基于GIS的乌江流域地表径流模拟研究

Simulation of Surface Runoff of Wujiang Watershed Based on GIS

基于GIS平台，建立了数字乌江流域。在此基础上，选择5个典型子流域，利用流域1956-2000年的降雨和水文资料及流域2000年土地利用数据，分别计算5个子流域的年均降雨量、年均地表径流量和土地利用百分比；用多元回归分析工具建立流域年均地表径流量与年均降雨量和土地利用百分比之间的关系式，得到不同土地利用方式下的降雨径流模型；通过实测资料对模型进行验证的结果表明，模型模拟精度较高，相对误差在7％以内。

Non-point source pollutants are mainly carried over land and into stream networks by surface runoff, and how to simulate surface runoff is the key to determine the loads of non-point source pollutants. The volume of surface runoff is chiefly controlled by climates, topographical characteristics and types of land use of the watershed. Five subwatersheds that can represent the whole watershed are chosen and their average annual precipitation, average annual surface runoff and percent land use are calculated respectively in digital Wujiang watershed based on climatic and hydrological data from 1956 to 2000 and land use data of 2000. The surface runoff is assumed to be a function of precipitation and land use and the regression tool is used to determine the relationship between surface runoff, precipitation and percent land use. So the rainfall-runoff models in all kinds of land use types are built. The result shows that the relative errors are all below 7% and the accuracy of the models is high.