WaterFootprint-Presentation-General

1AComprehensiveIntroductiontoWaterFootprints©2009ArjenY.HoekstraProfessorinWaterManagement–UniversityofTwente–theNetherlandsScientificDirector–WaterFootprintNetwork:Hoekstra,A.Y.andChapagain,A.K.(2008)Globalizationofwater:Sharingtheplanet’sfreshwaterresources,BlackwellPublishing,Oxford,UK,ISBN9781405163354.3Thewaterfootprintofproducts14Waterfootprintofaproduct►thevolumeoffreshwaterusedtoproducetheproduct,summedoverthevariousstepsoftheproductionchain.►whenandwherethewaterwasused:awaterfootprintincludesatemporalandspatialdimension.►typeofwateruse:green,blue,greywaterfootprint.Thewaterfootprintofaproduct(goodorservice)isthevolumeoffreshwaterusedtoproducetheproduct,summedoverthevariousstepsoftheproductionchain.‘Wateruse’ismeasuredintermsofwatervolumesconsumed(evaporated)and/orpolluted.Thewaterfootprintisageographicallyexplicitindicator,notonlyshowingvolumesofwateruseandpollution,butalsothelocationsandtimingofwateruse.Thetotalwaterfootprintofaproductbreaksdownintothreecomponents:theblue,greenandgraywaterfootprint.Thebluewaterfootprintisthevolumeoffreshwaterthatevaporatedfromtheglobalbluewaterresources(surfacewaterandgroundwater)toproducethegoodsandservicesconsumedbytheindividualorcommunity.Thegreenwaterfootprintisthevolumeofwaterevaporatedfromtheglobalgreenwaterresources(rainwaterstoredinthesoilassoilmoisture).Thegraywaterfootprintisthevolumeofpollutedwaterthatassociateswiththeproductionofallgoodsandservicesfortheindividualorcommunity.Thelatteriscalculatedasthevolumeofwaterthatisrequiredtodilutepollutantstosuchanextentthatthequalityofthewaterremainsaboveagreedwaterqualitystandards.5WaterfootprintofaproductGreenwaterfootprint►volumeofrainwaterevaporated.Bluewaterfootprint►volumeofsurfaceorgroundwaterevaporated.Greywaterfootprint►volumeofpollutedwater.6DirectwaterfootprintIndirectwaterfootprintGreenwaterfootprintGreenwaterfootprintBluewaterfootprintBluewaterfootprintGreywaterfootprintGreywaterfootprintWaterconsumptionWaterpollution[Hoekstra,2008]Non-consumptivewateruse(returnflow)WaterwithdrawalThetraditionalstatisticsonwateruseComponentsofawaterfootprintThewaterfootprintisanindicatorofwaterusethatlooksatbothdirectandindirectwateruseofaconsumerorproducer.Directwaterusereferstothewaterusebytheconsumerorproducerhimself.Indirectwaterusereferstothewateruseintheproductionchainofproductsboughtbytheconsumerorproducer.Source:Hoekstra,A.Y.(2008)Waterneutral:reducingandoffsettingtheimpactsofwaterfootprints,ValueofWaterResearchReportSeriesNo.28,UNESCO-IHE.7AssessingthewaterfootprintofcropandanimalproductsWaterfootprintofacrop„Cropwateruse(m3/ha)/Cropyield(ton/ha)Waterfootprintofananimal„Sumofwaterforfeed,drinkingandservicingWaterfootprintofacroporlivestockproduct„DistributethewaterfootprintoftherootproductoveritsderivedproductsThewaterfootprint(m3/ton)ofprimarycropscanbecalculatedasthecropwateruseatfieldlevel(m3/ha)dividedbythecropyield(ton/ha).Thecropwaterusedependsonthecropwaterrequirementontheonehandandtheactualsoilwateravailableontheotherhand.Whenaprimarycropisprocessedintoacropproduct(e.g.paddyriceprocessedintobrownrice),thewaterfootprintoftheprocessedproductiscalculatedbydividingthewaterfootprintoftheprimaryproductbytheso-calledproductfraction(i.e.theweightofcropproductintonobtainedpertonofprimarycrop).Ifaprimarycropisprocessedintotwodifferentproductsormore(forexamplesoybeanprocessedintosoybeanflourandsoybeanoil),weneedtodistributethewaterfootprintoftheprimarycroptoitsproducts.Wedothisproportionallytothevalueofthecropproducts.Thewaterfootprintofananimalreferstothetotalsumofwaterusedforfeed,drinkingandservicing.Thewaterfootprintofalivestockproductiscalculatedbasedonproductandvaluefractions,inasimilarwayasinthecaseofderivedcropproducts.8Cropwaterrequirement1.CalculatereferencecropevapotranspirationET0(mm/day)e.g.Penman-Monteithequation2.CalculatecropevapotranspirationEtc(mm/day)Etc=ET0×KcwhereKc=cropcoefficient3.CalculatecropwaterrequirementCWR(m3/ha)CWR=ΣEtc[accumulateovergrowingperiod]Thewaterrequiremen