Application Of SWAT Model Based On GIS For The Simulation Of Agricultural Non-point Source Pollution

One of the major reasons,which is agricultural non-point source pollution,causes water environment pollution in China,and this kind of pollution is intermittent,random,strongly uncertain and complex process.It is really difficult to estimate its value of load.It is the effective method to control and research agricultural non-point source pollution,through the combination of digital model of agricultural non-point source pollution,GIS and RS. This method is simulated by the computers,and analyzes the regulation of space-time changing.This thesis completely demonstrates the development of agricultural non-point source pollution in domestic and overseas.Analyzing SWAT model which is based on GIS software with ArcSWAT technology principle,and doing research in the Nette drainage area to get the simulation of watershed hydrological and the distributed simulation methods of nutrition immigrating.The main purpose is to research the distributed simulation methods of nutrition immigrating and verify regional applicability.â– Analyzing the SWAT model's principle,technology and method.The characters of model when it works.Transforming the soil applying data,soil data and other relative data with the standard ways.According to the character of data's construction needed by the model working,,establishing one set of basic agricultural non-point source pollution information database.With DEM, extracting watershed network and watershed boundary,dividing the sub watershed rivers,and then making HYUs divided.Finally,discrete and parameterize the space of watershed.â– Collecting relative monitoring data about hydrologic and water quality from the basin outlet.Selecting the true data from 2001-2003 monitoring,and comparing with watershed model and simulation of nitrogen and phosphorus.Analyzing the parameter in the sensitive methods.Via this way,to rectify the simulation of nitrogen and phosphorus,at least,getting one set of relative appropriate model parameters.â– Analyzed the results of model,space and application of model,the character of lacking nitrogen and phosphorus is from North to South in the dimension of space. The main reason is that the nitrogen and phosphorus is gathered into middle area, and South is farm land and farmer resident,and the North is less forest areas. Compared with hydrologic and water quality from the basin outlet monitored from 1996 to 2006,the model simulation gets the more accuracy.The load of nitrate-N, mineral-P and N-P basically reflects the losing status in that watershed,however, there are several months existing great errors.From the point of this view,SWAT model can predict the watershed producing water and sands very well,but there also be some errors existing in certain climate situation controlling geography process.To the immigrating nitrogen and phosphorus,we have to further research its application.