简介：ThisarticleaddressessedimentresearchcarriedoutfortheThreeGorgesProjectsince1993,whentheconstructionoftheprojectwasformallystarted.Emphasisoftheresearchhasbeenplacedonthesolutionofrelevantproblemsarisingfromdesignandconstructionofvariousstructures,includingsedimentationproblemsintheChongqingreach;layoutoftheupperlockapproachchannelandwaysandmeanstomitigateitsdeposition;increasingreservoircapacitybyoptimizingreservoiroperation;compensatingdepthofflowrequiredbynavigationbelowtheGezhoubaProjectcausedbyscouring;mitigationofadverseeffectsoferosiononthereachfromZhichengtoJiangkou;andevaluatingscouroftheJinjiangreachcausedbyreleasingflowsoflowconcentrationsfromtheTGP.Inaddition,reductionofthesedimentloadenteringintothereservoirareaoftheTGPintherecentyearsaswellasthatexpectedoftheprojectedconstructionoflargehydropowerstationsontheJinshaRiverupstreamoftheTGPreservoirisalsonotedanddiscussed.

简介：SedimentsupplytothelowerJingjiangRiverwillbesubjecttosubstantialreductionaftertheimpoundmentoftheThreeGorgesReservoir,whichcouldresultinanexcessofcarryingcapacityandseriousbankerosionsinthedownstreamalluvialchannel,threateningthebankprotectionworksandthesafetyoftheJingjiangDyke.ThispaperpresentsasummaryofresearchworksconcerningthefluvialprocessesinthelowerJingjiangRiverandthepossibleimpactoftheThreeGorgesReservoirimpoundmentonthevariationofitschannelpattern.Threedifferentpredictionshavebeenputforwardbyresearchers:1)theJingjiangRiverwillevolvetowardsamoresinuous,meanderingchannelpattern,withextensivebankerosiontakingplacealongtheriver;2)theriverchannelwillbestraightenedandbroadenedbecausenopointbarcanbeformedduetoreducedsedimentsupplywhilebankerosiondevelopsintheconcavebank,and3)thisriverreachwillmaintainitspresentchannelpatternwithoutsignificantchange,althoughthesinuositymaybeslightlyreduced,since:a)theThreeGorgesReservoirmainlyinterceptsedimentparticleswithsizeslargerthan0.025mm,andb)thecomplexinteractionbetweentheYangtzeRiverandtheDongtingLakehelpstoreducethenegativeeffectofchannelerosionthroughcertainself-adjustingmechanisminfluvialprocesses.DiscrepancybetweenthesepredictionsshowsthatfurtherresearcheffortsareneededtounderstandtheimpactofThreeGorgesReservoiroperationonthedownstreamfluvialprocesses.Meanwhile,thereisanurgentneedtocloselymonitorfuturedevelopmentinthefluvialprocessesoftheJingjiangRiveranditsinfluenceonthesafetyoftheJingjiangDykes.

简介：Thispapersummarizesthelatestdevelopments,futureprospects,andproposedcountermeasuresofreservoirsedimentationandchannelscourdownstreamoftheThreeGorgesReservoir(TGR)ontheYangtzeRiverinChina.Threekeyresultshavebeenfound.(1)TheincomingsedimentloadtotheTGRhasbeensignificantlylowerthanexpected.(2)TheaccumulatedvolumeofsedimentdepositionintheTGRissmallerthanexpectedbecausetheoverallsedimentdeliveryratioisrelativelylow,andthedepositioninthenear-damareaoftheTGRisstilldeveloping.(3)RiverbedscourintheriverreachesdownstreamoftheGezhoubaDamisstilloccurringandchannelscourhasextendedtoreachesasfardownstreamastheHukoureach.Significantly,sedimentationoftheTGRislessproblematicthanexpectedsincethestartofoperationoftheTGRontheonehand;ontheotherhand,thepossibleincreasesinsedimentrisksfromdependenceonupstreamsedimentcontrol,depositioninthereservoir,andscouralongmiddleYangtzeRivershouldbepaidmoreattention.(1)SedimenttrappedbydamsbuiltalongtheupperYangtzeRiverandbilliontonsofloosematerialsonunstableslopesproducedbytheWenchuanEarthquakecouldbenewsedimentsourcesfortheupperYangtzeRiver.Moreseriously,possiblereleaseofthissedimentintotheupperYangtzeRiverduetonewearthquakesorextremeclimateeventscouldoverwhelmtheriversystem,andproducecatastrophicconsequences.(2)IncreasingsedimentdepositionintheTGRisharmfultothesafetyandefficiencyofprojectoperationandnavigation.(3)ThedrasticscouralongthemiddleYangtzeRiverhasintensifiedthedown-cuttingoftheriverbedanderosionofrevetment,ithasalreadyledtoincreasingrisktofloodcontrolstructuresandecologicalsafety.ItissuggestedtocontinuetheFieldObservationProgram,toinitiateresearchprogramsandtofocusonrisksofsedimentation.

简介：基于阻抗张肌数据，tipper数据，和conjugate坡度算法的分析，我们发展一三维(3D)为转换结合坡度算法完整的信息数据决定了从的magnetotelluric五电并且磁场部件并且讨论方法为3D倒置结果的量的解释使用完整的信息数据。从合成数据的3D倒置的结果显示从转换的结果更好联合张肌和tipper数据是的阻抗比的完整的信息数据源于转换仅仅阻抗张肌数据(或tipper数据)在改进分辨率和可靠性。合成例子也表明这个3D倒置算法的有效性和稳定性。

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简介：基于测量系统的3DPTV(追踪Velocimetry的粒子)，有四条不同直径的粒子的3D运动特征被调查。在特定的流动条件下面，粒子的3D运动上的粒子直径的影响被学习，并且骚乱特征被不同统计方法分析。当直径增加了，结果证明粗糙的粒子的骚乱紧张减少了。在近的墙区域，纵、垂直的变化速度的概率密度分布两个都从正常分发背离了；当时在外部区域，垂直变化速度的概率密度分发近似同意了正常分发。

简介：当前，大多数MT(magnetotelluric)数据仍然在稀少的调查线上被收集并且因为域工作费用，解释了使用2D倒置方法，工作区域环境等等。然而，有从总是导致错误地地质的解释的3Dgeoelectrical结构的MT数据的一些2D解释限制。在这份报纸，我们使用了3D倒置方法解释MT稀少的线数据。在模型测试，稀少的行数据是从一个测试模型产生并且处理了使用3D的MT完整的信息数据结合坡度倒置代码。倒置结果证明这个倒置方法合理、有效。同时，我们证明为有不同元素参数的倒置结果，由阻抗张肌数据和tipper数据的联合倒置的结果对测试模型更精确、更靠近。

简介：TostudythecharacteristicsofthedistributionofthepreferentialpathsandtheaffectingfactorsintheThreeGorgesarea,foursoilprofilesweredugtoobservethedistributionofpreferentialpathsintheQuxiwatershedintheYangtzeRiverbasin.TheMorisitaexponentialtestmethodwasusedtoexaminethedistributiontypeofpreferentialpaths.Thephysicalpropertiesandinfiltrationcharacteristicsofthesoilwerealsomeasuredtoevaluatetheirrelationshiptopreferentialpaths.Theresultsshowedthatinthisarea,preferentialpathsclusteredandmainlydistributedinthe80-100cmsoillayer,andalongtheinterfacebetweentheweatheredlayerandsemi-weatheredlayer.Thereweremorenon-capillaryporesinthe83-110cmlayerthanintheotherlayers.Itcanbederivedthatmostnon-capillaryporesinthislayerwerepreferentialpathscausedbygeologicalprocessesandrottenplantroots.Thepercentageofcoarsesoilparticlesincreasedwiththedepthofthesoillayer.Inthedeepersoillayer,thecoarsesoilparticleshelpedtheformationofpreferentialpaths.Thefasteststeadyinfiltrationratewasobservedintheof83-110cmlayer,whichisinferredtobeduetothegreaternumberofpreferentialpaths.

简介：然而，物理土壤外壳几乎多半没在渗入和土壤侵蚀上有重要效果在外壳的效果是否在一个降雨事件期间变化上被知道。进一步，有在不同土壤类型的crusting效果之中的差别的讨论的缺乏。这研究的目的如下：在中国用三典型土壤在渗入，流量，和骚动侵蚀上学习土壤外壳的效果的(i)，(ii)玷污在三的水文学和侵蚀上区分不同效果并且为这些差别讨论主要原因，并且(iii)砍在真实土壤理解变化三的力量在降雨事件期间并且算术地玷污在土壤侵蚀上为外壳的效果建模。这研究证明土壤外壳由5～15min推迟了渗入的发作并且在降雨事件期间在42.9～53.4%减少了渗入的全部的数量。为紫色土壤和黄土土壤，分别地，起始的外壳增加了流量2.8%和3.4%并且分别地在3.1%和8.9%减少了骚动侵蚀。为黑土壤，土壤外壳增加了流量42.9%并且出人意料地增加了骚动侵蚀95.2%。一般来说，紫色和黄土土壤上的外壳的效果类似、可以忽略，但是效果为黑土壤是重要的。土壤砍力量在降雨事件期间动态地并且逐渐地减少了，并且crusted土壤的价值比incrusted土壤的那些高，特别在降雨的早阶段期间。数学模型被开发如下为三土壤在骚动侵蚀上描述土壤外壳的效果：紫色土壤，Fc=0.002t−0.384；黑土壤，Fc=0.002t+3.060；并且黄土土壤，Fc=0.2331nt−1.239。与方程Rc=Fc·（Ruc−1)，crusted土壤的骚动侵蚀能随着时间的过去被预言。

简介：TheThreeGorgesProject(TGP)isaworldknownprojecttoutilizeandmanagethewaterresourcesoftheYangtzeRiver.Thereservoirstoreswaterattheendofthefloodseason,andreplenishesdownstreamreacheswithwaterindryseasons.Inadditiontosuchbenefits,theTGPhasirreversiblychangedthehydrologicalprocessandtheriver-lakerelationofthemiddleandlowerreaches.Inthispaper,ahydrodynamicmodelwasestablishedtoquantifytheimpactoftheTGP'soperationonthewaterexchangebetweenDongtingLakeandtheYangtzeRiverduring2009–2013.Theresultsindicatedthat:theoperationoftheTGPhasconsiderablyreducedthepeakdischargeandthefloodvolumeofthemainstreamandtheDongtingLakearea.TheinflowvolumefromtheYangtzeRivertoDongtingLakeviathreeoutletsdecreasedby1.9–3.5billionm3/yr,whiletheoutflowvolumefromDongtingLaketotheYangtzeRiveratChenglingjiincreasedby0.3–1.6billionm3inSeptemberand0.4–0.6billionm3inOctober,respectively.Thisresearchprovidesvaluableinformationforfloodcontrol,irrigation,andwaterallocationinthemiddleandlowerreachesoftheYangtzeRiver,andservesasatypicalcaseforinvestigatingtheimpactofotherhydropowerprojectsaroundtheworld.&2017InternationalResearchandTrainingCentreonErosionandSedimentation/theWorldAssociationforSedimentationandErosionResearch.PublishedbyElsevierB.V.Allrightsreserved.

简介：把系统基于追踪Velocimetry(3DPTV)的三个维的粒子，有四条不同直径的粒子的运动的特征在稳定的流动条件下面被调查。这些粒子的纵的平均速度侧面根据木头法律，当垂直、横向的速度与最小的变化仍然保持很低时。在床负担层的粒子的时间一般水准速度是8.50u*，近到Bagnold的假设Un吗？ω。在暂停区域的粒子的垂直集中分发同意了Rouse方程。当粒子的直径相对大时，在那里存在在床负担层的一个明显的集中坡度。

简介：一个三维的数字模型在现在的纸被开发，旨在模仿处于不连续的状况的推迟的沉积运输。在模型，推迟的沉积的移流散开方程基于未组织的网孔用紧缩的不连续的Galerkin(CDG)方法被解决。模型的评估揭示了在建议模型和存在理论之间的好同意。模型有秒顺序精确性。而且，模型被用于引起由的推迟的沉积运输的一个理想化的盒子基于这块地撕破水流空间规模。

简介：Themodelingandpredictionofsuspendedsedimentinariverarekeyelementsinglobalwaterrecoursesandenvironmentpolicyandmanagement.Inthepresentstudy,anAdaptiveNeuro-FuzzyInferenceSystemmodeltrainedwiththeLevenberg-Marquardtlearningalgorithmisconsideredfortimeseriesmodelingofsuspendedsedimentconcentrationinariver.ThemodelistrainedandvalidatedusingdailyriverdischargeandsuspendedsedimentconcentrationdatafromtheSchuylkillRiverintheUnitedStates.TheresultsoftheproposedmethodareevaluatedandcomparedwithsimilarnetworkstrainedwiththecommonHybridandBack-Propagationalgorithms,whicharewidelyusedintheliteratureforpredictionofsuspendedsedimentconcentration.ObtainedresultsdemonstratethatmodelstrainedwiththeHybridandLevenberg-Marquardtalgorithmsarecomparableintermsofpredictionaccuracy.However,thenetworkstrainedwiththeLevenberg-MarquardtalgorithmperformbetterthanthosetrainedwiththeHybridapproach.

简介：地上凿穿表面的3D倒置为复杂geo电的模型的电的数据仍然是在地球物理的探索的一个挑战性的问题。我们为3D倒置开发了一个节目到地上凿穿表面电的数据基于伪分析的近似(质量保证)并且re加权调整结合坡度方法(RRCG)用视觉Fortran6.5的算法。到向前当模特儿和Frechet衍生物计算的QA近似的申请戏剧性地加快计算。为理论模型的合成数据的试用计算证明程序快、高度精确。

简介：河健康能被定义为河流的精力来源，水质量，流动政体，产地和生物区系匹配自然条件到的度。在一条健康的河里，物理过程和形式遗体活跃地连接了并且能互相调整、生物社区有差异的自然层次并且对环境应力有弹性。物理差异和生物多样性影响河健康。物理差异被水文学，hydraulics，和底层管理，在河隧道和邻近的泛滥平原的几何学思考了它为水、河边的有机体创造产地。生物多样性被象竞争和predation那样的生物过程管理，但是生物多样性也反映产地，以及连接的差异，丰富和稳定性。在一个河走廊以内的连接包括纵、侧面、垂直的尺寸。当任何这些交往的部件被人的活动损害，河健康衰退。水坝的累积效果和河的另外的人的改变主要是直接减少物理差异和连接，它间接地减少生物多样性。在水坝影响的河里的物理差异和生物多样性的恢复和维护要求在流动和沉积的驱动程序变量之间的确定的关系供应，和产地，连接，和生物社区的反应变量。这些关系能拿阀值的形式(例如，streambed沉积的乘火车)或反应曲线(例如，泛滥平原淹没的鱼生物资源对程度和持续时间)。我在西方的美国从怀俄明，科罗拉多，和亚利桑那使用例子说明怎么确定在在河里的司机和反应变量之间的关系由水坝影响了。

简介：AfteroperationoftheThreeGorgesProject(TGP),thereisanewevolutiontendencyforriversandlakesinthemiddlereachesoftheYangtzeRiver(i.e.theChingRiverreaches).Inrecentyears,theweakeningconnectionrelationshipbetweentheYangtzeRiverandDongtingLakehasresultedinaseriesofproblemsforfloodregulation,waterresourcesutilization,andaquaticecosystemprotectionintheriver-lakejointarea.Inthispaper,thehydrologicalcharacteristicsandfluvialprocesseswithintheriver-lakejointareaarestudied,andpossiblemanagementstrategiestomaintaintheconnectedriver-lakerelationshipareproposed.Toachievethisobjective,theevolutiontendency,suchasthezero-flowproblemandriverregimeforthreemajoroutlets(i.e.theSongziOutlet,TaipingOutlet,andOuchiOutlet)toDongtingLakefromtheYangtzeRiver,isanalyzed.ItisbelievedthattheSongziOutlethasacomparativeadvantageinflowdiversionovertheothertwooutlets.TheRangeofVariabilityApproachisintroducedtoidentifyhydrologicalcharacteristicsattheSongziOutlet.Severalcharacteristicvaluesofflowdiversionfromthisoutletduringdroughtperiodsaredetermined.Then,thefluvialprocessesintheriver-lakejointareaarestudiedbycomparingtopographicmapsandusingcontrolgaugestationdataofvariousyears.ThewaterandsedimentfluxareanalyzedbeforeandafteroperationoftheTGP.Finally,basedontheresultsobtained,twopossiblemanagementstrategiesarerecommendedandcorrespondingparametersareestimatedtostrengthenandmaintaintheconnectedriver-lakerelationship.ThisanalysistakesintoaccountoperationoftheTGP,mainstreamshiftandincreasingriverbedscourintheChingRiverchannel.Torestoretheflowdiversionconditiontothatinthe1950sor1960s(i.e.140m3/sofflowdiversioncorrespondingto5500m3/sofflowattheZhichengstation),itisestimatedthattheriverchannelaroundtheSongziOutletshouldbedredged1.4munderthecurrentriverbedsituatio

简介：Asemi-implicit3-Dnumericalformulationforsolvingnon-hydrostaticpressurefree-surfaceflowsonanunstructured,sigmagridisproposed.Pressure-splittingand9semi-implicitmethodsareinheritedandreformedfromCasulli'sz-coordinateformulation.Thenon-orthogonalsigma-coordinatetransformationleadstoadditionalterms.Theresultinglinearsystemforthenon-hydrostaticcorrectionisdiagonallydominantbutunsymmetric,anditissolvedbytheBiCGstabmethod.Incontrastwithz-coordinatenon-hydrostaticmodels,thenewmodelfitsverticalboundariesmuchbetter,whichisimportantforthelong-timesimulationofsedimenttransportandriverbeddeformation.Alock-exchangedensityflowiscomputedtodeterminewhetherthenewschemeisabletosimulatenon-hydrostaticfree-surfaceflows.ThenewmodelisfurtherverifiedusingthefielddataofanaturalriverbendofthelowerYangtzeRiver.Goodagreementbetweensimulationsandearlierresearchresults,fielddataisobtained,indicatingthatthenewmodelisapplicabletohydraulicprojectsinrealrivers.

简介：Thepaperpresentsthe3DfiniteelementsimulationoftidalflowandSedimenttransportintheestuarineregionoftheHaiheriver.Theproposedmodeladoptssigma-transformationofthehydrodynamicandsedimenttransportequations.Thehydrodynamicandsedimenttransportmodelsareverifiedincaseofasimpletestproblemforwhichanalyticalsolutionsareavailable.FinallythemodelsareappliedtomuddyHaiheriverestuaryofNorthChinaanditisclaimedthathydrodynamicandsedimenttransportmodelsgiveareliablecomparisonwiththeobservedfielddata.However,therearecertaindiscrepancies,andsomereasonablequestionsregardingthepresentstate-of-art,inthemodelingofthree-dimensionalmultilevelhydrodynamicsandsedimenttransport,whichareprovidedbelowforanswer.