南京城区两类典型屋面降雨径流的特征

Characteristics of Two Types of Typical Roof Rainfall Runoff in Urban Areas of Nanjing

该文对2014年南京市两场降雨径流的水文水质进行采样分析。研究不同屋面径流水质的特征,分析屋面径流初期冲刷效应,探究径流污染物间的相关关系。结果表明,屋面径流COD污染严重;各项水质指标离散系数大小呈现:SS>COD>NH3N>pH,其中SS、COD、NH3-N随降雨历时变化趋势基本一致;平顶水泥屋面的COD和NH3N污染负荷高于坡顶瓦屋面,SS污染负荷则低于坡顶瓦屋面;坡顶瓦屋面初始冲刷效应明显,平顶水泥屋面则无初始冲刷现象;SS和COD相关关系很好,NH3N和SS、COD相关关系较差。

Taking 2 rainfalls of Nanjing in 2014 as an example, the author analyzed the roof runoff water quality. Characteristics of runoff in different roof, first flush of roof runoff and correlations between pollutants of roof runoff were studied in the paper. The results show that the pollution extent of COD is serious. Coefficient of dispersion of water quality index show that SS 〉 COD 〉 NH3- N 〉 pH, and SS, COD, NH3- N are basically the same trend with the rainfall duration. Besides, pollution load of COD and NH3- N which in fiat cement roof are higher than in the top tile roof,but the pollution load of SS is lower than which in the top tile roof. First flush effect of the slope tile roof runoff is obvious, but there is no first flush effect in the fiat cement roof runoff. SS and COD have a good correlation, but correlations between NH3- N and SS, COD are poor.