Thispaperusesmonthlystreamflow,suspendedsedimentconcentration,andmeteorologicaldatato
examinetheimpactofhumanactivityandclimatechangeonstreamflow andsedimentloadinthe
PearlRiverbasinfromthe1950stothe2000s.Theinfluencesofclimatechangeandhumanactivities
on hydrologicalprocesseswerequantitativelyevaluatedusingtheMann–Kendallabruptchangetest
andpowerratingcurves.Theresultsshowedthat:(1)abruptchangesandturningpointsinstreamflow
occurredin1963,1983,and1991whichwerefoundtobeconsistentwithglobalENSOeventsand
volcaniceruptions.However,abruptchangesinsedimentloadshowedsignificant spatialdifferences
acrossthePearlRiverbasin.FortheXijiangRiver,anabruptchangeinsedimentloadoccurredin2002,
andafter2007thechangebecomessignificantatthe95%confidencelevel.AtBeijiangandDongjiang,
abruptchangesinsedimentloadoccurredin1998and1988,respectively.(2)Thetimeseriesof
sedimentloaddatawasdividedintofourperiodsaccordingtoabruptchanges.Thecontributionof
climatechangeandhumanactivitiesisdifferentinthedifferentrivers.FortheXijiangRiver,compared
withthe firstperiod,climatechangeandhumanactivitiescontributed83%and17%,respectively,tothe
increasingsedimentloadduringthesecondperiod.Inthethirdperiod,thevariationofsedimentload
followedadecreasingtrend.Thecontributionfromclimatechangeandhumanactivitiesalsochanged
to þ236%and 136%,respectively.Inthefourthperiod,climatechangeandhumanactivitiescon-
tributed 32%and þ132%,respectively.Meanwhile,FortheBeijiangRiver,climatechangeandhuman
activitiescontributed90%and10%inthesecondperiod,thecontributionofclimatechangeincreased
to þ115%andhumanactivitiesdecreasedto 15%inthethirdperiod.Inthefourthperiod,thevalue
forclimatechangedecreasedto þ36%andhumanactivitiesincreasedto þ64%.FortheDongjiang
River,thecontributionofhumanactivitieswasfrom74.5%to90%,andthevaluesforclimatechange
werefrom11%to25%.Therefore,theeffectofhumanactivityshowedbothspatialandtemporaldif-
ferences,anditseemslikelythatthedecreasedsedimentloadwillcontinuetobecontrolledmainlyby
humanactivitiesinthefuture.