GIS-based Risk Assessment for Regional Flood Disaster

Based on the digital topographic map of 1/ 250000 scale, a primary assessment for flood risk in Hubei Province has been made by use of the strong function on space analysis and overlapping of GIS (Geographic Information System) platform. Firstly, through analysis and digitization, four raster coverages are obtained about the following factors that compose flood risk: precipitation, topography, water system (including rivers, lakes and reservoirs) and frequency of historical floods. Secondly, a map of assessment for flood risk in Hubei Province is made by overlapping these raster coverages of the four factors. Results show that, the flood risk is highest in Jianghan Plain and Xiangyang Plain, their risk classification value is 5; it is less high in the edge areas of the plain and low in hill areas, the risk classification value is 4; most part of the mountain areas in west, northeast and southeast of Hubei Province have relative lower flood risk of classification value 2; the high mountain area of Shenlongjia has lowest flood risk of classification value 1. The above result is agreed with the facts of flood disaster occurred in history.