ASSESSMENT iOF iIRRIGATION iWATER iUTILIZATION iFOR iCHAHAR iASYAB iDISTRICT iOF iKABUL, iAFGHANISTAN

Abstract

This study has been conducted on assessment of irrigation water utilization for Chahar Asyab district, which is located in the downstream of Maidan river basin in Kabul province, Afghanistan. Water iresources iof ithe iChahar iAsyab, ia isemi-arid idistrict iof iKabul, iAfghanistan, iare iextremely iscarce iand ilimited. iIt iis ihighly iimperative ithat ithese iresources ibe iused imost icarefully ito iensure isustainable iagriculture idevelopment iand iproductivity. iThis, ineed ito iin iturn, irequires iknowledge iof iirrigation iwater irequirements i(IWR) iin ithe iclimatic izone(s) iof ithe iChahar iAsyab. iLack iof ithis iinformation ioften iresults iin ifarmers iover ior iunder iirrigating itheir ifields iwith ia iconsequent iloss iin iyields iand iproduction. iVarious iagencies iin ithe icountry iof idetermined iIWR ivalues ifor ithe idifferent ibasin; ihowever, ifor iChahar iAsyab idistrict ior iMaidan iriver ibasin, ithe iwater irequirements iof ivarious ipopular icrops ihave inot ibeen iestimated. An iirrigation imanagement imodel, isimulated ithe icomplicated ion-farm i"crop, isoil, iand iclimate" iphenomena, iwill ifacilitate ithe iestimation ifor icrop ievapotranspiration, iirrigation ischedule, iand iagricultural iwater irequirements iwith idifferent icropping ipatterns ifor iirrigation iplanning. Although ithe iCROPWAT imodel iis iused ito iestimate iirrigation iwater irequirements ifor imany icountries, iit iis inot iused ifor ithe iChahar iAsyab idistrict. iThe imeteorological idata ifrom ithe iKabul iairport istation iof iKabul iprovince iin iAfghanistan iwere icollected iand ianalyzed, ithen iinput iwas iprepared ifor ithe iCROPWAT iirrigation imanagement imodel ithat iwas ideveloped iby ithe iFood iAgricultural iOrganization i(FAO). i Based ion ithe iliterature ireview, iit iis ifound ithat iit iis ithe ifirst iattempt ito imodel iexisting iavailable imeteorological idata ifor iestimating ithe iwater irequirement ifor iirrigation ifor ithe imost icommonly igrown icrops i(winter iwheat, ispring iwheat, ibarley, imaize, ipotato, ionion, itomato, igrapes, iclover, iand ialfalfa) iand icomparing ithe iresults iwith ithe ifarmers' iirrigation ipractices. iThe iresults iof ithe iCROPWAT imodel ishow ithat ithe iannual ireference ievapotranspiration iand ieffective irainfall iin iChahar iAsyab idistrict i1430 imm, iand i273.5 imm, irespectively. iAlso, ithe iirrigation irequirement iestimated ito ibe i(406.7, i673.2, i669.5, i734.8, i111.5, i863.5, i929.7, i339.7, i571.3, iand i681.9) imm/year ifor iwinter iwheat, ispring iwheat, ibarley, imaize, ipotato, ionion, itomato, igrapes, iclover, iand ialfalfa, irespectively. iOn ithe iother ihand, iresults ifrom iCROPWAT imodel ishow ithat ithe itotal iannual iirrigation i irequirements ifor iactual iarea iof ithe icropping ipatterns iare i5983.2 imm i(27.15 iMCM/year), iand ithe ipeak iirrigation irequirements ioccurred iduring ithe imonths iof iJune, iJuly, iand iAugust iwhich iare iabout i1359, i1661, iand i1274 imm irespectively. Results iobtained ifrom iCROPWAT imodel ishow ithat ithe iannual iactual icrop iwater iuse i(ETc), igross iirrigation i(Gr. iIrr.), inet iirrigation i(Net iIrr.), iand iactual iirrigation irequirement i(A. iIrr. iReq.) iare i6922, i7722, i5405, iand i5872 imm, irespectively. iAlso, ithe imoist ideficit iat iharvest iv i| iP . iestimated ito ibe i458 imm itotally ifor iall icrops iat ia idifferent itime. iOn ithe iother ihand, ithe itotal iflow ifor iall icrops iis i78.5 il/s/ha. Based ion ithe iresults iof iirrigation iwater irequirements ifrom iCROPWAT imodel, iand iavailable iwater ifor iirrigation ifrom iobserved idischarge iin ithe ihydrological istation, iit iwas irevealed ithat i40.25 im3/sec iof iwater iwas imore iin ithe iChahar iAsyab idistrict iduring ithe iperiod i(2017-2018). iBut iaccording ito ithe iirrigation irequirement ifor iactual iarea iestimated i9.55 im3/sec, iwhen icompared iwith iirrigation iwater iavailable ifor i12 imonths, iit iwas iobserved ithat ithe ifirst i5 imonths i(January, iFebruary, iMarch, iApril, iand iMay), iand i3 imonths i(October, iNovember, iand iDecember) iend iof ithe iyear ireceived iexcess iwater, ibut i4 imonths i(June, iJuly, iAugust, iand iSeptember) iin ithe imiddle iof ithe iyear iwere iunder ideficient iwater icondition. The istudy ishows ithat ithe iirrigation imanagement imodel i(CROPWAT) ican ieffectively iand iefficiently iestimate ithe iirrigation iwater irequirements. iYet, iit istill ineeds ifurther istudy ito ifit ithe model to the complicated situation of cropping patterns, for upgrading the ability of irrigation management of irrigation association in Afghanistan.