Abstract
In Japan, the water utilization in urban areas is controlled separately by managers of water supply systems, sewer systems and river systems. It is a reason why a total countermeasure is not adopted for various risks. In this paper, these managers are considered in one water circulation system, and a hierarchical water circulation model is proposed to deal with how to mitigate the risks of the earthquake disaster, the environmental disaster and the drought disaster for water supply in urban areas. The model is consists of a river layer, a water supply layer, a water user layer and a sewerage layer, and decision makers of each layers are considered in it. The model is constructed by GIS. The application of this model is expected to provide necessary information to the mitigation plan of the disaster.
