Forrecentyears,runoffgenerationandhydrologicalprocessesinHailiutuRiverbasinhavebeengreatlychangedbyclimatechangeandhumanactivity,especiallywaterandsoilconservationconstruction.Inthisstudy,thetrendsinprecipitation,evapotranspiration(ET)andriverrunoffaswellastheeffectsofprecipitationchangeandhumanactivityonrunoffvariationhavebeenstudied.Theresultsshowedthatduring1960-2000,annualprecipitationandriverrunoff,monthlyprecipitationandETinSeptemberandOctoberaswellasmonthlyrunoffinallmonthsshowedasignificantdecrease.Inaddition,peakflowandbaseflowhadalargedecrease.Underthejointinfluenceofprecipitationchangeandhumanactivity,themeanannualrunoffdecreasedby35millionm3fromthebaselineperiod(1960-1985)tothechangeperiod(1986-2000),whichaccountedfor60.9%and39.1%ofthetotalrunoffdecrease,respectively.Precipitationchangeplayedaprimaryroleinthedecreaseofannualrunoffwhereashumanactivity,particularlywaterandsoilconservationconstruction,alsohadremarkableimpactsonrunoffvariation.
