Study On Rainwater Runoff Pollution Control In Yixing New Urban District And Beijing Liangshui River Basin

With the acceleration of urbanization in China,the impervious area of urban built-up area is increasing rapidly,which leads to the increasingly serious pollution of urban runoff.The paper studied the urban non-point source pollution in the important cities of Yixing new urban district in Taihu Lake basin and Liangshui river basin in Beijing.Based on the analysis of the characteristics of the non-point source pollution,we proposed control schemes for the non-point source pollution in these two regions.Through field survey and literature analyses,this paper tried to clarify the characteristics of the surface pollution caused by runoff in the New Urban District of Yixing,and confirm that the main characteristics of local source pollution are high concentration of COD and SS in the initial rainwater,the runoff pollution concentration varies greatly between different underlying surfaces.Thus,a non-point source pollution control scheme for this region was constructed,including the rain source reduction control system based on the LID(low impact development)measures,and the SWMM rainstorm and flood control model was employed to simulate the operating condition of the system to verify the efficiency of the system on the reduction of total amount of rainwater runoff,the peak flow rate of rainwater and the runoff pollutants,achieved 70%reduction in rainfall pollution in the region and 40%reduction in SS.At the same time,research also have been conducted on the Beijing Liangshui river Basin.Field survey and literature analysis showed that the water quality of the Liangshui River Basin exceeds the V standard of surface water.The main pollutants include COD,BOD5,SS,TN and TP,and the serious pollution is resulted from the overflow pollution from the combined drainage outlet and the surface pollution caused by the runoff in the basin.Based on this,the control scheme of nonpoint source pollution for the Dayangfanggou tributary,one of the branches of the Liangshuihe River basin was established.The system includes 3 main pipe for interception and the scheme of using LID technical measures to control the surface source pollution of rainfall runoff,as well as the employing of the SWMM rainstorm and flood control model to simulate the reduction effect of source pollution control measures under different rainstorm recurrence periods,achieved 70%reduction in rainfall pollution in the region and 40%reduction in SS.