CLASSIFICATION OF IRRIGATION RESERVOIRS BY FLOOD DAMAGE REDUCTION AND EVALUATION BY RIVER SYSTEMS AND PREFECTURES

Abstract

 This study aimed to classify irrigation reservoirs contributing to flood damage reduction and evaluate the effectiveness of classified irrigation reservoirs in flood damage reduction in classA river basins and classB river basins. To evaluate the maximum effect of damage reduction in inundation analysis, the situation was defined in which no water was stored in irrigation reservoirs. The damage reduction effect of all reservoirs in Kako (18.6%), Ashida (13.0%) and Matsuura (12.8%) river systems, and Kagawa (18.1%), Okayama (8.6%) and Hyogo (7.4%) prefectures, was high. For 56 river systems and 24 prefectures, flood control use of irrigation reservoirs that reduce damage to sub-watersheds is expected. On the other hand, for 41 river systems and 14 prefectures, flood control use of irrigation reservoirs that do not reduce damage to sub-watersheds is expected.