城市下垫面截流降污效应模拟研究

Simulation study on rainfall infiltration and pollution-reducing effect of underlying surfaces in urban area

城市下垫面的改变影响了城市原本的水文状态,成为城市内涝和城市地表径流及地下水污染的主要原因之一.采用不同比例粘土与砂混合模拟城市下垫面作为研究对象,通过某市工业区小时最大雨量进行模拟经流,研究不同渗透性能下垫面的截流降污效应.结果显示：模块的含砂量与其蓄渗效果呈正相关,单个模块的蓄渗率为1.43%~41.18%;对模块进行组合时,增加透水模块的比例可以提高蓄渗能力,当透水下垫面与不透水下垫面比例为3∶1时,蓄渗率为40.22%,比例为4∶1时,蓄渗率达到50%以上.总体来说,下垫面的去除率与其蓄渗率呈正相关,渗透型下垫面对SS去除效果明显,对COD、NH4-N、TP、Pb等有一定的去除效果.

The change of urban underlying surface affects the original hydrological condition of a city, which has become one of the main reasons of urban waterlogging, urban runoff pollution and groundwater pollution. Taking the simulated urban underlying surface made by mixed clay and sand with different proportions as the research object, this paper studies the rainwater pollution reduction and closure effect of the underlying surface with different permeability through the maximum rainfall per hour of the city industrial park. The results show that sand content storage of module and its storage and infiltration efficiency are positively correlated; the storage and infiltration rate of a single module is 1.43 %-41.18 %. When the module is combined, increasing the proportion of the water-permeable module can improve the storage and infiltration capacity .When the ratio of permeable and impermeable underlying surface is 3：1, the storage and infiltration rate is about 40.22 %. When the ratio is 4：1, the rate is above 50 %. In general, the underlying surface removal rate of pollutants is positively correlated with its storage and infiltration rate. The SS removal effect of permeable underlying surface is obvious and has some certain removal effect for COD, NH4-N, Pb and TP.