简介：ThehydrodynamicandthesedimenttransportpatternswithintheestuaryoftheYangtzeRiverarecomplexbecauseofinteractionoffluvialandthetidalforces,dependingonfreshwaterdischargeandtidalrange.Basedonthedatameasuredinrecentyears,thispaperdiscussesthecharacteristicsofflowandsedimentmovementintheYangtzeRiverEstuaryandtheirinfluencesontheevolutionoftheestuary.

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简介：Athree-dimensionalnumericalmodel,EFDC(environmentalfluiddynamicscode)isappliedtothePamlicoRiverEstuary(PRE)ineasternNorthCarolinaoftheUnitedStatestoexaminethewindimpactonpollutantagedistributionsandresidencetime.Aseriesofmodelexperimentsrepresentingbasecase,remote-wind-inducedwaterlevelset-upandlocalwindscasesareconducted.ModelresultsindicatethatthepollutantmeanageandthesystemresidencetimearefunctionsofgravitationalcirculationinthePRE.Thesystemresponsestoremote-wind-inducedwaterlevelset-uparedifferentindifferentportionsofthePRE.Undersuchcondition,dissolvedsubstancesintheupstreamportionofthePREhaveayoungerageandshorterresidencetime(comparedwiththebasecase),bycontrast,theyhaveaolderageandlongerresidencetimeinthedownstreamportionofthePRE.Upriveranddownriverlocalwindsappeartohaveoppositeimpactsonpollutantagedistributions.ThesubstancesareretainedmuchlongerwithinthePREunderupriverwindthanthoseunderdownriverwind.Themodelresultsalsosuggestthatacross-riverwindsmayleadtolongerresidencetimethroughenhancedturbulencemixing,whichslowsdownthegravitationalcirculationinthePRE.

简介：BasedonthebiogeochemicalstudiesonnutrientelementsintheChangjiangestuary,themainresultsandrecentprogressesarereviewedinthispaper,suchasthenutrientfluxesintothesea,themixingbehaviors,thedistributioncharacteristicsandtransportationaswellasthebiogeochemicalbehaviorsofnutrientsintheplumefrontalregion.Theexploringdirectionsandresearchemphasesinthefutureareproposed.

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简介：Aseriesofadvancedinstrumentswereappliedtoobtainthefielddataofbed,bedformsandrelevantdynamicfactorsinthe150km-longreachoftheChangjiangRiverfromJiangyintoHengshaIslandinMarch2002.Wefoundthatwell-sortedfinesandwasinthemajorityofthebedsediment,whichhadamediandiameterof2φ.Well-developedsandwaveswereformedbecausethegrainsjumpedtogetheronthebed,whichwasrelatedtothegranularityandcurrentvelocityduringtheflood-ebbtidalcycles.

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简介：ThefirstChineseexperimentalwavepowerplant,i.e.,theshoremountcdexperimentalwavepowerplantatthePearlRiverEstuarywassuccessfulintrialpowergenerationonFebruary15,1990.TheplantisonthesouthshoreoftheDawanshanIslandinthePearlRiverEstuary,facingthevastwavingSouthChinaSea.WithadesignedwaveconditionofH1/10=1.5mandT=6.5s,theplannedinstalledcapacityis8kWcomprisingthefirstunitof3kWbrushlessclawpolegeneratorwhichdelivers110VDCcurrentandthesecondunitof5kWbrushlesssinglephasesynchroACgeneratorwhichdelivers220VACcurrent.Atpresent,thefirstunithasbeenputintotrialoperation.

简介：-BasedonthefeasibilitystudyofdevelopingthenavigationresourcesoftheGuanheRiverandthemodeltestresultsofthemouthbarregulation,thispaperpresentssomebasicprinciplesfortheregulationofthechannelonthemouthbar,forinstance,thedirectionofnavigationchannelshouldbeidenticalwiththatoftheebbtidecurrentandthemainwaves,andperpendiculartothebathymetriccontours.Theprinciplesforregulatingmouthbarsarealsodiscussedinthispaper.

简介：ThecircumfluencearoundtheJiuduanSandbankisthoroughlystudiedbymeansoftheprinci-pleofleastresistanceinfluiddynamics.ThediversionratiooftheNorthChannelfor1998iscalculated,whichisalmostthesameasthefieldsurveydata.ThenormalandminimumdiversionratiosoftheNorthChannelafterstagesⅠ,ⅡandⅢregulationworksaswellasthefuturephaseareobtained.Thenumeri-calresultsandpredictedvalueareaccurate.

简介：-ThispaperdescribesaradioactivetracerexperimentcarriedoutatthelandwardspoilsiteoftheNorthPassageintheYangtzeEstuaryinJune,1991.Scandium-46wasselectedasthetracer,thetotalactivityreleasedwas179.45GBqandtheamountoftheSandium-46glasswas495g.Thepurposeoftheexperimentwastodeterminethesedimentmovementdirection,path,velocityandtransportrate,andtherefore,toprovidedirectevidenceforusingthelandwardspoilsiteinthefuture.Theexperimentalresultsshowedthatthesedimentmovementwasgovernedbytheebbtidecurrentduringtheperiodofmeanandneaptideswhentheradioactivetracerwasinjectedbothonthefloodandebbtides,andthesedimentmovedfromthereleasepointtothemiddleoftheNorthPassagenearnavigationbuoyNo.269.Thedirecitonofthesedimentmovementwas110°,theparticlevelocitywas758m/d,andthesedimenttransportrateperunitwidthwas47.8m3/md.

简介：BasedonanalysesofsurfaceandcoresedimentsinthetidalflatsoftheYangtzeEstuaryandcoastalareas,thepresentstudyrevealsphosphorousformsexistinginsedimentsandtheirdistributions.Theresultsshowthatphosphorusintidalflatsedimentsinthestudyareamainlyconsistsofinorganicphosphorousforms,involvingDP,Fe-P,Al-P,andCa-Pandorganicphosphorousforms,inwhichCa-PandOParedominantcompositions.Thisfindingindicatesthatspatialdistributionsofvariousphosphorousformsarerelatedtosedimentaryenvironmentsinwaterandgrainsizesofsediments,andareinfluencedbysewagedischargesandeffluentsfromaquacultivationinthecoastalareas.

简介：DuringtheconstructionoftheguidingdikeintheYangtzeEstuary,someofthecaissonstructuressankintothesoilfor1～5morslidabout20mawayfromtheoriginalplacewhenastrongstormattackedthisarea.Dynamictriaxialtestswerecarriedouttosimulatethebehavioroffoundationsoilsunderwaveloading.Thetestresultsshowthattheexcessivesettlementandlateralmovementofthecaissonsareduetotheweakeningofthesoftclaystrengthduringthestrongstorm.Thetestresultsalsoshowthattheabilityofthesoftclaytoresistthewaveforcewillbegreatlyincreasedwhenthesoftsoilsamplesaresuitablyimproved.Basedonthetestresults,animprovementmethodcombiningverticaldrainswithsurchargeloadingwasproposedtostrengthenthefoundationsoil.Ontheimprovedsoilfoundation,thedikehasbeenreconstructedandundergoneseveralstrongstormswithoutanydamage.Afiniteelementapproachhasbeendevelopedforanalyzingthesettlementandstabilityofthedikeundertheactionofstrongstorm.

简介：NanxiaohongandNangangmainsouthchannelarechosenasthetypicalfloodandebbchannels.HydrodynamicsanalysisbasedonfieldhydrologicalandsedimentdataisconductedwithGao-Collinsmodeltoanalysesedimenttransporttrends.Also,thegrainsizedistributionanalysisofthebottomsedimentsampledinSep.2001isusedasthebaseoftheanalysis.TheresultshowsthatthesedimentinNanxiaohongisfromtherivemoutharea.Thesedimenttransportsupwardswiththefloodflowwhichisstrongerthantheebbflow,i.e.,inthedirectionofSE-WN.Thesedimentinmainsouthchannelcomesfromupward.Theytransportdownwardswiththeebbflow,whichisstrongerthanthefloodflow,i.e.,inthedirectionofWN-SE.Thedirections,sourcesandmechanismofsedimenttransportareidentifiedaccordingtocomprehensiveanalysesoftheobserveddataonhydrodynamicsandsediment.

简介：在河口和沿海的环境的关键担心之一是超营养作用，它被知道仔细被连接到滋养的丰富。为了控制并且改善表面水，优秀、滋养的标准被建议以便为环境提供参考条件。然而，在中国的滋养的标准的当前的数据集也为表面水或海水被设计，并且作为这，这些不对估计河口水质量合适，特别给唯一的生态系统和河口的动态性质。为了在当前的河口处理这期，浇管理，滋养的标准在中国的东南为一个本地河口被开发了。Jiulong河河口的分割，中国第一通过在2013-2014期间执行的地调查被分析，它导致了他们的不同性质在与咸度的关系描绘的三个片断的描述，水文学，生态系统，等等。从1997～2014的历史的记录然后用统计建模被分析为河口开发候选人营养素标准。分析的这个阶段从1980年代与滋养的地位记录的学习在联合被承担，它被用来建立一个基线参考条件。在片断的溶解的无机的氮(吵闹)的推荐标准价值分别地，Jiulong河河口的，II和III是64，21和14mol/L，为可溶的反应的磷(SRP)的相应价值分别地是0.89，0.76和0.89mol/L。这些价值是，这应该被强调地点依赖者，和那不同结果可以在取决于的另外的地点被完成物理并且一个河口的biogeochemical特征，或甚至在集水以内的一个单个地点。由在Jiulong河河口表明滋养的标准推导的一条可能的方法学的途径和方法，当前的学习将为研究人员提供开始在整个中国在另外的河口为滋养的条件的学习开发更完全的滋养的标准索引的某基本基础，这被希望。

简介：TheChangjiangEstuaryisthedoorwayoftheShanghaiHarbourandthethroatforthesixprovincesintheChangjiangRiverdrainagearea.Howevertheminimumwaterdepthofthewaterwayintheestuaryisonlyaboutsixmeters,sothatthedevelopmentoftheShanghaiHarbourandtheutilizationofwatertransportationontheChangjiangRiverhavebeengreatlyrestrained.Since1975,thedepthofthesea-enteringwaterwayoftheChangjiangEstuaryhasbeensuccessfullyincreasedbyonemeter.Thisarticlehasmadeacomprehensivesumming-upabouttheselectionofwaterways,thedeterminationofthelinefordredginganddisposalofthedredgedmaterial,thusprovidingreferencedataforfutureworkinincreasingthedepthofthewaterwayoftheChangjiangEstuaryandforcontrollingsimilarwaterwaysofotherestuaries.

简介：Thebed-loadmovementandtheevolutionoftheChangjiang(Yangtze)EstuaryarestudiedbyusingthegeographicinformationsystemandtheremotesensingimageprocessingsoftwareAnalysisontheerosionandsiltationoftherivermouthisperformedfortheperiod1988-2000.Thepossiblelocationandthicknessofthefuturedepositionareasintheestuarinechannelsarepredicted.

简介：ThemacrobenthiccommunityoftheXiaoqingRiverEstuaryandtheadjacentseawaterswasinvestigatedinMayandNovember2008,August2009,andMayandSeptember2010,respectively.Atotalof95speciesofmacrobenthoswereidentifiedinthefivecruisesandmostofthemwerepolychaetes(46.39%),mollusks(28.86%)andcrustaceans(20.62%).TheShannon-Wienerindexofmacrobenthoswaslowerthan2in67%sites.Alongthestreamchannel,estuaryandthecoastalwaters,thespeciesofpolychaetesreducedgradually,whiletheabundanceincreasedatfirstandthendecreased.Theabundancewasthebiggestatregionswithsalinityof520intheestuary.Thespeciesandabundanceofmollusksandcrustaceansincreasedgradually.Asforseasonaldistribution,thespecies,abundanceandbiomasswerehigherinspringandlowerinsummerandautumn.ContemporaneouslycomparedwithLaizhouBayandYellowRiverEstuary,thespeciesofmacrobenthosappearedintheXiaoqingRiverEstuaryweremuchless,whilethepercentageofpolychaeteswashigher.AbundanceandbiomasswerehigherinXiaoqingRiverestuary,thenconsequentlyfollowedbyLaizhouBayandYellowRiverEstuary.ThedominantspeciesinXiaoqingRiverEstuarywaspolychaete,andLayzhouBaymollusk.ThecommunitystructurecharacteristicsofmacrobenthosintheXiaoqingRiverEstuaryrevealedasignificantpollutionstatusinthisregion.

简介：Thetidalasymmetry-inducedsiltationbelowtidalbarriersisaworldwideproblemthatrestrictsregionalsocio-economicandenvironmentaldevelopment.Thehydrodynamicprocessesofthesmallmudestuaryalsofeatureahighuncertaintyafterestuaryrestorationmeasures.Inthisstudy,ahydrodynamicmodelbasedontheMIKE21isusedtoquantifytheresponsesoftidalasymmetrytoatwo-phaserestorationprojectinShuanglongEstuary,BohaiBay,China.Accordingtothenumericalmodelingresults,thetidalflatremovalintheupperestuary(first-phaserestoration)inducesthefloodasymmetryswitchingtotheebbasymmetryinunrestoredreachbutenhancesfloodasymmetryinwideningrestoredreach.Althoughthetidalasymmetryrevertstoflood-dominatedpatternafterfullrestorationovertheestuary,theimbalancebetweenfloodandebbvelocitiesisrelieved.Apossiblenetsedimenttransportpatternbasedonacomparisonofdominantasymmetriccurrentandactualsedimenttransportperiodshowsnetsedimentsintheupperestuaryandinlettransportseawardandlandward,respectively,inthefirst-phaserestoration,whereaslandwardnetsedimenttransportoccursinthewholeestuaryunderthesecond-phaserestorationscenario.Giventheseresults,weassumethataswitchfromtheflood-dominatedestuarytoebb-dominatedestuarycanbecausedbyredesigningthecross-sectionalprofile.ThequantitativecomparisonofLagrangianresidualcurrentsalsoimpliesthatachannel–shoalstructureratherthanaflatbathymetrycanpromotethemasstransport.Therefore,reshapingthechannel–tidalflatsysteminrestorationprojectscanpreventthesedimentationoftheestuaryandimprovethewaterenvironment.