牧尾ダムの水資源管理に対するダム堆砂および気候変動の長期的影響

Abstract

Makio dam in the Kiso River is a multipurpose dam which generates hydroelectric power and supplies water to Aichi Irrigation Project. Reservoir sedimentation increased in the Dam because of Nagano West Earthquake in 1984. It cost about 3 million yen to recover active storage capacity in 1996 by excavating deposited sediments. In the future, flow regime is going to change due to global warming which will have another impact on water resources management. In this study, we assessed multiple effects of the several reservoir sedimentation scenarios and future inflow changes calculated by GCM model and distributed hydrological model (Hydro-BEAM). Regarding hydroelectric power generation, annual total generation can be almost maintained by modifying seasonal dam operation rule. However, water supply to the Aichi Irrigation Project will be subject to severe damage mainly by the loss of active storage volume and additionally by future flow regime change.