Research On The Characteristics And Variation Law Of Nonpoint Source Pollution In Reservoir In Branch River Of Three Gorges Reservoir Area

According to statistics, the three gorges reservoir area of the contribution rate ofagricultural non-point source pollution by more than50%. It caused a serious threat todrinking water safety and the ecological environment.Watershed non-point sourcepollution is affected by many factors, mechanism, wide distribution, complex strongrandomicity, is hard to estimate the latent is strong, and difficult to focus at the end oftreatment, the comprehensive evaluation and management is a complicated systemengineering, of the three gorges reservoir area nitrogen, phosphorus and the typicalsmall reservoir basin pesticide of migration and space-time distribution of agriculturalnon-point source pollution research, for the three gorges reservoir area of social,economic and environmental sustainable development, promoting the ecologicalharmony and safeguard the reservoir water environment safety is of importanttheoretical significance and practical value.Based on the three gorges reservoir area ofthe Yangtze river level tributaries flower river upstream from the south peng reservoirbasin as an example, based on the conceptual hydrological model (NAM) model,simulation with total nitrogen, total phosphorus non-point source pollutants migrationand the time-space distribution law of hydrological processes, the basin to analysis thecause of nitrogen, phosphorus non-point source pollution, and puts forward thecountermeasures.The following results:(1) The nitrogen and phosphorus discharge of pollutants, the non-point sourcepollution accounts for a large proportion.(2) In terms of nonpoint source pollution load composition, the main non-pointpollution source in the study area mainly comes from the agricultural production causedby the large amount of dissolved nutrients.(3) The generation of nonpoint source pollution load and the basin rainfall runoffprocess has a very good response, there are significant seasonal differences.Floodseason for the generation of nonpoint source pollution have made outstandingcontributions,6to8months accounted for36.60%of annual rainfall, runoff accountedfor32.39%of total nitrogen and total phosphorus content respectively accounted for67.15%and85.92%of the total.(4) Under the action of runoff of livestock and poultry breeding is the main sourceof pollution, accounting for91.70%of the total (TN) and34.33%(TP).