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结合通用土壤流失方程(USLE)和USEPA开发的PLOAD方程,建立非点源污染计算模型,采用GIS技术及野外实验确定模型中各个因子,并将该模型用于长沙市的非点源氮、磷污染负荷的计算。研究结果表明:长沙市地区非点源氮、磷污染负荷分别为9.9kghm-2a-1,1.49kghm-2a-1,其中氮污染主要以溶解态氮的形式存在,与降雨过程中产生的地表径流密切相关;污染来源最大的区域是城市用地区域,该区域的下垫面不透水率大,降雨过程中产生地表径流大;磷污染主要以吸附态磷的形式存在,来源较大的区域主要为坡度大、易发生水土流失的区域。
Combined with the general soil loss equation (USLE) and the PLOAD equation developed by USEPA, a non-point source pollution calculation model was established. The GIS technology and field experiments were used to determine the various factors in the model. The model was applied to non-point source nitrogen and phosphorus Pollution load calculation. The results showed that the non-point nitrogen and phosphorus pollution loads in Changsha were 9.9kghm-2a-1 and 1.49kghm-2a-1, respectively. The nitrogen pollution was mainly in the form of dissolved nitrogen, The most polluted area is the urban land area, the underlying surface of the area has high water impermeability and large surface runoff during the rainfall. Phosphorus pollution mainly exists in the form of adsorbed phosphorus, and the area with the largest source is mainly For the gradient, prone to soil erosion area.