新沟河延伸拓浚工程对长江水环境影响研究

新沟河延伸拓浚工程是国务院批复的太湖流域水环境综合治理重要工程之一。工程通过延伸拓浚新沟河排江通道，使江苏直武地区5 a一遇以下入太湖水改为北排长江，减少入太湖特别是入梅梁湖河道污染物输入。工程实施后新增排水将对河口处长江水环境造成一定的不利影响。利用MIKE21软件建立二维水流水质模型，重点研究了新沟河排水对长江水环境的影响。研究结果表明：工程排水对长江的不利影响主要局限在入江口附近区域，影响程度总体较小，但在极端情况下，影响较大，通过采取适当的生态修复、运行调度和水质监控措施可以予以缓解。

Research on influence of Xingou River dredging and extending project on water environment of Yangtze River

The Xingouhe River dredging and extending project is one of the important drainage projects that have been arranged by Comprehensive Management Plan of Water Environment in Taihu Basin that was approved by the State Council. Through the extending project, the 5-year flood or under in Zhiwu region is released into Yangtze River instead of Taihu lake, which would reduce the pollutant input into Meiliang Lake, a sub-lake of Taihu Lake. However, the newly increased drainage of Xingou River will impact Yangtze water environment. A two-dimension flow-pollutant simulation model was established based on MIKE21 and the impact on the water environment of Yangtze River was analyzed. The results show that the adverse effect mainly concentrates in the estuary region of Xingou River and the impact is slight in general and only serious in extreme case. The impact can be mitigated by measures of ecological restoration, operation dispatch and water monitoring.