Pengxi River is the largest tributary in the northern bank of the Three Gorges Reservoir area, which there is a medium eutrophication, great population density, apparent topographic relief of upstream and downstream, rich rainfalls and wide farmland area, as well as a typical basin for studying non-point source pollution.
The poster establish a spatial and attribute databases,including hydrology, climate, topography, vegetation cover, land use, agricultural population, livestock and poultry farming, planting and fertilization management,parameters of precipitation, terrain, vegetation coverage and distance to the river channel in Pengxi River Basin, to identify the impact factors of non-point source pollution.
The impact factors of non-point source pollution includes elevation, river distance, rainfall erosivity, slope and land use type. The arable land (arid land and paddy field) was the crucial source of non-point source pollution in Pengxi River Basin, with the reason associated with excessive domestic pollution was the second pollution source, which was correlated with the lack of centralized collection and treatment facilities for waste and sewage. Slope was the critical factor affecting total nitrogen loss in Pengxi River Basin, and rainfall is the critical factor affecting total phosphorus loss.
According these impact factors of non-point source pollution, the poster puts forward four pollution control scheme,including reducing fertilization appropriately, returning arid land to grassland with slope larger than 25 degrees, establishing hedgerows near river channels and basin outlet to prevent nitrogen and phosphorus from exporting to the river, and establishing biogas digesters to collect and treat rural domestic wastes livestock and poultry manure.