Non-point Source Pollution Risk Assessment Based on Impervious Surface Coverage of Dianchi Lake Watershed

Abstract

Environment changes caused by rapid urbanization is the hot issue in recent studies towards urban ecological environment, and one feature of it is that impervious surfaces increase continuously. The earth vegetation parameter characterized by impervious surfaces index (ISA) becomes the popular standard of water environment effect during urbanization process. This paper extracts data from the information of impervious surfaces in Dianchi Lake, chooses sub-basins of Dianchi Lake basin and lakesides as the space evaluation unit of urban non-point source pollution around Dianchi Lake basin, calculates the impervious surfaces cover within the space evaluation unite, estimates the risk level of urban non-point source pollution in Dianchi basin on the basis of the threshold value of the impervious surfaces & water environment influence, analyzes the variation regularity of water environment sensitivity under multi-time and multi-space scale, and estimates the non-point source pollution effect of land expansion of urbanization in lake basins positionally, quantitatively and qualitatively, so to offer theory bases and decision-making tools to positive land-using model in lake basin areas rapid urbanization.