Abstract
A fundamental study on impact assessment of climate change on operation of reservoir systems and river discharges in Japanese river basins were conducted as a fundamental study in order to develop a method to operate reservoirs more effectively under the expected future climate condition. Current climate data (1979-2003) and future climate data (2075-2099) projected by MRI-AGCM3.2S, a high resolution AGCM developed by Meteorological Research Institute, were used as meteorological input. River discharges in both climates were respectively estimated from climate data by use of Hydro-BEAM, a cell concentrate type hydrological model, integrating operation of reservoirs for water supply and water intake in the target river basins. The assessment was conducted in the Yoshino River basin where droughts often occur, and the Mogami River basin where snow melting water contributes to river discharge significantly. The results suggested that the potential changes in river discharge that may increase a risk of drought in the future. The assessment also showed that the a shift in the snow melting period may not impact water use operation of multi-purpose reservoirs such as the Shirakawa Reservoir that has a seasonal regulation to lower the water use capacity in order to enlarge flood control capacity after the drawdown period.
