EFFECTS OF WATERSHED MANAGEMENT ON THE REDUCTION OF SEDIMENT AND RUNOFF IN THE JIALING RIVER, CHINA

(整期优先)网络出版时间:2004-02-12
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TheThreeGorgesProjectisoneofthelargesthydro-projectsintheworldandhasdrawnmanydebatesinsideChinaandabroad.Themajorconcernisthatsedimentloadfromtheriverbasinmayeventuallyfailthefunctionsoftheprojectforfloodcontrolandpowergeneration.Toreducesedimentationinthereservoir,watershedmanagementhasbeenadopted.However,thereislimitedinformationregardingtheeffectivenessofvariouscontrolmeasuressuchasterracingandafforestationonawatershedscale.TheJialingRiver,amaintributaryoftheYangtzeRiver,contributesapproximately25%ofthetotalsedimentloadinthemainriverbutonlyrepresents8%ofthewholebasinarea.TherehavebeenvariouslandusepatternsandextensivehumanactivitiesforthousandsofyearsintheJialingRiverwatershed.BasedonanalysisofthemajorfactorsaffectingerosionintheJialingRiverwatershed,themainwatershedmanagementstrategies(afforestation,farmingandengineeringpractice)areillustrated,andtheireffectsonthereductionofsedimentandrunoffarestudiedindetail.Thesedimentbudgetofthewatershedshowsthat1/3ofthesedimentyieldistrappedbytheerosioncontrolmeasures(afforestationandfarming)ontheslope,1/3istrappedbythereservoirs,pondsanddamswithinthewatershed,andonlyabout1/3istransportedintotheYangtzeRiver,whichwillaffecttheThreeGorgesProject.