生态补水对城南河水质水量改善效果研究

Study on the effect of ecological water supplement on water quality and quantity in Chengnan River

为改善城市河道枯水期流量小、水位低、水动力不足、水质污染严重等情况,以南京市城南河为例,进行枯水期生态补水方案效果研究。通过综合考虑枯水期上下游及干支流水质状况,同时结合补水水量及补水方式(包括间断补水和持续补水)的差异性设置补水方案。论文建立了研究区域MIKE11水量水质耦合模型,模拟分析不同补水方案下污染物COD、NH3-N、TP削减率及流速分布变化,进而得出不同生态补水方案效果。结果表明:随着补水水量的增长,污染物浓度削减率的增幅先快后慢;间断补水方案优于持续补水方案;生态补水对污染物浓度的削减效果显著,对于水质较好和曲折连绵的河段的改善不明显;生态补水对流速分布的改善效果明显,但受到河道内建筑物的影响,需要综合考虑确定补水点。

In order to improve the low discharge,low water level,insufficient hydrodynamic force and serious water pollution in urban rivers during the dry season,the effect of ecological water supplement schemes in the Chengnan River of Nanjing City was studied.By comprehensively considering the water quality conditions of the upstream and downstream,and the tributaries in the dry season,the water supplement scheme was set up according to the difference of water supplement quantity and mode(including intermittent water supplement and continuous water supplement).The coupling model of water quantity and quality of MIKE11 was established in the study area.The changes of pollutant COD,NH3-N,TP reduction rate and velocity distribution under different water supplement schemes were simulated and analyzed.The effect of different ecological water supplement schemes was obtained.The results showed that with the increase of water supplement,the concentration of pollutants decrease rate was fast and then slow.The intermittent water supplement scheme was better than the continuous water supplement scheme.Ecological water supplement had a significant effect on reducing pollutant concentration,but the improvement of the water quality in the long and tortuous river was not obvious.The effect of ecological water supplement on the improvement of the velocity distribution was obvious,but due to the influence the river structure,careful consideration needed to be made to determine the water supplement point.