Research on Water Quality Characteristics of Urban Roof Runoff and Initial Runoff Amount

The Study on the water quality characteristics of urban roof runoff and initial runoff amount can provide the basis for effectively using urban rainfall and controlling non-point source pollution,and so on.The hydrological and water quality process of three rainfall events on urban roof was sampling and analyzing in 2010 in Xinxiang City,Henan Province.The result showed that: ①The runoff coefficient of urban roof was 0.92~0.98,the shape runoff curve was similar with the rainfall process,both of them fluctuate lightly.②The standard deviation rate of water quality indicator was in the order of SSCODDOpH,which is consistent with directivity of these indicators′ concentration variation.③Along with the duration of rainfall,the variation trend of main pollutant index SS,COD in runoff was similar and tends to a steady value.④The correlation between SS and COD was good in the runoff,but that between DO and these pollutants was bad.⑤The initial runoff amount of urban roof was equivalent to 1~3 mm rainfall or runoff in former 15~20 min.