Water Quality Research of Zhongxian in the Three Gorges Reservoir Before and After Impoundment

Through monitoring the water quality of Zhongxian area of Three Gorges Reservoir from 2001 to 2007,the change of water quality before and after impoundment was analyzed.The results showed that the water quality of Zhongxian area of Three Gorges Reservoir was quite stable before and after impoundment,the basic categories of water had not been changed,the surface water was at gradeⅢ,characteristics of water pollution was also not changed before and after impoundment and the major pollutants were COD,BOD5,CODMn,TN and TP,the level of pollution and proportion in the whole pollution were both declined year by year.In each stage of impoundment,the hydrological changes were the main factors.The impoundment,suspended solids and water quality had some correlation.The impoundment reduced water suspended solids and improved water quality.