分布式水文模型介绍 泥沙 dhsvm_sedimentppt课件.ppt

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1、DHSVMSedimentModuleModelOverviewExamplesRunningtheModelDHSVMWatershedSedimentModuleDHSVMMASSWASTINGSURFACEEROSIONCHANNELEROSIONWatershedSedimentModuleOUTPUTQQsedMassWastingModuleMASSWASTINGSoildepthDEMSoilinfoVegetationinfoP(cohesion,etc.)Multiplerealizationsoftotalfailurelo

2、cationsMultipletimeseriesofsedimentsupplyMassWastingModuleDynamicrelativesoilsaturationpredictedbyDHSVMNestedgridsforfineresolutionfailurecomputationSlopeinstabilityindicatedbythefactorofsafety(ratioofresistingforcestodrivingforces)Uncertaintyinfailurepredictionsisassumedtob

3、eprimarilyduetouncertaintyinthespatialvariabilityofsoilandvegetationcharacteristics.MWM-StochasticNatureFourvariablesareinputasprobabilitydistributions:soilcohesion,angleofinternalfriction,rootcohesion,andvegetationsurcharge.Thevariablescanbeassignedtooneoffourdistributions:

4、uniform,normal,triangularorlognormal.Theparameterdistributionsarerandomlysampledforeachof“MaximumIterations”timestodefinearangeofpotentialfailurescenarios.MWMMassRedistributionFailuredepthisequaltothecurrentpixelsoildepthFailedareacanincreaseinresponsetoaninitialfailureThela

5、ndslidestopsatanempiricallydeterminedrunoutdistance.Thefailedsedimentvolumeisevenlydistributedamongalldown-slopepixels.Landslidesenteringthechannelsystemmaycontinueasdebrisflowsdependingonthejunctionangle.SurfaceErosionModule-HillslopesMultipletimeseriesofsedimentsupplyOverl

6、andflowSURFACEEROSIONRoadsandstreamsSoilPrecipitationVegetationDEMDistributionofsedimentdeliverytochannels(roadsandstreams)HillslopeandroadsurfaceerosionmoduleRunatthehydrologymodelresolution.MapsofsurfacesedimenttypearesuppliedtotheSEMfromtheMWM.Runoffgenerationforeachmodel

7、pixel(“effectiveprecipitation”)isdeterminedfromDHSVM.Overlandflowismodeledusinganexplicitfinitedifferencesolutionofthediffusivewaveequation.Sedimentsupplyfortransportdeterminedby:Soilparticledetachmentfromraindropandleafdripimpact,andSoilparticledetachmentviaoverlandflow.Tot

8、alerosionislimitedbyoverlandflowtransportcapacity.SurfaceErosionModule-Chan