Loss of Non-Point Source Pollutants from Xikeng Reservoir Small Watershed in Shenzhen

Nitrogen and phosphorus,coming mainly from non-point sources(NPS),are major nutrients to cause eutrophication to degrade water quality of Xikeng reservoir,one of the important drinking water sources in Shenzhen. Based on the land use and geographical condition,the research area is classified into different types of non-point source areas as follows: agricultural land,forestland,bared land and village.Soil erosion mount of each plot are calculated by using USLE equation and pollutants of runoff(TSS,TN,TP,NH+4-N,BOD,COD) are analyzed by field tests.The results show : the loss amount of soil from forest land and agricultural land are relatively high;TP,TN concentrations of diffuse samples from villages and farms units are higher.These areas should be treated as critical areas of non-point source pollution.