简介:在土壤外壳开发的降雨事件运动的影响经由实验室实验和基于物理的水文学反应模拟被调查。流量和土壤水内容数据被分析以便在许多降水条件下面学习不同外壳的开发时期。当一个稳定的状态,能被雨点影响的一个扩大时期打破,被发现为外壳并且,随后存在时,结果证明显著地改变的外壳的形成玷污浸透的水力的电导率(K)和流量流量特征。在K的减少为下游动人的事件象86%一样高,并且72%为在上游动人的事件,说明降雨运动的方向比降雨紧张和持续时间在外壳形成上有更重要的影响。同样下游动人的降雨事件可以比那些移动有更大的效果在上游,在雨点影响前的一个depositional外壳的发展可以在决定最后的K价值起一个重要作用。
简介:Onthebasisofpreviousresearchandpractice,anewmodelsandBZYhasbeensuccessfullydeveloped.Experimentshavebeencarriedoutonitsproperties,includingunitweight,initiationvelocity,settlingvelocity,reposeangle,etc.TheexperimentsshowthattheBZYmodelsandhasmanymeritsoverothers,suchasadjustableunitweight,widerangeofparticlesize,particleshapesimilartonaturalsandandstablephysicalandchemicalproperties.Thusithashighvalueforstudy,developmentandextensionforapplication.Stillsomeofitspropertiesneedtobefurtherstudied
简介:ThetheoreticalconditionsforthebenddevelopmentorattenuationhavebeenreviewedandtestedforastudyreachoftheMeghnariver.Thefieldobservationsinthenaturalalluvialmeanderdonotsupportthetheoriesdevelopedforbenddevelopment.Thelimitationsofthetheorytoapplyinthenaturalmeanderingriverarediscussed.
简介:Ahighlyefficientflowdischargemeasuringmethodwasproposedinthisstudy.EitherthetraditionalvelocimetersortheAcousticDopplerProfiler(ADP)canbeusedtomeasurethemaximumflowvelocity,Umaxatthey-axis(verticalpassingthroughthemaximumpointvelocityinachannelcrosssection).Themeanvelocityofthecrosssection(U)wascomputedbyφUmax,whereφwasestimatedfromthefielddatacollectedwiththecup-typecurrentmeterusingthe"two-pointmethod".Theflowdischargewasthencomputedbymultiplyingtheestimatedflowareawith(U).Incontrasttothetraditionalmethod,whereflowdepthandflowvelocitymeasurementsareneededforeachvertical,theproposedmethodhastheadvantagesofshortoperationtimeandhighaccuracy.Thesefeaturesareespeciallyimportantforthemeasurementofunsteadyflow.
简介:Thispaperhighlightspasteffortsindevelopingerosionprocessconceptsthatleadtothedevelopmentofthecurrentprocess-basederosionpredictionmodel,i.e.,WEPP.Recentprogressincludesthedevelopmentofamultiple-boxsystemthatcansimulatehillslopehydrologicconditions.Laboratoryproceduresenablethequantificationofnear-surfacehydrologiceffects,i.e.,artesianseepagevs.drainage,onthesoilerosionprocessandsedimentregime,flowhydraulics,andsedimenttransportanddepositionprocesses.Theserecentfindingsimprovesoilerosionscienceandprovidenewerosioncontrolstrategiesthatmayhaveadditionalenvironmentalbenefitsrelativetothetraditionalerosioncontrolpractices.Thepaperalsodiscussesthepotentialimpactsoftheerosionprocessonerosionmodeldevelopmentandfutureresearchdirectionsofsoilerosionprocessresearchandmodeldevelopment.
简介:Non-uniformsedimentdepositedinaconfined,steepmountainchannelcanalterthebedsurfacecomposition.Thisstudyevaluatesthecontributionofgeometricandresistanceparameterstobedstabilizationandthereductioninsedimenttransport.Flumeexperimentsweredoneundervarioushydraulicconditionswithnon-uniformbedmaterialandnosedimentsupplyfromupstream.Resultsindicatethatflumechannelsrespondinasequenceofcoarseningandwiththeformationofbedformroughnessfeaturessuchasrapids,cascades,andsteps.Abedformdevelopmentcoefficientisintroducedandisshowntoincrease(i.e.verticalsinuositydevelops)inresponsetoincreasingshearstressduringtheorganizationprocess.ThebedformdevelopmentcoefficientalsoispositivelycorrelatedwiththecriticalShieldsnumberandManning'sroughnesscoefficient,suggestingtheevolutionofflowresistancewithincreasingbedformdevelopment.Thesedimenttransportratedecreaseswithincreasingbedshearstressandbedformdevelopment,furtherillustratingtheeffectofbedstabilization.Anempiricalsedimenttransportmodelforanequilibriumconditionisproposedthatusesthebedformdevelopmentcoefficient,relativeparticlesubmergence(i.e.theratioofmeanwaterdepthandmaximumsedimentdiameter),modifiedbedslope,anddischarge.Themodelsuggestsbedformdevelopmentcanplayaprimaryroleinreducingsedimenttransport(increasingbedstabilization).ThemodelisanextensionofLane's(1955)relationspecificallyadaptedformountainstreams.Theseresultsexplainthesignificanceofbedformdevelopmentinheighteningflowresistance,stabilizingthebed,andreducingsedimenttransportincoarse,steepchannels.