钱塘江九溪堤线优化对防洪御潮影响

杭州城西南排通道工程出口拟布置在钱塘江九溪岸段，为研究九溪岸段堤线优化对钱塘江防洪、御潮等功能的影响，采用平面二维数学模型，模拟工程实施后钱塘江百年一遇大潮、百年一遇洪水期间沿线的壅水高度、流速变化等情况。数值计算结果表明:当钱塘江遭遇百年一遇大潮时，工程区北岸堤前水位壅高相对明显，最大可达0.05 m，南岸的水位壅高影响小于0.01 m,南岸流速增加2%左右，上下游岸段堤前水域流速变化不大;当钱塘江遭遇百年一遇洪水时，工程河段局部范围内水位壅高0.02 m左右,下游相邻岸段堤前流速增加1%～2%，南岸浦沿排灌站岸段流速增加2%～3%，珊瑚沙水库围堤前沿流速影响较小。总体上，九溪岸段堤线优化对钱塘江防洪、御潮影响较小，对区域内地铁6号线、之江大桥、钱塘江大桥等涉水工程基本无影响。

Influence of Qiantang River Jiuxi embankment optimization on flood control and tide protection

Southwest drainage tunnel of Hangzhou City is a comprehensive water conservancy project to solve the problem of flood control and drainage in west Hangzhou.The exit of the project is to be located near the Yanshanhe sluice in Jiuxi section of Qiantang River.The Jiuxi section is located at the end of the estuary of the Qiantang River .Due to interaction of runoff and tide,the riverbed erosion and deposition of the section are relatively complex.However,after long term regulation,the width of the narrowest section of the section has been stabilized at about 1 km.This section of the river is relatively open,the north side of the flood embankment line can be appropriately optimized,combined with the implemented Hangzhou southwest drainage channel project,outlet drainage pumping station can get a comprehensive benefit.