Study on the Risk Pattern of Non-Point Source Pollution Using GIS Technology in the Dianchi Lake Watershed

Abstract

A rapid quantitative risk evaluation system of non-point source pollution (NPSP), based on comprehensive consideration of various factors such as topographic features, land use construction, annual mean precipitation, soil erosion characteristics and pollutant removal cost, was constructed using an Spatial Analysis Module of GIS on watershed scale. We investigated the risk pattern of NPSP in the Dianchi Lake Watershed using the rapid risk assessment system. The results indicated that NPSP risk pattern showed the arc or normal distribution trend in the Dianchi Lake Basin, namely the medium risk area of NPSP is the largest (about 1311 km2). Moreover, the spatial difference of high risk NPSP pattern is remarkable: the high risk region for NPSP was primarily in the 10 km range of the southern and eastern parts and the 5 km range of western part around the Dianchi Lake.