城市透水性下垫面降雨径流污染的影响因素研究

目的]探究城市透水性下垫面降雨径流污染的影响因素。方法]从降雨径流产汇流特性和污染物冲刷规律角度,在实验室条件下对3种透水性下垫面(草地、透水砖、压实裸地)的降雨径流污染进行正交试验。结果]草地、透水砖及压实裸地的次降雨径流系数差异较大,分别为0.28~0.43、0.35~0.55、0.72~0.74,地表的溶解性污染物冲刷进入径流水体中的比例较高,冲刷率可达50.00%~88.00%。坡度和降雨强度极大地影响产流过程,是影响产汇流时间、径流水量和电导率的重要因素;流量峰值产生时间、电导率峰值产生时间、退水时间、退水量和径流系数主要取决于下垫面性质;降雨动能的影响大于下垫面的入渗量,是影响溶解性污染物冲刷效率的最主要因素。结论]该研究可为海绵城市建设提供科学依据。

Study on the Influencing Factors of Rain-Runoff Pollution of Urban Permeable Underlying Surfaces

Objective]To study the influencing factors of rain-runoff pollution of urban permeable underlying surfaces.Method]Based on the characteristics of rainfall runoff and pollutant scouring rule, orthogonal experiments were conducted to study the rainfall runoff pollution of three permeable underlying surface (grasslands, permeable bricks, bare land) under laboratory conditions.Result]The results showed that the runoff coefficients of grassland, permeable brick and bare land were significantly different, which were 0.28-0.43, 0.35-0.55 and 0.72-0.74, respectively.The proportion of dissolved pollutants into runoff water was high, and the scouring rate can reach 50%-88%.The slope of the underlying surface and rainfall intensity were the most important factors affecting the runoff process, which influencing the runoff yield, runoff volume and conductivity.The time of peak runoff, peak conductivity and water withdrawal, the amount of water withdrawal and the coefficient of runoff mainly depend on the underlying surface properties.The influence of rainfall kinetic energy was larger than that of underlying surface infiltration, which was the most important factor affecting the scouring efficiency of dissolved pollutants.Conclusion]The study can provide scientific basis for the construction of the city.