The Study Of Agricultural Non-point Sources Pollution Based On Swat Model In Taihang Hilly Regions

Water is the source of life and the necessary strategic resource for the development ofthe country and society. Water environment in China is very serious. With the high-speeddevelopment of human society, water pollution has become a global environmentalproblem. With the point source pollution basically got better controlled and governed;non-point source pollution had become the main threat to the water environment. Theagricultural non-point source pollution had become the important reason of waterenvironment deterioration and lake eutrophication. Therefore, controlling of agriculturalnon-point source pollution and protecting the ecological environment had importanttheoretical and realistic significance to realize coordinated development of our countryagriculture, resources and the environment. Through establishing the agricultural non-pointsource pollution simulation model to calculate the agricultural non-point source pollutionload and analyze its space-time distribution features is the most effective way to makeresearch on agricultural non-point source pollution.This paper took the basin of Tang river above Xidayang reservoir as the study area.On the basis of comprehensively stating the research progress on non-point sourcepollution at home and abroad, the SWAT model was used in the paper which the UnitedStates agriculture department agricultural research institute developed, with combining itwith digital elevation model and the GIS system, to simulate the agricultural non-pointsource pollution in the research area. The main contents included:(1) The watershed of Tang River above Xi dayang reservoir was selected as the studyarea. In aid of the GIS, VF, EXCEL software, the spatial database and attribute database inthe study area were established. The spatial database included digital elevation modelDEM, landuse map and soil type map. The attribute database included the meteorologicaldatabase of precipitation, temperature, wind speed ect.and the attribute database of landuse and soil.(2) The SWAT model applying to this study area was established. The initial SWAT model was set up in the first place. Because the SWAT model needed a lot of parameters inthe simulation process and the uncertainty of these parameters had very big influence onthe model simulation results, the sensitive parameters needed to be adjusted. The articlecalibrated and verified the model by using the measured data from2008to2009andfinally got a SWAT model with good applicability.(3) The practical application of agricultural non-point source pollution model—SWAT model. According to simulating the agricultural non-point source pollution outputload of the runoff, sediment and nitrogen in different hydrological years, from the twoangles of time and space, the rules of the output and distribution characteristics of theagricultural non-point source pollution were analysed in the study area. By simulating thenon-point source pollution output load with different fertilizing measures, it was indicatedin the paper that there is a positive correlation between fertilizing and agriculturalnon-point source pollution output load.(4) According to the mechanism of agricultural non-point source pollution and theoutput load of agricultural non-point source pollution in different conditions, this articleprovided targeted scientific and effective countermeasures for controlling agriculturalnon-point source pollution.