Page 60 - 2023年第54卷第11期
P. 60

Studyonthespatial - temporalvariationsofrunoffand
                                        sedimentinthelowerreachofJinshaRiver

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                        XIEYiqin ,DENGAnjun ,DONGXianyong,QINLeilei,ZHANGBangwen               1,2
                            (1.StateKeyLaboratoryofSimulationandRegulationofWaterCycleinRiverBasin,ChinaInstituteof
                                       WaterResourcesandHydropowerResearch,Beijing100048,China;
                             2.KeyLaboratoryofSedimentScienceandNorthernRiverTraining,theMinistryofWaterResources,
                                 ChinaInstituteofWaterResourcesandHydropowerResearch,Beijing100048,China;
                                 3.ChinaThreeGorgesConstructionManagementCo.,Ltd,Chengdu610041,China)

                  Abstract:Thevariationsoftherunoffandsedimenthaveagreatimpactondepositionprocessandtheoptimaloper
                  ationofthelargecascadereservoirsinthelowerreachoftheJinshaRiver (LJR).Alongwiththeconstructionofthe
                  largecascadereservoirs ,thepatterns(space - time)ofrunoffandsedimenthavechangedsignificantlyintheLJR.
                  Basedontheobservedhydrologicaldataofmainstream andtributariesintheLJR overtheyears,thevariation
                  processoftherunoffandsedimentwereanalyzedandthepatternsoftherunoffandsedimentindifferentperiods
                  wereproposed.Intermsoftimeline ,theannualvariationsoftherunoffcomingfrom theJinshaRiverstem,the
                  maintributariesofYalongRiver ,LongchuanRiverandNiulanRiver,aswellastheothersmalltributarieswere
                  notremarkable ;whilethesedimentloadvariationtrendsoftheabove - mentionedthreesourcepartsweredeclined
                  significantly ,obviouslyandnotsoobviously,respectively.Intermsofdistribution,theproportionsoftherunoff
                  intheJinshaRiverstem ,thelargesttributariesYalongRiverandothertributarieschangedlittleindifferentperiods
                  around46%,45% and9%;whiletheproportionsofthesedimentloadintheseregionschangedsignificantlyin
                  differentperiods.Before1999 ,theproportionofthesedimentloadintheJinshaRiver,theYalongRiverandother
                  smalltributarieswere40%,36% and24%;afterErtanReservoirconstructed,whichlocatedinYalongRiver,
                  from1999to2010,theproportionschangedto61%,13% and26%,respectively;while,afterthecascaderes
                  ervoirsinthemiddlereachesoftheJinshaRiverconstructedfrom2013—2020,theproportionswere16%,31%
                  and53%,respectively.Furthermore,separatingtheunobservedareaasindependentregionasconcerning,there
                  werenosignificantchangesfortheincomingrunoffoftheLJRneitherindifferentperiodsofthelargereservoirscon
                  structedinthemainstreamanditstributaries ,norinthedistributionsofJinshaRiver,YalongRiver,othertribu
                  tariesandunobservedarea ,theproportionsofwhichwerearound40%,40%,9% and11%,respectively.On
                  thecontrary ,theincomingsedimentloaddistributionchangesremarkablyindifferentperiod.Beforethereservoirs
                  constructedin2013,theproportionsofthesedimentloadintheJinshaRiver,theYalongRiver,othertributaries
                  andtheunobservedareaswerearound21%,19%,12% and48%.Whileowingtothereservoirsedimentretention
                  ofmiddleJinshaRiver,97% ofthesedimentloadcomesfromthebothsidesoftheLJRcatchment,including82%
                  fromunobservedareasand15% from themaintributaries.Itshouldbedrawtheconclusionthat,currently,the
                  sedimentfromtheunobservedareasisthemainsourceofsedimentatpresentinthelowerreachofJinshaRiver.
                  Keywords:lowerreachofJinshaRiver(LJR);runoffandsedimentpatterns;unobservedareas;reservoirssedi
                  mentretention


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