Abstract:

In this paper,a part of the drainage area in Xinhepu Community in Guangzhou city was selected as the research region and was divided into three typical types of land surfaces,namely the residential area,the road and the grass. Then,the water quality for several rainfall events on the three types of land surfaces was monitored in terms of chemical oxygen demand ( COD) ,biological oxygen demand ( BOD₅ ) as well as the concentrations of total suspended solids ( TSS) ,total nitrogen ( TN) ,total phosphorus ( TP) and ammoniacal nitrogeon. Moreover,the relationship between TSS and COD was discussed,and the space-time change law of the pollutants as well as the first flush effect of the runoff was analyzed. Finally,a non-point source pollution model of rainfall runoff was established based on the storm water management model ( SWMM) and the corresponding model parameters were determined according to the observation data. The results show that ( 1) there is no obvious relationship between TSS and COD; ( 2) the first flush effect is obvious in both the residential area and the road,but is not obvious in the grass; and ( 3) the proposed model is of high accuracy and it helps to reasonably simulate the non-point source pollution load varying with the rainfall intensity,the rainfall type and the recurrence period,and provides a reference for the non-point source pollution control of urban runoff.

Key words: Guangzhou city, rainfall runoff, urban non-point source pollution, water quality monitoring, storm water management model, pollution load