THE FEDERAL DEMOCRATIC REPIRUC IF ETHIOPIA MINISTRY OF WATER RESOURCES ArjoDedessa Irrigation Project Feasibility Study Report VOLUME - III Water Resources VOLUME - III (a) Annexure - 7 Meteorological And Hydrological Studies Annexure - 8 Hydrogeological Studies May. JOO? Addis Ababa CJ1 WATER WORKS OESIGN & SUPERVISION ENTERPRISE IN ASSOCIATION WITH INHHCONTINENTM CONSDITMTS IND HCHNDCMTSINDIA PVT 1TD P () Box 2S() I Addis Ababa Ethiopia To! (2^1)1 614501/6^IK9(i Tax (125I)I 61517IF.-mail u h d scaiclccom netdARJO-DEDESSA irrigation project FEASIBILITY STUDY REPORT CONTENTS OF THE REPORT SERIAL NO, 1 2 3 VOLUME NO, PARTICULARS EXECUTIVE SUMMARY MAIN REPORT Pan I - Report Part ri - Maps i Drawings ANNEXURES VOLUME -1 SURVEY AND INVETIGATION (ANNEXURES - 1 to 3) 4 volume -1 Topoyaprxc Survey Geomorphoiog»cai Studies & Geological & Geolecnmcai investigation Part I - Report 5 Volume -1 (Pi Part ii - Appendices 6 VOLUME -II NATURAL RESOURCES (ANNEXURES - 4 Io 8| Forestry Energy & Catchment Development Plan VOLUME -in WATER RESOURCES (ANNEXURES - 7 to 11) Volume - III (al Meteorological & Hydrological & Hydrogeological Studies Dam & Appurtenant WcX*$ Par. - Repon B volume • III (b) 9 10 volume - ill (cj 11 ■2 13 14 15 volume • ill idi VOLUME rv voiume - EV k,ai Volume * IV (bj Part II - Drawings irogation & Drainage Pan I - Report Part H - Drawings Myorauiic Structures Pan • Repon Part ll • Drawings AGRICUTLRUE (ANNEXURES - 12 to 18) So* Survey & Land Evaluation Agricultural Planning Volume • IV (cj Livestock. Fishenes Agricultural Mechanization & Agricultural Marketing VOLUME - V ENVIRONMENTAL AND SOCIO - ECONOMIC ASPECTS (ANNEXURES-19 to 25) 17 Volume-v (8) Environment Health & Sooo-econcmic Aspecn 18 Volume-v(b) Organization 5 Management Physical infrastructure Resettlement. Financial S Economic AnalysisAnnexure - 7 METEOROLOGICAL AND HYDROLOGICAL STUDIESAr}o Dcd«sa Irrigation Pn>)BCl Meteorological and Hydrological Aspects M*y 3007 Table of Contents Ta BL f Uf CONTENTS---------------.------ - ------ ------ -------------------*------------- --- -------------------------- ----- — LIST O F T A B I ESjiuiiuniuimiraiintH-n--'-"—■—■■■&■■■■■■■ 1 ■ rraimimimiEi■■■■■riiibi■■ ■■■■■■■ ■■ inBiimii-niniiEiiivniiail^ list of annex ire --------------------------------------------------------------------------------- -...u..™.—.im.r-.ir.>.-,.----!--!,- | . ll S T 03 F I'[ 1,1 11 R F, S-.. ——. L INT.R.'DDlj'CTIIO’N 1J l | uU1 .iiinrir in, 1 ll . ,auaa— a a.u.a a un aaa ■ as ■ ■ irri a r> i a a_ia a—art—■ ■ — - — .—s»™ —•- a.a a- a.a—a a.—— ... —.a.a._. - -..—. a—a,a—a,a—au — Ma -—------------------------------------------------------------------------------ ----- ,._ ,..ia.iiu;iii-iuii-iiifcjiiaiikiiijiiuiiMLMUia..u—i.aaa;;.:;—II —i a HI ■ au. I ll it Tm NIL! Basis ............ ....................»— 1 2 ABBaY DaSIN 1.1 TKt DtDESSA Cat : VMLM h 1 3 2. REVIEW OF PRE VIOLS STUDIES------------------ -----—-------------------- -----------------------------------------.----- - --------- S 2 1 LaJJMAYEA ]9ft2 STUDY .................. ...................... . .. 3 22 Land and Water Resources of the Bl u e Njle B *isd- E thkjpia S 2 J GOl^TRY wffjf Mas rfcR Pl Ah STUDIES EV DS A ’ W APCOS J19S&-VUJ t 24 STldy by BCEOM - (n association fcirMSL an(j EiRG Hfw 9 25 STUDY B t MBffISTR Y W WATER RE SOURCES FOR LOWf K Df.DESSa (2 MH J. . .. 15 2d UtilitywEajljerStudies . 16 Climatological Data .. Rain fall RD ER OISTHaRGE SLDMENT Data r IT ■■iniiTHFHi’ ii ii am in ii n iii-iii * Mi*ai> al- ■■ unii • m-iimLr ■T■■ n n ib-iii-.ii .ii ■ i ran uraiimiwai ■aiMiaiiuiiftt.i 4. ESTIMATION of reference EVAPOTRANSPIRATION 4.1 4.2 4.JJ 4:; 4JJ 4 *4 4 JI 43 ivruoDcmo* meteorological Data...................................................... ................ ..................................................... Otjrrvarjwi .^rfflTrdri-j If ■"LlJs,S!'P£Ia.k ""l Hjf ^wmr-di'n ....................................... FFjHd rpccd. Sour Aild'riirJrjuS Pl KMAS'. MONTI ITW tQL-a riDN Bln I. Lt >9 »9 2U 2i? 2j Sv *3 ira-fr-m- mi iiiain 23 24 Arjo [haera Pry/rtf Afta RAINFALL ANALYSIS--------- ---------- ZMenj Pf-yjrtt 4rr<7 30 S- 5I 5 2: S3 $4 ii nib t INTRODUCTION Ranfall Internal and external CtMKiwni Estimation of Rainf.ab i Rfb lability Level Estimation of maximi m Rainfall Fplfq* f srnv MONTHLY STREAMFLOW ANALYSIS.™—. A2 12 32 33 M 40 *. d2 HYDROLOGICAL OBSERVATION STATIONS EXTEhSki\ OF RECORDS hJ synthetic Flows -k> 4f« ■ mmmvv i iib..bi IL 47 7 estimation of floods for lingauged catchments ,..u5i 71 RrtTICfrAL METHOD 72 SCS Method ?3 n4 Transferring Gauged Data Estimation of Weighted as erase Si $3 $4 7S SYNDtR ME THOD OF CONSUL CljNr SVNTHETJT HVDROGRaFH M ss 1 FL OOD FREQUENCY ANALYSIS I Water Works Design & Supervision Enterprise [a Associate with hn«XdntiiienLaJ Cemulunis and TeetiBOcrau Pit LtdArju Messi ImfsUQo Project Meteorological and Hydrological Aspects H I IS TRHiHX i'TH>S s i estimation or Proc ABfi-rr> ft lighted mome >1 s fi J Ge> F taLtZf ft £xn?f ME \ al l t De trihl rlWh Bi LOG-LOGniK’ DtSTRBLTW- 8 5 REGIONall % aVERaGED m a vTlLES way acr? - - 59 41 &l 62 8 6 C1HCih._E Off DlSTRIBl'TICiN 63 9. IO probable maximi m flood SEDIMENT ANALYSIS 10 1 Estimation of SEftiMZNf tiEijD JD.2 DISTRIRlTPOS OF 'SEDIMENT lh DIE REST* VW *9 .. .............. 70 IL W ATE R QI A LI TY ———-------------------------- ------- - --------------------------------- ------------------------^..1J 11. DESIGN F LOO D -------------------------------------------------- ----------------------- ----- ------------- - --------- --- ------- 12-3 SWTHITK' HY^RUGRaFH ... .... . ... . . .... ... .. 7$ 12 2 FLOOD EbDUTfad TilROOCMi THE RESWMt 75 12.} Routed Desk.< Fuhjd at she CcjffffE-R D* m ’B Il RESER VOIR SIM L'LATtON^------------------------------- -------------- - ------------------------- ...---- ---------- $7 I4i DEDESS A S'L B-BASJN MODELING mirvrriHrinir>iii*irH-iranmmrmTmraiHimmi!-r<HiiaiiBmimiraiimBwmrii*rMaiiMi9]i 14 I MODELING FOR .ARJO DEDLSS-a Dam. TOR IBBKiATlON .... . 91 14 2 THE SI H BA5PJ MODELFwG «i; H7 J1 PW GrAfJWO" hi . 9J M-2 J #4 2 J ^prirtTdi Pr.'urT unWNM , . 1 fa R«fwrJwir /irjlim-i tf JMexstr Sufr iuum ....................................................... fa J* 2* — ....... fa IS. HECOM M E ND ATJQNS DN TRa FNI NG N EEDS........... ifll REFERENCES [] Water Works Design & Supervision Eourprise In Associate with kttrtiiatinHitai EonsirtMta Ud IttiuiDEriti Pn UdArjo-Dedessi Irrigation Project Meteorological and Hydrological Aspects May aw? LIST OF TABLES Table l i T^slL4 i Table * 2 Table 4 3- Table 4 4 Table 4 5 Table 5 i Table 5.2 Table 5 3 Tables* Table. 5.5 Table. 5 6 Table 5 7 Table 56 Tables? Table 5.10 Table 6 1 Table 6.2 Table 6 3 Tables* Table 6 5 Table 6 6 Table 6.7 Table a 1 Tables 2 Table? l TaBlE 9 2 Table 10 1 Table 10 2. Table 10 3 Table iO a Table 11 1 Table 12 1 Table 12 2 TaBlE 12 J Table 12* Table 12A Table 4-3 1 Table *32 Table 13 3 Table 14 1 Table 14.2. flREAK UP OF AjhBav BaSiN AREA 4 TaBlE Details CF METEORDlOGKTK. OlBSLta * T'CN STaTiQnS QCaT£c iN an. AROUND IHE l FKUECTaREa ......... ■■■ ......................... 26 TYPES OF CUMATic DATA AVAILABLE AT TnF va»Ou5 MFTEQRQlOG’Cal OBSERvaTiOa STATIONS ....... . Summary OF METFOftQtOGtCAL ChaRACTBRlSTlCS AT PROJECT ARE* SUMMARY OF ESTIMATED MEAN ETC QF ARJQ DEDESSA PROJECT AREA MAQNrnUDE DP ETo AT GWEN PO*-£iEED*a*CE PTOBABadTY LEVEL CROSS Correlation Matrix df Annual Rain* al . MeanMonThl* Rah#all ... . .. Parameter Estimates or wubull &stri&ution MONTHLY Rain*al„S CQ«tf SPCWING TD DIFFERENT Re_lABAtfTY LEVELS parameter Estimates Of half-momthl* RajmfAu. Half-Monthly Rainfall Magnitude t at Different Ae .jJulitv LEvElS HAi F-Month; y Ra'NFAu MAGNITUDES IN PERCENT &F THE MEAN CORRESPONDING TQ Different Reliability levels 27 28 2# Mi )7 3? 38 maximum annual 2*-hr Rajnfa^l Maximum RainFalu MaGniTuOES anC FREQUENCES Maximum Rainfalu Magnitudes for Higher Durations Availability of Streamf low Data in the Region M£An MONThlt FlQW (iN MM'7SEC,i Coefficient of varjaton of monthly Discharges Summary OF REGIONAL MCHTl*.* FlOW CHARACTERISTICS table Statistics of monthly fiqws at Arjd Deoessa dam sjte RfL'AftLITY LEVS I V5 Monthly StR£ amFlGwS AT DAM SlTE CHAftACTEHiSTiCS OF RanOOm INUWERS ^SEDFDR FlOW GenfRA^pQN estimated Flood Guanthjes Based on GEv OsTmauTioN Estimated FlOO© Ov*n* aEs Based oh LuG Distribution Table Cumulative v'Dljme cf Probable Maximum F^qqo De sign f loot Hydrograph Derated from Estimated Pmf RekA*IDNSHIPS between WATE R Discharge AhiC SEGMENT load Monthly total sediment load at the Reservoir Site ACCUMULATED Total. SEDIMENT Load at the Reservoir Site DiSTRIBuTbOn of SEDlME NY in THE ARJO DED£S$a RESERvChR water quAu:Tv re slats for sites oh the Oeqcssa r»ver Catchment Characteristics ....... SO ROTTED Design Flood at FRL CpfiflESPOKJiNG TO 1152 M Rou TED Design Koot at FRl GorrespokunG td 1555 m Rex. TED Design Flood at FRl Corresponding tq * JSGm Routed Design Floooat Coffer Dam of arjd Didessa Reservoir irrigation water Acquirements for various SC€nW»s Reservoir Characteristics at dead storage level . Storage Reservoir Characteristics and Reliabl .tv levels J'S 40 40 j! 4S 4-8 4® 4? 49 44 50 m sx sv ’0 'I -4 SiJ a1 b* gj as a? wj Total MDHTHL* REi FaSE (IRRiGat ion plus POWER | OPTIONS f DR wARIOuS FRl val jl s CONSIDERED .... _____ _ . , _____ _ 9- AAfriuAu ENFRGY GEhCRATiCJHSAT DE O?SSa Gam FQft THE V4SIOU5 OPTiQn$ y" J!T Water Works Design & Supervision Enterprise In Amciilt with LutereonttosoUJ CoDsuJluiUi ul Teebooenm Ptl LidAjjg Dedessa JitIjiaJdu Project MeieorotogicaJ and Hydrological Aspects MkX MW7 list of annexure AmEx A Al A2 A3 AA A5 M A? A9 AS Anne xb Bl 0? 03 94 @5 06 ST B« AmEX C Cl C2 C3 04 C5. C8 Anne*D DI D2 03 l> D5. D6 D7 DB D9 ANnFk E El E2 E3 e4 E5 Results obtained from the M£nEOftOLOGuc*.u Analvw Estimated Mean Temperature at ARzj DcdessaP^jCCt are.*, (in*C) Estimated Minimum Temperature at Arjg De dessa Project Area i,in Cj Estimated Maximum TcMPERaKiRE at ARX2 DEOESSA Project Area 1 INX) Estimated Relative. HuMiornr at Arjq OLDE SS* Project area (in perze nt i Estimated Mean Dajlt Sunshine Duration at Arjo De dessa Project area EsriMATED mean OaaE7oo* Aftjo Dedessa project are* Estimated Mean Monthly ETa of Arjd Dedessa ProjeCT Area Estimated MEat, MONTMlv RaAiFA^l at ARjO DEDESSa PROJECT AR£a Estimated Mean h**/-mohthlt Rainfal at the Project Area i.in mwhrj Results obtained from the fivdrologhza,. Ana*. *sis estimated monthly Flws *t arjq dedessaOm She Regional uomtul* C0Eff«mi of varlations |CV) Regional mOnIml* goEfkent OF SKEGNESS . . 16 Regional nkinthlt coefficient of correlations (Rj Standardized probability weighted moments ME.AN MQNThlt Total i.S JS0EnO€D and 6edj Se dime NT -OW1 ElEvEaTiOn-Area-Capacit* Relationships C* Ar jo &EOE 5Sa Reservoir Sample Simulation Re Sul ts of AhjO OEOESS* Resejivchr ... 103 IQ3 i'-tf 105 i De 1 q? iob i 09 1 .<} : 11 113 id tu 114 J4 fc 15 1D i !"» 115 Standards ...... —......................................... „...... ..................... ............................................121 Commonly USED values 0* RUNOFF COEFFICIENTS . . ^_... RuMXF COEFFICIENT for PERVKXIS SURFACES ST SELECTED rtYOUcxoGC SOIL SCS CuRvt NUMBE RS FDR VaRiOuS COKXThXS ' RjESERvc** Flood Standards ______ I2j Ratios of the basc 9*j€n5iOh£S5 hygrograph of the SCS GuOEtlNES FOR INTEftPfltTAFrONS OF WaTE R QUALITY FOR IRRIGATION i?l 121 122 i 25 126 METEQROUOGICM Bata................................................................................... ....................................... .. 127 □ETajlS of meteorological Obse RvaTiQn Statkjms TYPES Of Climatic Data avmlaBlE AT The various METEORQlCGiCaj. mean Monthly Rajm=all at BeO£l£ Station Mean Monthly Rain*al^ a: J=mma Station Mean Momtmi v Raiw al^ at Dedessa st atk> ------- . ... 12' 3 27 12a j2$ ,31 Mfan Temperature AT BfQfLESTA-xm .......... ................................ . bi Relative humid,nr at BFmi Static*, ia/% f J3 W«D S*tEO AT J'MUA Static*. J4 Sunshine Uuratiomat 6t DE lie Station hydrological Data list of selected hydrological obse rv a non Stations MEAa MQMThlv S TREAMFLDA at OEDtSSAN NEAR AR JO ST Al ■□*, Mean MQMTnlT S~REAm FLOW AT OtDESSAN rfAR DCmBi STATKMx Aniajaa Maximum F.ooqs MEASURED SEOIMF NT COMCEHTCATlOh AT GuMXRA GAuQfcG STATION ,j S j i It , 39 j, 4. Water Works Design & Supervision Enterprise In Ass eclair with InierconltitttLii CeutilluiU ud TecJnftcrita Pvi LidAru DEdes5*Jrrlff*tlOD Project Meteorological and Hydrological Aspects May LW LIST OF FIGURES Figure 4 1 MEam MOWThl* TEMPFRaTUHE at F«WRE 4 2' MEANMDMTHLV RElATrVF MumiDiTv *T 30 figure 4 3 meam monthly wino Speed at Figure 4 * mean monthly SumSmwe hours at Figure *.5 mean Mourn t etq at ar jq Deoe ssa project a«ea Figure 5i|a>' TREnC1 Analysis of Annua. Rainfall at jimmaStaticn Figure 5 Trend Analysis OF Annual RawFalk at BEDEl lE STaTKW Figure 5 1<C) Trend Analysis of Annual Rawau at Pewssa Static* Figure 5 2Jai Single Mase Curve of jimma Rainfall 30 31 42 42 45 4? Figure S.zjhj. Sacle mass Curve of Bedel_e Raw ................................................................................................ w Figure 5 ?<C) SinglC Mass Curve of Dedessa Rainfall Figure 5 3 Mean Mdnthlv Rainfall at arju Oedessa Prdjetct Area 44 45 Figure 12 T ElEVATiOn-AAea-CaPACITf Curves of ARjC DECCSSA Re SERVER K4 Figure i2 2 iw low and Outflow Flood hvdhographs at Ajr >c Dedessa Reservoir k- FiGuftE 12.3. IMFlCMw ANO O^'TFLOwr FlDOO HVDHOCAaPkS AT AP.JO DEDESSa RESERVOIR K5 Figure t 2 a Average hy daografh or maximum flows at Ar jo Of dessa Dam Site b& Figure 14 i Power Duration Curves Sfi ■----------------------------- ---------------- ------------------ --- ---------------- V Water Works Design & Supervision Enterprise Id Aseocbicc Hlh Intmoatinenul CodeuMmu ui Tecfraocrits Ptl Ltd.Arjo Dcdessa Imfxtion Prujrct Meteorological and Hydrological Aspects May 2007 1. INTRODUCTION 1.1 Th e Nile Ba sin Having a length of 6.625 km , the Nite River takes the rank of number one with respect to length, in the world It drams a total drainage area oi 2 96 M.Km4 with its annual total flow of aooul 64 0.t.3 As one could appreciate, lhe discnarge per Km4' is small when comparea lo oLher large rrvers of lhfl world From lhe Lake Victoria, to the Mediterranean Sea. Lhe river crosses very many different areas associated with different climate relief ano geology The main sources ol the river are the equatorial lake ptateau and lhe Ethiopian Highlands The three maior tributaries which emanate from the Ethiopian Highlands are. from south to the no<1h, the Bara Axabo. lhe Blue Nile, familiarly known as Abbay ana the Tekeze -Atbara System 1,2 Abbay Basin The AbD3y Basin is one Of the most important basims, Ih Ethiopia It accounts lor abaul 17 5% of Ethiopian land area 25% of its population ana 50% of its annua^ average Surface water resources in me Law Tana, it has the country s largest fresh water ia*e. covering an extent of 3000 km1 The Anbay nas an average annual run off of about 50 H m’ The overs of Abbay contribute on an average 62% of Nile nver flows in Aswan dam The climate of the Aooay Basrn is dominated by two features, namely, it s near equaional location ano in altitude range aetween 590 m amsi. to 4000 m amsi These influences resun in rich variety ol local climates rangmg rrom nobdesert like along (he Sudan OOrder to the temperate type on the high plateau with depiction of cold ir>1he rugn mouniams The Basin can generally tie d escribed as 5 emperate a t n igher elevation and tropical a t lower etevanons However due 10 the distinctive aspects of the highland climate, it <S perhaps better to describe it using the iocsi Climatic zones, that have oean established wdn elevation (and -esultant temperature^ as Controlling factors The Qoaa zone l«s teiow i860 meters and has annual temperature range from 2CcC to 2fi‘C The lAioma Oega zone lies between 1800 meters ano 240D maters ano has annual average temperature ranging horn 16’C to 20'1C The Uega zone, above 2400 meters has average annual temperalure ranging from If^C to 16’C The major portion of the population inhabit in me more climatically pieasant ano healthier upper two zones which leaves the lower Oolla zone sparsely populated Waler Works Design & Supervision Enterprise I la Associate with [ntereootln ratal Coasultiati and Tecimotrats |*vi Lid4rjo Dtdetift imeauDn Project MeieorgJcigicaJ and Hydrological Aspects May 200? There are mainly 3 rainy seasons The main one (kireml) lasts generally from June lo Septemoer. during which. the south was! winos bring rams from the Atlantic Ocean About 70% to even up to 90% ot the rainfall occurs during this season This season obviou&iy is associated wdh minimum levels of sunshine, low variations in aaily temperature and high relative humidity A dry season (Begaj lasts from October to January, during which clear skies are associated with maximum sunshine hours, high daily temperature variation and low relative humidity F malSy the m mor rainy season (Belgjiasls from February Io May. dunng which south east Winds tinng the small rains from lhe Indian Ocean The temperature range is very high in this season Tne precise timing and duration of these seasons vary cons-deratily depending upon location wilhm Aobay Basm. and to some lesser extent, yesr to year as well Generally speaking, the low aiidude depicts the patfern of "1 5 to even 12 5 hours of sunshine and temperature varying only for a small range from 3?C to 7“C through out the year The mean annual rainfall over the entire oasm COukt De reckoned at 1400 millimeters, where as the mean e vapoiranspiration is acout l 300 millimeter Broadly, based on the ramfall pattern, a different areas have been id&nlifieti by lhe earlier Master Plan study (Abbay River Basin Inlegrateo Master Plan Prated - 6CEOM in association with BRGM. 30 IS*, consulting Engineers - 1998). These are i) Soul hem area covering East ana West VVetlega, Jimma and llluoabor Zanes with relatively h»gn rainfall (1400*2200 millimeters, and a long wet season u) A central area covering most of Western Goiam and parts of neignoaring zones as weal characterized by reualivety high rainfall .1400 - 2200 milhrnelersj Bui there is a more pronounced seasonal pattern associated with snort wet ano longer dTy seasons III) An area covering most of me eastern pan pf me basin including North ano Soulh lWello Eastern oart of EasL Gajam ana South Gpnoar and much of Norin and North West Shewa region, excluding small proportion al mountain areas This area is characterized by relatively low rainfall (less man 1200 m<lkmet&r j distnbutea irt both the rainy seasons, depicting bimudality Water Works Design & Supervision Enterprise 2 In Auscuic with totircOBUncntal CnogaluaLs sod TtcbnocTwPj Ptl LidArj® Deaessa ImeaUfin Project MeteorDiogical and Hydrological Aspects May 2007 tvj The West ana North West millimeters falling area pred covering ominantly, North Gondar region. The rainfall rs about 1200 m the ma in rainy season ass ociated with tiagr ave rage rales of evapotranspi ration. Wrth res pect to the hydrographic scenario, the Basin is dom ina ted Dy Aooay R iver which nses *n the tenter of the catchment and develops its cours e in a clock wise spi nal 11 collects tributaries all along rts 992 km journey up to Sudan border As said earlier, the Abbay Basin catchment area of 199.812 km2 is encompassing the br&a& up as beiow As Gilgei Aboay the mam nver flows north (ram its source near Sekela into the w»de and shallow Lame Tana The tane also receives other tributaries from a catchment of 15.054 km" including tn butanes Megecn. Ribb andi Gumara. Shortly after leaving the lake the mar reaches the celebrated1 Tis Abbay fatlfi, thereafter flowing in a deep and rugged gorge on its way to Suoan Border The break-up of Abay oasm catchment area r$ available in Table i 1 1.3 The Deaessa Catchments The DOdessa River is the larges! tributary of the Aboay in terms ot the volume oi waler contribution to the lots- flow of AObay at [he Sudan boraer Draining nearly an area of 34.000 s quare kilo meters, t he D edessa nver originates m "he Mt.Venmo and Mt Wacne ranges, flowing in an easteny direction lor about 75 kilo meters, then turning rattier sharply to the north until it reaches the Aopay River The major tributaries of lhe Dedessa nver are the Wama. entering from lhe east, the Dabana from the west, and lhe Angar from the east. Dedessa Catchment vs sduaieo in lhe south-west pan of Abbay Basin The catch mem area at a gauging station near Arja town is 9.981 um-’ The climate of the Dedessa Catchment results from its location and elevation (1220 to 3012 meters } The catchment vs cnaractenzed by mountainous, highly rugged and dissected topography with deep slopes The iowest part of the catchment rs characterized by valley floor with flat to gentle scopes Must or the rainfall in the Dedessa Catchment is ooncentrated in the June to September period with virtual draught from Novemopr through February Annual totals, average from ies4 than 15C centimeters to more than 200 centimeters The Dedessa catchment, bes-des reflecting a marked rainfall increase with higher elevation, also receives heavier annual quantities than most of the catchments in the Abbay basin Examination or the rainfall records from this area shows that this is due to a longer (May through October i rainy season rather than heavier maximum monthly quantities Water Works Desl^ti £ Supervision Enterprise 3 [□ Isgoeiiit witt iDiBrEQnttnEnul Coosuliuits utt Technocrats Ptl LtdAr)o Dedessi IrrigaU&o Project Meteorological and KycWngiEai Aspects May 30U7 The mein annual flo^ of Odessa rtw at ArjO jtg-txjn 19 about 3.800 million ffl* having #3 majumum flow in August and September (52 percent of the annual] and mmunum (low hd February and March (J&ss than 1,5 percsnl or the annual) Further vwip desonplian □( the Climatic (actors ramfaU and hydrological parameters an made Jrt 1he ensuing respective sections of til repon Table I, j: Break up Of AOna y Basin Area System Tribulary Joining From Catchment Area (Km1) Lake Tana — 15.054 North Goiam Right side 14.389 Beshilo Left side 13.242 '/veieka -i 6.415 jemma ■ 15.782 South Gojam Rignt side 16 762 Muger Left side 8.188 Guder n 7,011 Fincha ■ 4 089 Deaessa 19.630 Angar ■ 7.901 Wonbera Rignt side 12.957 Dabus Left side 21.032 Beles Rignt side 14,200 Onder — 14.891 Ranad — 8.269 Total 199,812 Water Works Design i Sup etvlslon Enterprise Id AssbcImb mil tBUrEDnmLEntal CunstdlAnls auij TKbnctrtts Prt Ltd.JLrJ<i Osdtssj. |rTi£StUuq Fro] Kt Meteorological and Hydrological Aspects 2, REVIEW OF PREVIOUS STUDIES Ml? 2007 Because of rhe importance of ine Abbay, very many studies had been earned out m the past concerning lhe oasm Though, ihere Wfisl not any specific study lor the development of Dedessa suo basm exclusively, all lhe studies under taken, ptrlarrnng to Abbay or the country as a whole spoke q1 Dedessa development Hence though such a review has to be more exhaustive, it is necessary to undertake such a review defore attempting Dedessa sub basin development especiarly lhe aspects connected with hydrology in 1ms sectoral study Such a review is presented in me following suo paragraphs 2.1 Lahmayer 1962 Study This was mainly concerned With Gilgei An-Hay Scheme Although, 1: was HQl having adequate data base, the study provided interesting information about Gilgci Aooay and its tributaries, wtircr. couio be considered as a cars base for review ano up dating m the light of lhe raw data 2.2 Land and Water Resources of the Blue Nile Basin Ethiopia Th? study was jnoer tanen py rne unded States Department of lhe inienor Bureau erf Reclamation during 195S - 1964 This detailed study on Hand ano water resources development gl Lhe Agbay basm is worth mentioning imponaoL sludy Even ai 3 time, when there was a Irftle o< no data, very exhaustive analysis erf the available data nac been carried oui Loesiaofisn nydroiogicai studies Intact the pioneering works undertaken during that tune, has made Aosay basin m Ethiopia, to be u<oud of a possessing a good net work of hydrometric Stations lor making reliable estimates. The nycnoiogicai aspects nave been coverec in Appendix IP of the report. In 4 differed i sections of this Appendix, the various facets ol nyorpiggical analysis nave oeen pul forth as be*ow • Section 1; A general oascnptipn on ciimaie availability of waler, sedimentation rates and possible *rrhgalton requirements • Section II A presentation of the status of historical stream flow ano their elaborations. • Section III. A presentation on flow flows and the analysis attempted • Section IV A presemaljon on waler jse Water Works Design & Supervision Enterprise In Assonatf. HLh ifttertondoeniai Ctmsuttaais and Technocrats Pvt. jLrd.Jtrjfl-Gedessi lTTt£>tlflIl Project Meteorological and Hydrological Aspects May 20C7 In lhe Section I. on giving an account gf the synoptic anti climatic situations, the 22 stations with long care nave been analyzed tor precipitation and temperature The basm iSOLherm and precijutauon maps have been prepared based on above analysis The waler avaiUDHiiy aspects nave been also addressed m this Secnon I The samples analyzed al 5 stations indicated a igw sodium hazard; mgsl of them showed low to medium salimly hazard, some samples contained from none to a maximum d 0 2 ppm ol Boron, which was found to be (oieratxe by most sensitive crops The samples showing highest salinity w ere irom Mugger and Dinner With respect to sedimentation, ratings were established at 4 starions and based on extrapolation me sediment rate was computed at all the identified potential dam sues The panerr of sediment distribution in reservoirs expected alter 50 years of useful lite was adopted uniformly n a water o aiance t ype ol simuiation, 1 c* e stabhshing i ne success of e act of the identified projects in me seclFon 3 regions have oeen identified for development wnh respective crop projections, cropping calendar and trap water requirement The WfllfiT requirements varied from 7S2 millimeters rn Gdgel Abbay to 1375 millimeters tn Dmder area The section H has addressee the srream How development for loeanoos of ihe identified dam Sites by p 0SSib!& b«l sei or analysis available al the lime In [he study period 59 g augifiy stations were eslablishen. including 74 stations With automatic SLage records By the various analysis including graphical rainfall runoff correlations, tee Row senes were built up ai all dam tcrcauorte ana ai salient Jocanons The annual mean flows at Sudan border was estimates at 50 Bm’ For the Dadessa at Arjo. ihe correlated flows were established for 3 years r7911 tn tgi 7 ang I932j. The mean annual how estimate was 4332 32 Mm1 [eaten men, area 9436 Square kfo rnetsn) For ihe Daoana at Mum the mean annual flow was establisn&d al 1757.26 Mm3 (calcnmem area 3030 Square Kilometers} For tne Angar near Nekamte. the How estimate ai annua mean level was 2523 33 Mm3 iCatcnment area 4350 square xiiometersj Th Water WorXs Design & Supervision Enterprise la Assciciiit with tDlirtonUiwutal CODSuJlaots uil TtChoMrats Pvl Ll<LArjo Dedessi irri^iiOD Project Meteorological and Hydrological Aspects Hay 2007 For the proposed Deoessa dam, with a catchment area of 3360 square kilo meters, the How was estimated to be 1533 75 Mm1 Similady. for the cam sue at Dabana. with a catchment area ot 2654 kilo meters, the annual flow al mean level was estimated al 1515 63 Mm" For the Angar. 2 dam sues had been idanlifi&d. one at a location with a catchmenl area of 1780 square kilo meters | aG-2 D amj a nd a nolher a 11 ocation with a c atcnment a rea of 4 523 s quare k ilo meters iAG-6 Dam) The mean annual flows estimated respectively at these two locations were, 983.125 and 2251.26 MmJ The section ill, addresses toe causalive factors or floods >n Abbay The design raintoll for the basin was estimated cased on 6 representative station s data. These are presented below which are forming a data base worth for revLtw and up dating for adoplion 1 day design rainfall = 87 Midi meters 2 day design rainfall - 126 ' 5 day design rainfall = 185 * 10 aay design rainfall = 251 * 15 nay desigr rainfall = 321 * The design flood was estimated by phystoai approach using unit hydrograph, storm analysis and design t toed n ydrograpn convolution I or 21 dam sites F or t he others, f tooa i requency analysis based statistical return penod floods were estimatea For the Deaessa DD-2 reservoir toe PMF was computed as 5390 m3/sec with a base penoa of 99 hours. For the Dabana storage reservoir. The PMF estimate was al 4860 m^sec with a case penod of 91 hours. For the Angar-2 reservoir with a catcnmem area of 1780 square Kilometers the PMF ana the duration of toe nydrograpr were 3970 m’rsec and 80 hours respectively For the Angar-6 reservoir, the above respective figures were 6180 rr?/sec ano 111 hours. For toe Dedessa storage aam. tne 5. 10 25. 50 100, year floods were estimated io be 1700. i960 2100 2300 and 2400 m3i'sec respectively These formed a gora oata base tor review in me present study __________________________________________________________________________ 7 Water Works Design & Supervision Enterprise In Associate with InwreontbunUl Consultants and Technocrats Pit. LUAr)o Dtdou [mxiuou Project Meteorological and Hydrological Aspecis May 2007 The section FV as indicated m the beginning oeais with lhe water use studies The 19€0 water use status was reviewed along with such water uses in villages. Then, the run oil estimates have oeen aoopied considering the envisaged irngation and power developments ki respective simulation study Due io Oedessa dam USBR study, estimated a reduction o1 about 139 M ru in DedesM flows io me Aooay . On me whole, tors USSR siudy is a useful one for lhe Oasm as a whole, tnougn wi1h paucity of data, because u1 ns systematic treatment of hydrological and simulation aspects 2.3 Country wide Master Plan studies - EVDSA/WAPCOS (1908-90} These siudies were carried out during 19S0-9O for country wide water and tend resources development. covering all river basins. These were primarily desk studies for identifying potential imgakon and hydropower sites based on Country woe data ColtediDn and analysis, coupled with detailed map studies The study was addressing the Abbay basin also aiong with orher basins. The USSR studies were reviewed in detail far the Abbay basin. ana subsequently This study came out with modifications in me USER sites in some cases and proposed many other sites as well Though desk study the data ease availaDle to this study on nyorological and hyoro meteorological aspects were fairly adequate because of the earlier pioneering works by USER m esiabksning a good net work of such data observation stations In this study, the rainfall as well as run off aaia for the vicinity of the identilied projects were collected ana analyzed even though elaborate consistency checks were no1 uneer Lgnen The oala gaps idling and extrapolation of aala nave been done using statistical regression analysis using mostly orvanate linear as welt non tmear correlations in certain major dams, syntheiic Data generation by single sue multi season stochastic models as well nas been under taken With respect ip floods, the flood frequency anatysrs of the annual maximum flood senes has been cameo ou1 for the observation stahons, in the vicinity of all identified potential cam sites The EVi distribution with the methoa of maximum likelihood fitting has been followed in the above flood frequency analysis On deciding the approonate design cnfena for the inflow design flood for each loentifieo dam site, the flood peaks at the nearest gauging station nave been transferred to the dam sue by empirical formula. For deriving the shape of the complete design inflow hydrograph at the dam site the procedure as indicaied below nas been follower? ___________________________ __________________ . _________________ 4 Water Works Design 4 Supervision Enterprise In Asswtaw with Jntercobilnetjul Consultants ud Technocrats Pvl LidAJlo Dedesu Im^aba n Project Meteorological and Hydrological Aspects MiJ 3007 For the neares-l gauging station, lhe observed maxrmum flood hydrograph were iw.aled Far these a <e'ai*onship between lime ana Q/QP cartip were established 11 again sl Q/QP) where t represents time Q represents the discharge ai I and QP 15 the pea* discharge Using trus pattern of relationship the aam site hydrograph has been oeveiopea using the pea*, as estimated by flood frequency analysts. Simulation studies nave been systematical earned oul to judge me success of a scheme at criteria based rehaailiiy levels. Climatic data otner than raintatl have aiso been documented though without detailed processing or elaborations The sediment rates as Quoted by various previous studies of different easins have been acopled ana used in simulation studies, considering Ide expectancy of projecis as 50 years The data case on (he geomeiry of identified studies could be considered to be only approximate, as were oasea on purely topographic maps The hyjroiogica. ana hyarc metearotogicai data were also not put into rigorous analysis, which is called tor design of identified projects, riowever this study along with USBR study beck up gave a very good data base/ irweniory of an possible exploitable dam sites in Aboay oasm This EVDSA/WAPCO-S study has cameo out such exercise m all 1he other river basins of the country as welt The oams loenufied m me Dedessa sub basin by this study is the Arp Dedessa irrigation preyed. This proposal envisaged a dam. a chute spillway, an irrigation ouiiet with in take structure ano a canal taking off on the right Side The project envisaged irrigation over 135.000 hectares with 160% irrigation intensity The inflow in a 75% rehaDle year was estimated to oe 776 00 Mm3 The 10.000 year flood witn a peak of 090 cubit meters per second was getting moderated to an out flow hydrograph of peak of 642 cubic meters per second The Oeao storage was fixed as 93 Mm , an the basis of annual rate of around 1 9 Mn? 2.4 Study by BCEOM - in association with ISL and BRG 1999 The study entitled 'Aobay River Basin integrated development Master Plan Projecf has beer, cameo out with the following water resources onentec objectives 1 ________________________________________________________________________ y Water Works Design & Supervision Enterprise In Associate with Iniercontkmjtal Consultants sod Technocrats Pvt LU.Arj d Badass* ImraUao Project Meteorological and Hydrological Aspects Hit 2Wr • Preparation of the rwer basin development master pian thai will guide the development of ihe resources of tne Basin potentially with respect 10 occurrence, distribution, quality and quaniity of waler resources for ihe coming 30 1o 50 years • To prepare water allocation and utilisation plans under alternative development scenarios and io generate data information and knowledge that will contribute io ihe future water allocation negotiations with downstream countries The hydroiogicai and hydro meteorological siudies are more relevant for review in this section These aspects nave beer covered in Section ll, volume ill of Ihe Masler Plan Study report. The oasic climatic features and the climaloiogicai oata of the Abbay river basin are discussed first. The rainfall data procured by the study was for 173 stations, the data lengln vanea from 3 to 40 years, with associated monthly gaps. The dala for oiner climatic factors were availatre for 10B stations. Trie field verficanon oi these siations and equipments has also been under taken The dala is said io nave been subiected to analysis ano some errors connecter) wiln observations or processing were identified The study has perhaps noi attempted io improve me quality of sucn aaia on the plea ttiat it was outside the consonants capacity or responsibility As such, me data base after screening and omitting such erroneous data is staled io be good With respect to Hydrology in the pan 2of ihe BDOve volume III, the following aspects nave been covered systematically. * Sasic i-iydrograpmc Features • The Hydrometric nei work ■ Review of previous studies • Data collection ano Analysis * Sectoral mettiMpiogy bn the basic hydrographic aspects, a good wont of prepanng a map of Ihe basin has been presented dividing the basin tn to reasonably nomogeneous areas, named 'Basin Units representing each of the caichment or one tributary or of several minor ones wilh similar behaviors. With respect to the hydrometric net worn, it has been considered to oe adequate as ----------------------------------------------------------------------------------------------------- ------------------------------------- ---------- ! O Water Works Design & Supervision Enterprise In Assotiam wnh InicrtonUnsDUd Consultants *ad Technocrats Pvt Ltd.Arjo* Dtdr-ss a IrrigiLwii Project Meteorological and Hydrological Aspects May 2007 pe< WMO norms, taxing m to consideration 116 effective stations The list of staiion, therr locations. and drainage areas controlled have been well documented in T spies. appendices and maps The master plan nas found that the spatial distnbution of the stations is not even or equitable The pans of Besmlo, Weleka and Jemma were not adequacy represenied Based on visit to all accessible observation stations itie master plan could identify. * In many cases those stations which have been abandoned are nd worth reconstruction either they hao not been installed at oplimal locations or the catchment area controlled toy tnem was too smalt * The numbers of automatic water level recorders still operational at the study time were low ihough most of the stations had been equipped with such recorders at the time of tneir installations * tn many gauges stations the cables of bank operaied cable way were missing * On tne other hana most stall gauges were m good condition ana water level data was considered to oe quite reasonable. There upon recommendations nave oeer spell put to be executed as and when budget, equipmem and man power are made available in the first observation, it is fell that wnat is meant as optimum could have been indicated As tor as hydroioaicai net warns are concernea, optimality vanes Depending upon the purpose of the net work It could be a general purpose nel work or could be a specific purpose nei work it is not ctear that wnat is the master pian ascribed optimality Funner, since because a gauging station controts a small catcnment. it seems they have been ignored by Ine masier plan study Measurement of discharges have a multipurpose oriented utilities like ascertaining the sensitive ar non sensitive areas flood rate estimation or for a specific purpose including community based waler harvesting schemes etc Hence, the approach of ignoring stations with smai- catchments does not seem to pe nased on analysis of vivid concepts Subsequently, the Master Plan has made a very brief review of nydroiogicpi aspects of previous stuoies Again n is felt that a Masier Plan of the magnitude couid have reviewed in a _______ _ _ Water Works Design & Supervision Enterprise II In Associate with [niertontlneDial Consultants aad Teehner?LtdArfg-DwiKsa imeation Project Meteorological and Hydrological Aspects ■Tiare eiacoraie manner The review courtf have brought out each aspect oi hydrdiogiptil ano nytfra m&c&omiogicai a no simulation studies attempted by the earner studies Only such oelailec review would hare formed the natum to appreciate the Further studies taken up by rhe Master Plan. N6X1, tne data collection ana analysis part is discussed m the report The data sets processed were mean dany levels, discharge measurements and suspended sediment concentration Paia With respeci to data processing me major Study earned out seems to oe review and reestablishing rating curves The details on very many nydrcuogicaL analysis which should have been carneo out odone rinai use of he data in oasm simulation are not finding a piace in the hydrotogy venume (not explicitly eescii bed' With respect to rating curve analysis, detailed exploration ol the discharge dala of 121 stations have oeen made and eqvaiion erf the form Q = a (H-H f o have been fitted, wnicfi is common practice m Hydrology It is a good thing mat Master plan has used both analytical ano graphical methods m parallel m establishing such rating curves Pot ail the stations analyzed, a total of 25U equations have been arnv&o with gooc correlation coefficients of 0 50 ana above ir of the pairs at oata. The discharges have wen estimated using these equations. Then Master Plan stucy states thal on checxmg homogeneity, the monthly values wee extracted it would have been better to appreciate if the nomenclature erf Homogeneity with justifications nau been inchcsied in the repon. It .s aiso stated funner m me waster Plan that the discharges were compared with earlier studies ano the results dig not nave major vacations. Again it is leit that better appreciation could have been made if me concept of major variation had been spelt out. ------------------------------------------------ --------- -------------- - 12 Water Works Design & Supervision Enterprise In Associate with Intercontlctuiij Consultants and Tectinocrats Pvt. Ltd.Arjo D«de&sa Irrigation Prujfct Meteorological and Hydrological Aspects my joo? Subsequently, water Balance model ol the basin has tiean formulated Lakmg only representative s rations so a s t o m sue i ne m odd c wnprehensve iwlhodt p ver icadi ng T he selection criteria used for inenlificetiOfl and inclusion of hydttmeinc stations m me mooei seem to be appropriate. The mpur hydrological discharges were Bsiabiksned on daily time resolution level for the period of 33 years (1960-1992The gap................... ng techniques seem to have in bull subjective inferences. Wrin reaped to assessment ot water availability a map has been prepare^ ar a scale of 1 1D00 000 co estimate Ihs glo&a. water amiability to be applied in all pocentrai water resources oevetopmerit sues in Abbay bpsm. This map ceuid no of use just for a preliminary estimate of annual flows at pre-teasibihty tevci The water availability has been further estimated by retailed watar balance mwtei In tins. m the first runL tne present scenario nas been m built ano for IB net work stations, end water availability nas been estimated The salient findings of this run are as oeidw which era in order » The annu^L average volume [Towing across me border from Abbay River is 50.30 Bn? * Adoui S3% of tne average annual vgrume ai border is ripwing m 4 monihs I July - October), while the 4 months trom February 1o May ac count for le ss than 4 %o f tne mean annual flow • The average annual flow al the out iel from Tana rep resent s a DOui 7% o f the above annual flaws a1 border Floods:: The highest flood Hydrographs recorded ai each of the wate r baiance net w ork stations nave Deen put io analyses 1o establish lne relation between time and QiQm ratios Then Hood frequency analysis of the annual maximum discharges has been cameo out by Gumbei's EVl distribution to estimate the return psnoci flood peaks (It is noi clear whether the annuaL maximum observed peaks were convened in to instantaneous peaks) Further enatner reiationsmp connecting catchment size lo flood peak has oeen derived lor 2 groups of eaten meat sizes one for catchment groups having catchment area less than 10 Odd kfn1 ano another one 'or catehmenl sizes more than 10,000 km7 It has been concluded that tee formulae denied so can be used for pre-feasteiiity level studies only Master Plan has ___________________ _____ _____________ 13 Water Works Design & Supervision Enterprise Id AjsDEtate Tiih ] □lertohtbiBBial CrnisiiLtMts and Technocrats Pyl tut.Arjo Hun [nifidcD Project Meteorological and Hydrological Aspects Ml Ji 2W7 arlempied io i nk slope ai tfffwwiE catchmenls win flood discharge rates w*ncr- a s& d-d o r exhifcn any correlation ir has been opined m the Masier Plan mat ram'aii runoff crxrtul^i were nol applicable Ng data or study results pn flood side Will M di any use Lo me pTMenl project speci-c Study Ths flood slubies adopted by rne Master Plan m qhr be uselb to preliminary nbmales ie*e only Sodimetit iransppnation For 96 stations sediment rating cunts have bee- analyzed with available data, on me basis, of following iype pi relationships QL = 3 (H-Hb) ’ unking water level wnh How OS - ftQLn linking sediment discharge OS with tipuio discharge QL with a and p as parameters The KUI sedimentation Iran sported is acc&untM 3S Ute Sum <rt su spendeo sediment load ar.d bed load For bed ioau estimation. 3 drfferem options are indicated, with a toft or recommendation on Meyer Peter egualton However at the eixt of sediment deliberations Master Plan study hu +e<r mal a global estimate of bed looo transport for the whole Abbey basin gr for any of me large sub basins has no meaning; Hence the siudy nas tunner staled lhal at Master Plan level, considering the amount of bed road transport tefinriMy being small comparotr co suspended load ana considering the sue oi the Abbay basin it w?s not necessary to proceed with data coileclxm for evaluation oi bed load estimaiKm The above statement oi Master Plan is not able to be appreciated witnoul c<ucidBlicm Subsequenity, lhe Master Plan has prepared maps raoied to erosion The other studies oonnecled with water balance and water resources modeling seem rc be m order Software WATBAL has been used in lhe modeling to vanous scenarios T development after initial calibration to me present scenario Tnese have been done io* U Water Works Qwip & Supervision Enterprise tn Aisochtu wild LDtircoatlBetniL CntyutunU udTHbaMrais Pvt LtdAr]o-Dedftsti irrigation Prajsct Meteorological and HydrqlogCH-a! Aspects _ » present situation ■ Future situauon encompassing ci Scenario N“ 1 a Scenario N° 2 o Scenario N* 3 □ Scenario N 4 c (identified projects 1i (ioenlified projects 2 including Tana Beles} (idemifito projects in main stream) if all development) The results could be utilized For comparing tne results of specific sub basin oriented modeling studies, like tn& one under isken in the present sfoay 2,5 Study by Ministry of Water resources far Lower Dedessa (2001) Tins is a reconnaissance level study for the Lower Deoessa Medium hydro power project This gives a vivid analysis of the data and the Hydroiogicai features oi the Oedessa sun basin The oam ate controlling a eatenmant area of 1fl,200 square Kilo meters, has the following water resources poientia. according rp this stuoy Mean annual flow “7290 MmJ Annual Flow tn 75% exceedance year-6300 Mm1 Annual Flow m 30% exceedance year=6l 00 MmJ Annual Flow in 90% exceedance year=5230 MmJ Annual Flow in 95% exceedance year=46O0 tuTm] The following are the lrequency floods ecHmates 10 Year return penoo (food 20 Year rtf urn penod <!OOC i00 Year return penoo i'opn 1000 tear return period Tlood 10D00 Year return period flood =1977 cubic meter per second =2210 cubic mater per sewng -2735 cubic meter per second =3460 cubic meter per secono =4224 cubic meter per second A sedimem rate of SOOtons per square silo meter per year has been adapted This gives annual sediment load ol 9 1 million tons per year The SO year sediment volume of 329 MmJ hac been accounted for reservoir sizing ____ _____________________________ _ .______________________ __ J 5 Water Works Design & Supervision Enterprise In Assoclra kith iDtercaotlnttnjtl Gansu Hints icn) Ttctmocracs Put Ltd. ■Afjo Dedg&sa Imjtitlon Project Meteorological and Hydrological Aspects mij 2Q<r.' The siudy had analyzed me energy generation with a net head of 133 meters and wim toe assumption of regulation of 70% of lhe mean annual llow T he energ y that could be generated so, was estimated to De 1580 GWh per year, with an installed capacity of 299 MW. on adopting a plant factor of 0 6 This is very relevant to Dedessa sub basin and the present study The useful data were taken m to account 2.6 Utility of Earlier Studies All the earner sludies reviewed have some useful daia base Alt itie useful information (data o1 all tne above studies have been reviewed and utilized as per need and appropriateness}. However, lhe present study is specific sub basm (Dedessa) development study, and as such, systematic hydrological ano modeling studies are warranted wilh modern tools Df analysis. This sectoral report narrates these specific sludies Water Works Design & Supervision Enterprise In AssncLite with huercontlnBnlai Cuasuttants ind Technoc rats Pvt LuiATJo DedESEi tmgatlou Prnjstl Meteorological and Hydrological Aspects Hi; 2007 3. DATA BASE For the study towards itie development of 1he Defl&ssa sub basin, tne data on climate river flows and sedimentation oecome relevant with respect Io Hydrological Modeling and Vv alec Resources Planning 3.1 Climatological Data The climatological data like sunshine duration, relative humidity wind speeds temperalure in 1he resolution levels or monthly means of daily means, monthly mean of oaily maximum and monthly mean of daily minimum become very important parameters with respect to lhe proposed command area development These in association with command area rainfall form the basic inputs for the estimation of lhe crop water requirement exercise A vivid analysts follows on these important parameters in the section 4 of this report 3,2. Rainfall The rainfall requires cnticai analysis lor the dam site ano the upstream lor appreciating and developing floods either as a full hyorograpn or in the form ol flood peak rale, expected at different Exceedance probability ieveis return penods) The rainfall oata needs to oe analyzed m ns various forms, like maximum of observed 1 day/2 aay or 3 to 15 days vames or as a time senes of observeo annual maximum 1 day rainfall or as monthly / fonmgntly tolars as per analysis at different stages The analysis has io under take tne gambit of snort duration ramfall intensities as well, m connection wiih design ol drainages ano return period rainfall peaks lor the design of flood control worxs, m the downstream of the dam m ana m the vicinity of the proposed commano area. 3.3. River Discharge Likewise 1he river flows data time senes, preferably on monthly or fortnightly time resolution ieveis. forms the fore runner ior establishing water resources availability lor performing simulator whether as basic hisioncai time series or indirectly ihrougn synthetically generated time senes (mostly generated by a stochastic generation scheme}, where as the same flow oata nas to be analyzed in a dif'erent form as discharge (flow rates instead ol flow volumes} with resDect to flood analysis Water Works Design & Supervision Enterprise k Associate with Intercontinental Consultants and Technocrats Pvt LuL PAijo tadessa WftUwj N1F 2WJ 3.4. Sedment Data Ttie sedmenl data is obviously required co piar. the size of ine storages. for apponionmg itie active andindcuve storage spaces and for determining lite revised g eomietry of the storage after certain design life, (revised elevation - area capacdy relationship) as tins revised relation is used m ihe simulation modeling Toe water quality is another aspect which needs 10 □e addressed in Hydrological study along wdn low flaw analysis Tor mandatory downsream releases, aosety associaiee witn me concerns ci environmental and ecological aspects With suer, appreciation of the frame work of hydrological slmlies and modeling. the data base was established, as elaborately discussed in the intenm report. However in the Tallowing seclioas and m the annexufe enclosed with this report, the dais base an chrnaHKogy. Hydrology including sedimentalror floods are indicated All the data availaDle m a regional sense up to dace i2(XMj were Drought to analysis cesn and appropriately inciuaea Water Works Design & Supervlsloti Enterprise Id Associate with inurconunentil Consultants and Teebencrau Pvt. Ltd. ISArjo DcAbseb Irnjatteb Project Meteorological and Hydrological Aspects Miy axrt 4. ESTIMATION OF REFERENCE EVAPOTRANSPIRATION 4.1 Introduction Th* climate of the Ago Didessa catchmen t results ham ns location a nd el evation (i 300 to 3012 meters} The list of stations for observa tions of meteorological data along with iength of records and availability of data types is given in Table 4. 1 AH relev ant types of data nave b een record ed al Jtrruna (located very close to the neao of the Didessa catchment) stations since <953 Rainfall arw temperature have been ooserved al Didessa and Bedele Rainfall ana temperature nave been arso recorned al Demb> and Agara stations Climatic data for the project area such as temperature, relative humidily. sunshine hours, wind speed and rainfall have beer, collected ano reviewed Consistency tests, data rectification and other adjustments have Deen performed as necessary oata gaps have been filled using interpolation ano correlations methods as appropriate The FAO Penman-Monteith method is maintained as the soie standard method tor the computation of crop reference evapoteanspiration (ETO) from meteorological data. This section describes how [he monthly ETU is determined from temperature humidity, wind-speed and sunsnme hours data collected at Banir Oar station The ETe calculation nas beer earned out by means of a computer The FAO Penman-Momeith equation determines the evapotranspiration from the hypothetical grass reference surface ano provides a standard to which evapotranspiration lor various crops growing in the Aryo-Dedessa project command area can be related The melhoas for calculating evapotranspiration from meteorological aata require various dimeioHjgicai and physical parameters. Some of the data are measured directly in Banir Dar meteorological station. Other parameters are related to commonly measured data and can be derived wiih the nelp of a direct or empmcai relationship. This section discusses the source and computation of all oata required for the calculation of the reference evapotranspiration by means of the FAQ Penman-Monteith method 19 Water Works Design & Supervision Enterprise ' In Associate vlth IntencDnUnontal Consultants and Technocrats Pvt Ltd.Arjo Dedcssi lrrl£iUoa Project Metwrologi c a i an<J Hydro! ngical Asp ects The meieorol&gicai factors determining evapoiranspiration are weather parameters which provide energy for vaponzaifori and remove *aier vapour From the evaporating surface The principal weather parameters to consider are presented below. The data abiained from (he Beoeie, Cedessa and Jim ma stations are assumed directly applicable to lhe Aijo Dedessa irrigation Project wilhapplicauon 01 appropriate information transfer mechanisms 4.2 Meteorological Data 4.2.1 Meteorological Observation Stations Five meteorological observation stations ere locateo in ano around the Arjo-Dedessa irrigation Project area These meteorological data are obtained irgm the National Meteorological Senncss Agency (NMSA) Out of these Jimma is Class i station that include opservations ol rainfall, temperature relative humidily sunshine duration wind sjieec and evaporation Bettae and Dedessa are also Class 1 stations but do not include sunshine duration in addition Agars ano Demtn are Class 3 stations that include observations ot rgmlall and temperature. The longest record that covers 50 years of meteorological data is available ai Jimma station that Includes ramtail ana temperature data since 1952 Agaro ano Dembi stations are located withm the cachmenl area ot lh& proposed dam site Jimma station is located at approximately at 10 kmfrom me divide oi Oeaessa catchment Sedelle station is located close to the proposed irrigation tom mend area of the project Dedessa station is located further downstream gl lhe command area. The details like location, allituoe year of esibblisnmem aipng wild lfieir ciass are available rn Table 4 ' Meieonciogicai cars available at the five PoservauciTi stations locai&a in and a<ounu Itie project area fiava Deen collected The types Df meiearoiogical daiEa available at Ihese sEasions along wrtti lhe lenglh of data are given m Table 4.2. Jimma Airport meteorttogical ssaupn is taken to be the mosi reliable Class I sialron From which meieorologzcai information relevant 10 the project area has been derived The data trom Jimma station has been used lor noth the catchment study ang estimation or mereoroiogieai variables at lhe irrigaiion command area. The necessary adjustment for lhe differences in elevation has peer made in translernng the data. Meteorological information from Agara and Oempi stations __________________ _______________________________________ ■ 20 Water Works Design & Supervision Enterprise In Assnctate with tnurtantfoenial Cimsutunls and TMUnacrsisPn Lid.Arjo Dedessa [rnc*uon Project Mereorological and Hydrological Aspects Miy 2007 whicn ate totaled within the oam site catchment have Deen used for caccnmeni study m addition tp Jimma station. Similarly, meteorological data ol Bcdelle and Dedessa have oeen jsm in addition 10 the data obtained from Jimma station lor estimating rainfall and evapotranspiration al lhe proposed irrigation command In summary climatological I data obtained from Bedete. Deoessa and Jimma stations were found to De me most reliable and relevant for use in me analysis of rainfall lor Ine Ago Dedessa imgatinn project Bedeie is geographically the closesl station to rhe command area Oedcssa station and the command area are located 31 the same elevation (i e, both 1330 m asl) Jimma station (which is Class Ij nas the longest record of all me stations within the neighbourhood ol the command area so as to oe index station in extrapolating and interpolating missing and snort term of climatic data relevant to the Ago Dedessa catchment and command area 4.2.2 Air temperature In the projed farm area, lhe mean monthly temperature variations inrougnoui the year are minor, oemg 20 0°C in December to 25 4°C in March The mean monthly temperatures of lhe command area >s given in Taoie 4 3 ana graphically illustrated by Figure 4.1 Temperalure data nave oeen jsed in estimating evapotranspiration rates from reference crops Agmmeteorology rs concerned with lite air temperature near the level of the crop canopy In traditional ana moaerr automatic weather stations the air temperature is measured Inside shelters (Stevenson screens or ventilated radiation smeidsj placed in line with World Meteorological Organization (WMO) standards al 2 m above the ground Minimum and maximum tnermometers record the minimum and maximum air temperature over a 24-hour period Due Io the non-linearity of numidity data nequireo in the FAO Penman-Monteite equation, the vapour p ressure for a certain period should be computed as the mean between the vapour pressure ei the daily maximum and minimum air temperatures of that period The daily maximum air temperature (Tmil) ano daily minimum air temperature (Tw) are. resoectiveiy. (tie maximum and minimum air temperature observed dunng the 24-hour period The mean daily air temperature (T^^j rs only employed in the FAO Penman-Monteith equation co calculate the 21 Water Works Design & Supervision Enterprise In Associate with Intercontinental Consul tants and Technocrats Pvt Ltd.Aj)d- O-sdcsEi FTcjeci Meteonjlcigicalmd Hydrological Aspects May 2007 slope of the saiuration vapour pressure curves (4) estimating saiuraticn vapour pressure ■eTRancl aT/ (Steten-BDitzmann iaw) The so a.' radiation aosarneo by the BtmosphMe and me tieul emilied by trie earth increase me air lemperaiure. The senjibte neat ol rhe surrounding gm Iransfws energy 10 the crap and exerts as such a controlling influence on the rate af evapotranspiration In sunny warm weather the loss Of water by evapotranspiration <5 greater man m cloudy and cool weather 4.2.3 Air humidity Mean humility values vary between 56 63 percent tn March to 88 63 percent in September The mean monthly numidrty ol the command ares ts given m Table 4.S and grapmcalty Iluslrgted by Figure 4 2 Data pf humidity have been used m eslimalmg evapotranspiration rates from reference craps The reUbve humidity (RH) expresses the degree ol saturation of the an as a ratio of the actual te,) to the saturation (e‘(T>) vapour pressure ar the same temperature (Ti Reiaiive humidity it the rabp Between the amount ol water the amDiont air actually hekfe ano the amount it ctwkl n&d at the same temperalure. » is fl imensioniess ana is commonly given ass percentage Although ine actual vapour pressure might tw relatively constant throughout the day. trie relative humidity fluctuates between a maomum near sunrise ana a mmimum around early afternoon TTie trartefwn of the relative humidity is lhe resull cl the ted mat the saturation vapour pressure m aetermmec d> lhe air temperature As lhe tomporaLure cnanges ounng the day Lhe rpiaiive humidity also changes substantially While me energy supply from tee sun ana surrounding air is ine main dnwrvg force for the vaporization of water, the deference between the waler vapour pressure sl the evaparenspinng surface ano ine surrounding air is the determining factor for the vapour removal Well-watereo ft&kis in hot dry arid areas consume targe amounts pt water due to tee abundance of energy ana lhe desiccating power of the atmosphere, tn humid tropical regions, fflcuwrtnslandmg ine high energy input, trie fugn humidity of the air wtl reduce the evapotranspiration demand, in sucn an environment, lhe air is already ciose to saturation, so that »ss additional water can be stored ano hence the evapotranspiration rate is lower than in and regions. ------------------------------------------------------------ -------------------------------------------------------- 22 Water Works Design & Supervision Enterprise 1r Associate with btcreomhiKtal cnnsuitants and TtclmccrtLi^ Pvt Ltd.Arjo DedBssit Irrigation Projrct M et eornloglcal an tt Hydro! □ gLc a L Asp ecte 4.2.4 Wind $ pee fl My Mean wind speeo values vary between 0 48 meter per second in November to 1 Gfi meler per second m April The mean monthly wind speeds ol me command area are given m Table 4 3 and graphically illustrated Dy Figure 4 3 Average wmd speed recorded at Jimma station n meters per second (m/s) is taken as wind speed information relevant for me Ago-Dedessa command area as there is no reliable data at oiner climatic stations nearby. Time senes aspect of the wmd data rs not considered as it exhibits unacceptable erratic variation within the record penod. Using the mean values against the lime senes data has been tested for Sahir Dar station and resulted in equal result for monthly and annual evapoiranspriation estimates However the mean wind values produced an estimated coefficient of variation (CV) of 2 2% insreaa of 2.4% estimated from the time senes Wind is charactenzed by its direction and velocity. Wind direction reiers to the direction from wmcn the wmd is blowing. For the computation qI evapotranspiration, wind speed is the relevant vanaDie. Wind speed is measureo with anemometers- The anemometers commonly □sea in weather stations are composed ol cups or propellers which are turned by the torce oi the wine By counting ine number of revolutions over a given time penod. the average wind speed over the measunng pence is computed The process of vapour removal depends to a large extent on wind and air turtmtence which transfers targe quantities of air over the evaporating surface. When vaporizing water the air above the evaporating surface becomes gradually saturated with water vapour If this air is not continuously replaced wiLn doer air the driving force lor water vapour removal arid me evapotranspiration rate decreases. 4.2.5 Solar radiation Mean sunshine duralron is 8 3 hours in December and is reduced io 3.7 hours during July The mean monthly sunshine durations of the command area are giver, in Table 4 3 ana graphically illustrated by Figure 4 4 Data of sunshine hours nave been used in estimating evapotranspiration rates from reference crops i he relative sunsnme duration tn/N) is another ratio that expresses the cloudiness of me atmosphere. It is the ratio ol the actual duration ot sunshine, n, to the maximum possible --------------------------------------------------------------------------------------- -- -------------------- 23 Water Works Design & Supervision Enterprise la Associate wttn iQtercontinijDtat Ceng uitao ls and Teclu o c nits Pvl Ltd.Ar Jo Dadessi. Inigitioo PToj&tc Metearological and Hydrological Aspects Myjo(fiL_ duration of sunshine or daylrght hours N In the absence of any clouds, the actual duration of sunshine is equal 10 the daylight hours (n = N} and the ratio is one. while on cloudy days n and consequently ine ratio may oe zero. In the absence of a direct measuremeni of FL. the relative sunsnme duration, n/N. is often jsed to derive solar radiation from extraterrestrial radiation As with extraterrestrial radiation, the day length N depends on the position of the sun and is hence a function of latitude ano oate The evapotranspiration process is determined by the amount o! energy available to vaporize water Solar radiation is the largest energy source and is able to change large quantities of liquid water into water vapour The potential amount of radiation that can reach the evaporating surface is determined by its location and Sime ol the year Due to differences in the position ol the sun. the potential radiavon differs al vanous latitudes and in different seasons. The actual solar radiation reaching the evaporating surface depends on the turtudity of the atmosphere and (he presence of aouds whicn reflect ana absorb ma^or parts of the radiation When assessing the effect or solar radiation on evapotranspiration, one shoe la also bear in mind that not all available energy is used to vaponze water Part of the soiar energy is used to heat up the atmosphere ana tne soil prdlile 4.3 Pen mart-Monteith Equation From the anginal Penman-Montetth equation and the equations of (he aerodynamic ana canopy resistance the FAO Penman-Monteilh equation can be expressed as follows ETd = gjQ£Al£. r 27311 (2 1) i + T(I + D.34 uj where ETO = reference evapotranspiration [mm Oay ] 1 R = net radiation at the crop surface [MJ m' n 2 da/1], D 1 G = sod heat flux density [MJ m'3 day'']. T = air temperature at 2 m ne»ght [ C], u 2 = wino speed ai 2 m height [m s' ], e & = saturation vapour pressure [kPa], e = actual vapour pressure [kPa] = e, RH^. Water Works Design & Supervision Enterprise In Associate wiut iBtarcAnUnenta] Consultants and Technocrats Hl Ltn. a 24Arjfl DfldBEss IrrigaLluD Project Meteorological and Hydrological Aspects and 6^' e» = saturation vapour pressure deficit (kPa|. i - slope vapour pressure curve [kPa ‘C‘’|. 7 = psychrometric constant (kPa C’’| RH = relative humidity divided by WO R.’ = Rra " RrJ RPi = 0 7T Rs Rs = (025 + 0 50 n/M)R, RrJ = rT/(0 34-0 14 e.0 4 5)^ 135 Rs’Ro-0 R„ =(0 75*2 ( Altitude X1 D0000| R» (2 2) (2.3) (2 4) (2 5) (2 B) The calculation procedure consisls ot the following slaps 1 Derivation ol some climatic parameters from i he o aily maximurn (Tm) and minimum (T „) air temperature, altituoe (zj ano mean wind speed (uj). r 2 Calculation of tne vapour pressure deficit (e,. * e ). The saturation vapour pressure (e,j A is derived from T^,, ana T™^ while the actual vapour pressure (e^j can oe derived irom the dewpoint temperature (T^j. from maximum (Rb^j and minimum fRb-^.i relative humidity from the maximum (RH™*,). or Irom mean relative humidity (RH „J. m 3 Determination of the net radiation (R„j as the difference between the nei shortwave radiation (RnJ and the net longwave radiation (R™). tn the calculation sheet, the effect of ml hesi flux (G> is ignored tor oaily calculations as tne magnitude of the flux in this caw is reratively small The net radiation, expressed in MJ m'2 day'1, is converted io mm/day i equivalent evaporation) in the FaO Penman-Monteilh equation by using D 40B as tne conversion factor wiLhin me equation 4. ET0 is obtained Oy combining the results of the previous sieps. The following values were selected from FAG 1990 (Crop Evapolranspiralibn - Guidelines ior computing crap water requirements - FAC Imgation and drainage paper 56) □ Psychometnc constant (y) for differeni allitudes (z), .___________________________________ ________ 25 Water Works Design & Supervision Enterprise Id Associate with IntercontliifiiLal Consultants and Technocrats Pn Ltd.Arjo-Dedess* IhIeiUad Project Meteorological and Hydrological Aspectg__________________________________ — □ Slope of vapour pressure curve i.^) for different temperatures (T). o Saturation vapour pressure [(e'(T)l for different temperatures (T), c Daly extraterrestrial radiation (R>) for different latitudes. o Mean maximum possible daylight hours (N) for different latitudes, □ oT/ uStelan-BoiLzmann Sawj ai different temperatures (T) The estimated mean daily and monthly reference crop evapotranspiration magnitudes (in mm) from 1991 to 2004. oased on Penman-Monuenn Equation, are presented by Tames 4.3 arm 4 4. respectively anc graphically illustrated by Figure 4 5 The results at the meteorological analysis including the rainfail are provided in the annexlure A Tanle 4.1 Tabic Mwte o* Meiwwogical Observation Slations located in and around the proiec? area S.No Station Name Latitude North Longitude East Altitude (m| Period n&g, Um D’fl Min. 1 Agaro 07 51 36 36 t700 19SO-20O4 2 Bedeile 08 27 36 20 2005 1967-2004 3 Dedessa 09 33 36 06 1300 1971*2004 4 Demo. 08 04 36 37 i960 1954-2004 5 Ji mm a. 07 40 36 50 1725 1952-2004 Tien? 4.2- Types of Clmatc Data available ai the various Meteorological Observation Stalrons NO Siauon name Yrs RF Tm RH ws StJ 1 hr 1 da Relay i Dioessa 30 X X X X 2 Bedeie 26 X X X X ¥ 3 Dembi 20 X X 4 Agaro 21 X X 5 Jimma 50 X X X X X XXX 1 Yr$ refer tc rairfal! senes cu» 1 1 3 3 RF monthly rainfall Tm average Temperature SO sunshine duration 1 hr RH relative humidity maximum 1-hour rainfall W5 wino space 1 day maximum i .-oay rainfall Rday number 01 rain days 2b Water Works Design & Supervision Enterprise In Aswclate with Inwrconnneetal Consuiujnts and Technocrats Ptl LuiArjo Dodess* Irrl^iUun Project Meteorological and Hydro logical Aspects Table 4.3: Summary of Meteordoflitsi CtvaracterulKS at Project Area Jan Feb March April May June July Aug Sept Monthly Mean Temperature m oC Serene 21.9 23.15 25 4 25.05 24.03 22 09 21 32 21.19 21 83 cv 0 048 0.044 0 036 0.065 0071 0 029 0 028 0.031 0.027 Skew 0.071 -0 58 0.067 -3 628 -3.23 0117 0275 0 007 0.93 May 2007 Oct Nov Dec Mm Max 19.5 20 44 23 63 16 26 15.89 20.96 19.99 19 88 21.06 24 6 24 9 27 37 27 72 26 19 23 41 22 72 2234 23 2 22 35 22144 19 99 0.036 0 0544 0 066 0.353 -0 118 -0 02 20 19 19.081 16 92 24.25 25.051 22.68 R«nUjfiive Humidity (*/•) Average 64 77 58.97 56.63 67 97 75.72 61 07 87 46 88.52 86 63 84.55 79 366 72 44 CV 0.099 0 127 0.084 0 073 0 053 0.047 0061 0.048 0.03 0 053 0 0705 0 089 SrCw ■0 27 ■0?7 -0.37 0474 0 2 -0.87 ■2 92 '2 □ 249 019 0 287 -0 13 Min 51.5 43 2 4509 57 42 65.23 65 8 61.77 72.23 8249 74 24 67.667 55 37 Max 77.3 71 68 64 08 62.17 86.18 90.3 98.1 97 53 95 67 94.73 93 187 85 13 kVino' Speed 082 0.8 1.0 1.06 1 04 0.86 062 0.51 05 0 51 0 48 0 51 Suns/woe Hours 'hrsvoay) Average 8.155 7.638 7 452 7.28? 7.624 6 061 3 703 4 059 6 164 7.855 8.3245 8.306 CV 0 125 0.166 0.145 0165 0157 0 189 0 243 0.23 0 22 C 139 0.2139 0 104 Skew -047 -0.36 -0.27 -1.12 0.141 -0.36 0.248 -0 42 -0.27 0.138 3 525 0.971 Min 6.05 4 905 4 592 3.304 5 428 3.364 2.277 16 2.622 5 778 01121 5 634 Max 10 9919 9.744 9 44 10 15 8 12 5 445 6.2 9 12 10 08 10 201 11 02 Water Works Design & Supervision Enterprise In Associate with InterconUntiiial Consultants and Technocrats Prt LuLArjiyDeifes-si Irrigation Project Meteorological and fiydro logical Aspects Table 4.4. Summary of Esllnulted Mean Eld Of Afjo Dedessa Project Area May 2007 Jin Feb March April May June July Aug Sept act Ngw Dec Daily: Estimated ETa \mm/day) Average 3.7 4.11 4.62 4.51 4 33 3 58 2 96 3 11 3.81 4 03 3 79 3 44 CV 0.05 0.06 0.05 0.07 0 06 0.08 0 08 0.08 0.09 0 06 0 12 0.05 Skew <l 47 -0.77 4) -0.05 -0.55 -019 0 33 -0 51 -D 18 -0.27 -3 11 0 88 Mir 3.23 336 3.90 344 3 35 2.97 2.58 2.44 2 88 3.5 1.95 3 11 Max 4.03 4.49 5.24 5 13 5.06 4 15 3 46 3 59 4 49 4 4? 4.24 3.96 Wonf/?ly Esfrmaitfd ETo mm/rnonth Average 115 115 143 136 134 107 91.8 96 5 114 125 114 107 C\/ 0 05 0.00 0 05 0 07 O-QS 0 08 0 08 0 08 0 09 0 06 0 12 0 05 Skew -0.47 -0.77 -O -0.95 -0.65 -0 19 a.33 -0.51 -0 18 -0 27 -3.11 0 88 Min 100 94 6 124 103 104 09 80 75 7 86 5 W9 58 6 96.4 Max 125 125 162 164 15? 125 107 in 135 139 127 123 Estimated Eto (mm/day) i form avers-je values of data 1 Average 3.69 4.06 4.66 4lfl 4 2B 3.57 2.95 3 10 3 75 4.00 3 79 344 Estimated" Eto (/nm/monitfy form ivtrage values of data/ Average 114 114 142 134 133 107 92 96 113 124 114 107 Mote? ^oui annua E7<j = 1397 nvr 2S Water Works Design & Supervision Enterprise In Ilssdcuhc with bit€ rcuntlistn LaJ Consultants and Tfithn oorats Pvt Ltd.JkTjflMessi IlTtJlUon Project Hetearoicgl cal and Hydrological AspscU T»Wt 4,5; Magnrlude or £ To at gwgfl non .exwnanre ?rQtwUiMy Javel PY&tMJitex Jin Fit) Mar April May Jun* July Av0 S*P< Oei Nov Oat 55 3 72 4 14 4.05 4.56 4.37 3 61 2 99 3.14 3 05 4 06 384 3.40 60 3 75 4 16 4 63 4.60 4.42 365 3 02 3.ta 3 89 409 3.90 3 49 G5 3 77 4.21 4 71 4 64 447 3 66 3.05 3.21 194 4 12 396 3 51 70 3JW 4.25 4 75 4 69 4.52 3 72 3.09 3.24 399 4 15 4 02 3 53 75 3-63 4.29 479 4 74 4.57 3 77 3 12 3 28 4 04 4 19 4.09 3.56 £0 3 06 4.33 4 33 4.00 4.63 3.01 3 16 3 32 4.09 4.23 4 16 3.59 35 3 90 4.36 4 98 466 4 70 3.87 3 21 337 4 16 4 28 4.25 3.63 90 3.95 4.45 4.94 4 95 479 3.93 3.27 3.44 4.24 434 4.35 3 67 95 4.02 4 54 5 03 5 07 4 93 4.04 3 35 3.53 4 36 4 43 4 51 3.74 A*-g 370 471 4.62 451 4.33 3.58 2.96 311 3.31 4.03 379 344 May 2007 fmm/mouTffy FWBy Ja n F«n Mar Appill May JynaJuly Aug Sapt oct Nor D-ec Annul! 55 115 116 144 137 136 ioe 93 97 4 116 126 115 107 1405 00 116 117 145 138 137 109 94 98 4 117 127 117 108 1412 65 117 110 145 139 ’30 111 95 99.5 118 128 119 109 1420 70 110 119 147 141 140 112 96 10T 120 129 121 110 1423 75 119 120 148 142 14? 113 97 102 121 130 123 110 1436 B0 120 121 150 144 144 114 98 103 123 13T 125 111 1446 85 121 T23 151 146 146 1 is 99 105 125 133 127 112 1457 90 T22 125 153 148 149 116 101 107 127 135 131 ^14 1471 95 125 127 156 152 153 121 104 109 131 13? 135 116 1492 Avg 115 115 143 135 134 107 92 96.5 114 125 H4 107 1397 hu.ifu Growrtft factor (Xp) FraUMy Jl-n Fab Mar April May Juna July Aug Sapi □ci Nov free Arrnp^l w 55 1.01 TOT 1.01 101 1 01 1.01 1.01 1 01 1.01 i-Oi l 01 1 01 1.005 60 1.01 1 02 1.01 1.02 1 02 1.02 102 1 02 1 02 l 02 1 031 01 1.01 «5 1 02 -.02 1 02 1.03 103 1.03 1 03 1 03 1 03 1.02 T 04 1.02 1 016 70 1.03 T 03 103 1.04 1 04 1.04 1.04 1 04 1 05 1.03 1 06 1 03 1.022 75 l 04 1 04 1 (U 105 1 05 1 05 1.05 too 1 06 1 04 1 08 1 04 1.028 60 1 34 105 i 05 1 06 1 07 1.07 1.07 1 07 1.07 1 05 1 1 104 1.035 85 1.05 1 07 1.06 1 08 1 09 1.00 1 08 1 08 1 09 1.06 1 12 t 05 1.043 « 1 07 1 08 1.07 1 1 T 11 1 1 1 1 1 1 1 11 1.08 1 15 1.07 1 053 95 1 09 t.1 l 09 1 12 1 14 1.13 1.13 1 13 1 14 1 1 1 191 09 1.068 11l1111111111 29 Water Works Design & Supervision Enterprise in Associate with intfrre-on.Ll_nen.L3i Coosuitiqis and Tectumnts Pit lieAr>D*dem LrrHanoc Project Meteorological and Hydrological Aspect^ Figine 41 Meih Monthly T«mpM*tur» at Arjo Dcdessj* Project Area Itiy 3007 Figure 4.2: Main Monthly Relative Humidity at Arjo Dedessa Project Area Figure 4.3: Mean Monthly Wind Speed at Arjo Dideaa Project Area Figure 4.4. Mean Monthly Sunsnine Hours Arjo Dedess a Project Area Water Works Design & Supervision Enterprise !□ Associate with Interttnclnwu] Consultants and Tec. b tide rats Pit LilETo imm] VJ o Dfldtfcu Irrigation Frajtci Meteorological and Hydrological Aspects Mi} E0P7 F<»ure 4.5: Mean Monthly ETa it Arjo Didnss Project Area U Water Works Design & Supervision Enterprise In Associate wio Intercontinental Consultants and Technocrats Pn Ltd.Arjn De Jess a IntgadoD Project Meteorological and Hydrological Aspects Miy 2007 5. RAINFALL ANALYSIS 5x1 Introduction The rainfall data attained from Bed ele. De dessa an d Jimma stati ons were founu to be the mosi rehaole and relevant for use m me analys is of ramlall for the Arp Dedess a irriga tion project Beoele is geographically me closest station to me command area. Dedessa station ano Ine c Dmmand a res are located a 11 he same elevation ( l e. o otn 1 330 m a si) Jimma station (whicn is Class I) has the longest record of all the stations within the neighbourhood qI the command area so as to tie index station m extrapolating 3nd interpolating missing and shortage ol rainfall data relevant 10 the Arjo Dedessa catchment and command area The ramlall in me Arjo Diflessa Catchment as welt as in its surrounding i$ uni-modal type Mosi ol ihe rainfall is concentrated in the May to September covering with virtual drought from November tnrbugn March The five wettesl months cover 63 percent of the total annual ramfall The dry season, being from November to February (four months) has a total rainfall of about 7% ol ihe mean annual rainfall The mean monthly rainfall for stations m the project area is given in Tabic S 1 and their pattern is graphically illusiratea m Figure 5 3 The length of rainfall data collected from Jimma is relatively more retiaoie compared to the oata set collected from other stations because of its long record length and shorter time interval of ooservation. Didessa ana Bedeie statrons also provide more relevant rainfall data IhaT cap be adopted for the command area since Bedele is dose to Ihe projeci area and Diaessa station is located within the same dimatic zone as that ol the project area 5.2 Rainfall Internal and External Consistency Though a good oata base has oeen established lor rainfall. considering the data of the ihree stations namely Dedessa, Jimma ana Sedeie, it is customary ir. Hyoro-meteoroiogical studies to firm up the consistency wilh statistical analysis. The trend in the annual rainfall pattern is a relevant aspect with respeci to me behavior of the rainfall and to compare sucn Dehavior wilh those ol other relevant stations involved in the study with a view 1o firm up external consistency. Accordingly, a 3 year moving average anafysis ________________ ___ ______________________________________________ 32 Water works Design & Supervision Enterprise Tn Associate with [nierconUticiiEal Consultants and Technocrats Pvt Lid.Arjo Dtdes-sa Irrigation Project Meieorologi cal and Hy tiro logic al Asp acts was taxen up for each of the 3 stations The results are shown in the figures 5 1 ( a|. (b„■ arg . These show similar trends Similarly an analysis wiUi respect IO the cross correlation structure among the 3 Matrons was earned oui The cross correlation main* depots the fol owing status 4 Table 5.2} al annual tune resolution level, wmeh is not abnormal Then the single mass curve analysis was taken up for each Bf these 3 slatons (Figures 6 2 (a), (b) and (c) These also do nor indicate any abnormality to reject this data set As such, these ramfali dais were used m Hs different forms rcr various speeffums of me analysis 53 Estimation of Rainfall Reliability Level Using ine rainfall ana irrigation waler available for the command area requires tne magnitude and reliability level of rainfall corresponding Ic various rainfall time mlervals. Annual, monthly and half monthly intervals are chosen durations for the Arjo-Dedessa irrigation prgjeci Ramfati reliability level and magnitude can De analyzed by making use of theoretical distributions in this study Ine Extreme yaiue Type III (minimum) distribution was utilized The dislnbulian is aiso known as (he Weibull distribution or aS GumbEi S Limited distnbution of ltie Smallest Value Naturally rainfalls are ocuna by zero or olher higher values on ihe itfi The W«buB (c* EV3j distnbution can be expressed as (5.1) when Xp =E*(D-F>i-lri(1-p)rJl Xp = magmtuae ol rainfall corresponding to probability level of p The moment estimates of Ihe parameters E (the lower limit), U ana a (te., E, and A) «n pe obtained from the following equation U = Xm * Cv.Xm Y(a) E = \j - Cv.Xm.Z(aj Water Works Design & Supervision Enterprise In Aswclite with intBrccnUMntxl Cansuliahts isd Technocrats hn. ted. (5 2) t53lAijo &flijeisj irrtfitlwi hrojeci Meteorological and Hydrological Aspects where Xm = mean value, Cv = coefficient of ^nation = starward devianan di video by the mean Y(a) = {2-Csy6 Z(a) = [8+(3-Cs)>9 and A = 3/(1 +Cs) Cs - snew coetticieni calculated from data The estimated moninly ano half-monthly parameters of Weibull Distribution are given m Tabe 5 3 arid 5 5. respectively The following algorithm were used in the derivation ol annual, monlhly. and half-month 55 to 95 percent reliability levels. 1. Averages, standard deviations, standard Deviation, skew coefficient of annual, monthly ano half-monthly averages were calculated 2. Weibulf Distribution parameters (namely Id. E and A) corresponding io annual, monthly ano naif-monthly rainfalls were calculated from the statistics 3 Magnitudes of rainfalls corresponding to 55 to 95 percent reliability levels were estimated The results so obtained are given in Tapies 5 4 and 5.6 for monthly and half-monthly time intervals, respectively The naff monthly ramtafl magnitudes as a percentage or mean, corresponding io various reliability levers are shown in Table 5 7 5.4 Estimation of Maximum Rainfall Frequencies For imemal drams ano smaller control works, the need for various return period rainfall ano with different durations were 1ound tc be necessary In general, maximum rainfall magnitudes ___________________________ _____________________________________________________ 34 Water Works Design^Supervision Enterprise fn Associate with Intercontinental Consultants and TcchJldcmls Pvt ltdArjo Dedsasa Irrigation PrDjtcl Meteorological arnJ Hydrological Aspects Hay 2t»r of intensity corresponding to various relum periods [or probability levels) can tut est-matec by applying ‘he lollowing form It = Im [1+ CV.K(TH (54> where It = rainiari intensity corresponding io return per-od at T years (mmj, lm = rnean of annual maximum intensity of ramfail (mm'hr). CV = coefficient of variation of annual intensity of rainfall KfT) = frequency factor For Extreme Value Type i (ocGumoef) Distrrbutioc, K(T) = *0 779 (0.577 + ln.ln[T/{(T -1}]) The maximum annual 24hr rainfall service is given in Tattle 5.8. (5.5) The results of lhe maximum 24-hr and 1’hr rainfall frequencies are presented in Table 5 9 The 1-nr ramlall intensities were estimated by 1he formula derived for Ethiopia expressed as = 1^40.523 + O.lSln D; (3,6) where l P - maximum ramlall intensity correspond mg to curation D (mm/hr), in - natural logarithm D = duration of lh (hr), In = maximum rainfall intensity corresponding to duration 24 hours (mm/hrl . tie amfail rnagnrtuoes for higher durations, 2 aays & 3 oays have also been analysed using lhe EVI frequency distribution, The results for vanous return periods are shown m Table 5 10 Mora details ol me analysis are available ir me annexure A "Results obtained from meleorologrcai Analysis' Water Works Design & Supervision Enterprise In Associate with InterconUnenial Consultants and Technocrats Pvt. Ltd..ATJ 0 Dedcfiii ItTifttlUI] Project Meteor&log1ca]mi£ If y rl rc i i»I cal Aspects The annual rainfall available at differenl years are given below suy SM? hear year = 1453 mm 75 % year = 114S mm 80 % year = 1090 mm 95 % year ■ 653 mm Table 5.1: Mean Monlbty Rainfall Dticripttafi Jan Fe& March A pril May June July Aufl Sep 0.1 Nov Dec Tfllal □idessa 3 6 26 49 158 274 312 277 209 104 28 8 1454 Oedele 18 23 65 105 239 291 310 303 302 156 41 12 1864 Dembi 25 44 101 128 223 303 307 367 290 145 52 29 2013 Agaro 24 36 SB 93 149 232 234 231 174 127 54 30 1471 Jimma 33 49 88 133 172 219 208 210 182 103 68 36 1502 Table 5.2: Cross Correlation Matrix of Annual Rainfall —--------------------——r-— Dedessa Jimma B edele Dedes&a 1 0)1 0 24 Jimma 1 0 48 Bedeie 1 Table 5.3: Parameter Estimate* of Weibuil D istribution Jin Feb Mir April May June July Aug Sept Oct Nov Dec Annual y(a) 0 5 06 06 04 0.5 05 08 04 04 05 11 08 0.4 i(a| 02 0.2 02 0.3 0.2 0.3 0 1 0.3 03 0.2 -01 0 1 0-3 □ 24 2 1 22 3.6 2.4 2.9 1.3 37 34 24 09 13 3,2 E 183 21 9 61 2 81.5 201.1 267 3 252 9 257 7 245.0 1 31 0 30 0 13.9 1541 ■12.9-15 0-17 4 -55.3 -9 6 73 154 l 35 9 60 9 -29 9 3 8 -4 4 575 D - Xm *Cv'Xm -/fa, E = U - Cv*Xnj-jfa; X = E + n>E; Y-frif?- VT)*f f/ej •6 Water Works Design & Supervision Enterprise In Associate with InureDntla«nEa) CoosultHnis end Tefhnnmts hi. LidAr jo Detfetta imuttlon Project Meteoroioffica] and Hydrological Aspects Table 5* Monthly Rainfall* Corresponding to Difffirflhl RtliabUity teve Is Reliability LeveiJ an Feb Mar April May June July Aug Sep! Oct Now Doc Annuat (%) 55 10 B 12.2 40 9 58 1 150 213 219 221 212 91 65 18.6 7.58 1353 6C 8 84 9 79 35 8 51.7 13? 198 211 210 203 81 66 16.36 12 1304 65 6 92 7.4 30 8 45.3 124 184 204 200 194 71 76 14 24 74 1253 70 5 5 03 25.8 38 6 ill 169 197 190 184 61 82 122343 1202 75 3 04263207 31.5 97 9 154 190 178 174 51 68 10.42 16 1148 80 0 990 16155 23 8 84 2 138 183 166 164 41 13883092 1090 85 0 0 9 97 15.2 69 4 120 177 152 152 29 86 7 36 0 1025 90 0 0 3 87 4 84 529 997 170 135 138 1729602 0 951 95 0000 32 7 73.7 163 113 119 1 974 4 82 0 853 Avg 15.31 SA 53.6 69.5 180 8 2*3-0 Z45-9 238.3 229 6115.531.412.7 1453 Table 5.5: Parameter Estimates of Hal ('Monthly Rainfall JWoofh Parameters of Weibuii distribution 1fa XW U — - - H 1.1 0.8 0.1 1.5 8.6 -43 1.2 0.9 0.0 1.1 8.1 -2-6 2.1 12 -0.1 0.9 77 -4{J 2.2 08 01 1.5 11 0 -6 1 J.1 0.6 0.2 16 24 3 -14,8 32 06 0.2 20 37.7 -11 7 4.1 06 02 19 26 5 ■135 4.2 OS G.2 24 54 5 25 6 5.1 06 02 19 87.6 -11 2 52 06 0.2 20 112.7 75 6.1 05 0.3 2.6 134.3 •19 8 62 05 02 2.5 135 10 4 7.1 07 0.2 17 130 40 7 7.2 09 0.1 1.2 126 809 8.1 0.5 03 2.9 128 8.2 5.2 05 03 2.7 131 37 4 91 0.6 0.2 22 128 49 2 9.2 0.4 0.3 3.6 1196 •6.2 10 1 0.6 0.2 24 83 5 -17 7 10.2 0.7 01 l6 47 1 -11 7 11.1 0.8 01 1.3 21 5 -3 2 11.2 12 -01 0-9 10 3 30 12.1 11 0.0 10 58 -3 3 12.2 1.3 ’O.1 0.9 5.1 -3 7 Annual 0.4 0.3 3.2 1541.2 575.1 Water Werks Design & Supervision Enterprise In Associate Kiln 1 QwncQfi[ineiiLaJ Consultants ana Technocrat* Prt Lu.ArJChD^sSil Irrigation Projul Meteorol^lea^n^lylrologicaULspectB labia 5.6: Half-Monthly Rainfill Magnitudes at Different Reliability Level* ■ay 2007 Month Avg Rettebtfity level ___ 55% 60% 65% 70% 75% 80% 05% 90% 95% 7 5 4.41 3 43 2.49 1 56 0 69 0 0 0 0 1,1 7.6 4 3 09 2 24 1 45 07 0 0 0 0 1.2 88 2 46 1.38 0.41 0 0 0 0 0 0 2.1 96 5 52 4.22 2.98 1 77 06 0 0 0 0 2.2 20.6 13.2 10.5 7.87 5 25 2 64 0 0 0 0 3.1 33.0 24 4 21 1 179 14 6 11 4 8.08 4.61 0 62 o 3.2 22.7 15.2 124 9 67 699 4.32 1.61 0 0 0 4.1 46.7 34.9 30 251 20 1 15.1 9 86 4 25 0 0 4.2 76.2 59 6 52.8 46.1 39.5 33 263 19.4 11.9 3.32 5-1 102 6 34 27 77.2 70 28 63 42 56 51 4943 42 02 33 96 24 5 3J 119.6 101 92 5 83 9 751 65 9 56.3 45 7 33.6 18 3 6.1 123.2 106 982 90,7 63.2 75 5 67.4 58.7 48.9 36 8 6.2 122 1039 97 46 9126 85 17 79.13 7304 66.78 60.14 52.6 71 123.9 110 106 102 99 2 96 93 90 1 87.2 84.2 7.2 116.5 102 95 7 889 82 74.9 67.3 59 49.3 37 a.1 121 8 110 104 99 93.6 67,9 82 75.6 68.2 59.1 6.2 120 108 103 97 6 92 7 87.6 62 4 76.9 708 63.5 91 108 5 97 9 921 86.1 80 73.4 66.3 584 489 36 1 9.2 73 7 58.7 52 5 462 40 33.6 27 199 12 2 37 10.1 41 8 292 24.9 208 168 128 877 4.68 0.38 0 10.2 11 1 11.2 19.7 13 l 11.1 9.3 7.54 5.83 4 16 2 5 0 82 0 11 8 4.15 2 92 1.83 0.85 0 0 0 0 0 6.1 2.02 1.21 0 46 0 0 0 0 0 0 12.1 66 0 83 0 0 0 0 0 0 0 0 12 2 1453 1353 7304 1253 1202 1148 1090 1025 950.5 853 Annual Waier Works Design & Supervision Enterprise In Associate with IntMtonunanul Consulunis and Technocrats Pvt. LtdAr Jo Dcdessa Irrigation Project Meteorological and Hydrological Aspects May MJ7 Taw» 5 7 Marf-Monlhly Rainfill Magnitudes m Percent nt Iht Mean Corresponding Io Different Reliability LiJmels Month Avg — Reliability level 55% W% 65% 70% 75% 80% 85% 90% 951. 1.1 100 59 46 33 21 9 0 0 0 0 1J 100 51 40 29 IS 9 0 0 0 0 2.1 IDO 25 16 5 u 0 0 0 0 0 22 100 58 44 31 1& 6 0 0 0 0 31 100 64 51 38 25 13 0 0 0 0 32 100 74 64 54 44 35 24 14 2 0 4,1 100 67 55 43 31 19 7 0 0 0 4.2 100 75 54 54 43 32 21 9 0 0 5.1 100 76 68 59 51 42 34 25 15 4 5.2 too 52 75 68 62 55 48 41 33 24 0.1 100 64 77 70 63 55 47 36 28 IS 6-2 100 86 80 74 68 61 55 46 40 30 7.1 100 85 60 75 70 65 60 55 49 43 7-2 100 89 66 82 80 77 75 73 70 68 51 100 &a 82 76 70 64 58 51 42 32 6.2 100 90 85 61 77 72 67 62 56 49 3.1 100 90 86 61 7? 73 69 64 59 53 9.2 100 90 85 79 74 68 61 54 45 33 10.1 100 80 71 63 54 46 37 27 16 3 10.2 100 70 &D 50 40 31 21 11 1 0 11.1 100 66 56 47 38 30 21 13 4 0 11.2 100 35 2$ 16 7 0 0 0 0 0 12.1 100 33 20 £ 0 0 0 0 0 0 12.2 100 13 0 0 0 0 0 0 0 0 Annual 100 93 90 86 83 79 75 71 65 59 Vj Water Works Design & Supervision Enterprise In Hsflciate with inttrmttaentaj Consultants and Tfchnocmts Ptl LtdAjjo-DvdKSl [rrtfati&n Project Me te o ro I a glc a I a od Hyd ru logical As pec ts Tabla 5.8 Max t mum Annual 24-hr Rainfall ____________ Hjy__gw£ Vear (rnrn/dj Vear (mm/d) YMf (mmsd) 19B7 47 1 1980 45.6 1993 50 1 196S 47 0 1981 1994 57 8 1969 640 1983 50,0 1995 61 0 1970 57 0 1984 51 7 ■■996 60 1 1971 70.0 1985 62 2 1997 104 5 1 1972 45.2 1986 64 6 1998 63.5 1973 35 9 1987 584 1999 63 0 1974 Si 8 1988 53 2 2000 47 9 1975 36 4 1989 46.8 2001 69 0 1976 47 1 1990 49 5 2002 570 1978 1991 87 8 2003 1979 45 0 1992 51 6 2004 39.1 Average 54.14 CV 0.306 Ske^r 2E-04 Table 5.9 Maximum Rainfall Magnitudes and Frequencies. Return Frequency Rainfall Magnitude [rnm> Pe«so (T) Factor (Kj 24-hr 1-hr s -0.16 51 27 5 0.72 66 35 10 l 30 76 40 15 1 64 82 43 20 1 86 85 44 25 2 04 88 46 30 2 20 91 48 40 2 40 94 49 50 2 61 SB 51 Water Works Design & Supervision Enterprise In Associate with loiertcnuuEiitiil Ceasuliants and Technocrats Pvt. ltdArje Dedtssa IrrtciiLni Project meteorological and By dro logical Aspects TAfita 5L10 Maximum Ramfalt Mag n irudv* for Hi?h«r Duration! Majr 2007 Ftalurn Way Awg. of Mu. Penod,T (Yiarsj EVI Factor K(T) Max 2day Rainfall immi Max. 3day Rainfall (mm) 3 day Rainfall |mmj 2 -0.164 70S 92 7 29.6 5 0719 94.6 112 7 37 6 10 1.304 106 3 125 9 43.2 15 1 634 1129 133.4 46.2 20 1 865 1175 136 6 46.3 25 2 043 121 0 142.6 49 9 50 2591 132 0 155 a 549 L— - 3J» 142 0 167 3 59 9 Water Works Design & Supervision Enterprise In with immoniinsnui Consulums Mid TechnocrtiA Pvt LtdArjo-Dedessi LrripliDD Project Meteorological and HydroiogicglA^pms Miy awn i" i" i- „ .200 9000 1 .py, rMKl iO65 19*0 W5 W ’’Wi 1^C' Year 20W Figure 5.1(1 ) Trend Analysis of Annual Ri infall at Jimrrtl Slaton M ri ri ri i i I i Figure 5 1(b] Trend An*ly*j» of Annual Rainfall «r 0rdell» Slation ___________________________________________ 42 Water Works Design & Supervision Enterprise Id Ass^fe with IntETtDDUnequl Consultants ind Tarmac ruts hi Lid.AJJ<i Dsdesia JmglUaE Project Meteorological and Hydrological Aspects May ?0O7 Figure 5.1(c) Trend Analysis qt Annual Rainfall at DeuEssa Station Fiflura 5 24a) Single Meat Curve cl Jimma Ramfall 4* Water Works Design & Supervision Enterprise In Associate mth InieroentinenUil Consultants and Techoomts Prt. Ltd.Arjfl Dedrn* Irrtgailun Frajeet Meteorological aod Hydrological Aspects 2007 53NX' Vcjri Figure 5.2(b) Single Mass Curvt Q< Bedellc Rainfall >BTO >575 ’WO TMS i99C- 1W5 2COC 2005 tears Figure 5.2(c): Singie Mass Curvv af Dedassi Riinfall 44 Water Works Design & Supervision Enterprise [o Associate with latttvoiittMQtal Consulunu andTKhnocnis Pyl ltd.ifjfl tadUSl imtatlop Project Meteorological and Hydrataglcal Aspects Ml) zoo? 300 Water Works Design & Supervision Enterprise la tes'diEt withinunmmnMtii Coiunlujua 4rd TwhhQ mts Prt Lta CArjo Dedess* IrrigatiDa Project Meleorological and Hydrological Aspects 6. MONTHLY STREAMFLOW ANALYSIS 6.1 Hydrological Observation Stations Hyorgmeinc stations on me Odessa river and the neighbouring nvers within the Abbey basin lhe Omo-Ghibe basin have also been identified The hydrological daia are obiamed from ir.c Hydrology Department of the Ministry of Waler Resources fMoWR] There are two hydrological observation stations located on the Dedessa Rive* These are Dedessa near Ago town (Station No 114001j and Dedessa near Dembi town (Station No 114014). Station 114001 with catchmeni area of 9981 Km3 is located about 44 km downstream of the proposed dam sue ano nas become operational since i960 where as Sial on 114014 with a catchment area of 1806 km3 is located about 137 km upsiream o1 the proposed cam site and has become operations, since 1985 Besides the two hydrological observation stations located on the main Dedessa over several hydrological observation stations are located on its tributanes. In addition. nydro»ogicai Observation stations on the neighboring Daoana n ear A oasma ( Station N o 114Q05) < Giige; Ghibe near Assencabo (Station No Q91008j, ano Gojeb near Shebe (Station No C9iDi2i have been 1ound la be relevant to the study The list of hyaroiogical ooservation stations for which data have been collected along with other details like their location and catchment area is available m Table 6.1 6.2 Extension of records Streamflow gauging stations have peen installed on the Dedessa River near Arjo town [Station 1-4-001 j since i960 ano near Demth town (Station 14Q14) since 1985 Before the streamflow analysis, data obtained 'rom Station 114001 (Didessa near Arjo) ana Slation 114D14 (Didessa near Demoi) were checked for temporal and spatial homogeneity The investigation pl nomogeneiiy was concentrated mainly on the outliers of the monthly data senes o1 the recoro Extremely high or low values of each senes, that nas occurred at time T(i) m each month M[il. was checked agamst the records of the mooih M(i-1) and that has occurred at the same year T() so as to judge, wneiher the relation i$ still more or less the same as that of the atner years. Whenever the outliers were rejected by this lest, agam another test was performed wth -------------- ------------------------------------------- --------------------- ----------------- ----------------------------------- 4n Water Works Design & Supe rvlsl on Emerprts e la Associate with Intertonuaental Consqlticns and Technocmis Pvt Lid.Arjt- DcdtisSl Intuition Project Meteorological and Hydrological As;pecta May 200*7 other Gala senes ot Station 114005 (Dabana near Abastrta), Slaton 91006 {Giigei Gnibe near Assendabo} and Station 9i0i2 {Gojeb near Shebe) for the same penod TO) The data were checked Tor ils consistency before use for different analysis, The investigation will concentrated mamfy on the outliers of the monthly and daily data senes. Extremely high or low values that occurred at a given lime were checked against records of other near by nve*s (such as Dabana) If the outliers are found to be inconsistent with others then they were replaced by new values tnat were generated regionally from dais set obtained irgm other stations. 6.3 Synthetic flows In this section. analysis of monthly flows is made with the intension of improving information requires fro reservoir storage design. Reservoir siorage design on the basis of generaiec (synthetic^ flows is preassumec It was realized that the specific sequence of historic events was a random pecyr-ence that would certainly never occur again m the same way To get some idea about other possible sequence wifhir the population, m order to improve reservoir design, generating a long streamflow senes is a highly acceptea procedure by hydrpiogisis However, it has oeen oointed out synthetic (generated} flows do not improve poor records Dut merely improve the quality oi oesigns mane with whalever records are available. Mean monthly discharges, coefficient of variation of monthly flows Summary of regional monthly flow characteristics statistics ot monthly flows at Arjo Dedessa Dam Site are shown by aoles 6 2 6 3 6 4. 6.5 respectively The monthly stream flows at different reliability level are available in Tame 6 6 In order to maintain the historical skewness m the generated flows the Aieibull distnbution has been fitted io me standardized residuals or the monthly senes Accordingly the estimated parameters or the random generator that were usm in the Thomas-Fiemng model are presentee in Taoie 6 7. ------------------------------------------------------------------------------------------------------------------ --- -------------- 4* Water Works Design & Supervision Enterprise In. Associate u'lui laurcontlnetital Consultants and Technocrats Pvl Ltd.XrJ o D&dessa Irrigation Project Mete pro logical and Hydrological Aspects May 2007 Mone details on various results are shown ir the annexure B 'Results obtained Iron hydrological analysis." The (lows at the dam site at annual level are as beiow Mearyear 75 % year 80 % year 90 % year 95 % year 2328 Mm! 1729 Mm1 1625 ' 1384 ■ 1224 ‘ Tish 6.1 Aviilability of Slr»*mfldw Data in the Region Si hC Si he Station name and Location Let North Area Flow IMm’ryrj R li noli |mm) 1 114001 Dedessa near Arjo 8 41 36 25 9981 3826 383 2 114014 Upper Deaessa near Demoi 6 02 36.28 1806 1221 676 3 114005 Daoana near Aoasma 902 36.03 2281 1870 820 Gilgei Gibhe near 4 091008 AsenOabo 7 45 37 11 2966 1211 408 5 091012 Gpjeb near Shet>e 7.25 36.23 3494 1803 516 Table 6.2: Mean Monthly Flow (in Mm’fseci Si. No Jan Fab Marc h April May June July A ug Sep Oct h ov D ec Annual 114001 114014 114005 41 9 26 7 26 33 5 63 6 216 646 1050 902 526 148 80.7 12.2 9.5 11.5 169 36 4 112.4 228 9 306.9 262.8 154 3 48. 4 20.5 35.4 19.8 16.3 17 Q 351 107 0 258 8 433.0 473 4 313. 9 103. 3 56 6 091008 901012 14 7 13 5 12.2 15.9 33 9 100.3 2l6 5 319.2 277.8 13 7 60. 2 24 5 31 3 22 1 22 1 31 3 86.4 169 2 323 7 415 6 400 9 202. 3 82. 8 465 3761 1221 1870 1211 1803 I Table 6.3: Coefficient of Variation of Monthly Discharges SL ho Jan Fab Much April May V40C1 0.51 0 57 0 66 068 0 62 114014 0.47 0.5 0.48 0.56 069 114005 0 28 0 42 0.33 0.43 0.60 091008 0 46 0 58 0 78 0.45 0 43 901012 079 0 36 L. J _ 0.34 043 D63 0 44 0.31 0 26 034 0 49 054 0 70 June July Aug Sep Oct hov Dec --------- 1 0 45 D35 0.3 0 33 0.67 0 62 0.59 0 53 0.29 0 27 0 30 0 56 0.81 0 53 0 47 0.20 0 16 0.25 0 44 0 30 0 34 0.36 0.22 0,28 0.27 061 0.79 0 58 ----------------------------------------------------------------------------------------------------------------------------------- Water Works Design & Supervision Enterprise In itswciais ttilh iQitnmrrtmttJlnL Consultants md Tectonrrats PYl. Ltd 4S a *!AjjDDsdflSSB ImgaLlUU PrDjttI Me Leoro! o gi cal an d Hydro) ogle a] Aspects Table £ A Sum miry of Rug oral monthly flow G haritle rlstics May £00? Param Year Jan j Feb M»r Apfil May cv 194 i 0 51 0.68 0 595 0.5B Q61 Siifrbv 151 1 BO 1 66 i 503 0 B6 1 fiS R 194 0 3fi 0 57 0 527 045 049 fi 194 0 34 0 76 0 46 044 052 June July Au-i Sep Oct Nov Dec 0 47 'a.33 0.29 0 32 0 58 0 66 Ij 57 1 05 a 12 0.7 0.59 0.94 2 1.9 2 02 0 66 0 53 0.56 0.51 0.5 0.56 0 51 0.51 0 37 0.5 0 56 091 0.64 0 44 Table 6 5 Tibbe Statistics of monthly flows al. AfJo Dedessa dam srte i in hliilioii m*i Pi rim Jan F*U Mar A;>r May_________ Jun Jul Aug Sep Oct H ™ -=— ______ ____ Dec Annuli 3? dev Skew Max *fln 25.00l6.97 17fifi24.2l 48.26157.2 4i2.fi 633 540-6 299 8 105 9 46.11 12 81 9 72 11.82 16 41 29.69 70 67 143.2 189 6 179.2 160 5 09 35 27 17 0 626 0.743 1 067 0.937 1 629 0-891 0 126 0.037 0.254 0 585 1 666 0 96 59.09 40 3 46.01 68.61 144 9 3fifi 1 751 5 1043 905 1 661 4Q0 fi 120 1 2328 619 3 0.498 4089 6.806 3 462 1 775 4 586 9.fifi5 3fi.7l 143 8 296 2 195 6 49 32 12 69 4 BOB 1124 R 0 446 0 828 0 889 0-59 0.296 0.765 0.45 0.529 0 436 0 431 0 796 0.704 fl 0.2l 0.62fi 1.081 0.819 D.54 1.6680.9120701 0 412 0 434 0.394 0.214 Title 6.&; Reliability Level Vl Monthly Streamflows al Qarti Site [7n MmJ Reliability Level Jan Feb Mar Apr May Jun ■All -Aug Sep Oct Nov Dec -----------1 4 17. i 55 20-2 12 7 14 1 19 3 3? 5 T3i 4 371 1 56B 8 400.4 239 75.$ 35.5 2114 60 19.0 11 6 13 O 17 4 34 7 122.3 34fi.4 $4? 8 454 6 216 6 69.0 33 2 2019 65 17.9 10.6 12 D 15.632.0 H3 5325.3 518 7 429 0 1 94 7 64 631.1 1924 70 16 9 75 16 0 BO 15 0 9 6 H 0 13.6 29 5 104.9 301 3 490 S 403 3 173.1 S9.fi 29.2 1828 0.7 10 1 11 927 1 96.4 276.Q 464 5 376.9 151.6 55 0 27 4 1729 7 0 9.2 10 124 9 87 8 240 5 437 3 349 4 129 7 5Q.9 25 7 1625 85 14.2 59 0.3 8 1 226 78.92l7.fi4Q&.3 3l9 $ 107 047.024 1 1512 90 133 Bl 7 4 6 0 20.4 69 5161,2 376 4 286 7 82 5 43.5 22.6 1384 95 12.5 5 2 6.5 3.518.2 59 0132.1 337.9 246 0 54440221 2 1224 L_A¥fl_______ ______________ Waterworks Design & Supervision Enterprise In tatoElite with [aHrtQntlaflniAi CrmsultMis and Technocrats Pm, Ltd.Arjo Dedessa Irrigation Project Meteorological and Hydrological Aspects Ma? 2007 Tabla 6.7 Characteristics of Random Numbers Used for Flow Generation Param Jan Fib Mar Apr Jun Jul Aug Seft Ctal WOV Dec Average 0 00 CV 0.51 Skew 1 80 0O0 0 00 000 0 00 0 00 0 00 o.oo 000 0 00 0.00 0 00 060 0 60 0 58 0 51 0 47 0.33 0 29 0 32 0 58 066 0 57 1 66 1.50 086 1 65 1 05 0.12 0 70 0 59 0 94 2.19 2 02 088 1/a 0 933 7 0 834 0 620 0 883 0 683 0 373 0 567 0 530 0 647 1 063 1 007 0.05 y|aj 0 033 7 0 083 0 190 0 058 0 158 0 313 0.217 0.235 0 177-0 032-0 003 1.15 2(a) 1 081 6 1 262 1 978 1 162 1 713 3 543 2 241 2 444 1 860 0 948 0 993 Weibui Distribution X=E+ U - Xm +Cv'Xm"y(a) _ E_= U^Cv'Xm'z'a} 5n Water Works Design & Supervision Enterprise In Associate with Intercontinental Consultants and Technocrats Pvt. ltd.ArjoDwlessi Lrrifitioo Project Meteorological and HydrologtcaMspects 7 ESTIMATION OF FLOODS FOR UNGAUGED CATCHMENTS in the hydrologic analysis for dams, weirs. bodges and drainage structures it must be May 2007 recognized that Ibere are many vanable factors mat affect floods Some of the factors that need be recognized and considered on an individual site by site basis are o rainfall amount and storm distribution. o catchment area size, shape and orientation □ ground cover; o type of soil. o stopes of terrain and stream(S), o antecedent moisture condition o storage potential (overbank, ponds wetlands reservoirs, channel, etc ), and o catchment area tn g eneral t nree t ypes o f e stimation I foods magnitudes (namely i he R ationai M etbod, S CS method and Transferring Gauged Daia method) can be applied for the project area. 7.1 Rational Method The Rational Method can be applied to small catchments if they do not exceed 12.8 km‘ (or 5 square mile) at the most (Gray 1971) The consequences of applying the Rational Method to larger catchments is to produce an over estimate of discharge ano a conservative design The method is nevertheless trequently used in standard or modified form for much larger catchments. This is because of its relatively simplicity The vast majority of catchments producing flooos imposed on tne command drainage system lie within the validity o1 the Rational Method and it has been used as the principal methoa of estimating design discharges of dykes, culverts, drainage channels etc The Rational Methoa is oasea on the following formula Qm = 0.2778 C.IAFr where Qm = peak flow corresponding to return period of T years in m^sec C = a runoff coefficient expressing the ratio of rale ol runoff to rate of rainfall (see Annex C1 ano C2). Water Works Design & Supervision Enterprise In Associate with Intercontinental Consultants and Technocrats Pvt, Ltd.Arjo-Dedessa Irrigation PtoJmi Meteorological and Hydrological Aspects __ ________ ___________ i = average maximjm intensity of rainfall in mm/hr. far a dural.on equal to the lime al concentration, A = drainage area rn knr. Fr = is the areal reduction factor (this factors improves the catchment limitations imposed on tne use ol rational melhod}. Coefficient of runoff C lor lhe formula are given by many soil and water conservation texts (see Annex C.lj. information on rainfall intensity I in a time or concentration (time period required lor flow io reacn itie oullel from lhe most remote point in ine catchment} is required and can he estimated by me following formula The selection of the correct value of C ' presents some difficulty It represents a parameter lhal can influence runoff including, soils type, antecedent soil conditions, “and use, vegetation and seasonal growth Therefore, the value of C can vary from one moment to another according to changes especially soil moisture conditions Tc = (1/30B0)xL*lSa (Kirpich equabon) (7 2) where Tc = lime pf concentration (in hours). L = maximum length of main stream (in meters). h = elevation difference of upper and outlet of catchment, (In meters). The area reduction factor (Fr) is introduced to account for the spahal variability of po«nt rainfall over lhe catchment This is noi sigmlicant for small catchments Out becomes so as catchment size increases. The relationship adopted for 'Fr is based on that developed for the East African condition (Fidd&s, 1997) The relationship can oe expressed as. where Fr = l -0 02 djbA’m D = duration in hours, A = drainage area in xm . (7 3) 2 This equation applies for storms of up to B hours duration. For longer durations on large catchments the value of D can be taken as 8 for use in the above formula 52 Water Works Design & Supervision Enterprise In Associate with l-iiiercori ilneata I Consultants arid Taclmotrars Pvt. Ltd.Arjo D«fe$si IrrttlUop Project Meteorological and Hydrological Aspects 7.2 SCS Method my w A relationship peiween accumulated rainfall and accumulated runoff was derived oy SCS (Soil Conservation Service;. The SCS runoff equation is therefore a method of estimating direct runoff from 24-hour or 1-day storm rainfall. The equation t$. Q = (P - La) flP-la) + S ? (7 4j where Q - accumulated direct runoff mm P = accumulated rainfall \potennai maximum runoff), mm la = initial abstraction including surface storage, inception, ana infiltration prior to runoff, mm S = potential maximum retention, mm The relationship Between ta ano S was developed from expenmeniai catchment area data H removes the necessity for estimating ia ror common usage. The empirical relationship used m the SCS runoff equation is la = 0.2xS (7.5) Substituting 0.2xS for la »rt equalion 7 4 me SCS rainfall-runoff equation becomes Q = (P-0.2S) f(F*0.8S) s {7 6) S is reiated to soil and cover conditions of the catchment area through CN CN has a range ot 0 to 100 (can oe obtamiM from Annex C3 and ERA 2002;, and S is reiated to CN by S = 254x[(lQQfCN)-*] (7 7) Conversion 1 rpm a vetage a nteceaeni moisture conditions to wef conditions can be d one by multiplying the average CN values by Cf [where Cf = (CN/lOO) '3<j -------------- ---------------------------------------- -------------------------------------------------- 5? Waler Works Design & Supervision Enterprise la Lssodaie wtUi Intartwmnentaj Consultants and TMhnocrals Pvl Ltd,Arjo Otdessa irrtfaiLun Piojeci Meteorological and Hydrological Aspects May 2007 7.3 Tran sferr ing Gauged Dat a Gau geq qaia may be Iransferred to an ungaugco site o' int erest provided such dat a are nearby (j e wilhjn the sam e hypnniD gic regi on, and there are no major tributar ies or d iversions between the gage ano tne site of interest? These procedures make use of tne constants obtained in developing the regression equations These procedures are adopted from the work, of Aamasu 0989/ as fallows. [7 Bf where a 2 Au =■ ungauged sile catchment area (km ). Ag = gauged sue catchment area (km ), The estimate daily (or the 24-hr) annual maximum Hoot could be converteq into a momentary peak as, Ou Qg^AufAgj11 rD Qu = mean annual daily maximum flow ai ungaugea site Og = mean annual daily maximum flow ai nearly gauged sire {m /sj, 2 Qp = Cf. Ol (7.9) Here, Cf is factor estimated as Cf - 1 * O.SfTc (where, Tc is lime of concentration). 7.4 Estimation of Weighted Average In general, the Rational methoa SCS method ano Transferring Gauged Daia are recommended 1<x rerahve^y small, medium ano large catchments respectively However, ii is very important io esiaotish a smooth pattern qt transition from small to medium and from medium io large catchments. Accordingly (he recommended weighted average estimate of peak flood can oc given as Qw = On + W Q + Wi.Ch 2? (7 10) ------------- ---------- -- ------------------ —. ___________________________________ 54 Water Warks Design & Supervision Enterprise In Assoclats with IntBrconttnenul Consultants and Technocrats Pvl LtdAj)oDede55i Irrigation Project Meteorological and HydroJdgical Aspect-4 where. Qi Qi and Q are mean anhuai momentary 3 Transferring Gauged Oala method* reipectivtiy Mi) 2OC7 eshrnal&d &y Rai ona- SCS anj W, W; ana W3 are weighing Tactor? cF mean momentary pea- eshmalK by Ral»na> SCS and Trah$(emng Gaugea Data methods respect, veiy and Wi - 12 5r(l2S^Au) ( 7 11) Wi = (Au.'Aqf70 0 t?i Wj =1-(Wi + W3) if 13> Where Ag and Ay are gauged and ungauged site catchment areas, respectively 7.5 Synder Method of Constructing Synthetic Hydrograph The Synder memod has been usea extensively to provide a means o< generalmg a syndetic ymt hydrograph The i-ol lowing steos are used Stea 1 Detemvne the lag time. T. ol the unit hydrograph Tne lag time is me time from me centroid Ol the excess raanlgll 1q the 1o the hydrpgrpph oeek Syndgr oerrvpd the Iqlkfwing empirical equation for lag time Tl = Ci (L Lea)" (7 44) where T L = lag lime (in hrs). L = length akjng the mam channel h*m cmnei to Oiuiae (in kmi, lea - length along the main channel from the outlet to th? point opposite th* catehmem area centroia m km. and Cl = an empincai c&ellicent ranging lrcm 1.36 io 1 66. For Ethiopian condition. Ci can be estimated be. ct □ 4 + O.WfeS'111 S = slope of 1he main stream Water Works Design 4 Supervision Enterprise In Associatewilt) Inure on tin omul C4nsull>nLs unt| Tt-CJltioCnti Pvi. Lit!ArJn-DEJess* InljiUop Prcjuct Meteorological and Hydrological Aspects Ste p 2 Determination pf nydrograpn duration The relationship developer Dy Synder for " -■ durgiipn of me excess rainfall. Tr in 4 a function of Inc 1391™ canpuiec above May 2007 T fl - T /5 S l (5.15) This results m an initial, value for Tft ot TJ5 5 Hcwwer 3 retatrotiMp nas bean de-eiope^ to adjusi the computed iag lime for other durations Thu is necessary because the eQualux1 3tJQue results in inconvenient values Ol unit hydrograph duration The adjuSlrT4b! relationsnip 1$. Tlfwfl) T * 0 25(1^ - Tr) t (7 18) where T,; adj h js the adjusted lag time Far the new duration T . fl H The unit peak discharge can tie determines Irofn I he (ollowng equation Up ’ (1/2040>{0 B4 - li'PfcfS 08 - Jn Tc)Sl wfiere. Up ■ unit peak discharge [m Tc - time o4 concentration (m hrs), The peak discharge Qp 15 computed Irom Op = up A (P - 0 2S]7 /(P+0 88) and the time from rise Qt the hydrograph (p tno peak, Tp. is COmpured irpm Tp - 0 5 TRh * V(adp (7 171 (7 1Q1 (5 19> Finally the nyarograph can tw constructed using T^Tp and Q/Qp values iwesenteg m Table Water Works Design & Supenisttm Enterprise in Awriflaifl with Intcrconunenta] Daniuiunis uid ffchnwrits Pn LidrVJd Ptdessa Irrigation. iicijtri Meteoralagical and Hydro]ogkat Aspects May 2007 fable* 5 1 to 5 3 show csiinuicd m^n flood J at seven relative I) la^t caicHmcntt crowng cwnnLand ires irwm ihc left and nghi bank directions Tabic 5,1 l.ucalEon of Proposed Lroil Drainages and Calchment Chara ctrislir! Cachm- *nt Area Scream Max- Eiei Length Min. Elev. Stream Slope C :(for National Method! CN scs Method (km' (km i im ash im ash (%) 1 CDR-16 27/5 15.50 2400 13 3f? 0.0725 U 24 71 2 CDR-19 4025 13 50 2360 1339 0 0756 0.24 71 3 CDR-28 3300 17.40 2480 1338 0 0t56 0 23 71 4 CDL-3 20j6O 9 00 17SQ I34O 0.0489 0.22 71 5 CDL-25 300 00 44 00 2480 1335 0.0260 021 70 6 CD L-28 61 00 27 00 19OC 1335 0 0209 0.21 70 7 CDL-33 70 00 17.50 1990 1330 0 0377 0.22 71 Table 5.2 {'baraclcrisiicE of Flood Hydrographs COThiffir- rur Base ct Tc (time How of cone. T. r Tiiadji Tp (peak time) Tp fatty Th (kmf <m sj (hra) (hrs> (hrs) (hrs? (hn) ■thfsi 1 CDR'lG 0 935 1 43 J.SO 0.27 632 6.15 b. 76 90 95 2 CDR-19 1387 1 43 133 0.24 5.K0 5 65 6.] 9 89.39 3 CDR-28 1 137 i 43 171 03i 6 81 n.62 7 32 92.43 4 CDE.-3 1.020 ] 45 1.15 0.21 4 63 4 49 4 97 85 88 3 CDL-25 10 34 ] 4B 4 98 0.90 12 62 12.06 14 09 109 87 b COL-28 2-102 1 49 3 72 0.68 9 48 9.06 10 58 100 44 7 CDL-33 2 412 1.46 2.12 0 j9 7.03 6 79 93 09 Water Works Design & Supervision Enterprise !a iMMtftU with Intercontinental Consultants and TMbnorrAis Pit. LtdAr]<i Utiessi imr juuu Projtc Meieoroiogical and Hydrological Aspects lablr 5.3 Eiltaiattd VcraJJr Hoodl Mar 3opz (ichmenl Qlh Rational Method QUl scs Method bin kdmaiu % Q*vk (Weighted Method A% era*>e 1 I 1 nil R u no FT iknu (hr} mm hrn i II h'km" I 1 CF)R-H> 34 94 18 98 10 35 /9J0 2 CDH-19 5545 30.37 1232 29 74 3 CDR-2B 37.& 21 15 |U "'2 21.02 4 t [>t 3 43 25 23 30 9 93 23.11 5 CDI.-25 127 43 90 45 5" 25 79.28 6 CDL 28 35.ti 3 22.24 It 4? 21.93 7 CDL 33 62 3ft 37 56 18.14 15.94 7J3t 637 ?Ji/ JriJ 359 5/3 ______ _ 53 Waterworks Design & Supers!on Enterprise lntaswlaiBwitainttraaitaenxaJConsiUMJUsMidftehfloerMSPvi L[eL b ■j ■s uArjft Dedesu IrrifiUon Project Meteorological and Hydrological Aspects MlJ 2007 8 FLOOD FREQUENCY ANALYSIS 8.1 In troduction In flood frequency anal ysis, me objecti ve is to estim ate a flood magnitud e corr espondi ng io any required return Denod of occurr ence The resu lting relati on ship tjeiwaen m agn tude and return penw is referred as the Ci-T relationship Return period T, may be delmeo as the nme-inlervaf ion the average/ for which a particular flood having magnitude (also known as qunablej is expected 10 De exceeded A reliable estimate1 of the entire Q-T relationship cannot be obtained from small samples oi at- site data The benefits of regionalczat»on in flood frequency analysis nave been recognized at ieasi since tne work of Deirympie t1960) Nowadays, the regionalization approach io flood frequency analysis (particularly the moex-tiooa melnodl is becoming more popular An essentiai prerequisite for the .ndex-flood method i$ the stanoardization erf t ne flood dala from sites wilh different flood magnitudes. The most common practice, used also m ltns siudy is to standardize data by division by an estimate of the at-sne mean, thus Xj = OifQm (0 U Where Xi is the uh standardized flow Qi is the i" annual maximum flow Qm is me average value of at-srte annual maximum flow senes. Then the quantile QT is estimaieo as Q- = Qm X-r Thus, the mean annual flood ts lhe inoex-flood The parameters of the distributor! or X are obtained from the combined set of regional dala In this study iwo distnbutions have been jsed for flood frequency analysis. These distributions are. (3j Generalized Extreme value (GEV) distribution (Jenkinson I969j (bj uog-Logistic (LcG) distribution (Ahmed et al,, 19&8) ------------------------------------------------------------------------------------------- -------------- --------------- ----------------- 59 Water Works Design & Supervision Enterprise In Associate with Inte-rcoimncmal Consultants ind Technocrats Fvt LtdArj>DwUssa [rrljillon Project Meteorological and Hydrological Aspects KlJ 2007 8.2 Est imation of Prob ability Weig hted M om ents Probabil ity weighted moments (PWM) are useful for estimating the parameters of distributions whose inverse forms tan expridlly be defined such as GEV and LLG (Greenwood el Al 1979: and nosning, 1986). Accordingly, p rofcabilily w eighted moments (PWMs) for unbiased sample estimates can be calculated as. N m lDt = . lWX,.(l-F.f i=1 |8-3) where Xi = flocc navmg ranxeo order ol i F = (i - 0.35 j/N = plotting position of the flh ranked flood n = record length The regionally averaged prooabdity weighted moments were computed as follows 1 The standardized °WMs were computet) tor each site as Xi - Oi/Qm where Xi is tne i* standardized flow Qi is the i**1 ranked ’low and Qm is the average or the date set 2 For eacn annual maximum flood record the first two prooatulity weighted moments. PWMs. .e mlOh. k = 1 ano 2) were computed using Equation (1) 3. For each k, weighted average values of PWMs aver M sites tncludeo in the region were calculated as follows M - X, N| [miQk| Mi*= _15L ---------------------------------- 1 M £ X. Nj 1=1 ( 84j These Ml[a values were then Heated exactly as sample estimates ol PWMs for the regional standardized annual maximum flood population. LLG and GEV were fined to the standardized regional PWMs -- -------------------------------------- ----- ------ -------------------- - --------------------------- -- Water Works Design & Supervision Enterprise In Associate with liittrr: online dial Consultants and Technocrats Pvt Ltd.Ar]o ftudessi trnration Project Meteorologcai an£Hyd rological^ As peels ________ _________ Miyjwjff PWMs M10G - 1 QCKJO Ml 01 = 0.411954 AHQ2SS 0.250375 8.3 Generalized Extreme Value Distribution Jerikison (i969j introduced the Generalized Extreme Value (GEV) distribution for modeling floods It has oecome more important <n hydrology since it was recommended by NERO (1975) tor modeling annual maximum streamflows o! Bntisn rivers The GEV distribution is defined as X= u + uVkj (1 - (-In Eft The shape parameter k, can be estimated as k= 7 859 C + 2.9554 C1 wnere C — — Min,, - in 2 i2 M,w’6.M ui*3 Mict) In 3 (6 6) (a 7) (S.6) 1 the scaie parameter a = x (Mjjxj - 2 MituJ (i-2*).r(l^kj (8.9) ana the location parameter u= m<w - lafcHi - m+K)} GEV Parameters C = -0 00061 Gam* = 1 0023 u — 0.879428 a s 0.253011 k = -o.ww 8.4 Log-Logistic Distribution |,8.l0j Waterworks Design & Supervision Enterprise la Associate with Intercontinental Consultant! and Technocrats Pvt. Ltd.Arjfi Dedlessa Irrigation Project Meteorological and Hydrological Aspects Key 2W7 log’Loqistic (LlGj distribution was introduced for flood frequency analysis by Anmed et at (19B8J The LLG distribution is defined as X- a + 0.{F/(1-F)}‘ The parameters c. □ and a can be estimated as follows The snaps parameter M tne scaie parameter d- c.G (0.11) (3.12) (6 13.1 ana the location parameter a- h4 1(X -c G wnere G= trcysifiKCj LLG Paameters G = 1 05tD33 a = -0.01767 t> = 0.968257 C = 0.173014 8 5 Regionally averaged quantiles (8 14) 48 15) Generally the differences between estimates ot standardized quantiles by GEV and lLG distnbultons increases with increase tn return penoos. In all cases clear differences are observed tor the >arge return periods where lLG distribution gives larger quantiles compared to GEV distnbui>on Estimated flood quantiles based on GEV ana lLG distributions are presentea in Tables 8.1 and 8.2. respectively 62 Water Works Design & Supervision Enterprise tn Associate with Intercontinental Consultants and Technocrats Pit Ltd.ArJ d Dedetta ImgiUon Project Meteorological and Hydrological Aspects 8.6 Choice of Distribution May 2007 RoDustness as a cntena has received widespread attention tor choice ol distribution tor an annual maximum flood (AMFJ. Robustness is assumed 10 test whether a distribution and metriM or parameter estimation, considered jointly are insensitive 10 departures from assumptions maoe tn their use. In Ibis regard. LLGfPWM has teen lound to de more robust than GEV/PWM (Admasu 1989J. Otten, a compromise has to be reached between flexibility and sensitivity to outliers One may need to compromise on some kind of mid-way solution The compromise could be to use a three-parameter disinbution such as GEV and llG However for this purpose. LLG has been found to be more attractive than GEV in addition, llG is .ess sensitive(compared to G EV} to c hanges 1 n the small values of the annual maximum IIddos Therefore, LLG/PWM is Getter than GEV/PWW lor modeling AM samples thai display a dogueg shape when plotted on probability paper In general. ILGVPWM nas been found to be more appropriate for modeling annua* maximum floods (AMF] oomoareo to other distributions. Therefore, LLGJFWN nas been applied for estimating design Poods required for trie project. Thus, cased on probability weighted moments method and using Li,ift disinbution on a regional flood frequency approach, the return period floods have beer arrived at lor the proposed oam site The monetary peaks discharges at various levels of probability of exceeoance (return benoas; are summanzed beiow 10 yr return period flood = 575 m /sec 20 yr return period flood = 654 nrP.'sec 50 yr reiurn period 1 locus - 77lm^sec 100 yr return penod flood = a71nP/sec 500 yr reiurn penoa flood = 1155 m’rsec 100G yr return period tlooc = 1303 m^sec 1Q00D yr return period flood = i94flm Jsec 3 J ----------------------------------- ---------------- ---- .___________________________ _________ __ 63 Water Works Design & Supervision Enterprise [ti Assodite whh lnlercauunenta] CumuLtancs and Technocrats Pvl LieAr> Dedess* Irrigation Project Meteorological and. Hydrological Aspects Table 8 1 Estimated Flodd Quantiles Based on GEV Distribution Hay 2007 T Xt Mean Max. Daily Discharge Momentary Peak -----------------4 Return period Growth factor Gauging Site 111 Gauging Site '2i Wama it JUrtCtHjn Dtm site Gauging G Site tTi auging Site 121 TVama at Junction i ?am sfle . Jj-earsy 1 ratio i ‘“77TT. "' |m >5/ IfTp/S.r (m’rsj im7s.J im'/s'i ;m >S) ( 2 0 95 670 214 238 354 768 272 264 392 5 i 23 669 2?8 309 460 1022 353 342 509 10 i<3 1DQ1 320 356 530 1178 406 395 586 20 1 50 1129 361 402 597 1329 458 445 651 50 i S3 1296 414 459 666 1526 526 509 759 IX 2D1 1422 455 505 752 1674 577 559 833 200 219 1549 495 550 619 1822 629 609 907 500 2 43 1716 549 610 SOB 2020 697 676 1005 100C 2.61 1644 589 655 975 2170 749 726 1080 2000 279 1972 631 700 1043 2321 801 776 1155 5000 3 03 2143 685 761 1134 2522 870 842 1255 1000C 3.22 2273 727 806 12C3 2875 923 895 1331 Avenge 7 707 226 2S^ 374 632 287 278 414 The anafys/s js based on rp^pone/ flood /racpue-ncy analysis tiaseo cw? Genera/ Ejdrame Ublue (GEW dAirrtbi^iOfi iwtfi paranjerens estimated* £jy pro&aEirMy merginm? mcimwjte ^efnoo1 Table S.2 tltimaiaa Fiona Quantile? on LLG Distribution T Xt Mean I Return Growth Gauging Site period factor hi_ (years J ratio i (mJ,sj 2 0 95 672 20 1 56 1118 100 2 1 1488 200 2.38 1680 500 2 79 1972 1D0O 315 2225 2000 3.55 2511 50D0 4 17 2947 fajr. Daily Discharge iWomenrarv Peak Gauging S4e (2 Warns a; junction De/n SJfr Gauging Sue 1 Gauging Si1e I2i Wama at Junction ■** (m'/sj (mVsj ■ m3/s i <m?s? i——s—1 (m^s) m rs; m is -------- n 356 5 1 21 854 2?3 304 791 273 264 394 452 1D05 w 1 39 982 314 349 347 336 500 S19 1156 399 386 575 50 1 86 1317 421 467 215 238 357 397 476 527 S3? 597 63C 700 711 791 803 891 942 1047 591 1315 454 439 654 697 1550 535 57? 771 787 1751 604 5M 871 869 1977 682 662 984 1043 2320 800 776 1155 1177 2619 903 876 1303 1329 2956 1020 987 1471 10000 4 71 3326 Average ___ T 707 1559 3488 1196 1063 226 1153 1182 25J 1726 1750 3915 1350 ?87 1309 374 832 1948 jfj wrtfi jhomhiiu unmafaf ^Oa&hry momtrnJs metf» flea; flnnb^i— Water Works Design & Supervision Enterprise In AsocUtt muintsrt&DtlDMiAi Consultants utf Tttftnocrais Pvt. LuL - 1£ rT| EAr Jo Deaessa Irngauon Project Meteorological and Hydrologicai Aspects 9, PROSABLE MAXIMUM FLOOO May 2007 The probable maximum flood is defined as the most severe flood considered reasonably possrbfe to occur II ts customarily obtained by using unit nydrographs and rainfall information Annex C-4 gives the recommended reservoir Mood standards for three mam catego 'es o reservoirs Category A nas me mosl stnngent standards, since for suet* a reservoir a breach m the oam would enoanger the fives of people congregated m a town or village downsiream The worst conditions are envisaged the spillway aireaay taking ihe average daily inflow wnen the probate maximum Ikxw (PMF) amves ano the wave surcharge allowance must be tor heights greater than 0.6 m Categories Bano C have decreasing standard requirements In Ethiopia, the study of design flooos on the basis of PMF requires further investigation The challenging proDlem is particularly that of storm rainfall and the varying temporal pattern of intensities throughout a storm's duration, ihe occurrence ol the peak intensity is a variable to oe considered for further study at national level The initial stale of Ihe catchment is also of great significance in trie generanon or an exireme flood A thorough Knowledge of a caicnmEni ano of ns varying responses during adverse conditions 1$ essential far an engineering hydrologist to evaluate design floods and such situation need to be investigated at an institute level. However in sucn a situation where Uwe 1$ maximum rainfall data, hersfieid (1961) suggests the use cl following equation to estimate 2*nr PMP in region so as to superimpose H on design unit Hydrograph to give the PMF PMPj, = Pm +K.Sn = Pm (1*K.CV) Where PMiPs* = 24-nr probable maximum precipitation Pm = mean of the 24-hr annual maximum over the penod of record Sn = standard deviation of the 24-nr annual maximum CV = Pm/Sn = coefficient of vanation K = a constant equal to 15 Water Works Design & Supervision Enterprise In Associate with Intertondnental CdusuIimu and Technocrats Pvt Lu,Ar]o Btdtssa tmridon Project Meieorological and Hydrologirai Aspects Tihe mean annual maximum 24 hr ramlaM lor Bedele and Jimma are 55 5 mm and 5 3 respectively, ana also the coefficient of variation for Bedete ano Jimma are 0 198 and 0 20i respecuveiy For the Arjo Oedessa dam calchmeni Pm = (55 5+51 3)/2 = 53 4 mm CV = (0 198+0.2011 2 = 0 20 Sn = 0.20* 53 4 - 10 68 K -15 Then PMPj, = Pm +K Sn = Fmil+K.CV) -1 01■fffl = 4 01*53.4 = 214 nvTvday Total volume of daily rainfall Vp= A PMP^ = 5310*214 = 1129 5 Mm1 Mar 2tKr; Assuming runoff coefficient C that corresponds io the occurrence of continuous rainfall to be C.68 ihe estimated rainfall depin mai produces pcobatue maximum Ifood becomes tfpe= C Vp = 0 W'1120.5 = 768 5 Mm’ Using 1he calcnmeni charactensiics given m Table 12 1 and applying ine dimensionless hydrograph given oy Tatue C4 the Pood pea* component due to the probable maximum rainfall becomes 3502 m’rs Assuming the a base flow of 188 m /s me toiai peak flood Becomes Qp = base flow + peak due ro storm - 188 * 3502 = 3690 m\s Cumuiaiive volumes of Probable Maximum Floods (PMF) derived from probable maximum 24- J T hr ramlalt is given by abie g,i given by 9.2 design flow? hydrpgrapn derived from estimaied PMF i$ fWj Water Works Design & Supervision Enterprise la Assoelau with lnterccnLin«niAj consultuu and Ttttawcrats Ptt LtdArjo Dedtssa Irrigation Project Meteorological and Hydro log i cn 1 As pc c t s ___________________________ gv Taole & 1 Table Cumulative Volume qI Prooao:fr Maximum Flood Time (hrsj Cum. Volume Time Cum. Volume Time Cum. Volume {Mm3; (%) (hrs) (Mm3i (Mm3) (%,) 0 00 0000 000 103 50 687 8 89.5 207 00 765 3 99 6 4.M 0 440 0.06 108 00 698 7 909 211 50 765 8 99 6 900 2.936 0 38 112 50 708.3 92 2 216 00 766 1 99 7 13 50 9 389 1 22 117 00 7164 03 2 220 50 756 6 99 7 1800 21 87 2 85 121 50 723 2 94 1 225 00 766 8 99 8 2? 50 42 15 5.48 126.00 729 i 04 9 229 50 767 1 99.fi 27 00 71 51 9 31 130 50 734 4 95 6 234 00 767 3 99 8 31 50 1105 14 4 135 00 739.0 S&2 238 50 767 5 99 9 36 00 157.6 20.5 139 50 743.0 96 7 243 00 767 7 99 9 40 50 21D4 27 4 144 00 746 5 97 1 247 50 767 9 99 9 4500 266 4 34 7 148 50 749 3 97 5 252 00 768 1 99 9 49 50 322 6 42 0 153 00 751 7 978 256 50 76B2 700 0 MOO 376 4 49 0 157 50 7536 98 7 261 00 768 3 100 0 58 50 426 4 55 5 162.00 7555 98 3 265 50 768 4 IDOO 83 00 471 6 6’ 4 166 50 757 2 98 5 270 00 768 5 100 0 67.50 5li 8 66 6 171.00 758 6 98 7 274 50 768 5 100 0 72 00 546 4 711 175 50 759 9 98 9 76.50 575.0 75.0 180 00 761 0 99 0 81 OG 601 7 78.3 184 50 762 0 99 2 85 50 623 9 81 2 189 00 762 9 99 3 90 00 6434 83 7 193 50 763 6 S94 94 50 660 4 85 9 198 00 764.3 994 99 00 675.1 87 9 202 50 764.8 99 5 Water Works Design & Supervision Enterprise li> Assouan with tnunconuiiMtai Consultants and TstJinocrais Pvt Ltd.Dtdessi lrriir*[J<is Project Meteorological and Hydrological Asp eels Table 9.2 Design Flood Hydrograph Derived from Estimated PMF Maj 2007 n Or Ti -----D--j----- 1 77 . Qr Qj oQ r— 1 rnl'5,1 — ■Xhr■ j » -X. fhr.' 1 000 188 45 00 3690 90 00 1309 135 00 451 180 00 251 2 25 216 4? .25 3655 92 25 1239 137.25 433 182 25 248 4.50 241 49 50 3620 94.50 1169 139 50 419 184 50 244 6 75 339 51 75 3515 96.75 1099 141 75 402 186 75 241 9 00 451 54 00 3410 99 00 1028 144.00 384 189 00 237 11 25 573 5525 3270 101 25 958 146 25 367 19125 234 13.50 748 58.50 3130 103 50 923 148.50 349 193 50 230 15 75 958 60 75 2990 105 76 853 150 75 332 195 75 230 18 00 1169 6300 2815 108.00 818 153.00 314 198 00 227 20 25 $449 65 25 2674 110 25 783 155 25 297 200 25 223 22 50 1694 67.50 2499 112 50 748 157.50 314 202 50 220 24 75 2009 69.75 2324 114 75 678 159 75 307 204 75 220 27 00 2289 72 00 2149 117 00 643 162 00 300 207 00 216 29 25 2604 74 25 2009 119 25 608 164 25 290 209 25 216 i 31 50 2885 76 50 1904 121 50 573 166 50 283 211 50 213 33 75 3095 78.75 1764 123 75 552 168 75 279 213 75 213 36 00 3305 81 DO 1659 126 00 531 171 00 272 216 DD 209 38 25 3445 63 25 1554 128 25 514 173 25 269 218.25 209 40 50 3585 85 50 1404 130 50 496 175 50 262 220.50 209 42 75 3655 87 75 1379 132 75 472 177 75 258 222 75 206 1 Water Works Design & Supervision Enterprise In Associate with Intercontinental Consmunts and Ttchnecnu Pn Ltd.Arjo- ttedessa Irrigation Project Meteorological and Hydrological Aspects May 2007 10 SEDIMENT ANALYSIS 10.1 Estimation of Sediment yield Suspended sediment data from Stations 14001 14014 and 14005 *ere obiamed These d.scna/ges are gwen m Annex E5 Suspended concentration rates varying between 45 mcj/lt to 1670 mg-'li were observed from Odessa over Refanonsnips Detween water discharge and sediment loads al various sues in the region are presented in Table 10 1 Al site and regional approacn has been useo to to estimate sediment rates from the estimated streamflows at the dam site Accordingly, the following relationship nas oeen denved Gs = 0 078 0’5 (10 1) Where Gs = sedimeni load (in gm) Q = monlhiy mean discharge (in It/s/km') Caretui assessment regarding reservoir sedimentation will De required in the site as the life of the storage created Dy a cam is dependant of the sedimentation situation Accordingly reservoir p.annmg will include assessment of ine probabie rate of sedimentation in order to predict tne useful fife of the proposed reservoir in esiimalng reservoir sedimentation maienais originating as oed load will De assumed to have a density of 1 4 gm/cc and matenai cameo m suspension will be assumed to have a density or 1.2 gm/cc. Tne Dec load at the dam sites shall De assumed to be 15 percent of the suspended load Monthly toiai sediment load (suspenoed and bed toad) and accumulated total sedimeni load ai the reservoir site are given o> Table 10.2 and 10 3 respectively Water Works Design & Supervision Enterprise Ln Associate with lawrtoutinenul Consultants and Technocrats Kt Ltd.Ar]o Dcdess* Irrigation Project Meteorological and Hydrological Aspects 10.2 Distribution of sediment in the reservoir May 20(17 So far rhe sediment load likely io o&posjt in me reservoir rias been esiimated Bui e&iima. ng me sediment inflow to lhe reservoir is ndt enough as now high the sediment *i1 accumulai? in the reservoir is 31 w important Accordingly Area-increment method has been used i&r this purpose The method is expressed as lW2f Where Vs = AO(h-MP)+V0 Vs = sediment volume to be distributee Vo = sedimem t>eiow me new zero elevation ti = original reservoir depth from the stream oeo level ho neighi iq winch me reservoir is completely fitleo with sediment ■ e ■ heigni of rhe new zero elevation Ao surface areas of the reservoir at the naw zero elevation ana 15 tne = area correction factor The results nONathad Prom the analysis of distribution of sediment in me Ago-Dedessa Reservoir are g iven in T able 10 4 Titole 10.1 Relationships between water discharge ana sediment load r—— r Mo Station Area ifasii Mooule J 10 Vyr Loss t/km’iy Vales oF C in. Qa =C iQwi1 1 3005 Guder at Guder 524 77 oc ■ '1 C025 4007 Little Angar near Gubn 1975 176 69’ 0 096 4005 □anana near Abasma 2881 453 157 0 059 4002 Anagar near Meqantta 4574 702 150 0 061 6002 Aiitj-a, al Sudan ElQfoer 17225 4 335170 1946 0 165 Arjo De&ttssa Dam srfe 5278 776 147 0.078 ------------------------------------------------------------------------ ---------------- ---------------------- ------------ Water Worits Design & Supervision Enterprise In Associate with InurennUnenial Consultants and Tarhnocrau Pvt. Ltd TO<rjo Dcdtm IrrlEitlon Project Meteorological and Hydrological Aspects May aw Tjoia ID.2: Moniflly Total Sediment Load at (tie Reservoir Srle i in 1000m3J Jan Feb March April May June July Aug S»p Oct Nov 0#c Annual —I Avg 2 46 1 33 1 14 1 71 4 57 27 2 131 1 SttMcv 1 71 101 1 11 1 72 42 17 6 62 72 CV Sittw 3.63 4 01 7 36 6 29 515 5 31 4 91 3 42 2 526 3 83 7 54 11 4 7 48 3 696 243.5 2TT 5 93 19 92 6 2.086 2 311 0678 3509 120 J T& 29 6 87 99 01 14 7 4 95 4 349 4.024 3 8 7051 1C 92 8.77 Tab I* 10 3 Accumulated Total Sediment Load ac the Reservoir Site 1■1 |7'n Jan Feb March April May Jun* Juiy Aug S ap Oct N ov Dec --------- 1 Annual V«4fB 25 0 06 0 03 0 03 0.04 0.11 0 6B 3 28 6-2 5.29 3 00 0 43 0.17 19.39 50 012 0 07 0.06 0.09 0.23 1 36 5 6 <2 4 10 6 6 0 0.96 0.34 38.78 75 0 19 0 10 009 0 13 0.34 2 04 96 10 6 15 9 9 0 1 45 0.52 58.17 100 0.25 013 011017 045 272 131 24 6 21 1 120 1.93 0.69 77.56 125 0.31 0.17 D 14 0 21 0 56 3 40 16.4 31 t 26 4 15 0 2 41 0.66 96.95 ISO 0.37 0 20 0 17 D.26O66 4 08 19 7 37 3 31 7 16 0 2.69 1.03 116.3 175 0 43 0.23 0.20 0 30 0 79 4 76 22 9 43 5 37 0 21 0 3 36 120 135.7 200 0 50 0 2 7 0 2 3 0.34 0 9 0 5 4 4 26.2 4 9 7 42.3 24 0 3 36 t 37 155.1 1J Water Works Design & Supervision Enterprise In Associate with InitrcDnunentaj Consultants uid Techncmts Pvt LtdArjo Dtdessa Irrigation Project Meteorological and Hydrological Aspects Tjdio 10.4: Distribution of Sediment in the Arjo Dedessa Reservoir Mj> W 50 yean smAment /Old Ho - 2 .03 m Ao ‘ 1.52 Mm1 c r. J4 100 /*,rs *«*'*"*«»/o^ Ho-3 42 m Ao = 3 15 Mffl j II*. Origzn>l *r<> Mm Oftp/Ui CJpJCAl *, Mm Dujarn [■rwi pwrri S«fWv>« n>r rOhJfTM J ,Mm . ,1_. 1— 11 h | MM cjpwiV i fMmJ .■ in vwinve W ftfWgpd CjptCrty W 7j 1 Mm 1234 5 6 ■y 1 2 3 ■1 5 J 7___ 1346 56 76 629 6 27 38 7 5524 591 i 1346 56 76 629 8 27 77 4 53 61 552 4 1343 48 13 466 4 24 34 2 46 61 432 2 1343 48 13 466 4 24 es 44 98 398 4 1340 39 92 331 S 21 29 6 36 41 302 2 1340 39 92 331 8 21 58 6 36 78 273 3 1337 32 17 224 18 25 1 30.66 198 9 1337 32 17 224 10 49.1 29 03 174 6 1334 24 93 140 7 15 205 23 41 120 2 1334 24 93 140 7 15 39 7 21 78 101 1331 t&?4 79 64 12 16 16 72 63 67 1331 18 24 79 64 12 302 1509 49 4 132$ 12.19 3B 24 9 11 4 1066 26 82 1328 12 19 38.24 9 20 8 9 046 17 44 1325 6.911 13.6 6 6.86 5 395 6 724 1325 6 911 13.6 6 11 4 3 765 2 239 1322 2 619 2 322 3 2 33 1322 2 619 2 322 3 1.92 150 years sediment load Ho = 4 69 m 200 years sediment load Ho ~ 5.89 m Ao- 4 90 Mm2 A o ~ 6. 73 Mm 1 Onflrfiii #W CJJMCif ■ir Ptvr5« £M>*c r _r £rrv «rw ctptcKy* Setiimt VOIU/T!« JtfVJ ■Mm iffl.i Hm' ifflj r*frnJ . 1 2 3 4 5 6 7H 12 . 3456 7 1345 56 76 629.8 27 115 51 86 513 3 1346 56 76 629 8 27 155 50 02 474 7 1343 48 13 466 4 24 102 43 24 364 6 1343 4 8 13 466 4 24 135 41 4 331 5 1340 39 92 33* 8 21 87.1 35 03 244 7 1340 39 92 331 8 21 115 1319 217 1 1337 32 17 224 18 72.4 27 28 151 5 1337 32.17 224 IB 94.5 25 44 129 4 1334 24 93 140 7 15 57 7 20 03 82 96 1334 24.93 140 7 15 74 3 18 19 66 37 1331 18 24 79 64 12 43 13.34 36 6 1331 18.24 79 64 12 54 1 n 5 25 52 1328 12 19 38.24 9 28 4 7 297 9 887 1328 12 19 38 24 9 33 9 5 457 4 326 1325 6.911 136 6 13 7 1325 6 911 13 6 5 13.7 1 72 Water Works Design & Supervision Enterprise In Associate unin Intercontinental Consultants and Technocrats Pvt LtdArJ& Dfldessa JrrlfaliDQ Project Meteorological and Hydrological Aspects 11. WATER QUALITY May 2007 Tha watsr quality status oi ihe Dedessa nver j$ evaluated using the data collected from Mo/vR database At>t>ay River Basin Master Plan Study Report (1S98). The samples were laker as pan of i he supporting measurement for tne aqu3t'c Study and appear i o r epreser u he o niy available data an water quality within Jhc catcnmeni. . able 11 ■ shows water quality measurements taken lex Dedessa at two sites The samples were taken as Dart of the supporting measurement for tne aquatic sludy and appear to represent ihe only available data on water quality within the catchment The samples snown in Table 11 1 were taken after me sian af Ihe ramy season and presumably ail tributaries of the over exhibited adequate waief quality at me time oi sampling Total Dissolved So/jos fTDS) and E/ecfrieaJ Conduchv/fy (EC) Total dissolved solids characterized mamiy by major amons ano cakons are directly related io tne electncai conductivity of the water The tow Electrical Conductivity (EC, and TDS value m general shows mai the water is soli m nature and has low salinity Moreover the low conductivity is sign of low fertility of ine water wim regard to aquatic life, Electrical conductivity (EC} measurements wore very low ai all the sampled sites EC is the ability of 1he water io conduct electric current and directly related td the amount of canons ano anions in the water pH The pH vasue is the measure of me concentration of hydrogen (H+) ano hydroxyl tOH-J ions in ihe waier n is to determine ine acidity or alkalinity of the suostance. Sodrum and Potassium The Na' ana K' reading expressed m terms of Sodium Adsorption Ratio (SAR) is the useful parameter for the evaluation of the water body for irrigation purpose For irrigation water it is important to measure me sodium adsorption ratio as follows sar = —------—--------- (9 1) [(Ca” * Mg”VJa 5 71 Water Works Design & Supervision Enterprise In Associate with IntercontUitnial Consultants and Technocrats Pvt Ltd.Ajjo Dedtsia IrngatLon PtoJmi M ete o ro] pgit a I and Hydrologies I Asp eels The higher she SAR vaiueof the waler the I ess suiiab e will be t<x irrigation purposes The maximum computeo value among the readings is 0 29 which <$ l#ss ihan 0 Tins • lustrates that rhe waler is ^ery much suitable for irrigation purpose. Chio/rtfe The cmonae cemcanirat^n of the riv«s stipulated in T soles 11.1 is very iw (1.01c 2 0 mg/H at times ol sampling Hence the paramew was m conformity with the standard set by EP A (ZSOmg/l for aquatic species>. Table 11.1 Water quality results for sites on lhe Dedessa river Sampling Sample date at Btdtle bridge at G-mbi ondtje Comment 13foa.'96 14/00/96 Elevation (m a si) 1300 1200 TDS igrpj'l) 20 20 N EC i sfcrTi) 60 50 N pH 6 74 6 97 N Na" 3.3 3.0 N «’ 1.9 2.5 N Ca" (mgrt) 64 96 N Mg" {iTig/l) 2 43 1.4 N Cl imgJl) 10 20 N SAR 0 29 0.25 N WQ Result for Major Rn/ers rSCEOM TS96. Citea By BCEOM flbbay Rjrtr MS** ituer/, 19S8J "4 Waterworks Design & Supervision Enterprise In Associate wlW Iniertontintntal CddsuIudu and Teehngcrau Pvt, LtdA/Jo Deflessa Irrtjiticn Prcjeri Meteorological and Hydrological Aspects May wr 12. DESIGN FLOOD 12 J Synthetic Hydrograph Among several known methods of unit hyarograp ns, lhe one dev eloped by Syndor ■193 5) 'S most commonly used The method is derived fro m drainage basins in the Appala chi an Mountain regions in the united 5lalos ranging m are as from 25 km io 25.000 km T he relations of unit hydrograph characteristics ana catchment characteristics are expressed as follows Tp = Ct((LLC)” (12.1) Where Tp a lag time from the mid point of the rainfall-excess duranon Tr 1O the pea* of a unit nycrograph (hr). Ct = coefficient depending on oasm charactenstics lc = nver distance from the slation to tne point of interest nearest :he centroid of the drainage area (km) L = river distance from the station 1d the uostream limits of lhe drainage area (km) The catchment characteristics (seen as L. Lc Area Slope) of Desessa at tne Arjo-Dedessa Dam Site is given by Table 12 1 The U.S Soil Conservation Service (SCS) developed a dimensionless hydrograph that has its ordinate values expressed as the dimensionless ratio, TVTp Qi is the disenarge at any lime Ti The snape ol the unit hydrograph dimensionless hydrograph, and Tp is me period corresponding to peak as shown m Annex Table C5. For a gwen caTChmeni. once me value a1 Tp is defined jsmg Equations 12.1, rhe unit nydrograpn can tie constructed 12.2 Flood Routing Through the Reservoir The dam is located where failure may probably be confined to the irngalion command ano the dam use I No excessive 1055 of human life would de expected For such condition, a design flood corresponding 10 aiO,OOO-year return period has been proposed The volume of flow in 1000-year return period flood hydrograph is about 4OOMm3 ________________ -____________________ _ ______________ __ ___ 75 Water Works Design & Supervision Enterprise In JLsmciiie with Intercontinental Consultants and Technocrats Pvt. Ltditrjiu Dedessi Lmfail on Project Meteorologies) md Hydrological Aspects ___ MaY j 00 .'- Trie daia useu io corriplele surcharge storage due to the destfln flood and raubnp cukaABUons were inflow hyoxograpn tor all selected design storms, ejevation-sioragt refal<or>£ for propose .■ storage facility and suge-di&tiharge relations ‘or all outlet control suudurea The Kiep-by-stap method of reservoir rouung method has teen used The da-a required for the fneihad to construct the outflow hydrograph is (a) the inflow hydrograph, (b) lha cieval.on- capaciiy relation curve of the reservoir and (c? the outflow-elevation curve or the oufftow equation Using these data a design procedure is used 10 route the irifluw hydrograph through the storage facility with different surcharge storage and spillway crest ioutlet) pwmetry until the desired duiiiuw hydrograph pas been achieved A spillway with ogee shaped crestsd war has bean assumed The equation gansraffy used for such t}roaO“Cfcs;ed weir is □ s CLH15 (12 2) where □“ d'Ectiarge in m’/sBC c - bro&d-cresiw weir coefficient L= Omad’Cresled weir length, m H= head over w&r crest, m it the upstream edge of a wcu ■$ so rpunaeo as to prevent conrenirgtion and if the slope of ihe eras: is as great as me loss of need due to fnclion. flow will pass inrougn criiic&i depth ai ms weir crest: lhus gives an average C value of 2.2 The following procedures were used IO perform roulirlg through the reservoir 5reP 1 Developing art inflow hydrograph, stage-discharge curve for the proposed storage l&ciSty 2 * 2 Selecting a railing Irrhe period. Ol. Io provide at least five points on lhe rising limb Of tne inflow hydrograph T6 Water Warks Design & Supervision Enterprise la AssKtiiE wta Intarcflntineutal Consultaocs sea Technocrats hn LtdArjo EMesJia irrlgtuoh Project Meteorological and Hydrological Aspects Miy aWr w 3. using the storage-discharge data from Step 1 to develop e(praHe characterises curves that prawne value S (*/■) lOttJ-Df versus stage stop 4 Fur a given time mtervai 11 and I2 are Known Give ine oepin of storage or stage H1 at the boning of that ttflto mtervai Si - iQl -^.Dt can oe aeiermmcd frtxn the appropnato storage cnaractenslics curve Srep 6 Determining toe value of S3 + (Q2 2) Oi from tne following equation S2 + (Q2/2).Dt = [Si -(O1 2j Dt] * I when 1 J 11 + Dt] Sz = storage volume at time 2 m . sec Q2 = outopw rate at time 2 n^fSK Di = touting lime period sec S1 - storage volume st time 2. m" Ql ■ outflow rare at time 1 m^sec |1 = inflow rale ai lifHt 1 m’/tec 12 ■ mflaw rale al lime 2. m'.'SCC (12 3) grad 6 Enter me storage charactensnra curve al the calculated value of 32 + (02/2;.0t determined m Step 5 and read off a new tiepui of water. rl2 Step 7 Oeiermine the value of Q2 whicn corresponds io a stage of H2 aetormmed in Step 6 □sing the siege-discharge curve Stax? & Repeat Stop 1 torougn 7 Dy sailing values oi <1 Q1 Si, and H1 «>uaf to the previous l2. 02. S2 and H2, ana us ng a new 32 value This process is continued until the enure mflow nydFograpn has MW rauBed chrougn the storage basin Since Equation i12-3ji contains cwo unknowns, sBepw^se Inal and error procedure is used Results Of routed oes»gn floods cased on LLG distribulion, half-PMF and fulf-PMF are pressmen py Tatjie 12.2, 12 3 and 12 4. respectively Tne elevation - area capacity curves of lh& reservoir are snowr tn Figure 12 1 The lOOOOyr reium penod design inflow and outflow tiydrograpns are shown in Figure 12.2 Such inflow ana ourflpw nyarograpris lor smaller return 7n Water Works Design & Supervision Enterprise In Auatil.1* mUi iDltrt.&nlJiieniiL Consultants ADd TecJinflCrats Pm Luilrj.0 ftedMSl IfflgaUon Prajecl .Meteorologic al and Hydrological Aspects - Hay rW>. — periods fake 10 20 50 and 100 year return Mfiods are slWffi m Figure 12 3. Tne average hydrograph of mammiim flow at the dam sue ra available m Figure 13.4 12.3 Routed Design Flood at the Coffer Dam Velocity Formula The velocity equation inrough the pi&e outiei s gi^efl by V=(2gHl,) ’ where A = cross-secnonal area of barret tor cnpey, V = velocity lhrpugh the barret Hi = toLai ri&M toss inrough ihe barrel, fs H =(1.5 + fUCtj VV2g l U2.&J L =? length of me barrevpipe D/4 = R = hydraulic mean radius of lire barret D - diameter of oanebpipe 7 = velocity througn me oarrel/prpe f = coefficient of fndion Manning's Formula it is one ol the most common formula, which 13 commonly used lor me analysis of problems o1 fow through channels Put often used for the analysts ol pipe Itow problems loo According 10 this formula tne discharge through pipes is given oy V S (F^j.OOT Ssa V = velocity through the pipe. (12 6) Where n - Manning 5 roognn&$$ coefficient (3 value of 0 065 has been selected for old concrete pipe i 0 = diameler of the pipe Water Works Design & Supervision Enterprise In Associate with InttrctmtiiHnial Consultants anil Technocrats Pn LtdArj □ (touptsa [rngiu&B lloject Meteorological and Hydrological Aspects S = slope of me hydraulic gradient or energy slope =• Fu L F - is constartt equal to 0 39635 L = length of the pipe (m), n, = n*ad toss through the p*pe '.no Equalrwi 12 5 can be arranged to express me relations for head loss ihrough a pipe May 2007 hL = L Combined Formula ( 127> Corntiijirng Equal ion 12.5 and 12 7 the above two expressions for velocity reduced io Ht =11 ST2g*L Itn/FjD^}] } V V = (HJ{1 5/2g + L [(n/F; D 2Of})c'5 Q - A 5.'2g * L [(nffJD ^lV1 22 ano also = <nD'/4i (H /(1 5/2g * L. ((n/F) D" ^®}) L 2 05 (12.8l (12.9) (12 10) Where A is cross-sectional area ot pi tie in m ' J Substituting <t = 0 0165. g - 9 81 m Equation 12 8 can be expressed as hl = (0 076453* L (0 041577 V = (Hj{0.076453* L [0 041577 D V))” J1 Q = t0 7857 D:) (H^{0.076453* L [0.041577 D'2 *] })’* 2 Results of routed design flood at Cotter Dam al Ago Didassa Reservoir are presented in Table 12.5. These results are available for 10 20 50 and 100 year return period Floods. According to We criteria, the appropriate results could oe adopted tor designs Water Works Design & Supervision Enterprise In Associate with Iniercauunentai Consultants and Technocrats Pn. Ltd4rjo DEdesia imgatwo Project Meteorological and Hydrological Aspects ______ , May 2007 Table 12.1 Catchment Characteristics Arjo Dedcssa Catchment Characteristics Dimension Area (km2; 5278 Langin (km) 199 Centr<wd distance (km) 141 Max elevation (m aslj 3012 Minimum elevation im asij 1315 Elevation difference {mi 1697 S icnrrn/ 0 0085 Ct 1.53 Tc (hrsj 24 00 Tl (hrs) 33 00 T (hrs) s 4.40 Tuidj) ( 5) hr 38-00 Tp :hrsi 45.00 Table 12.2 Routed Design Flow at FRL Corresponding to 1352 m (a J Based on LLG distribution Max Surface Sore barge L.m Qdut im'/S' H -m Area (Km ) 7 Storage (Mm 50 871 397 87.06 1340 1 75 1031 3 39 85 20 1288.C 100 1154 3 02 84 01 1255 0 125 1253 2 75 83 14 1231 4 150 1333 2 54 82 47 1213 t 175 1399 2 36 _____ | 81.91 11933 Peak inflow - 1850 m3/s (b) Based on Hatf-PMF 1 L < JL_ □out m - bumj Max Surface 1 r——- Areaj-(-K.—irf£1—' i j Surcharge Storage VM”m" 1! ' 4 50 798 3 75 as 34 75 941 13198 3 19 100 84.56 1051 1270 3 2 84 83 43 125 1239 1 1 140 2 58 8261 150 1212 1216 9 2.38 175 81.97 1273 1199 7 2 22 81 45 1186.0 Peak i nflow = 1780 m&s Water Works Design & Supervision Enterprise Jn AtflocLate with IntertcnuntnuLl Consultants and Technocrats Pvt Ltd.Ar)o Dedessa trngatun Project Meteorological and Hydro! p^cal Aspects fcj Based or? PMF Mav 2007 L Oout H im) Max Surface Surcharge Area . Km‘. Storage Mm: 50 1668 6 13 93 95 1539.8 75 2008 5 29 91.28 1461 3 100 2265 4 73 89.50 1409.5 125 2466 4 32 86 16 1371 3 150 2625 3 99 87 10 1341 2 175 ______ 2756 3 71 86 24 13168 Pea* inflow = 3590 mJ/s Table 12,3 Rautea Design Flood at FRL Corresponding to 1555 m (a.j Based on LLG 1-------------- I— L ("V Qout m3/$i h , m 1 Max Surface Area i km: ———■ *———1 50 012 3 79 96.26 75 964 3 24 94 57 100 1083 2.89 93 48 125 1180 264 150 92 70 1261 244 92 09 175 1329 2.28 91.59 Surcharge Storage 'Mm1) 1601.8 1546 7 1511 9 1487 1 1468.0 1452 6 Peak inflow = 1950 mis (b) Based on Hal/-PMF= L Im Qoui rrr’/s, n m. Max Surface Surcharge Area Knr Storaoe f Mm3 i n ir— ■------tt- 50 746 3.58 75 881 3 os 95.61 1580 6 93 98 100 988 2.72 1527 9 125 1075 2 48 92.95 92.20 1495 0 150 1148 j.jg 1471 6 175 1208 214 91 63 1453 7 91 16 1439 2 Pean inflow = 1780 mj/s Water Works Design & Supervision Enterprise in Associate with ]ijtertontl etiuu CmkuHmh and Technocrats Pvt Ltd M nD B B B B ■ B B B B Bl II B B B B Arjo Bedesia IrripiUcE Project MpicorcHugical and tfydrologlca.1 Aspects ________ (Cj SasetfpnPMF l (m Qout imJ-5' 50 1540 75 1867 H rml 5 81 5 04 100 2nB 4 63 125 2320 150 2483 4 14 384 Meat Surface Area ■ Km21 102-52 IDO 13 08 S4 97 36 96 41 175 2618 3 59 9$ 64 Peak mflQVf = 36?0 mJ/s Surcharge Storage* (Mm 1611 9 1730 7 1677 1 1637.8 1606.8 1581 3 TatrtB 12 4 Routed Design Flood at FRL Corresponding to 1356m faj Based on LLG distribution Max Surface Surcnarge L(m) Qout m^s rl mJ Area (Km ) a Storage (MTn ) s 50 BDD 3 75 99 11 1693 0 76 951 3.21 97 49 1637 1 100 1069 2.87 96 45 1602.0 125 T165 2 62 95 71 1577 0 150 1246 2.42 T75 1314 2 27 Pean inflow = 1950m3/s (by Based On HaifPMF 1 95 12 94.65 1557 7 1542 0 _ llmj 50 Goul imJ/sj 735 Max Surface Area (Km*) 98 49 96 93 95.94 95.23 94.68 94.23 Surer arge Storage (Mm ) 1 75 869 100 975 126 1061 150 1134 ITS 1195 3 56 303 2.70 2 46 2 28 2 i3 1671 5 1618 2 1584 9 1561 2 1543 1 1520 5 1--------------- ---------------—------ Poak inflow = 1760 mis Water Works Design & Supervision Enterprise In AsiocLate wiUi Interiwuiifliital Consultants and Twiffltt rats Pvt LtflM& Defleisa Irrigation Pfujeci Meteorological and Hydrological Aspects (Cj SasecfonPMF Mav 2007 Max Surface Surcharge Ljm Ooul inv/s.i Him- Area 'Km*/ Storage (Mm .! 3 50 1515 5 75 1D5 09 1905.2 75 1535 4 99 102.81 1823.3 100 2086 4 48 101 30 1769.3 125 2289 4n 100 17 1729 8 15C 2453 3 81 99.28 16955 175 2555 3 56 98 53 1672 9 Pea* j'nRowf = 3690 mJ/s Taele 12.5. Routed Design Flood ST Coffer Dam of Arjo Dides5a Reservoir T-Wrs Peak = 654m].s T = 20 yrs, Peak = 654 m5Zs D O Etev D Q Etev tw 1 m3/5. [m as? (P/ imSrs.i 7nasri L 5.0 210 1337.98 5.0 211 1338 22 55 223 1333 01 5.5 225 1333.29 6.0 239 1330 00 6 0 243 1330,32 6.5 258 1325.05 6.5 263 1328 40 2x4 0 220 1334 18 2x4. D 222 1334 45 ,5 243 1329-88___ 2x4 5 247 1330 19 T - 50 yrs, Pea* - 771 m’/s 7= 700 yrs, Pea* = 871 m\s D 0 Etev D m as? o Ete* 1W. A™' im3/sJ m as/J 5.0 213 1338 59 5.0 215 1338.89 5.5 229 1333.70 5.5 232 1334 05 60 248 1330 79 6.0 253 1331 19 6.5 271 1328 90 6.5 277 1329.32 2x4 0 225 1334.86 2x4 0 228 1335.20 2x4.5 253 1330 69 2x4 5 257 1331 10 Note Length of prpe, L = 400 m Water Works Design & Supervision Enterprise In Associate with Interconuneniai Censuliants uid Technocrats Pvt. LtdAqu Ordeal lirlganon. Pr&jcci Metearologica! and Hydro logical Aspects Kay SWF Eiavaltcn-Arw«-2C-jn* for Aqo Anti |!Jn Awrrair Flflur# 12.1 6l*v*tio-ffc-A/<n-Capacrty Curv«« cf AfjO Ded&isa Reservoir Inflow iM Ourftaw rtjrirograpte <i Ajjq DMaisa ft**»r>Qir 22 Inflo* *nd Outflow f looa Hywag njpn, Jt Arto D-dM a R<»»rvOlr , Water Works Design & Supervision Enterprise' Ln Muriate with ImwrnntiatnUJ Ccnsitiunls and Tetluioerau Kt Ltd. E^vkIdh i,mJArja Dedcssa Im^auon Project Meteorological and Hydrological Aspects Muy 2007 nub. • m. t*4~i crfw a*- r 4H4 &,*•**> thmfvi** •* Qi " T " W|T*B*fc ■ ■ r> «■ in ii • — ■"I H W H '« 'n '»■ ■”T- F" r»w*m !-i'« Owi lM* ?*<■♦* Pi*. r « H JE *rjO Did IB fad irfld-dr >MH bfrl inig idiQFrF »l * rjn ti>f»BlB C«rr»i »»■ - - . t ■• v n -k i> >ib ■> __________ n-F (bril Flflurt 12.3 Inflow ina Outflow Flood tiydrojjriphi at Ar|o Dtdn» Reservoir MM "* >10 '15 ps ■•■RB a<¥"*Ha S5 Water Works Design & Supervision Enterprise Id Associate wlm Imertuntinenial Consultants and Technocrats Prt Ltd.— ■ Arjo Cedflssa Imgalicji k*rcjecL Meteorological and Hydrological Aspects May 3007 ' I — Hrdroflnph ur flew! V Arjo DMMM P*" *,r* Fiqurfl 12 4 Average- Hydrograph of Maximum flaws al Arjo Dedmi Cam Sile 8& Water Works Design & Supervision Enterprise In Ass&eiatt with InumoDdnenul Comultants art Technocrats Pvl LidVJo DeOessa Irrigation Project Meteorological and Hydrological Aspects 13. RESERVOIR SIMULATION May 2007 Determining oesign capacity of Arjo Dedessa reservoir required reservoir simulation study The factors that has been considered in the analysis include the following This particular section deals with the dam/ reservoir simulation for establishing the viability of contemplated irngat*on c Useabie flow between reservoir and diversion, o Spill past diversion weir o Flow into (he reservoir o Evaporation from the eservoir r o Rainfall on the reservoir o Total irrigation demand and o Irrigation water release from inc reservoir The simulation sample is provided in annexure 6 * S me description of vanous column, referred to there in are as oe«>w S' Water Works Design & Supervision Enterprise In Association with Intereontinraul Consultants and Technocrats Pvt LtdArju Defessa frngaUon project Meteorological and Hydrological Aspects Column Abbrev Unit Kay 2007 Ovscripffort Corp/ tear Cat ]2] Month Year Month Cat fl] inflow Mm4 Natural inflow to toe reservoir as simuialed Dy Tboma$- Feirmg model ■ monthly flows for 1QOO years) Cor /4J OF Mm3 Natural flow icorresponding to 75% reliability 'evei) between the dam site and diversion site CoJ/5/ Eo-Rf Mm Evaporation minus rainfall over the reservoir Eo is evaporation at 75% exceedance level as estimated from ETo and Rf is montniy rainfall at 75% reliability level Cor 16] IWD Mm5 irrigation water requirement (given by Table 13 ■’) Cq({7] (Eo-Rf) Mm’ Coi |5[ converted to volume covering the entire zommand area Cot {8] SL Mm3 Seepage loss \ assumed to be 1% percent of the exislmg storage tn Che reservoir) Cat ]9] IWR Mm’ Irrigation water release from the reservoir tCoi(6]-CoH4]J Cot /ID] CS Mm3 Change in storage between 1he ends of the previous and current months Cai {11] Storage Mm3 Reservott storage at the end of month Cot {12] Area Km2 Reservoir average surface area oetween beginning and end of monto Cot {13] Lewei m asi Reservoir storage at ths end of month Cat ,14] Spill Mm’ Spill from the reservcur between beginning and end of month Cai {15] STRQ Mm4 Toiai annual storage requirement Cai ]16] T Spill Mn? Annual spill from the reservoir (sum of Col114] from month 1 to 12) The d etails o f s imutalion < np ts u 3 re p rovioeo 1 n t ne T aDies 1 3 1 a nd 1 3.2. The a Dstract o f 1 he detailed imgalior targeted simutaiion runs are provided in Tabie 13 3 With these parameters the contemplated irrigation 'Table 13 1j are successful al various rehabiklies shown in Table 13 3 Water Works Design & Supervision Enterprise Id Association with Intercontinental Consultants and Technocrats Pvt Ltd.I I I I I I I I I I i i I I I I i J Arjo Dedsssa Im fulon Project MctCOrolnrif aS anri Kvrirnljipiriil A smurfs Trtte 111: (mg al ion Water ftequJreme nts tor Various scenario 5 3 {for 13700 ft J in Mm ) May 2007 Phase J Phase II Month Rod Rol2 RmI Rut? Sep 8.38 8 43 12 43 12.45 Oct 10.41 10 69 13 19 13.72 NOV 2 89 2 90 316 3.39 Dec 11 04 12 49 14 02 16 07 Jan 19 00 22 18 24 64 28.61 Feb 23 25 27 87 29 98 34 92 Mar t8 49 22 15 22 99 26 41 Apr 4 98 5 21 5 09 5 30 May 2.01 7 01 201 2 01 Jun 21 64 21 64 32 42 32 42 JU! 5 97 5.97 895 8 96 Aug 6.89 6 89 10 33 10 33 Total 134.93 148 43 179 22 134.49 Taoie13.2 Reservoir Characteristics at Dead Description Minimum orawaown level Minimum river bee level Area ai deaa storage level Dead storage ma.s.i m a.s.i kni2 Mm3 Level QtSJiaJtl. ' 350.0 1320 0 67 aa 074 7 I N.J Water Works Design & Supervision Enterprise I Id Ajsnciabon with IntcrrcnUn?ntaJ Consultants and Technocrats Nt Lid.Aijn De des sa Im^ aciium Project jrteteorotogicat and Hydrological Aspects Table 13,3 Storage Reservoir Characteristics and Reliability Levels May SWT Description Unjf Ra/iabiWy fev&/ --------------------lj |...... ........ ................................ Phase I, Rot 1 Dam heighfyat spillway c.l) Spillway crest level 80 75% % 55% 90% 95% m 30.89 30.98 31.00 31,24 31.42 mast 1350.69 1350.90 1351 03 1351.24 1351 42 Area at normal waler level km? 70 797 71094 71424 71 952 72 546 uive storage Total storage Mrr? 67 3 74 4 02.3 95 1 109 4 MmJ 942 0 949 1 957 0 969 7 904.1 Spill over the spillway Mm1 Spill to Live storage 'ano Phase l Rot 2 1000 0 1799.0 1754 0 1703 0 1640 0 26 74 24,17 21 30 17.92 *4 90 Dam Aerghtfar spillway c.11 m 31,05 31.14 31.24 31 41 31.59 Spillway crest level m.a.s.t 1351 05 1351 14 1351 24 135* 41 1351.59 Area at normal water level kmz 71.325 71.622 71 952 72 513 73 107 Live storage Total storage Spill over me spillway Spill to live storage ratio Phase II. Rot 1 Mm2 30.0 07 1 95.1 108.6 123-1 MitT 954 6 9618 969 7 903.3 997 0 Mm1 1706 0 1705 0 1740 0 1 689 0 1626 0 22.34 20 49 10 31 15.55 13 21 Dam hejghtfat spillway c.l) m 31,14 31.22 31.33 31.5 31 66 Spillway cresl tovei Area at normal water level km? -351 14 1351.22 1351.33 1351 50 1351 68 71.622 71.806 72 249 72 010 73 404 Live storage Total stooge Spill Over the spillway Spill co live storage ratio Phase II Rot 2 Dam he/ghtfat spillway c.l) Spillway crest level Area at normal waler level Mm’ 87 1 93.5 1022 115.9 130 4 Mm3 961 0 968.1 976 9 990.5 1005 0 Mm5 1755.0 1 754 0 1 709.0 1658.D 1595 0 30 15 18 77 16.72 14 31 12 24 m 31.32 31.39 31.52 31,69 31.87 Live storage Totai storage Spill over the spillway Spill to live storage ratio m.a.s.; 1351.32 1351.39 1351 52 1351 69 1351 87 km3 72.215 72 447 72.B76 73 43? 74.031 Mm3 101 4 107.0 117 5 131.2 145 7 Mm3 976 1 901.7 992 1 1005 0 1020 4 Mm3 1739 0 1738.0 1693.0 >642 0 1579 0 17 14 16 24 1441 12 52 1004 L Water Works Design & Supervision Enterprise In Association with iDUrconunentii Consultants and Technocrats Prt Ltd.Arjo DedesKa irngaLlan Project Meteorological and Hydrological Aspects May 2007 14. DEDESSA SUB-BASIN MODELING 14.1 . Modeling for Arjo Dedessa dam for Ir rig ati on The simmialions discussed in previous secnons is lor a comprehensive analysis or Dedessa dam. which 15 the mam focus of the TOR A detailed Ms-Excei based model. using 1000 years of monthly data o1 inflows generatM synthetically were incorporated in (he vano-js runs to obtain the results as indicated in the Table 13 3 As can be seen from the water requirement available at Table 13 I. for the ultimate development phase II of the Dedessa dam, the optimal water abstraction is (or RoT 2. scenario cropping pattern Based on various combinations of the simulation runs which are ^ery exhaustive it could be stated that there could be two net phases of development The designs however need to be made for the phase II devetopmeni The fimneo up geometry of lhe reservoir at Dedessa dam for these two phases could as below This is lor lhe success or irrigation at B0% reliability The following abstracts are based on the results oi simulator considering only contemplated imgabon. phase 1 development of Deoessa dam Irrigation command Full reservoir tevei Storage at full reservoir □eaa storage level w Olume al Dead sLage iev& Live storage River bed ieve> Area al Dead storage tevet Area at full reservoirs level irrigation Demand 13.700 na 1351 14 m 961.8 Mm3 1350.00 m 874 67 Mm 07 lOMm’ 1320.00m 67 88 kmz 71 14km2 148 43Mm3 □ pot phase II dewelopmem of Dcoessa oam ■ irrigation command; 13 700 na ■ Full reservoir levei 1351 39 m ■ Storage aL full reservoir leve. 981 7 Mm1 * Dead storage level 1350 00m ■ Volumes at deao storage icvei 874 67 Mm Water Works Design & Supervision Enterprise In Associadon wlto In^r^nUnentxl Consult*^ and Technocrat Prt Ltd.Arjo Otdessa Itngiticn froject Meteorolo gical and Hydrological Aspects May 2007 • Lt-ve storage 137 OD Mm’ • River bea level 1320.00 m * Area at dead storage level 67 8S Km’ ■A rea al full reservoir level 72.07 kmz * Imgalion Demand 194 49Mm3 Thus boln ine above pnases satisfy contemplated irrigation with 60% reliability in me phase I and phase II. me cropping palierns envisageo are different However, for the linai design pi Deooesa dam. i| nps 1o oe based on phase if oevelgpmeni wiin ine above oam features il the development is for imgalwi only 14.2 The sub basin modeling When the aspect pf the development of Dedessa Sue oasm as a whote. including ihe present proposal of Dedessa dam. is laken for considerations, the need for the simuialion of the sub basm peoomes relevant The del ails end components of sucn sub basin simulation modeling could t>c for me following objectives ■ To explore the possibility of power generation at Deoessa aam Since only a small (ractior of the total inflow is io be jsea for irrigation, looking at power development options at the siie by raising the nam height rs an important consiaeranon ■ In such a scenano as above, thai is. full scale upper optimal development gi Dedessa dam, it becomes a necessity to check that this optimal water abstraction does not jeopardize future developments in the whoie ol the Deoessa sub-basin This requires basin modelling at a larger scale considering contemplated developments upstream ana downstream in this report simulation exercise has been carried out to aadress the first objective A tailor made sub basin modeling was cameo out by developing a Fortran source code named Aijosim to quicxty undertake simulation exercise ol vanous components with alternatives Water Works Design St Supervision Enterprise In Association with Lnienjuotlneatal Consultants ano Technocrats Pvl LtdArjo-Dedcssa Irrigation Projeti Mftteorologjcal and Hydrological Aspects _ _________ ________________ — 14.2.1 Power Generation in Dedessa Dam The Oedessa aam with its please II configur atio n. cou ld irrigate I3 700ha ar 80 n r c<iabiilF Since, left and ngnl bank mam canals take off fr om me dam., no incidental power can d^ generaced as such. Hence, power tJe^efopmenc options are sought by raising ihe da nr height .□ nave additional storage for separate power releases. The FRL for optimal phase II irrigation development is 1351 39 m. Two scenarios for Higher FRL values are considered with FRL ol 1353 m. and 1356 m For each FRL consiaered lour different power release options are taken up for the simulation as depicted tn Table 14 1 ft should be noted mat the given releases are total monthly releases for irrigation and hydropower That i-s, the given tola! releases less the monthty i rngarion requirement shall b e used 1 or p ower g enerauon I here will o e a s epara le outlet for power al the same level as thai of irrigation outlet, that •$. ai 1350 00m The reservoir charactensiics at the two FRLs considered for the simulation are Full Reservoir Level = 1353 m * Storage al lull reservoir level • Live storage • Deac storage level ■ Volume at aeao storage level ■ Area at full reservoir ievei Full Reservoir Level = 1356 m ■ Storage al full reservoir level ■ Live storage ■ Deaq storage .evei « Volume al deao storage ieve: ■ Area al full reservoir level 1093 51 Mrr3 217.33 Mm3 1350.00m 074 67 Mrr’ 77.83 krr.J 1341 16 Mm3 46B 49 Mm1 1350.00m 874 67 Mrr’ 87.85 km2 93 Water Works Design & Supervision Enterprise In Association with Imercontinenial Consultants and TKlmocrats Pvt Lid.ArjoDedessa IrrigaGoo Projett Meteorological and Hydrological Aspects Miy 2W7 The effective turbine center was fixed ai 1322 00 m elevation This or course. needs to oe toahzed 99 per ground wnditan ano dam head jot otherwise, omer kicaton based powerhouse aiw. me plant factor adopted in the bufc simulation runs te onfcy and with unrestricted instated c apacdy B ssed on a ctuai D Jdg&t ano power requirement a nalyvs o y Hydropower and Dam design engineer lhese msiaiied capacities could be changed or power generator, could ^e *esincted The results presented m the Hydrcnngic-ai simulator, are witn lhese assumptions on turbine center level and plant lacier However, ai deta led design singe with Lhese *irmed up Figures, die Sub ba&m models wuio be re-run in shon lime The power duration curves lor the vantius runs are shown m Figures '4 1 (al) 10 14 1 (b4| These iigures are useful io reckon the monthly power generation al venous exceeoanee prcoapiiily -evcls at proposed FRls of 1353 and 1356 With respect to annual energy production the resuiLs are prasented in (he Tahte 14 2 for Dedesse dam. This pfture of energy generation is after satisfying irrigation needs fully al B<]% reliability However the quanmm oF energy and power are of nol very detractive type. 14.2.2 Optimal Power Generation With FRl upto 1956, as seen above, ihougn imgalum h successful, the power generation scenario is no* atdadtvi i-ience thE Simula ton moaei Aniosim' was slightly recoded lor maxing simulators (or -ncreasea FRL considerations eno expionng inc possib'hly or power generation at a higher ievCi Though the exerc.ses are oeyond the scope of Che present TOR A Large numoer of runs ot Aqasim were undertaken under 3 different domains of preposilion These are Domain 1 seeping the power outlet at a lower lev&o! 1346 m and increasing tne FRL in stages, with rdnout monthly power release patterns Dmmd 2 keeping lhe power oullel at 1346 tn and increasing the FRu in Stages as aoovt Pul with model in bui'l decision support based power releases _______ D4 Waler Works Design & Supervision Enterprise io Ai'soclaiigri WLIh Ln-Lerro n Linen lsl! vOoSultaaH; mod TficUttOcrats Pvl Lid.Ar»ideua Lrrijaugu Project Meteorological and Hydrological Aspects Maj 3007 Domain 3; Keep.nS lhe power outlet * the «nw bevel » tnai of irrigation outlet [Q( course a separate power ouUei) and increasing (he FRL m stages. with decision support Jasttd powo releases b> ihe model Domain 1 Simulations a sei at 12 afferent runs were atunipted within th* FF?L ranges from 137G to 1376 m. and with drived menihiy power release pattern. Borneol the optical ones are i. With FRL 1370, the 97% power is 11.22 MW ■ Witn FRl 1372, the 97% power is 13.3QMW lii With FRL 1374 me 97% power :s B62MW Beyond FRL 1374 mere were no encouraging improvements m power generation Domain 2 Simulations These runs ipLaimg in 10 were made wtin decision suppon cased power releases in built in rhe model This obviously increases me power generation tor me sei or FRLs The opiifnai runs inpicaieo me following situation i Mh FRl 31 1372. ihe 97% pgwer is 1B.49MW ti Wuh FRL at i3?4 rhe firm power is *7 2QMW iii With FRL Ht 1376, me firm power is 17 90MW ,¥ With FRL at 13170, me firm power is T9.50 MW Domain 3 Simulations Here in aodiLcon to decision support power releases, the outlet was best ai 13S0W instead of 1346M aeopled in the previous domains This improved the Situalron Same ol the SBiieni model runs yielded the fo'.owing scenarios. 3 At FRL 1373 the iim-power at 97% 15 17MW li At FRl 1372m, the 97% cower is IB 1MW iu At FRl. t374-n, ine97% poweris IS &5MW n AL FRL 1376m, the 97% power is 20MW •>5 Water Works Design & Supervision Enterprise Ju luKiuteq tiOi biTsrctmiuieniiL Consuttatm and 'tatuKnu Pvt Ito.Arj&Dedtssi Irrigation Ptoj-ece ■’Meteorological and HydroiogicaUspectj^^ ______________ 14.2,3 Reduction Ln flows at Dedessa Sub’basin in «ilhar oi lhe cases covering 8 oms of simulation, that u no netrimer-tai effect on foe downstream f Lows ol Dedessa sub basm The maximum consumptive utilization is only for irrigation winch is only 104 49Mm annualty, as tne additional 3 releases made 1o* power are no: J for consumptive uses The power releases flows downsiream Thus a net reduction >r the subbasin Hows will be up La a datum ol *95mm . even wilhout accounting for any regeneration irom irngaiion The sub basin ol Deoessa contributes al its end annually to Atobay a auualum Pi i4,033t™r3 (6CEDM Master Plan study) This will gel: reduced to 13,838mm because ol me 1 proposed ago Deacssa project, whtfih is only a negligible reduction of ' 39% As such ine Ajjo Deoessa Dam proposal is not going fojjaOpfifdljK tne overall developments of the sub basin cons dwing vancms .deniiKec projects of me sub oasm 14.2.4 Conclusions The simulation runs cau.d be made tor runner difforem scenario. A1 1*hs stage, it coutc de satd that me optimal power generation would de wnh FF?l at 1378 m and with power ouifoi al 1350 m. The tail race rs assumed to pe at 1322 m in an the runs. With a plam factor pt 0 6. me installed capacity coula b e arouno 33MW H ybTDipgtcally. 1 ne simulations c an be porformeo lunner without any constraints, provided met there are no geoiogitai. gepthechniGsi, design environmental social arm tuber cansiramis The power generation at different reliaaifity paroemagas are shown tn the Figure 14.2 tor tne last run However io lorm jp power generation even at higher FRLs. a prefeasibilrty sluoy ifi required 1pr expionng the poss-bitiiies ot increasing the height ol aam and establishing tne technical feasibility ana economic viability tex generaltor ot hydro-power % Water Works Design & Supenlsfon Enterprise Ln Assoclzuort vnih [ntercanut»nul Ctmutmts udTectmoerru Pvt Lid.Ari^DeiSessalrrtgauon Project Meteorological and Hydrological Aspects Hay 2W7 Table 14.1: Total Monthly Release (Irrigation plus Power} options for various FRL values considered Options FRL = 1353 m FRL = 1356 m Optwrn 75 Mm' lor all months Twice ol monitiLy irrigation releases Ooitor 11 75 Mm - May to 3 September 6 50 Mm - 3 Ocl loAoril Opton Lil 75 Mm3-May to September £ 40 Mm} - Oci toApnl Option IV 150 Mm ' May lo August £ 40 Mm’ - Oct. Io Marcn 75 Mm m Sepi £ __Aprt __ __ _____ Three limes monthly irrigation Feieases 100 Mn?for all months 1 75 Mm - September to Apnl £ 100MCM - May. to August Table 14.2: Annual Energy generations at Oedessa dam for the various options FRL Release Annual Energy Production (GWti) at Exceedance Prohabilily Levels of Scenario Options Mean 50% 75% 90% 95% 97% -evei 1353 m 1 32 0 32 3 29 .B 27 3 25 2 220 II 260 28.9 26.5 24.3 22.7 20.5 111 253 25.9 25.5 22 9 21 3 196 IV 43 6 44 7 43 3 40 1 36 3 26 3 1356m 1 11-fi 12.0 11.9 n.a II 24 5 11.7 117 24.5 24.3 ill 24 0 540 23 8 23 6 55.2 50 6 SV 45 9 47 6 48 5 42 9 39 2 47 5 43.0 . 40 9 38 1 _____ -J Water Works Design & Supervision Enterprise In lUmnUon with Intetunttaienud CwvlLUts and Technocrats Pvt. LtdArja Dedesta Irngaifon Project Meteorological and Hydro logic al Aspects —A _______ _ _________________________ - ■ ■ ■ I I (0 1) Power duration curve for FRL = 1353m - Option I \3.2) Power duration curve for FRL = 1353m - Option H {a.3) Power duration curve for FRL = T353m - Option III Water Works Design & Supervision Enterprise In Association with tnismuiinemal Consultants and Technocrats Pvt LidIkdessa Irrigation Project Meteorological and Hydrological Aspects M^y 2007 p 4j Power duration curve For FRL - 1353m - Option IV (b.1) Power duration curve for FRL = 1356m - Opt*o,n i fb.2j Power duration curve for FRL = 1356m - Option H Water Works Design & Supervision Enterprise In Association with Intereenritienul Cnnsuitanu and Technocrats Kt LtdAfjo Ded«sa LrrtifitiQJi Ptujccl Meteorological and Hydrological Aspri rs liar (b.3} Power duration Curve for FRL = 1356m - Option 111 (b.4) Power duration curve for FRL ” 1356m - Option /V Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt UdArjoDeihtok IrrUJUhtt Project Meteorologic al and Hydrological Aspects 15. RECOMMENDATIONS ON TRAINING NEEDS Vir W 11 is very neartenmg development thM the water resources exploitation to* opitrna ’ ia towards economic stabihly is getting me major thru si m En^op** i/Vrfh pnase o< ac * soon me ncfi wer basins will be impounded in deferent storages associated wff - a r w >_ runoff the over schemes eilher tor irrigation or power or in a multi objective sens* As suet the present scenario the hydralog ica-i planning and design are in me usage Howeve w * me basins, in the near future, become stuffed with mar-y projects then Che real r me operated oi most projects will be me dire necessity JuCkc^al operation of a mum reservoir project system has a lol oi benefits in combating floods; tiding over drought reduction w waiwr osses and others However such real nme operation would require a complete Knowledge ih® hydrological sense) of the basin system, and hydrology and simulation techniques S'mylatKXi coupled wim optimization mooeis) Such a scenario oi real lime operation wiu nave to oe oacKeo up by flood forecasting networks, aovance prediction oi seasonal i-amta^ adequate telemetry (lor transfer oi data), oeoicated computers. telecommunication soft ware m addition to subject matter < hydrology,'simulation) software The personnel heading sue*" operations r a easin and those workrng in suer- a team need io be trained in the above mentioned asoect se as 10 u nderWte o peration which has i mmerse a du enrages h ence it is r eoommenoed t *a' expens on Hydrology and Hydrological modeling snoukl be identified for undergoing such trainings in InsiituUon&'unrversities m appropriate countries Though there could be many such institutes. the consultant leete for such multi system operation adequate expertise is available in countries like U SA and India, where many institutions, Jniversilies. River oasm authorities, and research stations could be identified for offering such trainings Such ironed personne' with expertise in hydrology will be able to hea<j luture nver basin authorities optimal "ea time operation of (he systems IN Water Works Design & Supervision Enterprise In AasDd&Uan with Inurtcaunequil runsuJUnw nnd TBrtuiocnrx Pn lmVjfl Mk\i [rrtfiriun Pro)^ r Meieorologlcal and Hydrohitlral H’^rii references *•» Admass Gebfjyehu 19&6 Region a- Ar ..tlys't ■» StF* A&Cw*♦ 1 m Ethiopia lUnpubbsned Oran Report August 1 -J Admasu GeMyertu 19S9 Regional dood Ffogue*-1- . Ana *’■ ■ ' ' ■ Technology. Bulletin Nd TRlTA VB' 1J|d J *' ‘ ** . *- m ***'■'' BCEOM 1999 Abbay River Pam Intonated Oi^'-JP",nr'' Matter p:an Pro.......................................... " m - - ■ *> Colled-on Site Investigation Survey ar.g Aral/S-S Section h ><cl'y.» Si x' <J > Volume in Water Resources Pan I Cl.matoingy and Part H ■ Hydr >iog.- B_t JV French Engineering Consultants in associjl nr with 1S4 i BRGM ERA (Ethiopian Reads Authonlyt. 2002 Drainage Design Martu.r Hnlrotoc* FrtMes D. 19?7 Flood ealimglipn 1or small East African n a calcnmen-t^ Pr&- - ? ■■ .■ JftgWu6wi nf Civii Engtneors, Pari 2 63 21 i 11 r 1 1 Gray. DM Editor in Chie< 1971 HadtTboo* on fho Punrjpw, ■.■» tw * Haar. CT 1977 Statistical Methods in Hydrology The (owa »«• Unewsity Aw HersfieW DM 1961 Estimating the probable maximum precip tai-or ASCE i-tydi D»v f No HyS 99 116 MataiHS N.C 196-J Probability OiSlrtthJ I K)n ot Low F tows Stalahcal Studies • Hvdm*xj- Geai Survey Prof Paper 4 34-A Snaw Eluabeth M igea Hydrology in Practice Iniemationat Van Nosttend Re*oho*C USSR (Ifnilen Slates Department oi the Inferior Bureau ol Reclamation 1. tgfrt i and aod Waiir Studies or the Blue Nile Basu- Ethiopia Appemjn lit ■ wydranjgy WAPCOS (Waler and Power Consultancy Services (India) Lid '■ 1990 Preliminary VS ate* Resources Development Masi er Plan lor Ethiopia Fmai Report V C4ume ill Anne- A H^njiuyv & Hydrogeology Acktis Ababa Waterworks Design & Supervise tnterprisp In Asiofiaiion Wilh InEtrtvnUneatal CtMvkutt urf TKhnocrw PvtV V M M N I M M M ri Arjo Deflessa Irrigation Project M^eorological and Hydrological Aspects ANNEXES Annex A Results obtained from the Meteorological Analysis -____ my 4Cir_ fclAi Al Eslimateg Mean Temperature al Arjo Dedcssa Project Area ■ in Cj /ear Jan Feb Marcn April Ma JuW Ju. l. y AA ... dy Sept Oct_ IMO* Dec 1961 222 2i a 24 7 24 Q 23 2 71 4 20 7 20 2 21 6 22 0 21 9 19 7 1962 200 21 8 24 9 22 5 23 2 21 0 EC 0 200 21 3 22 1 20 2 190 1963 21 7 23 2 24 3 163 159 21 & 2i i 20 6 21 4 2i 7 24 6 21 3 1964 21 7 229 25 4 24 6 23 7 21 5 26 4 20 4 21 4 22 0 2i 5 20 b 1965 21 5 8 24 8 24 8 23 5 21 6 2i 3 20 8 21 5 22 4 23 2 20.5 1966 22 7 23 6 25 3 24 fl 24 i 21 7 21 J 20 8 21 5 22 3 22 0 16 6 1967 195 22.5 25 i 24 a 23 7 21* 2 20 7 20 5 21 3 21 1 23 0 ia r 1968 19.9 224 23 6 245 24 1 21 6 21 6 21 i 2i 2 21 4 2i 2 196 1969 22 4 23 2 25 1 24 6 24.0 22 0 20 7 20 7 21 5 21 7 21 2 ’6 9 1970 21 5 229 25 0 24 9 24 3 Z2O 21 4 20 8 21 6 22 8 19? 10.2 1971 2i 8 20 4 23 9 24 7 23 7 21 a 21 0 19 9 2i i 22 4 2- r IB.2 i 1972 21 8 23 1 24.2 24 5 23 2 2i 0 21 & 21 3 2i 6 Z2 3 22 8 20 2 1973 22 7 22 6 25 8 26 8 24 1 2i B 21 3 £0 0 21 5 21 7 21 7 174 1974 21 2 23 3 25 3 23 9 23 9 21 B 20 8 21 3 21 3 21,2 19 1 19 0 1975 21 O 23 B 25.9 24 8 23 7 21 7 20 5 20 2 2i 3 21 9 20 4 10 9 1976 20 6 23 0 24 8 24 3 231 21 0 21 0 20 8 2i 6 22 4 22 5 197 1977 23 0 23 5 24.9 25 3 24 4 2 ■ 4 21 0 2i 3 2i 9 23 5 23 0 209 197B 21 1 22 6 26 1 25.6 23 8 219 20 9 21 2 21 1 22 3 20 9 20 4 1979 22.2 235 24 7 24 2 24 2 21 9 21.3 21 6 22 0 22 3 23 6 20 9 i960 22 3 24 ■ 26 1 25 H 24 4 22 3 2i 1 20 8 22.0 22 0 22 0 19 5 1981 22 * 22 6 262 25 1 24 7 22 3 20 6 21 1 2i 5 22 0 2i 6 192 19B2 227 223 23 8 24 9 23.5 21 9 21 2 20 7 2i 6 2i 8 23 0 20 6 1963 20 3 23 6 26 1 25 6 250 228 223 21 8 21 7 22 4 22 3 166 1984 2C6 20 6 25.4 20 2 24 5 2i 9 20 9 20 7 2i i 20 2 23 4 20 6 19B5 21.5 22 9 25 7 25 1 24 0 21 7 20 5 20 4 21 5 21 5 22 1 19 7 1966 21 5 24 7 23 9 24 5 24 6 22 0 2i 3 21 1 21.2 21 7 22 0 20 4 1907 2i a 23 0 25 4 25 1 24 2 22 6 22 2 21 6 21.9 231 22 7 202 19BS 22 4 24 5 25 1 25 8 25 3 22 5 21 3 21 6 21 9 22 5 20 6 10 0 1989 21 3 22 3 24 5 24 5 23.3 21-9 21 3 2i 6 21 7 22.0 71 9 21 5 1990 21 0 2’ 9 24 8 25 1 iaa 224 21 4 21 4 21 9 22 1 22 4 20 9 1991 23 0 23 6 25 1 25 1 24 6 226 21 3 20 8 22 0 21 4 21 d 16 2 1992 22 1 24 1 25 2 25? 24 6 22 3 21 1 21 3 21 8 22 7 1993 22 6 23 5 24 3 25 6 24 4 21 8 21 3 22 7 21 4 21 4 21 8 22 9 1994 1995 2< ??3 24 2 26.8 24 9 24 5 28 4 26 5 24 3 M3 2t 7 196 22.3 21.1 21 5 2i 8 33 i 215 22 1 22 3 22 0 23 3 2Q.0 1996 226 24 t 26 3 25.9 22 4 26 9 255 24 7 24 4 23 0 233 222 1997 23 4 21 9 21 7 21 8 22 4 23 i 22 3 223 23 2 23 4 22 4 22 3 23 ’ 22 4 22 0 20 2 1998 24 6 24 9 27 4 27 7 24 0 26 2 25 i 22 9 1999 2000 2001 2002 2003 2004 21 9 21 6 23 0 23 2 2i 9 24 2 22 A 26.2 26 3 22 9 26 5 26 6 24 3 26 0 26 4 23 6 269 25 9 24 5 284 25 7 24 2 262 26 5 24 9 25 5 255 25 8 25 8 25 6 22 B 2i 6 21 3 22 9 226 31 9 21 B 23.0 23 0 22 0 22 2 230 22 8 22 7 22 2 22 S 23 2 22 0 22 2 22 7 22.8 21 5 22 1 22 5 24 2 23 5 24 24 2 23 3 23 0 22 5 22 0 ’9 i 2i 0 19 8 23 5 20 0 23 6 21 6 £3 T 22 7 23 5 20 6 232 21 8 4 !03 Water Works Design & Supervision Enterprise In Association wUi Intercontinental Consultants and Technocrats Pn Lw.M® Better a Imgaiifiii Project MeteoroJpgira) a nd H) dro logical Aspern May 2007 A2: Estimaleti Minimum Temperature at Arjo Dedessa Project Area .in Cl Year Jan Fen Match A. nl MP. June July Aug Sepi Oc i NOV Dec iSfii 97 10 5 13 6 14 7 14 9 14 6 14 7 14 3 14 5 13 0 103 8 0 1962 08 W 5 13 9 130 15 0 14 3 14 2 14 2 14 4 130 9 S 7 7 1963 9 5 11 2 13 6 99 10 3 14 7 15 0 14 7 14 4 12 0 116 8 6 1964 95 11 1 142 150 153 *4 6 14 5 14 4 14 4 13 10 i 0 5 1965 94 106 *39 15 1 15 t 14 7 15 1 14 7 14 5 132 10 9 6 3 1966 9 9 11 4 14 2 151 15 5 14 0 15 2 14 7 4 5 132 to 3 76 1967 85 109 14 1 15 1 153 U 4 ■4 7 14 5 14 3 12 b 108 7 6 1966 a t ’08 13? 150 155 14 7 15 3 14 <4 14 3 12 6 100 8 0 1969 9 0 n 2 140 150 155 14 9 14 7 14 C 14 5 12 8 10 0 6 9 1570 94 11 1 14 0 152 t5 ? 149 15 2 14 7 14 5 13 5 9 3 7 4 1971 9 5 9 9 134 15 1 15 3 14 3 ■4 9 14 1 14 2 13 2 102 7 4 1972 94 n 2 13 5 15 2 14 9 14 3 ii 4 15 1 14 6 13 2 108 8 2 1973 99 10 9 14 4 16 3 15 5 14 8 5 1 14 7 14 5 ;2 a 10 2 7 1 1974 93 113 14 2 14 6 15 4 14 B 14 8 15 1 ’4 3 ’2 6 90 7 7 1975 92 31 4 14 5 15 1 153 14 6 14 6 14 3 14 4 12 9 96 7 7 1976 90 11 6 13 3 14 8 14 9 14 3 ‘4 9 14 7 14 5 13 2 106 80 1977 W 1 It 4 14 0 154 158 14 6 14 & 15 1 14 6 13 9 108 8 5 1978 92 11 Q 14 6 156 15 3 14 9 14 fl 150 14 2 13 2 9 fl 03 1979 i960 mi 90 10 9 14 7 153 16 0 15 1 ’4 6 14 ft 145 130 102 ra 1982 99 10 6 13 3 15 2 15 1 14 9 15 1 14 7 14 5 12 9 10.8 84 19B3 fl 9 11 4 14 6 156 16 1 15.5 156 15 5 14 6 13 2 10 5 76 19&4 90 10 0 142 16 0 ISO 14 9 14 8 14 6 14 2 ii 9 11 0 8 4 1965 94 11 1 14 4 153 15 5 14 0 ?46 144 14 S 12 7 10 4 80 1956 94 120 134 150 15 0 150 15 1 14 9 14 3 12 8 10 3 6.3 1987 95 11 1 t4? 15 3 156 154 is.a 15 3 14 a 136 107 82 198S 9 B 11 9 14 0 157 T0 3 153 15 1 153 14 0 13 3 9 7 76 1959 93 to a 138 149 iso 14 9 15 1 15 3 14 fl 13 0 10.3 8 fl 1990 97 106 13 9 15 3 12 0 152 152 152 14 8 13 Q 10 6 8 5 1991 10 I 11 4 14 0 153 159 15 4 15 1 14 7 148 12 6 10 l 7 4 1992 97 T1 5 14 1 104 i5 8 15 i 150 15 i 14 7 134 10 3 H 5 1993 99 11 4 136 156 157 15 4 15 2 15.2 14 7 13 S 102 7 9 1994 9.5 11 7 ISO 152 15.7 152 ISO 152 147 13 0 HQ B 1 1995 9B 11 9 140 16 2 16 3 15 7 15 5 15 6 150 13.6 11 0 90 1996 99 11 6 14 7 156 160 14 9 15 4 15.4 15 1 13 3 104 82 1997 10 2 108 15 1 156 »58 15 7 158 is a 155 142 11 0 93 1998 lOB 12 1 15 3 169 169 159 159 158 15 6 14 3 10 3 7 R ’999 9 6 11 0 14 7 16.0 16 i IS 5 154 15 1 154 13 9 99 B 0 2000 95 11 1 14 9 16 2 16 4 154 156 15 4 155 14 2 11 1 0 d 2001 10 1 ii fl 146 16 1 165 15 6 15 6 157 15 5 14 3 11 1 0 8 2002 io? 11 4 15 0 15 fl 16 6 15.5 16 1 15 7 154 138 109 9 2 2003 96 11 0 14 0 15 7 16 7 156 15 6 15 7 15 3 136 11 0 fl 4 2004 106 117 14 7 162 165 • 5 5 15 3 1ST 15 2 13 4 _HL? 88 9 7 11 4 13 fl 148 156 14 9 15 1 15 3 14 B 13 2 10 2 a 5 9 0 T1 7 14 6 15 7 150 ii 1 15.0 14 7 14 8 ’30 ID 3 79 Water Works Design & Supervision Enterprise Ln A^cciadcn wna Inicrrcntlnenul Consultants arm TKhnocniU pvi Ltd<Jj<* DfStwa Jrn;a LI on Project MetEprolaRicaJ anil Hydrological Aspects A3: Estimated Nanmurn Temperature st Arjo Drdessa Project Area (in QC} tear Jlari '*■ ''I Match ApflF Ma ■ June July Au9 serf (Jd NOt Uec 1961 34 7 33 0 35 6 33 6 31 7 26 6 26 7 - 26 1 1962 3T 2 33 0 35 8 3i 6 31 B 27 9 25 8 25 8 24 4 30 9 33 5 31 4 24 2 31 1 30 9 JU 4 7963 33 *j 35 2 34 0 22 8 2' 7 76 a 27 2 1964 33 <# 34 7 36 6 34 4 324 2B6 75 3 26 9 24 2 10 6 37 6 34 n 76 4 24 2 31 0 32 9 33 3 1965 33 6 33 1 35 7 34 7 32 1 28 8 ?7 5 26 9 24 3 31 5 35 5 3? 3 1967 304 34 1 362 34 7 32 4 282 26 7 26 5 "966 IS * 35 B 36 5 34 7 32 9 28 9 27 6 26 9 2J 4 31 4 33 6 30 i 24 1 29 5 35 1 29 9 1969 35 0 35 2 36 1 34 4 32 8 29 2 26 7 26 7 24 1 3C 6 32 4 2^0 1968 3i ■ 33 9 34 0 14 3 32 9 2B 8 ?? a 27 3 24 0 30 H 32 4 31 3 1970 33 6 34 6 36 0 34 0 33 3 29 2 27 6 26 9 21 4 32 11 30 2 29 1 1971 33 7 3i a 34 5 346 32 4 28 0 27 o 25 7 23 9 31 5 33 1 29 1 1972 336 35 0 ■U8 348 31 7 27 9 28 1 if 5 24 5 31 4 349 32 3 1973 35 4 34 7 37 1 37 5 32 9 7S II 27 5 26 9 24 4 30 5 32 1 27 8 19?4 33 1 35 3 36 5 33 5 32 7 28 9 26 fl 27 6 24 1 29 » 29 2 30 3 1975 32 8 35 7 37 3 34 B 32 4 28 9 26 5 26 1 24 2 30 0 31 2 30 2 1976 32 2 362 35 7 34 1 3* 5 27 9 27 0 26 9 24 4 31 5 34 6 3i 5 1977 15 3 35 6 35 9 35 4 33 4 2B S 27 1 276 24 8 33 0 352 33 4 t$?e 32 9 34 5 37 5 35 9 32 5 29 2 27 0 27 4 23 9 Ji 4 3t 9 32 6 1979 34 7 35 5 35 6 33 9 33 i 29 1 27 5 27 9 24 9 31 4 33 i 33 4 ™ 34 6 36 5 37.5 36 i 33 4 29 6 77 3 26 9 24 9 309 33.6 31 2 1961 35 0 34 2 37 8 35.1 33 8 29 6 26 6 27 2 24 4 30 9 331 30 6 1962 35 4 33 7 34 3 34 8 32 i 29 2 27 4 26 8 24 4 30 7 35 2 32 9 1963 31 7 35 7 37 0 35 B 342 30 4 28 8 28 2 74 5 31 5 34 1 29 8 1984 32 2 31 2 36 5 36 7 335 29 1 27 0 26 7 23 9 28 4 35 6 33 0 1985 33 6 34 0 37 0 35 2 328 28 9 26 5 264 24 3 30 3 33 8 31 4 1986 33 6 37 5 34 5 34 .1 33 6 29 3 27 5 27 3 24 0 00.5 33 6 32.6 '987 340 54 B 365 35 i 33 1 30 i 28 6 27 9 24 8 32 5 34 7 32 3 1986 35.0 37 2 36 i 36 1 34 8 299 27 5 279 24 8 31 7 31 5 30 1 1909 33 2 33 8 35 4 342 31 9 29 1 27 5 27 9 24 6 30 9 33 5 34 5 1990 32 8 33 2 35 7 35 2 25 4 29 8 27 6 27 7 24 8 31 1 34 J 33 4 1991 35 9 350 36 1 35 2 33 7 30 1 27 5 26 9 24 9 30 1 32 7 29 i 1992 34 5 36 5 36 3 35 3 33 6 29 6 27 2 27 5 24 7 32 0 33 3 34.0 1993 35 3 35 5 35 0 35 9 33 4 30 1 27 6 27 7 24 7 32 2 33 2 31 3 T994 33 7 36 7 38 6 34 8 33 3 297 27 3 27a 24 7 31 0 36 7 31 9 1995 340 37 2 38 0 37 2 346 30 8 28 2 28 5 25 3 32 3 86 6 35 5 1996 35 3 36 5 37 9 36 3 33 8 292 28 0 28.2 254 31 5 33 7 32 3 199? 365 33 9 368 35 7 33 4 30 8 28 7 28 9 26 3 33 8 M3 36 6 1998 38 4 37 7 39 4 38 B 35 8 31 1 28 9 28 9 26 i 34 i 33 6 30 5 1999 34 2 345 37 8 36 B 34 i 30 4 27 9 276 25 9 33 0 32 1 31 6 2000 33 7 34 J 38 2 37 3 34 B 30 1 28 3 28 2 26 0 13 7 36 0 33 2 2001 35 9 368 37 4 37 0 349 305 28 4 26 7 26 0 34 l 36 2 34 5 2002 36 2 35 7 38 7 36 2 35 2 30 3 29 3 28 7 25 8 32 8 35 3 36 2 2003 34 2 37 i 38 0 36 0 35 3 30 8 28 4 28 7 25 7 32 3 35 3 33 0 2004 37 9 36 6 37 H 37 2 35 0 304 27 8 28 6 25 5 3? 8 35 5 34 n I OS Water Works Design & Supervision Enterprise In Association wtui LniErcontmtnial CoiisuJianu and Technocrats Prt. LtdDflflrtu lirMLUjn Fir-|. J Meteorological and Kydralogtcal A'ipwte Ad EMimited Rtlitiwe HumidU ^ ji Arp , Prnj*tl Arn |*P P*^«n1 Year Jan Fe& Mjrm Apr>i L' ■; Jujf Au<| $*p1 pci . 1961 67 52 46 70 71 71 0/ 07 62 AJ Neu 60 O' rT■j. 1962 77 69 64 73 fl6 05 94 94 96 95 1963 45 72 6J a? 64 05 69 91 AJ 71 66 57 63 75 6? 83 BH 92 04 1965 67 53 50 68 69 76 63 65 84 02 *966 65 66 SO 71 73 76 M >: 05 04 1967 65 M 57 56 76 91 9-t 0M 92 05 00 M 07 as 73 75 B6 ‘4 60 6 J r 09 73 1966 55 66 54 66 75 Bi 00 85 69 BT 76 ft 1969 73 66 64 69 75 82 iW 3j K**l Bl- 1970 71 42 64 69 74 79 66 92 69 06 77 72 « 66 1971 SO 46 SO 64 76 01 67 07 07 197? M 65 56 70 74 79 69 65 06 50 1972 &5 59 57 66 76 01 62 flq 62 1974 49 53 SB 70 di 90 yfl 93 M 6? S3 77 72 75 63 63 1975 52 5m Si 70 74 »3 06 93 90 04 1976 55 55 57 79 Si 92 9t 91 91 73 93 ■6-6 62 1977 ft 6f. 56 57 66 11 0M 18 07 0fi as 74 1970 56 ST 56 64 75 77 67 06 A4 04 1979 SH 65 61 64 70 77 64 05 Bn 79 75 69 55 07 196(| SA 55 53 08 76 6i 86 B7 65 79 iBfil M 46 56 63 72 76 B6 06 63 a? t982 67 62 55 65 75 30 IB 90 90 07 75 77 06 65 79 1963 66 S3 Si 70 79 76 65 09 60 T9&4 W 49 47 61 76 SO 86 08 a-ti 74 tBB5 60 SO Si 67 76 SO 90 as 67 61 62 62 77 72 75 TO 1986 sa 60 57 60 73 65 67 B7 M 82 1907 SA 56 63 60 79 Bl 63 09 86 65 73 79 72 75 1966 73 64 « 62 75 82 90 91 93 67 1969 S3 61 60 75 73 79 9i 66 9i 84 73 82 66 55 1990 67 70 62 66 77 6i 90 90 91 80 1991 68 65 60 M 74 63 90 91 » 62 ao 75 71 75 1992 66 57 54 69 79 34 90 94 88 in 04 79 1993 65 63 56 75 eo 65 09 09 90 » 1994 SF 53 55 67 71 fi-6 06 98 0A 75 82 BO 69 72 1995 iXi sa $7 73 79 90 96 90 92 04 61 79 1996 73 43 63 ?3 ftD 63 69 07 01 1997 73 53 53 72 76 01 66 M 67 66 69 B9 70 80 1996 74 66 62 64 79 66 74 74 93 92 1999 61 48 53 65 76 60 90 69 92 2060 55 46 45 67 77 61 69 72 69 93 70 73 84 2001 67 57 5fl 69 67 M 61 90 91 92 69 06 2002 71 56 «2 64 71 61 d5 08 67 a-i 62 76 71 60 60 66 75 79 2003 65 ft 90 B9 90 @4 T ZUCM 46 59 55 70 ?3 76 31 07 09 69 91 76 70 Water Works Design & Supernal on Enterprise In AalocliUnn wlUl Ijiierromlnrolii CansultEnu ,lnd TxtmKnK P\i LtdArjo IMessi IrTiEn'foa rtnj^l Meteoroiogkai and llydrolot l f r * PPf fi: s . -— A5 EtUmaiM M*»n DiUy Sumion* OsMjtro<‘ it AJjo D*d»*w f r'Jlr ■1 *'•' yin hrVfliy.i tear Jan Feb Mar ch April 1961 83 ? 3 7 1 6.B 1962 6 7 b 9 82 7.8 1963 72 62 84 69 ■964 96 fl 3 J 7 60 1965 91 fl 3 86 55 M.bJ __Ju__n_e___■_J,_J7__ L p’ A kJ CM 5 90 4 66?5 4J. 93 6JO7 fi 1 6 5 7 6 7 5 9 1 92 X fl 9 7 4 73 44 38 5 8 6 0 9 T fl 3 1966 7 8 fl 2 7 1 fl 5 7 9 5 ? 4 K j a tfi 9 2 8 7 58 30 3 0 6 8 9 1 fl J 34 -1 5. S 1 9 7 4 1967 79 96 8 4 72 196B a r flO T 7 9 1 1969 fl. i 76 75 73 19?O 10 0 9 5 9 7 7 B 1971 9 2 76 7 5 7 3 7 5 6 I' 3 ’ 4 1 67 7 9 9 i 8 + 4 9 Sr 63 H 5 69 66 2 -1 J 2 5 7 6 5 7 fl 6 1 J? 4 1 62 7 « 94 SO 4 - J. 7 7 5 7 9 90 IOC fl 4 fl T 98 <3 76 1-0 10 t 8 3 a3 03 a3 83 B3 03 99 77 1973 9 5 fl 5 85 fl 4 10 1 7 3 32 4 1 1972 92 8 B 7 4 94 8 3 64 4 a a 80 A? T Tl ■ 'SI 95 9 5 90 1974 7 9 fl 1 7 3 6 7 9 1 59 4 B 4 fl 5 fl 56 D t 83 84 92 67 J 1 89 7 1 6 7 5 1 24 3 8 4 2 5 fl 7 8 r 5 65 1975 94 A3 75 64 1976 90 a 7 7fl fl 7 1977 62 S3 66 72 1976 94 5B 75 7 6 1979 S3 65 60 70 i960 6 1 53 1901 95 es 1962 74 60 1963 80 76 1984 B 1 9 9 7 4 5 fl 3 7 4 1 6 3 6 9 82 8 3 71 5D 3 1 i 6 4 1 7 5 69 7 1 3 7 4 1 5 2 6 ti 7 8 6 1 23 J a 55 6 El 5 fl 74 58 36 3 9 59 79 78 aa 46 59 79 58 37 4 5 26 65 96 ra 83 65 71 68 39 37 67 75 66 73 71 80 66 78 54 3 8 56 66 84 82 ai 89 66 60 47 4 3 70 10 1 86 8i 1985 B6 ?fi 75 68 64 59 28 31 58 76 67 78 1986 89 62 65 53 72 37 1987 ai 78 62 95 83 04 SB a3 56 70 33 49 40 41 42 74 74 78 94 B3 82 H0 1968 B4 76 27 4 9 55 a5 102 9i 1989 98 B4 73 72 96 73 37 5 1 S3 a3 B2 68 1990 92 49 63 33 54 46 37 39 59 96 B9 92 1991 B3 73 71 6B 54 85 43 62 9 1 92 09 74 1992 fi 7 69 62 7B 90 83 29 20 63 65 7 fl 75 1993 72 62 64 60 73 44 28 38 58 50 91 83 1994 96 fl 3 77 80 87 56 30 30 68 91 90 too 1995 91 S3 86 65 83 34 43 55 79 74 H4 8i 1996 ?a 62 71 85 76 53 42 38 60 9? 98 83 1997 79 96 B4 72 91 fl 1 49 5? 83 a5 7 fl 90 1998 fl 1 60 r? ai 88 80 23 37 57 65 W1 03 1999 «2 76 75 73 7 fl 6l 37 4 1 82 79 93 63 2000 100 96 97 7B 94 80 48 4 7 25 79 93 83 2001 92 7fl 75 73 76 61 37 4 1 62 79 83 93 2002 92 Bfl 74 94 a3 U 54 4 0 60 09 99 77 2003 05 B9 as a< 10 1 73 32 4 1 72 95 95 90 2004 79 fl 1 73 6? 91 59 4H 4 A 58 B fl 01 83 Water Works Design & Supervision Enterprise In Asswi.nU on wiLh Intercontinental ConsurtAnls itnd Twhtiomta Kt ltdAxji> [#■ -di JrzlxAil' d I'rnj' l M?U«rulo<kal and H»drolQrfi< al A-s^’1T A6 t5Um*|Crt Mean Dally ETo of Ar o DfUlisj Projad m*j 'tr ( i m innu'da, Year Jan Feb Macrt April Mb, 1M1 an 3*1 4 4 I 4 26 J 73 1962 J 23 3 "5 4 btl 4 32 4 4 ■ 1963 348 3 72 4 3 44 J ll'i 1964 3 95 4 18 4 65 4 66 4 . • J J j 3 49 . t»3 2 5 3 72 .1 €3 3 48 3 Sfr 1 f ; is 1 1 f>3 J 98 4 2* J 56 1 A.jg Sept (Xi Nov Ue*- j J 1 J 4 i 427 i tie. 24 J 4f 2 \ 1966 364 4 22 4 47 4 73 4 35 34 ill/ 3 J 7 4 31 J G9 3 15 1965 3HJ 4 J J 4 83 4 25 4 4 1 Z97 31 2 79 J 67 4 386 382 43 4 13 3 M 3 92 3 44 1967 3 45 4 44 4 77 4 45 4 6 3 95 3 i'j 32 4 22 4 .M J 72 1 46 I960 3 53 4 06 4 5 4 64 J 1 1969 3 7i 4 D6 4 S 4 43 1970 401 4 *5 5 08 4 56 J 76 T971 J 86 39 4 49 4 49 4 74 3 7i 2 Oj 2 9 3 Mr 159 4 06 3 4 3 W- ; 91 306 3 72 ■ 94 3 7 A 19 j fr 321 4 >i- 4 1 4 1 54 3 28 1972 3 66 4 34 45 5 03 4 34 3 55 J 39 31* 4 ’ ‘ 4 23 4 2 3 34 1973 301 4 3 4 87 4 42 491 3*4 2 81 j it. 4 5 tf.7 4 4 01 3 M j 49 2 93 3'Jt J r-U 4 J 75 3 29 1974 358 4 18 4 S3 4 24 46> 1975 3 82 4 27 4 66 4 34 4 09 3 51 3 3 3 29 J 62 4 07 1 95 3 35 3 3 2 73 ■ M 3 7 3 87 3 64 3 49 1976 3 73 4 38 4 65 4 75 4 02 36B 2 93 3 5 j ft ? 1 3 48 3 « 1977 34 3 85 4 34 4 40 4 24 t97B 3 65 362 4 64 4 7 4 39 3 46 2 9 3 1 3 H + 3 67 3 06 3 52 1979 3 36 3 S9 4 18 4 37 4 08 3 3fi 2 64 JP7 3 3 3 5 3 64 3 34 3 57 2 56 3 W 3 M 3 74 3 *9 3 23 1900 329 383 4 21 4 39i 4 32 1901 3 78 4 2$ 3.W 4 U 4 42 356 2 93 3 05 3 7 3 96 366 J 44 3 53 291 32 2 W 364 401 33 1982 36 3 74 4 53 4 32 4 13 3 77 2M ?98 3.67 3 86 4 • 3 a 1903 3.54 1984 3 58 4 14 4 55: 4 76 4 31 4 73 502 4 15 4 08 4 08 3 55 3 43 3 03 361 3 14 3 11 3 67 37 43 182 J 96 332 34* 1965 3 73 4 04 4 59 4 36 3 03 3 53 2 M 281 3 63 386 3M 337 1986 3 43 V04 4 31 4 03 4 22 304 2 85 1 oe 3 22 3 82 4 0* 346 1907 3 67 4 M 4 31 4 ?4 3 83 35 3 27 3 18 4 Dfl 4 3 83 3 96 1988 3 76 4 2 504 462 4 5M 3 78 2 71 3 34 3 59 4 17 4 02 3 48 1989 3 72 4 18 4 42 4 39 4 64 3 ft! 2 97 3 36 3 rr 4 06 3 74 3 24 1990 3 82 3 38 431 3 57 3 35 325 2 92 3 07 3 69 4 37 3 92 3 6? 1991 179 4 05 4 43 4 31 3 82 3 306 3 59 4 49 4 22 :i m 3M 1992 3 4? 3 94 4 71 4 82 4 85 3 63 2 73 2 59 3 78 37 3 81 J 38 1993 3 M 3 75 4 68 4 29 4 25 321 2 72 304 367 4 OT 3 »i 14 1994 3 B4 4 3 4 79 4 65 4 55 35 2 75 2 63 391 4 26 4 06 3 75 1995 392 4 34 4 9b 4 34 4 53 2 98 3 11 352 4 21 3 94 3 92 J » 1996 M4 429 4 57 4 88 4 37 3 35 3W 3 03 3 77 4 31 4 00 3*6 1997 3 77 4 43 4 85 4 46 4 65 40/ 323 3 46 4 41 4 32 39 3 85 1998 391 4 33 46 4 03 4 24 3 85 266 296 3 74 383 4 12 3 36 1999 3 68 4 t)J 4 67 4 57 4 36 3 63 2 96 3 M 3 63 4 11 37 3 42 2000 4 03 4 45 5 24 4 Jfl 4 86 4 15 3 31 3 35 4 19 4 16 3 92 35 2001 1 78 4 21 466 4 64 4 42 3 65 2 96 3 16 3 84 4 19 3 92 3 57 2002 4 4 39 4 75 5 U 4 59 3 71 3 46 3 4 *29 4 34 4 24 3M 2003 3 75 4 49 4 92 4 62 506 JBB 2 85 3 16 4 08 4 47 4 If 363 2004 1 84 4 28 4 5B 4 51 4 83 36 3 22 3 35 3 72 4J1 2 06 3 6i :A Water Works Design 4 Supervision Enterprise In A^nrlatlon with Intareor tinentaj CotuuJtvUa ind Tecbhocral* pst LidArjcDedcssa IrrlcatlOQ Project MfiEeonologicaJ and Hydrological Aspects A7: EXllmufldi Mtin Ma ntMy ETo pf ArJO DedesSff PrOJect Area (in mmJmonth? ------- — J _________ — - -—■ r ■ * Cafli Nov Dec I AnOiJsl Year Jan I May 2007 116 IDO 108 no 105 104 145 103 104 93 2 64 92 ° 139 128 nS 144 130 137 105 01 6 ?7 4 133 H2 109 112 104 99 124 127 122 117 144 119 110 150 140 140 104 84 3 85 6 ns 132 116 128 137 89 95 2 106 124 120 118 no 11& 107 114 110 H8 142 135 132 95 1 93 i 111 134 123 104 107 in ns ■124 It3 «2O 118 ail H8 116 105 ii9 104 102 li7 112 HO 111 116 124 148 133 143 110 97 7 103 127 125 111 107 114 140 139 127 111 814 69 9 108 114 140 133 133 107 90 i 94 8 124 157 137 14& 120 90 4 99 7 112 122 111 122 122 1-11 125 10? IDS 99 102 109 172 120 117 :20 123 106 igi 109 119 105 116 121 139 135 132 105 90 8 93 2 111 124 113 102 140 151 135 106 105 102 125 131 126 104 151 148 152 115 87 2 95 9 119 134 120 104 140 127 143 105 102 102 m 125 56 6 104 144 130- 127 99 84 7 75 7 95 120 109 108 135 144 143 125 111 90 8 94 8 105 115 104 105 135 132 104 90 98 113 120 116 109 141 136 107 130 131 126 -01 130 132 134 107 124 124 137 106 Ida 129 128 113 14’ 140 143 123 122 151 127 107 00 gi 9 909 90 i 92 3 tO6 97 4 942 106 116 114 100 95 3 94 5 99 2 925 94 90 9 1T1 m 109 123 86 5 113 HO 120 104 1D7 102 116 120 105 102 108 115 ns 966 116 133 120 103 107 n3 142 122 106 84 1 07 1 109 120 116 103 106 110 134 114 116 134 131 121 U2 131 91 3 382 95.6 95 5 118 120 119 105 101 98 122 124 ilb 107 123 117 110 156 145 142 113 115 117 137 132 144 n5 842 103 108 129 121 108 92 105 113 126 112 100 116 94 0 133 117 113 106 no :37 107 129 104 97 4 906 95 111 118 112 94 6 in 135 146 139 144 109 84 5 80 3 113 136 117 114 131 115 964 115 108 105 110 105 145 129 132 964 84 4 65 2 96 4 95 8 100 94 3 1T0 127 117 105 122 120 149 139 141 117 132 122 116 122 1,14 117 121 121 154 530 120 '24 ijl 142 153 149 ”47 140 135 126 113 134 144 IDS 29 4 1Q1 122 87 0 109 &4 107 122 110 111 134 123 107 132 134 117 119 146 132 115 07 6 91 9 112 119 124 ■ ’4 114 ’24 117 ns 124 123 145 137 135 1.09 924 963 H5 162 144 151 125 103 104 126 127 129 111 US 144 139 137 110 92 4 98 115 130 ns 147 l-§4 I 4? 111 107 106 129 135 116 Ti9 - 26 153 145 157 117 00 2 98 122 T39 127 126 120 142 135 150 108 100 104 112 130 61 7 1Q4 106 109 in no 112 112 i 1300 1303 1420 1410 1408 1444 1353 1369 1466 1366 14 66 1464 1346 1332 1375 1362 1359 1299 1343 1338 1 358 1401 1432 1349 1320 1412 1443 1408 1318 1411 1160 1355 1437 1439 1425 1505 1419 1402 1518 1429 1515 1498 1393 Water Works Design & Supervision Enterprise ’ In Association with iTicercoililniEntai Coasultanu and TBchnocrats Prt Ltd.^Tjottedessi Irrigation Project Meteorological and Hydrological Aspects A8;: Estimated Mean Monthly Rainfall at Arjo D&dessa project Area May ZOQj J*n March April May June July Au^ Sept Oct Nov Dec Annual 196? 156 0 96 3 21 7 172 172 140 ?20 ?20 111 5 151 D 12 1320 1968 □ 57 6 0 75 36 4 93 0 169 186 207 192 90 9? 21 7 145 1070 >969 37 7 35 9 53 7 140 121 144 159 212 IBS 56 39 7 39 0 1132 1970 2SJ 30 51 3 21 2 149 154 249 162 256 107 2 4 44 4 CM 1217 1971 T1 3 0 32 20 7 30 8 142 193 180 135 262 *88 2 32 3 14 1 1210 1972 156 11 1 15 89 T 53 166 106 157 170 49 48 69 9 24 1973 0 9 97 5 66 294 236 155 166 233 -43 50 82 12 2 5 77 l9?4 3B 7 798 31 0 5 14 2fl7 205 242 166 212 72 7£ 4 02 16 7 1975 23.5 55 1 21 1 60 4 116 124 189 159 -41 131 3 11 5 12 5 930.6 1075 1292 1045 1976 23 7 16 2 90 3 55 B 154 154 192 215 273 aa 6b 36 5 37 1303 T37B 3 3 5 66 5 103 122 154 206 206 1BI 122 6 0 50 12 5 11B1 1979 15 6 8 E9 17 25 6 97 5 202 235 159 154 64 94 312 12 5 1024 19BD 15 6 178 57.3 110 164 100 136 176 246 49 87 20 7 0 1 no *961 156 8 23 27 6 35.6 149 213 296 270 177 1139 57 2 0 1362 1964 156 0 31 6 69 a 234 249 4-43 19B 230 0 716 26 e 5 77 1514 iws 2 79 0 123 ros 257 341 242 212 315 48.2 32 5 37 7 1607 1966 □ 39 2 46 9 56 4 37 5 3T5 274 244 191 iwa 359 0 46 1345 1967 2 89 172 886 79 9 123 2B2 488 328 183 1164 42 3 34 3 1785 1988 14 1 42 7 74 3 15 3 335 325 177 297 343 259.9 154 3.87 1903 ’989 26 5 26 7 76 3 106 245 284 316 332 297 109.3 61 3 47 1 20DB 1990 6 77 37 B 50 4 B3.3 906 436 228 319 241 73 69 33 4 3 12 1607 1991 26 4 7 9: 682 74 4 139 106 364 309 222 98 59 35 13 1464 1992 24 8 32 8 106 105 222 225 267 291 250 104 7 53 5 156 1697 199 J 1 04 31 695 100 213 313 217 347 166 149 4 2.03 0 1649 112 i 15 20 i 539 127 227 255 228 279 8 467 13 7 0 1223 1995 a 22 9 75.5 103 222 195 229 3T0 2?o 85 45 11 2 22 3 1563 1996 45 5 19 1 162 71 7 330 225 245 197 215 74 57 44 6 7 56 1645 1997 39 6 0 97 566 139 293 814 205 291 234 213 40 4 2 54 1830 199B 13 84 01 1 15.2 162 280 264 272 239 2359 67 2 1 04 1638 1999 31 7 291 15 92 3 393 427 257 239 309 197 3 8.89 42 1 2014 2000 0 0 3 69 105 195 345 222 260 274 255 344 7 39 1702 200’ 0 32 65 5 50 3 327 346 298 292 312 206 3 19 3 24 1 1903 2002 177 2 19 39 7 42 2 106 252 2?4 153 224 59 11 1 8* 531 1226 2W3 5W 63 5 117 121 58 9 358 232 300 155 51 S3 11 5 t 86 1466 ZOC-a 4 96 2 ' 61 2 5! 5 1.50 353 325 243 249 193 9 40 7 13 i 1689 Av*f>Q4 15 3 Tfi 4 53 6 69 5 T80 8 243.0 245 9 238.3 228 6 715,5 31 4 127 1452 9 cv 0.85 3 96 0 68 0 55 fl. 49 0 37 0 31 0 25 0.24 0.591 0.9 1 13 0.203 SMW 0 62 0.78 0 74 0 1 062 0 38 7 44 o.a? Q.17 0 635 2.31 1 48 0 26 Mu 45 5 576 161 7 TJ9 9 392 7 437 6 487 6 345 6 34J1 259 9 150 7 53 1 2014.5 Mln GO 0.0 08 5 1 37 5 100 3 336.2 135.3 14* 3 J-5 0 6 00. 990.6 Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt. Ltd I ioArjo Odessa Irrigatloa Project MeteoroloEica^ndHytlrolDg'Ica^spects A9: Estimated Mean HaN-Monthly Ralnfal at the Project Area (in mm/hrl May 2007 1.1 1 1 * 21 22 3 1 JZ 4 1 42 5 1 52 81 02 7 1 7 2 8 1 fl 2 9 1 92 JO 10 ff 7 I? T2 I *2 Fof#/ Year 1967 79 7 79 □ 0 22 4 739 0 21 7 752 9697 112 60 8 68 4 71 7 110 110 132 07 7 11D 1 92 75 7 75 0 12 0 1320 1966 I0 0 57 3 0 29 0 0 75 1 27 35 i 31 02 8 81 4 67 4 82 5 104 12 ■ 86 1 76 5 115 76 6 14 2 0 71 7 in 3 4 25 1070 1969 ?B 1 11 6 14 7 21 2 376 16 1 6 75 133 18 103 1 72 3 71 9 55 2 103 106 106 83 6 81 7 38 20 4 3 46 3 92 0 0 1132 1970 2 1 27 1 7 27 227 23 6 27 7 1 73 195 34 3 114 3 49 4 104 127 4 122 81 7 79 8 94 4 162 5U 57 3 4 44 0 0 4 04 1217 1971 ' H 0 2? 0 32 0 4 62 16 304 0 46 42 1 99 06 62 2 131 63 4 116 81 4 73 9 125 137 104 64 3 26 6 5 48 3 17 11 1210 1972 78 7 79 4 31 6 04 0 15 36 5 52 6 25 5 27 53 70 1 07 9 872 99 89 7 67 2 94 2 758 25 7 23 6 61 3 7 69 0 9 74 990 6 1973 0 0 9 97 0 0 5 65 25 4 4 04 140 96 39 962 58 9 91 0 94 7 108 125 70 8 64 1 57 1 1 73 17? 0 0 5 77 1075 1974 30 6 0 12 2 26 5 72 199 11 9 0 29 4 05 168 98 87 102 103 119 5 123 101 67 5 102 110 44 4 28 3 0 4 62 4 62 12 1 1292 1975 o 23 5 47 7 7 4 0 69 20 4 5 14 55 2 67 5 40 89 80 8 43 3 75 2 113 62 1 96 9 92 5 48 R 86 9 444 11 5 0 6 06 6 46 1045 1976 23 7 0 103 5 69 57 9 32 4 32 2 23 5 76 8 74 81 7? 01 6 102 9 89 1 51 9 163 t9B 74 2 40 1 46 6 32 398 2 89 2 48 1303 1976 3 0 35 0 564 10 1 124 909 49 1 73 14 87 8 60 79 7 12? 71 2 134 84 8 965 72 505 058 0 6 06 6 46 1181 1979 78 7 79 6 89 0 0 46 16 5 11 6 14 572 40 35 99 6 102 145 903 85 5 73 6 97 2 57 404 24 5 156 15 6 6U6 6 46 1024 1®W 76 7 79 0 69 6 69 27 7 29 6 28 6 69 8 64 2 100 3 41 6 58 7 65 6 70 6 99 78 5 130 109 26 3 23 5 11 9 16 9 0 0 1110 1963 7 0 7 79 7 90 0 25 16 7 0 89 20 7 14 9 54 3 94 53 69 7 123 168 1 128 134 136 89 9 8 b 7 78 7 35 2 44 2 13 0 0 1362 1904 78 7 79 0 0 4 73 76 9 17 3 52 5 53 9 160 3 138 111 232 6 211 51 A 147 66 7 163 7 16 1 56 15 2 11 6 4 96 081 1514 raes 0 3 2 49 0 0 1 5 10 8 57 5 47 8 121 136 6 16B 173 94 1 146 62 6 130 160 155 37 2 11 24 9 7 58 36 9 0 81 1607 1966 0 0 2 75 36 4 15 2 31 7 28 1 28 3 124 36 22 195 119 147 6 127 110 134 114 77 1 as 18 9 20? 7 60 0 23 0 23 1345 1967 0 2 69 0 17 2 49 1 40 5 6 93 729 192 104 3 158 124 224 5 263 215 112 116 66 0 01 4 35 31 2 11 343 D 1785 i960 94 4 73 2 66 40 57 173 098 14 3 145 190 2 172 154 75 i 102 175 122 179 164 155 tO4 154 0 0 3 87 1903 1989 16 6 7 03 26 0 7 43 9 32 5 65 3 42 7 148 96 74 182 102 208 4 107 186 145 194 t(]4 915 97 8 29 5 31 6 190 27 3 2O0B 1990 0 8 77 13 1 24 7 21 6 28 8 0 83 3 60 3 303 253 185 123 1 105 IO8 211 98 1 143 53 4 20 4 32 4 1 03 3 12 0 1607 1991 14? 12 2 0 7 91 37 6 306 1 27 732 89 9 49 04 133 93 1 195 1 169 1?9 131 144 77 9 97 3 1 27 IOS 24 5 12 7 0 20 1464 ’992 0 24 6 177 152 252 606 3 34 102 152 70 12 82 1 143 161 3 106 159 131 102 148 81 4 23 3 79 24 6 1 15 14 7 1697 : _____________ 111 Water Works Design & Supervision Enterprise Id Association wlLh Intercontinental Caasultaals and Technocrats Pvt Ltd.Arjo D«d*»a lrriEUlJon Project Meteorological and Hydrological Aspects mi 2007 | —r 5 1 1 2 2 1 2.2 3 1 3 2 4 1 4 2 5 f 52 *7 fi 2 7 1 7.2 f.T 02 9 .1 9 2 10 M | ■ ■< ” —I ■ | 10 JI 1 TJ 12 1 12 Year ms 0 1 CM 6 64 24 4 3 06 66 4 63 6 36 6 93 7 119 7 06 2 227 797 137 149 197 RM 61 9 03 9 65 5 1 39 0 65 0 D Tott) 1609 11 2 0 0 1 15 1 3 IBS 29 2 24 7 55 71 64 105 122 109 7 145 116 111 106 112 7 24 1 23 9 52 4 16 0 0 1223 0 0 56 17 3 0 75 5052 109 116 105 9 63 4 131 123 9 105 177 133 125 154 40 0 45 7 5 95 5 3 1 96 20 4 1563 1995 92 36 3 4 09 15 Z8 0 62 9 26 6 45 1 146 192 4 159 66 1 34 7 160 '00 966 932 122 582 16 4 fl 40 36 1 0 69 6 07 1645 1996 2 1 37 5 0 0 97 20 1 28 5 72 0 66 6 71 7 2?1 5 15? 161 70 6 127 165 126 140 05 0 119 94 2 25 3 15 1 0 06 7 40| 1830 199 7 1990 11 2 1 B4 1 94 6 46 24 6 56 5 6 89 6 33 69 7 92 10 142 130 141 7 122 131 142 110 121 92 9 143 62 3 4 92 0 IM 1638 1999 2fl 3 3 36 0 291 0 15 19 733 227 166 209 217 99 2 150 141 902 146 162 140 48 9 B 89 0 26 6 15 5 2014 2030 0 0 0 0 2 31 1 39 28 4 76 2 76 9 118 6 215 129 994 123 149 112 139 135 160 87 1 25 2 9 15 2 89 4 5 1702 2001 0 0 23 7 0 3 1 24 64 3 36 9 23 3 230 6 122 224 1163 100 126 155 187 124 96 4 110 7 27 12 7 14 4 9 75 1903 2002 12 5 5 19 0 2 19 0 37 31 3 37 7 4 49 19 6 06 64 139 114 156 4 110 51 7 102 95 4 129 35 3 23 8 0 1 84 3 29 49 8 1226 2003 2 3 64 17 8 35 7 39 ? ?7 6 68 8 52 3 20 3 38 67 165 193 127 5 105 133 Iflft 059 60 1 23 7 27 9 6 64 4 91 1 4 0 46 1466 2004 02 4 76 1 4 07 106 506 97 41 fl 28 5 121 9 146 204 256 7 69 6 91 1 152 132 117 inn 25 T 11 3 29 4 9 24 3 88 1689 Avtr«g« >5 7# 0 0 9 0 21? 0 33 fl 22 7 46 7 78 2 1028 1F90 12J 2 122 0 123 9 117 121 fi 1200 roa 5 73 7 41 fl 19 7 1 r 8 6 f 66 14529 GV F ftf J 23 14$ f 21 1 03 0 74 0 95 0 72 068 G5f F 0 46 041 0 425 031 0 J6 0 29 0 3 0 32 0.50 0 tfb 0 94 1 76 f 57 15 0 209 ShtfMa 1 27 1 82 2 47 1 27 0 95 0 83 0 95 0 63 0 94 0 64 041 057 1 039 f 64 0 36 0 4Z 0 72 0 1 0 63 TIT 1 4? 261 2 15 29 0 20 Mftk 30 6 3 7 5 57 3 40 0 78 8 82 9 72 8 133 1 226 7 230 8 252 9 226 0 256 7 263 216 210 9 198 4 164 T&8 3 143 0 75 7 75 0 36 9 49 8 2Q14 5 M.n GO 00 00 00 00 08 00 05 f 2 27 5 i J 3 43 3 55 2 69 6 51 7 67 2 66 7 48 6 72 12 0.0 0 0 0 0 0 0 990 6 A Water Works Design & Supervision Enterprise la Association wilb Intercontinental Consultants and Tech nor rats Pvt LtrttatuilrriEaEJM fayed Meteorological and Hydrological Aspects Annex S Results obtained from 1 he Hydrological Analysis 01 Eshmaied Monthly Flows 41 Arjo Dodessa Dam Site I'm? mHqta- of) __________ . ------------------------------------------------ _ ___ u-__ Ytir . luar ~Ia<X May Jun Jul A**fl S*p __lpcl 30 ”4 26 02 25 73 63 61 49 78 207 7 7515 972 5 KX) Nov -D,c 2914 101* ’962 34 ‘8 SB 1947 5 073 21.39 157? 397 6 540 6 7DO 8 512 2 64 92 31.95 22 72 12 3 12 26 30 S6 111 6 235 3 429 5 626 3 622 6 223 9 mS 97.23 AnOU»l I 2*25 2736 1%4 7 542 24 32 17 86 2*21 4169 lfi-7 670 784 4 705 4 621 4 307 42 03 3413 1965 33 05 16 1 11 24 34 56 21 07 12? 1 532? 633 6 410 3 573 5 194 6 90 12 | 2»M 1966 42 41 40.3 39 6' 5361 <7 41 134 3 M7 5 6S4 6 ?26 3 49 32 25 34 >1 62 2372 '967 5 656 5 354 15.57 14 73 1924 82 14 452 6 764 7 719 5 634.6 40<14 '-20.1 3236 1965 30 4 29 71 46.01 2U.M 55 55 252 9 607 657 565 3 174.2 53 41 24 41 2726 WO 20 38 5351 9 245 24 2’ 34 36 209 3 593 4 635 7 673 2 121 1 110 2 35*6 2472 l*7i 221 10 44 7 454 9Q19 40 6 175 5 525.6 704 6 566 4 450 3 ’44 3 60 15 2763 1972 313 16 92 1343 25 78 42.79 BSfii 512.9 746 2 430 7 125 4 7109 29 96 2134 1973 T5 44 7121 3 221 4 586 8Z.W 181 5 156 2 533 539 1 354 5 90 45 37 246* 1974 ?1 79 10 31 9 487 6 56 1 71 15 19C 409.5 7706 195 6 43 73 72 32 27 9 1069 19T9 10 27 7 8(H 5 815 15 56 35 18 $4 19 340 6 497 5 37i 157 1 5707 25.13 1619 i960 10 73 9 737 6 439 45 56 144 9 364 1 544 3 777 74 5 235.5 6 2 7 1 52 8 3W5 1961 4775 27 57 28 73 25 54 40.74 36 7i 412.6 633 540 6 315 2 19 85 7 ’38 2139 *902 36 71 1J2 1963 13.95 34 68 180 3 451 6 57i 2 414.6 455 6 107* 53 96 2156 1993 25 9 2013 23 4 ’6 68 39 8 ■ 1 i 5 36i 4 687 668 2 6i7 6 242 5 69 26 2924 i9B4 23 01 ’Ofii a I4« 8 954 2i 59 134 7 449 2 4012 311 8 78 36 12 69 4 808 1463 190-5 7'52 3 46? 1 775 3.54 47.33 523 1 240 559 504 1 155 7 46 31 25.72 1?64 19M 104J 6-352 11 02 9 W3 9 685 86 35 254 9 2W 2 43B4 132 9 50 52 28 15 1369 1907 7 756 3 775 8 501 12.5 27 62 157 2 412 8 633 402 9 23 1 4 97 4 7 38 7 2034 1W 2*16 17 49 14 79 5 553 28 06 203 6 35*5 689 1 905.1 315 2 ’14 9 46 11 Z71» 19*9 19® 25 u B4 '357 24 24 2058 4763 174 3 30 H 851 3 3152 66 16 7031 17M J'93 19’I 23i 9 44.03 3'9i 114 4 219 3 1043 669 7 280.5 46 23 23 01 2546 199 * 16 3 12 32 ’0 51 18 94 44 17 113 4 517.4 954 2 456 9 3109 29 61 2i 7 "992 1462 5 23 9435 14 95 4? 55 116 8 2351 497 2 336 1 482.9 99 78 4'9 2547 1905 TM3 254 ’7 72 16 74 3956 79 B6 226.9 383 1 698 7 377 8 243 8 107 6 36 17 2253 199* 23 32 12 45 1062 11 34 45.32 160 1 3413 736 3 514 93 66 4135 31139 san 1995 12 15 7 787 1015 14 M 29 04 6C 34 1438 343 1 391 9356 38 44 82 8 1124 1990 2925 16 4* 26 36 ?1M 1G7’ 271 3 462 2 515.2 358 22S 1 7187 49 76 2157 2003 50 5 37 M 45 32 41 35 97 36 29i 4 4731 830 3 M2 2 403 8 130 5 63 78 796* 2W2 5909 36 35 37 91 4585 35 1 127 292 1 356 4 348 1 2 7004 47 88 ISSG 2003 33 56 2305 3»53 53 75 36 41 87 39 347.2 393.2 540 6 3i5 2 M 27 46 :1 203* 312 25 55 20 78 20 73 49 47 1468 336 3 385 2 384 9 322 3 85 26 *6'1 1055 WatEr Works Design & Supervision Enterprise Is 43Sficiluqii iiiih lniKt€£nl! []£3i:3j Cdiu-uIiaqes n.n3 fec&uscfm Pvt LtdArjfl DrJtsta ImeauoB Project Meteorological and Hydro logteal Aspects B? Regional monthly coefficient o( variation* (C V] ■ SWw? roar Jar? Feb Mur April May June- July: Aug May — 1140Q1 35 0 51 0.57 O6£ 114014 20 0 47 0 46 0 *8 114005 23 0 26 041 033 114004 22 on 0 42 045 1T4O03 21 0 51 0 63 0 57 91000 30 D.66 13 D7 0 6-3 052 0 45 0 35 0 3 0 56 0 69 0 53 0 27 0 33 043 D.6 0 47 0.2 0 16 0 55 0 56 D43 0 57 0 36 o n 066 0 56 0 35 0.25 Dec 0 33 0 67 0 62 0 59 0 26 0 56 0 31 0.53 0 25 0 44 0.3 0 34 0 43 0.64 0 35 033 0 35 0 56 0 46 0 55 9 1012 35 0 6i 0 49 0 76 0 49 0 57 0 42 03 0 29 0 32 0 52 03 0 56 06 0 61 0 4€ 3 29- 0 32 O2S OM 1 0.86 Hl OimnHJkl mnotnlu t&efflCiftflt SkC^neSS Srawi- t«ar jsn FcO Mar April Ma/ June Joly 114001 35 5 63 0 74 1 07 0.94 1 63 0 B9 0.13 So/j Dsr 0 04 0 25 0 99 1 37 096 114014 20 1 35 0 31 0.47 O.Bi 0 65 103 0 5 0.93 0 69 067 26 1 96 114005 23 0 33 1 4G 0 59 -0 1 2 IB 1 54 0 0? □ 45 0 B' 0 42 0 52 i 09 91006 30 2 73 029 3.26 0 77 1 14 0 Bl 0 17 1 14 1 13 0 77 3 14 2 65 91012 35 3 17 4 9* 1 22 1 5 2 34 1 15 0 <3 0 94 DOS 1 6 286 2 79 B4 1$ Regional monthly coefficient of correlations (Rj Slafw? rear Jan F®0 Mar M?y Junto- Jufy Ajy Sey. Oct a/om- l>\j 1 ’.4001 35 .0 1 0 63 0 09 C 59 0.3 114014 2C 036 0.5 0 77 D56 0 62 114005 23 0S« 0 5 0 35 0.3 064 t14QQ4 22 Ofl 0 52 0 2i 0 52 06 ’14003 21 u 3a 03 0 18 0 52 0<5 91006 38 o:? 0 33 037 027 0 53 0.76 0 45 0 53 0 44 0 45 0 74 0 78 0 BI D*S 054 0 28 >0 04 0 65 0 7B 0 3B 048 0 60 OB 0 B3 0.25 01E 9.68 0 56 0 69 0 6‘ 077 037 014 Q 73 0 66 0 56 0 5B 082 056 0 1 0.59 0 54 0.55 046 0*5 0 77 0 62 91012 35 012 0&3 0 72 ■2 48 041 0 72 0 53 041 0 48 03i 0 44 0 65 1 j 1.4 Water Works Design & Supervision Enterprise Id Association with TncertoDtinunal CoMiiluteis and Technocrats Pvt. Ltd. 1 8Mo Dsdeua Irdzidcn Pjojch jteteorotogical and Hydrological Aspects May L:LMT7 85 Standardized probability weighted moments Station Name of Station ------- -- j-— Location Area Record _________ PWMs —— Deg N. Deg E |km2l Lwnflh.N Wim _! fflm___________________ 1 114001 Dedessa near Arjo B41 3G 25 9981 29 0 40739 0 243171 2 114014 Upper Dedessa near Demoi 6 02 36 28 1806 15 0 420504 0.262951 3 1140Q5 Qabana near Abasina 9 02 36.03 2881 16 0 414042 0 253945 4 91008 Gilge< Ghibe 7 45 37 11 2966 37 0 400025 0 240847 5 91012 Gojeo near She De 7 25 36 2 3 3494 34 0.408619 0240091 6 114007 7 1140Q4 Angar Cutin near Neqemte Wanna near Neqemte e S3 i 8 114003 Sitfa near Neqemle 9 115008 Aleltu al Nejo 10 101001 Sor at Meiu 11 91013 Ghlbe-Limu near Limu 12 91001 Great Grube near Abell WetgJlteo Average B 52 35.45 951 20 0 416527 930 35 3 155 7 0 400261 a 19 35.36 1622 17 0 401323 a 35 37 13 663 TO 0 425296 a 14 37 15 15460 19 0.424754 — 1975 20 0421145 0.254033 36 47 844 21 0 419805 0.254029 0.251324 0 2475B2 0 244655 0 261749 0 250656 255 JZ471964 0 250375 Water Works Design & Supervision Enterprise Id Association with Intercontinental ConsulUnis anti Technocrats Pre LtdAJJ* Qttftssi Ijflpncn Project Meteorological and Hydro logical Aspects B6 Mcjq Monthly Total (Suspended and Bed) Sediment Loa d at Arp Deduct Dam Site (In 1000 m } Hay 1 Mar Jin Frb Mirth Apr>l May JuAff July Aug 5#p Otl Hoy Dec Annuli >9fil 2 11 1 75 1.2? T?3~ 3 IT 33* ji5 S23 4 76 372 32.3 15 3 1781 2H 0&4 051 1 C7 3 18 224 114 216 319 189 6.92 2 41 878.9 1 3 047 0 39 1 6 11 3 40 8 129 403 264 504 i$5 14 3 932.5 1964 17a 1 32 0 71 1 07 2 34 236 262 3?0 322 387 i& 7 3 74 1 397 2 3? 0 72 D 34 1.91 0 79 14 3 162 263 135 22? 40 1 12 7 880.5 1966 354 313 2 54 3 56 2 98 22 4 190 277 338 102 40 8 9 14 995.4 1967 064 0 57 057 0 45 3 18 22 4 140 358 333 352 71 4 20 1 1300 1966 5 73 2 22 0 52 0 22 2 26 2.27 123 265 290 102 104 2.9? 815 6 19B9 ?£7 1 92 3.22 1 42 3 71 46 1 224 427 205 102 5 13 1 78 1970 1 09 0 75 0 4 023 1 72 338 216 246 205 102 16 1 285 10Z4 82fl.7 I9?i 1 25 0 36 0 18 0 22 2 25 25.5 176 315 220 154 36 9 «&4 MB 3 W 2.17 o w 045 1 2 2 44 B.09 171 342 146 199 6 2 IS 704 9 1973 07 02 0 05 0 08 7 04 269 123 246 425 105 11 8 3 05 9*9$ 197* i 22 0 D28 0 13 5.51 29 119 360 MS 102 6 23 i 94 (39 J 1979 i 9i i 29 0 65 0 59 1 79 9 43 88 9 179 115 2B S 5 63 1 64 434.5 19M 0.39 0 3 D 15 3 41 172 82 8 2H 365 352 54 6 6 55 5 39 1098 1982 2.69 096 0.83 0 45 1 74 26 7 140 223 138 157 15.5 5 58 711.7 1983 1 61 1 03 1 09 06t 2 W 12.3 97 7 300 296 3 39 29$ 8 32 1089 1964 i 33 0 3S 02 0.14 0 82 15 7 138 127 67.3 9 39 15 5 524 402.1 1945 52 0 05 0 02 02 2 6? 14.5 65 216 100 28 2 4 31 1 71 520.8 1966 0.35 a 15 0 33 026 0 23 8 21 68 3 76 151 21 9 155 5 24 34^ IM? 0 23 007 0 22 0.38 1.23 22.4 91 7 301 132 S3 l 13.3 3.28 615.6 isse 144 a 7B 0 52 QI 1 24 32 4 948 246 2OS 102 17 3 l 3’ 703.4 1989 2 36 a 63 G4B 1,08 0 76 8.4 30 4 80.1 28* 'D2 696 8.52 US.4 1990 Z24 095 1 36 2 82 1 53 12 9 44 246 205 102 15 5 5 24 619 8 *962 &S4 062 026 0.5 2.48 133 49 1 i?9 M 4 172 13.0 3 72 534 7 1993■ 1 56 OB* 084 2 37 6 63 36 5 107 308 119 57 ? 155 2 94 66D.6 199* 1 34 0 48 031 0 32 268 22 89 2 335 194 12 5 337 1.24 562.4 19M 046 0 23 029 045 i 31 4.63 22 4 98 7 78 2 12 5 275 5.24 227 1996 1 70 0 6? 0 71 0 93 10 7 51 2 MS 189 109 102 155 49 631 5 200- 4 72 2 83 3 15 2 55 9i 57 5 ISO 26’ 250 129 21 1 7 29 899 3 2002 6 01 2.56 2 37 301 i 78 152 105 103 20 1 7 62 4 61 3*1 1 2003 2 44 1 26 2 43 3 88 1 69 8 37 123 123 205 102 15 5 5 24 594.5 2 IB 1 43 09 084 3 08 19.2 87 1 119 122 90 2 10 7 5 24 461 9 tic Water Works Design & Supervision Enterprise in AsiDtlinoa with UtertcmUannLU coBBultnnu lad TecJmacrets Pvt LidirjyfkdtMi Irrigation Project MEieorologtcal and ihdrological Aspects 2007 . Bfr Situation■ AreaOpatrt). Pelatlonships E.'eirefjon Area Volurrw g/evetton (mwfl (km*) (Mm*) _ 132C 0 54 0 0 1356 1321 09? 1322 2 39 1323 3 73 1324 5.11 1325 6 64 1326 8 03 1327 9 46 "328 10 87 1329 12 6? 1330 14 40 1331 15 89 1332 17 74 1333 19 46 1334 23 59 1335 26 66 1336 29 05 1337 31 73 1336 34.24 1339 36.62 08 1357 25 1358 5 5 1359 10 0 1360 159 1361 23 2 1362 31 9 1363 42 1 1364 53.9 1365 67 4 1366 82.5 1367 99 4 1366 1180 1369 139 5 1370 164 6 1371 192.5 1372 222? 1375 255 0 1374 291 3 1375 134C 39 45 329 3 1376 ,_ ■---------- —' of Afjo Dfrdetaa Resurvoir Area Voium* B? 05 1^41 2 90.75 1430 5 94 18 1522 9 97 23 1618 6 100 54 1717.5 103 64 1019 6 106 39 1924 6 109 00 2032 3 111 91 2142.B 11505 2256 3 117 58 2372.6 120.20 2491 6 122 76 2613 0 125 28 2737 1 127 69 2063 5 130 25 2992 5 133 03 3124 2 135 45 3250 4 138 oe 3395 2 142 36 3535 4 145 27 36792 1341 41.97 370 0 1377 148 00 3825 8 1342 44 25 4131 137B 150 75 3975 2 1343 47.05 458.8 1379 153 73 4127 5 1344 49.96 507 3 1300 156 02 4282 3 1345 53 11 558.8 1381 159.05 4439.9 1345 56 31 613.5 1382 162 13 4600.5 1347 59 15 671 2 1383 166 96 4765 0 i34S 51 56 738 8 1384 173 01 4935 D 1349 63 97 800.7 1385 178 5S 5110 8 1350 6? «8 874 7 1386 183 38 5291 B 1351 70.62 943.9 1387 188 10 5477 5 1352 74 35 10164 1388 193 28 5668.2 1353 77 68 1092.5 1389 197 36 5863 6 1354 81 28 1172.1 1390 201 95 6063 2 1355 84 51 1255 0 I Water Warks Design & Supervision Enterprise la lUncUdm *1u [mereontmimj CcbsuIUdu ud Tect>nacr»tj Pn. |.cd------ uh h ift JI LUJCrVli. Meteorological and Hydrological Aspects Hiy 2007 Sample Simulation Result? of Arjo (Jeder.sa Reservoli Y»ftr 1 Monlli 2 Inflow a DF (mJ.'sJ 4 £o Rf {mm) 5 IWD (Mm3J 6 <Eo Rib < Mnr 2) 1 5L rMnpjj a rwR I Mm J) » OS (MmJ? 10 SfyMge (Mmjj fT 92 Levo/ fm 13 Spin iMmJj 14 S7RQ 1r*5 r SpWl JMmJJ 16 404 Sep 377 4 00 0 00 00 10 00 676 4 1906 3 74 1 ' 1351 9 576 4 4U4 Oct 333 3 oo 1 ti 00 S2 10 00 3?4 I 1006 3 74 1 1351 9 124 1 404 Nov 102 7 00 143 46 2 10 6 10 46 2 44 9 11106 3 74 1 1351 9 44 9 404 Dec 47 7 DO 135 60 0 100 10 600 23 4 982 9 73 1 1351 5 DO 404 Jan J? 5 00 146 74 0 10 7 10 /4 0 63 7 919 7 70 4 1350 7 00 404 i eb 72 J 00 147 85 0 104 09 85 0 ■84 0 035 8 66 7 134CJ 4 no 404 Mar 16 J 00 164 50 4 109 □A 50 4 459 789 9 64 6 1340 7 00 404 Apr is a 0.0 146 74 94 oa 74 09 789 0 to h 1348 7 no 404 May 40 1 00 so oo 51 08 00 34 1 823 1 66 1 13492 on 4G4 Jurt 7« 9 00 0 00 00 08 00 160 1 963 2 73 1 1351 6 00 404 Jul 4CW 3 00 0 00 00 10 00 399 3 1006 3 74 1 13519 376 3 404 Aug 647 4 00 0 00 00 1 0 00 6464 1006 3 74 1 11351 9 646 4 189 405 Sep 717 9 00 0 00 00 10 00 7W9 1U06 3 74 1 H3519 716 9 405 Ocl 777.8 00 111 00 62 10 00 768 6 1006 5 74 1 15519 ?63 6 its Waler Works Design & Supervision Enterprise Ln Association with IntercoalJoenUil Consultants and Technocrats Pvt LidAj]v Oedessi LnioUoa Project Meteorological and Hydrological Aspects Mar zw? 1 1 3 4 FH ".I 7 a a 10 11 i_« I “ ----------- — ■ 1 T3 « rs I» 405 405 T OO 143 462 106 1 0 46? 347 3 10063 74 1 1.351 9 34? 3 4L15 Dec 00 135 60 0 100 1 0 600 122 fl 1006 3 74 1 1351 9 122 fl 4Q5 Jan 40i ■ eb 4Q5 Ma> 405 Apt 405 May 70 3 □ 0 146 74 0 109 1 0 74 0 rlSS 990 9 73.5 1351 7 on 49 7 □ 0 147 65 0 10.0 1 0 49 9 □ 0 164 504 11 7 09 313 □ Q 146 74 10 3 03 435 0 o 00 00 5 7 09 85 6 -46 1 942fl 71 4 504 16 2 926 6 70 7 7 4 126 939? 71 3 1351 0 00 1350 a 00 1350 9 00 405 Jun T49.4 00 0 00 00 1 0 405 Jul 459 4 00 0 00 0.0 1 0 00 0 00 00 1 0 OO 00 00 36 9 976 1 72 0 1351 4 00 145 4 1006 3 74 1 1351 0 116 3 455 B 1006 3 74 1 1351 9 465 0 639 7 IQOF, 3 74 1 1351 9 G39 7 SM G I 405 Aug 640.7 00 406 Seo SlflS 00 0 OO 00 10 00 5156 1W63 74 1 1351 9 5158 406 Od 402 9 OO 111 00 62 10 00 303 3 1006 3 74 1 1351 9 393 3 406 Nov 1662 00 143 46 2 106 10 46 2 ma 4 10063 74 1 1351 9 100 4 406 Dec 71.S oo 135 600 10 0 10 600 05 1006 3 74 1 1351 9 05 406 Jan 31-7 00 146 74 0 10 0 10 74 0 54 1 952 l 71 6 1151 1 00 406 Fob 24 & 00 147 *5 0 10 5 10 85 0 • 71 7 080 5 6fi 7 1350 l CO 406 Mar 1T0 00 164 504 113 09 504 ■456 KM 9 667 1349 4 oo 106 Api 13 5 00 146 74 9? OH 74 45 4430 4 605 1 349 4 00 i bi Waterworks Design & Supervision Enterprise [n Association with InterccinLintnul ConsultariU and Tschnomts JM Ltd«■ £1 g ■IZDs I“1 M F3 n 8 <P ID ao S£l O ta 1% eft lU f’*! iT It- ©n => T 0 n> £2 oa »* r* Ci at OJ au tS Tr »T up C. S’! rn.. Cl Cm n c o 3 ■— OD s fc T =D -n ID <i 5 “J ■* n ■ul O ■JI r-} !■- <S n o FM T” r> IO S3 oo O O a Cm Oq ■c Q d e Q Qj Tf g O o ±> o - *n O c? & a o Q o o o e 5 o o ta m s s X ►« ISi *n □□ V ■--■*d =*> V- O u *■ E £ 5 8 8 "7 T ™fc 5 d O 5 U1 n tR_ > ■5 rr s r«- 3 t*-. ■Q ■T o Z fM c- TArjfl Cedessa Irrl^adflu Project Meteorological and Hydrelugical Aspects __ k*}' 2007 ' Annex C: Standards Cl. Commonly used values of runoff coefficisn Class Description of catchment A Fiat, cultiyaieo and Dick cotton soils B Flat, partly cullivawd stiff sails C Average catchment D Hills and plains witn little cuHivabon E ve1. hilly and steep with little q* no cultivation. Runoff percentage 10 15 20 35 45 C2: Runoff Coefficient for pervious surfaces by selected hydrologic sori grouprngs aria Terrain Type / i slope ranges Soil Type __________________ B c D Flat <2% 0.04 - 0 09 0 07 0 12 0.11 - 0 16 015 - 0.20 Rolling, 2 ■ 6% G 09 - 0 14 012 - 017 0 16-0 21 0.20 - 0.25 Mountain. fr-15% 013-0.1A 0 10 - 0.24 0 23 - 0 31 0 29 - 0.30 Escarpment >15% 0 IB -0 22 0.24 - 030 0 30 - 0 40 0.38 - 0 4B NrjLt Whm A. B C and D are defined as shown in C3 121 Water Works Design & Supervision Enterprise Id Assrjtlainni with IntercontlntDiak Consuldnts and Technocrats Pvt. Ltd4rjo DetfEssi imgauM Project Meteorological and Hydrological Aspects ■far 2007 Cl: SCS Curve Numbers for Various Conditions Cover Descr/pf/on J Cover type Hydrologr c condition A Curve numbers for hvdrolooic soil qroup 8CD I Fallow flare soil 77 86 91 -----XT.- 1 94 Crop residue cover ,CR) Pasture grassrand. ex range- conlmuDus forage for grazing' Meaoow-conlinuous grass. 35 59 72 79 protCCled from grazing Brush-weed-grass mixture with Poor 48 67 77 83 Poor 75 65 90 93 Good 74 83 88 90 1 Poor 68 79 86 89 Fair 49 69 79 Ba Good 39 61 74 8u brush me major element3 Woons-grass combination’ Woods* Fair Good Poor 35 56 70 77 30* 48 65 73 57 73 82 86 Fair 43 65 76 82 Good Poor Fair Good 32 58 72 79 45 66 77 83 36 60 73 79 30* 55 70 77 Farms—CuiWings ranes driveways. - 59 74 82 86 and surroundme 101$ >Vrd and semr-awo1 range/antfse Hyd cond' 48C Mixture of grass, vreeos. and iow- Poor — 80 87 93 growing brusn, with crush the minor Fair — 71 01 89 etemsni Mountain orusn mixture of small trees ano orusn Small frees with grass unoerslory Poor — 75 65 89 Fair — 58 73 80 Good —r 63 74 85 Poor 66 74 79 Fair 48 57 63 Good — 30 41 46 Good Brusn witn grass jndersiory Desert snrub Drusn — - 41 61 71 Poor — 67 60 65 Fair Good — 35 47 55 Poor 63 77 05 86 -- - 51 63 70 Fair 55 72 Good 81 49 86 68 79 84 Water Works Design Supervision Enterprise tn Association with Intercontinental ConsuliMts Technocrats Pvt LtdArjo Dedtssa Innfatrun Project Meteorological and Hydrological Aspects C3; (... confrnueW Average runoff condtfion. and I. ■ 0.2'S " °0€i * 5u% ground cover or heavily grazes wim no muren Fan 50 io 5% ground cover ana nut heavily grazed- Good ' "5% ground cover anc iigmiiy or only occasionally gr<uec 3 Poor < 50% ground cover Far SC io 75% ground cover Sdod * 75% ground covet May 2007 7 . ‘ Aciuai curve nufnoer is less than 3d use GN = 30 tex runoff compuia ors r-^miwkalion* of : CHs M»wn rt<e cwipulod For areas 50% (pa*Jure> cover . e conSfliDris ma >■ oe KKnpuled Troffi CN s ror *ooJS and pa s iui e ’ P«r Fiwrt MW smal wrts, and are a«uoy«J &y heavy graz.rtg or regular nr r»muiar . Far Gd<k ________ ________ Outniftg Woods grazed Oui riert burned, and some forcs-i litter covers c e 501 Woods protected from grazing, litter ano bruin adequately cove* sc p-:xx < M % grcHMMJ cover filter grass and crush overstory ■■ Fa>r 30 la 70 % ground covet Goaa * 70 % ground cover Sort Groups grpup jCi Sana , loamy sa-no or sanoy ioam Soils having a low runoff potential due to high mhltraiion rales These sorts primarily consrst of deep well-d rained sancis and1 graven Group fi Silt oam or 10am Sorts having a mooerateiy low runoff potential due to moderate infiltration rates These sorts primarily consist of moderately oeep to deep, moderate^ well co well drained sails with moderately fine to moderately coarse textures Group C Sanoy ciay loam Soils having a moderately high runoff potential due to slow iiMiHralion rates Tne&e sods primarily consist of soils in which a layer exists near the surface Inal impedes the downward movement 04 water or soils with moderately fine [0 fine texture Group 0 Clay loarr, salty clay loam, sandy day, silly clay or oay Sorts having a ntgh runoff potfrniiac due to very slow infiltration rates These soils pnmarily consist of ciays wtr n»gn swelling potential, soils with perman-en!ly-ri»gr water Cables soils with a day pan or ciay layer ai or near the surface, and shallow sorts over nearly impervious parent material r 123 Water Works Design & Supervision Enterprise In Association with hinrwntlnonul ttnsultanu and Ttchnocrais Pn LtdAr jo Utdessn Irrigation Project Meteorological and Hydrological Aspects Mi) C4: Reservoir FIftfld Stand ards Dam design flood (inflow Min Standard, Category 0/reservoir Initial Gerrera/ condition Spilling long term av A Breach endangers in Daily lives m commentary inflow S Breacn may endanger li^es nd in PMF Larner ol 0 5 PMF ar Rare overtopping Largtf of 0.5 PMF or '0.000 yea' flood Larger of 0 3 a community 10 000 year PMF Of 1,000 extensive drainage Full C Breach win negligible risk iq hie and causing limited aamage Full flood Larger of 0 3 PMF or 1.000 year flood year flood Larger ql D 2 PMF or 150 year I loot? A(ofe Pcx r/v purpose of PMF tne (riintfti uf ffre jompufpd are Dy fhe proportion indicated bV/nd speed, M/rt wave surcharge Average annual max Hourly wind Wave surcharge allowance >06 m Av Annua* max houhy wind Wave surcharge allowance >04 m KF nytJrcgratfh Water Works Design & Supervision Enterprise In Association with IntereontlnuiuL Consultants and Technocrats Pvt Ltd-Arjo Dedessa Imjatlcm Project Meteorological and Hydrological Aspects CS; Ratios of the basic dimensionless hydrograph of the SCS TJTp Cii.'Qp TiTTp QnQp Ti/Tp QuQp 6 0 1.05 0 99 26 0 13 0 05 0008 1 1 0 98 27 0.11 0 1 0015 1 15 0 95 2 6 0.098 0 15 0 043 1.2 0 92 29 0 088 0? 0 075 1.25 0 68 3 0 075 □ 25 o.n 1 3 G S4 3 2 0 056 0,3 0 16 1 35 0 60 35 0.036 0 35 0.22 1 4 0 75 37 0 027 0.4 0 28 1 45 0 71 4 0.018 0 45 0 36 1,50 066 4 2 0 014 OS 0 43 1 55 061 4 5 0.009 0.55 0 52 1 6 0 56 4.7 0 007 0 6 06 1 7 0 49 5 0 004 m*j ajc? 0 65 0 69 ia 0 42 07 0-77 19 0 37 0 75 0 83 2.0 0 32 0.8 0 89 21 0 25 0 85 0.93 2.2 0.24 0.9 0.97 2.3 0.21 095 0 99 24 0 10 1 1 25 0 16 B I Water Works Design & Supervision Enterprise In Association with Intercontinental Consultants and Technocrats Pvt Ltd.ArJti BcdEssa rirlfitJM Frojcd Meteorological and Hydrologica l Aspects _________ ____ C6: CuIMl™, tor .rue,prelates of Water Ooality for irrjga|ion Waler parameter Symbol U SALINITY Sall Contani __ — Eieciricai Conouctfrly ECw dS;rr. 0-3 dS/m (Of) Teiai Diswi^ea Solids 70S mgl 0 - 2000 mgi'l Gallons and Anions Calcium CaT me/i 0-20 me/l Magnesium Mg" me/l 0-5 me'l Sodium Na" me/l 0-40 me.'l Chioripe Cl mefl 0-30 mert NUTRIENTS" Potassium mg;E 0-2 mgfl MISCELLANEOUS Aci<j;Bs&icJly pH 1-14 6.0-8 5 Sodium AdMMplipn rtatio3 SAR (me/l)1 2 0-15 Source fACt ’99* Urjjarr Quaftfy for/ipnGurfunj. and Drainirge Paper Na Hiir 1 RttmnieU. ’99* 126 Water Works Design & Supervision Enterprise In Association with Inierconuutoial Unsuli>nts and Technocrats Pin. Lid.Arjo Deaessa Imgaunn Project Meteorological and Elydrolcglcai Aspects Ann ex D; M eteo rologic a I Da ra Pl: Dtiails of Meteorological □bserwalJon Slatians Miy 2DO7 Station Name S.No. 1 Agaro 2 Arjt Latitude North Longitude East Altitude 1 crass D(*g. Mtn. Deg Min -• (mj Period OB 45 30 30 2565 1972-2004 3 or Si 36 36 2030 198U-20O4 1 3 Bedehe 08 27 36 20 203D 1967-2004 1 4 Deaessa 59 23 36 06 1200 1971-2004 1 5 □emtx 08 04 36 27 1950 1954-2004 3 6 GimD« 09 10 35 47 1970 1978-2004 1 7 Jimma 07 40 36 50 1726 1952-2004 a KOfte 9 Meno oe 41 36 oe 2000 1980-1989 4 10 Ne*emie 09 05 36 28 2080 1971-2004 1 08 41 36 47 2U0O 1979-2004 4 11 w_-___ - Wama 0B 59 36 40 1450 1980-1987 3 D2: Types of Climatic Data available at the various Meteorological S.Na Station Name W ’Yrs RF TM RH ws SD 1 AgSrO 2030 25 X X X X X 2 Ai>j 2565 33 X X 3 Beoelle 2030 38 X X X X 4 □eoessa 1200 34 X X X X Altitude EP 5 Demoi i960 51 X X 6 GimDf 1970 27 X X X X X 7 Jimma 1725 53 X X X X X a Kone 2DDD 26 X X X X X 9 Meko 2000 10 X 10 Nexemte 2080 34 X X X X X Wama >450 3 X X RF monthly rainfall SD sunshine duration Tm average lemperature reler co rainfall series relative tiumtdity wind speed 1 nr maximum 1-n.our rainfall RH WS 1 day maximum 1-day rainfall Rday number or rain days_____ " Dara itfrXNfi /efers re ftarfifarr and rcrapBratare owe 127 Waret Works Design & Supervision Enterprise [n Assucjitlun wltt iDt'reomineniai CmbuMwuk utfTecbiutTitsPviLtLArjo MtSsa IrnfaLlcn Prn-jEcl MjieoroId^JcaI and Hydrological Aspects 03: Mean Monthly Ramfafl al Settle Station M»J EOC7_ Jan Feb March April Miy June July Aug Sept 'Ocl 1967 IMS 1969 1970 Wi 1972 1973 1974 1975 1976 1978 1979 1950 1983 1984 1994 1995 1996 1997 1998 1999 2000 200'. 2002 2003 2004 0 0 152 33 1B1 ?Sl 212 J$1 360 167 0 iW i 55 163 0 323 380 324 137 67 59 Bl i90 710 250 275 36$ ies 9B 54 50 69 258 258 266 432 200 444 186 253 0 null 1980 35 22 1539 7 0 1897 20 1 41 53 246 334 311 234 455 326 0 20 42 178 TIB 263 337 267 207 0 19 10 51 337 zee 322 403 248 110 102 66 13 55 9 497 355 351 292 368 126 44 :0l 37 105 202 JIS 337 276 245 22B 41 29 15$ 97 0 267 333 373 472 154 5 7 I’S 179 204 J67 J3t> 303 201 ZtM 0 0 W 44 169 350 4M 276 267 113 0 0 0 20$ 285 174 236 304 363 SB Q B 48 62 237 369 4^ 466 306 197 0 0 45 66 291 275 46$ 2H 242 9 2 34 80 141 243 222 218 357 200 103 1? 2 33 100 225 2B1 250 25B 276 21 0 17 102 130 257 292 257 310 353 77 4B 34 208 83 317 232 290 203 120 70 53 2 50 142 340 307 221 304 232 309 13 15 07 57 203 332 314 327 291 245 20 3 13 147 431 441 319 242 324 329 0 0 4 133 256 420 ’86 273 286 242 0 33 07 72 322 390 297 329 370 211 16 4 03 30 1B9 29B 290 202 253 S3 7 66 B4 131 37 320 270 256 197 52 6 3 46 01 343 447 299 268 273 160 07 56 25 i22 26 21 iQ 0 29 20 0 62 9 4T T2 00 50 0 2322 2101 1788 1790 2171 1796 1993 1926 1655 1706 99 0 2293 26 5 1637 i0 17 0 ID 24 1580 1484 1837 45 13 1670 aa 4 59 1 2001 1942 8 39 2321 29 B 29 14 3 46 13 3 1827 2155 1450 1446 62 15 1917 23 65 Jt35 239 291 310 303 302 IJnB *1 12 ’ 25 * 28 3 J5 1 8 0.77 F u9 0 58 0 454 0 312 0 2<2 02? 0266 0.563 1236 1 114 0.68 0 090 ■0.91 0 837 0 56 0 345 0-375 2 913 i 172 W 101 20B 255 497 447 499 468 472 32B 253 46 0Q090 0 ?86 202 T29 9 0 0 1864 0 14 0 18 2322 144$ J Water Works Design & Supervision Enterprise In ASHKtidM With Inurconunental OnnttUHi and Technocrats Pn LidAt]q Deiesii ImgauoD Project Meteorological and Hydrological Aspects 04: Mean Monthly Rainfall at Jimma Station ___ (inmmi_________________ _____ ______ - T«r Jin Feb March April Ma)' ZOO" Aw Sept Oct 1953 1954 1955 1956 19S7 1958 1959 1980 1961 1963 1564 1955 I960 1967 1966 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 i960 1951 1942 1963 33 49 88 T33 283 399 211 255 116 0 49 00 T33 210 214 152 27 33 49 85 135 91 25 100 109 29 4 83 250 0 52 117 215 43 06 53 13& Bi 140 06 138 11 3<* 104 i<5 0 86 98 225 40 57 131 110 43 4 39 203 21 73 100 153 79fi 194 235 244 169 183 288 254 215 226 169 195 270 292 170 2T9 237 185 203 272 135 iB9 215 ’30 249 S2 285 151 210 212 272 262 243 206 221 206 225 249 205 191 58 161 307 172 139 4 15 19B 02 273 207 233 250 3 74 63 105 55 81 199 91 78 135 91 100 18 3 50 81 12 74 127 115 20 11 7 149 5 56 TO ’03 4 65 100 ’71 36 65 107 112 n 56 54 10 5 71 42 130 32 110 111 23 233 173 240 210 165 189 105 104 288 197 263 148 153 205 204 20' 161 159 193 167 150 297 160 101 165 221 265 240 198 252 194 151 124 211 233 190 TO3 50 110 80 57 130 35 97 154 107 55 132 31 S5 149 55 57 25 95 93 197 203 265 191 229 1 88 36 16 3 25 15 68 68 22* 24 ng 215 59 35 68 107 103 10 1 7 110 61 222 104 215 203 232 153 164 115 134 57 23 42 100 30i 189 1 7 130 62 105 43 61 136 20 40 97 161 114 193 '64 250 141 154 223 141 192 157 70 109 31 94 9 27 127 212 3 36 23 96 3 11 42 3? 28 73 109 25 13 2 $5 5 36 44 0 10 1 55 25 15 35 22 2ft 1 37 Annual 1743 1270 1507 1523 150B 1446 1604 1509 1494 2012 1606 1341 1333 1819 1400 1253 1743 1465 1350 1237 1479 1414 1723 1491 1442 1169 1326 1337 1611 19B4 24 11 32 83 1985 1966 1987 1938 19B9 1990 199’ 1J3Z 168 183 136 256 204 174 229 299 141 S4 7 1614 25 20 77 14J 0 48 02 H5 26 89 :5B 60 01 59 31 67 28 47 138 179 25 40 133 56 79 81 62 169 28 58 56 162 211 166 187 260 160 120 233 134 163 12 63 09 188 100 136 116 165 185 294 220 179 232 213 204 320 280 280 245 *7? 107 23 138 50 14 46 2 28 93 S 70 50 12 47 52 0 1208 1297 1331 1440 1477 170 1627 223 2B7 200 246 140 51 212 344 175 150 19 76 36 1712 1445 1749 129 Water Works Design & Supervision Enterprise In AssMiBtien witu ImerwotinentaL CcnsuBuoLs and Technocrats Pvt ltd.Ajjq tJrdtiM Irrigation Project Meteorological and Hydrological Aspects Q4; continued^ ^ar Jan Fro March April May June July Aug Sept Oct Dec Annual 1993 1994 1995 1996 1997 1994 1999 2000 2001 200? 2003 2M4 I— 9 01 110 237 237 225 1tt?t 263 164 17 3 0 ?3 20 07 153 213- 274 255 155 177 11 16 11 a 2? 74 193 H5 -63 101 216 I4t 54 30 95 35 22 135 203 175 183 231 91 245 24 93 40 65 49 69 170 274 237 122 276 140 31? 24 3 36 103 22 97 93 174 223 243 307 200 201 47 1 30 1 64 72 214 575 136 102 131 196 1 2 0 1 39 194 210 ’54 266 ise 255 244 47 25 16 13 06 117 341 299 312 161 183 ">63 76 4 69 5 11 90 137 242 150 235 165 00 a 110 29 61 87 HI 12 272 187 151 239 92 30 15 51 24 46 131 162 126 216 219 210 133 67 89 1534 1415 1298 1476 203* 1713 1540 1622 1772 1330 12B6 1402 CV 5*flw Max JWji*i 33 49 W JJ3 172 219 2tW 2T0 702 103 60 36 O.fffi 0 7j 0 4t 0 43 039 034 0 24 0 26 0 26 0 67 0 96 T.05 0 95 9 60 0 55 0.41 041 2 53 0 3 r 0 f2 0 04 1 TO T 32 T 74 ;os r4C ?99 30? 34T 575 312 344 299 337 243 170 0 t 7 16 12 114 9F 9f 50 TT 1 0 15C2 0 13 0 0J 2034 T769 130 Water Works Design & Supervision Enterprise In Association with InttKontlneiittLl Consultants and T&cliiHMniis Pn. ltd4rjo Maia ImgaOnn Project Wteoro logical and Hydrological Aspects OS- Mean Monthly Rainfall at Dedessa Station V«r Jan F»U Warth April May June July Aug Sgpl O c< mqV d«c_ — 1971 1972 1973 1976 1977 197A 1979 19B0 19B1. 1M3 ifta. 1985 :«g 1987 1M8 1989 ^990 1M1 1992 1993 "Km 1995 -986 1W7 1998 1999 2WJ 2«H 2042 2<W3 ZC-IM 40 11 6 5 90 1&7 2B3 497 21 (i 0 0 3 41 266 273 203 289 iSI 146 152 123 0 B5 14 1579 1222 00 217 196 0 0 □ S3 80 0 0 0 0 0 191 245 197 0 0 2 13 228 285 272 240 104 121 49 289 193 139 0 48 39 88 i&0 0 0 35 11 244 207 205 96 39 00 334 625 401 196 107 5 0 3 4 0 0 7M 1128 1278 1695 0 0 9 20 221 306 25? 309 1 0 47 89 219 318 373 295 0 5 12 73 50 184 339 259 4 3 25 29 141 399 425 296 1 5 32 8 275 341 370 442 0 0 :60 38 24 3 269 337 289 4 10 39 2 11 250 402 245 7 J7 33 74 101 215 355 104 4 0 0 0 84 197 153 207 0 6 26 95 14T 224 307 264 0 0 1 79 0 0 34 19 Bl 112 285 241 21 4 71 60 239 311 3B0 380 13 0 13 154 184 203 277 24? 0 0 13 14 251 395 196 371 IB 0 0 47 178 306 iSi 274 0 0 a -.54 241 448 136 347 0 11 27 3i 143 214 196 224 6 IS 30 3i 77 203 252 126 0 35 50 0 73 366 417 302 0 5 6 35 105 252 427 310 123 158 221 215 □ 140 94 97 1306 1695 1284 380 241 305 120 152 53 1691 2101 1880 1216 132 5 171 163 170 132 17? 370 147 254 351 89 0 0 191 141 300 192 254 128 60 20 14 7 68 32 8 27 5 54 3 22 19 1 55 15 10 12 6D 29 17 22 40 0 38 36 ■■1 23 1 1 □ 76 0 10 6 0 1251 1069 1382 CV Shew Ma. Wtan 3 6 26 49 156 274 312 277 1. 91 T 87 1 28 oea 0.5T 0 29 0 37 0 25 2 IB 2?8 2 75 0.94 ’0 25 0 25 0 54 0 36 21 48 160 154 275 44B 625 442 0 0 0 0 0 112 138 126 102 193 140 299 0.3& 0 87 3S0 102 17 67 147 1LM 0 64 -0 04 241 0 5 Q 0 0 11 0 29 6 6 0 8 2 D5 3 66 76 0 1032 1856 1299 1717 1494 1842 1296 065 1544 1470 1426 0.23 005 2101 764 Water Works Deslpi & Supervision Enterprise in tottditiu with Imerconunentu Consultants ar d Ttchnacrais hm Ltd. HIArjo Dedessa Irrigation Pnojtst Meteorological and Hydrological Aspects 06; Mean Temperature at Bedele Station (moC> May 2007 —— jin Feb Mar Apr May Jun jul_ 1971 17 9 19 S 2i 2 2G 8 2i 3 20.4 132 167 i® 6 15 5 154 17 2 1972 T9 5 209 10 4 17 9 19.6 18 3 1973 179 7 21 5 21 5 19 4 179 14 3 1974 17 7 19 8 T9 3 20 2 ie 7 18 2 ’6 9 1975 17.3 19 3 19 7 i9fl 19 4 17 7 1® 7 1976 17 9 1® 1 “9 i 18 8 17 8 1 7 6 1977 1B2 19.0 1976 173 193 18 9 186 17 5 ’979 ’98C ji 0 20 5 19 7 19.5 79 166 19 2 19 t 17 5 17 2 1901 171 17 5 17 1 17 0 21 J 2i 2 22 0 19 7 100 169 ms 20.5 205 21 4 5 18® 180 17.2 1986 19 9 20 6 20® 20.9 21 4 10 1 17 4 IM 7 194 20 8 204 1988 19? 203 2O.B 21 5 19.6 10 1 17 0 19W 178 IB 7 19 i 19 3 190 17 0 150 iSrSO 18 1 1®7 19 5 20 2 193 18 5 174 1991 193 20® 20 7 21 0 204 18 3 1992 19 i 20 1 21 3 20 6 207 19 5 184 1982 1W3 7 5 19 1 20 1 17® 174 17® 1B 3 18 7 i90 19 4 20 0 Aug Sep Oct Nov Pec 158 159 1&4 180 17 3 17 4 24 9 15.7 17.2 17 1 17 9 17 9 16.2 17? 18 1 17 2 17 2 17 1 177 17 1® 7 168 160 16 1 :9 ? *60 18 5 1? 3 17 3 17 5 16 9 17 4 17 0 176 17 4 T® 9 19 6 1 17 7.31 11 77 43 177 18 8 189 17 6 17 7 ia 2 18 7 184 IS 1 1B2 18 3 190 17 3 1? 5 18 3 182 17 9 1 1 7 743 117787 1178.25 1100.09 1197 B1 17 4 18.2 1B4 18 7 20 0 IB 0 19® 19 1 IBB 20.8 1993 1994 209 20 9 22 D 21 3 19 5 17 8 17 7 182 19 £■ 198 19® 1995 20 5 20 0 2i 3 21 4 tSJB 19 4 17 6 18 1 18 5 18 8 189 19.5 1996 19 2 21 0 ?□ & 20 7 19 1 IB 4 17 8 18(1 18 3 18 3 IBS 18 7 1997 192 15 9 21 5 155 19 3 18® 17,® ISO i® 8 1998 139 21 2 21 2 232 21 0 19.3 18 1 1® 3 IB 9 1&2 186 192 17 7 16 6 17 9 184 19 2 17.9 16 5 169 18 ® 109 209 21 T 20 7 21 6 21 2 21 6 19 9 100 21 2 18 5 175 18 3 177 17.5 10.6 18 1 19 4 18 1 18 7 192 18 6 189 21 5 2i o 21 1 22 i 21 2 21 5 21 5 10 7 208 18 3 1999 196 21 7 21 7 21 & 19 1 18 7 17 3 2W0 17 7 2001 19 1 2002 19 2 2003 20 0 2MM 20 & ?8 7 1?& 17.8 1® 1 18 1 106 186 19 0 18 7 19 ® 19.® 19 1 19.6 T9 7 206 20 8 T9.6 ISO 17 3 174 T79 18.0 ?8.3 T8 9 CV i? M 0.13 0 05 005 0® 0 12 0 05 0 [)4 0(J5 0 05 0 06 0 09 Sxe* -T 21 -3 96 -T IS -0.08 3.00 ^.24 -2 06 -0 86 -0 58 -42.54 -1 35 T 44 Jtfin T3 9 75 17 1 18.4 17® 79 ?4.3 15 7 160 15.5 15.4 15 9 JO.P 2? 7 2? 1 23 2 21 9 20 4 18.4 IS. 3 T9.® 1.9 4 F& 7 20 Water Works Besign 4 Supenrisltm Enterprise In tssociauirn nitb IntertontlneniaJ CctisultMta aod Technntnts Pm. Ltd.ArjolieDtisalnitratHH] Project Meteorological and Jlvdrctugica I Aspects D7 R eutivo Humidity at B g go le St at fo" ■,r % 1 •it Jtn FsC Mtr Apr .Way -Ju" jLfl _ _ _ _ _ . ___ 9007 ■ ■- 198? 19BB 80 56 52 70 75 60 84 83 76 63 SO 1990 59 62 56 BO 70 rd- 82 60 80 70 60 60 i9aa 51 S3 67 &2 M Hi' Sop Pel ■ No¥ -D** 00 ■HO 60 50 63 8$ H4 72 64 75 1991 55 « 55 67 76 BC 62 04 77 71 65 65 199? •58 65 50 62 SS 75 1993 1994 53 4 5 46 57 76 Bl 1995 46 M 51 59 72 ?□ 85 63 70 69 6A 67 7? 61 74 72 69 « 65 72 81 61 66 61 1996 59 M 63 62 75 82 1997 55 L99S 55 55 64 1S» 59 50 49 55 76 7b 2000 58 S3 04 6b 72 68 w 64 aa 80 76 64 63 82 84 82 60 74 70 2W1 62 62 65 65 73 Bj 84 84 83 00 74 87 KW 62 55 63 60 57 61 86 06 94 73 69 61 20W 61 54 56 62 66 fill 85 84 82 7.1 70 69 Arfr..^ 60 57 58 70 78 84 83 87 89 63 — 59 60 66 65 67 61 65 86 83 135 Water Works Design & Supervision Enterprise In touctoion wUi lnttrconHnsntai Gansultanu aad Tfchnoenis p Ltd. nDtfessa Irrigation Project w MeteoroloRical - - - - - - - - - - - - - ii i ■ and Hydrological Aspects D8: Wind Speed at Jimrna Station pn m/sj freer .an Feb March April May Jwrw July Oct 1973 1974 09 1975 09 1976 oa 1977 □ ? 11 12 09 1 2 00 1 3 07 1 0 1 0 08 09 09 1 1 09 14 3* C9 09 10 09 Wfl 07 08 1 2 i 1 09 09 08 09 □a 08 08 07 □8 08 03 J 9 09 00 09 09 09 09 09 08 1979 C 9 0 8 OS 09 06 0 9 67 00 08 1980 07 1961 07 06 0.9 0.9 0 0 0 7 0 7 07 0 7 00 09 07 a a □ y 3 6 0 7 1902 0 7 OH 06 08 o h 07 06 06 06 07 03 11 OB 09 aa oa o7 o& 06 06 0B 09 00 08 07 10 0& oe o5 05 09 09 06 07 oe 07 07 0.6 06 05 1963 0.6 1964 06 0 0 0 7 o 7 0 ? 0 6 0 6 06 06 0 6 0 6 1985 06 □ 6 06 05 06 Ob 0& 05 06 1900 1907 198B I 1989 1 1990 1991 1992 1993 1994 1995 fc996 1997 1998 1999 20OC 2001 2002 2001 2004 OS 0 8 07 0 6 06 0.5 0.5 0 6 05 04 0.3 0 3 05 05 06 0.6 0 5 05 05 04 04 0 3 02 0 3 0 1 0 i 0? 0.2 02 0 1 0 1 0 i 0 1 0 1 0 1 U 1 01 01 ai 01 0i 01 01 o1 01 □ 1 01 01 05 06 0 6 06 □ 6 05 06 06 0 6 06 0 6 05 0 i 0 1 0 1 0 * 0 1 0.2 0 1 0 1 j i 0 1 0 1 0 i 06 06 07 0 7 07 06 05 0 5 fl 6 0 5 0 5 05 05 0 5 0.6 06 0.5 0 5 05 0.5 0 5 0 5 0.6 05 0 1 01 04 02 03 0 l 0 1 0 1 0 2 0 1 C t 0 1 04 06 0 6 0 5 0 5 04 04 0 4 04 04 0 4 05 04 D 5 0 6 05 04 0 4 04 0 4 04 04 04 04 04 0 5 □ 6 0 5 05 0 4 0 4 04 □ 4 0 4 0 3 04 04 04 05 0 5 04 0 5 03 0 3 04 0 4 0 3 03 03 0 3 03 03 0.3 03 0 2 0.2 02 0.2 02 02 0 3 03 03 0 3 03 02 0 3 03 02 0 2 02 02 0 3 0.3 03 0 3 0 3 02 02 03 02 02 02 6 i □ 2 02 0 2 0.3 0 2 0.1 02 02 0 1 0 1 0 1 0 1 0 1 02 0 2 0 1 0 3 0 10 0 11 0 09 0 tfl 0 15 0 10 0 52 □ 62 0 72 0 73 0 75 0 74 071 0 76 0 82 082 0 83 0.8'- Cv 0 52 05 o« 0 44 0 42 0 36 0 36 0 35 0.33 0 34 0.32 □ 29 Sin 0 04 0 16 0i 0 29 0 63 -0 -0 1 -0 0 02 03 □ 31 OOH Mai 09 ■2 t2 13 14 0.9 0& 0.9 09 11 10 09 Ifai 01 ai 01 01 01 01 01 01 01 01 01 01 Water Works Design & Supervision Enterprise In Association wills Intercontinental Consultants and Technocrats Pvt Ltd.Af}d Ltdes.,4 Imgatmn Project Meteorological and Hydro topical Aspects 09- Sunshine Duration at Bedel e Station Jin hrsj<lay> __________ tear Jan Fcd Ma^ Apr Maj Jun Jul Aug Sep oct Nov . ----------- — --— — F Dec 1MT 7 2 6 9 a 5 5 6 6 6 3 5 7 8 4 8 8 3 8 3 «W8 7 1 6 5 8 2 7 9 6 4 2 6 4 2 5 1 9 7 9 5 8 5 0 2 79 7 9 7 4 6 3H 5 1 65 7 9 6 6 6 4 ’990 8 9 56 7 7 54 82 6 4 3 8 4 8 6 9.6 H 7 9 1991 79 B 1 58 6 3 7 1 •4 5 2 7 3 4 5.9 e ti 4 7 194? 5 7 7 7 7 1 8 3 6 1 3 4 2 2 6 7 62 6 2 8 3 19U 76 66 75 55 19&4 7 7 7 5 77 7 6 ■ 2 4 3 4 SB 9 5 94 9 3 1995 6 8 66 7 7 66 r •B ■ ■ ■ ■ n • Wj ■ ■ 79 •B ■B ■■ 3? 4 3 6 7 9 7 9 78 -997 7.2 92 7 5 ca 7 6 i 4 1 4 6 e 4 7 ft fi 7 83 1998 7 5 7 7 54 6 7 6 4 6 7 29 3 3 4 7 5 4 84 92 1999 8 1 9 1 88 76 76 6 6 3 5 4 6 66 58 9B 2000 9 B8 9 6 1 7 8 e ■ • 5 5 b 4 ■■ • 2001 ■ 2002 ■■ 82 7 5 91 84 6 1 5 6 3 1 6 9 98 8 3 7 5 2005 79 86 7 3 8 0 96 5 7 2 9 36 6 i 9.5 0 7 8 6 200 - 7 5 79 6 5 7 7 -5 4 3 4 2 4 5 3 5 8 2 8 3 7 7 tJj 76 75 73 70 6 1 3 7 4 F 62 7 9 8 3 8 7 |-5 ta wt L[iAl)(>Dedsssa Irrigation PrOjtct Meteorological and Hydrological Aspects Annex E. Hydrological Data M*y zoo? El S No Lisi Pf Sciectta Hydrological Observation Stations Staliun No. J ------- =- Slatton Name ____ Latitude. N Lonflitude. t Dag Min- D#g. Min. Catch. Area 1 (km ) 1 114001 OttdhKtSB near Aqd OB 41 36 25 9961 2 114002 Angar near Nekemi 1 09 30 36 35 1------Za. 3742 3 114006 Osoana near Abas ma 09 02 I 36 03 2BB1 J---- =— Period 4i yhruairzu.fjf1ir-vi 4 i n1fiyAgf.f■l'siUnUri*d. ■4 rhfi 'Ti i DR.4 iyoz ij”4 ■4 rtfin "ann^ lyyy-^uuj « 1140G7 Angar near Gutin 2S 5 114DOB Yetou al Yaou p------ 1 07’ 43 36 1*-- - 42 —_■— 6 114009 Urgessa near Genroe 07 50 38 3S 19 19 ry-Zu'jM 47 1y79-d£UU4 4 r=iT-fi TiFIAlI 7 114013 DaDana near Bunno BedeHe CM 24 36 17 .--- 47 1904-2003 a 1140'4 Dedessa near Dembi (ToDa) 08 03 —1 27 1606 375 __ —------- 4 r-i*£ 19E5-2UDJ J lJT.rTi'"3 s 114016 LOKO near Nekernt 09 22 36 36 - 10 114019 Temssa near Agarc 07 51 .. 36 — 35 47 5 1997-20O4 1989-2004 ii 113004 Melke near Guder 08 51 37 44 38 1998.2004 12 1:3038 meins near Guder OB 56 37 45 111 —JL 1966-2004 IS 101006 Jka ai Uh a □8 10 35 22 52 5 1980-2004 14 Q9100B Gilgeignibe near Asendabc 07 45 37 11 2966 1967-2004 ' 15 09’312 Gojeb near Sne&e d 25 36 23 3677 1970-2004 L Water Works Design & Supervision Enterprise In AMMilttoa with ]niereonilneni>L Coniuliants and Technocrat Pvt LtdArjo Dedessa irrigation Project Meteorological and Hydrological Aspects Annex E2 Mean Monthly Streamflow at Dedwan near Arjo Station i Million m3) May 2007 Tear Jan Feb j Mar ] Apr j M*y 1. Se£ Nov Oec ■ 1054 1124- - ■ s 51 5 44 0 37 5 94 9 65 6 286 1176 1613 1503 1304 280 581 3*1 29 B 28 4- 622 930 1170 855 107 19 3 179 42 7 147 1 324 672 1370 1040 374 184 38 2 ‘ 54 9 230 1049 1301 1178 1337 205 55 4 253 164 47 8 27 8 168 834 1051 665 957 320 71 0 63 4 57 7 74 1 62 5- 857 1086 1212- • - 22 7 20 4 708 1.2*8 1201 1260 459 96 0 52 9 21 4 a - W "IB 50 9 46 7 67 1 39 7 732 349 956 T421 944 291 89 34 l - 45 3 288 929- - - 181 177 5 55 9 170 3 73 e. 157-5 210 4i 88 T 4*2 62 1 37 0 16 4 10 9 12 5 53 5 241 *23 1175 949 752 304 105 3 52 4 29* 25 9 112 196 35 7 56 4 118 003 1237 719 209 117 4 7 63 109 3 250- * 1401 592 149 52 5 64 8 36 5 16 2 14 4 9 1 93 7 261 641 *278 119 48 9 24 5 21 9 11 5- - - •48 3 37 8 24 7* b » 25 9 55 5 20 1 l* 1 12 7 - 12 4 80 1- - - - - 151 *w 324 89 5 128 7 - - 1979 19&C 190' 1982 22 9 46 4 130 513 625 819 262 94 180 153 mo 6*6 1909 504 914 1288 1244 393 103 80 0 43 4 433 35 4 53 7 53- - * - - 59 8 ID 2 26 6 19 3 45 7 248 707 947 692 761 177 94 1%3 43 4 31 7 34 1 23 3 524 151 566 1119 1116 1231 265 121 3 i9fM 38 5 167 119 95 26 6 185 703 665 521 131- 1905 1986 1W7 19BB 1981? 1990 1991 1992 1993 120 54 2 5 n 8 62 4 169 438 927 842 260 79 45 0 176 9 5 16 1 13 8 12 B H9 452 494 732 222- no 59 124 17 3 36 7- - 673 388 160 era 5 4D5 27 5 21 6 7 7 37 a 2BC 555 • *■ - 189 233 20 4 33 5 27 1 121 273 439 1QB7- 107 123 1 53 5 300 338 60.9 42 0 157 343- * -■ --■ 543 1143- ■ * 24 5 23 9 i3B 20 7 565 161 368 824 564 806 164 38 1 73 4 42 5 27 9 24 4 54 7 1052 3l2 600 1159 631 4Q7 177 63 3 19.1 196 15.5 ■ 57 59 7 220 534 1221 056 156 58 36 A Water Works Design &. Supervision Enterprise In ASSCtiaiion with IniertontmentaJ Consultants and Technocrats Pvt. Ltd.Mn a«k« [mfj-jui hujen Mei&ortj Irinin nd Hydrolpgicai Aspects UJUl l £2; /.... Continued) L^ Jin Ftb 'Mar Aof JU tv Jun Jul r ' ;a uq Sep JOgI k&u |C tec 1995 l^T ltefl 1999 2000 2001 2002 2003 200 MM 122 MjB t9 4 38 3 as 225 569 466 iW gQ ■ *- 41 4 ■g o- 304 14? 8 373 723 654 598 87 2 - f -* >- _ ■■ *■ T - * - - ■ - 242 1357 B5 i 59 5 «■ 57 2 126 3 401 740 1W5 1005 6?4 215 mi ? 99 0 57 2 55 3 63 4 46 2 >75 457 55? 575 211 115 __ Jr 83 * 362 552 74 3 120- «2- -- 521 40 2 30 3 26? 65 2 202 Sffi 639 543 536 140- <nr CV S>#w 462 217 260 33.2 66.5 223 654 1007 389 581 177 909 0.4? 0.52 0 66 0 71 0 59 0 46 0 34 0 30 0.32 0 68 □ 51 0 50 0 66 0.6$ 1 14 0.54 1 M 0 74 0.22 -0 16 0 43 073 1_2fi 1,00 Mi- 990 63 4 67 1 94 9 190 9 503 5 1176 1 1612 8 15025 1337 4 459 2 210 4 W.in 12 0 54 2 6 63 12.6 53.2 225 0 49? 1 <a$.g 130 8 599 Mean annual flow « 1821 Mm3) Water Warks Beslpi i Supervision Enterprise Id AnomUMl Witt IblEKDQttltDOt CCBSultajiu ind TectkuDtnu Pvt Lui.<n-n Dedttta Irrljratnin Project Meteorological and Hydrologies Ms pects Efc 41 Mtan Monthly Stream Ilaw *t Oedcssafi near tMmbl Station 2O0" ( Million mji ____ —.———i——--------------- fear Jan Feb Mar i Aof Mnw ■■ —T" Jun Jul Aug s-e Oct 1 Nair pec 19B6 1967 i960 1909 1900 1991 199? 1993 199a 1995 1996 1997 1990 1939 2000 2OOi 2M2 2003 2004 fid 3 7 ■i 2 7 0 25 0 92 @3 1W 302 2T2 ?02 21 9 85 5.5 9 7 04 9> 4 50 262 2M 299 67 22 9 11 5 5 9 4 5 9 7 9 2 10 6 105 243 342 218 ’04 44 1 27 1 17.9 157 12 5 64 23 9 153 217 392 4B9 147 52 0 18 0 11 9 76 4 5 11 5 Bi 31 1&7 253 272 142 24 0 13 E 10 3 58 56 22 r 90 52 252 5454 362 126 20 9 9 4 72 6 3 56 12 5 29 5 76 305 622 263 14Q 13 4 6 ? 7fi 153 12 0 8 8 366 70 136 269 103 71£i 45.? 17 1 11 2 17 2 156 3? 6 80S 252 334 370 204 11D 40 7 nd 7 1.2 3 13.5 160 22 5 37B n2 274 361 202 S9 30 5 16 4 129 12 1 15 5 23 B 48 7 07 >90 272 331 101 32 5 33 7 129 94 15 5 23B 48 5 07 IM 272 331 101 32 S 33 7 2i 2 13 8 23 2 30 i 552 >42 219 34 J 2CM 262 55 1 2B 1 136 ?D 3 12 7 3T 1 no ?72 415 595 329 880 21 l 130 55 6 3 9 5 54 9 14B 242 245 214 302 40 4 10 3 10 2 56 4 5 9 7 41 2 119 290 309 242 209 92 0 21 3 12 7 9 6 11 2 14 5 55 5 22B 330 322 295 212 59 fi 22 5 6 5 6 9 66 90 65 63 t’92 255 195 60 27 7 14.19 7 4 4 a 92 24 0 57 59 241 223 324 62 20 3 10 01 13 O 1.3 0 13 7 33 0 95 5 19* 206 208 145 39 IB a 10 0 Avrrjgc icv $*aw WAX Slftn 122 £47 TT 5 16.9 36 4 T»2 4 232 4 3569 273 ?54S 404 20 5 0-17 0 4£ <?48 0 56 G 69 0.526 0.27 □ 326 0 20 0 561 0 81 0.53 s 35 0 3F G47 OUT 0 85 1 020 -0 47 0 927 0.89 0 658 26 1 96 2fi T 172 23 2 37 6 98.5 252 334 554 403 329 107 9 56 1 5.9 3.7 42 64 6 5 31 93 165 F45 39 13 4 89 Me»n annuls flow = 1l5S_Mm3i Water Works Design k Supervision Enterprise H9 to unnu)u wti mt,„„„„„„ CoK<ll,„H rXoema Ltd.irjft&Nltsui i motion Projeci Meteorological and Hydrologic*!^ P E4: Annual Maximum Floods linnOsi May 2W" S PC1 - PtM-JESJ I n-r1-i oe*r rat J J SMI&e r'**r nrQe^rirr 4,n jr HToJr GuM ? Fear DWHl flpjr -J ».-U JltJf Of-m-liir .giensMrao _________ 1 633 1173 m 789 BSC 951 814 1165 78' 213 206 21? 243 354 226 20D 151 109 262 i&4 175 226 175 211 244 271 300 370 267 467 151 2 198 3 130 330 132 272 173 127 159 25fl 2^1 217 4 5 6 7 a 231 1?fl 264 15’ 167 205 ne 335 3fil 2M 247 25fl 157 27i 252 9 434 440 10 11 634 247 339 105 136 284 214 140 249 177 288 138 536 721 196 297 12 13- 14 15 IB 257 <56 129 ■4B 151 223 49U ■50 135 314 143 119 17 645 554 1063 360 480 502 341 236 202 248 92 9C 127 143 314 184 150 203 226 132 245 366 574 771 85 121 104 12a 14’ 73 S& 124 137 134 105 125 142 135 T 42 149 1 70 172 109 106 79 iai 120 16* 750 247 56 105 261 646 804 1134 353 525 525 192 237 153 744 312 EOi 255 100 174 150 282 132 193 199 439 236 Witer Works design Supervision Enterorlse In A^dittaD WLLT1 iDtWWmiifflt!] Cnn^luncs and TKhMtntt Frt. Ufl.E5 MeJisurod 5edim«M Conretilialien At Gufflira Gauging Station No Field stirr.ple Nn I ab No Rivnr Stream Sl.il ion Dale 4 Time of Sampling 1 uric i.Secj CV heigh irrt‘i Flow imVt] Depth mi W*dlh Irtlj Sediment Concen mg/ll Hrrn.iifcs AV 4H4 J 495 2 4Afi 3 604 1 66$ 2 666 3 1057 1 1056 2 1059 3 1190 1 1m 2 1192 3 I 1223 1 | 1724 2 1225 3 1 2696 1 1 2699 2 1 2700 3 I 2704 1 J 2?05 2 2706 3 Dertess-a Toba 15 Mai 90 0 43 4 16 0 26 Dcctess-J T oba 15-Mai 90 0 43 4 10 0 70 B 9ti 51 56 13 rl 40 00 Dedessa Tuba 15 Mai -90 0 43 4 16 0 36 Dride&sa 1 oba 21 Mar-90 0 50 5 41 0 54 Dedessa Toba 21 Mar-90 0 50 541 0 60 Dedes$a 1 oba 21 Moi-90 0 50 541 0 39 Oednssa Toba 2-JUI-90 1 fll 9 14 fl 40 D*(tassa Toba ? Jul-90 t ai 9 14 fl 00 Dedessa lota 2-Jul-9D 1 61 Decfossa 1 oba 22 Dec 90 50 0 40 Dedcss a Toba 72-Dec. 90 50 0 40 Dedessa Toha 22 Dac-9<1 50 0 40 Dudessa Toba 18 Sep-90 Dndessa Toba IB-Sep 90 Oedesss Toba 18 Sep-90 2 46 2 46 2 46 9 14 7 no 4 37 0 43 4 37 0 74 4 37 0 46 98 50 90 50 96 50 20 ? 70 14 0 61 66 13 3 19 9 70 14 0 21 0 Dedessa 7btja 16-May-93 45 0 46 Dedessa Toba 16-May 93 45 0 46 Dedessa Toba 16 May 93 40 046 2 59 0 66 2 89 061 2 69 0 71 19 5 65 13 0 42 fll 59 69 173 13 90 63 215 31 135 G? 190 00 90 94 99 37 63 13 141 56 187 B2 124 69 87 90 108 63 81 40 Dedessa Toba 1?-Apr-93 0 64 8 01 73 05 64 61 Dedessa Toba l2Apr-93 064 a oi ______ Dqdessa Toba 12 Apr 93 - 61 59 0 64 a oi 59 20 Water Works Design & Supervision Enterprise In JssoclaUan with Inwreontinenfa] Consultanti and Technocrats, Pvt LidMeleorological and Hydrological Aspects ikjij CiiniJ' F5 No cortf/fluedl Field sample No Lab No R>vor 1 SlicAffl Station Diilc A lime of Sampling lime iSec} G/beight iml Frow im>l Depth tm) Width .w Scdimeiil Concen Remarks (mgi) AV 541 1 179/04 Dedes&a Arp 10 Aug U4 30 2 45 54? 2 M3 3 De-dessa Arjo tO Aug-04 26 245 Dedessa Arjci 10 Aug 04 20 2 45 544 1 ian.'O4 Dedessa Arjn 11-Aug 04 32 2 56 545 2 Dedassa AijO 11-Aug-04 20 2 56 546 3 Dedessa Arjo 11 Aug 04 27 2 56 559 1 185/04 Dedessa Afjo 1 Sep 04 29 361 143 12 9 05fl 17 5 143 12 9 111 35 0 143 12 956 52 5 196 11 11ft 1BO 196 11 9 6fl 36 0 196 11 9 6f1 54 D 611 23 13711 18 0 1417 50 1739 74 1740 74 1652 06 1718 12 1639 31 1360.22 560 2 Dedessa Arjo 1-Sep-04 26 3 61 611 23 14 3R 37 0 1326 Bl 561 3 Dedessa Arjo 1-Sep-04 29 361 611 23 1 460 55 1438 44 142 Water Works Design & Supervision Enterprise In Asfioclatlon wilb Intercontinental Consultants and Technocrats Pvt. LtdAnnexure - 8 HYDROGEOLOGICAL STUDIESHjdrpgeptogjcsJ LnvestigatKui^ TABLE OF CONTENTS I*faLL OF CONTENTS_________ ______ LISTOF FABLES------------ ------- LIST OF FIGURES 1 ISTKODICTIOA __________ l 1 GJhl^al T J LOCiH£» TJ Pmyshkhapxv 1 .* Ml TXCrtXjL W AND 1fJ**CuUME5 1 PHI MGU HYDROGEOLOGY —... 2.1 HtaftOG4flH.i>&CJU-SETUP 2.2 Hrra»«6<X0CiC IMH 2 2 i FfKfurfliP anchor MfltfMratf ygtolM 2 ? J Affvrt?/ 2 2.3 Df R/■‘*3* ■Zfltfi'i'TNlinfS 2 J INVEnTMt and AEll DATA 2.4 HI*DRDDTMAifrC FaRAMETTHB <X aQuifERS . .. I !■■ .«... „ - J. M. I I II I! ff—T—T B . - . . . . Mi a U. fi I I ■ rrc - ■ ' T-GROl'WMb aTEK POTENTIAL-..—.™™—........................ 3.1 GROuhDWaTEB RECHARGE ESTIMATION J. 1 T Sfl'ia iTo* arttfJ/JrS 3.t 2 WBrar ftatoME ■A- W Al 4R Qj! L A L.l FY —aai—u I.aa-J,1 M ua,i,aj —TTTwrrn-rrrBT—1 U-Jx"* r?—Tr—“u“u “11 4.ii Water samples 4_2 SaWPUNG TECHNIQUES *NS ANALYSIS 4 J PHI TOfflAi. REPRESCNT*no«s Off WATER QUALITY ANAL^S-S ■I 3 i P^wf diaflfBm 4 3 2 SOwWflf (fraffTTiny ■f J J ST'fl tfrapra.TT _______________-_________ ._____ ....a................................. 4.4 AflftlCVLTufeAlJWBiiGATlON WATER QUALITY 5. PIEZOMETERS OBSERVATION WELLS AND W ELL FILED . .J1.11Ja.a_ .. _ 5.1 Eh 5 TRI ft im on DP PiEZOMETERS-’ObSEHY ATIOH WELLS S_2 Future we ll held 4, WaTER LOGGING AND DRAINAGE_________ _____ 6 1 TCPOGRAP MC FEATURES AND SOIL CHARACTERISTICS ■B J Existing wQuHCnwiTg r table 4.3 Future grguhcnvatea table and rechabge prom irwgatiom J. SaLIN IT1 AND SO Diccn —----------------- ™—____________________________ __ L EXStTING AND FLT1RE PROSPECT OF GROUNDW ATER__________ I i Existing grgundwateh development 3.2 Future grouncw ater Psosf’tcT Witcr Works Design L Supennsinn Enterprise la AiBHkaEkii m iHCerMDUMnat MMkQQ ABd TecUBocrtu Pvt Lid.4r)o Oedun lnrtc*tJ« Project Hydrogeological investigations Blay 2007 LIST OF TABLES Tatxe 2 J Details of boreholes m tne study area............... ........... ........ Table 3.1 Monthly local flow and Minrmum fk>w of Dedessa over near Arjo Table < 1 SAR and EC values in terms of irrigation water suability Table 4 2 SAR and EC values for surface and groundwater in Arjo-Dedessa area ... . Tab*e 5. i Locations of the Proposed Piezometers Table 6 t Annual gross crop waler requirement at primary canal head Table 6 2 Estimation of wetted area for Arjo- Dedessa irrigation canal Table 6 3 Seepage ios$ from unhned Arjo- Oedessa irrigation canal LIST OF FIGURES c igure i 1 Location map of Arjo- DeOessa irrigation project Figure 1.2 A map showing J- D view of Decessa over Catcnmenl....................................... .......... Figure 2 i A map showing nyorogeotogic units of Deaessa river cathmeru Figure 4 1 Location of water sample points Figure 4 2 Piper Trthnear Diagram tor Water Samples Figure 4 3 Scnoeiier diagram for water samples .. IIIRI I I 41 I I lit Bl IB IBBI I B■BB 11 IIIIH * IBM ■ HBM I • Figure 4 4 Stiff diagram for water samples............................................................ Figure 4 5 Electncai conductivity (EC) in psrcm ano Total Dissolved Solids (TDS, in htg/L for............................................................................................................ Figure 4 6a Map Showing Contour for TDS Figure 5 1 Proposed Piezometers/Ooservation wells Figure 6 4 Profiles along different lines in the command ar',er“ a Figure 6.2 A map snowing lines of profiles in the command area Figure 8 1 A map showing groundwater potential areas ............. ■--••• Miuri 11 i . ... . .... . . _ _ _ ...................... ......... | Water Works Design & Supervision Enterprise la UMcfcttoo nth (MertohUMataJ ComuUmu a d T^bnocrau, Pvt Ltd C*no dmbu* rmr«j»n Project BytlrogeoJogtcai Investigations 1 INTRODUCTION 1.1 General: Hyarogeoiogy refers io me occurrence, movement. chetrialry (qualify), etc of grou m general it nas a diversified apprication in developing, utilizing and ma ' g 9 Half 2007 3 study and design of the pr^ct According th.s sttrij at Feas.bility Stody lecel has been undertaken Water Works Design & Supervision Enterprise tn A>«euaoti with loT.rHnflBwixl Cwiultaata d Tec tnotrvu Pn Ltd groundwater Furthermore, different aspects of groundwater such as recharge drscna g condition. aquifer type and set up, its interaction rmlh surface waler, elc are treated (his discipline The nature of groundwaler and now il behaves, when subjected to natu man-maoe activities r$ studied for different purposes such as for water supply ido agnculture and industry j and construction of surface and sub surface engmeenng structures teg., dam, tunnels, drainages, etc). In order Io develop and manage groundwaiei one has 1c know its potential, qualify and movement Etnioptff nas diversified nyorogeoiogical icatures mat are attributed to ils geocogy structure hydrometeorology, topography, eic The hydrogeology of me country has noi been studied rhorougn.y so rar With the exception of few areas such as Rift valfey mai has oeen mapped al scaw of 1.25C 000, the country rias only small scate (1.2,000.000) hydrogeological map Mydrogeckogy >5 usually applied for locating borehole sites in light of water supply Groundwater has been usee without oecail understanding of the resource In spate of ample groundwater resources 01 the country very little been studied and used so far Currently however ncrt only grounowsTer development anaror utilization but also rts management es gertma an attention Smce any development relies generally on proper utilization of natural resources, the gavemmeni has also given locus on water resource development both for domestic water supply and irrigation As part of this water resource development. Integrated Master Plan Study ot various Rrver basms nas been undertaken in Ihe country since some years The Abay Rwer basin is one of them Arp-Detfessa irrigation project has been identified as one of the projects during "he Aoay River Basin Master Plan study rtydrogeok^l mvestigaHon and study that mainly focuses on groundwater occurrence mo^manl, ChMtofy. etc ha Men incluow as one of the components of the feasibtlHy Arjfl Dedttii LrTtfiUcn ^reject Hydrogeological investigations 12 Location Mty 2007 The project area is located within Dedessa River suobasm vrbich ifr in turn located m Abay River Dasm. it is within the Western Oromia National Regional State, particularly at m junction of East woUega. Iluoabor and Jimg zones. Toe sub oasm of the irrigation' project is bodBreu oyQmo-Gibe River basin on eastern side and Sara Akobo River ba»n on SW 3MJe The total area of the catchment al the proposed dam is about 5,632.Mk*t The project location is shown in Fig l 1 The project arBa can be reached from Addis Ababa through two alternative hign ways that take either to Sedeie or Nek&mt. The all- weather gravel road lhat lanes from Nekemt to Bedeie passes through 1he project area. Hence, in general the project area is about 480km from Aodis Aoaoa through Jima and Bedeie 2uof^Auti d»u> wqjjwf j-i flyArjoDfdtsii |rri£*a»a PtoJmi Hydrogeological investigations May 2007 GerJessa river caicnment rs shown in Fig 1 2 1 4 Methodology and approaches in order to unoenake it* hydrogeoigoicai. etvesugeiiDn of A/jo-Dedessa imgabon profect area, (he tolldwing meffwtWtogy and approaches have Deen used: • Reviewing of tntr previous works and oats available with different institutions such as MoWR, institute of Geological Survey, Regional Water Resources Bureau and Offices Regional Water Works Construction Enterpnses. • Feld survey to collect primary information on georogy.. hydrogeology, geomorphology, ano other physical features of the area • Preparations rn inventory for water supply schemes and fixing their location with GPS measurement oi water level for wells, estimation of discharge for spnngs. water sampling Horn spnngs. wells and streams/rivers for physicochemical analysis • merpretaiion of aenai pnotos. satellite images and Topo maps (1 50.000 a 1 250,000); appucanons of various GlS and remote sensing software to identify and oel neale uthoiOgy and geological structures, and finally to analyze, ana compile the 5patia> cats, and tc incorporate them as maps Tor various themes. * m-situ measurement of pnysicai parameters of water quality indicators Uy using field water quality lesl kits (Ph. EC. TDS and Temperature meter) * F.ngly, preparations of hyoroqeoiocical marw umi-h based -an all che collected ana a^aiyzea data ____ _..________. 4Fig. 1-2 4 map s/ioidng 3-D rfew of Dedessa rivtf catchmentArjo Uedtut JrrlfuJon Project M»y w; Hydrogeological investigations 2. PHYSICAL HYDROGEOLOGY 2 1 Hydrogeological setup Ike .n w.oanc ».» flows ™.nry ».*»»> V—«’ MS Mm(mes s “ ’"''’‘““7 W. on Jo. ». „ We r as on LuOnoo- and «o«ga Sa>.o. W <*"=">> • "*"* ca“,,'c lava row e.ew wilPm ta Oeoossa River »*» ^erB OU,C",,, " MseTO„, or vanoaa 9,annas. sasses ano pogmawe The veloan.e rooks on Jima s.de »» r.1.oM ,o as Lovv.r pan or Jim. WHoWe. comping Pood Oasalr with ana sakes on the wesiem, soaihwestem. eastern and sooiheasrem pan or me over carciimeol. vspe > on the nigh land However at Iho lowland pan or the calorene nt along the Oedessa River, lhe outcrop <s referred Id as Alghe group comprising biotite and horn blende gne sses. granulite ana migmatite w>1h minor Meta-sedimentary gneisses The '/oicarucs are* 05 Laie Eocene1* Lat& Ohgoccne ag&, whsre as the gneisses are of Arcnean age Tne volcanic rocks (bawfoc lava flow) m Bedeie area is referred to as Mflkonnen basalt cumpnsing flood basalts di directly owftrltes Lhe orystaUina oasamem that snows me jncontormatite relation for the two outcrops. Il is Ohgocene-Miocene age ^mitarly. Aro area is compnsed By such flood basalts ol 1he so-called Mawonnen basah BasEd on tne investigations made m the area, variduS aquifer set up exist The main aquifers are weainered and /or fractured basaltic lava flows and other acidic volcanic rocxs such as rhyolite and ignimbrite The aquifers of volcanic origin have ooth confined and jnconf«ned character; for example the volcanic rocks in Agaro area shew both characters The confining layer in this particular area is highly weathered volcanic ash of clay size as reveaeo from existing well drillrig data There are aquifers that are attributed to sediments especially alluvial sediments along river valley and streams, and colluvial sediments near mounwms and escarpment in addition to these, there are also minor aquifers attributed to wealheren Dasemonl rocks tgranrtes and granitic pegmatatiles) This iast aquifer types nave hl*le significance m the area due to their limited areal extern and limited aquifer productivity T hc presBras of thermal springs, cold groundwater ana ratine springs m the area shows the o^rsrficalion o' the hydrogeotogitai set up of the nver catchment The aquifers of sediment ano wwinerea basement rem origin are un confined. In i aadi Jon to (he (i ,logical Wafer Worts Design & Supervision Enterprise la AS3«iatjoa m bnmoMkHini Comhua 1Bd T«inocr>ti pvl lwArjo tofan IrrwuM Prnjrci Hydrog ec i HjficaJ Lei .mtig auons , ma if W hinder ’*"* Wrthift Dedessa River valley, deep £*nerra1ro<n of grou - underlying massive basement crystalline FOCfcB e*c*P .^ th*v are contfOiBa E-'j ro geixogHLal structures as revealed by ttw presence -•■ ?r,Hr 1|-1- , r r -* The volcanic ash a nd clay fonn th* confining taysr W w at^-Ewarmg Aqurfer m Agaroarea can be menliofied as art exampte p'* *-' ■'l"lt' wearherea i fractured) enhanciMg me mfiliwion of preopiialxr grwuna^aiir recharge Groundwater recnirye m the area >5 «ry mammal due Io t r> ■ reasons, among them are the NQtl precipitation dense vegeialior co* J ■ve^lherec and or fractured volcanic lava IIomvs * The fin am groundwaler r echarge of (he area r$ the SE SW and the M E par a r he nr« calchmnni The pyroclastic flits of mannly voicamc ash uomposivon ts found al most pads o* the riYtr catchment such a-s m Setema and Aina-gv area The intercalations of (he votaanjc asft with fractured and/or weathered volcanic lava flows- GBuM the emergency o imart * 5E T.j5 in me river catchment of the area r However tne presences ot thermal springs with in the Dedessa fiver valley ire atTntvuted ■ma n v i geological structures, faults The physicochemical characteristics of (he frwma sprint;- mgniy vary from upsueam to uriwri stream along Dedessa River wrfhun (he proper are* Allhough it needs Further investigation to verify the physico-chemical vacation me long*- *e»xfence twne 0? rock-wilier interaction while groundwater hows trom upstream to □own \nt-am could be one possibk? reason The topography ol Che area along with lhe prevailing; hydro-metecroiogical conditions favors the tAisience of well demarcated grounowaier recharge and discharge area 2 2 Hydrogeotogic units Graundwalm occurrence mom and quality v» mamly governed 6y trre e^t.ng hyd^D^.c units The phrase hytogeotogte unit relers to the nscks (cwwoeoatw o unconsolHtaledi forming Lhe 1ran,B «,* for grouretwHwr Occurrence movement *r>i Wuer Works Desltn & Supervision Ltiifrprise lo mockttoo with laureourtaeoc., Cooiutusu ud Twhewrau Pvt L14 -Uwessi Imcidsa Project Hydrogeological investigations The hydrogeoicgic units m Dedessa nver catchment have Dfis^ catago following unds They have Deen shown on map available at Fig 2 1 discussed nere under m brief. 2.2.1 Fractured andfor weathered volcanrc rocks TM comprises basalbc lava ftows. acidic lava Kows and falls such as ig pyrociMbc falls In this category of hydrogeofogrc unit, secondary porosrt fractures produced due to weathenng and geological structures play immeasurao e comparea to the primary porasityrpermeaoilrty The areal coverage of »h«s hydrogeo°g unit r. Odessa nwr catcnmeni is 8.189 35 Kirf (79 56%). 2.2.2 Alluvial sediments As the name impba* these are c oncentraied along rivers and streams, and it comprises vancus sediments ranging in size Irom day through sand and gravel to pouid&rs The areal coverage of inis hydrogeologic unit in Dedessa river catchment is 1651 D5 Km (16.04% J 2,2.3 Delluvial sediments Tnese sediments bkisi at I ne t rendition zone irom the mountams/or piateaus 10 I he river valley They are aenved worn dawn siape moving earth materials Irom mountains mainly due to gravitational force From hydrogeological point of view. there are no as such demarcated properties between alluvial sediments and delluvials However, for Itie convenience Qi description, this hydrugeologic unit has Oeen described separately Delluvial sediments with m 1he project area have coverage of 452.91 Km (4 40 %). 2.3 Inventory and well data in order io undertake detailed investigation pl the groundwater of the area, waler supply schemes nave wen inventoried and their geographical locations have been identified using GPS Borehole data have been oolleaed for detailed analysis of hydrodynamic parameters thougr complete well date are not available m the area Same of the measurements that have been undertaken for water supply sources during the field Survey are physical parameters ot water quality by using field test tots such as TDS, PH and temperature meter Water Works Design & Supervision En terprlse 10 AlUCMti.. wtti taieretwtaeiteJ Consults tz d TwfcaotrW Pvt Ltd. J U*'J0 Defles“ Imfadon Project Hydrogeolog-jcat investigations 1,s * 2007 ln add-iion 10 thes* primary data. secondary data have atoo been collected on both water Qvaiily and other Well data. Satellite images and aerial photos nave been interpreted to •deniily geological struaures and other ithological boundary demarcation that have been venfieo py feia 2.4 Hycfrooynamjc parameters of aquifers As * nas oeen mentioned previously, the mam aquifers in Arjo-Dedessa project area are Irjctured a nd. or wealhered volcanic lava flows [basaltic and acidic lava flows I ano sediments alluvial and colluvial) The boreholes in the fractured volcanic rocks ano sedJnenLs are either with partial well data o< totally without well data Table 2 1 snows the Dorenotes drilled previously in lhe study area and their depths. Taoie 2. i Details or ooreho*es in the study area ho Weil ho PAi*village OopIFi SWL 1 wei t Metta 55 75 te 2 Wd2 Metta 43 4 12 3 We«3 Metta 43.5 17 4 HT-2 Oollc Sin 27 5 HT-6 Chdaio Bddima 72 "— ---------- • 6 HT-7 Chafe Anani 57 7 WCl T Chuli 62 1.3 a Wen 2 Chuli 41 — 17 5 Well 3 Chuli ’26 21 10 Well e ChuH 30 2.1 11 Wall 5 Chuli 25.5 1.5 "2 WellS —'■■■ ~ —i iJi Cnuli 42.5 22 13 Maea Talila SaKa«cna Brfiu 52 — 14 Iftu Brftu Baxaieha Bdtu 35 55 Water Works Design & Supervision Enterprise Id AssoaaUoD with LntercDDUnenuJ CobeuIcmw tnd TecboocrMts Kt Ltd. 9* 5f ‘ -* Moirfftj ft^rogvotugfc units of Arf^DrttssJ rtvf ctfctmonr Mcxm *r»i I / hma Arjn uIrja Otdtisn Lndcitlflc prgjert Hydrogeo logical Investigation* 3 GROUNDWATER POTENTIAL J t Groujiewater recharge estlmtrtioh May art? .r.™ to g ,puMwaB- ol an « >**- ' K ■W“l -w. « usu^ nW » pc gra—a®- «*«* "al 10 “ 1'n°“n G,!>“ -e^rgc « an «« can be ertmMed ™ •*>*— «•"*•»» *• °‘ approaches is through waler balance metnod In eroer to employ groenonate, WK1> estimation, the necessary Oslo n»»e been acquire for analysis In SU «»m.nta, to tlw msthot. Ms. flow analysis to. R.eer.'s«eam flow (DedWM R~W> nm. c™ tod.he.eh to det,™ some coefficnmts >or water ba.ance Hence. - ■>» ground water pQtenrtiai osiimston oi Oedessa River catchment ticin meintxi* e<*iO*Oytd m order to come up with concreie result as much as possible 3.1.1 Base flow analysis in onaer to employ case lbw analysis approach f<M groundwater recharge estimation. the rawMhi} discharge or Dedessa River from 1961 - 2002 for a total of 15 years have been jsed. The nver flow aala -s not consecutive aue la some missing dale tew some years AccDrWigly the mean monthly minimum flow of Arjo-Dedessa on annual base is shown m TalMe 3 i The diHerence between 1he total flew and the Minimum monthly flow is supposed to be lhe surface runoh Accordingly The surface runoff For Dedessa nver catchment at the gauged statin is 1.105,7 96. 874 m’ Where as the icnal minimum monthly flow of lhe river is 1,5ra.W2,93B m3 as shown in the TatJte 3 1 The basic assumption in deriving groundwater recharge from oase how analysis r? that She monthly minimum stream discharge ■§ equal io ine base tow This approach has Uefln menUpncg fay Wundt (197«) 1bSl the monthly rr nimum WMffi discnarg* Bost appreciates W base flow, especially Tor tipimd Climate Tnaralom the base flow that l3 supposed to Correia tQ 1 b» gr^Mwater ™arqe.S round IP be i9t 6mm. This value is oMamK by dividing I.SGZ.Q^.asBm3 py the area erf (he gauged CBChnwnU, wt^ ta SjftW Th.s arnpunl of gropnd water ,echl3rge ,s Water Works Design Supervise Enierttrd^ ^------------------ “ t - in rntb lutErcgwiaea^ c01nituB[a Md t«L™ on LU. IIArj o Drfessi LrTljfatlaj) Project BydnogeoJogical Invtstigadons minima. as it amounts to only aooui 13 oj% oi *hnzh is ■452.9mm Miy SOOT 11 53% of tne total 0Anual pfecjprtaiioo of me a Furms.mo.e oases on the same method (he surface runoff ol me Rtve m teen „ toe strferenee Oetzen toe .«.( ™=- 1(0. on annua, ease ano woras out to Thft ■■aive <5 used to derive the run off coefficient surface r un o111 Of She e nlire D edessa c atchment t o- D—» * .n— m> ma> * a.tr.bated to so w -n. the river catchrrisnl to asses tne i ce ha an 11 usftd in the water c glance approach al 1he groundwater recharge estimation m the next section. Tabtt 3 1 Monthly total now and Mmimtxn flow c4 Deoessa nver near Aqo Parameters a,, _________ Difference —T-r-r—--- .aIj *—ak Months M'Tm c MJ?month Mbiec Mf month M vse c Pfl ^niUHILM _____ 1 J - ■ IM 47238046 4 473 11SBW8.3 13 16 352575<i5 "F 12 4 ^934209 M 1Q44 279’3SZ4 2^ owe 5443200 13 is. i 24 551Q0P ] 2$87»4 9 48 _ 253^3-89 A ’ 5 54 4052730? 4 557 118117*4 11 OH 25 715556 M 7SJ52326 10 3fr* Z77sesM IB 76 50293386 J J 47 2SS23&5J2 45.433 11775233$ 53 04 137424496 J 75J 3? 7Q54O8&5B 137 385 367&1B416 126 A 423 i’3406W26 220 Gdz 590394317 202 74 33?*9O5*2 5*3G447Cft s 6? H-9’ l&igei 217 777 5454477954 126.C6 326713997] 0 2ifl.67 5sStii7513 58 377 156356957 150.3 429340555 ------- B 66.32 177074554 .26 258 58004736 42 06 10901 i&iO 0 35 65 954E-5139 13 7W 369*0*93. 31 4* 58544646 □ad m J 4,Q5T.M».»11__________________ 1,»62,OT3 »3B 4 2,105,796,874 Q, = tulji rfior-lhiy d^charpe |nv), MiH Q = Mtnimum mgnihly tfi^ch^rge | M' ‘S) Ditf * difle^ence MTWeen I he MUl rngnlhlv diS£Harge 3.1 2 Water balance method By *uier Balance it <s meant equating or balancing the amount □( water inflowing ano out flowing 1or a given sysiem. such as hydrogeoiogic system, over a given duration for a given area hence i s a a ynamic s ystem, ( Detay 1997) The nydrogeologic s y^tem c an be a dra.nage oasm/oc catch mem. groundwater basin* soil layer, or any surface water reservoir naLurai or artificial) waler oaionce « a vaiuaoie too. tn tne 7tn y al S s 0 water ,| in a reglOn The mol hoc on oe employed for different purposes compulation of groundwater recharge, evapo- Water Works Design & Supervision Enterprise Id Associating wicb lutertOBUieaiii CrmuttMti fcad TacHbochi* PtL Ud 12Mo Dedcssa lrrt£ lUOtt fttject Hydrogeological investigations Uay SflO' Cycle Lecooio and Dunne. 19?B t gmundwaier The basic equation of waler balance is trrllow = outflow +£bS Where aS i$ cnange m storage For ihv siuOy area, the mam rrfftaw component is precipitation, but the outflow components are evapotranspiration ana surface runoff assuming all other components such as water aostracl»an Dy human for other purposes to be negligible Besides this, the change in storage can be ccnsidereo to be zero if the water Balance rs made by taking waler year .'or hydrologic year Hence. 1he ■/slue of AS will be negligible^ zero smoe the calculation is lo be maoe on annual basis Since ramiail record can be obtained from meteorological stations in the area the mam 135k left is to e&iimaie /or calculate me potential ewapo-iranspLralion from which lhe Actual Evapotranspiration 1AET1 can be derived tor the catchment. In addition 10 this. the surface runoh has aiw to oe esUmaled-'or caicuialeo since there is no actual measurement of this component in the stuay area. P*e surface rundl rcr Aip- Dedessa nver cawbrTrenl has been denvad (estimaied) as tallows over land flo* from which 'he runoff coefficeni, Re. is caicuialeoa D = ovenana ftow = 2.105,796iB74 m P = annual precipdatiDri -1452.9 rnm 1 452m A = fl/ainage area = t.M, ™ 000 rflOOMW alalron Bui this hoes not nwn lhai Ina total drainage area o1 The studied t>. rfencs Rc = 2.105 796.B74 m’fl 4529 m * 9.9B1.000.000 m' " This Runoff poeffioeni is used w estimate the surface runoff ’<x th* nv*r bas'n |OedeSSa Rrvwi under study in order io eswnate the surface runoff of Odessa area, the mean annual precipitation 1452 Sown nas bean used rience w surface ^unott lor the entire Ded&ssa River catchment becomes 0 1452 X 1 452<n X 10.293,303.358 QB m2 = 2 170,141.254 31 ma Thus the surface runoff wcxKs r oui 1c 2*O.B3mm Thu ^aiue ■$ only about 14 51% of the icrtai annual precipitation m I he area Note that the total arsa of me studied rwer catchment at the out Jet of (he command area U 10.293.303 358 0S m® By assuming the coincidence ol groundwater oasm with that of surface waler divide and ano by assuming that mere rs no artificial or natural mcra-oasin subsurface or surface flow, the grourawater recnarge of Dedessa nver catchment can tw estimated as follows GWr = P - '.Sr * AET; rotate Gro-= Groundwater reenarge P = Annual prBcrprta1ron= 1452.9mm AET ■' Actual E ^apo-trartsp*nation Sr = Surface runoff = 21O.B3mm Tnfl Actual Evapotranspiration. {AET) can tie estimated based on different melhods one ol * » me emp.rlCfl( Turc method TurC method ,s represent by me foiling formula am Dtdrssa Lrrigiuirt Project HydrogeoJ ogical investigations Rc = OTP A Where Rc Runoff coefficienl Maj 2D07 Waier Works Deslpi & Supervision Enterprise tn Ablation wiui l.i,re0QtlBH11Lli CramJu-ts Tw.|,nWrBU 14D«bsm lrrljiUou Project Hydrogeological Investigations AET = Pa|09 * ipVL)*'] Where p = grwsuai mean preCip^lation in mm - 1452.9mm ■>J 3007 1 - annual mean air Wftiperalur# in C n 3 20 L 3 300 * 25T + 0 06T* |mm] = tiOOrrim Hence, far (Jedcssa nver calGHmtni.. AET - 94d.57mm Therefore. n DrtEf n esLimale groundwaHT recnarge for DOClessa R^r catChmern, lhe vWue lAET = BM 57mm j ootarned by Tyre metnMl is uM* in the groundwater recharge eslmslon balance melhca dI Hence groundwater recnange m the Dedessa wer catchment oecomes as follows GWr ■ P - Sr * AET) = 1452.9mm - <944 57+ 210 S3j mm - 297.5mm This yafot is awui ZC 40% oi lhe total annual precipitation m lhe ana This mgn recnarge rare na> m attributed possibly 10 Lhe r 0a i frvBly Petter vegetation cover and tp the highly fractured r«r prevailing in the area F'-ally an average vafua from lhe two melhotis the tWM flow analysis method (196 6mm) and the waler oalance method (2&7 5mm). wmeh is 2*7,05 mm, has to Oe used as annual, flKMfowatar Hcrerga o( 1he area This value IB about 17% at the qocai annual precipitation •n me areairjt Dtdcua IrngaUon Prcjoa Hydrogeological investigations 4 WATER QUALITY 4.1 Water samples teiurai wier mtrtds wtih env.cormeni, an also rt -5 affected by ant^pogemc process M*T W fl changing <ts chem»cai. physical and Biological constituents The utilization o reawres an understanding of such constituents. Hence, the water should mee quaMy sianaard that «5 set ma«n>y cased on its purpose iff order IO use t Some po _ physical anc chemical parameters have teen determined for the water ol the study compare its quality with certain standards set by different Organization such as WHO specific A-aler uses Water samples rrom drffereni sources nave oeen taken for physicochemical and microDKMogoi analysis oased on the actuabexisting geology hydrogeology and geomgroAoiogy of the area Accordingly, a total oi thirteen samples have Deen taken Irom springs anc Wells Fig 4 1 snows the location of the water sample points All the samples haw* seen suomiiceo io the laboratory or WWDSE ror analysis In addition to these water s^mpes collected during the field work, previously analyzed water quality Dy drffereni institutions nave seen jsed for nydrogeologicai interpretation of the area. Among the collected water samples, four samples were taken from springs and nrne were from oorenoies The numbers of samples have Been oetermineo based on various conditions such as geoiog^cai and hydrogeological setup of the area and availability of previously analyzed pnysico-chemfccai and* mHcrobioiogical data in the area Water Worts Desifiu & Supervision Enterprise In AssocLntini with ItlerenntUKjntxl CodsuIuluu ud Technocrat* Pvt Ltd 16<1A 40 (towing witsr wmpie points in Arjo- DtdfUi project «r*« _ 0 40 faorttmffArjo Btdsjsa lrriE>tiOB Project Hydrogeological Investigations 2007 4 2 Sampling techfiiqucs and analyst One duplies a total of thirteen samples have b«n ofled laboratory result? sampte » collected from spring m order <0 see lhe reproduobHrty of lhe _ ar^iucM nn ii In order Ko undertake Naiurai waler is sampled ift view of carrying out various y . - h»wn nollected for physicochemica. analysis me an^iwsifi The waler quality analysis water sampttS- have been co covert water samples were from ground water <E(W and Well.) sources The samples nave peen taken with one lifer capacity plastic Dollies Irt order to compare phySiMcnemiqal parameters, some physical parameters such as TDS Solids, Temperature and PH nave been measured at fiard m order to compare with mat nt Laboratory 4,3 Pictorial repftsentalions of water quality analysis 4,3 1 Piper diagram The Piper diagram plots the major ions as percentages of milh-equivahenls m two base triangles The Piper irilinear diagram far water samples m Arjo- Dedesaa is available at Fig 4.2 Tne total cations and Lhe total anions are set equal to 100% and th* data points m the hwj mangles are profeci^d onto an adjacent grid This plot reveals useful properties and relationship? for targe sample groups The main purpose of the Piper diagram is to show clustering oi data points lo indicate samples that have similar compositions Dissolved the result Tne P^per diagram can be used to plot all samples in the open database or selectea sample groups m addition, the symbols representing lhe sample values can De Customised according Id shape and color Other options include individual multiplication factors for each selecctd ion 10 prevenl data point accumulation along a case line The highlighted sample points indicate samples that are selected in th# database ano are also highlighted on all other open graprnical displays According to the water samples ptotted in Piper Irilinear dag,ar, to, A,».0eo.saa area. samples dan fie calegonzea baaed on (hei, claslenng aa Ad-01 iO-'O AD.12 ano M>« as one category AD 02. AD-03, AD-04 AD-OS AD-OS ano A0-11 as saeana ca^on,. AD-07 ana AD-OS aa u™a ca.egar, and f.na»y AD-OS aa fcWto c.l.gcy rtowwr. d « reline (unbar the waler type baaed aa ,he cbem.de! composition, (hey can be categ&ri^Bd in to five categories Wator Works Design iSuperrlsion Enterprise 1. ™ ...a™^ C M1UDU „a . 18Arjo-Deftssa IrrtgiUsn Project Hydrogeological investigations ■ Na- NCOS w.isam(« AD.01 ■ AC-07. AO-OO *0-10. AD-,2 AAd AO-.3) • Ca-rtCO3 type (Samples AD-02 end AD-111 Miy aw? • ■ • Ca- Mg- HCO3 lypc (AD-03 AD- 06 and AD- O9j Ca- Mg- Na- HCO3 type i Sample AD ■ 04 J Ca - Na- HCO3 type ]Sampl eA D-06? Th, ,□ aruor. ™ «.he d.He-.h. aa.np.os ^ea..ng «r»ua eonmuona o' rucn-water interection. 4 3 2 Schoe-ller diagrams These seoii-iDgaritlunit diagrams were developed io represent major ion analyses in meq baa kj aemonstrate different hydrocnemicai water types on me same diagram. es typ graphical representation nas the advantage that unlike the trihnear diagrams, actual sampe concentrations are displayed and compared The Scnoelter diagram in AquaChem can be used >c p»i all samples in the open database o* selected sample groups only Up to 10 different caramelers can ce included along the K-axts and the symbols representing the samnie points can oe customized according to snape and color The Highlighted lines ir-dcate specific samples that are selected m the database and ere also highlighted on all other open graphical displays The Schoeller diagram for the water samples of Ago Deocssa area is available n Fig 4^3. Water of similar source (type! shows a similarly snaptc curve where as water of different types snow differently shaped curves Accordmgty two major types erf water can oe .oentified from the graph Calcium Drcarbonate Lypes Samo*es AD-02. AD- 03. AO- 04. AD- OS AD- 06 AD- 09 and AD- 11) ana the sodium bicarbonate types ■;Samples AD- 01 AD- 07, Ad- 08, AD- 10, AD- 11 ana AD- 13) 4.3 3 Stiff diagram The Stiff diagram method of water quality representation jses a scale (or concentration of JO n& in along me r3l« The tons are arranges along y-axis in such a way mat Ite aeons Na' Ca*“. are w the iett of the cemw □! m ^tnng scale ana me amans are e 10 lhe right Dl 11 It rs snown Im some the analyze samples .n F»g 4 4 Acoonj.pg [D this ngure water S.mpfe of the project r can oe calegonzed m io ;hwe majOf groLjps Na. 9 SB HCO3 type .samples AD-Ol ADO?. AD-08 AD-10, AO,12 and AD-13), Ca-HCO3 type * a"pwS AD-02. AD-03, AD-09 and AD-11>. and Ca-Na-HCO3 type (samples AD-D4. AD- 05 and AD-06). Watw Work, ntsijtn 4 supervision E^rprise---------------'------ - In V.U, C „„||1OU <M r^M“ B 19*4 » SO4 •0 0 AW’ H AtM# ♦ ATM3J - AiXM X AD-CS * .4^ ■0 ac-;‘ A mmm V ACWB >- AD-14? X * A£>M ACtiJ AD-TJ 'K' Ftg. 4-2 A map showing Piper trifinear diagram for water samples in Arjo- Deaessa areairwpf] ACMJi a :±z AD-02 —< ... AC-03 _ „ - s AC-I> -■■A — AC-Ofi A£j-O6 AD<F aDZ# -3- AC-09 -■- A&10 0 AD-11 A0-12 * S' Ca Cl SO* NCQ3 fig. 4-3 A map showing SchoeHer diagram far wafer Mmptas in Ago-Dedessa areaC- - it — »c ■ at?- c: ci rtcca so- CQ3 i I I I I I I I 1 I I 0 c: r>CC3 50- C!3 w &• Mf d =- ■> hQO3 1 LX SO* _L EC3 Kl Ci Mg K i1 I- 1 Cl hCC3 SO- COS 3 3 * *A>OS’ * V fc nup sh*mfi San diagram wr watt, »mpirt in Arjo- TteaesM Prtyta ar«a rOonceriL maq?_j 1_ ill K A CJ HC3J 50- COS AD- P9 «1 3 AD- 11 * c; ■fc Si *a K 1f X ** HCQ3 SO4 CO3 <■ «K13 I *Aflfrhdtni ]rri[id&D JTpJ wt Hydrogeological knvestigatLom 4.4 AgriC'dlEurai/krigaiicrt wafer quality . AgncuttlMi EuiLaoihly of wafer depenas cn flop type. ClnmalB. M>il typ®. <ind l, TI<!u"i fflflaban waLer use ■Dbvij 196Sj The mam pawrteW* Io be analyzed tD *vP'uaie imgabort wafer quality ate Boran Sodium hazard. ang Sal mil j These parameters a e pienU e^her di.-^dly (B.g by causing an aduerse pfiySKlfookSl effects ) or indirectly (BQ by Tiling pian[ j.M[ ftetntflt Or mpislure uptake) Sahndy is best eslrrnjled based OO ElacLnua Co.idudiYily [EC} value OttWf Jirecl indicator □* salinity is Tolal Dissolves Sohns (TDSy Th* iwc parameten TOS 4 EC are twisted by the Following M nation TDS imgfL|= E40 k EC fdSfm) wtiar* m^L = milligram per hire. dS?m - deci Siemens per FMfer Accc.'dmg to u S Daparlmenl of Aflflqrilure, waler witl an EC greater than 4dS/m ft considered as salrne Sodium ihasardi >5 dsfr&s&eti Dy 1he s&>callecl Sodium Adsorption Ratio (SAR?. 11 «s caused by sotfc water Sodic water is water Uhat mas high sodium canraniration relative to the cDFizenLraliofi o1 caicjum and magnesium Water is said la oe sadic if rts SAR is greater than 12 SAR is calculated as foltows SAR= tM*T^5[C» * * Mg**| a 1 Where Lht concentration of each calton is expressed in imt-q/L If the concentration is expressed m mmoi/litrt SAR = (Na‘p >' [Ca** + Mg ’] According to Todd (IMQ and reference? there in), the water quality evaluation for irrigation baseo gfl SAR an<j EC are shown in Table 4 i Ta&ifr 4.1 SAR and EC valuer in terms nr irrigation waler sutedility Ww :im fjMiir-H Gootj Fair < id Poor 5-hP i0- i& ’8-35 WJlrCW Easafttere EC «.]S IT ■ -iln ■■25u 250- T5Q P-WmtiLfU>oi Doucil lb KMK 2000-M0Q u™ Jirabe -3000 „ Mtr B ™i. »,l.r , uailty (w lmga,iwi (rom 3,,^ anfl Sod|(]m W *, ltD.d.5S. we Mr.™.,,, Men mwula() sno^fi in Table 4-2. i. lister Works DesigniSupervision Enterprise — CtD!Llunii iM T[ £«' a 3**Fjd DEdnu Imf >uon Piajin jy«ln)gBpn»gieaf iiiYisnganons iBDlc i.2 SAR and £C values(cx swrtace and grounff-^aier in 3007 a area n.1 lx ■Q-J at a ” *£ •■ r—-1 11^ , 21 £ L__ 3JM Acci-cnq k 5AR values owned IflT the MB»f »"'(*«■ AD-Ol . AD-07, AD 10. AD AC-13 M all «#c -to. >« AD-OS.......................... .. “A”'' m a,a al. non MO.O f-vr imganor ooisr flUPMy t*"* »' «*» IM’ ,3"9a ' ° excellent quality “□ poor ctuaiity Buifromwlinifr pint Of the qurty «r«4 frtm ”• 'ne ,e,T!ainin9 " fm id unsuitable. i.e from 41B Ii5.cn-.1o4450^cm ftothef worts itMbtsaid fte salinity ranges from medium sahnny 1C vtry Hh^i saliruiy F<g i 5 snows values of TDS and EC far cftfcriwl walat samples ft the ptoteci area Fifing 4“5 Etecsncai condueimty (EC) <n us/cm ano Total Dissolved Solods (TDS) in mg/L lo< *aiar samples in A^o-Deoesse area ™ g.aon ca.ly mdKa.E, TO eTOn. o> SMnlly lor „ ate, a. in, TO EC and TO TOS Contour map a TO TDS .. a.a.TO.e al F,o 4 6 the „0]ic- '« MKnp„w M me “““ on to., Eiednc ^WM, „ TDS .„ -, MIag0IIZBa lmj fr ' ., us lo ABSGtLul« wm InrsttoBClnMol ........ ............. Water Works Oosigu 4 Supervision Enternrlsf ' a IflnjBitua M(1 TtclflQtrita • ,ns e 24Arjo Dedessa tmjatlnc PtoJbcI Hydrogeological Lnvesttgadons bUf 20(17 AD-OS AD-Q4. aD-05 and AD 06) nave low »i*»rty. four samptes <*0 07■ and AD-13 have h^h salinity . and two samples (AD-01 and AD-10) are extreme y ? Th,s qu3lltallve desertion doesn't lolfow standard procedure of water qu y classil.cation based on TDS and/or EC. but H * s^ply for the sake ot descnption sampes cooed as AD-01. AD-10, AD-12 and AD-13 are all from springs, all other waler samp^s are Irom bomholes (drilled shallow Wells) Hence, it is possible to conclude evan if they are all from groundwaler, they art from different aauilers The more sail water high TDS values! are mainly from weathered casement rocks (granite granitic ^egmalde.i, and oeep-seaieC volcanic aquifers especially along fau I Ihermai springs). ,9 1 Water Works Design t Supervision Enterprise In ASMcUUM with lotencnilooat*] CoanKuu ud Techaocraxs Pn. Lid. 25□□2 ftg 44 4 mip stow/ng IM contour tor Totof DiMofred 4i>o - Detfesu Pro/rcf ar** sobd* fros/ns^ *>' 4t M A imp sftors* contour tot Total Dni&Mrf SoMtfJ fTOS ‘ Arjo - Dedeiu Prttf«r <f*»*rjn Qi'Otss* irrigation Project Hydrogeological investigations 5. PIEZOMETERS OBSERVATION WELLS AND WELL FILED 51 Distribution of Piezometers/Observation Wells In order to monitor groundwaler qufllily and quantity o! the afC3 bu1Tl bef°ra‘ a constructicu", ot the oam under investigation, a total o1 f ourteen ppez&meiers Obse wells hire been proposed and their sites have been located. The geograph config.jrabQn.'disirit>ution of the piezometersrObservation wells is selected base gecH&gy nytvogeotagy. topography grwjntfwater flow direction, etc of the area Since the deplf c! the ptezometers io be construcied rarely exceeds 100 rneters, PVC casing rerem mendable tn soma cases the exSting well oeolh al the immed.ate down stream o' the proposed flam axis are 50 - 70 melers depth Title 5 1 ihow$ <he geographical coordinates or the proposed piezometers Tacie 5.1 Locations nt the Proposed Piezometers Jiij 2007 u*Dgrrphic*l eoerd knatf E (UTM] I 3*r Ko Pitigmirtir codti Eitting Marthmg AIMudW |m} .. .............1 1 p^l 2*1243 945073 1332 2 P-er2 23957B 942443 134B 3 P-orl 235229 948568 1354 * R*E.“4 232364 9*5622 1345 5 P.p-i 237407 Ml 746 1391 6 P«-6 22MS2 944575 1374 7 p «r? 230 IM 952670 13B6 6 P-n-B 225779 947133 1324 9 f\B-S 220 ns ■»——------------ 954111 1341 10 P-4S-W 21767? 951707 1319 11 317135 M1437 1332 i 12 P-^12 21271* 95244* 1354 13 Par-il 2l«S4 ■ 95508? 1323 21333# Lu 961320 1320 T he consLfuction o4 ihese piezometers shall iolfco w the standard procedures although some s.te-specihc cdOdiHons such as hydrogeology) Mi up will a.so matter Tho , QCal1o n ' o1 th8 ’ proposed Piezometers >s available &n the map srm^n ,n Fig 5-> Water Works Design k Supervision &ternnsl ----------- --------- 27Aijq D’Edem LrrlgjlUcib pjojecK Hydngeclogical investigations 5 -2 Future well field May 2*£T7 The Poteniiai aqurier$ for groundwater storage in the area are basaltic lava flows with minor sai'Ci including rhyoliie and ignimbnte. ano alluvial deposits in the river valley of Dedessa Thi$ can tie verified by existing boreholes data in the area For example, Borehole data m Agarc area snow this situation. Well field sites on which detail geopnysioal investigation shall be undertaken have been ideniiliec nasea on geotogtcaL hydrogeological and geomorphologicai seltmg/or approaches Tesi wells drilling and construction shall follow the detail geophysical invesiigaUon Waterworks Design & Supervision Enterprise In R-sshIiUoh with teuwiMttMMai Cvumtluia Mi Twhentcrats Pn Lul5-1 a nrap snowfng proposed ^Momettrs, water pomes arxf waf*r sampling pomts L —_ ’VCW u#r**> ■h?u Si£>u Str* >uzo AW |9orr#y4 Goto Sex* CfleiArjo BfOrssa Irnftidca Frnject Hydrogeological investigations 6. WATER LOGGING AND DRAINAGE 6 1 Topographic features and soil characteristics The jnauiasing and rolling topography »n upper pari o1 the project area g a > gentle nope pl flat land m Hie txXIom valley of Deflessa. especially [he icwe pa . cormnand area necomtJ almost flat This Hat land is covered wifi sediments a y callu. .il aelluvial and alluvial angin This sediment is underlain mainly Dy Las The topography and iand chaiacrenSUGS af 1he command area can t>e sa>d ■ o level > 1%). nearly level (1- 2% slope,1. very gentle (2- 4% slope , and gentle (4 6 slope categories as about 35% ot Ife command area (alls under firsl two categories and about 23% o1 the command area falls under lhe last two categories Though the command area IS sttin, d rtas a rolling topography ano there are several small hills dispersed m the coiTimarifl There are nftng hills also an the outer boundaries of the command area on Dot bank? ol river Dedessa li*y 3XT 1 maior part of lhe area is comprised of vertisol (47% ol lhe command area) thal has vfrry low LW^n^aciility Nex: w vertisots arc cambisois ano luvtsols covering 15% ana B 60% of the are m respectively Hence this sb«l type hinders lhe in fibration of lhe most incoming racial during rainy season On one hand thia neips lo restrain the rise erf (he groundwater table through reducrig infibration. on the othe< hand lhe plain nature of the land wouldn't aito* t"<& surface run off to How out easily 6 2 Existing groundwater table Grou-Ml water teval m lhe projeci area varies from 2 lo 20m h g I In lhe command area the groundwater taoifi is 2 meters baiow surface during rainy season except in few exceptional cases ,J surface water logging During dry season lhe groundwater table was 1ound deeper lhar 5 raters below natural ground surface The nse of the groundwater table can happen oue JiHereni rwtoral condilans anq man made activities. The appl,cation of irngaicn praence is toe maior human mterfereftces foe nse of groundwater table Th® method of xngaton (orip furrow ete) that is practiced and the crops proposed to be grown *,li deiemwva the extent to which if may affect lhe nse m groundwaler level of tr>e aoa Water Works Design t Supervision Enierartse---------------- “ kmctali. |Bi™oUbmw hl u< imArjo DedesSa tm£itfo6 PTuJ-ctc Bytlrogtologtcal investigation 6.3 Future groundwater table and recharge frorrt irrlgsrilon Whenever mere is a mapr mgatpri project wilti continued BrHJ intensive irng there IS always an apprehens.on of n$e of groundwater table * nse of ihe groundwa e labie is significant, and n continues unabated, it may cause serious adverse p lertiicy or (h® land Some of the -adors that aflect the nse of groundwater are ■ Topographic features * Lane cftaraaenul« * Naturae drainage system * intensity and amount of rainfall * ExisUng grounawater taole * Son characteristics * Crops ana «ls water requirement * Seepage and other losses from cana< system * Surface drainage system implemented ano its effectiveness MV 2OC7 f T*» esiimaiM annual crop waier requirement al pnmary canai neao. for venous crops Io be cuflwBlrt m the command area of lhe pnjposea Arjo- Deoessa project composes lour set of vaurt-s categonaed under two phases each phase having two rotations. This rias been snowh in Taoie 6 1 Tania 6 1 Annual gross crop water requirartwrrt » primary canal head Str ho Phase Rotation GCWR (mm) 1 1 -J 1 987 40 2 1 ' 3 __ i II 1 1086 14 bl 1 1311 47 4 II II 1423.234 - In order to assess groundwater recharge from imgalwi water the maximum value of lhe Gross Crop Wwef Requirement l.GCWR? in the s*conn p base o f $ «ond rotaLon that 1423 234 ™vyr has been used Therefore, the groundwater recharge from the appl.cal.on or irngatoOH nas been eslimalec under two main situations as follows Water Works Design t Supervision Eritmrtse--------------- — In ^scctttioa wim liLttxoclineat*) CoBsuluata nd Tech noerxe LldDedeisilmgidcn Project M>y 2OT7 Hydrogeological investigations . ihni rjSTifjrt fiul Cjf ttlU' l‘Dl-tl'1 1 According to groundwater recharge estimation made • annual precipitation in the area, only 1T% is gcwng fo* recharging the grou if Ihe same scenario is corwdaracJ. annual ground water recharge application or irngaleon in the command area becomes 241 95 mm. T crude estimation since various factors among which the irrigation method can affects the groundwater recnarge 2 Along with other crops cultivation o( paddy rias bMH proposed in the command area Paddy is the only crop mat requires constant standing water in the field for rts growth and d evelopmenl. Thus paddy cultivation results into percolation loss, and only that quantrty of water which fS lost through percolation has lhe cihancu and tendency of reaching groundwater H may be noted that about 330 mm of water is eslimaifrd to de ins! through percolation, and onty this quantity of water has tne scope of reaching groundwater which may add to the rise of the ground water The intensity of paddy is only 30% in phase- K which will increase finally XO 45% m pnase- ii. Consfcdcnng the entire command on average, the annual contributions Qi imgauon wsner tc She groundwater would be 99mm in the Phase- I, which will increase to 140 5 mm under phase- II. Regarding other crops, they are all qty irrigated i e.. no standing water 15 required The imgauon waler applied to the field in case of all other crops except paatfy will be contained as sol moisture- within the rooi zone. Very smalt amount 01 water which will be lost below the root zone, will reach the ground water Other losses will be in form of surface runoff wnicn will pe lanen care Dy sunace oramage system As HUCh (he afldihDn IO grQu(ldwa1er 3 ue to imgation of all other crops except patty may be considered negligible and fherelcre. may oe neglected Seepage ma » the graunawara, I™ the Mna5 (mair, secOTd3ry cans!J, TOs also peen aalrmalu According ro unmo Slates Bureau ot Reclamation tU S6R r. seepage IM, Iron, anlinad lmgstlDrl ci na.r.a area tor «„ an0 ,oa„ !oite. Basm Qn ,s, 5 tan Ago- Dertessa rmgar.orr canal rs shown In Tattle 6.2 ano 6 3 8 32trTl(*dflU PrtjtCt aydrogeologicaJ iLTtsUpdons___________ _ _—- Tjbla 6.1 Estimation of wetted area for Arjo- DaOostJ irrigation canal ^OD? ■ Snr to Cmai tit* gory Av trig* witttd p*rrm*i*r Tout length M Art> (m ) 1 1 .ft _ Rtahl — —I Left Ltlt IN^I«1 . ----------------------- 1 Rignt ■ -------- ------ ——1 1 Warn CrBnai 2 ■zaniii 3 Tertiary utill Totai a 7iis Mill 42.800 00 . eojflO 00 1 ”279 639 00 . "*60 873 00 131,896 05 2 795 2 795 49.370 00 47'9D 00 137 989 00 1 02 1.02 199,4M 00 Z39 100.00 203.453 00 Total Am* [m’f 7*0.312-00 269*85 05 ----- — f--------- 3— 1------ ""--------- ”1 243.882 30 *47.33 5.. 00 11_*4■737r 317• OS & 621,061 00 836.651 05 U nt w ™ W*' irx “> ™>* Table 6 5 Seepage iwb from jnllned Arjo- Pedessa Irrigation canal Nt? Cwnmarfl area l*nng] Riqni Bank Wetted area 0« Csnai (mi1) M»n canal Seconoa^ canal Tertiary oana< Total wetted area (m ) 3 Total seepage loss (mmj ? LHttBawr ■3 Tout rT Tfful Swp»4" t<nTl 279.639 00 137 959 00 203 *53 00 460 873 00 131,896.05 243,882 00 7*0 512 00 23,320.796,31 2M MS.D5- 447.335.00 10,605,35*73 621.081 00 036.651 05 1 *57,732.05 *0.330^60 3P Zzut In (he seepage Isis MHmlation 1ram the Main canal, Wly 75%. of (ha tOlai area has tlMr considered TTifi duratran ol LTie seepage toss 13 cornered io tie eight months {October - htayl ano twenty F&jr hours a day for the mam canal, where as for six ninths 01 twenty four hours for secondary and tertiary tana, The oommanq area an which the seepage loss has Man averaged duI is the gross commanD area, i.e 17,625 hemares (T7fJ 25G 000 m ’) t the total seepage tass uf *0,33(1,350.60 m1 is spread io the grass command area rthich ge^e an average seepage loss of2Z6.36mm irom the wngai^n cangi Wusr Works Dts & Super? 151 on Enterprls e - ------------ 3J tn -tth IslarenntUrno J Ctrasmnta u a Tec Ji Pn Ltd.AJjO Dtdissi InitHgn Pjojmi Hydrogepfogical inrestlgatlDiis Therefore. the Laiai annual g<Du nd'^ier recharge bom the application d imgatio me SUm of« s.epag. loss f,«n th. «™!. W 26 and both th. pa.Oy .m9®«l (1 40 5 mm) ihat is 374.76 mmP Aflhaujn aeiaii aourfer and- soil sampling and analysis is required io come up result of the p&r&stty. ils value has been estimated to b« 35% -nine command area > considering a range from cLay to sand soils This parameter will &e used to graondwaier leyei nse due co the application of irrigation. Finally by knowing ttw grounowafer reenact from the appticaUofi of imgatiWk and the pwwty Cl the anuiler and the SOlI maienals 3M>ve it. the extant ol IOe groundwater nse du» to uh* aopticainjci d! rriQBilan has seen esiimateti under different scenarios as follows: Scunano I: No grnundw»t»r ftow* out of the calcnment (stagnant condition) Annual groundwater recharge from SpplicatKrfi of irrigation, GR = 241.95mm Effectwe paroiity of aquifer <sand] in commanS area. - 0 35 <35%. Grcundwaler level rise due 1Q application of imgaticn, GlNLr = GRrn, =241 95mm?Q.3S = 0.691 m. May 2007 Howevr- H anquio be noteo fhal grrxinrlwacEr is arways in a dynamic condition, nence. the siagnam groundwater condilton never prevails in lhe area Therefore, the Stated value of gpourmwater fevei nse (0 will never nappen Scenario Hr Groundwater flows cnjlof the catcfimem ^ynjmiC system) Annuel gmunawarer 'echarge rrqm application of imgalion GR = 24i 95mm Effective porosity o! aquifer;sandl in tOTimana aw, rk, = 0 35 (35%} Awarding Io M« flow separation methoa. the ratio Ol grounpwarer outflow from the ent.fe n.e< ratcnmeot to the groundwater lecheigt of the talchmenl from preciprtatLon is 79 53% nance, lhe remaining 20 42% of in* gibunqwater recharge contribute. to gr0unaw3[oMevB. n«. Simtoflr » »e apply W dynarmorty to ihe gr^n^ier recharge from .mgahon wrter ■ppfcMW. lhe groundwaier purii™ from lhe imgabon ppi, a calK>f> 1 92 mm i»amou.. Water Wark? Desk^n i Supervision EnterurtiT^ — igi 1-4ArjB De4*m Lmt*uon Project Mar Hydrogeological Investigations _ „ application cl irngahtm rn [tl Hence it we reduce this amount Irwn the recharge ■' u ( TOrmxwo above (!4>9Smm». ins ™i r«C«'9® •"*> oonlnbules to 9rou ™ a.™ only .S 4mm Thofstore. U«e. <h. ,«n«« <« 9™"°“'"..-! o- due .. IhedMl-WWnor.-ng^rtM GfOuno*ater i evel r ise Owe to applicator* ol «mgatior o 0.141m <-V4L, . GR<n. = 4 9 4 mm/O 35 Scenario III According io lhe paddy culbvation 3no seepage loss irom canals, ,h® annua ground*™, recharge from the apphcabon ol .rngabon * 374 76 mm as mentioned before ir |hi$ ts ihe case, me groundwBier level rise due to the application of irngalio stagnant groundwater condition becomes Groundwaier level nW oue to appltoabon of irngabon. GWLr = GR/ri, =374 74 mntfC 35 - lQ70T4nwn* l.OTm Scenario IV < Scenario III unoer dynamic condition): This Scenario assumes that groundwater ls coiMinijousiy I towing out of the catchment Hence only 20 42% (76 53 mm I of the groundwater recnarge from irrigation water w4l contribute to Ifre groundwater level nse There1cx«. the groundwater level nse under this Scenario becomes. GWLr =■ GRyn = v 76 S3 rnrttfO 35 - 218.66mm = 0-2l9m In conclusion. the assumption of stagnant groundwater condition Scenarios (scenario I ano IIIH over esbmaies me groundwater level rise due lo th* application of irrigation Because it assjntes- stati&or stagnant groundwater condrton that ts not the case in reality since grounawaier is usually in a dynamic condition The second Scenario (Scenario II) relies on ground water recharge estimator! from irrigation water application equals that 1rom preopitatort However grourttwaw recharge from irrigation waler application, particularly from paooy imgaiion and canal toss should be higher than from precipitation Hence, this scenano underestimates the ground water recharge Therefore, according to this ,n vocation. the Scenarw ihai works Ms' is Scenario IV Hence, the annual groundwater mb-vcI nse due to the application of irrigation water will oe 0.219 m Hoover " has to be noted ma' the tk.sMg soil in lhe command area lS mainly clay and .oam as from s*l survey isampUng a« analyst un(3er lhe Sam& Water Works Design & Supervisor! EnternrtsT’ ---------------- |b UMUln With iBt™u.ea[iJ CaunJUDis Md tX^u K ua 35 tIJloDeiisilrrHiDin Pruett jbdrogEQlagtti] inTesUgatiOQs M»y 2007 The soil has an average hydraulic condudrvdy of 0 CO00056 i .# C 402 mrd&y MJue s very small chibrting lhe miration of any water (precipnaJion or irngationj to GwidwaiBr Hence, the coninbution of ground-water recharge from me app..catmr *Tgabor; should be less than the amount stated here Therefore the groundwater ■e,.ei ise one to ihe application oi ungation cannot exceed 0 219rrVyear Another factor tnat tan reduce the contribution d imgatcn application io groundwater tecnarge is tne presence c* number of creeps ihai are transversal to the trena oi me commano ta and Dedessa River Soma titrated water from the miganon application will cwne cut as regeneration through lhe crMks belore reaching the groundwaler table Profile across some creeks ano Oedessa over m the command area *5 available m Fig 6 1 la. b c, d afflt ej The wies aeog winch me "ruPJes nave been 1aken are also shown in the map Fig. 6.2 Wfi-ougr there fi r» we^ documemeo well completion data in Ibe corr-mand area, [he depth 1c grrwrdw.r.er in ihe area u oeiow 5 melers Curing dry seasons except in some creeks such as Chub area I,eastern part ot command area I where the water table is about 2 meters beraw groyne surlace Onty lew ooretiales ano iheir data exist if. Ute Dedessa River vatley d project area since d H inhabited manly ihrough resettlements cmy 2- 4 years ago hence. axi6lmc1ion pl wroix map depicting depth to grawawater is hardly posstble under SvC-i cala ItmiLanon wee vwy are enlvtiy constructed 1or emergency purposes — ■»’—J*ia a/rZLk9zz ■oj 9tt0 K6t*S 'ISO Vw>TofVjo J30H1M0. 953187 677 From Pm 6 omw haU M trr^t *OWFrqff! P« Him •**?•« *<• i« pob Fiftsji.m, rfAi&trtvrs Aafcjkfii**-iwTWMilFJ0. fl? A mip fihowfnp Ira fJs* com/rtfliratfAljD-DsfltMi IrngiUim Project Hydrogeological inif estimations 7 SALINITY AND SODIOTY St IT ^°7 Salinity at soilsfwaier can be defined ki terms ofelectrical conductivity Paflicu 3 y rt is the electrical conductivity of the saturation extract However. sod icily >5 Ine^ of 6 xtTiangeaDle SQflium percentage Salinity may be C stegcrized ■ n to two b a&fid 0 sources primary {inherent! salinity and secondary salmty Primary (inheromj salinity IS denvaij bum the weafhermgi'tJegracJation cl primary rocxs/mi nera is It usually occurs when evaporation exceeds precipitation, Where as secondary wlkirty >s derived from the upward rnortmertl dI salts from saline groundwater through capillary size ihXler the situation of ir adequate leaching Thu situation happens mainly under shallow groundwater Mass flow Io the soil surface through capillary r» fl known to cease when the water table ta below 2 meLers m p oay and srlty nay; where as the seme value i& T 6 meters in coarse te flu red Waler ana so-i salinity occur aue Io differnm reasons. Among Inem are over irrigation that causes groundwater level nse due 10 in appropriate provision of drainage and/or crop water ■nefluiremertt calculaKm. poor method of irrigation, capillary ITM of grouhOwatbr due to natural!) nigh groundwater tavel below surface, etc When such raised grau newsier level is SuOtedtrS W ewpontion loss, the chemical constituents of the water will be left Over ana □eccmes concentrated on IhE surrare leading io soil and/or water salinity The leaching of some exiting nwlnenls m soit is also lhe potential source oi salinity ol water and soil m ttygation m order to MWH the possibility of salinity for the project area m the future. data haue dmr collected and have been ovjlualeo Among them are the existing groundwater quaky (physicochemical characteristics of groundwater}, ano soil chemistry Other Parameters that have been given emphasis here te the meteorological parameters that cause high evapotranspiration However, the high rate of pncWnuon (rainfall) m me ares an coufliarac the prat^m by leaching the hignly soiuWe saHS such as chlorides, au[pnares and arbowe sails Mrtdn 01 r.B1,«iy la)™ wato „ spoIad,c me srBa „ ,cr^s(aUinej M .no .a™ wn9s Cola gro„„ „ a a,er asSQc|aiM ivah ™"an< «-»« o.M « TOS, ana very |m M||nity A map $ Total DtaaolvM Solicre at tne brojsci Bn&a jB mailable at Fig 4 5 W>t« Works Design t. Supmiaon Enn^— — - 1.mmum «» H,ITO.U., BU1 cB1,to.u 39 wDedcsss IrrlgaUoB Project ^y^rogeoiogtcal investjgauons ________ Hence, !he roszorcj soiMwaiar salinity during ine des«gn penod o» toe project can be controlled naturally {through h»gh precipitation and topography of ine areaj or artificially througn appropriate irrigate water management. Water Works Design & Supervision Enterprise to AiMcktduft With ItttireoauaeDial Coasattinti mid Teebaocr*^ Pvt Led. 40LrrigfcUn n ProjKt Uydragagloglcalinve stigaiio ms 8. EXSITING AND FUTURE PROSPECT OF GROUNOWATER 8 1 Existing groundwater development Presently the- majority of the Woredas' caprisi lawn, and the rural community m the n^er catchment are supplied potable water from groundwater, eilher through bor&hole OTnstmcttOfi or from sprmg development with the exception of Bedels town that get water from Dating River Ihrougn lhe Treatment of raw water The yp&id of groundwater from some volcanic .ava tlcw shows very promising result bofn for cuirent and future water supply from groundwaler lor different purposes Can be mentioned &5 examples are boreholes for Aga re Lown wnare The yield ■£ about SOliUsec from a srngle borehole Furthermore, the aquifer in Ibis parbejiaf area has multilayer system attribulmg to a confinea aquifer Here, il is vital to discuss Aggro town as an example The town is entirely supplied water Srgm grouneweter through boreholes There are three new Boreholes and Two old boreno*es Among these Ouratrc*es, four boreholes are currently functional, one from the okl anb imee of the new borehoies m addition ip ihis. the Quaternary sediments in the nver valley are the potential aqurfers for groundwater development, particularly shallow grounowaler Other Wgreoa towns ih^t are supplied potable water from ground w-uur are Ajjg, Atnago Gaura ano Atnago 8.2 Future groufi£twaler prospect The sKisung gedog^BL meteOrofcogwai, hydrogeological and geomorphoiogicai conditions in ine fiver catchment indicate There are areas -Jhai can be aeveioped in tight of gfounowater lDTvariwS WMTftjpply purposes Acnnfotfy. potenuai well field sites hm been loentified in order to de^Etap ^ovntfwMtf Th™ MwiMtad well fie« sues hav« to be vnrifled based an g«pty»Cal mveshgalrann and Hit wM arifllLng bei<x& being wffiraty Pe^eloped The MaV aw* ***** limitation ,n the Klin groundwaier dMtaprrwH in lhe r U fla „ noL the quantity bul 1be quaUly Ire^ti^ly htfl Kon concenralion). Th» map of partial groundwater areas |D< luture d eve loom en! ts available t*l F«g. 8 1 tn Wiiftr Works Design t Supervision Enteric------------- -------- Tim tamKtalBU CMLiittMU U1 T«Hqflet<u Pvt L((19-T A map snowing GravnotaMsf potwi CM AW* for future ^avwtopmA/rt 0 SKOfl *****beservkd
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