长江口北支围垦对其水动力影响的数值模拟分析

20世纪50年代以来，上海市和江苏省两地对长江口北支实施了大规模围垦，使北支河宽大幅度缩窄，地形边界显著改变。在利用MIKE21_FM构建长江口—杭州湾二维垂向平均潮流数学模型，并用实测数据对模型进行验证的基础上，对北支大规模围垦前后的潮流场进行了模拟分析。研究结果表明：大规模围垦后，北支全河段平均高潮潮位抬升，平均低潮潮位降低；中上游河段涨、落潮流速增大，下游入海河段涨、落潮流速减小；南北支涨潮流汇流点上提至南北支交汇的崇头，涨潮动力增强。

Numerical simulation analysis of influence of reclamation of north branch in the Yangtze River estuary on hydrodynamic characteristics

The large-scale reclamation projects on north branch of Yangtze River estuary have been conducted by both Shanghai City and Jiangsu Province since 1950s,which has narrowed the river channel and changed the terrain boundary greatly.Using MIKE21_FM,a 2D hydrodynamic numerical model of vertical average tidal currents in Yangtze estuary and Hangzhou Bay is established.Based on the satisfied verification results,the tidal current field of north branch before and after the large-scale reclamations is simulated.The results show that after the large-scale reclamation,the average high tidal level of the entire river channel of north branch raised,while the average low tidal level declined;the velocity of flood and ebb tide in the middle and upper reaches increased;however the situation in the lower reaches is quite the opposite;With hydrodynamic force of the flood tide strengthened,the confluence of flood tide between south and north branches moved up to Chongtou where the South and North Branches converge.