Study Of Agricultural Non-point Source Pollution In The Representative Drainage Area Of Lake Taihu Watershed Base On GIS Technology

Agricultural non-point source pollution is a ubiquitous environmental problem nowadays, and it is the most important factor for water environmental deterioration and lake eutrophication in China It's very significant in both theory and realism to control agricultural non-point source pollution and protect our ecological environment for realizing the harmonized development of resource, environment and agriculture in China.In this paper, a representative drainage area of lake taihu's watershed is choosed as the region of study base on analyzing and summarizing of much literatures. The actuality of agricultural non-point source pollution is analyzed, existent problems of non-point source pollution is pointed out by survey, collect and tidy of basic data on the representative drainage area. The concentrations of nitrogen and phosphorus are mensurated and analyzed in the rainfall runoff of plain river-net area. The law and character of nitrogen and phosphorus loss are discussed in the rainfall of plain river-net area. The works provide basic data and enrich theory proof for 863 project "strengthened purified pre-dam technology and engineering in the plain river-net area." Moreover, the evidence is provided for the validating of AGNPS model.The basic databases and special plots of the representative drainage area are completed with Mapinfo, Arcview etc GIS software, and space parameters for AGNPS model are picked-up by GIS's analyse and tidy technology of the space data. the load of nitrogen and phosphorus loss and surface runoff are calculated by AGNPS model, and the indispensable data are provided for the design and run ofthe pre-dam systems engineering.A scenario of strengthened purified pre-dam is presented according to the law of non-point source pollution in the representative drainage and the basic principle and the development at home and abroad of non-point pollution controlled by the classical pred-am and BMPs. It is expected that the model and methods can provide scientific basis for the water resources administration and decisions of the lake taihu which has great practical significance.