Non-point Pollutant Source Analysis And Its Numerical Simulation Study In Chongqing Three Gorges Reservoir Region

Non-point source pollution (NPS) occurred generally over an intermittent period of time from diverse sporadically sources, and is often correlated with climatic events. Pollutant source of the Three Gorges Reservoir Region mainly is point source pollution and non-point source pollution, whose the latter occupied 77.85% of the total loadings. On the basis of data in 2000, this paper evaluated and analysed the non-point pollution source with the method of equivalent pollution loadings and cluster analysis in Chongqing Three Gorges Reservoir Region. The total pollution loadings of non-point source in Chongqing Three Gorges Reservoir Region were simulated and estimated by using Revised Universal Soil Loss Equation—RUSLE and The Nutrient Loading Model—NLM, whose results were analysed respectively. All will be stated next.On the basis of data in 2000 and the method of equivalent pollution loads, this paper evaluated the non-point pollution source, including rural domestic waste, solid waste, fertilizer runoff, pesticide runoff, poultry and livestock farm, soil erosion, surface flow of city and so on in Chongqing Three Gorges Reservoir Region. The 40 administrative districts of non-point source pollution in Chongqing Three Gorges Reservoir Region were divided into 8 areas with the method of cluster analysis and equivalent pollution loads. The main nutrients of non-point source pollution were total phosphorus, total nitrogen, ammonia nitrogen, chemical oxygen consumption etc, in which loadings of total phosphorus and total nitrogen had 96.4%. The main pollution sources were fertilizer run off, soil erosion, poultry, livestock farm, rural domestic waste, pesticide runoff, solid waste and surface flow of city etc, in which loadings from fertilizer run off, soil erosion, poultry and livestock farm had 95.2%. The sum of mean values of evaluation indexes in each area according to cluster analysis increased by degree fromⅠt oⅧ, which account for the differences of non-point source pollution in each area of Chongqing Three Gorges Reservoir Region. In addition, non-point source pollution in each area had respective characteristics, which provided scientific technique for control non-point pollution source. In conclusion, on the basis of data in 2000, combined together the method of equivalent pollution loadings and cluster analysis, we analysed the main pollution matters and pollution sources from non-point source pollution, and realized the properties of non-point pollution in each area of Chongqing Three Gorges Reservoir Region.