] 150
.= 1386m,
DIA. OF HOLE(cm):
DATE:
8.6________
30-Sep 10
pttS.NtifSSS--------------------—- -^^WateHeveljcmL.
Depth l   )
crn
*------------------- 0
Head
1800.0
Lnhl/h2
Hydraulic
conductivity (k, _______cm/sec)
—                    3
797.0
0.003757049
3.524924E-O6
5.5
794 5
0.003141693
2.947587E-06
Qs
1 T*
-6
794.0
5.906304E-07
7
--------------------- 8
793.0
792.0
_________ 0.001260240
0.001261830
_______ L182377E-O6 1.183869E-06
10
12
788.0
0.005063302
2.375236E-O5
Hr
17
783.0
0.006365394
2.986O58E-O5
L-H—
20
21
779.0
0.005121650
2.402 608E-05
25
25
775.0
0.005148017
2.414976E-05
30
29
771.0
0.005174656
2.427473E-O5
35
33.5
766 5
0.005853675
2.746007E-05
37.5
762.5
0005232190
2.454463E-05
45
41
759.0
0.004600731
2.158240E-05
_______ Remarks Iflore hole flushed and water bailed out to keep the hole
dean.
ITest section has been saturated for
30min.
'Generally test section is Dark brown mixture of SAND and GRAVEL. Gravel is fine and subrounded, Sand is coarse
grained.
50
44
7560
0.003960401
1.857856E-O5
55
46.5
753.5
0.003312358
1.553854E -05
60
47
753.0
0.000663790
3.113894E-06
MEUSE;
1.539444E-0S
l |:                          Ln(hl/h2),
k Wln|(l/oM(U(L/D|>)]
•***’ ^permeability of soll/highly fractured rock
A=cro$ssectional   area   of   bore   hole   casing
^intake factor
^.tlshead(hl) of water at time tl
2 A2»head(h2) of water at time 12
L=t«t section length
Diameter ofTest No 03
ADDIS GEOSYSTEMS CO. LTD FALLING HEAP /PERCOLATION/ TEST DATA SHEET
PROJECT: UPPER BE LES DAM GEOTECHNICAL INVESTIGATION CONTRACTOR: AOOIS GEOSYSTEMS CO. LTD CONSULTANT: HALCRQW Group Ltd , (GIRD) Consultants. BOREHOLE NAME: BH UBDOS
LOCATION: DAM AXIS
E= 260685, N= 1293995, Elev.=1386m,
-----------------
--------------------
Time
Elapsed
(sec)
00
Depth to Water level (cm)
DATE:
Depth (cm) 0
Head
1000 0
Lnhl/h2
Hydraulic T
conductivity (k,
cm/sec)
1
15
985.0
0.015113638
9 839187^06
2
30
970.0
0.015345570
9 990178E^06
3
46
954.0
0.016632400
1 082792^05
4
62
9380
0.016913722
1 101107E-05
5
79
921 0
0.018289913
.
1.19O699E-O5
6
94
906.0
0.016420730
1.O69O12E-O5
7
109
891.0
0.016694879
1.086860E-05
8
123
877.0
0015837435
1.031039E05 j
9
136
864.0
0.014934224
9.722386E-06
10
148
852 0
0.013986242
9.105237E06
IS
217
783.0
0.084453831
2.749031E 04
20
283
717.0
0.088056855
2.866311E04
Remark'
'BoteholeM^'
and water bailed
to keen the
dean,
I'Test settlor h* i been saturated *m
l30min
I IGenerally tert section >s Dart gre,
[medium to course [grained G RAVIL
| Gravel is angular tc (subroundeo
25
348
652.0
0.095031279
3.O93334E-O4
30
408
5920
0 096537927
3.142376EO4
35
463
537.0
0.097508540
3.173970E-04
40
513
4870
0.097733971
3.181308E-04
45
553
447 0
0.085705528
2.789774E-O4
50
595
405.0
0.098671528
3.211826E-O4
55
613
387.0
0.045462374
1.479832E-O4
60
663
337.0
0.138341763
4.503120E-04
AVERAGE:
FORMULA DERIVED FROM BS 5930:1981.
K=(A/F(t2-tl)) Ln(hl/h2),
2
F=2ni/Ln((L/DH^(l*(l/D) )l
Where:- K=permeability of soil/highly fractured rock
A=crosssectional   area   of   bore   hole   casing
F=intake factor
hl,tl=head(hl) of water at time tl h2,t2=head(h2) of water at time t2
latest section length
D-diameter of casing
1.561680E-O4Sheet 1 of 1
ADDIS GEOSYSTEMS CO. LTD.
/PERCOLATION/ TEST DATA SHEET
technical INVESTIGATION
BOTTOM OF BOREHOLE(cm):
200
BOTTOM OF CASING(cm):
0
> LT^AMTBHyBD26
^stream of 03^ Body
TEST LENGTH(cm):
200
DIA. OF HOLE(cm):
8.6
M= 1293640' EleV =1331m’
DATE:
30Jun-10
r-rr^to Water level (cm)_
*^THre
fjpsed                                           Head
Depth (    )
crr>
Lnhl/h2
Hydraulic
conductivity (k,
cm/sec)
Remarks
__ ei,__
0.0__
iTw
240
300
0.0
4.0
6.0
9.0
200.0
196 0
194.0
191.0
189.0
186.0
0.020202707
7.891345E-O4
0.010256500
0.015584731
4.006274E-O4
6.087525E-O4
0.010526413
0.016000341
4.111704E-O4
6.249866E-O4
^600
20.0
180.0
0032789823
6.403988E 03
900
25 0
175.0
0.028170877
5.5O1889E-O3
1200
28.0
172 0
O.O17291497
3.377101E-03
1500
31.0
1690
0.017595762
3.436525E-03
1800
37.0
163.0
0.036148514
7.059955E-03
2100
39.0
161.0
0.012345836
2.411193E-03
2700
46.0
154.0
0 044451763
1.736323E-O2
IBore hole flushed and water bailed out to keep the hole
clean.
ITest section has been saturated for
30m in.
(Generally test section is Stiff dark brown Clayey SAND andStiff dark brown Clayey SILT at the
bottom
3300
56.0
144.0
0.067139303
2.622517E-O2
JJJA6E:
6.152O49E-O3
f cw><af/?a€D/7?Q*/&s5s«z-wr, code of practice for she investtgadons
< ^-tl))i i(hl/h2),
r
jz
permeability of soil /highly fractured rock
*“ ” bo" We c”m8
L=t2dh2,ofwater«tlmet2
length
easin
o o| |Test No 01
ADDIS GEOSYSTEMS CO. LTD
FALLING HEAP /PERCOLATION/ TEST PROJECT upper beies dam geotechnical investigation CONTRACTOR: ADDIS GEOSYSTEMS CO. LTD. CONSULTANT: HALCRQW Group LJdJGIRD) Consultants. BOREHOLE NAME BH UBDQ7
I LOCATION; Saddle
Es %ifiQQ N- 1293420, Elev.=1419m,
Depth to Water level (cm)
BOTTOM OF
Depth |cm)
lnhl/h2
0.129388582
0.089490571
~
0.143919509
‘
0.068641933
"
0.059638266
"
0.042802539
"
Hydraulic
conductivity
cm/sec)
5.576918E-03
3.857231E-031
6.2O3232E-O3
2.958611E-03
2.57O534E-O3
1 844879E-03
tokttpthehae
clean.
'Test sections been saturate
30min.
0.029587957
0.021245109
0.015456258
0.006250020
0.009448889
0.006349228
0009600074
0.009693129
0006514681
0.033225648
0.020478531
0.017391743
0.035718083
0.014652277
0.003696862
0.011173301
0.011299555
0.007604599
0.003824096
0.003838776
1 2753O3E-O31
9.157086E-04
'Generally test
2100
2400
2700
3300
3900
4500
5100
5700
AVERAGE:
--------- £-04 section is So*t pe,
6.661971E-04 Sandy Clayey SILT
2.693889E-O4
4.072669E-04
2.73665OE-O4
4.137833E-04
4.177941E-04
2.807964E-04
7.16O474E-O3
4.413338E-C3
3743102E-03
7.697620E-03
~3.157719E-O3]
7.967124E-O4
4.815926^03
4.870345E-03
'1277741^03
j^266Ef3
T654S93E5I
____________________________________________________*----- FORMULA DERIVED FROM BS 5930:1981, COOE OF PRACTICE FOR & K=(A/f(t2-tmin(hl/h2),
F=2llL/LnI(L/0)+v'(l+(l/D)’)l
Where:- Impermeability of soll/highly fractured rock
A=crosssectional area of bore hole casing Hintake factor
hl,tl=head(hl) of water at time tl h2,t2-head(h2| of water at time 12
L=test section length LD-diameter of casing
——-—Appendix 3b. Constant Head Permeability TestA**'    ’
ADDIS GEOSYBTEMt CO. UTO.
l^^LLSLl------------------------------------------- CONSTANT HEAD PERMEABILITY TEST DATA SHEET
/project. upper beles dam GgortoiNrcAi investigation
-
iniiT .MM- titf rnntrini
CONTRACTOR: APP<5 GLOSVSTEMS CQ UP CONSULTANT HALCROWGrona Ltd . /GIRD] CocioftanU
BOREHOLE NO BH UBD 4
L OCA DON QAM AXIS
f- 260960. N* 1233BbQ. E>ev.«1370m.
1 BOTTOM QT WALHOvEjcr^y IHOVTOM Of CASlNGfcmy
Standing Water Level__________ VEST LtNGTH(cm ____________
t
D1A OF  BOREHOLE Um,
DIR or CASlNG(cm)-.
(
)ATE;
llAOtt 10 1
Time (mknlutei)
Flow meter reading (m3)
Start
Firriih
ria pied
(min)
Volume
w
----------------------------------- -----------------------
Remark
Start
Finish
H
F
Hydraulic conductivity (k cm/sec)
11:10
11 11
1
41.4496
41 4943
44 7
1500
23 65
0.001260042
—
11:11
11 12
1
41 4943
41 5176
23 3
1500
23 65
0 000656801
1500
11:12
11:13
1
41 5176
41 545
27 4
23 65
0.000772375
11:13
11:14
1
41.545
41 5813
36 3
1500
23 65
0.001023256
11:14
11.1S
1
41.5813
41 6218
40.5
1500
23 65
0 001141649
111S
11:20
5
41 6218
41 7965
174 7
1500
23 65
0004924595
11:20
11:25
5
41 7965
42 0512
254.7
1500
23 65
0 007179704
11:25
11:30
5
42.0512
42 2376
186.4
1500
23 65
0 005 254405
■Average
1.7766011-01
FORMULA DERIVED FROM BS Ma 19S1. CODE OF PRACTICE FOR STTE HVESTTGA RONS
K-(Q/F(t2 lim
F-2.7S-D
Where:
K-permeability of soll/hlgnly fractured rock
D-Diameter of bore hole
F> Shape factor
H-Head of water above ao below ttandtog groundwater level_______________________________Tert Ko :
Sb»n l of 1
ADDIS GEOSYSTEMS CO. LTD.
PR  OFF  CT  U»»tR  »f  (f  5  0AM  Of  OTtCHKIGAL  INYFSTIGAKK CONTRACTOR ADO6 Gt QSYVIM5 CQJJP
CONSUL TANT MALCROW                Ltd . (GlRDl COfU^UrU. BORfMOtf NO BH UBD »
I OCA HON QAM AXIS
QNSTANT HEAD PERMEABILITY TEST DATA SHEET
BOTTOM Of QQItfHOUKm) BOTTOM OF CAfrNGtcm): St*n*irg Water L-fyf' ______
TEST i£NG1M(cm>
(MA Of BOREHOU ;rm)
D<A Qt CAS NG (em I
30 Jun 10
Time fmmmfeij
Flow meter reading |m3) |
(lapsed
Remtri
Start
FIMlh
Start
F>rw$h
Volume
flu
M
F                     | Mydraubc Conductivity (h, cm/Kt]
12 11
12.19
2365
0 002283298
1
214201
21436
16
*°
12.19
12:20
2
21.4363
2145:
16.1
KO
23.65
000235377
12.20
12.21
3
0 0036 7864 7
21453
214791
26 1
JOO
23 65
12:21
12 22
4
214291
TOO
21 4854
63
2165
0.000887949
12:22
1223
5
21 4854
0 00222692
21 5012
138
300
23 65
12:23
12:28
10
21 5012
21 5765
75.3
300
23 65
0 010613106
12:28
12:33
IS
21 5765
216541
776
300
23 65
0 01093728
1233
1238
20                     21 6541
21.7291
75
300
23 65                                    0 010570825
12:38
124]
2$                     21.7291
218005
714
300
23.65
0010063425
1
12 43
12 48
30
218OOS
21 J 722
717
300
23 65                                    0 010105708
1248
12:53
35
21.8722
21 9331
60.5
300
23 65
0 00854351
12:33
12:58
40
219331
219935
604
>00
23.6S
0 008513037
12:58
101
«5
219935
22.0532
59 7
300
23.65                                    0.008414376
103
108
*> J
22.0532
22.1125
59 3
300
23 65
0 DM357999
108
1 13
«
22 1125
22 169J
S68
300
23 65                                   0 008005638
>11
1:18
w                     22-169)
223263
57
300
23 65                                   0 00803382/
—L        —Appendix 3.C: Water Pressure Test-1
0. r- *- *f*"IOT
__________ ___
CALCULATION SHEET
- ^^w^essu-e, packer test
"'Relles nwJSrrE PACKER test
U6D2
Test
Depth
[mJ
Frcm
10.W
to
1500
T£m<?
W
10
10
10
10
Gauge Pressure
bars _
14
2.5
35
25
1.4
""waler injected
iinresi
FIOW
Type
Lugeon
Value
value
Approx 
k 
(ui/s)
2.2
135
175
16
0
to
c
E
to
1
1
1
1
1
1
i l.E-07
15,00
Id
20 00
10
10
10
10
10
1.6
3.0
45
30
1.6
3.5
4.6
6.05
12-9
2 15
t-
tn
c
E
1
1
1
1
1
1
1JE-07
,20 00
to
2500
10
10
10
10
10
2.5
40
5.0
4.0
25
0 15
28.35
0
0
0
to 
c
e
3
1
1
1
1
1
1
1 £.07
25.00
to
SO 00
10
w
ID 1
10
ID
2.8
4.0
63
4.0
2.B
297 6
517
347 2
166
72 5
E
o
to
D
20
30
15
0
6
6
6.£-07
-L.JZIJ
w—*
30 00
to
35.00
10
10
to
10
10
2.B
4.5
7.3
45
Z0
279.0
170
3472
219.3
149.
c
3
■P
Z3
20
8
W
w
15
8
a E-02
35.00
to
40.00
10
10
10
10
10
2J
60
9.0
6.0
2.8
0 05
2.9
7,35
2 05
0
k—
ra
c
E
to 
-J
1
1
1
1
1
1—.
1
l.E-07
J
*0.00
TO
45 00
10
10
ID
ID
10
2.0
6.5
9.5
6.5
28
29.7
30.2
190.1
348
204 e
o
T
JC
i>
2
1
4
15
20
20
' 2.E-O6
45.00
to
50.00
10
10
10
10
10
2.0
7.0
10.0
7.0
2.8
49 3
140.8
383.3
226 1
844
c
to
5
j
4
0
6
6
4
4.E-O7
• (Water InjeltedWro
) ((Depth_io| - [Depth Jrom])/[time] ' 10(bars)/[Gaugo Pressure [(bars
m fhe,/l?in ' 10<barsKac,ua' pressure(bars]
i^!? *‘
n
fDr values 1S-50 and neareTst in i
1lu<’i$_' a—' re'e«wwrtnedeqtoiqnerarest 1 forvalues 1-5; 2 for values 5-10: 5 for values 1O-15; edres    jo !qf values >50
19:33 amAppendix 4.a:
Laboratory Test Results - Soil,j> introduction
1*           P«-« Summe-y of Moratory teat
Project ^e lest «* .„ Gram Ana w Anefb^
,
Coofonf. Unit W„M. Direct SMar. cw Swel
,W>   are   carried   out   foiiow.ng   th.   appropriate   santpfe   „,M,XlQri t-<^> Md the standard procedure foiioreed to cany M ,he
herein.
f.1S»
----- ___
SNo
Type of Test
Standard
Grain Size Analysis - Hydrometer
BS Test 7(B)
H
----------- •
2.
Atterberg Limit
BS Test 2 (A)42(B)
Natural Moisture Content
BS Test 1(A)
4
Unit Weight
V“
Direct Shear
•
Free Swell
Gibb' &Holtz (1956)s
I'
6
Swelling Pressure
BS 1377:1975.Nile Irrigation and Drainage Project
Summary of Test Results
Date: 23/11/2010
Parameters
UBD-2
(0.50-0 60m)
UBD-2
(2.50-2.80m)
UBD-2                         UBD-6 (4 00-4.45m)            (1.70-2.00m)
UBD-6                1 UBD-6               1JBD-7
(4.50-5.00m) i           (8.0-
9.00m)
t2.80-3.45rh) '
i
Grain Size Analy sis
Clay %
Sih %
Sand %
Gravel %
1
•
•
3.00
11.76
25.54
59.70
-
8.00                     0.00
15.93                    2.42          1             - 76.07                     3.27
Atterberg Limit
Liquid limit %
Plastic Limit %
Plasticity Index % Dispersion by Double
Hydrometer
94.31           k  *  J
--
57.84
36.84
21.00
54.78
35.47
19.31
•
•
59.52
36.11
23.41
-
-
-
•
94.14
44.32
49 82
ND
ND
-
ND
-
ND
Linear Shrinkage (%)
•
-
15.61
-
1764
Natural Moisture Content (%)
-
:
-
•
■1
•/
Checked By 
Approved ByNile Irrigation and Drainage Project
Summary of Test Results
Date: 23/1172010
Parameters
Grain Size Analysis
Clay %
Silt %
Sand %
Gravel %
UBD-7
(4.60-4.80m)
UBD-2-US/1                 UBD-6-US/1
UBD-6-US/2                    UBD-7-US/1
(1.0-1 2m)
(1.0-1.2m)                     (3.40-3.85m)
(1.2-1.45m)
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
Atterberg Limit
Liquid limit %
Plastic Limit •/•
Plastic it> Index %
83.30
30.41
52.89
58.30
37 27
21.03
34.38
27.84
6.54
107.95
44.12
63.83
Dispersion by Double
Hydrometer
ND
ND
56.05
36.44
19.61
ND
-ND
ND
Unit Weight (gm/cc)
14.29
•
-
-
-
Natural Moisture Content (*/o)
-
23.38
25.43
37 12
35.70
_______________________Nile Irrigation and Drainage Project
Summary of Test Results
I)ate: 23/11/2010
I Parameters
[ UBD-2
(0.50-0.60m)
UBD-2
(2.50-2.80m)
| UBD-2
(4.00-4.45m)
UBD-6
(1.70-2.00m)
UBD-6
(4.50-5.00m)
UBD-6
(8.0-
9.00m)
T UBD-7
1 (2.80-3.45m)
1
Grain Size Analysis
Clay %
Silt %
Sand %
Gravel %
-
•
3 00
11.76
25.54
59.70
-
•
-
8.00
15.93
76.07
-
0.00
2.42
3.27
94.31
1
|
•
After berg Limit
Liquid limit %
Plastic Limit %
Plasticity Index %
57.84
36.84
21.00
54.78
35.47
19.31
•
-
59.52
36.11
23.41
-
-
-
-
94.14
44.32
49.82
Dispersion by Double
| Hydrometer
ND ND
1
ND         1    -
-
■J1
ND      1
Linear Shrinkage (%)
------- :------- 1
i
-
-
Natural Moisture Content (%)
1__
I
-
15.61             —4                                        —J 17.64
■ / L
-/
JNile Irrigation and Drainage Project
Summary of Test Results
Date: 23/11/2010
1 Parameters
HjBD-7
(4.60-4.80m)
UBD-2-US/1 (1.0-1.2m)
.
UBD-6-US/1
(1.0-1.2m) 1
-------- 1
UBD-6-US/2          1
(3 40-3.8 5m)
UBD-7-US/1
(1.2-1,45m)
Grain Size Analysis
Clay %
Silt %
Sand %
Gravel %
-
-
-
_______
1
1
-
-
-
*
*
•
-
-
♦
•
-------------------------- 1
•
•
•
Atterbcrg Limit
Liquid limit %
Plastic Limit %
Plasticity Index %
83.30
30.41
52.89
58.30
37.27
21.03
56.05
36.44
19.61
ND
34.38
27.84
6.54
107.95
44.12
63.83
Dispersion by Double
Hydrometer
ND
-ND
ND
Unit Weight (gm/cc)
ND
14.29
-
•
•
•
Natural Moisture Content (%)
-
23.38
25.43
37.12
35.70
Checked By
Approved By»
*
I 1
1
^7
i7*' Project: Client.
m rtPT ww uttc JTC£+ MPtfd IW7IH
euc-rw^ :
Nile Irrigation 8nd Drainage Project Addis Geo Systems CO. LTD
I♦
I
I
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i
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Loabon Upper Belles Storage I BHNc.         UBD-2
Depth(m) *. 0.50-0 60
Water Works Deal Supervision Enterprise
Service
[. -Soil 4 Material Tesfin Sun Type Disturbed 
Test Type Hydromcter^ith Dste '02/11/W
Total mass of sample.
60
SlM
No (
)p*y(*”e)
Mass   of   t Sitt*(&)
tantfsn* • R/Z j*l@
Mass rf
[<//. soil
Perantape
Rj fated
Cjemuhtitt "j
% Retained
No 10
2.00
551.10
551.10
0.00
0.00
0.00 ~
taen/qr
Passt*; lOOnn
No 16
1.18
558.90
539.48
0.58
1.09
1.09 *
Nt 50
0.60
516.70
518.90
2.20
4.12
5.2? “
No 50
0.3<J
488.20
491.83
3.63
6.80
12.00 ”
■9479 ~~8$00
No 100
0.15
481.90
485.05
3.15
5.90
17.90
82 10
No 200
0.08
459.20
461.80
2.60
4.87
22.77
.
77 23
pm
0.00
000
0.00
0.00
.
0.00
Specific Grurtty of soil
2.65
Test Temp erjtare, deg.c 2t
2
Eloped
Actlfa
Tenpralare
Corrected
Effective
Coefficient
Grom
^treenta/e
Turn
!«»)
Hydmmltr
Riadut^
Hydrometer
^jjdini
Depth
(cm)
K
Si^e
(mm) C  .
Finer
ombened
2
41.0001
22.0
35.0000
10.60
0.01332
0.0307
58.33
5
38.5001
) 22.0
32.5000
11.00
0.01332
0.0198
54.17
15
35.5001
) 22.0
29.5000
11.40
0.01332
0.0116
49.17
W
32.50*
9        22.0
26.5000
1190
0.01332
0.0084
44.17
60
30.000
0 22.0
24.0000
12.40
0.01332
0.0061
40.00
250
26.000
0 22.0
20.0000
13.00
0.01332
O.OO3O
33.33
1440
22.000
0 22.0
16.0000
13.70
0.01332
0.0013
26.67
Ort in Six
a Distribution Curve^BS
?
10000 nr woo - • an m -. -
Kt; - l
Tested by: Checked by
Approved :
-A* TTC
Water Works Design and
Supervision Enterprise
Laboratory Service
i'
I f^ ^^
: l
|
<1 ^a9ep(0iec'
Jpper Belles Storage'
Sam Type Disturbed
Test Type : I Iydrometcr(with out sofa) Dace: 12/11/10
<° UBl>2
^0 50° 60
Penmiaft
|  Cmfatnr
RtLunrJ
% Rftawd
Pfrirnlagf Pojfin
551.10.
538.90
55130
539.63
516.70
488.20
481.90,
459.20
519.00
492.02
484,99
461.66
0.00
1.22
3.83
0.00
1.22
5.05
100.00
98.78
94.95
6.37
515
11.42
16.57
88.58
8545
4,70
0.00
20.67
___  0.00
7933
0.00
H7
]
Its! Terffaru,
ittn,
22
Tfftpra/urt
corrected
Ejjtctivt
Coeficirrt
Gnu
Perrratage
ilytn^rirr
HyJrv^ffrr
Rtadiitg
Depth
(cm)
K
Sift
(mm)
Fmer
Gmhntd
Hr
-  155000
22.0
15.5000
13.70
0.01332
0.0349
25.83
j
11.0000
22.0
110000
1450
0.01332
0.0227
18.33
I
7.0000
22.0
7.0000
15.20
0.01332
0.0134
11.67
4.0000
22.0
40000
15.60
0.01332
0.0096
6.67
I 19
Si
3.0000
22.0
3.0000
15.80
0.01332
0.0068
5.00
I 19)            2.0000
22.0
2.0000
16.00
0.01332
0.0034
3.33
L             [       0.0000
22.0
OOOOO
16.30
0.01332
0.0014
0.00nun w* W* *T'rc
MX/7                ZrM
Project: Nile irrigator and Drainage Project
. Addis Geo Systems CO LTD Loainon: Upper Beles Storage I
BH-No. UBD-2
Depth(m): 0 50-0 60
Water Work
Supervwon
Labor.
tory Sei
’So# 4 Malarial Tastln
S*m Type : Disturbed Test   Type;   Double
Date: 12/11/m
^ydrotnet,
Grain Size Distribution Curve.BS
Grein Size
mm)
Gravel
Sand
Silt
ClayoMe^ *TTC
’ “*'"X“k»»™c0LT0
Water Works Design and Supervision Enterprise Laboratory
Service
Sam. Type : Disturbed
Test Type; Hydrometerfwith sot'n) Date 02/11/10
iX‘ dpperB*
ueo-i
Total mass
~ SU'irf
S*t*& _
~ Mtusofnm •
Krt ,SOll(g)
Mass of
Fit. jm7 (g)
Ptnrntagt
Rtiatnta
% Rs fat nt a
Ptrvrntage
Passing
i~             551.10
00C
o.oc
0.00
100.00
775
Ti8M
539.98
1.08
2.00
2.00
98.00
519.22
2J2
4.67
6.67
93.33
■'------- 060 f) IO
516.70
48820
494.15
5.95
11.02
17.69
82.31
^^055
008
481.90
487.40
5.50
10.19
27.87
72.13
--------
~ 459.20
462.82
3.62
6.70
34.57
65.43
0.00
0.00
0.00
0.00
0.00
i
i Sj
ja if soil              26J--------
1 irt 1 tnrpen                          22
itnrt, dtg.c
rr... f 4/£mXi
Tf^aiart
Cornett a
rj/ecftve
(.Atjjlatnt
Ptrtmfagr
7w
’ «r'
FyJrw*/tr
Piydnsmtttr R/adtng
Depth
(^f)
K
J7^r
(wurj
Ftntr
CambintJ
J 7.0000
22.0
31.0000
11.20
0.01343
0.0318
51.91
r>
35.0000
22.0
29.0000
11.50
0.01343
0.0204
48.56
0
30.5000
22.0
24.5000
12.30
0.01343
00122
41.02
—r:—
285000
220
22.5000
12.60
0.01343
0.0087
37.67
0
26 5000
22.0
20.5000
12.90
0.01343
0.0062
34.32
:«
22.0000
22.0
16.0000
13.70
0.01343
0.0031
26.79
w
18.0000
22.0
12.0000
14.30
0.01343
00013
20.09
Goin Size Distribution Curro.BS
.‘iff'-rvtxJ bynub'l Wf xm *TTC
Wild A7U7i>+            /
Project. Nile imgatxxi and Drainage Protect
Qrat Addis Geo Systems CO.LTD Loaooc Upper Belles Storage I BHNo. UBD-2
p;
Water Works Design an(1 Supervision Enterprise labors
Service
Soils Material Testing s „
Stun. t ype •• D^mrbed
Kw
Test Type Hydrometo(with out soln, Dutc: 02/11/W
■a
Dtpth'm):250-2 80
Tola/ mass o* sample.
60
Sit*
Masi of
Majs if /irar *
Mass of
Ptrrrntaff
Cnmn/atJut
Perantag
Kl
C ?«*£**’'
Sievefc)
Rr/.wr/ft/
Rzt sot/
Retamed
% Retasned
Ki 10
2.00
551.10
55t./0
0.00
0.00
OM
N» 16
lit
538.90
559.84
0.94
1.57
100 00
1.57
.
9843
No 30
0.60
516.70
519.46
2.76
4.60
6.17
9383
Nt 50
030
488.20
494.51
6.51
10.52
16.68
Nt 100
0.15
481.90
487.63
5.75
9.55
26.25
~7377]
Ko 200
0.08
459.20
463.20
4.00
6.67
32.90
67.10
pan
0.00
0.00
0.00
0.00
...t
iz:
~o.do
Esatud
AtSH&
Tfnpratnrr
Comae d
Effective
Coefficient
Grain
Prrrnla^t
Tom
(mj
Hjdrumfr?
Ra4>^
4tg.c
Hydrvfnt/rr
Readtr.t
Depth
(cm)
K
Si^e
(mm)
Finer
Combined
2
14.0000
22.0
14.0000
14.00
0.01343
0.0355
23.44
5
10.0000
22.0
10.0000
14.70
0.01343
0.0230
16.74
15
6.0000
22.0
6.0000
15.30
0.01343
0.0136
10.05
30
3.5000
22.0
3.5000
15.70
0.01343
0.0097
5.86
60
3.0000
22.0
30000
15.80
0.01343
0.0069
5.02
250
1.5000
225
1.5000
16.00
0.01343
0.0034
251
1440
0.5000
22.0
0.5000
16.20
0.01343
0.0014
0.84
Grain Size Divtribubon Curve,BS
Approved b)*
TT C
1
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^MfUTtsting^tctlon
Sim. Type; Disturbed
1 est Type : Double } lydromrter Date: 02/11/10
L-s"«sS"”9'1 !■< U^2
*>«*
Grain Srz» Dtotribution Corva.BS1
nin-f jP'tFf
«TTC
Water Works Design.
I
ni
jtcjh p«ind.
+ii
Mm+
Supervision Enterprise La
Service
So.U<& Material testing St
Project  Nile  Irrigation
and
Drainage
Project
Sun Type ■ Disturbed
t           Client:      Adds Geo Systems CO LTD Loauon upper Belles Storage I
BHNo. UBD-2 Dqithfm): 4 00-4 45
Vest Type • Wet Sieve * 1 lydrometei Date-.03/11/10
of sample hefc
oj sample aft
vr nwh, g
?r wash, g
236.50
201.70
i
JifW
Opmmgfm*)
Mail ct
Stevtfo
lass c pen ‘
Mast oj Ret. tfiil (g)
Pmtnfage
Retained
Cumniatm % Retained
~Pcvrentagc Passing
75.00
1800.00
1800.00
0.00
000
0.00
100.00
50.00
1205.50
1203.50
0.00
0.00
0.00
10000
57 50
1087.80
1087.80
0.00
0.00
0.00
100.00
25.00
1191.20
1191.20
0.00
0.00
0.00
100 00
19.00
718.50
748.40
29.90
12.64
1264
87.36
* i
i
12.50
586.10
625.30
39.20
16.58
29.22
70.78
9.50
598.40
613.30
14.90
6.30
35.52
64.48
4.75
578.10
605.90
27.80
11.75
47.27
52.73
2.56
533.00
556.60
23.60
9.98
57.25
42.75
2.00
551.10
556 90
5.80
2.45
59.70
40.30
1.18
538.90
554.00
1510
6 38
66.09
33.91
0.60
516.70
533 60
16.90
i
7.15
7323
26.77
0.30
488.20
502.00
13.80
5 84
79.07
20.93
0.15
481.90
492.00
1010
4.27
83.34
16.66
0.08
459.20
463.70
4.50
1.90
85.24
14.76
i
■»
PAN
425.50
460.40
34.90
14.76
100.00
0.00
Spea/ic Grant} oj soil
2.66
Test Temperature, depc              22
Efapstd
Actual
TtKpratxrv
Corrected
Effective
Coefficient
Grain
Percentage
j
Tint
(nio)
Hydrometer
Reading
<**<
Hydivmfter Reading
Depth
(cm)
K
5i^e
/mm)
Finer
Combined
i
2
20.0000
22.0
14.0000
14.00
0.01331
0.0352
8.43
5
18.0000
22.0
12.0000
14.30
0.01331
0.0225
722
15
165000
22.0
10.5000
14.60
0.01331
0.0131
6.3L
30
15.0000
22.0
9.0000
14.80
0.01331
0.0093_
60
14.0000
22.0
8.0000
15.00
0.01331
0.0067
5.42_
4.82
250
12.0000
22.0
6.0000
15.30
0.01331
0.0033
3.61
:!
U
1
1440
10.0000
22.0
4 5000
15.50
0.01331
0.0014
2Jj\
i
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Water  Works  Design  and Supervision Enterprise
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.. ^bff ^Material Taiting Saction Sam. Type : Disturbed
Test Type Combine Graph Date: 03/11/10
I»«’’
Grain Stte D^tnbuOon Curvw,BS
kIiro-H FVFt
*TTC
JTCJH MUA-td MCHfrf
V
Project Nile Irrigation and Drainage Project Cbcnt Addts Geo Systems CO LTD Locibon; Upper Belles Storage I
BH-No. UBD-6
Depth(ra): 1.70-2.00
Total ntarr -jf
Water Works Desigr Supervision Enterp
Laboratory Servv Soil A Material
Sam. Type • DhtuAcd Type: Hydrometer (with k>
Dsie.OVU/10
60
Sim
Na
Srm
Mojj    of   V Sievtfe)
'osj of am -
K/r joi/(g)
Marr of 'Iff rati fa)
Pm**!#?
R/latned
No10
2.00
551.10
551.10
0.00
0.00
Cumulate
% WttiUned
0.00
JPajfiny 100C
N* 16
1.18
538 90
538.94
0.04
0.07
0.07
Na 30
0.60
516.70
516.81
011
0.21
0.28
99l
^995
No 50
0 30
488.20
488.81
0.61
1.14
1.42
98*
No 100
0.15
481.90
483.90
200
3.75
5.17
94 1
No 200
O.tt
45920
461.91
2.71
5.07
10.24
.
8SC
P*'
___________
2.58
0.00
0.00
0.00
0.00
O.(
Specific Grant} of jail
Tert Tf^pfrulifn,
22
EM'ci
Aetna*          | Tenpratun
Corrected         Effective
Coefficient
C >rain
-Prrrnitop
Towe
ima)
Hydrnnit"
R/adty
Hyden*"ter
Reading
Depth
(cm)
K
Siqa
(mmj
Viner Cofnbtnta
2
49.0000
22.0
43.0000
9.20
0.01364
0.0293
72.*
5
44.0000
22.0
38.0000
1010
0.01364
0.0194
64.
15
38 5000
22 0
32.5000
11.00
0.01364
0.0117
55.\
so
355000
22.0
29.5000
11.40
0.01364
0 0084
49.
60
325000
22.0
26.5000
11.90
0.01364
0.0061
44.
250
28.000C
1 22.0
22.0000
12.70
0.01364
0.0031              37..
1440
23.500C
) 22.0
17.5000
13.40
0.01364
0.001 J 1          29.Belles Storage I
Water Work* Design and Supervision Enterprise Laboratory Service
<  SbffjA  llaterfa/TeiWng  Sectfon Sim. Type : Disturbed
TcjC Type : Hydrometer (with out sol’n) Date 01/11/10
mail oj famptt,
60
5**
9
(\pe* g(*P*3-
-^loo —‘ T7k
Mats of
5ievtfg)
Wats if tine ♦ R/r
Mass <f R//. soil (g)
Pemnlagt
Relatfted
Cim/atim % Retained
Percentage
Passing
351.10
551.10
0.00
0.00
0.00
10000
■^to”
538.90
541.21
2.31
4.33
4.53
95.67
’~"~(k60_
516.70
~030 ------ 0.15
008
4lfo.eu
481.90
459.20
51925
489 79
2.55
1.59
4.78
2.98
9.10 12.08
90.90
87 92
482.89
0.99
1.85
15.93
.
86.07
460.05
0.85
1.59
15.52
84.48
0.00
0.00
0.00
0.00
0.00
wJ
of soil
2.58
lest Itmpen    itxrr, deg.c        22
lenpruture
Correct'd
effective
Coefficient
Gnat
Percentage
H0WW**7
rvxJjflj
dfgc
Hydrometer
Reading
Depth
K
Siqt
(mm)
Finer
Combined
5i
283000
22.0
28.5000
11.60
0.01364
0.0328
47.50
5
23.0000
22.0
23.0000
12.50
0.01564
0.0216
58.35
If
17.0000
22.0
17.0000
13.50
0.01364
0.0129
28.33
11.5000
22.0
11.5000
14.40
0.01364
0.0095
19.17
Hi
10.5000
22.0
10.5000
14.60
0.01564
0.0067
1750
&              6.0000
22.0
6.0000
15.30
0.01364
0.0034
10.00
tw             2.0000
22.0
2.0000
16.00
0.01364
0.0014
3.331
i
I
na>4     rtPT     w>     *ttc JtCJH- P^nt-FA il?07frf
:•.•
Project
Water Works De»lgn Supervision Enterpr
Laboratory Servic Soil 4 Material Testing s
Nle Irrigation and Drainage Project
__ __ _ Add® Geo Systems CO. LTD Chart:
lotion Upper Belles Storage I BHNo         UBD-6
Deplh(m):1 70-2.00
S*m Type Disturbed
Test    Type    Double Date: Ol/ll/io
Hydrometer
J
Grain Size Distribution Curvo.BS
1000
1.00
0 10
0 01
000
i
1. 1
I
Grain Siz4 |mm)
u
I
[
Gravel
Sand
Clay
i
>
•I J
1 j
I
I
I
I
IHurt fir?* Wit *TTC
PML+A a 7070-1
and Drainage Project
n ., Nile Irrigation l J
fl Adda Geo Systems
,BX Upper Belles Storage UBB-t
COLTD I
Water Works Design and Supervision Enterprise Laboratory Service
Sam. Type : Disturbed
Test Type : Hydrometer(with soTn) Dice: 02/11/10
Total mtusof f^P^&
60
\lanof™* ‘
Mass of
PflVMlag
Retained
Catanlafi*
Ret. sot!
% Retained
Penrntage
Paerin
551.10
551.10
543.11
0.00
4.21
1226
20*4
6.30
0.00
7.02
516.70
528.96
509.14
488.20
20.43
34.90
10.50
0.00
7.02
27.45
62.35
72.85
100.00
92.98
72.55
37.65
27.15 \
461.13
1.93
3.22
76.07
23.93\
(A VC
y _
0.00
0.00
f *7 uf iod
262
0.00 Test Tempm
0.00 itKH, df&C
0.00
22
r
TenpniUfre
( oerected
EffiOnft
Coefficient
Groin
Perventag
7m
Iff I
f'-h+wnetcr
dtAr
Hydrometer
Reading
Depth
(cm)
K
Si^e
(mm)
Finer
Combined
165000
22.0
10.5000
14.60
0.01347
0.0364
17.62
i
150000
22.0
9.0000
14.80
0.01347
00232
15~10
If
13.5000
22.0
7.5000
15.10
0.01347
0.0135
12.59
JO
13.0000
22.0
7.0000
1520
0.01347
0.0096
11.75
1
50
12.5000
22.0
6.5000
15.20
0.01347
0.0068
10.91
JO
11.0000
22.0
5.0000
15.50
0.01347
0.0034
8.39
(440
10.5000
22.0
4.5000
15 50
0.01347
0.0014
7.55nm-i
n<jj
Project: Client
W? *'rTi:                                      z MOttt WNH
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Nte irrigation and Drainage Project Adds Geo Systems CO LTD
JTj
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Upper Belles Storage I
■w.wJSEL,
Sam. Type Disturbed ' T«t Type :WctSleve + Date: 02/11/10 
’ ttei
BHNo. UBD-6 Depth(m) 8 00-900
Totai mart of sample before aurA, /OfcfO
Total mass pf sample gjsrr wash. 1056.40
T«w Qwrfnn)
Mass of
SitrefgJ
last of MH R/f
Mass of Rz/. jw/ {X)
Perrtn/atf
Retained
('.umutaiin
% Retained
Percentage Passing
75.00
180000
1800.00
0.00
000
0.00
100.00
50.00
120150
120350
0.00
0.00
0.00
100.00
37.50
1087.80
1087.80
0.00
000
0.00
100.00
25.00
1191.20
1576.20
185.00
17.09
17,09
82.91
19.00
718.50
905.80
187.50
17 30
34.39
65.61
1250
586.10
802.10
216.00
19.95
54.34
45.66
950
59840
695.70
95.30
~ MOl
65.14
36.86
4.75
578.10
751.40
175.50
16.01
79.15
20.85
2.36
533.00
663.60
150.60
12.06
91.22
8.78
2.00
55110
584.60
3350
5.09
94 51
5.69
1.18
558.90
558.50
19.40
1.79
96.10
3.90
0.60
516.70
525.20
6.50
060
96.70
3.30
0.30
488.20
492.90
4.70
0.43
97.14
2.86
0.15
481.90
484.90
5.00
0.28
97.41
2.59
0.08
459.20
461.00
1.80
0.17
97.58
2.42
R4X
42550
451.70
2620
2.42
100.00
0.00
1082.60
Elapsed
•J Uf Ml
.Actual
Tenpralurt
CoTTUtcd
Effective
l eji I emperu Coefficient
acre, ttcg.t Grain
Pmenrag
Hjdmmeter
R/odt^
J%c
Hydrometer
Readme
Depth
(cm)
K
Si%e
(mm)
Finer
Combined
2
11.5000
22.0
5.5000
15.40
0.01292
0.0559
1.25
5
10.5000
22.0
4.5000
15.50
0.01292
0.0227
1.03
15
100000
22.0
4 0000
15.60
0.01292
0.0152
0.91_
30
8.5000
22.0
2.5000
15.90
0.01292
0.0004
J)5ff
60
7.5000
22.0
1.5000
16.00
0.01292
0.0067
05ff
250
6.0000
22.0
0.0000
16.50
0.01292
0.0055
o.oo
1440
55000
22.0
0.0000
16.30
0.01275
0.0014
I ?t UH** *TI': £'£SX*-,Tro
£ £."•«s,0,B9e
1^ o0[>6 C' 90°-9 00
Water Works Design and Supervision Enterprise Laboratory
Service
Soil A Material Testing Section Sam. Type: Disturbed
T   D e  ir st e T: 02/   ype11/   We10t Sieve + f iydrometrr
Grain Size Distribution Curve,69
A.|grt
w* *TTC w* , thiuh wr**
Water Works 0^
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Servin
So// & Mater/a/ TesjM »
P^.? N.telmgatK.nand Dra-nase Project (lent Addis Geo Systems CO. LTD Loctwn Upper Belles Storage I
BH-No U0O-7
Depthfm): 2.80-3.45
Sim Type : p„ lUf'
9 Secy,
Test Type: Hydros,«(with Date: 02/11/10 
n;
Total nasj of .'amf>u>£                60
SlfTf
M
StfVf
Mats of
SttOtfo
\
faJtofswe 4
Mass of
R//. sail (&
Perwttqgt
Rs tamed
Cm/ta/m % Retained
Percentage Passing
Ni/0
2.00
551.10
551.10
0.00
0.00
0.00
M 16
1.18
538.90
540.48
1.58
2.63
100.00
2.63
-            ~9757
M30
0.60
51620
519.58
2.88
4.80
7.43
92.57
M50
0.30
488.20
490.22
2.02
3.37
10.80
89.20
No 100
0.15
481.90
482.90
/.oo
1.67
12.47
~8755
No 200
008
459.20
459.99
0.79
1.32
13.78
o.oo\
8622
0.00
0.00
0.00
0.00'
Spufc Grant) of toil 2.67 
Tut Ttnepemtun,
22
fA4■
buspiea
Ami
Tenpratun
Comets d
F.tfatn*
Coefficient
Grain
Pernntag
Tint
("•)
liydrwmtrr
de^.c
JljdfMMtfT
RttldlH&
Depth
ft*)
K
Siy
tfnm)
Finer
Combined
2
55.0000
22.0
49.0000
8.30
0.01327
0,0270
81 30
5
54.0000
22.0
48.0000
840
0.01327
0.0172
79.64
15
52.0000
22.0
46.0000
8.80
0.01327
0.0102
76.32
30
50.5000
22.0
44.5000
9.00
0.01327
0.0073
73.81
60
49.0000
22.0
43.0000
920
0.01327
0.0052
71.34
250
46.0000
22.0
40.0000
9.70
0.01327
0.0026
66.37
1440
42.0000
22.0
36.0000
10.40
0.01327
0.0011
59.73
Grain Size DwVibutk>n Curvo.BS* rI”rn
.1 hioifr*
and Drainage Project
Water Works Design and Supervision Enterprise Laboratory
Service
So# A Maferfa/ Testing Section
Sam. Type: Disturbed
T D a a t teT :ype10/11/ Hydr10ometer^uith out soro)
60
rS.
iX
^-xc°LTD
, JPP«0«"e5SM^
ubd-
7
‘^250-345
ToUilmasiof
Rr/
Perrrnfage
Retained
CjVHUilfa*
% Retained
PtrvnUgt
Pairing
551.10
551.10
0.00
538.98
516.93
489.04
483.75
0.08
0.23
0.84
1.85
013
0.38
1.40
3.08
0.00
0.13
0.52
1.92
5.00
100.00 99.87 9948
459.20
461 30
0.00
2.10
0.00
3.50
0.00
8.50_____
goo]
98.08 95.00 91.50
0.00
y u:
 JW
2.67
Ttft Tfmpfratun, de^.c 22
T
Corrected
Effective
Coefficient
Cna'n
Ptrctutage
j*
i <’M_l».
^anwler
Hydrometer
Reading
Depth
(eny
K
Si^v
(mmj
Finer
Combentd
1
24.0000
22.0
24.0000
12.4
0.01327
0.0330
39.82
1f
16M00
22.0
16.0000
13.7
0.01327
0.0220
26J5
hr-
9.5000
22.0
9.5000
14.7
0.01327
0.0131
15.76
1X
5.5000
22.0
5.5000
15.4
0.01327
0.0095
9.13
5.0000
22.0
5.0000
15.5
0.01327
0.0067
8.30
2.5000
22.0
2.5000
15.9
0.01327
0.0033
4.15
[ Tao     1.0000
22.0
1.0000
16.1
0.01327
0.0014
1.66
Grain Size Distribution Curve,BS
rnrn-H /“tPl UTTC JTCJ?
pontfd inmi
Water Works Desian
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4
Service
_ ____ ,*» • .iSl i
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Soli
& Material Testing s
S»m. Type D
isturbed
Addis Geo Systems CO LTD
Upper Belles Storage I
Test    Type
D»tc 02/H/10
HydrometctCwiih    out    v
UBD-7
Grain Size Distribution Curvo.BS
100.00
90  00
5*        8000
- 7000
• 6000
T         5000
♦*      4000
• 3000
g **
a. woo
000
001
0 001
1 4I
!
i
Gravel
01
I
Grain SLzalrpm) , Sand
I
J
/Water Works Design and Supervision Enterprise
Laboratory Service Soff 4 M^Sria/Testf^ Mectfon
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Li Ni""S,^COLTD
S*m. Type Disturbed Test lypc : Hydrometer Dire: 10/11/10
j6D-7
4 60-* 00
m&r of lamp k, f
60
3
Mau of
551.10 558.90 516.70 488.20 481.90 4 $9.20
’uav G^
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d*i
7 */r/>rjX*rr
Corrected
Effective
Coefficient
Grau
Prmntdgt
I
r*
.wrl
^melrr
Hydrometer
Reading
Dtpth
™
K
Sqr
'aiij
Finer Combined
i
50.5000
22.0
445000
9 00
0.01414
0.0300
81.28
If
49.0000
22.0
43.0000
9.20
0.01414
0.0192
7854
r;
47,0000
22.0
41.0000
9.60
0.01414
00113
74.89
I»
45.0000
22.0
39.0000
9.90
0.01414
0.0081
71.23
*
44.5000
22.0
38 5000
10.00
0.01414
0.0058
70.32
I :«         41.0000
22.0
35.0000
10.60
0.01414
0.0029
63.93
Wl      [ 38.0000
22.0
32.0000
11.10
0.01414
0.0012
58.45Water Works Desir,
S ^on
Laboratory Servjc *
p,
and Drainage Project Addis Geo Systems CO.LTD
s
S °"4 Maftial Tt^ng  -
s
Loauon Upper Bedes Stooge I
BH-No. UBD-7
Depdi(m) .46
Stm. 1 ypc : Disturbed T«r Type: BydrOmctcr(wit. Date: 10/11/10 
*^0
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loloi rums of simph.l
60
Grain Sirs Distribution Curve,BS
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1 ^-hdb).
styprvfvd h:»»**
Water Works Design and Supervision Enterprise
Laboratory Service
-n and Drainage Project Systems CO LTD
Sim Type Disturbed
Test type : Double Hydrometer Date: 10/11/10
J
USD-? ^4.604M
w°(*'
Grain Size Distribution Curve,BS* TTC
•> i
I
t, 7.'
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Negation and Drainage Project Adds Geo Systems CO LTD
Cbent:
LoaDor. Upper Belles Storage I BHNo. UBD-2-US/1
Dcp<h(m) ‘ IO®*1 20
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W’terWort.,^ Superv|,i0ll E »" »n<i
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: Soil 4 Material t&ffa, Sam.Type: Undisturbed 9 S^n Test Type Hydrometer
Date: 11/11/10
GO
Sitvt
MiuscJ
liuiofiint
Matt of
Perrenldtf
Gumdathi
No
Sitvffe)
Rtf.wi/(tf
R/A soil (g)
Retained
% Reta/ned
PtfTWag
P^lin;
1
I
N« 10
zoo
551.10
552.11
0.00
0.00
0.00
~ioooo
N’»M
1.18
558.90
542.10
1.01
1.76
1.76
~98J4
N*J0
0.60
516.70
520.42
3.20
5.59
7.35
92.65
No 59
0.30
488.20
491.16
3.72
6.50
13.85
^8615
Nt 100
0.15
481.90
484.12
2.96
5.17
19.03
80.9'
Nt 200
0.08
459.20
459.20
2.22
3.88
22.90
77J0
pan
0.00
0.00
0.00
0.001
0.00
Etyita
Aetna/
Tenpruiuvr
Carrtcltd
Effect™
Coefficient
Grain
Ptrmt/a^f
Tutt
(min)
F.ydrwntttr
faditl
Hjdwnffta Reading
Depth
(an)
K
Finer Combined
2
45.5000
22.0
39.5000
9.80
0.01343
0.0297
69.33
5
43.0000
22.0
37.0000
10.20
0.01343
0.0192
64.94
15
40.0000
22.0
34.0000
10.70
0.01343
0.0113
59.67
30
37.5000
22.0
31.5000
11.10
0.01343
0.0082
55.29
60
35.5000
22.0
29.5000
11.40
0.01343
0.0059
51.78
250
31.5000
22.0
25.5000
12.10
0.01343
O.OO3O
44.76
1440
25 5000
22.0
23.5000
12.40
0.01343
0.0012
4125
41
&i< M"W+
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^.e^COLTD
idtsC--e‘' . ubd-2-USM
Water Works Design and Supervision Enterprise
Laboratory Service
Sira Type: Lndwturixd
Test Type: Hydromcter(wiih out join)
Dite: 11/11/10
1
Total        of sample, &              60
loss of SltVt
M OSs of
I
1
*1 fa*
Moss  of SttH&
BjIjoi1(^    Ret. soil &
Pfrcftttagt Rt/aintd
Cu^tUtnt
*i K/Zwwd
Pmtntagi
Passing
-—
J7J
j 551.fi
552.06
0.0G
> 0.0(
0.00
100.00
j         538.9b
541 86
0.98
1.71
1.71
98.29
-------- MC
■""OX ' oTs
tz^
)        516.70
521.40
2.90
5.07
6.78
9322
'        488.20
491.28
4.70
8.21
14.99
85.01
481.90 " 459.20
484.64
308
5.38
20.37
79.63
459.20
0.00
2.74
4.79
25.16
74.84
0.00
0.00
0.00
0.00
Test Temperstart, de&.c 22
~Am>
T/npratart
CofTTiftd
Effecttoe
Coqfiatnt
Grain
Percentage
sn
•*' !
fa
Hydrometer
Dtpth
(«»/
K
Silt
(fa
Fnar Combined
1          17.5000
22.0
17.5000
13.40
0.01343
0.0348
30.71
f
12.5000
22.0
12.5000
14.20
0.01343
0.0226
2124
tj
1.5000
22.0
8.5000
14.90
0.01343
0.0134
1422
X
6.5000
22.0
6.5000
15.20
0.01343
0.0096
11.41
2»  2.0000
4.5000
22.0
4.5000
15.50
0.01343
0.0068
720
22.0
2.0000
16.00
0.01343
0.0034
3.51
1.5000
22.0
1.5000
16.00
0.01343
0.0014
2.63I®
Water Works De |
Supervision Ente ^
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Laboratory s  v? Soil & Material Tesfin
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„ Ni»>'im9a«“"'’
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Sim. Type: Undisturbed 9 S*Ctl°° Test Type: Double Hydromete- Due: 11/11/10
;
BH-No. UBD-2-US/1
Depth(m):100-1 20Water Works Design and
Supervision Enterprise
Laboratory Service
So 'l & Material Testing Section ;
and Drainage Project
Sim. Type : Undisturbed
1 est Type : Hydrometer
Date: 11/11/10
■j4?' U0£> '
6 US/1
<00-120
f sample, &
60
"'Sv*''
tert")-.
"'200
- tTs
Mart of
Sttvafg)
fan of Jim
Rr/ .joi/tfj
Majj of
R//. iaJ (g)
PfraMap
Retained
Cmntiatiee
% Rstaiiud
Pmotqgt
Pajiinj
Ji-*
" 551.10
5)8.90
551.34
0.00
0.00
0.00
room
539.84
0.24
0.42
0.42
9958
------- ~060
516.70
518.10
0.94
1.64
2.06
97,94
' 0JO
488.20
490.13
1.40
2.44
4.50
9550
~        0.15
481.90
484 14
1.93
3.36
7.86
92.14
*4 «W
459.20
45920
2.24
3.91
11.77
88.23
0.00
0.00
0.00
M
jjcfiCnP
0.00
0.00
,n ot tot/              2.66
TfJt TtmpfralMrt, deg.c 22
Aftwi
TflfpnjntrT
Corrrctfd
Effective
Coefficient
Grata
Percentage
Tm
•m
tydnatfltr
Ka>^
dt&C
Hydrometer Readme
Depth
(cmj
K
Si#
(m)
Finer
Csmbtntd
500000
22.0
44.0000
9.10
001331
0.0284
76J3
J
450000
22.0
39.0000
9.90
0.01331
0.0187
67.84
13
40.5000
22.0
34.5000
10.60
0.01331
0.0112
6001
W
38.0000
22.0
32.0000
11.10
0.01331
0.0081
5566
a
35.5000
22.0
29.5000
11.40
0.01331
0.0058
51.31
M)
31.0000
22.0
25.0000
12.20
0.01331
0.0029
43.49
•no
280000
22.0
22.0000
12.70
0.01331
0.0012
38.27Water Works De |
8 ari
FAPt-H W"fr
S-P-v-ton E
Laboratory Servi “
c
Prit
rr^«’n and Dramage Project
Add® Geo Systems CO LTD
Upper Belles Storage I
x So#t*»««<airMBll<,s
Sam. Type : Undisturbed ™ Test Type : Hydrometer^* 0U( Date: 11/11/10 
°ln>
BH-No. UBD-6-US/1
Depth(m): 1         20
maji oj sample. &60
Sieve
Nt
Mojj of
Sieved
iiJJ Of HM
R/r.jwV^
Maj j of R/7. soil (gj
Percentage
Retaited
Cnmnlattm
% Retained
" Nt M
2.00
551.10
551.22
0.00
0.00
0.00
PtrUHfagt Pasting
100.00
1.18
538 90
539.80
0.12
0.21
0.21
99.79
NH0
060
516.70
518.67
0.90
1.57
1.78
9822
030\
488.20
490.63\
1.97'
3.43
5.21
94.79
Nt 100
0.15
481.90
48433
2.43
4.24
9.45
90.55
Ne200
0.08
45920
459.20
2.43
4.24
13.69
86.31
pan
0.00
0.00
0.00
0.00
ooo
\ deg.c 22
Ehfued
Actual
Tenprutnrt
Cnrrrcted
Effective
Coefficient
Grain
Pervtnfagt
Tone
(mJ
R/Jity
Hydrometer
Redoing
Depth
M
K
(mm)
Piner Combined
2
18.5000
22.0
18.5000
13.20
0.01331
0.0342
32.18
5
12.5000
22.0
12.5000
14.20
0.01331
0.0224
21.74
15
8.0000
22.0
8.0000
15.00
0.01331
0.0133
13.92
30
6.0000
22.0
6.0000
15.30
0.01331
0.0095
10.44
60
4.0000
22.0
4.0000
15.60
0.01331
0.0068
6.96
250
1.5000
22.0
1.5000
16.00
0.01331
0.0034
2.61
1440
1.0000
22.0
1.0000
16.10
0.01331
0.0014
1.74-
■Ol'TC
Water Works Oealgn and
Supervision Enterprise
Laboratory Service
i-?.Spff 4 Mitefaffating section
■^nSt^1 and Draina9B PrOieCt
Sim. Type: Undisturbed
Test Type : Double Hvdrometer Date: 11/11/10
1 00-1 20
.Appmtd bfI
nan wf mv; *ttc j?c#
P-IHd-fd A701lbf i
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fu 
Water Works Design Supervision Enterprise Ubc™nR.
Service
7? Soil * Material Testing Section
Nrie Imgabon and Drainage Project
Sim     Type     Undisturbed
Profit:
Client: l.odDon
Addis Geo Systems CO LTD
Test      Type-.Hydrometer
Upper Belles Storage I
Date : 11/tt/tO
BH-No. UBO-6-US/2
Depth(m): 3 40-3 85
Total man o'.
60
Sieve
No
Sinn
Mau of
Sifted
Mass of
RrA sot! (&)
Percentage
Retained
Citrnnlattm % Retained
Percentage
Pasting
No 10
2.00
551.10
551.67
0.00
0.00
0.00
No 16
1.18
538.90
546.09
0.57
Moo
0.98
0.98
99.02
No 30
0.60
516.70
534.27
7.19
12.39
15.57
866)
No 50
030
488.20
494.93
17.57
50.27
43.64
56)6
No 100
0.15
48190
484.57
6.75\
11.60
55.24
44.76
No 200
0.08
459.20
459.20
2.67
4.60
59.84
40.16
pn
000
0.00
0.00
0.00
000
Etyrtd
Actual
Tenprufnrt
Corrected
Effective
Coefficient
Grain
Percentage
Ton
■mtn
Hydrtmder
R/iii/rn^
i lydrometer
Reading
Depth
(c»)
K
Si^f
frnm)
Finer
Combmed
2
20.5000
22.0
14.5000
15.90
0.01559
0.0353
25.04
5
18.5000
22.0
12.5000
14.20
0.01359
0.0226
21.59
15
16.5000
22.0
10.5000
14.60
0.01559
0.0132
18.13
JO
16.0000
22.0
10.0000
14.70
0.01519
0.0094
17.27
60
15.0000
22.0
9.0000
1480
0.01559
0.0067
15.54
250
15.5000
22.0
7.5000
15.10
0.01 J 39
0.0033
12.95
1440
12.0000
22.0
6.0000
15.50
0.01339
0.0014
1036
Grain Size Distribution Curve,BS
I
I
10
GfBV«l
1 0.1
Sand
Grain Sizej (mm)
0.01
SIH
0001
-J L-- X----- Z-----s--- js- l
tested by:
Checked by :
Approved by :
!
If
L s'
L, u81s *ttC
’“‘"^Xs.emsCOlTO
OBOES'?
340-3 85
Water Work, D«ian ,nd
i SuP«vialon Enterprise laboratory
Service
i ?i.Spn 4          Testing Section Sam Type: Undisturbed
Test Type Hydromcterfwith out sol'n) Date: 11/11/10
Kr/
Mass of R/f. soil &
Cjatniadvr % Ullawd
o&jffL ^200 - Hi
Mau of ’      551.io
Pmsas^p
Pawn
551.58
544.44
0.00
0.48
0.00
0.83
0.00
100.00
0.83
99.17
516.70
554.29
5.54
955
10.37
89.6)
—olo ------- 0T5
48820
497.49
17.59
50.51
40.68
59.32
48190
485.46
9.29
16.01
56.69
45.51
oox
459.20
459.20
3.56
6.13
62.82
37.18
0.00
000
0.00
0.00
0.00
Li——t
Actual
TfK^ a7urt
r
Corrected
Effective
Coefficient
Gnua
Pfrcrit!af<
*31,'
plydrorntter
RsadOft
Depth
(an/
K
Sl^t
imn;
Finer
Contbmtd
11.5000
22.0
11.5000
14.40
0.01339
0.0359
5
19.86
75000
22.0
7.5000
15.10
0.01339
0.0233
12.95
i 11
5.0000\
22.0
5.0000
15.50
0.01339
0.0136
863
0
JO
4.0000
22.0
4 0000
15.60
0.01339
0.0097
6 91
2»
2 5000
22.0
2.5000
15.90
0.01339
0.0069
4.32
10000
22.0
1.0000
16.10
0.01339
0.0034
1.73
l«o
0.5000
22.0
05000
16.20
0.01339
0.0014
0.86
Grain Size Distribution Curvs.BS
i'a
i1nabl /Ml AW? *TTC ACA
Wt-Fd A707rt-+
Sam. Type Undisturbed Test Type D°ub'c Hydrometer Ehte-.U/U/W
Water Work* De*|9n and Supervision Enterprise LabOrtv^
Service
Soil & Material Test,n  Secton
9
Pnixt
Nile  Irrigation  and  Drainage  Project
Chait:
Adds Geo Systems CO LTD
Ix»aoon: Upper Belles Storage I BHNo. UBD-6-US^
Dcpth'm): 3 40-3.85
Grain Size Distribution Curve,BS
100 00
90 00
80 00
70 00
60 00
5000
40 00
30 00
20 00
1000
000
10
1 0.1
0 01
0001                   ooo
Grain Sizetfnm)
Gravel
Sand
Silt
Clay
Tultd b) Checked by.FtrW WW IlTTE
## "Mi hltHfr+
Water Works Design and
Supervision Enterprise
Laboratory Service
' ■r
-
r
title irr-i^gtafon   tionanadndDrDarina;inage Project Adds Geo Systems CO LTD
Upper Belles Storage I U0D-7-US/1
120-145
Total mass ofwrplt, £
Sam. Type: L’nduturbed Test Type : Hydrometer Date: H/ll/W
60
Mast«/ Sievefa
551.10 558.90
~ 516.70 488.20
481.90 459.20
(Air of neve Ret
554.04 541.59
518.Q7 488.76 482.17 459.20
0.00
Marr of
R/r. soil
aoo
2.94 2.69
1.37 0.56 0.27 0.00
Ptntntye Retained
0.00
5.15
4.72
2.40 0.98 0.47 0.00
Cttwnirtnv
% Rftaincd
0.00
5.15
9.87
12.27 13.25 13.73
0.00
PrrvtHLig' Pii;::ng
100.00 94,85
90/3
87,73
86.75
86.27 0.00
7yJ zbiiu/
IjJtTmpfratMrr, Jtf.c
Tftp mt art
Corrtrttd
Ejfrrth*
CtcffiatHf
(rrm
Pmtnfag
—X—
1
an.
Hjdwwftr
R/a£tj
Hydrofifter
Depth
(an)
K
Inn)
Finr
Ctnbintd
t
535000
22.0
47.5000
8.50
0.01339
0.0276
83.47
5
525000
22.0
46.5000
8.70
0.01359
0.0177
81.71
515000
22.0
45.5000
8 80
0.01339
0.0103
79.95
f
505000
22.0
44.5000
9.00
0.01559
0.0073
78.19
0
50.0000
22.0
44.0000
9.10
0.01559
0.0052
77.32
?W
495000
22.0
43.5000
9.10
0.01339
0.0026
76.44
49.0000
22.0
43.0000
9.20
0.01339
0.0011
75.56
Grain Stea Distribiftton Curva.BS
nn
Approv'd by
-y0
rnubi wl W* *TTC
stjtt MUfrH MOTH-
ru e
■ * <
is/*.
Sofr.fc Mate^
L ‘^ x^
s
Project Nile Irrigation and Drainage Project (j^at. Addis Geo Systems CO.LTD
Loaaorr Upper Belles Storage I
BH No. UBD-7-USH
Depth(m): 1 20-1 45
Sam            ■*>        SZSd®®        S<*uon        •.
T«tType H
;   ydfon)e c
,
Dale; 11/11/10 WUlOu‘^n)
Total wi ojsamffo. jj               60
Sv*
No
Sint OfinatfMitji
2.00
1.18
Mojs of
'ajj of rieve
R// .joil(g)
554.09
542.15
Man of
Rrf. nil
Ptrrrntaff
Rrtatned
% Rrio/^ejl
Nt fO
551.10
538.90
0.00]
MM
OOO
2.99
0.00
524
Ni 50
0.60          51630          518.29               3.25               5.70            10.94             8906
Paijir.;
10()Cu\
94 76
No 50
0)0          48820          488.81               1.59               2.79              13.7V          86.27
N# 100
No 200
015
0.08
481.90
459.20
482.10
459.20
0.61
0.20
1.07
0.35
14.80
15.15
85.20
84.85
fan
0.00
000
0.00
0.00
0.00
Specific Gravity of loti         2.64
Tert Tempe ratnrt. i/rr r      22
Eiapted
Ttnpntfxn | Corrected
Effort:™
Time
(min)
Ptntnlag
Viner Combined
2
5
15
50
60
Actual
Hydrwter vaadtn^
23.5000
20.0000
15.0000
12.5000
10.0000
6.0000
22.0
22.0
22.0
22.0
22.0
22.0
Hydrometer
Reading
23.5000
20.0000
15.0000
12.5000
10.0000
250
6.0000
12.40
13.00
13.80
14.20
14.70
15.30
Coefficient
K
0.01339
0.01339
0.01339
0.01539
0.01339
0.01339
Grain
Si^t (mmj
0.0333
0.0216
0.0128
00092
00066
0.0033
41.29
35.14
26.36
21.96
17.57
10.54
1440
4.0000
1 ^0
4.0000
15.60
0.01339
0.0014
7.03
Grain Sire Distribution Curve,BS
*
c
10000
9000
BO 00
7000
iu
**
60 30
5000
c
£
4000
30 00
20 00
1000
ooo
T«rt^ by:______A*^__
1 - >■fmil *’
rT c
.
Water Works Design and
Supervision Enterprise
Laboratory Service
Soil & Material Testing Section
_ *' S>SV«»
n
m,COLT
Smti. Type : Undisturbed
D Te a s t t e: T11/ ype11/: D10ouble Hydrometer
'■>
H* j 20-1 45
Grain Sire Dtetri button Curve,BS
I
10
1 0.1 001
0001 000
Gravel
Sand
]
Silt
J I
slppwti by :______ •V’-
rat nft         ♦TTTE
e"
jrtJH
M1U+
T«s 251-116 18 55
Waterworks^ Supervision Enterprise Cem
Laboratory Service’^1
Soil&NlitwlUTittjnf. -
♦501
Se ^ion
F W 251 -116-61 53 71«1 08 98
«<n»l w.w d».«©«ttiionetet Project Nile irrigation and Drainage Project Client Adds Geo Systems CO LTD Location Upper Belles Storage I
BH No UBO 2
Depth (m) 0 50-0 60
liquid and plastic limit DETERMINATIONS
DATA AND COMPUTATION SHEET
PO.Box 256:
Addle Ababa
Ethiopia
Sample type tlndisturbed
Testtype.AttertiergUmft
Date 28/11/2010
T ype Crf IMI
LL
IL
LL
LL
Conteiner No
343
160
172
147
No oCBtowe
33
27
22
15
Mot sample* Tenwtt
33.266
34.500
35610
36 100
W of «nv* ♦ Tom dry
26.690
27.350
28 010
28 210
Mofwefr
6570
7 150
7 600
7.890
Ten
14960
14.930
15 200
15.010
wtofdry eon
11.730
12.420
12.810
13.200
Wteer content %
56.010
57.568
59.329
59 773
Type of toil
PL
PL
Container No
348
189
W.of temple Tare wet
32 760
32 750
VIA of sample Tan dry
2t980
27 760
M of wiler
4 780
4 990
Tin
15.030
14 190
wl of dry tod
12950
13.570
•Vater content %
36.911
36.772
36 842
Flow curve
61000
* 60 000
| 59000
| 56.000
£ 57 000
° 56000
55.000
Result
L L 57 84%
PL^
88 84
-*
10
25
Number tf Blowv
100
p.l 21.00%
Tested
CheckedWater Works Design and
Supervision Enterprise Central
•***
I
Laboratory Service
P.O Box 2561
Addta Ababa
5                                   Let
Fax ?     . , 4Mthlon’
-
Ethiopia
'<£tion    ‘and    Drainage    Project
Nie                 Systems CO. LTD
Sample type: Undisturbed
^^elles Storage I
Test type . Attertoerg Limit
m. upp*,
Date 28/11/2010
f u00'2 n
' v 2 50-2 SO
LL
2*——--------
LL
108
—■                                     28
—
------ --—
gy»H* - -
'31 59CL 25 750 ~5.840~ T4 7‘7(f
10  980
53 186
32.610
26 220
6 390
14.416
11.810
54.107
LL
110
22
33 540
26 840
6 706
14.840
12 000
551933
LL
122
15
34.910 27.670
7 240
15  630
12.640
57 278
cadet
PL
PL
ry*  No
4
177
127
Ifurrpa ♦ Tara **•<
34470
34 450
Harps* Tara dry
29 360
29 390
Ita
5 110
5 060
14 950
15 130
14410
14 260
35 461
35 484
35.47
Result LL 54.78% PL 35.47% P I 19.31%Wil r^PT WW ♦TTTC
jre>+ waMt HtH
1191*4
'
Water Works Design and Supervision Enterprise Central
Laboratory Service
MZ/7 
f^A .^.
Td   251   -   116-18   55   16«1   45   011
Fax 251 - 116 - 81 53 71*61 08 98
P.O Box 2561
Addis Ababa
Ethiopia
'on
e-mail w.w.d-t.eQethlonetet
Project
Nite  Irrigation  and  Drainage  Project
Client:
Addis Geo Systems CO LTD
Locabon Upper Belles Storage I BH No : UBD-7
Depth (m): 2.60-3.45
LIQUIO ANO PLASTIC LIMH DETERMINATIONS
DATA AND COMPUTATION SHEET
Sampte type Undisturbed Test   type   Atterberg   Limit Date 28/11/2010
I pc of test
LL
LL
LL
LL
ComeifwNo
156
350
386
24
No. ol Btowi
36
29
23
15
W.tf sample ♦ Tare war
34.400
35.580
36.720
“ 37 530
WLof sample ♦ Tare dry
24.760
25570
25.970
26 320
Wt Of water
9.640
10.010
10.750
11 210
Tara
14240
14 890
14 660
14 750
wtofdry sol
10.520
10.680
11.310
11 570
Water content %
91 635
93 727
95.049
96 889
Type of mt
PL
PL
Container No
98
148
W Of sampit ♦ Taro we*
29 660
29 800
VM of simple ♦ Tare dry
26280
24 890
VM of water
4.580
4.910
Tire
14.900
13.860
Of dry Mil
10.380
11.030
Water content %
44 123
44 515
44 319
Flow curve
Result
LL_ 94.14% p L 44.32%~ PI 49.82%
Tested By 
Checked ByjtfJW HTTTC
**»»”*
Water Works Design and Supervision Enterprise Central
Laboratory Service
fW"
rui/w
^
Tti 251-118- 1B5!
251-   110-1855   16/61   45    01
fFl>t, 225511-■111816-0. 1  53  71/61  08  98
, t--mmitHU ww..ww.dd..ft..ee@e Qetthhlloonneett..e,,t
NHe Irrig«aftlnion; and Dra-i-n--a-g--e Project ’^7 Adda Geo Systems CO LTD
'* upper Belles Storage I U8M
Addis Ababa
Ethiopia
Sample type Undisturbed Test type Atterberg Limit Date 28/11/2010
;r ^Mnos
^COMfVT^TfON SHEET
------ -r-
LL
341
Ctqw m?
34
IX
100
23
M^irc*•Tot wt
31 370
32 430
K/iry ♦ fom g-z
25 290
25.910
‘ 6.080
6 520
35.590
27.900
7690
15.110
ZEZ
16
36.570 28.360
8210
WfuMF _________
14.790" 10.500
37.905
14.880
14 980
lUfTUi
11 030
12 790
13.380
59.112
60.125
61 360
Pt
PL
CWfrNc
77
128
Mb ww ♦ T*n» w*t
31.^40
31.470
tiurpw* Tare (fry
27.180
27 040
wy«m
4.360
4.430
*n
15060
14 820
12 120
12 220
*» onrts
35 974
36 252
36 113
Fk>w curve
Result
L.L 59.52% PL        3611% P.l 2341%
fIW r*.PT AIM? ♦TTTC KJH mMt Hltd
irrnf v\y
rtUrrwXtfT itaA I 'M/2
Water Works Doalgn and s Supervision Enterprise Centri 4 Laboratory Sorvlce
T«* HI- 116-18 55 16351 4501
F«t Mt • 116-61 S3 71«t 08 98
w w dieftethlonet »t Prced Me iTuatKxi and Drainage Project On;: Addis Geo Systems CO LTD LocsXn Upper 6ete$ Storage I
BN No : UBO-7
DepCh(nt) 4 604.60 IIOUOANCRASTICIMT CETtRiaHKTlOKS
DM AND COMPUTATION SHEET
Soil AMeteriai Tutlhg Settlor,
P 0 Box 2661
Addis Ababa
Ethiopia
Sample type. Undisturbed Test type Atterberg limit Date 28/11/2010
Tywtf test
LL
LL
LL
LL
DonanerNo
74
114
131
178
No of Bfcer.
33
28
22
15
MtfttTpfe* T«tw*
28 350
29.620
30260
31.910
same* ♦ Tn 6.y
22 090
22 700
23150
23.990
Mdsiv
6 260
6 920
7.110
7.920
Tbv
14.370
14.390
14.740
14 750
dry d
7 720
8310
8410
9 240
81088
83.273
84 542
85.714
TjctdM
PL
PL
CarsBhet Na
385
131
Mcf samp* • Tan wet
26 650
26.510
Wd srrfc ♦ Toe dry
23 810
23 800
W.cfwttr
2 840
2.710
Tse
14 590
14.770
•rtf Gy si
9 220
9.030
Svrtrccrtwt*
30.803
30.011
30 407
Rew curve
X 88.000
5
c 
8
a?*
• 0
2
84 000
82000
80 000
Result
L L 83.30% p.L 30.41% PI 52 89%
Tested By Checked Approved ByiW vrrrg
Water Works Design and Supervision Enterprise Central
'trSF? Laboratory Service
* tun*                               1
aitTtl 251 ■ 116 • 18 55 IM1 45 01
fff 251 -116-0153 71381 00 gg
w.wd.9.9&*thlon*tot
t NM Imgabon and Drainage Project Addis Geo Sy sterna CO LTD Upper Beles Storage I
fij; UBD-2-US/1
■fpfiml 1.00-120 guveMsncuuiT
pl UC COMPUTATION SHEET
U.
Soil
r**Uw SeOJon
P.OBm 2581
Addis Ab«be
Ethiopia
Sample type Undisturbed Test type Attertoerg Umtt Date 10/11/2010
(J**1 *_______
vTitw________
K/WW4 To wK
^furpt • T*9 pry
_________
n
r-<Mar
“   70   “ TT
34 070" 27.140 T93? 14.840 12 300~
56 341
U 337
16 37.890 29210
8 880
14 820
14 390
60.320
’tedesi
PL
PL
tel re Sio
55
251
iluRM • Tire wel
28 220
28210
Wlirw*Tirt dry
24.600
24.450
WJaite
3.620
3.760
’n
14.890
14.360
WjM
9.710
10.090
37 281
37.265
37 27
Result
LL     5830% PL  37  27% PI 21.03%1
Pm, rtFT MJM «TTTC M*+ HAMT
<1707*+
Tol 251 -116 - 18 55 1
Fax 251 • 116 - 61 53 71/61 06 98 e-mail w.w.da.e©ethk>netet
4501
i
Projecf  Nile  Irrigation  and  Drainage  Project Cbent:       Addis Geo Systems CO LTD Location Upper Belles Storage I
BH  No  :  UBD-6-US/1 Depth (m): 100-1.20
LIQUCAND PLASTIC LIMIT DETERMINATIONS
DATA ANO COMPUTATION SHEET
Water Works Design and
Supervision Ente-rpr „—«is-e>— - ' r..^Cen
Laboratory Service SdU&xMateriW Testing Sec®.
P.O.Box 2561
Addle Ababa
Ethiopia
Sample type Undisturbed Test   type   Atterberg   Limit Date 10/11/2010
Type of test
PL
Pt
1
Container No
147
52
VT of samp* ♦ Tero wX
29.750
“29.770
W o< sample ♦ Tare ary
25.910
25.830
Wo<wilr
3840
3 940
Tare
15.380
15010
wt of dry sori
10.530
10.820
Water conleni %
36.46”
36 414
36 44
Flow curve
j
I
J
I
!
Result
L L 56 05% PL 36.44%
19.61%
Tested By Checked By Approved By
4
'1
■J
II JJtW? *TTTC
•PjL.
'"inn*
251 • 116 - 16 55 16/61 45 01
251 -116-61 53 71/61 08 98
w.ird • •©*fMonet.<rt
»v.u.
Hie Irrigation and Drainage Project
1^
>
AMs Geo
Geo Systems CO LTD
Upper
Belles Storage I
Water Works Design and Supervision Enterprise Central
Laboratory Service Soil & Material Testing Section
POBox 2561
Addis Ababa
Ethiopia
Sample type Undslurted Test type Atterberg Limit Date 10/11/2010
a* ■* iaiflv
UBM-US/2
340-3 85
.. PLASTIC IMT
ifA^OhS
yVMC COMPUTATION SHEET
raw*' FUTk»
LL
141
LL
361
LL
“ 528
30
~22~
16
» Taraj*^
34 390
35 9CC
36 920
29 220
30 270
30770
5.17C
5.630
6 150
14 640
15 160
14.890
14.580
15 110
15 880
*
34.245
35.460
37.260
38 728
PL
PL
CrrxiHc
53
187
^Jiircw ♦ Tan we*
29 830
29 81ft
* Tan dry
26.630
26 480
3 200
3.330
*n
15 06C
14 600
•frrrywi
11.570
11 800
27 658
28 030
27 84
Result
LL      3438% PL     27.84% PI 654%
f1
I
Wl IUH NUM 4TTTC
KIH 1WTC
kWTH
'
p.
1 %i
Water Works Design and Supewteion Enterprise Central
Laboratory Sendee
'7 . Soil & Mortal Testing Section
Tel 251- 116 -18 55 16/81 45*01             POBcx 2561
1
*
I
Fax. 251 -116 - 81 53 71/61 08 88 KMil w.w.d.s.eQethionetet
Project. Nie irrigation and Drainage Project Client:    Addis Geo Systems CO LTD Location Upper Bettes Storage I
1    BH No. UBD-7-US/1 c   Oeptr (m). 1.20-1.45
UQUID ANO PLASTIC LIMIT
Addis Ababa
Ethiopia
Sample type. Undisturbed Test type Atterberg Limit
Date 10I11Q010
\
1
.I
4
DETERMINATIONS
DATA AM) COMPUTATION SHEET
frypt o# test
~
r
PL
iCornmw He
168 |
319
bMotumole * Titewtrt
26 316 1
28.300
IWId wmplt* Tin dry
24.370 |
24.170
nMotwaer
3.950
4.130
I Tan
15.370
14 860
|*A of dry sort
9000
9310
ftater ortantX
I 43.889
44 361
44.12
Ftowcunn
1
1
I
I
111.000 !
* HO MO ■
J 1W000
5 100.000
t 107 000
11 os 000
1 105000
104 000
Result
I L 107 95%.
PL 44 12%
PI 63 83%
1
1
Tested
1
i
I
Checked B^
*WovedByauction
10 ln^               Summery of laboratory test result of soils taken from Upper Belles T hisfepOft ?rf) Sit® ”                  A of feasibility study for Nile Irrigation and Drainage project. The
, are Gram S'
. l0oge da
Analysis, Atterberg Limit, Linear Shrinkage, Natural Moisture
jesi re50S'1 ulphate Con e     t water extract from soil and Dispersion test by Pin Hole The
Contflafni'vsis are 030100
f.f Stan dard Procedures so’ana y
-ere i"
‘ GrairTSize Analysis Atterberg Limit Linear Shnnkage
following the appropnate sample preparation and testing ,_rH Drocedure followed to carry out the analysis is presented
Standard
BS Test 7(B)
f
5
Natural Moisture Content
Sulphate Content water extract from Dispersion test by Pin Hole
W
Linear Shnnkage
Turbidity Meter Method Berard eTaT(l 976)I
Parameters
UBD4
(0.30-1.(Him) S.No-1
Nile Irrigation and Drainage Project (Lipper Beles Storage Dam)
Summary of Test Results
Date: 11/01/2011
UBD4 (1.00-4.00m)
S.No-2
UBD4       T (6.30-7.00m)
S.No-3
UBD4
(9.00-9.50m) S.No-4
UBD4 (13.00-14.00m)
S.No-2
UBD4 (17.80-18.25m)
S.No-6
Grain Size Analysis
Clay %
Silt %
Sand %
Gravel %
12.00
16.79
8.48
62.73
9.00
27.22
14.45
4933
2.00
2.69
57.67
37.64
30.00
37.66
11.49
20.85
44.50
52.01
3.49
-
7.00
75.91
17.09
-
Atterberg Limit
Liquid limit %
Plastic Limit %
Plasticity Index %
-
•
-
20.35
17.20
3.15
67.97
28.89
39.08
72.60
33.35
39.25
•
-
Linear Shrinkage (%)
-
-
-
20.36
20.54
____________________
1 Natural Moisture Content (%)
-4
-
•
:
I
1
1 . -1
__
1
| Sulphate Content water 1 extract from coil (meq /1)
-
30.55
1            ■ 1          ~ /
I
1 Dispersion test by Pin Hole 1__ I
ND!
NDr
.         ND!   J    ND<          ■
L
____
Ss* -t
1fVilc frrigataon anil Drainugc Project
r~"     S.No-7
(Upper Beles Storage Dam)
Summary of Teat Results
Date: 08/12/2010
1    UBD4
(21.30-2230m)
UBD4 (26.20-26.60m)
S.No-8
UBD4                  UBD4                UBD4                   VBD4             \ (29.40-30.00m) 1 (1.00-1.45m) \(  (10.00-10.45m)    ( ll.90-n.35m)
S.No-9                 SPT-3 < i           SPT-2                     SPT-1
1  Grain Size Analysis
Clay %
Silt %
Sand %
Gravel %
1.64
13.46
23.80
61.10
5 50
32.66
45.23
16.61
15.00                      49.98                       16.50
7.00
36.86                      47.36                       81.50                        17.82           |
48.14
-
2.66                         2.00                          13.87
-
-
61.31
Attcrberg Limit
Liquid limit %
Plastic Limit %
Plasticity Index %
-
•
-
-
-
-
51.42
29.03
22.39
•
77.28 74.28 32.08 37.23 45.20 37.02
Linear Shrinkage (%)
•
SB
•
13.57
23.21
21.07
Natural Moisture Content (%)
•
-
-
27.25
33.18
42.24
Sulphate Content water extract from soil (meq / 1)
■
•
•
■
-
33.18
Dispersion test by Pin Hole
ND,
___________
-
ND.
--------
ND.
ND.
-
ND- Non Dispersive
Checked By Approved By Nile Irrigation and Drainage Project (Upper Belcs Storage Dam)
Summary of Test Results Date: 08/12/2010
Parameters
UBD4
(5.40-6.00m) S.No-1
UBD5
(6.60-7.00m)
S.No-2
UBD5 (8.00-10.00tn)
UBD5 (1.00.1.45m)
S.No-8
UBD5
(2.90-335m)
S.No-9
Grain Size Analysis Clay %
Silt % Sand % Gravel %
3.50
8.82
49.01
38.67
0.44                   Fine Gravel        0.08% 7.52                   Medium Gravel 3.13%
35.07                   Coarse Gravel 96.79% 56.97
4.00
11.32
8.18
76.50
9.50
16.11
10.37
64.02
Atterberg Limit Liquid limit % Plastic Limit % Plasticity Index %
•
•
•
28.72
18.87
9.85
-
-
Linear Shrinkage (•/•)
-
-
1
1
Natural Moisture Content (%)
Sulphate Content water
' extract from *oil( meq /1)
Dispersion test by Pin Hole
•
-
■ 1    20.66
-
63.33
32.01
31.32           |
26.90
_____________ 1 32.97          I
_ •
1
- -C<
S'*
1
■ I
ND,  1 nd4Water Works Design and
. Supervision Enterprise Laboratory
Service
^ Drainage Project(Upp
er Betas Storage Dam)
^”8PK
SC_a_m_ 1. No: 1
(S
Sam. Type: Disturbed
^ B*S
Test Type : Wet Sieve + Hydrometer
UBO*
Date : 15/12/10
Total mass ojiamplt Rrfon vaih . j
Tntal man of tempi' Afttf Hash , g
r X«»»/
H TmTq) 12QJ-W
~7i9l20 718.50
M f' *" *
Rr/
.
Man o f
Rif. soil fa)
1800.00
1205 H>
586.10
"59840
57810
236
1H
060
dfO
035
(M
pan
srcnc jf /■___
t
53300
551.10
538.90
516.70
488.20
48190
459.20
1087.80
1224.20
791.50 O Z£9I t.fiUf)
~~608.40
605 10
543.50
551.10
546.90
522.20
492.70
486.40
462.20
0.00
000
0.00
H 00
75.00
35.00
10.00
27.00
10.50
0.00
8.00
5.50
4.50
4.50
3.00
P'rrrntage Attain'd
0.00
0.00
0.00
10 98
24.29 11.65
3.33
8.99
3.49
0.00
2.66
1.83
1.50
1.50
1.00
% Rftent'd
0.00
0.00
0.00
1098
55.27 46.92
50.25
59.23
6273
6273
65.39
67.22
68.72
7022
71.21
300.50 214.00
Pmntegf Pairing
100.00
10000
10000 8902 64.73
33.08
49.75
40.77
37.27
37.27
3461
52.78
31.28
29.78
28.79
425.50
512.00
86 50
28.79
100.00
0.00
2.&4
Tfriprafurr
Test Temperature, deg.c 22
Artmtl Hjdtnntttfr
370000
MOW 320000
20.0
20 0
20,0
20.0
20.0
Corrtcud
f lydromttrr
Rtadiiig
30.0000
27.0000 250000
23.0000
19,0000
17.5000
14.0000
11.90
12.20
12.50
13.20
Cotffidtnt K
0.01293
0.01293
0.01293
0.01293
0.01293
Gnuii
Jqr
0.0309 0.0199 0.0117 00083 0.0061
13.40
.'Wai?, o.oojo
Ptnmlagt
Filter
Combined
22.15 19,93 18.45 16.98 14.03 1292 10.33now rtf* mum *ttc ire
MPt+A »w
S °H 4 Material Project Hie Irrigation and Drainage ProjectfUpper Bales Sto --------------------
Jraoe Dam\
Tt '
na/ 1
Ghent:      Addis Geesystems Pic Location : Upper Befes 
BHNo. UBCM Depthfm): 030-1.00
-Sam. No ; 1             Dam)
Sam Type: Disturbed Test Type Combined Date; 15/12/10
Graph
Grain Size Distribution Curva.BS
10 1 0.1 0.01
Grain Srze<r
im)
Gravel
Sand
Silt                  L
Ttrttdb) -/-—-J-farr Cb'dudbj:__-^7Vater Works Design and Supervision Enterprise Laboratory Service
’d Damage Projed(Upper Beles Storage Dam)
an**
P,C
5^;_ JpP«r^s uBtH
!■* .JOM.00
rS_u__n.xiN_o. : 2
Sam. Type : Disturbed
Test Type : Wet Sieve * Hydrometer Date: 15/12/10
’/Wiwn of
Total mass oj
Mass of
ty* nvjh, g
■'tyrr »Z
Percmtagr
Cnmvlafiw
185.50 135.00
Perrtfttag
Ref. jri/(g}
% Re tamed
Poising
1800.00
120350
0.00
0.00
Retained
0.00
0.00
100.00
1087^0
0.00
0.00
0.00
0.00
54.00
19.50
0.00
0.00
0.00
0.00
100.00
100.00
1191 20
0.00
0.00
100.00
718.50
586.10
652.40
597.60
551.00
0.00
' 100.00
378.10
333.00
551.10
538.90
516.70
488.20
481.90
459.20 425 50
551 10
550.90
18.00
0.00
12(H)
0.00
29.11
10.51
9.70
0.00
6.47
5.93
0.00
0.00
2911
39,62
49.33
4933
55.80
527.7Q
495 70
11.00
750
6.50
404
61.73
65.77
488.40
465.70
6 50
476,00
50.50
5.50
3.50
27.22
6927
72.78
100.00
10000
70,89
6038
50.67 50.67 4420
38.27 34.23 30.73 27.22
0.00
2.73
Tenprafirre
Tut
firry, deg c 2
Corrected Hydrometer
Reading
25.0000
Coefficient
K
0
Gmm
{'mm) 0.0329 0.0211
Pmmtage
Hjdrvmtfir
AM^M
^310000^ 29.0000
de^.c
Finer
Combaed
20.0
20.0
23.0000
20.0000
0.01334
0.01334
0.01334
0.01334
0.0124 '
18.0000
0.0089 ’
15.0000
0.013
22.0
20.0
12 0000
21.63
19.90
17.30
15.57
12.98
10)8
100000S “P«rvW  *0^
o
r
■S I
i
m rtFl JiHins ,t»TTC jrc£
Proicct:  Nite  Irrigation  and  Drainage Client:       Addis Geosystems Pic
Location: UpperBeles
BH No. UBCM Depth(m): 1.00-4.00
Sam. No : 2
Sam. Type : Disturbed Test Type ; Combined Date: 15/12/10
Graph
i
!
I■ J
■I
I ”1
j ->
I J
I
j
!
9i
TtJlcJ b ••____ ' TT1 Cbtchd by •_
I1Water Works Design and Supervision Enterprise Laboratory
Service
4, ,.....
. Drainage Project(Upper Beles Storage Dam)
^i^’u"aPK
Pk;
> ^rBeles
Saw. No: 3
Sam. Type: Disrvrbcd
'fest Type : Wet Sieve 4- Hydrometer Date: 15/12/10
Toto/ mass of samplt Btfen wash, p
Tata/mass of samp/t After wash, p
MOSS of
i R/A son' £
1800.00
1087.80
59840 578.10 53300 551.10 538.90 516.70 488.20 481.90 459 20 42550
Aifad
3wnn<tfr
605.60 606.40 589.10 545.50 551.10 551.90
535.20
508.20
404  40
46470
44050
2.82 leftp nt fart
dejf.c
OOP
0.00
0.00
0.00
0.00
19.50
8.00
11.00
12.50
0.00 1300 18.50
20.00
12.50
5.50
15.00
Pentntogt CMulatwe Pa/aifitd
0.00
0.00
0.00
0.00
0.00
14.39
5 90
OOP 000 OOP 0.00
0.00
14.39
20.30
8.12 9.23 0.00 959
15.65 14,76
9.25 4.06
11.07
28.41 3764
37 64 " 4723 ’ 60.89 ~ 75.65 " 84.87 " 88.93 "
100.00 [
135.50 120.50
Pen'tnfape Pasrrnp
100.00 100.00 10000
100,00
100.00
85.61
79.70
71.59
62.36
62.36
52.77
39.11 2435
15.13 11,07
0.00
Ttst Ternperafare, dtp
7wr
Comrttd
Hydrvmt/tr
Effective
Depth
(rm)
Cerfineat
t       20 dnufi
Fmtr
mm) Cambtmd
20.0
16.0000
11.0000
9.0000
7.5000
6.0000
4.0000
14.50
14,80
15.10
15.50
15.60
0.01300
0.01300
0.01300
0.01300
0.01300
3.5000
2.0000
15.70
16.00
0.0350
00224
0.0150
0.0093
0.0066
0.0032
" a/.
* //^ -
V \\ b
V. ^.‘JCcirr 5t
nnH
HTTC
I 3“Perv!.lon E
„^9n
'<
5
Service
Project
: T Nile
w Draina
ge Pro|Kt(Upper Beta,
Stoia/A"’"^' r««  ,.«
n<
Client:
iAda
s Geosystems PIC
Sun No 3
°
’**'
Location. Upper Boles BH-No. UBO-4 Deprh(m): 6.30-7.00
Sam. Type ■ Disturbed
1 cat Type Combined Granh
n*te: 15/ :12/i
0             **
Tsrtft/ fy ; Z^f
Checked jrf
»• •
>• . *
< X-i'W 5
x\ V z' -Vj <*•.•jnd JWater Works Design and
Supervision Enterprise
Laboratory Service
Drainag  Project( Upper Betes Storage Dam)
e
**“ items P,c
Sam No : 4
Sam. Type Du curbed
Test  Type  Wet  Sieve  +  Hydrometer Date: 13/12/10
Total mass of lamplt Btfon wash, £
of sampU Aftrrwash, g
1800.00
Total mass < Mass of
Rtf. soil @
0.00
Pentatapr Rtldimd
0.00
GMvhtrrr % Pa taint 8
0.00
23500 76.00
Pemnfage Passing
10000
0.00
0.00
0.00
0.00
0.00
0.00
0.00
000\
100.00
10000\
597.10
[90
586.10
533.00 55110 538.901
555.50
551.10
552.40
11.00
7.50
8.00
2250
0.00
0.00
0.00
4.68
7.87
1128
20.85
20.85
100.00
100.00\
9532
92.13
88.72
79.15
79.15
13.50
26.60 '
516.70
488.20
523.20
490.20
6.50
2.00
0.00
0.00
4.68
3.19
3.40
9.57
0.00
5.74
2.77
0.85
2936 '
7340
7064
30.21 "
69.79
481.90
45920
425.50
484,90
461,20
584.50
3.00
2.00
159.001
1.28
0.85
31.49 “
32.34 ~
68.51
67.66
67.66 '
ioooo[
0.00
Tut TemptratoTr, 4/g
Tfnprj/t.rt |
I
HyhiKirr Kfdartg
430000 38.0000
Tlffectivt
Depth
20.0
20.0
Corrtcftd Hydrofncttr
37,0000
32,0000
c      20 Gnua
1020       0.01318          0.0298
11.10        0.01318
0.0196            55.30
20.0
20.0
29.0000
26.0000
11.50
12 00
0.01318
0.01318
0.0115
0.0083
24,0000
i^oooo
16.0000
12.40
0.01318 \
13.20\
0.01289\
00060
0.0030
50,11
44.93
41.47
32.83
0.0013
27.65)
i
nm-i rvrt Jinn'; *ttc
Water Works Design;
jrc#+ MPtH *w
Supervision Enterpn
Laboratory Service
_ <5t T~»z'» Project: Nile imgaton and Drainage Project)Upper Beles Storage
Soil & Material Testing St
i
O
r'-"1
”Sim. No : 4
Sam Type : Disturbed
<
Client. Location
Addis Geosystems Pic Upper Betas
^®nt)
BH   No.   UBD-4 Dcpih(m): 9.00-9 50
Test Type . Combined Graph
Dale: 09/11/10
?
I,KS
ns           *i"[c
r1
t MA’’**
Water Works Design and Supervision Enterprise Laboratory
Service
Toting s^ctibn^ b
Total v
projec((Upper Betes Storage Dam) Sam. No: 5
Sam. Type: Disturbed Test Type : Hydrometer Dace: 15/12/10
f sample, g                 50
551.10
5)8.90
459.20
2.67
551.10 539.20 517.15 488.57 482.23 459.48 \
0.00
• Mass of
)
0.00
0.30
0.45
0.37 0.33 0.28 0.00
Ptrtnto# Retaiited
CMftfulatnr
% R/£tJr**/
0.00
0.61
0.91
0.75
0.67
0.57
0.00
Tut Ttrnpenifan, dq.:
0.00 0.61 132 2.26 2.93 3.49 0.00
20
Pmmtaff Pacing
100.00
99.39
98.43
97.74
97.07 9651
000
Effective
Depth
(<*)
Coefiatnt
Gnu it
jb J tronmrter
TtnprjtapL
*8‘
Corrected
Hydrometer
St^t
Penrntagf
Filter
1W1
Rea dr
mm
Combated
4 425000
7 40.5000
20.0
35.5000
10.50
0.01357
0.0311
7628
if         15.0000 Jl.OWO
20.0
20.0
20.0
20.0
33.5000
30.5000
'28.0000
24.0000
10.80
11.30
11.70
12.40
0.01357
0.01357
0.0135?
0.01357
30
’W
285000
25.0000
22.0
20.0
22.5000
12.60
0.01327
0.0199
0.0113
0.0085
0.0062
0.0030
71.93
6553
60.16
51.57
43.35
18.0000
13.30
0.01357
0.0013
33.68nan rtPT *ttc tnntH moiih
Mxr jfWWiJf
, Wator Works Dea,
i supervision Enterp*?? ’nd
ServICe Lab°r
Project; Nile Irrigation and Drainage Project(Upper 8eles Storage Dam)
Sec^
Client:          Addis Geosyslems Pic Loauon Upper Beles
BH-No UBD-4
Depth(m) 17.80-18-25
Sam. No : 6
Sam.    Type    :    Disturbed
Test L*vpe : 1 lydrometer
Date: 13/12/10
Tola/ mass ofsamph, 50
Sieve
No
Stevt
Mass    of S*t*(&
ass of ntvt Kr/ .soi/fgj
Mass of Hr/, soil (gj
Pentfrtajp Retained
CnmnUtj^   T % Rr/aj/rrJ
Penctnta#
No 10
2.00
551.10
551.10
0.00
0.00
No 16
1.18
558 90
544.07
5.17
5.82
0 00
3.82
9 A IQ
No JO
0.60
516.70
527.90
11.20
827
12.08
87 09
No 50
0.30
488.20
492.85
4.65
3.42
15.50
No 100
0.15
481 90
483.26
1.56
1.00
16JO
No 200
0.08
459.20
460.00
0.80
8) 50
0.59
17.09
/ui/r
.
82 91
0.00
0.00
0.00
0.00
0 00
.
Sptafi: Gnn     TO OJlOii
2.84
Tort Trrnptnrtvrr, dtg c 20
Eiapttd
Ttmt
(mini
Artrnsl 1  [ydnmtUr
Tenpnrtttn
**'
Corrected
J fydnumeler Reading
Ejffrcthn
Depth
(cm)
Coeffiaenl
K
Gram
irrrrn)
Pervrnfaft
Fi*r
Corrrbimd
2
25.5000
20.0
18.5000
15.20
0.01293
0.0332
36.16
5
25.0000
20.0
16.0000
13.70
0.01293
0.0214
31.27
/5
20.0000
20.0
15.0000
14.20
0.01293
0.0126
25.41
JO
18.0000
20.0
11.0000
14.50
0.01293
0.0090
21.50
60
16.0000
20.0
9.0000
14.80
0.01293
0.0064
17.59
250
12.0000
22.0
6.0000
15.30
0.01264
0.0031
11.73
1440
8.0000
20.0
1.0000
16.10
0.01293
0.0014
1.95
Grain Size Distribution Curvs.BS
100 00
90 00
80 00
70 00
60 00
50 00
4C0C
10 00
20.00
1000
000
TeriW b)Vittet Works Design and Supervision Enterprise
Laboratory Service
So//4 Material Testing Section
Pro)ect(Upper Beies Storage Dam)
Sam- No: 7
Sam. Type: Disturbed
Test Type : Wet Sieve + Hydrometer Date: 12/12/10
Mau of
Ptrctttagt Pj tamed
Camubtiee
% Rftamed
0.00
0.00
o.oo
1087.80
0.00
0.00
0.00
149.50
0.00
53.11
0.00
2.13
53890 516.70 488.20 481.90 45920 425.50
• Xn. jC70 jf m/
Actual
602.40 585.10 5J8.50 551.10 552.90 545.20
500 70 48990 46320 468.00
2.72 Tertpralur*
df^.c
7.00 5.50 0.00
14.0) 28.50 12.50
8.00
4.00
42.50
Correctea Hydrometer
Reading 14,5000
13,0000
10.0000
8.5000
70000 3.0000 2.0000
2.49
0.00
0.00
0.00
53.11
53.11
5524
56.66
59.15
195
0.00
4.97
61.10
61.10
66.07
10.12
4.44
2.84
1.42
1510
7620
80.64
83.48
84 90 100.00
Tut Temperature, de&i
Henefer Rud&ii
20.5000
J
^JlPOOQ
'50000 f4 50oo
Effictme Depth
/ ’cm> 13.90
14.20
14,70
14.90
1520 15,80 16.00
Coefficient K
0.01337
0.01337
0.01337
0.01337
0.01337
001307
(L
281.50 239.00
Ptrrtftfagf Pattm^
100.00
100.00
100.00
46.89
46.89
44,76
43.34
40.85
38.90
38.90
33.93
23.80 19.36 16.52 1510 0.00
c 20
Cmm
(mm
0.0352 0,0225 0.0132 0.0094 O.OOtf 0.0033
PeewUdgt
Fmcr
Censed
9.53
8.54
6.57
5.59
4.60
1.97
1.31
iDOM WT                       *TTC
Project;
Cheat:
Luciaon:
BII-No.
&
1(      M, Beta Storage
N* Imsaloc .no Grata). P.o,ec  Up
'*ator Work,
Soil t ^?‘tory Ser??
r«»„„
Addis Geosystems Pic Upper Beles
UBD-4
Sim No: 7 
Sim. Type Disturbed
>
9S *
:
Depch(m): 21.30-22 30
Type: Combined C,nph
D«e: 12/12/10 PhO ne^ *‘ ’
r rr‘
Water Works Design and
Supervision Enterprise
Laboratory Service
/ jpperBe*’
r .        » at J iT
projecttUpper Beles Storage Dam)
Sam No: 8
Sam Type: Disturbed
T«t Type Wcc Sieve * Hydrometer Date 13/12/10
Man of Parfxtagt
Rftauxd
CtamdOnt
% Refined
14150 87.50
Pernntotf
PdJJinjr
0.00
0.00
0.00
0.0<f
0.00
22.00
598.40
0.00
0.00
0.00
0.00
0.00
0.00
1555
0.00
0.71
0.35
0.00
0.00
0.00
0.00
0.00
15.55
15.55
1625
16.61
558.90
541.40
2.50
526 20
507.20
506.90
9.50
19.00
25.00
8.00
13.43
17.67
5.65
16.61
18.37
25.09
38.52
56.18
10000
100.00
100.00
100.00
100.00
84.45
84.45
83.75
8339
83.39
81.63
74.91
61.48
43.82
459.20
425.50
467.20
479.50
2.75
54.00
38.16
61.84
100.00
Tut
4^ K
38.16
000
20
'-dd
r*
-IrtM/
Tf*prat*re
Corrected Hydrvmctrr
Reading
12.0000
Effective
I
Depth
Cxffiafti
K
Gmr/i
5qr
RfaMTff/
19.0000
20.0
(cm)
14.30
0.01325
170000
20.0
20.0
20,0
20.0
10.0000
8.0000
7.Q0QQ
6.5000
4 5000
14.70
15.00
15.20
15.20
15.50
001325
001325
mm)
0.0354 0.0227
[5.0000 ^40000 [55O0O_
0.01325
0.01325
aoi3Qj
0,0133
0.0094
0.0067
'Koooo
'^0000
21.0
20.0
Pcmnteg
Finer Combimd
22.12
18.43
14J4*
12.90
11.98
8.29
2.0000
16.00
$'401325
s ■! \\non w* W> t”TTC Mxr ;frntfK
. • |finxtn & .?aY^?
5
p ro1K1 Nile Irrigation and Drainage Project(Upper Beles Storage Dam)
Storaa<* n ^ - ’
a
Client
Addis Geosystems Pic
London Upper Beles
BH No. UBD-4
Depth fm): 26.20 26.60
Sam. No ; 8
Sam. Type : Disturbed
Test Type : Combined Graph
Date: 13/12/10♦ttc
!?*
Water Works Design and
Supervision Enterprise Laboratory
Service
Soil 4 Material Testing Section
and Drainage Project(Upper Beles Storage Dam) r  Nile Irrigation and Dramat
Addis Geosystems Pic
UPP*Beles UBD-4
^•29.40-30 00
T>0t»W *
Sam. No: 9
Sam Type Disturbed
Test Type Hydrometer
Date ; 13/12/10
i VW
! Mzir r /)y■
»
50
N*
Jm*
W*gf**J
Most  of Siet*(g)
551 10
f«l/J of JtfPt
RM joiifa) 551.10
— v a
Matt of
Ret. toil ft
0.00
Percentage
Retained
o.oo
Cumulative % Retained
0.00
Perrtnlage
Pairing
100.00
1.18
538 90
539.86
0.96
1.93
1.93
98.07
"5775
0 60
516.70
525.84
7.14
14.37
16.31
83.69
0.30
488.20
498.58
10 38
20.90
37.21
62.79
0.15
481.90
485.63
3.73
7J1
44.72
55.28
‘'N.W
0.08
459.20
460.90
1.70
342
48.14
51 86
Hr-
0.00
0 00
0.00
000
0.00
jtea>- Gratify twl
2.83
Tut lcMptru/urr,                          20
1'ffTpra/urr
Tiw
mJ
Actual
I Ijd/vmfter
R/adig
Corrected
/ lydrvrneter
Effertne
Depth
(cm)
Coefficient
K
Crmn
(””)
Percentage
Finer
Combined
2
27 0000
20.0
20.0000
15.00
001297
0 0331
38.77
5
25.0000
20.0
18.0000
13.30
0.01297
0.0212
34.89
15
22.0000
20.0
15.0000
13.80
0.01297
0.0124
29.08
30
200000
20.0
13.0000
14.20
0.01297
0 0089
25.20
60
19.0000
20.0
12.0000
14.30
0.01297
0.0063
23.26
250
15 0000
22.0
94)000
14.80
0.01267
0.0031
17.45
1640
13.0000
20.0
6.0000
15.30
0.01297
0.0013
11.63
Grain St» Distribution Curve, BSI
m rtPT w; ♦ttc jrcfrb PMi-H A7tnn-f \ rxcr/W’/K' WM ?
Project: Nile Irrigation and Drainage ProjectfUpper Beles sr
Water Works Design and Supervision Enterprise
Laboratory Service SoO Material Testing Section ,
I
□lent:         Addis Geosystems Pic 
Location: Upper Betas Bl I No UBD-4
Depthfmj 1.00-1 45
Sam. No: SPT-3
- - ------------  fa9e °arn) *
Sam. Type : Disturbed Test Type : 1 lydromctcr
Date: 15/12/10
Total mas s of sample g 
50
Sieve
No
SlfTt
Mass    of Sievtfa/
lass oj sieit Ret .soil(y
Mars of Ret. sotl fa)
Percentage Retained
No 10
2.00
551.10
551.10
0.00
0.00
Catmuiat™ % Retained
OSH)
Percentage _ Passing
10000
Nt 16
1.18
538.90
539.09
0.19
0.40
0.40
99 60
No JO
0.60
516.70
516.83
0.13
0.28
0.68
.
99A?
No 50
0.30
488.20
488.35
0.15
0.32
1.00
99.00
No 100
0.15
481.90
482.20
0.30
0.64
1.64
98.56
No 200
0.08
459.20
459.68
0.48
1.02
2.66
97.54
pan
0.00
0 00
0.00
000
0.00
Specific G rarity of soil
2.83
Tert Temperature, deg.c 20
Elapsed
Time
mini
Actual Hydrometer
R/Jdrnf
Teapruture
Corrvr/ed Hydrometer Reading
Effect™
Depth
(<*)
Coefficient
K
Gram
Si^e
(mm)
Percentage Finer
Combined
2
490000
20.0
42.0000
9.40
0.01297
0.0281
85.92
5
46.5000
20.0
39.5000
9.80
0.01297
0.0182
80.80
15
43.0000
20.0
36.0000
10.40
0.01297
0.0108
73.64
30
40.0000
20.0
33.0000
10.90
0.01297
0.0078
67.51
60
35.0000
20.0
28.0000
11 70
0.01297
0.0057
57.28
250
32.0000
22.0
26.0000
12.00
0.01267
0.0028
53.19
1440
28.0000
20.0
21.0000
12.90
0.01297
0.0012
4296
Grain Size Distribution Curve,B5
;     100.00
V     90.00
?   80   00
E   70   00
•   60   00
?     50 00
t      40.00
5  3000
£ 2000
a. 1000
000
0 0001
10
Gravel
1
_______ Grain
Sand
0.1
Tested by* 
Checked by:
•_!*t«
fir*
r - » •’F
Water Works Design and
Supervision Enterprise
Laboratory Service
SoH.^MattrlalTosting Section
and Drainage Project(Upper Beles Storage Dam)
if           N^|rnga"°n
Addis Geosyslems Pic ^pperBeies
ubcm
iy,oo-io45
Sam. No SPT-2
Sim. Type: Disturbed
Test Type: Hydrometer
Dire: 13/12/10
Total masi </ tumpk x$0
i 1 rf
'
"5^"
ft#
r
2fi0
1.16
Marr   of SiM$
551.10
{dJf OjjtfTt
R/t jw/|X
Mau of
Rr/. W (g)
Prrmtagr
Pairing
551.10
538.90
0.60
O.3O
0.15
516.70
48820
481.90
0.08
45920
539.01
516.93
48832
482.13
459.49
0.00
0.00
0.11
0.22
0.12
0.23
0.29
0.00
Parmtdgf
Rflaiwi
000
0.22
0.47
025
0.47
059
000
CtnKtdatM
% PjUmtd
0.00
022
0.69
0.94
1.41
2.00
100.00]
99.78
9931
99.06
9859
98.00
0.00
0.00
/.fen. 6/wfi ?/r
w/ 2.73
Tut Ttnrptralwr, deg t 20
1 E^utd
1w
2
Actoai Hydmmfcr
R/adw
Te/rtwtMn
Effrrtnt
Drptb
>/
Cotffiamt
K
445000
L2
43.0000
1v
40.0000
20.0
20.0
20.0
P--
1 60 L 30
375000
260000
31.0000
20.0
200
22.0
Comcttd Hydrwacftr
R/jihrf
37.5000
36.0000
33.0000
30.5000
29.0000
25.0000
10.10
10.40
10 90
11.30
11.50
12.20
0.01334
0.01)34
0.01334
0.01334
0.01354
0.01503
Gram
Siqt
fan)
0.0300
0.0192
0.0114
0.0082
0.0058
0.0029
27.5000
20.0
20.5000
12.90
0.01334
0.0013
Ptmntagt
Fmrr
Combmid
75.30
7229
66.27
61.25
58.23
5020
41.17
? 100 00 . r Woo
Grain Sot attribution Cum.BS
- ♦ . f . » * h^jtj-----;:ni.
zizur»
1
i
I
non W* MW *T,rc jtcJH- pnntfi ftioifr’f
Water Works
Su Pervision E^9n and
Moratory
:x .‘
:
So ^M
afcrfa/
7
fi
S ^ice
Project:
Client
Nile  irrigation  and  Drainage  ProjectfUpper  Beles  Storage  Da"™*
,R —
Addis Geosystems Pic 
Ixxitioo Upper Beles BH-No. UBD-4 Deptbfm): 11.90-1135
Sim. No: SPT-1
Sam. Type : Disturbed Test Type: Wet SleVe + Hvdr IDWaltUeB:/1in5/12/10
Total man of lamp!/ Brfarr snub, Total mass of santttlt Afttr
.J...
—.
7 ncTc*
68.50
Sit*
Ofifttttfnnn,
Man  of
5ieie(g)
Ifj j oj ntvt
Rft.ldty
Mass of Ret. toil fa)
Ptntnla#
Retained
Cumaiatrn % Retained
75.00
1800.00
180000
0.00
0.00
sow
0.00
1203.50
1203.50
0.00
__ 51.50 Ptrnnidgt
Passtnp 100 00
0.00
0.00
37.50
10!7.!0
10S7.S0
0.00
o.oo
. 100 00
0.00
25.00
1191.20
119120
. ZOOM
0.00
0.00
0.00
19.00
718.50
738.50
lOO.oi)
20.00
29.20
29.20
12.50
586.10
594.60
8.50
70 80
12.41
41.61
9.50
598.40
598.40
58 39
0.00
0.00
41.61
4.75
578.10
58 39
587.10
9.00
13.14
54.74
236
533.00
. 4526
537.50
4.50
6.57
6131
2.00
551.10
38 69
551.10
0.00
0.00
6131
1.18
538.90
541.90
.
38^69
3.00
438
65.69
0.60
516.70
1431
519.20
2.50
3.65
0.30
69.34
488.20
30 66
490.20
2.00
2.92
0.15
72.26
481.90
27 74
482.90
1.00
1.46
0.0!
73.72
459.20
.
26 28
460.20
1.00
PAN
1.46
75.18
425.50
.
24 82
442.50
17.00
24.82
5peafi: Grau
100 00
Oj IM
.
0 00
2.76
.
Test Tanperjiurr, dei
.
hiapsed
Time
(min)
|X- —u
Coefficient
X
c 20
Actual
Hydrometer Reads
Tnpratxrr
Corrected / lydnmeter Reading
2
Effective
Depth
'em)
Grain
Sup
(mm
Percent*# Piner
Combined
2 S.0000
20.0
21.0000
5
12.90
0.01322
0.0336
16.52
25.5000
20.0
IS.5000
13.20
0.01322
0.0215
14.55
15
23.0000
iv
20.0
16.0000
13.70
0.01322
0.0126
12.59
21.0000
(0
20.0
14.0000
14.00
0.01322
0.0090
11.01
n.oooo
20.0
11.0000
14 50
001322
0.0065
8.65
250
16.0000
22.0
1440
10.0000
.
14.70
0 01292
0.0031
7.87
14.0000
20.0
7.0000
15.20
.
0.01322
0.0014
5J1
r
I
»
i
♦
j
i&•!«■« * </»«*♦*
TT C
,
Water Works Design and Supervision Enterprise
Laboratory Service V ,z pdiriMattriAiTestfng Section
Geosyetems Pic
(X ‘ UpP  ®
er
eleS
U8D-4
' lWl255
ProjectfUpper Bales Storage Dam)
Sim. No: SPT-1
Sim. Type : Disturbed
Test Type : Combined Graph Date : 15/12/10
inow ww *ttc
JTCJt+ NHH hltllfrt
W «tar Works D...
Supervision E ?
nt
n ar”»
Laboratory
.1
.//..®...<..»..«..*...M_ ateria/?^*1*
Project: I
Nile Irrigation and Drainage Project(Upper Betas Storage Dam)      )
Client? Loci non BH-No.
Addis Geosystems Pic Upper Betas
UBD-5
Depth (m) 540-6.00
Sam. No: t
S«m Type: Disturbed
Test Type: Wet Sieve +! Ivdromcter Date: 15/12/10
Total mass of sample tyfon wash ,        203 00
Tola! mass of sample Afar wash. p       f 7u /v.
O
Steve
pmi^mmj
'
Mass of V Sitveyj
aiitfntve •
I
Mass of
ts. soil (gj
Percentage 1 Gmuteht p % Retained
75.00
1800.00
1800.00
0.00
0.00
000
frontage Pasnng
undo
50.00
1203.50
1203.50
0.00
0.00
0.00
10000
3730
1087.80
108780
0.00
0.00
0.00
wm\
25.00
1191.20
1191.20
0.00
0.00
0.00
/oo.oo
19.00
718.50
718.50
0.00
0.00
0.00
100.00
12.50
586.10
592.60
6.50
520
3.20
96.80
9.50
598.40
609.40
11.00
5.42
8.62
91.38
4.75
578.10
610.60
32.50
16.01
24.63
75.37
2.36
533.00
561.50
28.50
14.04
38.67
61.33
2.00
551.10
551.10
0.00
0.00
38.67
61.33
1.18
538.90
572.90
34.00
16.75
55.42
44.58
0.60
516.70
556.20
39.50
19.46
74.88
25.12
0.30
488.20
503.20
15.00
7.39
82.27
17.73
0.15
481.90
488.90
7.00
3.45
85.71
14.29
0.08
459.20
463.20
400
1.97
87.68
12.32
PAN
425.50
450.50
25.00
12.32
100.00
0.00
Speafic Gran/) of soil
2.79
Test Temperature, dtg.c 20
Elapsed
Actual
Tenprature
Corrected
Effect™
Coefficient
Grain
Percenup 1
Time
/wj
Hydrometer
R/oir^
*&c
i lydnsmettr
Reading
Depth
cm!
K
Si^e
(mm\
Finer
Combined
2
165000
20.0
9.500G
14.70
0.01311
0.035.
J           M6
5
15.0000
20.0
8.000C
15.0C
0.01311
0.022
7           755
15
14.0000
20.0
7.000C
15.20
)       0.01311
0.013
2 660
30
130000
20.0
6.0001
)            15.3(
0.01311
0.009
60
12.000C
20.0
5.000(
)            15.5(
]       0.0131
1 0.006
250
11.OOOC
22.0
5.0001
)             15.5i
) 0.012&
I-
4  3.66
7  V*
2  4.72
” *> 0 1
1440
10.00(K
20.0
3.0001
J            IM
3
i  •        '*72
,
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.
H 5 C Vr II ' 7Water Works Design and Supervision Enterprise
Laboratory Service
w*.
lW P>*’
» uBO-5
1^. 540-6.00
Sage ProieeH Upper Belas Storage Dam)
Sam. No: 1
Sam Type : Disturbed
Test Type Combined Graph
Date: 15/12/10
Grain Size Diatrfbution Curve,BS
I
I
I
I
II*
• ♦
I I
non WW *TTC
JTCH MUiJrH *101H
I
Project: Nile Irrigation and Drainage Project(Upper Bales Storage D
Water Works Design and Supervision Enterprise
Laboratory Service Soil i Material Testing Section
Client:
Addts Gensystems Pte
'
1
i
Location Upper Beles
Sam. No: 2
Sam Type . Disturbed
BH-No
UBO-5
Depth(m): 6 60-7 00
Teat Type: Wet Sieve + Hydrometer
Date B/12/10
Total matt of /ample before maik . &
Total maci of tample After ygjh , 
201.00
185.fin
Sine
Mau of U Siereig)
ajjefam    *    / R/f .ntty R
'darstf    I    i it toil (g)
^erctntag (
RrtaiJW $
nmulalirt o R/ tamed
^ementage ]
7500
1800.00
/SOO.GO        0.00
0.00
0.00
700.00]
50.00
1203.50
1203 50          0.00
0.00
0.00
/oooS]
37.50
1087.80
fO«7JO           0.00
0.00
0.00
foo.oo
25.00
1191.20
1191.20\              0.00
0.00
0.00
100.00
19.00
71850
769.00
50.50
25.12
25.12
?4.88
1250
586.10
596.60
10.50
5.22
30 35
69.65
950
598.40
606.90
850
4.23
34 58
65.421
4.75
578. W
600.60
2250
11.19
45.77
54.23
2.36
533.00
555.50
22.50
11.19
56.97
4303
2.00
551.10
551.10
000
0.00
56.97
4).03
1.18
538.90
563.90
25.00
12.44
69.40
30.60
0.6b
516.70
541.20
24.50
12.19
815$
18.41
0.3(
)        488 2C
501.20
13.00
6.47
88.0t
11.94
0.1
481,91
486.90
5.00
2.45
905
5               9.45
0.0
J 4592t
)         462.20
3.0C
1.4$
92.0
4                7.96
PA2
J 425.51
3         441.50
16.01
7.9(
5          100.0
0 0.00
Gncin of soil
Actual
I {ydromrfrr
RftJdtgf
13.0000
2.73
Tttyratkre
Contend Hydrometer
R/dJjr,
Tut Temperature de^c 20 ffectn* Coefficient ] Grain
Depth K
Si^t
I mm;
0.0369
Penentage Finer
Combined
20.0
6.00001
0.01334   \
12 0000
70.5000
20.0
20.0
5.0000
35000
0.01334
0.01334
0.0235
9 5000
8 5000
20.0
20.0
2.5000
1.5000
15 90}
16.00
0.01334
0.01334
0.0136
0.009?
70000
21.0
1.0000
16 10
0.01303
0.0069
0.0033
65000
21.0
0.5000
16.20
0.01334
Tejted by:
Checked by:* T'r n
i
Waterworks Design and Supervision Enterprise
Laboratory Service
■y .>
rCa,nage project upper Bales Storage Dam)
C^r^PIc
* JKX'8*"5 uBt> s
.SO’"0
...-.-ms r
S ™No:2
Sam Typ<>. i:hlturbcd
Test Type : Combined Graph Date: 13/12/10
d«'-3
Grain Sirt Distribution Curvs.BS
I
I
Inm-N   /“t9”F   JUiJn*?   *TTC
JT
CJH PWtfA Aimrb-V
Sup
ervisio,,^^!^
'M
rue rulJtt '^i'-
,
Laboratory c l  »e
r >n
Project
(Client
N»le Irrigation and Drainage Project(Upp
er Beles Storage Dam”
5lnr  -r^—
an
S»i
(j()|)
Addis Geosyslems Pic 
Sum. No : 3
'* ’*h
Loci non : Upper Beles 
Sam Type : Disturbed
Blf-No. UBD-5
Test Type ; Dry Sieve
Depth(m). 9.00-10.00
Date: 13/12/10
Total nan q] sample 1917.00
J/flY
UpfJBWglWJ*
Mai  j  of Sieve (g)
If MJ  SffH *
Rrr
Man of
KcZ. sod fe)
Percentage
Retained
Cmemtafim % Retained
Pertentaj^t
Passing
7100
1800.00
1800 00
0.00
0.00
o.oo
50.00
1205.50
1586.00
182.50
100 00
9 52
9.52
37.50
1087.80
1880.50
792.50
.
90 48
41.54
50.86
25.00
.
49 14
1191.20
1915JO
724.00
37.77
88.63
.
11.37
19.00
718~50
875.00
156.50
8 16
96.79
3.21
12.50
586.10
657.60
51.50
2.69
99.48
0 52
950
598.40
606 90
8.50
0.44
99.92
.
0.08
4.75
578.10
578.10
0.00
0.00
99.92
0 08
2,36
555.00
555.50
0.50
0.03
99.95
0.05
2.00
551.10
552.10
1.00
0.05
too.oo
0.00
118
558.90
558.90
0.00
0.00
100.00
0.00
060
516.70
516.70
0.00
0.00
100.00
0.00
0.30
488.20
488.20
0.00
0.00
100.00
0.00
0.15
481.90
481.90
0.00
0.00
100.00
0.00
0.08
459.20
459.20
0.00
0.00
100.00
0.00
PAN
425.50
425.50
0.00
0.00
100.00
0.00
1917.00
Grain Stea Distribution Curve.BS
100.00
90 00
B0 00
70 00
60 00
50 00
40 00
MOO
20 00
10.00
0.00
Gravel
Chet kid b
f
TITI
Water Works Design and Supervision Enterprise Laboratory
Service
ie Project(Uppef Betas Storage Dam)
irrigation and Drainage Gecsystems Pic
y-*
Sam- No : SPT-1
Sam Type : Disturbed
Test Type : VTct Sieve + Hydrometer
Date; 12/12/10
Total matt of Jamplt Before mvA . £
Talmas: of sample Aftrr twh
12222
10350
Most of
R/r. soil
Ptrmtop
Cjtuniainf
Pfrrrftfdgt
Rj/aifud % Rffantfd
0.00                 0.00
0.00                 0.00
0.00                    0.00
29.46                  29.46
13.91                 43.36
6.55                 49.91
11 86                 6177
9.41                 71.18 532                  7650 0.00                  76.501 3,27                 79.7? 2.45                 82.23
1.23                8346 0.82                 84.27 0.41                 84,68
1532                100.00
Pasmfc
1800.00
0.00
0.00
100.00
100.00
5i6.1O
1087.80
T227.20_
J35 50
594.10
0.00
36.00
17.00
8.00
1450
1150
6.50
0.00
100.00
70,54
56.64
612.90
589.60
533.00 539.50
551.10 551.10
538.90 542.90
516.70 519.70
50.09
38.23
28.82
2350
2350
488.20 489 70
481.90 482.90
459,20 459.70
425.50 444.22
4.00
3.00
150
1.00
0.50
18.72
2023
17,77
16.54
15.73
15.32
0.00
2.84
Trtprutan
Tut Ttmpfrahaf, drg.
Com did
Hydrone:rr
Cocffiatxt
20
Grau
PrnrnZig'
nycn*cttr
^210000^ 20.0
I • torr
----------—-
Rjadnif 1
21.0000
0.01293
0.0328
CofobtJted
8.97
 27.0000
20.0^
20.0000
0.01293
0.0208
20.0
20.0
20.0
17.0000
15,0000
14.0000
1350
13.80
0,01293
0.01293
0.0125
0.0088
21.0
20,0
10.5000
8.5000
14,00
14.60
14.90
0.01293
0.01270
00062
0.0031
0.0015
*>4 *
s 
V-t
1              p*** *rnon   rvFt Jims ♦TTC JTG.
vnntTt ftirHH
Wafer w
*
_____
5up’rvi,ion\7^8^
Nite Irrigation and Drainage Project(Up
per Beles Storage Dam)
--
Addis Geosystems Pic 
Sam No : SPT 1
-        --
'Oh
Upper Betes
Sam Type : Disturbed
UBD-5
Test Type : Combine Graph
100 145
Date: 12/12/10
luted by/ater Works Design and Supervision
Enterprise Laboratory Service
^nd Dra‘^e tef ns P>c
Pro$ect(Dpper Betos Storage Dam)
Sam. No: SPT-2
Sam. Type : Disturbed
Test  Type  :  Wet  Sieve  ♦  Hydrometer Dare: 15/12/10
sample 0<fort wash, g 'sample . Aptrr wash ,
Percentage
% Rflaintd
598.40
180000
1087 80
191.20
718.50
601.60
609.40
578.10
5)300
55110
518 90
596.60 540    50
Retained 000
0.00
0.00
0.00
0.00
18.90
13.41 22.56
9.15\
516.70
488.20
481.90
459.20
425.50
489.70 482.90 459.70 446 50
2.75
Total Mass of. Tola/
Mass of
fat. soil
0.00
0 00
0.00
0.00
0.00
15.50
11.00
18.50
7.50
0.00 3.50 2.00 1.50 1.00
0.50 21.00
Corrected Hydrometer
Reading
22 0000
20.0000
17,0000
150000 12.0000 11.5000
9.0000
0.00 0.00 0.00 < 0.00
0.00
18.90
32,32 5488
64.02  \
551.10
542.40
518.70
0.00
4.27
2.44
1.83
122
64   02
68.29
70.73
7256
73.78
0.61
74.39
25.61
10000
Test Temperature, deg.c
Aaual [ TtHfirutHTY
------------
_kadin;
Effective
Depth
(4*)
Cotffuwti K
82.00 61,00
Perrtntage
Passing
100.00 100.00 10000
100.00 10000
81.10 67.68 45.12 \ 35.98 35.98 3171
29,27 27.44 2622 2561
000
22
Grau
Ptnrxfcgt
Fhttr
mm       Candied
20.0
12.70
13.00
13.50
13.801
0.01325
0.01)25
0.01325
001325^
0.0)34
0.0214
0.0126
0.0090
14,30
14.40
0.01)2
18.92
17.20
14.62
12.90
10.32
22.0
20 0
14.80
f t* .?•
i; *• V
< e\V
A
SuXHOW nrl w™ ♦T
Water Works n t Supervision
Project:
Client: Locidon BH-No. Depth m):
Ndekrig^wnand Drainage Project(Upper Beta Adds Geosystems Pte
s Storage Dam) S‘ torage Dam\
Sam. No : SPT-2
'
1
i
Upper Betas
Sam. Type : Disturbed
UBD-5
Test Type : Combine Graph
%
J
2.90-3 35
Date: 15/12/10
I
!
I
‘1
1'■
»         TtJifd by:__ Chtdud bj:A.^ *TTTC
< ****4
Water Works Design and
Supervision Enterprise Central
Laboratory Service
Soil & Material Tasting Section '
^3i
##^^6%1M}1 45 01
P O Box 2561
Addis Ababa
It 251- ne-61 53 71(61 06 96
Ethiopia
tie irrigation and Drainage Project(Upper Belea Storage Dam)
W0'
O"*
Addts Geosystems Pic Upper Beles
LOCHiOH
BH no ■UBD-4
6 30-7.00
SaMm. No:
~*
e
Sample type Disturbed
Test    type    Atterberg    Limit Dale 16/12/2010
*ta ano computation sheet
LL
LL
LL
LL
No
035
048
199
189
N ofBkwi__________
34
28
22
16
lanplr • Tax
37.090
34 940
32.760
35 090
• Tare dry
33.320
31 560
29.640
31.480
Wofwatef
3.770
3 386
3 120
3 610
tm
14780
15.010
14.550
14.720
rtf. ;1 dry «*
18 540
16356
15.096'
16 760
Mtf OCfllfrtt %
20 334
20426
20 676
21 539
Type of test
PL
PL
Caneiner No
VX
61
Mdirnpto* Tare wet
29 130
28 830
W al lample • Tate dry
27410
27110
MoTwuer
“ i.tio
1.720
Tro
16430
16 350
*c# dry ioN
10930
10 760
fcMrcorteet*
15 737
15 985
15 86
Flow curve
22 000
/FB9
♦TTTC
Jtttf 16MT Mld-Ti /
Iiaia4
.. ..
-■ ■>»«
iR55 16/61 4501
Project: Client Location BH No
Te ‘ 251' <1* 6153 71/61 08 98
Fax .251 -116 ~S
e-mail W * d • NUelmgeOonandOfW
Addis Geosystems Pic
Water Works Design and Supervision Enterprise Central
Laboratory Service
Soil & Material Testing Section
P.O Bom          2561
**»’ W>abo
Ethiopia
Upper Betas UBD-4
Depth (m): 9.00-9.50
LlQUIO ANO PUkSTIC LIMn
DETERMINATONS
DATA AND COMPUTATION SHEET
Project(Upper Betas Storage Dam)
Sam. No J 4
Sample type . Disturbed Test  type  Atterberg  Limit Date . 28/12/2010
Type of test
LI
LL
LL
Conteine* No.
B-17
M14
B-13
No ofBtowa
30
25
18
IM of aampte ♦ Tire wet
32.020
32650
33.100
IM o' umpte 4 Tare 07
26.000
26.270
26.300
Wl of watet
6 020
6.380
6.800
Tare
16 96d
16930
16 570
Mof dry tod
9.046
9.340
9.730
Water content*
66 593
68 308
69.867
Type of test
PL
PL
ConteteerNo
F
11
IM of aampte ♦ Tire wet
27.870
27.700
Wl o# sample * Tare dry
25 570
25.200
Wtof water
2.300
2.500
Tare
17.140
17.000
Wt.Of dry toil
8.43C
8 200
Watr content X
27.284
30.488
28 89
Flow curve
T
i
4
<
Result
i    L_    67.97% PL_       28.89% p.l 39 08%
<
Tested By *
Checked By*TTTC
fL.Ct-iab«
Water Works Design and
Supervision Enterprise Central
Laboratory Service
>(<
^>1
55 1 8/81 45 01 251-116-61 53 71/61 08 SB
**
P.O Box 2561
Addis Ababa
Ethiopia
X imgauon and Oramage Project! Upper Beies Storage Dam)
pflA'1
f
Cje <
LuG3iXJn
gH Mo ‘
Depth (ml
Addrs Geosy s lems Pic Upper Belas
USD 4
!3.00-14-00
Sim. No;
Carrin.!* turus ■ rile
Sample type: Disturbed Test type Atterberg Limit Date 16/12/2010
dETpR'/|^
^O^PUSHCUMrT
T1OMS
ANO COMPUTATION SHEET
hr ryf ttit
—- -------------
LL
LL
LL
LL
177
026
123
097
qq ffl B^oWI
36
30
22
18
Vdlirf simple ■* Fur# wst
29 910
30.46Q
29.410
30610
W-cfump^ * Ifr® dry
23.040
23.890
23.150
24.020
W-ot*«1er
6 370
6.570
6.260
6 790
Tira
13.170
14 840
14.650
14 840
w»{if dry foil
9.870
9.050
6 500
9 180
YWtf artwl %
69 605
72.597
>3.647“
73 965 ]
FyptOlliat
PL
PL
65
25
'M of itrTcie <- Tara wet
28.620
28.56C
'N ol Mmpie * Tare dry
25.610
25.400
W of wakf
3010
3 160
Tin
16.260
16.240
<0* Jry Wil
9350
Idirarcytini %
9.160
32.193
34 498
33 35
Flow curvt
Result
L.L   72   60% P.L   33   35% P.l 39 25%1
i
|
i
pb, Ml jiw> ♦tttc
ttJH RtMt 1-04-+A
47U7A-+
AM*
Tel. 251 -116 - 18 55 16/81
Fax 251-116-61 53 71/61 06 96 e-mail w.w.d-a.efjethionetat
Water Works Design and Supervision Enterprise Central
Laboratory Service
-oeo, 2ssi
Addis    Ababa
Ethiopia
$
"Lt
Projecl: Nite Irrigation and Drainage Project Upper Bales Storage D
Addrs Geosystems Pic
Sam. No:             4
Location
Upper Beies
Sample type Disturbed
»
I
••
j
UBD-4
BH No :
Test type Atterberg Limit
Depth (m) 1.00 1.45
Date 04/01/2011
LIQUID ANO PLASTIC LIMIT
*
I
DETERMINATIONS
1
DATA AND COMPUTATION SHEET
Typed test
IL
LL
LL
LL
Container No
17S
G16
13-1
7
Nc o< Btowi
34
28
22
16
Wld sampte ♦ Tam wet
36.500
35970
35 680
39220
Wl of sample ♦ Tare dry
29 680
29 520
29.100
31.310
A*, olwaitr
6820
6.450
6 580
7 910
Tare
15.920
16 910
16 570
16.460
wtof d^ *od
13.760
12 610
12.530
14 850
Waler content %
49.564
51.150
52 514
53.266
Tywonesi
PL
PL
Container No
007
8
W of sample ♦ Tam wet
32260
25290
of sample ♦ Tam dry
28780
21.820
Wt o< water
3.480
3.470
Tam
16.620
10.030
wtof d-y tod
12.160
11.790
Water content*
28.618
29.432
2903
Flow curve
Result
L  L  51  42% P.L       2903% PI 22.39%
«
J
1W* *7* * inn**
^^^1fi"T55
i6«i4 oi
5
fL    251    -116    -e-53    71/61   °fl    98 ..mall w.wd.«.e®ethlonetet_
Water Works Design and Supervision Enterprise Central
Laboratory Service
So/f 4 Material Testirig .Section
P O Box 2561
Addis Ababa
Ethiopia
Nife'lrrigation and Drainage Project (Upper Betes Storage Dam)
Adds Geosystems Pic
C '”2L Upper Bales
L0C* II URBDU-U4-4BD-4
No
10.00-10 45
LlCUO ANO PL*ST1C LIMrr
rj TERMINAWNS
>T * AMD COMPUTATION SHEET
Sam. No:               4
Sample type Disturbed Test type : Atterberg Limit Date 04/01/2011
Ffpe of test
LL
LL
LL
LL
■■.veor No
045
F22
085
——------------------------- JSO C^QlOWS
66
34
28
22
16
Wto-tarnple ♦ Tin wet
35 630
37.040
35 680
34 130
^ya»npie • Tao dty
27 290
28 200
27 380
26 240
few**
8 340
8 840
8 300
7 890
16 290
16 710
16 730
16 280
mt^diy soil
11 ooo
11.490
10 650
9 960
war comrw %
75 818
76 936
77 934
79217
[Typt cf test
PL
PL
bwie'No
D9
35’
W o' unpie ♦ I art wet
28 370
30.450
>M of sample • Tare dry
25 580
26 960
W 2f water
2.790
Jai ‘
3 490
16.800
16 180
p*dr,
8 780
10.780
&«*'Warn %
51.777
32 375
32 08
Flwcurvs
Result
LL   77   28% P  L  32.08% PI 45 20%
10
100• I
nay rtFT X.W? ♦tttc
JttJH W 4flA.fi
Tel 251 -116-18 55 16/01 4501 Fax 251-116-61 53 71/61 08 98 e-mail ww±e.e®ettiionet.M
Water Works Design and Supervision Enterprise Central
4 Laboratory Service
P.O.Box 2561
Addis Ababa
Ethiopia
H* *■--------- TrtOffiinage ProjecKUpper Beles Storage Dam)
Project
N*e im—gaW0 and
Client Addis Geosystems Pic
Location: Upper Beles
BH. No U0D-4
Deptti(m): 11.90-12.35
LiomoAND plastic limit
DETERMINATIONS
DATA AKO COMPUTATION SHEET
SsmNo:             4
Sample type Disturbed Test type Attertoerg Limit Date 04/01,2011
Type of lest
Pl
Pl
ContmrNo
008
B-3
Wlo< sample ♦ Tare wet
30 190
31450
Mo’ umpN ♦ 7 we dry
26.460
27.610
Wl.of waler
3 730
3 840
Tire
16.190
17.540
M. of dry wl
10.270
10 070
Wteer content %
36 319
38.133
37.25
R
ow curve
77 000
*
c  76  000
Result
o   75000
1 L 74 25%
|      74000
P L 37 23%
PI 37 02%—
o 73.000
72.000
Tested By 
f| *
J® - J v*<
’
Checked By JfaT
Approved fly
• - * ■
i.mr* *tttc (»’ ''JfL*’ 'M't+4
251-116'1&55 16/61 4501 Jt 251 -116 -61 53 7W1 08 *
f t w w <*•« *©*thiontt rt
Water Works Design and , Supervision Enterprise Central
Laboratory Service
POBox 2561
Addis Ababa
Ethiopia
*   Xtion   and   Drainage   ProjectfUpper   Belen   Storage   Dam)
CD»nt
Loca®011
Nite iry 
A<Jtjs Geosystems Pic Upper Seles
Sam. Nq .
?
UBO-5
Sample type: Distorted Test type Atterberg Umil Date 08/01/2011
^7 0°
'cUK, AND FUSTIC LlMfT
flTAAND COMPUTATION SHtET
, Z7 WCt
ftyp”——.—--------------
LL
LL
LL
LI
56
004
005
012
nfSkwE
36
28
22
16
^nlun^e + Tam *<>
33.150
35.470
35.480
34.440
^tofumpu ♦ Tare dry
29.500
31.350
31 210
30.290
wtc/wtor
3 650
4.120
4 270
4.150
Till
16 220
16.910
16.570
15 460
koi Wy so«
13.280
14.440
14.640
13.83(5”
kne* ton tert %
27 465
28 532
29.167
30.00A
test
PL
PL
^trnwer So
052—
2
w^senpa • Tare wet
28 760
25.190
;«lol sample * Tats ary
26 800
22 800
St tf water
1 960
2 390
■re
16 500
Mdryaoti
10 030
10 3oo
12 77D
content %
19.029
18716
18 07
Fkow curva
12D00
Result
LL       2572% PL      18.87% PI 9.55%
fiurmbarof Blow*u M-nr*; *TTTC
Water Work* Design and
Supervision Enterprise Centra
Laboratory Servi
ce
/Soil 8.
P.O Box 2561
Section
” »,.<«■ S'»”»’««
Addis Ababa Ethiopia
Project: Client; Location BH No
e-"»«
W    W    d    6iS^Xge   Projectiupper   Betes   Storage   Dam) Sam. No-.            4
Nite Imgatton and Dratnag
Addis Geosystems Pic Md is Geosy stems c Upper Beles
UBD-5
Depth (m): 2.90-3 35
□quid ano pus'ncLwrr dcterminations
data ano computation sheet
Sample type Disturbed
Test type Atterberg Limit Date 04/01/2051
TypeoftaSt
IX
IX
LL
LL
Container No
9
19'
p
H
Mo of Blows
34
28
22
16
W of sample * Tare wet
38.630
34 540
38.300
34.730
VM of samp* 4 Tare dry
30 120
i7.690
29 740
27 610
Wl of waler
8.510
6 850
8 560
7.120
Tire
16.560
16.740
16 380
16 540
w* of dry so*
13.560
10950
13 360
11.070
Waler content %
62 758
62 557
54.072
64 318
Type of test
PL
Pt
ContewerNo
F15
16B
W.of sample 4 Tare wet
27 990
29.450
w of sample 4- Tero dry
" £5.100
26.310
V/ of water
2 890
3.140
Tart
16.200
16 360
< of dry uM
8900
9.950
Water content %
32.472
31 5f>8
32.01
Flow curve
i i
i
65.000
64 000
63 000
62 000
Result
L   L   63.33% P  L  32  01% p» 31 32%
I
i
I
J
Tested By _
Checked By^
Approved By
1♦ TTC CT*+
I** flfit+4 w' *
-
Water Works Design and Supervision Enterprise
Laboratory Service
Fax  251  •  116  -  61  53  71/61  00  98 e-mail w w d s e@ethionel.et
Test Method: Dlsotvlng
P.O Box 2561
Addis Ababa
Ethiopia
Location .*
and Extracting Instrumental
w><1'25)_____
F<KCL( 1:25)_____________ ECirns/cm) (1:2.5)_________ SfrNa(meq/100gm of soil) Inch K(meq/100 gm of soil)) EdiCa(meq/100 gm of soil) EjthMgimeq/100 gm of soil)
S^a/Ctoni (meq/iQOflm of soil)
CECirneq/100 gm of soil) jrcanic Carbon(%)_________ Ndogen (%)______________ Rafale P(mg PjO^kg soil)
AallableK(mg K?O/kg soil)Appendix 4.b: Laboratory Test Results - RockLaboratory Test Results - Rock (Borehole)CONSTRUCTION Of SIGN SHAW CO
lAtoworrnsittsuiT
Project -Nile Irrigation And Drainage Project ( Upper Bclr, Client :• Addin Gant y ate m PLC
Location :- Upper Boles
Object :• Tow Rock Sample
-
r “«e Dam )
BH
No
Depth In
( ro»
Nttanil
Moblure
Contest
(M
Water AWorpUon
(%>
Dry DanMty I
Egan'
UCS
( KNAm' >
Modulus Of
Elasticity
< KNAn? )
Voraaity
nJ
54729
13GB2T7
1
I
LfPii > - 5 |uBD-8
1 |4 4^15 M
1
|       12.15
2250
-
1
1- M»
Approved by
Tested       by       Amsalu       Mulugeta
Date
*02/01/2011
Checked      by     Abate     Legetse
Date
’01/01/2011
HEASE MAKE SOW THAT THIS tS THE COEWC1 BSW MEOW UStForm H*
OF/CDSCo/139
Iwue N*               fogtH*
1 Page 1 of 1
W.O.N” = 05412
Dale -01/10/1
s
(lien*
Nt le lrrie«lio”  *
Addis Geo» «ro
Upper B*'cS
Rock samples
Drainage Project/Upper Beles storagi P.L.C
Dry
Density
S’
T’
i
Sample
N"
LHD1
UBD1
Depth
(M)
Water Absorption
(*)
Moisture
Content
(%)
porosity
n
%
DCS
KN/m*
Secant modulus of
elasticity
kW
i        LBDI
♦        IBD1
i        IBD1
i        UBD2
7        UBD2
fl        UBD2
fl        UBD7
10       l’BD7
( 11       VBD7
“ 1.65-2.25 13.06-13.38 23.77-24.03 26.10-26.30 33.00-33.20
6 51-6.75
13 16-13.41
2265-22.90
6 65 6.94
13.10-13.34 17 44-17.65
2.28
11.38
40.77
-
-
11.52
9 48
8.44
903
8.43
5.71
2532
2200
1296
2020
2307
1972
2194
2250
2159
2378
2291
0.98
5.74
22.33
-
-
1.2*
6.28
3.93
7.75
4 80
3.87
1.4
2J4
12.4
-
084
238
2.1
345
289
1.58
36572
29787
-
3539
45294
48001
25478
20524
20495
15961
20495
2540157
1567737
-
-
-
-
•
•
-
-
Zln*hu E»k«tu
ilMorio
Approved by z-Girma Mekonnen
£•"'7 -Ab„.
** ’• iviono
Date
15/18/10
>F Sl’*E 1MM THIS IS TmE CORPFCTI55U6 B€ O*£<J>f
rAppendix 4.b-2: Laboratory Test Results - r
I J
)
JlaB 1I& Drainafle
B'• ABC1S QEQSY§TEM§_EL£
Yoar Ref.No. AGS> 10352 ON: 244M/10
*l[fOF: flock Sample
U T|O>: i nner Belles storage Dam quarry site
' *1 i;rQ»^^rn' Drv D«n»tV* Water Absorption, Porosity &■ Slak Durability S,,rr0 T.> ADOIS GEOSYSTEMS PLC
DaleON^^OnO^
;
Sample
No
Dry Density
g/Cni3
Water
Absorption
(%)
Porosity
(%)
SZaAr
Durability
(%)
UPSQ1 (BASALT)
2.962
0.214
0.63
99.67
UPSQ2 (TUFF)
2.155
9.00
17.90
99.34
.      ' «4ft
hanged.
»o«, Ar»re».t~ A L L L
k^uktwcoou material^
A.ph»h». C.aw.ta, Water reinforcement .uet b.rv
P.O.Boi 41726
Fix:- 231-1-514231Revision
0
TRANSPORT CONSTRUCTION DESIGN SHARE COMPANY
Material Testing Result For Aggregate
LAB. NO : 335 A 338 0003
PROJECT    1   NW    InWtai    and    Prato—    liatir    Bataa    Btor-^    p^. submitted by : Addis Geosystams PLC
SAMPLE OF : Rock
date sampled : —■—■■« STATION : Quarry Blta (Burfaca Pxaoaura) TEST REQUESTED : MBACV TFV
a
reported to : Addis Geosystems PLC
Sample Ho
Station
UPSQI (Basalt)
UPSQ2(TUFF
1. Soundness loss by Sodium Sulf ate (AABHTO T-104)
1%
___ *           I
2. A   r<i9«te Crushing Value (BS 812 part 110)
BV
17%
3. Tan percent Fine value bl wet Conditio* (BS 812 part 11O)                            230KN
BOKM    J■^.vncany Name:
Document No/
TRANSPORT construction design SHARE COMPANY
Material Testing Result
<
I
OPrTCDJ093 ■
I
1i
Page No.:
Irrigation and Drainage (upper Beles storage dam)
^^edby^odis geosystems±lc
mPLE OF: Rock
Page 1 of 1 Your Ref.AGS/10/352
No:
S>;Tl01
s- Quarry Site (Surface Eufflire)
:
\TE SAMPLE D:;        - - - —
P ^ct REQUESTED: Potential Alkali-Silica Reactivity
^PORTED TO: ADPLS_GECgYSTEMg PLC
I. Sample No:- UPSQ 1 (Basalt)
Reduction   in   Alkalinity,   Rc    =   295   mmol/lit
Date ON: 29/09/10
---—■
Dissolved Silica, Sc
II. Sample No:- UPSQ 2 (TUFF) Reduction in Alkalinity R  -
= 133.2 mmol/lit
c
Dissolved Silica Sc
532.5 mmol/lit 99.9 mmol/lit
^•^Rqjorted by;
becked
Hal
n □>
°T o|
t
TnE MajOR SERCISES RENDERED BY
L Appro*
dhrfciofl
CTS
eMC*ftcCr*Bf properties of ybtIssj C^trhAlpn mat __ __  w iqU» *lXTrE>te% Asphalts, Cements, Water rdnlarcenM(Sih C 289
-L__
-T
,
.A matter espo««‘®" mor< *hon 01 per ctM,n 0 ytQr
* eK(.nt«ntolni"» '-38
coul*« , . mnflor oponiion less thon 0.1 pcrcant mo yfOr
AQ wrdt'     ’0,nt       Ch*eh     mortar     eipo«»ion       dole     ore       n°’     ovoilobla     but
iaaf»««,fl
which 'n’'V h morlor eiponsion do’° °rt no1 ooilobte but
A og t?o»«’ Co/to b« Innocuous by pettogroo Me eiomiea it0R
io be dclc»i"Ou» by pctrogrophic •iOminelian.
-hici arc '"* °
c
B ouRdo»y "
nt ®tT
i
•„ innocuous ord dticiariput oggr«q
Q tt.
I Aggregates 
Considered . Potentially " De’.etericjs
11
Aggregates Considered Innocuous
75 100
Quantity S_ - Dissolved Silica (millimoles per l'lre)
c
— __ ----------------------- _--------- ----
lnor>o.tt. w b..i.Geological Survey of Ethiopia Geosciences Laboratory Center
Result Form
- Chemical: Lab Section: - Silicate
Waler
-■            - J""®
Hydrocarbon j " j
rA:
;< s<Tfn
m -Mineralogical: Lab section;-Mineralogy p j Physical .............................................................
;
lk nt
.
/Originnto Name: - A<14isjG^iSic!n±LC [Fitsuni_G^hunl
r
Category : - Survey [!
Gov. |
2 O.
jj-jJc n*'"e:
14 324/1OPVT Area Ref-:-
I .No of Samples: -J Sample No. 13JSQJ.
gpmple Typcj-RSSK- I" ’
1
*
14324?] 0
-fyp« of Analysis: ____________«_:-Petrography Preparation required: - Thin section Date Submitted: -_Z5/Q?£?PJO plland specimen Description: Black in color and very fine .grained in texture
jl) Mineral composition
Mineral
1 Modal (%)
Texture
Plagioclase
45
Lath
Pyroxene
30
1 Anhedral
Olivine
12
Eu hedral
Opaque(Ic-oxide)
10
Eu hedral -Anhedral
Volcanic glass
3
-
111) lextural Descriptions / Notes Porphyrilhic texture
(mnind^TM.ssjs mainly composed of lath mlGLOlitfiic plagioclase, pyroxene, olivine and opaque
miSr'l- Pl^enocryst5
-Q olivine and pyroxene arg_S£en over the microlithic ground mass Lath
f
chai«£ P-laK|OClasc show? parallel orientation. Volcanic glass is devitrificd to. .fibrous I' > Rock Name: -.PorphYrithic Olivine Basalt
Checked bv
Date Completed 07/09/2010
' ’ WtclulGte '
:A
?
I
opnen c.
CL G/KHI3TOS
"Vk.Z WurRfcii ----------- -----
<- ■'
Beige ! of 2Geological Survey of Ethiopia Geosciences Laboratory Center
Result Form
CaieTtam:- Chemical: Lab Section: -Silicate
Gold & Base metal -
Hydrocarbon ‘
15
a«Dtc«<s»n':-s,,nT> C—1 G“'’' | I' P"’     | ; |
file name: - 143J«£r Area RefNo of Samples: -2 Sample No.
Sample Typc:-R9ds_ L«b |Vo:'
Type Anafrris^cwraphv Preparation required: - Run section Date Submitted; - ^lt
I) Hand specimen Description: Rcddj^royaLincplQlJjnc grained andwejLhcrfidjM^u^ II) Mineral composition
i
X
t
Mineral
Modal (%)
Texture
Rock fragment
55
-
Volcanic glass
30
-
/
if     • 
>
Quartz
10
Cryptocrystalline
OpaquefFe-oxide)
5
Anhcdral
I \
: /V//
Pyroxene
Trace
Anhcdral
\
r
\
>1) re«M1
Jasall and rhvnlrt     a££_suspended over glassy and cryptocrystalline
’TBS!' Some empty (unfilled) voids are_se$n in the section IV) Rock Name: Lithic Tuff
Described Ib/ABiksti
1< Worked qt< J 2 . Adtse Mekonncn
Checked hv
Dale Completed 07/09/2010
G/KNSli^
' aod fV»T»i.< phy
k
*Appendix 4.c: Laboratory Test Results - Water
1. ml X.Hr>*-’ *TTC M«Wt
Water Works Design and Supervision
Enterprise Laboratory Service
, iWH-r Ms.®®**'®'-
Fax 251 -116-61 53 71/61 08 96
e-inail w w d.se@cthionel et
_ -gDPHYSIO CHEMICAL AND BACTERIOLOGICAL WATER ANALYSIS RESULTS ^imiect: Addis Geo-Systems
-------- --------------------
5CURCE OF SA.MPLE----------------
-
-
WHO
LOCATION___________________
^^cnF COLLECTION
Ur
: ----------------------
12/2/2003
10/2/2003
------- -
1
TTrc^FCEIVtD
pATt
CLIENTS ID.NO.
.
UCAQiIWHiUif (aop)
15/10/2010
15/10/2010
Upper Belles Dam
UBD-7
Upper BeileS
DemUBD-2
maximum
allowable
Concentration
(mg/1)
i aq id NO
B12/2003
813/2003
—
I*rr/——----------------------------
_
Tiirhlditv INTU)
• n11i Solids 105’C (mgfl)
T Dksaotved Solid 105°C(mg/l)
5.0
_
6200
226 00
1000.0
[Electrical Conductivity (pS/cm)
118 00
348 00
6.88
7 36
6.5-8.5
r
[Ammonia (mg/l NHj)
247
1.97
Sodium (mg/l Na)
900
52 50
200.0
Polittium (mg/1 K)
5 70
4 30
Total Hardness (mg/1 Ca CO )
3
43 70
76 00
500.0
[Calcium (mg/1 Ca)
13.68
1900
200.0
Magnesium (mg/1 Mg)
228
684
150.0
Total Iron (mg/1 Fa)
1.95
0.74
0.3
Jtangarwse (mg/1 Mn)
0.1
Fluoride (mg/1 F)
0 72
0.91
1.5
Chloride (mg/1 Cl)
1.82
1.82
250.0
Nitrilo (mg/1 NO,)
008
002
Ntat» (mg/1 NOj|
1.87
0 69
*JI«llntty (mg/1 CaCOJ
45.0
62 70
174.80
.jTbonat* (mg/i co,)
Nil
Ni!
SWbonate (mg/t HCOJ
^Pwe (mg/1 SO )
4
•^H!Hlnurn (mgA Al)
The test result can t
.____>      .L
y)lpresented on the last column Th^wetersampie was collected and submitted to _guMabo>atory by the client.
76 49
21326
8.70
452
(mg/t po4)
400
0 30
0 32
Nil
^  5_(mq/l)
ro
Nil
0.013
o
0013
>e compared with
---------- J_________________ the WHO maximum a I Iowa b
le concentration
----------------------------
Approved by
• o
*: . /•ft
Date:
‘IFfirv.'
r                  Mnuty tfWattr and Eatrp
Efirtfn .Xii JryflrfftM jad Dn**^t PnfrrtAppendix 5
Picture s showing mobilization and drilling
Activities at upper Beles Dam site.Photo 1 &2: Transportation of rig parts and accessories to dam site by human laborPhoto  3  Inter-borehole  mobilization  by  local  labor Photo 4: Camp for drilling crewVr^rtyjl DtBxrjfit R/fMi
Miwtry of ITafrr jod Eotrjp
Efhiopu* N/>                  ad Dnrc^r PrwMW(
- dJ£*^
ANNEX F
DAM SITE SLAKE DURABILITY PHOTOGRAPHSFe/M Dt9ocm/h RfpoHn (f F.tbeofea, Mimrtrj of Wat er & Eoer^ Ffaefoo* Mt Irngotwv Dwy ProjectUpper Beles Dam Site Core Samples: Slake Soaking Test
^^slakc soaking test is a subjective test to observe the performance of samples of
^•k when placed in water for a set penod of time. By photographing the samples, it is f,X sible to observe w hether there is any reaction of the material to being soaked (for ^amplc swelling, disintegration, spalling or ’slaking’).
Samples of lithic tuff borehole core from the Upper Beles dam site ground investigation were immersed in fresh water for 78 hours and were reviewed and photographed periodically (approximately 4 to 8 hrs) on the following schedule.
Testing was completed al Addis Gcosyslcms Co. Ltd core store / offices:
Date and Time
Duration from start (hrs)
05/10/2010: 08:00 hrs
0
"05/10/2010: 14:00 hrs
6
05/10/2010: 18:00 hrs
10
05/10/2010: 22:00 hrs
14
06/10/2010: 06:00 hrs
22
06/10/2010: 16:00 hrs
32
07/10/2010: 14:00 hrs
54
08/10/2010: 14:00 hrs
Photographs are shown on the following pages for periods highlighted in bold
The samples tested are from boreholes L'BDOl and UBD02 on the left side abutment
and comprise slight to moderately weathered lithic / agglomerate tuff.
BHUBD01
BHUBD02
____
5.00m
17.70m
6.75m
20 00m
7.20m
21.75m
—___
9.05m
he photographs show that after about there is some spalling within the first lOhrs of soaking, but no significant change from then until about 22 hrs after testing. From
v erbal Communication with Addis Geosystems Co Ltd, no significant disinlegralion *s reported after 78 hours, but photos and measurement are not availableUpper Boles Dam Site Core Samples.
Slake Soaking Test: Before Soaking: 4/10/2010, l2:00hrs
(wore test started at 08:00 ltrs on 05/10S2010)Upper Beles Dam Site Core Samples.
Slake Soaking Test: Soaked in water-05/l0/2010: 6PMlipper Beles Dam Site Core Samples.
Slake Soaking Test: Soaked in w ier-05/10/201G: 10PM
fl
UBD2Upper Beles Dam Site Core Samples.
Slake Soaking Test: Soaked in water-06/10/2010: 6AMM I"**"* nJ Dim* p^
dam site
ANNEX G
GEOPHYSICAL SURVEY FINAL REPORT JANUARY 2011M** 
Krp-rv. tf
Mtflh ^V’arrr f ^»np
f .’♦mX/w .V<r /•nfbt*** <«•/Pn««<frt
GEOPHYSICAL survey at upper beles dam site
Final Repo ’ January 2011
Contents
I     INTRODUCTION........................................................................................................................... 2
/J ftAOCCMXJNO ..................................................................................................................................................................................................
12          O^ECTl^OfT^aonmKALiUKVm......................................................................................................................................................... 2
fj            LOCATION A^D Acaisa^ny............................................................................................................................................................. 3
1 GEOPHYSICAL SURVEY................................................................................................................ 5
Zl GENERAL................................................................................................................................... 5
2J      Survey Latout and Summary Syatktig.................................................................................................. $
22 lNSTRUMENTATX)N ANO FlElD PROOTXJRE.......................................................................................................................................  5
2.4   EMta Processing and Presentation.......................................................................................... 7
J. RESULTS AND INTERPRETATION.............................................................................................. 8
3.1        Une-I........................................................................................................................................................... 3
32        Une-2......................................................................................................................................................... 10
JJ    Une-3......................................................................................................................................................... 12
*4     One-4........................................................................................................................................................... 13
4. CONCLUSIONS AND RECOMMENDATIONS........................................................................... 14
4.1        Dam SHE............................................................................................................................................................................................ 14
42 SwitWAY....................................................................................................................................................................................• ’ w r 15
1I.   Introduction
1.1 Background
The Upper Boles Dim Project is part of a larger planned irrigation
under the Ethiopian Nile Irrigation and Drainage Project, The m
proposed for the largest dam option consists of a dam crest of more th length on the Upper Beles River and a spillway about 280m southeast of th end of the dam axis.
This report describes the geophysical two dimensional (2D) Resistivn surveys conducted at the dam site along four lines for the purjsose of investigation. The first two lines are located in the dam axis area, where two lines are in the spillway area. The surveys were made at threi
periods between July 10. 2010 and September 26. 2010 because of accessibility of the site and the problem of crossing the river to the right s flooding and high water levels.
1.2         Objective of the geophysical surveys
The original plan was to measure two lines, one along the dam axis (H another across the dam axis in the central left side of the river over terrace (300m). Later on, due to the modification in preliminary dan spillway site was selected, and two additional lines were investigated, one another across the spillway axis.
The main purpose of the geophysical survey conducted at the site was
•    To determine the depth to bedrock;
•     To determine the thickness and degree of weathering of the bedr
•     To determine the existence of geological structures, i* ^aU fracture zonesThe depth to bedrock at the site of the spillway determines the cost of the
crvccure. which depends on the difficulty of excavation co the extent of blasting if shallow bedrock may be found.
j.J Location and 4cc«jlWffty
The   Upper   Beles   Dam   site   is   found   on   the   Upper   Beles   River,   about   15   km northwest of die town of Yismafa in Liben Woreda. Awi Zone of the Amhara
Regional State.
The sice can be reached from the Addis Ababa-Bahir Dar highway by branching to the north at the town of Durbete. Durbete is found at about 475 km from Addis Ababa. Thereafter, a good gravel surfaced road of about 30 km to the leads to the Yismala The foot path to the site from Yismala has a very steep descent, and is thus difficult. Therefore, another route had to be found
The preferred access is along the Tana Beles Project road to the outlet area. From the end of the road, access is on foot to the project site, either along the left side of the river or across a foot bridge and along the right side of the river. In both cases, the site can be reached after two to three hours walk over undulating rough terrain.
The location map of the project area is given in Figure I a.Figure la. l ocation Map of the Upper Belrs Dam Site.
42.   Geophysical Survey
2 J General
Geophysical surveys provide useful information in die planning and implementation phases of large construction projects, where the geological conditions of die foundation beneath the proposed structure should be investigated. In this regard, geophysical surveys provide indirect information about the subsurface condition to supplement the engineerIng geological investigations.
The geophysical method employed in the present study is the Two Dimensional (2D) Resistivity Imaging Survey, which is able to furnish subsurface information both in lateral and vertical direction. Different geologic materials show significantly different physical properties, the measured property in this case being the resistivity of the subsurface to electric current flow.
2.2  Survey Layout end Summery Statistics
Four profiles. Line I to 4. were laid out in the area and investigated by the 2D resistivity imaging method (figure lb). Line I is laid out along the dam axis, and is 1030m long, whereas Line 2, which is 300m long, lies across the dam axis in the central left side of the river. Line 3 is located along the spillway axis, whereas Line 4 is perpendicular co Line 3. The length of Line 3 and Line 4 are 150m and 250m, respectively. Line I and 2 are subdivided in to segment A and B to indicate rhe slight bend along their course.
Along the dam axis on Line-1, the river bed is about 45m wide, and lies between picket 670 and 715. No data was collected within this section as it is covered by water.
A   hand   held   eTrex   Garmin   GPS   receiver   was   used   to   measure   the   UTM coordinates of the start and end points of the geophysical profiles, which are given in Table  I  below,  ft  should  be  noted  that  the  Adin  dan  datum  was  used  in  the acquisition of the UTM coordinates.
5Table I. UTM coordinates of the 2D Resistivity profiles
Une Number
Start Coordinates
Easting
Northing
E^d Coordinates
Geophysics Une-1A
260480
1294085~
Geophysics Une-1B
260685
1293995
Geophysics Une-2A
260992
1293627
Geophysics Une-2B
261090
1293700
Geophysics Une-3
261525
1293415
Geophysics Une-4
261600
1293220
260685
261340
261090
261260
261675
261600
’293520
’293700
’293752
’293415
J _ J293470
2S0
ner?z«r that can
P to huOmA. at a maximum output voltage of 350 Volt
pieces of equipment used include:                                                                        Additaonal Cable sets (for current and potential circuit)
•    Stainless steel electrodes
•    Connectors and clips, and
•    Hammers
pr* «. h.d bu. on 8round lrom ran the end polnL The !Qml
” l0CMed other ,n P*1* we«em or southern end. was labeled as nation 0
nd point was labeled by the maximum length o< the profile. Stations were wooden pegs/piekets.
2.3  In rtru mentation and Field Procedure Th. PASI I4GL Eanh Rmiadwty Meter
«•*•> « PRW^d by ft. RAJI modc, deliver current up to SOOmA at a ma
lj
e 6ctf(
^png f
umberger electrode configuration was used, with smallest inter-
& O<
°f t*,e smallest inter-electrode spacing (n»)
:                              to n 6 were progressively used so as to increase the depth of
■nvewgation* th I
collected    in    6      'nter’electrode      sPac'n«    mainly    used    being    60m.    The    dan    » :uch a way that the distance between the potential electrodes 1$fixed at 10m. while Che current electrodes are increasingly spread out from a minimum of I Dm to 60m. At each station, measurements are made for all eiectrode spacings, and the whole set up is then moved co the next station. In this way, the process is repeated until the profile is covered completely.
2,4  Data Processing and Presentation
The 2D resistivity imaging survey data for each line is first edited to remove any
erroneous data which could have detrimental effect on the inversion process, The
edited data is input to the 2D resistivity inversion software, RES2DINV. which
automatically determines a two-dimensional (2D) true resistivity model of the
subsurface for the data obtained from the imaging survey along a particular profile.
The program divides the subsurface into a number of rectangular blocks, and tries to determine the resistivities of the rectangular blocks that will produce an apparent resistivity pseudosection that agrees with the actual measurements. The inversion method basically tries to reduce the difference between the calculated and measured apparent resistivity values by adjusting the resistivity of the model blocks in a number of iterations. A measure of this difference is given by the root-mean-squared (RMS) error,
The final output of the inversion provides three sets of sections, i.e. the measured apparent resistivity values, the calculated apparent resistivity response of the model and the true resistivity model itself. The true resistivity model section is further interpreted in terms of the local geology, and is presented in Figure 2 to 5 for the four profiles, respectively.J. Results and Interpretation
3.1 Line-/
The interpreted 2D resistivity section along Line-1 (Fig. 2) shows djjtinct responses generally marked by low and high resistivity.
On the right abutment, two distinct resistivity responses are found Th. r
’ nc T,r*t zon€
extending  between  station  0  and  400  dearly  indicate  that  a  two  hv.r
'*yer  struaur(! underlies  the  area.  The  top  part  characterized  by  low  resistivity  of  less  thlr  3o Ohm-m has a uniform thickness of 12-15m, which is attributed to highly weathered and/or fractured basalt The bottom part is characterized by relatively high resistivity response of 40 to 300 Ohm-m. which could be the response of fresh and massive rock.
The second zone extends between station 400 and the river bank at station 670. In this area, no clear layering is observed. But the zone is generally dominated by low resistivity response of less than 30 Ohm-m probably indicating highly weathered
and/or fractured formation or talus and terrace deposit depending on the topographic position. These low resistivity zones are more than 20m thick at places (e g. picket 460-500. picket 530-590).
In the area of station 600-610, a small body of relatively high resistivity (100-200 Ohm-m) is observed, which may be correlated to moderately to slightly weathered rock.
There is no data in the river bed extending between picket 670-7IS- But on section, this area appears as low resistivity which is simply an artifact intro the interpolation algorithm of the software.—
Elevation
Upper Bries Dan AxisRII
Mo  Or  J  resistivity  vith  topography Iteration 5 ANS error - 11.6
1*1*1
1m
139 B-
13BB-
137*
1368
135*
13**
133*
133*
1>1*J
To™ TTb™           ™^ri.T3 ™o"
Resistivity in ohn.n
Unit ElectreBe Spacing           - S.tR
Figure 2. 2D Resistivity Section along the dam axis, Line-l.The left abutment extending between picket 715 to 1030 u u is  nara
c
cteri u
resistivity response. Very low resistivity of less than 10 Ohm m
Vlrt’ble
area towards the end of the left abutment between picket °bSerVed «the
Indicating highly weathered and/or altered rocks with la a.
than 20m
The area between pickets 810 and 890 is underlain bv verv k.-k
Probsbly
of
X high resistiMty m
of more than 100 Ohm-m. The high resistivity response dearly co
7 or relates with the
outcropping tuff, which is probably slightly weathered to fresh.
Low resistivity values varying between 5 and 50 Ohm-m cover the down slope part of the left abutment between picket 810 and the left side of the river bank at about picket 720. The low resistivity response probably indicates the highly weathered nature of the underlying rocks which is indicated to have large depth extent in excess of 25m.
3.2   Une-2
Line-2 is situated in the central left part of the dam axis, and extends across the dam axis from downstream river bank to upstream river bank
The 2D resistivity section along the Line (Fig. 3) shows that the line is generally underlain by low resistivity layers of 5 to 50 Ohm-m. The low resistivity response probably indicates the highly weathered and/or fractured nature of the rocks.
The top part of the section covered with patches of very low resistivity oc PX the top 5 to 7m is probably attributed to highly weathered and/o
formations or clayey alluvium. Towards the northern end of the lin picket240. the lowest resistivities are observed having thickness of abou interpreted as clayey alluvium.Line 2111
Model resistivity with topography Elevation iteration 6 RHS error - 9.7
135 ftq
1345-
134ft-
1335
133ft-
132S-
132ft
1315
ubd6
(JBDl
240
3.l^™00                         111             3B.• 5ft.0                  100 Resistivity in ohn.n
"
Unit Llectrofte Spacing - 5.0ft n.
Figure 3. 2D Resistivity Section along Llne-2,
11The central part of the section. « intermediate depth, having relatively rno resistivity of 40-70 Ohm-m (e g between pickets 80-110 and picket |
composed of highly to moderately weathered rocks.
The  very  low  resistivities  observed  at  depth  below  25m  between  pickets probably Indicate saturation with groundwater.
50 to |4Q
3.3   Line-3
Line-3 is located In the spillway area with a direction perpendicular to the spy^,
axis.  The  2D  resistivity  section  along  the  Line  (Fig.  4)  shows  two  distinct  tones  o( contrasting resistivity responses.
The western end of the line, between picket 0 and 50, Is characterized by very high resistivity values of 30 to 300 Ohm-m probably attributed to the outcropping slightly fractured to fresh tuff bedrock.
Model rriKtiwltj Mitt
llvretiM i ■« error • It.5
Um-MH
i-----------
WtU
1M|.
im
UH
1H5
Figure 4. 2D Resistivity Section along Line-3.
In contrast, a Urge part of the line towards the east is underlain by low res’$ less than 20 Ohm-m, which indicates high degree of weathering and/or fra
. is more
the underlying rocks. The thickness of the highly weathered/fracturea than 30m as observed from the section.3.4  Line-4
Lme^l extendi along the spillway axis. The 2D resisuvfty section along the Line (ftg- 5)
s hows almost uniform subsurface stratification.
The top part along the whole section is characterized by low to very low resistivity response varying in the range of 3-20 Ohm-m. which may be correlated to highly weathered and probably altered formation having thickness varying between 10 to 15m.
The lower part of the section is composed of relatively high resistivity response in the range of 20 to 200 Ohm-m attributed to the bottom moderately weathered to fresh rock. It is observed that the depth to the top of the fresh rock increases southwards.
flwdel rriiitlvltf rirn
LSD?
i.m >.n v.w
‘
■■'Eistlvltgi In Blm.li
"J
- ------------- _______________________________ __________ Mt ffltcJrMKi tpartjHf • £, M ■.
Figure 5. 2D Resistivity Section along ldne-4.
134. Concknien* R‘KomfnCnd’Gon*
rrjtrml *h.ch correlates well with the resistivity result.
attributed to weathered and/or fractured rocks,
The rest of the dim axis is underlain by low to very low resistivity formation probably attributed to highly weathered and/or fractured rocks or loose material Such areas are found tn the right abutment within picket 400 to 670, and in the right abutment between picket 720 and 810. and 890 to 1030, The very low resistivity (< S Ohm-m) observed towards the left end of the dam axis, within picket 890 to 1030. may indicate alteration to day. and is more than 20m thick which should be verified by dnlmg or pitting Similarly, in other areas these highly weathered and/or altered layers have large thickness of more than 20 to 25m.
At  the  location  of  UBD4.  about  15m  thick  relatively  high  resistivity  material  a observed which correlates well with coarse grained sediments.lootion of UBO2 are charter emed by lbw ro medium high resisowe/ of M-50 Om- m down to about 13m depth. which may be correheed to coarse grimed tard mb gravel (up to 5m) and medium strong fresh lithic tuff up to Mm. Ac depth, low resistivity dominates contrary to the lithologic log showing slightly w«herod to fresh fithc tuff. It therefore appears that water saturation plays a major role m controlfcrg the resistivity structure »n the area.
In    general,    the    dam    axis    is    underlain    by    rocks    with    heterogeneous    future characterized by varied degree of weathering and/or fracturing.
4.2 Spllfwoy
The two lines measured in the spillway area depict varied nature of the subsurface
Line-]. extending in the E-W direction, shows that the eastern half of the line is
underlain by an extensive highly weathered and/or fractured rock or so*l with
thickness of more than 30m. whereas the western part of the line »s underlain
relatively fresh rock.
The results along Llne-4 in the direction of the spillway axis indicate that depth to bedrock is almost uniform throughout tho lino. Tho thickness of overburden is in the range of 10-15m. with thickness gently mcroasmg towards the southern end of the line. Correlation of the resistivity result with the borehole log of UBO7 is good But on line-3. the resistivity results do not match with that of the borehole log Low to
very  low  resistivities  of  less  than  10-20  Ohm-m  underlie  the  area  east  of  Picket  60
which does not correlate with the borehole log. The log Indicates up co 8m of loose material (chy. silt. highly weathered tuff), below which sitghdy weathered to fresh rocks are observed.
The variation in the interpreted depth to bedrock at the intersection of bnc-3 and Line-4, probably indicates the isotropk nature of resistivity in that reustmty vanes Wlth direction of measurement, and also that the subsurface configuration dong the two lines is also highly variable.Ftdrral Democratic Rcpubhc of Ethiopia. Minn tn of Water and Energy Ethiopian W/t Irrigation and Drainage Projecte* n«f<p
annex H.l
■pRIAl- PIT LOGS: DAM SITE AREAledtrai Dtmo-rufti
affirbtefna. Ministry of Wafer f*r Finefg-
Ethiopian Kite Irrigation and Drainage PrvjerfPinots
Project   No
HotelD
UBDP1
Sheet 1 of1
Botes Imgatoc Scheme
Co   s
BELES
,   ^       261155E
■      1293708N
Le ^ 1333 00mASLM
Date
□&O5/2010
Locate
tensions
Federal
Democr
atic    Republic
of
Ettwoe
Depth
Scale
1:25
Ministry o
f Waler
Resources
3 00m
Logged By
(■song
Depth*
urvet
TT
R**cTs
<J
m
ImASLM)
Loge
nd
2W          (M41,     bbkPa
:»     I rvx 21 7OP* :«                105M>>
hr.*
75kPa
»kPa
9flkPa
BSkPa
IDSiPb
******"(Ft►
ffalcrow —■!=
Project Name
Upper Bales Irrigation Scheme Location:     Betas
Project No
BELES
Coords 261315E-1293535N
Level. 140000m ASLM
1.40m
Client
Federal  Democratic  Repubbc  of  Ethiopia Ministry of Water Resources
Dimensions
Depth
2 00m
Samples ft In Situ leeting
Depth (m) | 1
Type] Results
(m ASLM)
1399 90
010-0 40
Stratum Descnptw TOPSOt- dartc grave*?sWyCLAY Gcr-ei fcOs*
Very gra^ly Mndy silty CLAY GrMl u grey co^o ngj* y boulder, cobWey veil, $,hy CLA Y Grrve i  w
angular (ColluMum)
5       lr
"* k
Stability:                    stable
Remarks:
Groundwater dry
FarmlandKalcrow £T.l
Project Name
Upper Betes Imgabon Scheme Location Bales
Project No
BELES
Coords    261267E    -    1293603N Level 137l00mASLM
Dm ens ions
1 50m
Depth
1
Client Federal Democratic Republic dl Ethopia
Ministry of Water Resources
2 00m
5'
Hole ID
UBDP3
Sheet 1 ol 1
Date 07/05/2010
Scale
1 25
TT
Logged By
Mnptai & In Situ T evil ng
Dtp*’ Typo Results
Dctxti Level
("I         (mASLMi
Stratum Description
Srrff dark tfqhlly yaveib uiry CLAY Gr»»el Is dark prey fine to mcdnxn
anptMr - Cceh/Murn)
0004 65
0
i
137015
rteafww'j
(Mw»och
rvco*«rvd
m   pirenh  grvy  silty  sandy  GRAVTl  Gm  is
greyish pr
e m«kjn to
Cosme eng
ulnr iResudu^ So*)
065-200 D
200
1369 00
I
nepi I'nmpiMa ■ 2.00 ir
io
I
Stability:
stable
Remarks.
Farmlard
Groundwater drytfalcrow 2X.1
Project Name
Upper Beles I
Project
No
rrigation Scheme
BELES
Location Bele
s
160m
Client
Federal    Democratic    Republic
of
Ethiopia
Depth
8
E
Ministry of Water Resources
2 00m
Samples & in Srtu Tnung
Depth
Depth (m) Typej Result
(rn)
Lewi
(m ASLM)
T
-x
r*X ££
•J - V
_-
__ D-* flrey grawtiy Mity ClAV (ColluvHjm)
S,r,,urT1 ^*criDl.or
” 
,0
M *
1
000-1 eo               D
1 80-2 00             D
1 80 1381.20
1381 00
Cor^M. * 2Q0 m
Stability
Remarks- Farmland
Groundwater dry
stabletfalcrow 2J1
Proied Name
ijppcr Betas imgalKJn Scheme
Project No
BElES
Cowcls 2«M9tE-t29396lN Level:         1347.00 m ASLM
Hole ID
UBDP5
Sheet 1 of 1
Cale
0&W2010
L OC3tX’n: 0eto*
150m
Cleat Federal Democratic Republic of Ethiopia
Ministry of Water Resources
Dimensions.
Depth          E
250m
Scala
125
Logged By
rr
. Type’ S»«*» tm)
Shirtum D*«njrtic<* Sbl" rUrt MtyCLAY fRrwr 'maro DepcMl
Drirh arfihny gra^. if silEto* CLAY Dfmnl h •arwytcJi dart rnffiturn .jiihmf *afr
naundwl 4 Rin** “'wane Di^e-Mv
StaOiiity
-Fb
^
- ar,
M.Sf'tdrru/ Dfar^rati. RspMc ofE/fdopia, Mi/riffr)  of Udler and Enrff)
1
Ethtopw* Nik Irrigation and I >nana$e ProjfitMir Imfimvn jutrf Dnn^ I’n-n;
ANNEX H. 2
TRut. prr photographs: dam sue areaFedtnd cruft. Pjfutbht oj Ethiopia, Mint/try of Water & Fifty Ethiopian Nik Irrigation and Drurna^ ProjectPlate I: Trial Pil L'BDPl SW side
Plate 2: Trial Pit UBDP1 E side and spoil—-—Hate 5: Trial Pit VBDP2 spoil
Plate 6: Trial Pit UBDP2 looking upslopc, left abutmentPlate 8: 1 rial Pit UBDP3 site area looking eastSlid IVIHJ.
3X15
wow
Si1as3s
isai uvi
f  H X3MxyFrrirru/ Drnr&rufi, Kspufa: Ethupa. Mtm/fn Effapan A7£ irrigation and Drm nap Prvprt, p |ncrod«c<i<>n
report presents Summery of laboratory test results of soil taken from Nile Irrigation and e  Project The lest results are Hydrometer, Alterberg l imit, Proctor. Linear Shrinkage,
p hie Hydrometer ar,d Moisture Content. The soil tests arc carried out following the appropriate pie preparation and testing procedure The following are the standard procedure followed to
arryout the analysis
1.1 Standard Procedures
iNa
T
1—“—
2
Type of Test
Hydrometer
Attcrberg Limit
Proctor Compaction
Standard
BS Test 7(A) & 7(D)
BS Test 2(B)
1 -
1 BS Test 13
L-------- J 4
Linear Shrinkage Limit
BS Test 5
5
6
7
1
Double Hydrometer
ASTMD422I
1
Moisture Content
BS Test 1(A)
Acid Extract Sulphate
BS 1377-3:1990 
(
Water Extract Sulphate
Turbidity Meter Method
9 Organic Carbon
10          pH
Walklay Black Method •
pH mlcterNile Irrigation and Drainage Project Summary of Test Results
16/06/2010
Parameter
Grain    Size    Analysis
Clay (%)
, Silt (%)
Sand (%)
1  Atlerberg Limit
Liquid Limit (%)
UBDP1
] (0.00-3 00m j
27.50
48.42
24.08
UBDP2
(0. IO-O.4Omj
32 0
31 37
UBDP2
(0.40-2.00m)
400
45.28
UBDP3
1 (O.OO-O.85m)
58.5
1         25.75
15.75
UBDP3
(0 85-2.00mJ
UBDP4 1 (0.00-1.80m)
48.0 42.47 953
UBDP4
d 80-2.00m)
•
-
njBDPs
(0.00-1.50m)
LBDP5
(1 50-2.50m)
r
T
36 63                          1442
——
-
•
43.50
43.16
13.34
46.0
33 56
20.44
73.88
I Plastic Limit (%)                           27.36
Plasticity Index (%)
Proctor
MDD(gm/cc)
0MC(%)
46.42
1 635
22.50
7.52
87.17
43.29
43.88
62.20
40.79
21.41
| 102.55 44 21 58.34
62.75
31.59
31.16
59 07
33.91
25.16
49.90
27.89
11.01
63.94
3445
29 49
53.60
29.23
24.37
-
•
-
•
•
■
1
Linear Shrinkage (•/.)
Double Hydrometer
! Permeability (cm/sec)
16.97
6.75
22 5
•                              750
•
14.54
12.04
I
—
J
ND
1.47 x IO4
ND
•
ND
ND
-
i
i
----------------------- L
1
____1
-
1
1
-
•
1
1
J
-4•r
1
Moisture Content (%)
12.11
1 1
37 28 24 26 1581
1
iL
22.73                        27 34
11
15.03 26.83
i
22.69
1L
i
_____ L
Jl
Note: - The remaining chemical tests will be reported as soon as the tests are completed.i—_
I
" r jjT.JH
jntHfr*
, r ***
iiX1*
T , Ha]cr^
,r '.Ln Pam Site
Ndc l^*tlon afld D
"  *P  Project
in      r
UBDP4. Layer A
, oOO-l-BC
Water Works Design and Supervision Enterprise Laboratory
Service
SoW & Material Testing Section
Sim No :
Sim. Type Disturbed Test Type: Hydrometer Dire : 26/05/10
Total miJH fff Tamp/f  g
t
50
Jiri*
{7/rA.'p^i,‘af^
Mats t)f
SifVf(£j
fajr
RrZ .rtity
Mau of K/A soil (g)
RtfaiNcd
Pfrfenhigt Pairing
iM J V  if?
. ,v r|r _
?
W.l
551.1
0.00
0.000
aoo
100.00
/J*
538.9
539.5
0.60
1.254
L?5
98 75 |
J0
0.6
516.7
518.3
1,58
3.303
4.56
95.44
\i ID
03
488.2
4894
1.23
2.572
7.13
92.87
0.15
481.9
482.4
0.47
0.983
811
91.89
7 .w
0.075
4592
4599
0.68
1.422
953 \
90.47
r
425J'
425.5
0.00
0,000
O.W
0.00
Hydrometer Arialyiia
Gw
rb a/ jw/
2.60
Tut Ttfrptralun. 4tg.t
?2
HOT
/
Rfi/ota?
Teftprubirr
fa
Cwfrr+W
Hyarwtter
R/jwtaij
Effufit*
Dtpri?
(a*j
CofficitKl
K
Groin
(jWStJ
Ptw.Lige
Finrr
CMtlnntd
* £?■
45.0000
22.0
390000
990
0.01353
00301
8250
5
42.5000
22.0
36.5000
10.30
0,01353
00194
77-21
15
395000
220
33 5000
10.80
0,01353
0.0115
70,87 (
JO
37.5000
22.0
31.5000
11.10
0 01353
0.0082
6tf.63
60
3 i.0000
220
290000
11,50
0,01353
0 0059
61.35
jfo
31.0000
22.5
25.5000
12,10
0.01337
0 0029
53.94
._ J wo
27.5000
20.0
20.5000
1290
0 01386
0 0013
Grain SL» Distribution Curv*,6Snun httc
Mzt- rtruw i/VA
Project: Nile Irrigation and Drainage Project
Client:         Hal crow
Location Dam Sire
T.Pil No UBDP4.1-aycr-A
Drpth(m) 0 00-1.80
Water Works Design and supervision Enterprise Laboratory
Service
Soil & Material Testing Section
Sam. No
Sam Type : Disturbed
Test  Type  1  lydromctcr(with Date : 26/05/10
OU!   sol’n)
i Totdl masi oj s umf it,
50
Sieve
Marr of
Ret, sod
Cumulate*
° 0 Retained
0.00
Percentage
Retained
0.000
V'rrentag Pan/Hf
1.18
0.6
0.3
doss of stn e Ret .soil(&)
551,1
539.5
0.61
_ J 0000^
1.275
1.33
0.75
2^*
~9872
No 100
2.781
1.568
4.06
0  33
200
run
0.15
0.075
481.9
459.2
425.5
518.0
4890
482.2
459.6
425.5
0.37
0 00
0.690
0.774
0.000
93.69
Hydrometer A
nalysis
0.00
ific Gravity o:
jw/
7
Flapped
Time
(min)
At Inal Hydrometer
Readme
8.0000
1 enpratnre deg.c
21.0
Comcted
} hydrometer Readme
8.0000
Effectne
Depth
(cm)
15.00
5
15
Coefficient
K
0.01369
7.0000
6.0000
Grain
Si^e
hem)
0 0175
Percentage Finer
Combined 16 99
21.0
21.0^
7.0000
6.0000
30
15.20
15.30
5 0000
001369
0.01369
.
0.0239 0 0138
14.81 1 69
21.0
5 0000
60
15.50
0.01369
4.5000
0.0098
10 58
21.0
4.5000
250
15.50
3.5000
0.01369
0 0070
9 52
21.5
3.5000
1440
15.70
2.0000
0 01332
.
0.01169
0 0013
7 4Q
21.0
2.0000
1600
n nnu
A 71
Grain Size Distribution Curve,BSiW
/MZ6* rWMV fr*'A
, )ert. Nile Imgiiuon and DwJnjge projw
rrt . Ibkrow
a
tion: Dam Site
<■■ Wn. UBDP4, Laver-A
Water Works Design and Supervision Enterprise Laboratory
Service
Soil A Material Testing Section
Sam. No:
Sim. Type Dufuxbed
Test Type Double Hydrometer Dire r 26/05/10
Grain $iz« Diatribullori Curv»,B5
1D0 00
90.00
C   80   00
c 70 00
6000
&     50.00
£     4U.C0
8  30  00
£ 20 00
100Q
ox
4^ — r--h-
with out sol’n/witti sol n * 100 = 2 8.00/S9.SD^lOO^ 13,45 %
ii
-I | _ J _i lIL | |. _ — ii r— •— —
Ir'1 “;l
I4I r
10
01
0 01
0.001
0.0001
Grain Zlze
mm
GravW
Sand
Sil
ClaynnH
$TTC £C.H MHi-fi
Ainift-f
Mzr mW h*A
x \l Z"
Project:
Client:
Location :
T.Pit. No.
Nile Irrigation and Drainage Project Hal crow
Dam Site
U13DP5. Layer A
Depth(m) 0.00 1.50
Water Works Design and
< Supervision Enterprise Laboratory Service
Soil & Material Testing Section
Sam No :
Sam. Type Disturbed
I cst 1 ypc : Hydrometer Date : 26/05/10
Total mass oj sample,
60
Steve
No
Sieve
Mass of
Sievc(&)
leifs of sieve Rtf .soi/(g)
Mass of Rrf. soil (g)
Percentage
Retained
Cttmnladvt % Retained
Percentage Passtn^
No 10
2
551.1
551.1
0.00
0.000
0.00
100.00
No 16
1.18
558.9
559.4
0.46
0.841
0.84
99J6
No 30
0.6
516.7
519.1
*> j ?
4.425
5.26
94.74
No SO
0.3
488.2
490.6
2.37
4.331
9.59
90.4 f
No 100
0.15
481.9
485.0
1.07
1.955
11.55
88.45
No 200
0.075
459.2
460.2
0.98
1.791
13.34
86j66
pan
425.5
425.5
000                 0.000
0.00
000
Hydrometer Analysis
•tijic G rat 'tty o) soil
2.65
Test Tenn
\ des.c 22
F. lapsed
Time
(mm)
Actual
I lydrome/cr
Reading
Tenprofxn
Corrected
I ly drome ter
Reading
Effective
Depth
(cm)
Coefficient
K
Grain
Siqe
(mm,
Percentate |
Fmrr
Combined
2
4X5000                 22.0
41.5000
9.50
001345
0.0293
76.19
5
44.0000
22.0
38.0000
10.10
0.0134 3
0.0191
69.77
15
40.0000
22.0
34 0000
10.70
0.01543
0.0113
62.42
30
38.0000
22.0
52.0000
11.10
0.01343
0.0082
58.75
60
36.0000
22.0
10.0000
11.40
0.01343
0.0059
55 08
250
30.5000
22.5
25.0000
12.20
0.01325
0.0029
45.90
1440
29.0000
20.0
22.0000
12.70
0.01374
0.0013
40)9ri ,PT Wit m
fr-’i^
iy>
X \LZ/
,\'ilc Irrigation and Drainage Project Halcrow
Dam Site
t:
[x>
uon ■
* pit. No
^):0|W-‘-30
, (IPDPS. Layer -A
To:jI *an of
Waterworks Design and Supervision Enterprise Laboratory
Service
Soil t Material Testing Section
Sim. No.
Sim. Type: Disturbed
Tat Type Hydrometer) ui th out sol'n) Date: 26/05/10
60
A/or/ of Sitw(g)
Im of hm
Rfi joity
Man of
Rr/. tool
PffWtfa#
Retard
Cj^fttiatw
9 j Rrfjifitd
Ptrwtlay
Panw
"a^o
2
551.1
551.1
000
0.000
0.00
10000
1.18
5)8.9
5)9.4
0.49
0.895
0.90
99.10
'^r
0.6
516.7
5189
2.22
4.057
4.95
95.05
0.3
488.2
489.9
1.72
3.143
8.10
91.90
.Vi 100
0.15
481.9
482.4
0.53
0.969
9.06
90.94
.VuW
0.075
459.2
459.8
0.60
1.096
1016\
89.84
425.5
425.5
0.00
0.000
0.00\
0.00
r.
/j
Attita/
T'tftpoaiare
CarrtiltJ
Efftttot
CatfiaMt
•—" Gnu*
Perrerttf
Tare
HytirMHter
Rtaatr.^
HydrwMrr
Reo/ty
Dtpih
fart
K
liter
Contbtud
2
25.0000
21.0
25.0000
1220
0.01349
0.0333
45.90
5
20.0000
21.0
20.0000
13.00
0.01349
00218
16.72
15
16.0000
21.0
160000
13.70
0.01349
0.0129
29.38
W
110000
21.0
13.0000
14.20
0.01349
0.0093
23.87
60
10.5000
21.0
10.1000
14.60
0.01349
0.0067
19.28
^250
7.0000
21.5
7.0000
15.20
0.0/MH
0.0033
12.85
.J44O
4.0000
21.o\
4.0000
15.60
0.013491
0.0014
7.34
Grain Sae tXalrlbutfoo Curw.BS
—non FLW
+ttc pnni-fd
Al07rt-+
MZz7 rinJW hVA
Water Works Design and
, Supervision Enterprise Laboratory
j
Service
Soil & Material Testing Section
Project :       Nile Irrigation and Drainage Project
Client:          HaJcrow
Location :     Dam Site T.Pil No. UBDP5, Laycr-A
Dcptli(m) ; 0.00 1.50
Sam. No .
Sam. Type : Disturbed
Test Type Double I iydrometer Date: 26/05/10
Grain Size Distribution Curve.BS
10000
*    90    00
c   80   00
c 7000
6000
50 00
c 40 00
S 30 00
£ 20 00
WOO
0 00
10
01
0 01                    0 001 0 0001
Grain Zize
mm
Gravel
Sand
Silt
Clay
Tejfed by :__ _ CJwkid by_
*
A>- r_ 
_" Tr. jrcJtt wtt* j
rue rtnt-K nu
% Water Works Design and Supervision Enterprise Laboratory
Service
So// & Materiel Testing Section
Nile I mgs non and Drainage Protect
r^1
Sam. No •
_
.^on: P^
c
H dcrow S,,e
rftu
I’BDPL Bulk Sample Whole Depth : 0.00-3.00
Toto/mat j
Sam. Type: Disturbed Test Type: Hydrometer
Date: 26/0S/10
Jfrt*
Sieve
|jyp
_
Mass of  4 5unfa)
ojj of neve
Man of
KeS. joii
Permito#
ReLumd
CmtimOx
% Rrtouted
PmfffUft
Pisnn^
551.1
551.1
000
0.000
0.00
100.00
5a M
1.18
538.9
538.9
0.04
0.069
0.07
99.93
0.6
516.7
516.9
022
0.382
0.45
99 55
Vi 50
0.3
488.:
490.4
2.16
3.755
4.20
95.80
Vi too
0.15
481.9
487.6
5.74
9.972
14.18
85.82
M.W
0.075
1592
464.9
5.70
9.905
24.08
75.92
425.5
425.5
0.00
0.000
0.00
0.00
Hydrometer Analyut
Gwfr 0/ tot/ 2.84 
Tut Ttfapmisn, dq.t 22
Styxa
Time
'vm
Aetna/
HyJnsveter
Reddug
Tatprafart
Cameled
HjdniHttr Reaain^
Effect™
Depth
<aa)
CtxfiwJL'
K
Gnvn
s*
(HNS)
PtrrtnLif' Enter
Com hud
34.5000
22.0
285000          11.60
0.01264
0.0)04
47.58
5
325000
22.0
26.5000
11.90
0.01264
0.0195
44.24
15
29.0000
22.0
25.0000
1250
0.01264
0.0115
38.40
50
27.5000
22.0
215000
1280
0.01264
0.0081
35.90
50
26.0000
22.0
200000
15.00
0.01264
0.0059
33.39
250
24.0000
22.5
18.5000
15.20      0.01247
0.0029
30.89
_ 1440
20.5QOO
20.0
15.5000
14.10
0.01295
0.0013
22.54
Grain Size DiitnbuUon Curve,BSnm-M PtFf
•t»TTC PMA-li
rax/r ^t/7£-os wa
u
Water Works Design and Supervision Enterprise Laboratory
Service
Soil & Material Testing Section
Project:
Client:
Location:
T.Pn. No.
Nile Irrigation and Drainage Project
I laicrow
Dam Site
L’BDPL Bulk Sample Whole Depth
Dcpth(m) : 0.00-3.00
Total mass oj jam/
(e,
Sam. No :
Sam Type : Disturbed
Test   Type   1   lydromeier(with   out     ,ol.   . Date : 26/05/10
60
57rvr
Nfl
Sieve
Mass of
Sieve(g)
Iojj of sieve
Rrz
SI ass of Krz. soil (g)
Pent n tape
Retained
Curntt/afm Retained
Pemntape
Patient
No 10
2
551.1
551.1
0.00
0.000
0 00
100.00
No 16
1.18
538 9
538.9
0.04
0.069
0.07
99.93
Ko 30
0.6
516.7
516.9
0.21
0.365
0.43
99.57
No 50
o.r
488.2
490.3
2.11
3.666
4.10
95.90
No 100
0.15
481.9
487.5
5.56
9.659
13.76
86.24
No 200
0.075
459.2
464.5
5.25                9.121
22.88
77 12
pan
425.5                 425.5
0.00                 0.000
0.00
0.00
fee Gravet) oj soil
2.84 
Hydrometer Analysia
Test Tempera fan, det.c 22
Elapsed
Time
mm.
Actual
/ lydrometer Read/np
Tenpni/ure
de^.i
Corrected I
/ iy drome ter
Reading
Effective
Depth
(cm)
Coefficient
K
Cram
Si^t
< mm}
Percentage ] Pence
Combined
?
12.0000
22.0
120000
14.30
0.01264
0.0338
20.04
5
7.5000
22.0
7.5000
15.10
0.01264
0.0220
12.52
15
4.5000
22.0
4.5000
15.50
0.01264
0.0128
7.51
30
3.5000
22.0
3.5000
15.70
0.01264
0.0091
5.84
60
3.0000
22.0
3.0000
15.80
0.01264
0.006 5
5.01
250
1.0000
22.5
1.0000
16.10
001247
0.0032
1.67
1440
0.5000
20.0
0 5000
16.20
0.01293
0.0014
0.S3'
Grain Size Distribution Curva.BSlirn1'
.x-suon ‘ ;pi< S'o ^pLh(mj
^9’T WW
MFtfA
fl7Qlfr+
rU?£lV’' h*’A
Nik Irrigation 2nd Drarugc Project
I Ultron
Dam Site
LJHPP1. Hulk Sample Whole Depth 0.00 3.00
Water Works Design and Supervision Enterprise Laboratory
Service
Sort & Materia/ resting Section
Sam No:           _
Sim. Type: Disturbed
Test  Type  Double  FIydreimeter Date 26/05/10
Grain Slza Dlttributipn Curva.BS
100 00
St  9000
w  60  00
1  70  00
“■  60  00
|      5000
£  40  00
J  30.00
£ 20 00
1000 ooo
r
—             - pr-TF ~
1 Pl I
on
i.
with out sol'n/wiih sol'n * 100 = 4.00/33-00* 100 = 12.12%
-i-l--—ir n ■ -mtn-r ~
to
0.1
0D?
0 001 0 0001
Grain Zii«
.mm
Gravtl
Sand
SIR
Clay
kp______non
jvum
♦ttc jrctft mntfd
H/JJW kVA
Nile Irrigation and Drainage Project
Hale row
Dam Site
CBDP2, UyerC
Water Works Design and Supervision Enterprise Laboratory
Service
Soil & Material Testing Section
Project :
Client:
Location
T.Pil No
Dcpth(m) : 0.40 2.00
Total mass of sample, y
Steif No
No   10
No 16
No 30
No 50
No 100
No 200
pan Elapsed
Time i min.
5 15 30 60 250 1440
Steif OpffwijdfNm)
~2
lass nJ sieve Ret .sotlfpj
551.1
Mass oj Ret, sod fg)
Sam. No 
Sam. Type : Disturbed Test Type I lydrometer
Date .26/05/10
60
Percentage
% Retained
0.00
539.7                  0.83 518.7
490.6
483.7
460.9
425.5
Hydrometer Analysis
Retained
0.000 1.398 3.352 4.043
4.75
8.79
3.032                 11 83
2.898
0.000
14 72
0.00
-•Ictteal I [ydrometer
Reading 43.0000 41 (83QQ 38.5000 37.OQQO 35    0000
31.0000
29.5000
Mass   of Steve
551.1 538.9 516.7 488.2 4819
459.2
425.5
2J7
Venpratnre
deg.c
22.0
22.0
22.0
22.0
22.0
lest 1 empergfare, depc 22
Corrected Hydrometer
Reading
37.0000
35,0000
32.5000
31.0000 29.0000
22.5 25.5000
20.0\ 22 5000
Efiectivt Depth
10.20 10.60
11.00
11 20
11.50
12.10
Coefficient K
0.01289
0.01289
0.01289
0.01289
0.01289
0.01272
12.60           0.01318
Grain Si~e [mm i
0 0291 0.0188 0.0110 0.0079 0.0056 0.0028 0.0012
5860_ 5525 51.21 88.17 85.28
0.00
Pmrrutogc
/'iner
(..ombtned 60.74
47.60
41 86
36.93
Grain Size Distribution Curve.BS
100  00
90  00
80  00
70 00
60  00
50  00
40  00
30  00
20 00
1000
000
4~
0.1          0          01
*0001 0-0001
Grain
z Sitt
Size.mm
Clay
luted by. 'fa-
Checked by :_____
Approtfd by :__;; n £
Water Works Design and Sj iupGrv‘S'on Enterprise Laboratory
Service
So*/ & Material Testing Section
:
Jcn,; Luciot10: f.pit- No-
Dtpdi^)
Mile Irnpratiof’ and Dratnagr Project Hsl<T°w
Dam Sire VBDP2. Laver C
0,40-21*0
7 &!a/ ma/f fl/
Sim. No ;
Sam Type Db curbed
1 cit Type ; Hyilrometrr(wiih out soln) Date: 26/05/W
60
J7ri*
Jiw
.\itifj of
5rti*(p.)
tajf or j, nt
r
Rj/
Moss q/!
R//. W
PrnwrAj^r
R/yxrcJ
R/Zj/wj1
Pfrtfftlog
Pawing
£.
5573
5513
0.00
0.000
0.00
100.00
.Vj 16
T5T
t.18
538.9
539.7
0,78
7314
13/
98.69
0.6
576.7
5/8.4
1.72
2898
4.21
95.79
03
488.2 \
490.3
230
3 538
7.75
92.25
X'( ’00
0.15
48/9
483.6
1.65
2.780
10.53
89.47
’Ro 200
0.075
459.2
460 7
1.51
2.544
73.07
86.93 '
425.5
425.5
000
0.000
0.00
aoj]
Hydronic tec Analysis
,’wj5 Gw:;:
2.77 
Tut Ttaptrafitn, ikr,i 22
ri      * Tawx
3itwi
I IjdnMHt/tr
RMdins
Cwndtd
J Jydrcwefrr
R/Jrfi/jr,:
Ejtrfnt
Dtp/h
Cotffiaf/H
K
Groin
Ji
fww I
' Prrrfir/tfjr ftwr
ConbimJ
2
12.5000
22.0
/ 2.5 W0
74.20
0.0/289
0.0343
20.52
5
9.5000
22.0
9.5000
74.70
0.0/282
00227
15. 59
15
5.5000
22.0
5.5000
75,40
0.0/289
0013/
9.03
30
4.0000
22.0
4.0000
75,60
00/289
OOC93
6.57
tffl
3,0000
22.0
3.0000
15.80
0.0/289
00066
4,92
_
JUQ
2.0000
22.5
2.0000
’5.00
0,0/272
00032
3.28
1.0000
20.0
1.0000
’6.10
0.07318
0.0074
7,64
Gr«ln Slit Ol^trltMjUon CuCrt.BSnm-H              anji'v1;
js-cjh- pnntf a
MQ1A-+
MX£- FWMtrfiv hVA
Project : Nile Irrigation and Drainage Project
Client Halcroxv
I station Dani Site
T Pit. No. UBDPZ, Layer-C
Depth (m) : 0.40-2.00
Water Works Design and Supervision Enterprise Laboratory
Service
Soil 4 Material Testing Section
Sam No :
Sam Type ; Disturbed Test  Type   :  Double  Hyd
Date : 26/05/10
rometer
Grain Size Distribution Curve.BS
100 00
90 00
£         8000
C  70  00
^   60   00
&   50   00
c 40 00
30 00
£ 2000
1000
000
lip' J
with out sol'n/with sol 4.00/46.50* 100 = 8.6(
fin o
Ll j_Li J_r lr'1i —*■
10
0 1                    0 01
0 001 0000-
Grain Zize
mm
Gravel
Sand
Silt
Clay
4
y
I■ Approved b)
♦
/Zz-
,.//■ rv/*"' "'
Water Works Design and
£■ Supervision Enterprise Laboratory
Service
Sor/ 4 Materia, Testing Section
S,]e Irrigation and Drainage Project
Halonw
Dari Site
l’pnF2, Layer B
. (1.111-0.411
J'oW/ CTrJf J >/ Wgf»/f,_
Sim. No •.
Sim Type : Disturbed Test Type : Hydrornriet Due: 26/05/10
60
fjpr
J/rw
MdJJ oj
SuwfyJ
fair of rret-t
R/r jaJfy
Mart of
Re/, uh/ (&)
Retaifttd
fjrfflwir/jrr
% Rtfujia/
Pfftfnfotf Pajjrn^
>___
2
551.1
35f.i
0.00
0.000
0.00
100.00
tJ
■Vr FZ
,w/  _
tJi
538.9
540.8
1.88
3.730
3.73
96.27
n i nJ _ Aa 50
0.6
516.7
524.1
7.42
14.722
18.45
8JJ5
0.3
488.2
494.4
6.24
12.381
30.83
69.17
t/W
0J5
481.9
483.6
1.68
3,333
34.17
6fSj'
7j2W
0.075
459.2
460.4
1.24
2 460
36.63
63.37
MT
425.5
425.5
0.00
0000
000
GM
Hydrometer Analyiii
1
i)tf£ Cwt/j of toil
2.72
TerfTfrnpmtm, dt^c
22
Twr
AOim/
I [)(irurrft!€>
RAMfrg
Tefip/uiw
fy-c
Comcted
, / lydrvmtftr
RrtfJfrg
kflwtivt
Dfpt/i
fem)
Cwffuttitf
K
Crain
Sr^t
fww
Permittee
Friwr
Combined
2
33.0000
22.0
27.0000
If 90
001307
00319
52.75
5
32.0000
22.0
26.0000
12.00
0.01307
0.0202
50.80
/5
30.0000
22.0
24.0000
12.40
0.01307
0.0119
46.89
30
28.5000
22.0
22.5000
12.60
0.01307
0.0085
43.96
__ 60 
27.5000
22.0
21.5000
12.80
0.01307
0.0060
42.00
_ 24.5000
22.5
19.0000
15.20
L JUQ _
0.01290
0.0030
37.12
2 f. 0000
20.0
14.0000
14.00
0.01337
0.0013
27.35
Grain Sh* Distribution Curve,BSnm-i
«TTC ttCJH- PHRA-fA
Mxr r-utJW hVA
Water Works Design and
, iupervision Enterprise Laboratory Service
So// & Materia/ Testing Section
Project :
(Client:
1-oca bon :
T.P11 No
Nile Irrigation and Drainage Project
Halcrow
Dani Site
UBDP5. layer-A
Dcpth(m) 0 00-0.85
Sieve
Total most 0/ samble. r
n------- -—1 z
Sam No :
Sam Type : Disturbed Test Type ‘ Hydrometer
Date 26/05/10
60
Xtasj of
RfZ. soil (PJ
Perven rage Retained
Aa 16
No 30
No 50
Ao 100
Ao 200
: .n
Apetifh C,raviy oj jqiI
2 1.18
0.6 0.3
Staff of Steueff)___
551.1 538.9 516.7 488.2
0.00                0000
1 97
3.29
2.38
0.15                481.9
3.297
5.505
3.983
0.075
lasj of sieve Ret .fot/(r)
551.1 540,9
520.0
490.6
482.8
460.1
0.99                 1.489
459,2
425.5
0.88
1.473
Gnmulativt % Retained
0.00 J. 30
88(f 12.78 14.27 15.75
0.00                0.000                  0.00
Hydrometer Analysis
Elapsed
2.60 Tenprature
ty.c
22.0
22.0
22.0
22.0
22.0
22.5
Conwed Hydrometer
Readin. 41.5000 40. 5QQQ 39 0000 37.5000 37.0000 35 0000
ISl1 1 
( ^efficient K
00/353 00135f 0 0/353 001353 0.01353
dey.c
7; wr
Actual
H ydrvmeter
fwr/r J
Reading
47.5000
46.5000
45.0000
43.5000
4J. 0000
40.5000
Effective Depth fem <
9.50
9.60
9.90
10.10 10.20
39.5000
20.0 32.5000 11.00 0.01386
Grain Size Distribution Curve,BS
10.60           0.01337
Grain Siqt (rnm
0 0295 0.0187 0.0/10 0.0079 0.0056 0 0028 0.0012
Percentage
Pa/jjirg
100.00 96 70
91.20
87.22
85.73
84.25 0.00
22________ Ptnentage
Finer Tombinta
70.26 68.57
66.01
63.49
62.64
59.26 55.03
&
c
a>
e
0)
CL
/ es/ed try : Checked Ennf’l
ww
wiH
x '-/y
Waterworks Design and Supervision Enterprise Laboratory
Service
So// 4 Material Testing Section
Tpjiec’; O”1
y.Pit.Nf
pcpitifm
Nile  Irrigation  and  Brainage  Project [ laicrow
Dam Site
L'BDl’5, Layer-B 1.50-150
Total man
Sum. No r
Sarn. Type : Disturbed Test Type ■ Hydrometer Date: 25/05/10
50
J’rrX
No
Si fir
OfW ’ •*'
Mast rf
Sicw(tf
•fdiJ fl/ jrrvf Rd .hh/%1
Mat? of
Rm. josi
Pmnfa^e
Cjrwivitfrt r
% Rdamed
I Pfnfatajt Pdfftft
2
&.i
55 Lf
OM
0.000
0.00
100.00
7.7#
5383
5 40.2
1.29
2764
2.76
9724
~XtJ0
0.6
5 It J
5203
537
7649
10.41
89.59
\n50
03
488.2
490.7
2.48
5314
15.73
8427
’ x» 100
0,15
481.9
483J
1 19
2.550
18.28
81.72
X»200
0.075
4592
460.2
1.01
2164
20.44
79.56
425.5
4253
0.00
0000
000
0.00
Hydrometer Analysis
2
■firry/jOT, d^Rr
EupjcJ
Tmc
3d vol
1 i ydrwrf&j- Rnxdrjv|
Tt^pralMn
Comtlcd
1 lytlnwrfte?
Rradin.
Efatinf
DtpiA
Cotflifif*/
K
G/axfl
J7^r
PrrvrMqge 1
J juwr
-
Cpfnbirwd
X
72.(X7OG
21.5
J6OO00
10.20
0.01353
0.0306
78.05
5
40.0000
21.5
34.0000
10.70
0.01353
0.0198
73.71
l J.L
37M0Q
21.5
31.0000
1120
0.0/353
OOH 7
6721
MJW0
21.5
28.5000
11.60
0.01353
0.0084
61,79
60
32 5000
213
26.5000
1590
001353
0.0060
57,45
2$0
29.5000
22.0
23 5000
12.40
0.01353
0.0G30
50 95
_ 1440^
25.0000
21.0
183000
1320
0.01369
00013
4011
Grain S<<* Distribution Clmv»,BS
I
E
£
3
c
4.
100 00
BQ 00
80 00
70 OD 00 0C 5OQQ
40.00
30 00
20 00
10.00
0.00
1CpmH
*TTTC
A101fr+
rAX/7 WUM? h^A
Tel 251 -116 - 18 55 16/61 45 01 Fax 251 -116-61 53 71/61 08 98
e-mail w.w.d.s e@ethio.net et
Project : Nile Irrigation and Drainage Project
Client:         Halcrow
Location :    Dam Site
Test Pit: UBDP1, Bulk Sample Whole Depth
Depth(m): 0.00-3.00
Water Works Design and Supervision Enterprise Laboratory
Service
So// <S Material Testing Section
P O Box 2561
Addis Ababa
Ethiopia
Sample No
Sample type : Disturbed
Test type : Standard Proctor
Date 02/06/10
Lab test No
1
2
3
4
Water in cc
100
200
300
400
Wt of mould + Wet sample(g)
3365
3639
3584
3524
Wt of mould (g)
1732
1758
1732
1758
Wt of wet soil(g)
1633
1881
1852
1766
Volume of mould cm3
944
944
944
944
Wet Density g /cm3
1.73
1.99
1.96
1.87
Moisture content
fin No.
23
CD
A6
39
Wet soil * tin (g)
105.66
112.09
102.75
129.15
Dry soil + tin (g)
92.98
94.88
84.26
99.98
Wt of tin (g)
16.13
16.72
17.03
16.31
Wt of Water (g)
12.68
17.21
18.49
29 17
Wt of Dry soil (g)
76.85
78.16
67.23
83.67
Moisture content %
16.50
22.02
27.50
34.86
Dry Density g /cm3
1.48
1.63
1.54
1.39
Zero Air Voids 100%
1.93
1.75
1.59
1.43
MDD : 1 635gm/cc OMC : 22.50 %
15 17 19 21 23 25 27 29 31 33 35
Water Content %
TESTED BY:- CHECKED BY :- APPROVED BY :-
£          0P
If           \-jjmT RHjn ? *TTTC
1
Mltfi A™™-*
Tel 251 - 116- 18 56 16761 45 01 Fax 251 - 116 - 61 53 71/61 08 90
e-m«H w.w.d s.o@ethio.n©Let
r
project Client Location
Test P't Cepth(rn)
Nile irrigation and Drainage Project Hatcrow
Dam Site UBDP2, Layer C g 40-2 00
Water Works Design and Supervision Enterprise
Laboratory Service
So// 4 Material Testing Section
P O Box 2561
Addis Ababa
Ethiopia
Sample No
Sample type Disturbed Test type Atterberg Limit Dale 26/05/10
LiQUfD AND Fl-ASTlC LIMIT qE term NATIONS
oxta and compilation SHEET
jType 0< teal
LL
LI
LL
LL
Ccnlr^e* No
F
60
T
M4
Ms or Bio**
34 0
28.0
22.0
16.0
■M of sampi e * T sxe wet
34 490
34 BOO
35.890
34 020
Wtof sample * Tare dry
27.530
27.620
28 300
27 240
W of urate*
6.560
7.180
7 590
6.780
Tat
17 110
15 990
16 160
16.940
tftof dry so4
10.820^
11 630
12.140
10.300
Waler content %
60 628
61 737
62.321
65 025
PL
PL
ICcnlehtr No
C7
M11
of 5 ample + Tare wet
27 970
28 740
of sample • Tare dry
24 700
25 270
|Wl gi water
3 270
3 470
[]aie
16 550
16900
Cry loti
B 150
8.370
l W«*rcan|enl X
40 123
41 458
40 791
Flow curve
66 000
£  55  000
a &4 W0
8  63.000
I 62 000
o 61 000
60 000
Results
LL= 62 20% PL- 40 79% Pl= 2141%
too                       25
1000
No of Blowspm4 nW
♦TTTC
JTCtft Ulir+d A701 ft-+ MX£* yt/XCTM’ ft^A
Tel 251 - 116          18 55 16/61 45 01 Fax. 251 - 116 - 61 53 71/61 08 98
e-mail w.w.d.5.e@ethio.net.et
Project       Nile Irrigation and Drainage Project Client         Halcrow
Location Dam Site TestPrt: UBDP1
Depth (m): 0.00-3 00
l IQUID AND PLASTIC LIMIT DETERMINATIONS
DATA AND COMPUTATION SHEET
Waterworks Design and Supervision Enterprise
Laboratory Service Soil & Material Testing Section
P.O Box 2561
Addis Ababa
Ethiopia
Sample No
Sample type Disturbed Test type . Atterberg Limit Date 26/05/10
Type of test
LL
LL
LL
Conteiner No
47
A8
LL
9
200
No of Blows
34.0
28.0
220
160
Wl.of sample * Tare wet
38 490
34 090
34 460
37 660
Wt of sample > Tare dry
31 660
28 440
28 570
30770
Wt of waler
6 830
5.650
5 890
6 890
Tare
16410
16 290
16 230
16 610
wt of dry soil
15 250
12 150
12 340
14 160
Waler content %
44.787
46 502
47 731
48658
PL
PL
Conteiner No
39*
G-6
Wt of sample + Tare wet
2 8 840
29.120
Wt Of sample ♦ Tare dry
26 170
26 350
Wt of waler
2.670
2.770
Tare
16 350
16 290
wt of dry soil
9 820
10 060
Water content %
27.189
27 535
27 36]
Flow curve
Results
LL= 73 88% PL= 27.36% PI = 46 52%. *TTTC
i
(hit
Tel 251 - 116- 1855 16/61 4501 FaM 261- 116 61 53 71/61 08 98
Waterworks Design and Supervision Enterprise
Laboratory Service
Soil & Material Testing Section
P O Box 2561
Addn Abate
project C*n>' Location
T«tW
,-mall w.w.d ».««ethlo n.tet
Nile Irrigation and Drainage Project Halcrow
Dam Site UBOP4.Layer-B
Depth (mV
l- 1 80-2 00
Ethiopia
Sample No
Sample type Distorted Test type Atlerbeg bmit Dale 27705710
( q|j|O AND PLASTIC LIMIT
D £TERWN*ti0NS
j»IA ANO COMPUTATION SKET
'Type Di toil
LL
LL
LL
LL
Ccrtetw No
V
3
J
P5
Mo of Blews
34.0
280
22.0
16 0
Wlof w cl® •Tire wet
rr
37720
37 200
37 340
37410
Wo» liH-olt • Tare dry
30.820
30 470
30 500
30 350
Mot water
6 900
6 730
6 840
7 060
Trr
16.640
16 990
16860
16 290
&0* dry tod
14 180
13 480
13640
14 060
|V»er content %
48660
49 926
50147
50213
PL
PL
|Con(einef No
M12
c
Mol umpie* Tare wet
29 440
30 820
VoiMnoe ♦ Tare dry
26 640
27 600
Mol water
2 800
3220
’>e
16280
16 400
W Cl dry jot
10360
11 200
'A’Jfer content %
27 027
28 750
27 89
Results LL= 49.90% PL= 27 89% Pl= 2201%fan rtPT vims *tttc
rM.c
Project Client Location Test Pit Depth (m)
rtDJW h<£A
Tel 251 - 116 - 18 55 16/61 45 01
Fax 251 - 116 61 53 71/61 08 98
e-mail w.w.d.s.egethio.netet
Nile Irrigation and Drainage Project Hale row
Dam She UBDP3,Layer-B 0.85-2 00
Water Works Design and Supervision Enterprise
Laboratory Service Soil A Material Testing Section
P O Box 2561
Addis Ababa
Ethiopia
Sample No
Sample type Disturbed Test type Atterberg Limit Date 27/05/10
LIQUID AND MASTIC LIMIT
determinations
DATA AND COMPUTATION SHEET
Type of tesl
LL
LL
LL
ll                              I
Contemer No
A9
23’
23
A18
No of Blows
36 0
300
24 0
180
Wt of sample > T are wot
35.710
34 060 1
35 270
36.330
Wt.of sample ♦ Tare dry
28420
27 400
27 820
28.620
Wt of water
7 290
6 660
7 450
7 710
Tare
16 440
16 540
16.110
16.730
wtof dry soil
11.980
10 860
11.710
11 890
Water content %
60 851
61 326
63621
64 844
PL
PL
Contemer No
92
C7
Wt.of sample * Tare wet
28.390
28 480
Wt of sample ♦ T are dry
25 540
25.560
Wt of water
2.850
2 920
Tare
16.270
16 560
wt.of dry soil
9 270
9000
Water content %
30.744
32.444
31 59|
Flow curve
65 000
-
64   000
Resul
ts
c
63   000
LL=
62    75%
o
£
PL=
31.59%
62.000
pi =
31 16%
•   61   000
o
3 60 000
100
Tested By Checked By_ Approved By
a
25
100 0
No of Blows
1r oT ri-S’T WH ♦TTTG JTCJH 'Uld-td A707A.+
wim/w xxiz>
Tel 251 - 116- 16 55 16/61 45 01 Fax 251 - 116 - 61 53 71/61 08 98
• mail w.w.d s egethio n«t.et prajecf   Nile Irrigation and Drainage Project dent       Halcrow
Location Dam Site
Test Pit UBDP5,Layer-B Depth (m) 1 50-2 50
jOUIDAND PLASTIC LIMIT DETERMINATIONS
DATA ANO COMPUTATION SHEET
Water Works Design and Supervision Enterprise
Laboratory Service
Soil & Material Testing Section
P O Box 2561
Addis Ababa
Ethiopia
Sample No
Sample type Disturbed Test type Atterberg Limit Date 27/05/10
T»pe ol lest
LL
LL
LL          L-ll.
•CorJerei No.
Gl
TG
42
A20
Mo ol Blows
34.0
28 0
220
16 0
•vtofsarr^e ♦ Tare wet
35 460
35690
37 080
33 920
At of sample ♦ Tan? d»y
28860
28.970
29 780
27 480
Iwiofweter
6.600
6 720
7 300
6 440
—
16 120
16280
16 480
15 930
ft. of dry sod
12.740
12 690
13.300
11.550
Water content %
51 805
52 955
54 887
55 758
Pl
PL
Conremv No
39’
J
Wt or sample ♦ Tare wet
30 450
30.790
WLof sample • Tan dry
27 320
27.460
iWlot water
3 130
3 330
lire
16.330
16 350
dry sot
10 990
11 110
j>'«er content %
28 480
29.973
2923|
Flow curve
Results
LL= 53 60% PL= 29 23%
PI = 24 37%POPi pvt* Jtm ? HTTTC
1
j?cJH
HfiMf ma
Tel 251 - 116-18 55 16X51 45 01 Fax 251 - 116-61 5371/61 08 98
e-mail w.w.d.s.e@ethlo.net.et
Project       Nile Irrigation and Drainage Project Client:        Halcrow
Location . Dam Site
Test Pit UBDP4,Layer-A Depth (m) 0 00-1 80
LIQUID AND PLASTIC LIMIT DETERMINATIONS
DATA AND COMPUTATION SHEET
Waterworks Design and Supervision Enterprise
Laboratory Service Soil & Material Testing Section
P.O.Box 2561
Addis Ababa
Ethiopia
Sample No
Sample type Disturbed Test type Atterberg Limit Date : 31/05/10
Type of test
LL
LL
LL
LL
Container No
B-8
B-11
E
C9
No of Blows
36 0
30 0
24.0
180
W. of sample + Tare wet
36 880
35 720
37 340
35.960
Wt of sample ♦ Tare dry
29 300
28 530
29 490
28 570
Wlof water
7 580
7.190
7 850
7 390
Tare
15 920
16 170
16 290
16 570
wLof dry soil
13 380
12 360
13200
12.000
Waler content %
56 652
58.172
59 470
61 583
PL
PL
Container No
2
N
W of sample + Tare wel
30 160
29 800
Wt of sample ♦ T are dry
26 570
26.520
Wt of waler
3 590
3.280
Tarn
16 100
16.740
wtof dry soil
10470
9 780
Waler content %
34 288
33 538
33 91 I
Flow curve
Results
LL= 59.07% PL= 33 91% PI = 25 16%
10 0
Tested By Checked By Approved By 
25
No of Blows
100 0
j—
/X/Z^z.
X* //
-
3f. v X
*
A.
I
••
z. i
n
X- * /♦
5*
,«rfBV
♦TTTC
jrctt Ifld-fd A707IH r^i: ru)JW hvA ' X i
Tel 251-716 18 55 16/61 45 01 Fax 251- 116 61 53 71/51 08 98
e-mall w.w.d.s egethlo neLet
Waterworks Design and Supervision Enterprise
Laboratory Service
Soil A Material Testing Section P.O.Box 2561
Addit Ababa
Ethiopia
Project Nile Irrigation and Drainage Project Ctert     Halcrow
Location Dam Site
Test Pit . UBDP3.Layer-A Depth (m) 0 00-085
UXM) AND PLASTIC LIMIT
^TERMINATIONS
OVA ANO COMPUTATION SHEET
Sample No
Sample type Disturbed Test type Atteiberg Limit Dale 31/05/10
[ho* 3l test
IX
LL
u
LL—i
CoMtine* No
801
s
29‘
M
No d Siows
340
280
22 0
160
Wotwripe ♦ Tiie wet
35 530
35 680
35.160
35200
o’sample ♦ Tire dry
26.130
25920
25660
25610
W,ofwili'
9 400
9 760
9 500
9 590
Ilin
16 740
16390
16510
16 460
Of (fry SOi
9.390
9 530
9150
9.150
Wa'et content %
100.106
102 413
103.825
104 809
PL
PL
bontenei No
J
39’
Wt of lampie ♦ Tire wet
27.710
27950
Ntofiample * Tan dry
24 260
24 370
'•M of water
3.450
3.580
Tare
16 380
16.350
soi
7880
8 020
L Wate< content %                 43 782
44 638
44.211
Flow curve
Results
LL- 102 55% PL= 44 21% Pl= 58 34%pmi rtPT AHin*; *tttc JtCJH MlfrH Wlfrf
Mxr
h^A
Tel 251 - 116-18 55 16«1 45 01
Fax 251 - 116 - 61 53 71/61 08 98
e-mail w.w.d a.elgethio.net.et
Project
Nile Irrigation and Drainage Project
Client
Halcrow
Location Dam Site
Test Pit UBDP2.Layer-B Depth (mJ- 0 10-0 40
LIQUID AND PLASTIC LIMIT DETERMINATIONS
DATA AND COMPUTATION SHEET
Water Works Design and Supervision Enterprise
Laboratory Service Soil & Material Testing Section
P.O.Box 2561
Addis Ababa
Ethiopia
Sample No
Sample type : Disturbed Test type Atterberg Limit Date 31/05/10
Type of lest
LL
LL
LL
LL
Conleoer No
C11
F18
ND
69
No of Blows
34 0
28 0
22 0
16 0
Wt of sample ♦ T are we!
34 030
33930
33 690
35 380
W of sample ♦ Tare dry
25910
25760
25490
26 430
Wlof water
8.120
8 170
8200
8 950
Tare
16230
16280
16 170
16.720
wt of dry SOd
9680
9480
9 320
9.710
Waler content %
83 884
86.181
87 983
92 173
PL
PL
Contemer No
C15
17
VM of sample ♦ Tare wel
28 100
28 220
Vfc.of sample • Tare dry
24 560
24 640
W of waler
3 540
3580
Tare
16 450
16 300
wt Ol dry sod
8 110
8.340
Water content %
43650
42926
43 2$0
Flow curve
I
c
o
u
e
3
z
93  000
92   000
91  000
90  000
89  000
88  000
87  000
56  000
85  000
84.000
83 000
Results
LL= 87 17°4 PL= 4329% PI = 4388%
100
25
1000fmf               AWW HTTTE
Project Client Location Test Pit
Tel 251 - 116-18 55 16/61 45 01
Fan 251-116-81 5371/81 OS 93
•-mail w.w.d.i.etgethionet.et
Nite Irrigation and Drainage Project Hale row
Dam Site
UHDP51ayer-A
Depth jmj- O.DQ-1.S0
LIQUID AND PLASTIC LIMIT DETERMINATIONS
DATA AND COMPUTATION SHfctT
Water Works Design and Supervision Enterprise
Laboratory Service Soil & Materiat Testing Section
P.O.B0I 2561
Arfdrs Ababa
Ethiopia
Sampl* Mo
Sample type: Disturbed Test type Atlerberg Limit Date 311*05/10
1>pe of I«1
IL
LL
LL
LL
C-ontS'ina r Nd
M11
B-2
22
G14
No ol 8lcwt
34 0
20 0
22 0
16.0
Wl of $*rrfjle * T are wet
36 150
34 290
35 820
32.880
VW-fll sample + Tare dry
28 800
27.450
28.080
26200
VW_ol wife*
7 350
6.040
7 740
6680
Tire
16 890
16 750
16.270
16.150
wtal dry soil
11 920
10.700
11 610
10 050
Witar content %
61 661
63 925
65 538
66 468
PL
PL
CcKiteiner No
16’
61
W of sample » Tare wel
28.850
2B 190
V^ .of MHipte * Tw <1 ry
25.630
25.160
VW.of wales
3 220
3 030
Tam
16.380
16270
*1 o£dry sort
9.250
8 090
Waler content %
34 811
34 M3
34 45 I
Flow, curve
Results
LL=_63JM% PLte     34   45% PI =      29-49%
No of Blows
Tested By QJ
Checked
Approved B
IWW 'PTTC
MW-*
W ater \N ovka Design
Supervision Enterprise
Laboratory Service
Fm  251 - 116-61 53 71/61 08 98 e-mail w.w d s.eQothionet et
p O Box 2561
Consultancy Senses for BO.OOOha
Location: Negao
-------- ■ ^annooha Te»t Method: Hydrometer>cld nautralazalon, Oi,ln K.,
Amm_L ‘Mn’ K»*hl
Feas^ySfody----------
F^rORATORYNUMBER
2909/02 UBDP1
-------- Acela
.2910/02 2911/02
profile code
UBDP2 UBDP3 '
UBDP4
DEPTH (M)
0.1-04
Sand(%)
Silt (%)
Clay (%) Texture Class P -H O (1:2.5)
2
H
P -KCL( 1:2.5) EClms/cm)
h
(1:2.5)
Exch.Na(meq/100gm  of  soil) Exch.K(meq/100 gm of soil)) Exch.Ca(meq/100 gm of soil) Exch.Mg(meq/100 gm of soil) CEC(meq/100 am of soil) Organic Carbon(%)__________ Water Extract SO4'2 %_______ Acid Extract SO4  %_________ Exchangeable Sodium %(ESP) Bulk Density gm/ (cm) _______ Particle Density gm/ (cm)3 Available K (mg /kg soil)
Soluble Salta ( meq/l) 1:5 ext Na (meq/l)_________________ K (meq/l)_________________ Ca (meq/l)________________
!Mg (meq/l)________________
Sum of Cetions (meqllOOgm of soil)
CO? (meq/l)___________ Cl' (meq/l)
?CO? (meq/l)
SO? (meg/))
jumotAniona |meq/10Qgm of sol|)
RemarK:
Checked by
0.76
0.00024
2
3
Approved.by-—
*
t. t t.
<>1|V
-. ** y $•-
•v

Summery

Summary of Upper Beles Irrigation Project Feasibility Study

Upper Beles Irrigation Project Feasibility Study - Geology and Hydrogeology Report

Project Overview

The document is Volume 10 of the feasibility study for the Ethiopian Nile Irrigation and Drainage Project, focusing on geology, hydrogeology and geotechnical aspects of the Upper Beles Irrigation and Drainage Scheme. The project involves developing about 80,000 hectares of net irrigation area in Ethiopia, financed by the World Bank.

Key Components

Dam Site: Proposed storage dam on Upper Beles River (60-70m height, 1.1km crest length)
Command Area: Approximately 64,000-83,000 ha irrigation area
Main Canals: 100.3 km right bank canal and 131.9 km left bank canal
Other Structures: Diversion weirs, balancing reservoirs, drainage systems

Geological Findings

Regional Geology

The area is characterized by:

Precambrian basement rocks (granites and metamorphics)
Tertiary volcanic rocks (mainly basalts and tuffs)
Quaternary deposits (alluvium, colluvium)
Major structural trends: NE-SW and NW-SE

Dam Site Geology

Main formations identified:

Lithic/agglomeratic tuff (dominant bedrock)
Basalt layers/sills
Dolerite dykes
Alluvial and colluvial deposits

Command Area Geology

Key soil/rock units:

Vertisols (black cotton soils) - covering ~50% of area
Reddish brown residual soils
Basement rocks in southern areas
Tertiary basalts
Dolerite intrusions

Hydrogeological Assessment

Aquifers mainly in fractured volcanic rocks (moderate productivity)
Estimated recharge: 150-250 mm/year
Groundwater quality generally good (TDS 0-1500 ppm)
Existing wells and springs provide local water supply

Key Recommendations

Additional ground investigation needed for detailed design
Further studies on fault zones at dam site
Assessment of construction material sources
Monitoring of groundwater impacts from irrigation

Document Structure

The full report contains 14 chapters and multiple annexes including:

Geological maps and cross-sections
Ground investigation data (borehole logs, trial pits)
Geophysical survey results
Laboratory test results
Hydrogeological data