Simulation Study On Agricultural Non-point Source Pollution Of Greenhouse Region In The Eastcoust Of Dianchi Basin

After years of management, Dianchi Lake Basin’s watershed point source pollutionhas been effectively controlled. However, the extent of eutrophication water has notlessened. The main reason is the non-point source pollution in the basin at the rainyseason with rainfall runoff into the lake, resulting in Dianchi water pollution. Todaynon-point source pollution of Dianchi nitrogen and phosphorus pollution load rate closeto half of the total rate of lake basin. In view of this situation, four-level sewagesystemwas built to protect Dianchi. This is the first large sewage interception basinimplementation construction in the domestic. One of the very important part of theDianchi sewage interception and the final barrier is Dianchi Sewage InterceptionChannel project. However, because lack of designing and manage meature, andvariation of non point source sewage water in the collectionprocess is not clear, it isdifficult to collect the maximum contaminant concentration sewage. Therefore,identification of agricultural non point source runoff and pollution load variation inrainfall process of Sewage Interception Channel Project of DianchiLake plays animportant role.This study aimed at the sewage interception channel around Dianchi valley projectissue, discussed water quality and quantity dynamic variation of the agriculturalnon-point source pollution in the demonstration area between Maliao River andLuolong River. This study selected typical agricultural areas--vegetable and flowergreenhouse region as the research object.Monitoring and simulating agricultural non-point source runoff and pollution load variation. The main conclusions of the study are:①Nitrogen and phosphorus is the main pollution components of greenhouse’sagricultural non-point source pollutant of east coast in Dianchi basin. Nitrogen andphosphorus mainly consist of the dissolved fractions. Dissolved nitrogen accounted formore than75%of total nitrogen. Dissolved phosphorus accounted for about60%oftotal phosphorus.②The flower shed group’s ammonia nitrogen is the main form of total nitrogen inthe early stage of rainfall, and then gradually reduced following the runoff collectiontime. The ammonia nitrogen content in vegetable greenhouses in the early stage ofrainfall is quite low, less than10%of total nitrogen, but then increased sharplyfollowing runoff process. It decreased after the peak concentration. ③A non-point pollution model of studied area was built based on the SWMMmodel. Using The Chicago process line synthesis rainfall data, runoff flow rate andpollutant concentration lines of vegitable greenhouse and flower greenhouse wassimulatied under different rainfall circumstances.