ThecoastallowlandsinnorthernJiangsuProvince,China,ischaracterizedbylowreliefandlowwatersurfacegradientinstreams.Thefloodingstagesarecommonlylowerthanthehigh-tidelevelandthetidalrangeisrelativelysmall.Allthesefactorsprohibitrapiddischargeoffloodwaterandmakethefloodregimeshereextremelysensitivetothesealevelrise.The1991PlumRainwasexamined,whenprecipitationwassignificantlyhigherthannormal.Theone-dimensionalopen-channelnon-conservativeflowmodelwasusedtosimulatethestreamflowinthechannelnetworkofstudiedarea.GIStechnologywasusedtodelineatethemaximuminundatedareabyanalyzingtheDEMs.