Abstract
This research paper aims to estimate the eutrophication of dam reservoirs for drinking water caused by future climate change, and to evaluate the impact against water utilities and the effectiveness of adaptation measures in a national scale. Based on two emissions scenarios, average annual Chl-α concentrations of surface layer water at present and in the future were estimated in 37 objective dam reservoirs, and affected populations by the change in water quality were calculated based on the water intake amount of 54 water utilities that take water from the 37 dam reservoirs in each region. It was estimated that a Chl-α concentration tends to increase till the 2100s. Although the ratio of affected population among supplied population has increased till the 2100s, the affected population will reach a peak in the 2050s and will decrease after the 2050s due to natural population decline in Japan. The research presented that, as an adaptation measure, an introduction of circulative aeration facilities in dam reservoirs can decrease the affected population and can reduce the cost of advanced water treatment system construction.
