Application of SWMM in the Simulation of Non-Point Source Pollution Load in Urban Residential Area

This study was focused on the non-point source pollution loading in a typical urban residential area in Wenzhou City,Zhejiang Province.Based on the SWMM principle,parameters from the literature and field experiments were integrated,and a non-point source pollution calibration model was constructed.Four different rainfall scenarios were designed to analyze the pollution loads and the accumulation process of total suspended solids(TSS),chemical oxygen demand(CODCr),total nitrogen(TN) and total phosphorus(TP).The results showed that the simulated data matched the field-monitored data satisfactorily.The relative errors between the simulated and the true values of all the four parameters were less than 10%.Under the four rainfall conditions: 1) the highest concentrations of the pollutants were observed within 30-40 minutes;the heavier the rain,the earlier their highest concentrations appeared;2) higher-intensity rainfall caused more serious pollution to the receiving water bodies than the low-intensity rainfall did.