Abstract:Water samples from different underlying surface conditions, including grassplot, top of building, road in campus and road outside campus, were collected from 27 rainfall events in Hefei City. SS, COD, TN and TP were analyzed and compared. The study illustrated the time-varying regularity, the first flush effect, and the even mean concentrations of rainfall runoff pollutants on different underlying surface conditions. Results showed that contamination concentrations were commonly higher at the initial stage, while decreased with prolonging of the rainfall time and gradually became stable at the later stage. TN loading was high in rainfall runoff under both different underlying surface conditions and natural rainfall, indicating that atmospheric wet deposition contributed a lot to the TN of rainfall runoff. Variation of SS, COD, TN and TP in the road runoff outside campus were wider in the period from October 2009 to March 2010 than those in the period from April to September 2010. EMCs in the rainfall runoff depended greatly on different underlying surface conditions.