普兰店湾潮滩养殖围堰工程拆除前后水动力特征的数值分析

普兰店湾四周大量的滩涂逐步被开发成海参及贝类围堰养殖池塘，致使普兰店湾出现自然岸线不断萎缩、水体交换通道堵塞等系列问题，通过拓宽海湾水体交换通道恢复其水文和水动力条件是重要的手段之一。文章采用 MIKE21 模型对普兰店湾的潮流分布特征进行数值模拟，在潮位、流速模拟验证的基础上，对比分析了养殖围堰拆除工程实施前后普兰店湾的水动力情况。结果表明：养殖围堰拆除区域的局部滩涂流速增大，其值在0.3~0.4 m/s左右变化，围堰拆除对于距离在1.5 km以内的海域有一定影响，而对较远的金州湾及外海的整体流场基本无影响；拆除养殖围堰拓宽了普兰店湾的水域面积，提高了湾内的涨落潮流速，湾内的纳潮量增大了8.535%，位于北岸的养殖池拆除区域流场呈现明显的潮滩特征，上述变化有利于加快潮滩上盐沼植物、海洋生物生境的营养物质交换。

Numerical Analysis of Hydrodynamic Characteristics for Removal of Culture Cofferdam in Pulandian Bay

A large number of tidal flats around Pulandian Bay have gradually been developed into cofferdam ponds of Sea Cucumber and shellfish, which have resulted in a series of problems such as shrinking natural coastlines and blocking water exchange channels in Pulandian Bay. One of the important means is to restore the hydrologic and hydrodynamic conditions by widening the water exchange channel in this Bay. In this paper, the MIKE21 model was used to simulate the distribution characteristics of tidal current in the Pulandian Bay. Based on the simulation and verification for tidal levels and tidal velocities, the hydrodynamics of Pulandian Bay were compared under the different conditions before and after the project. The results showed that the increase of tidal current velocity was about 0.3 ~ 0.4 m/s inside of the culture cofferdam removal area, and the removal of the cofferdam had some influence on these areas within 1.5 km. However, it had no effect on the flow field of other areas far away from Pulandian Bay in distant Jinzhou Bay and the open sea. The removal of the culture cofferdam broadened the water areas of Pulandian Bay and increased the ebb and flow velocities in this bay, the tidal prism was increased by 8.535% after the project. The flow field in the north side of removal area showed obvious tidal flat characteristics, which was beneficial to the nutrient exchange for habitat of salt marsh plants and marine life.