长沙市望城区海绵城市地表径流控制率分析

Analysis of Surface Runoff Control Rate of Sponge Cities in Wangcheng District,Changsha City

由于年径流污染控制目标可通过SS指标来控制。通过分析望城区域的径流雨水的污染物浓度、组成成分、水质等几个指标之间的关系和水量的变化,判定了控制SS指标能否控制住雨水污染:通过对望城区天然雨水水质、道路径流雨水水质、建筑屋顶径流雨水水质、海绵城市改造后的下垫面雨水径流水质及污染物相关性分析,分析了采用不同海绵设施,对各污染物的消减能力。结果表明:透水铺装、下沉式绿地和生态滞留设施对雨水径流中的污染物削减率较高,绿色屋顶和植草沟的对污染物削减率低,和设置比例有关,不少海绵地块检测的径流SS值较高,可适当提高LID设施设置比例,消减雨水。通过数据分析,可进一步指导雨水径流控制设施的选择,以期使望城区能达到年径流总量和年径流污染控制目标。

The annual runoff pollution control target is controlled by SS index.Through analyzing the relationship between the pollutant concentration,composition and water quality of runoff rainwater in Wangcheng area and the change of water quantity,this paper determines whether the SS index can control the rainwater pollution.By analyzing the water quality of natural rainwater in Wangcheng District,the water quality of road runoff,the water quality of building roof runoff,the water quality of underlying surface runoff after sponge city reconstruction and the correlation analysis of pollutants,this paper analyzes the ability of using different sponge facilities to reduce all pollutants.Through analysis,it is found that permeable pavement,sunken green space and ecological retention facilities have a higher reduction rate of pollutants in rainwater runoff,while green roofs and grass ditches have a lower reduction rate of pollutants,which is related to the setting proportion.The detected runoff SS value of many sponge plots is higher,so the setting proportion of LID facilities can be appropriately increased to reduce rainwater.Through the data analysis,we can further guide the selection of rainwater runoff control facilities,in order to achieve the annual runoff total and annual runoff pollution control targets.