太湖不同湖区底泥悬浮沉降规律研究及内源释放量估算

J．LakeSci．(湖泊科学)，2014，26(2):191-199http://www．jlakes．org．E-mail:jlakes@niglas．ac．cn2014byJournalofLakeSciences太湖不同湖区底泥悬浮沉降规律研究及内源释放量估算*胡开明1，2，王水1，2，逄勇3(1:江苏省环境科学研究院，南京210036)(2:江苏省环境工程重点实验室，南京210036)(3:河海大学环境学院，南京210098)摘要:太湖是一个大型浅水湖泊，湖湾、沿岸及湖心等区域受地形影响，湖流结构及水土界面水力要素均有显著差异．针对目前对不同湖区底泥再悬浮规律差异性研究的缺失，本研究选取了3个具有代表性的点采集太湖底泥，采用矩形水槽开展底泥再悬浮模拟实验，并结合太湖二维水量水质模型及太湖全年实测数据，建立了不同湖区底泥再悬浮通量与风速之间的定量关系;通过室内静沉降实验，得到了静沉降通量与风速的相关关系;最后将底泥再悬浮实验结果参数化应用于太湖二维水量水质模型中，并对底泥悬浮沉降过程进行分解和概化，估算太湖全年内源释放量．结果表明:太湖每日的内源释放量受风速影响显著，和风速变化趋势较为接近，太湖全年进入水体的净底泥量有47．81×104t，夏季最大，冬季次之;就营养物质释放量而言，COD约为2．06×104t、总氮约为1149．05t、总磷约为564．35t，其中秋季营养物质释放量最小，夏季最大．关键词:底泥释放;内源;再悬浮;矩形水槽;太湖Suspension-sedimentationofsedimentandreleaseamountofinternalloadinLakeTaihuHUKaiming1，2，WANGShui1，2＆PANGYong3(1:JiangsuProvincialAcademyofEnvironmentalScience，Nanjing210036，P．Ｒ．China)(2:JiangsuProvincialKeyLaboratoryofEnvironmentalEngineering，Nanjing210036，P．Ｒ．China)(3:CollegeofEnvironment，HohaiUniversity，Nanjing210098，P．Ｒ．China)Abstract:Asalargeshallowlake，LakeTaihuexhibitssignificantdifferencesinflowstructuresandhydraulicfactoratwater-soilinterfaceduetodifferentterrainsinlake-bay，coastalandcenterarea．SedimentreleaseunderdifferentflowvelocitiesfromthreesitesinLakeTaihuwassimulatinginarectangleflumetostudysedimentresuspensionundervarioushydrodynamicconditions．Combinedwiththein-situtestandexperimentinthelaboratory，a2-Dmodelofwaterflowandwaterqualityonwind-drivencurrentinLakeTaihuwasestablished．Thesedimentresuspensionfluxandsettlingfluxfromdifferentlakeregionsinthefourseasonswerecalculatedandtherelationshipsbetweenthesefluxesandwindspeedwereobtained．Theexperimentresultwasappliedinthenu-mericalmodelandthesuspension-sedimentationprocesswasdecomposedandgeneralizedaccordingtothecriticalwindspeed．An-nualaveragereleaseamountofinternalloadinLakeTaihuduringtheyear2009wasestimated．Theresultsindicatethatdailyre-leaseamountofinternalloadinLakeTaihuwassignificantlyinfluencedbywindandhadthesametrendofchangewithwind．LakeTaihuhasanannualaveragereleaseamountof