Flood Risk Map System in Medium and Small Basins in China

Because of the developed economy and frequently happening flood disasters in coastal medium and small basins in the southeastern China, it is very important to research flood prevention and reduction. And flood risk map contains comprehensive information such as area nature, socio-economy and flood calamity, so it can play an important reference role in flood prevention and reduction. In this paper taking the Yonjiang River basin in the southeastern China as an example, the flood risk map information system supported by GIS is developed, also the method and approach to swift drawing the flood risk map in river basin are explored by using the database of historical flood and socioeconomic database as well as combining the dynamic analysis of spatial information of watershed. This has offered conditions for the dynamic updating of flood risk map, raised the accuracy of flood risk map and provided strong support to the fast decision for flood prevention and reduction in medium and small basins.