大型城市内湖水动力水质数值模拟及环境治理方案效果评估

Numerical Simulation of Dynamic Water Quality of Inner Lakes in Large Cities and Evaluation of the Effect of Environmental Treatment Plans

以大型城市内湖汤逊湖为例,通过建立二维水动力水质模型,对近远期、不同控源截污、不同生态补水等多情景下汤逊湖的流场及COD、NH-N、TP、TN等污染物浓度空间分布进行模拟,探究控源截污和生态补水等措施对水动力条件及水质改善效果的影响。结果表明:污染源削减措施配合工程调水引流,能最大限度改善水质状况,补水流量可随污染源削减率提高而减小。近期各污染物指标削减率达到50.96%~77.62%,生态补水40 m^(3)/s,远期各污染物指标削减率提高至67.77%~78.61%,生态补水10 m^(3)/s,可以实现汤逊湖水质长期稳定达标。

Taking Tangxun lake, an inner lake in a large city as an example, by establishing a two-dimensional hydrodynamic water quality model, the flow field of Tangxun lake and the spatial distribution of COD, NH3-N, TP, TN and other pollutant concentrations are simulated under multiple scenarios, such as short-term and long-term, different source control and pollution interception, and different ecological water replenishment. The effects of measures such as source control and pollution interception and ecological water replenishment on hydrodynamic conditions and water quality improvement are explored. The results show that the pollution source reduction measures combined with the project water diversion and drainage can improve the water quality to the greatest extent, and the water replenishment flow can decrease with the increase of the pollution source reduction rate. In the near future, the reduction rate of each pollutant index reaches 50.96%~77.62%,and the ecological water replenishment is 40 m^(3)/s. In the long term, the reduction rate of each pollutant index increases to 67.77%~78.61%, and the ecological water replenishment is 10 m^(3)/s, which can achieve the long-term stability of the water quality standard of Tangxun lake.