简介：ThehugewinterstormofDecember23–29,2015deliveredheavyrainfallinabroadswathacrosstheUSA,delugingEast-CentralMissouri.Recordhighriverlevelsweresetatmanysites,butdamagesweremostpronouncedindevelopedfloodplainareas,particularlywherehighleveeswerebuiltorriverchannelsgreatlynarrowed.Anaverageof20cmofrainthatmostlyfellinthreedaysimpactedtheentire10300km2MeramecBasin.Comparedtothepriorrecordfloodof1982,thehighestrelativestage(+1.3m)onMeramecRiveroccurredatValleyParkproximalto(1)anewlevee,(2)alandfillinthefloodway,(3)largefloodplainconstructionfills,and(4)tributarycreekbasinsimpactedbysuburbansprawl.Eventhoughonlyasmallfractionofthe1.8millionkm2MississippiRiverwatershedaboveSt.Louisreceivedextraordinaryrainfallduringthisevent,thehugechannelizedrivernearandbelowSt.Louisrapidlyrosetosetthe3rd-highesttothehigheststagesever,exhibitingtheflashyresponsetypicalofamuchsmallerriver.