EVALUATION OF FLOOD CONTROL FUNCTION OF EXSISTING DAMS FOR CLIMATE CHANGE ADAPTATION

Abstract

 In recent years, floods on a scale larger than planned level have frequently occurred in Japan, which needs urgent actions to mitigate these impacts regarding future increasing impacts under climate change. In this study, we focused on the flood control function of existing dams. We examined the flood control function in major river basins nationwide, the effect of preliminary discharge, and the priority evaluation method for rationally upgrading the functions of existing dams. As a result, we tried to clarify a relative comparison of flood safety for each river basin using the total equivalent rainfall volume in the basin (= total flood control capacity of dams in the basin / total river basin area). Specifically, we clarified the differences such as the installation level of flood control dams and the possibility of participation in the flood control function of other reservoirs such as hydropower dams. In addition, we showed that there is a possibility to select high priority dams which should enhance flood control capacities by using the relationship between the comparative constant proposed in previous studies and the basin area control ratio of dams.