A study on the flood control measures by existing DAMS in the kase river basin in consideration of global warming

Here we discuss flood control adaptation methods in the Kase River basin using the existing Hokuzan Dam and Kasegawa Dam. Currently, the Kasegawa Dam is a multipurpose structure with the roles of flood control and water utilization, while the Hokuzan Dam is used only for water utilization. We investigated using the water utilization capacity of the two dams for flood control by using a prior discharge regime. Future climate conditions in the Kase River basin were set using the Database for Policy-Decision Making for Future Climate Change (d4PDF). The d4PDF is a large ensemble database of simulation results created using global atmospheric models of future climate conditions under scenarios where the global average temperature will have increased by 2 °C and 4 °C since the Industrial Revolution. Future heavy rain events in the Kase River basin on the basis of d4PDF were extracted and used for a flood flow simulation that included the effects of the dams on the flood flow. Our computational results demonstrated that the storage capacity of the two dams is large enough to control flow discharge due to future heavy rains. Therefore, if prior discharges from the existing dams are fully utilized, flood control is possible in the Kase River basin even under future extreme precipitation.