Abstract
This study discusses river water quality with extreme precipitation change. We tried to project the water quality change by climate change such as heavy rainfall and lengthening of no rain period, and analyzed the variation ratio of turbidity loadings such as biochemical oxygen demand and suspended solid in Japanese typical rivers according to return period of extreme precipitation. L-Q rating functions and organic pollutants sedimentation model were applied to evaluate water quality during heavy rainfall and during draught period, resepectively.
As results, we are able to point out high risk rivers, which have worse water quality after climate change in Japan. And the following detail results were obtained; 1) In the Ara and the Gouno rivers, turbidity loading increases remarkably with changing rainfall condition.2) The turbidity loading process was clarified by draught period.3) Turbidity loading increases from 200 to 300% in case of a heavy rainfall by climate change in Japan. 4) Turbidity loading increases about 110% in case of longer draught period caused by climate change.
