PROJECTION OF PHYTOPLANKTON BIOMAS IN WATER RESOURCES RESERVOIRS UNDER FUTURE ENVIRONMENTAL CHANGES

Abstract

 Future projection and assessment of water quality changes of water resources reservoirs in Japan which will be possibly caused by climate change and watershed environmental change, such as population decrease, were conducted in this study. The projection method developed in this study was composed of three components: vertical 1-dimensional models of water temperature and water quality prediction in reservoirs and a statistical model of water quality loading from watershed. As a result from simulations, phytoplankton biomass in reservoirs will be more affected by potential decrease of nutrients loading from watershed with the decline of watershed population than atmospheric temperature rise. However, our analysis suggested that reservoirs located in northern part of Japan where current population density is lower than average might face the possibility of water quality deterioration around the end of this century.