Modelling of Non-point Source TSS Pollution Load during Rainfall Events in Panxi River Basin in Chongqing

Urban non-point source pollution is becoming more and more serious due to the rapid urbanization. Consequently,estimation of the non-point source pollution load and its source analysis have attracted widespread attention in the treatment of the non-point source pollution. The pollution load model for the two rainfalls in Panxi river basin in Chongqing was developed. The TSS concentrations during the two rainfalls were estimated. The TSS loads of each sub-catchment were calculated. The results showed that the built model could well simulate the production and collection process of the non-point source pollution,especially with higher simulation accuracy of the first flush process during the initial rainfall. During the two rainfall events,there were obvious first flush effects. In the first 30% of the runoff,TSS during the two rainfalls could reach 90% and 75% respectively. The removal rate of TSS per unit area could better describe the pollution levels of each sub-catchment,and then provide the scientific basis for watershed non-point source pollution control.