基于EFDC模型的天镜湖水动力优化调控方案研究

Control and Optimization Scheme of Tianjing Lake Hydrodynamics Based on EFDC Model

太仓市天镜湖以长江水为水源,补水量只能维持蒸发渗透水量,湖水基本不动,水体极易处于高度富营养化状态。针对该湖现有问题,利用环境流体力学模型(EFDC模型)建立了天镜湖的三维非稳态水量、水龄、污染物颗粒追踪数学模型,对天镜湖水动力优化调控方案进行了模拟(模拟内容包括水位、流速和水龄)。模拟结果表明,通过浏河闸开启向天镜湖引水能够在一定程度上加强湖入口和中心区域的水体流动性能,且浏河闸开启的时间越长效果越好,但引水对天镜湖内部(远离入口处)区域的水动力无明显的改善作用;在西南风条件下,开启浏河闸引水对湖区的水动力改善效果最好;在现状条件下,湖区中存在多处水体交换差的区域(集中在湖周边和远离入口的地方),可能成为天镜湖潜在的水体富营养化高发区。

The headwaters of Tianjing lake,located in Taicang,is Yangtze river.The capacity of supplementary water can only maintain the evaporation and permeation of water,and the lake water basically does not flow.So,the lake is highly vulnerable to be at high eutrophication level.Aiming at the current situation of the lake,this paper established a mathematical model by using EFDC model to trace three-dimensional unsteady flow,the age of water and particulate contaminants and simulate the scheme of control and optimization hydrodynamics,including water level,flow rate and water age.The simulation results show that by opening the Liuhe floodgate to divert water to Tianjing lake,to some extent,it can enhance the flow property of the water in the entrance of the lake and the central region;the longer the opening time of Liuhe floodgates lasts,the better the effect is.However,the hydrodynamics of water inside（far away from the entrance）has no significant improvement;when the wind blows from the southwest,the hydrodynamics can be improved to the utmost by opening the Liuhe floodgate;under the existing circumstances,the regions（concentrated in the area away from the entrance and the edge of the lake）with poor water exchange could be with a potential high incidence of eutrophication.