Tidal Asymmetry Changes in a Shallow Mud Estuary by a Restoration Project

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摘要 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.
机构地区 不详
出版日期 2019年02月12日(中国期刊网平台首次上网日期,不代表论文的发表时间)
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