Effects of Climate Change on the Movement of Turbidity Flow in a Stratified Reservoir

In this study, we investigated the effects of climate change on the movement of the turbidity flow in a stratified reservoir. Reservoir turbidity is primarily caused by the concentration of suspended solids in a watershed. Under the effects of climate change, which increases the frequency and intensity of extreme weather events in the Asian monsoon area, turbidity can be considered to be an essential water quality variable in a reservoir that supplies drinking water. We adopted a two-dimensional hydrodynamic water quality model coupled to a watershed model and used a future climate scenario applied to the Yongdam Reservoir in South Korea. To account for the uncertainty of climate change scenarios and the extent of the variation of both temperature and precipitation, three cases each from the 2050’s and 2090’s were selected for simulation. The simulations predicted that the significance of the summer stratification would produce a vertical circulation lower than 8 m in the warming reservoir of the 2090 scenario in comparison to 15 m in the 2050 scenario. The limited vertical circulation caused the density plume to spread within a depth of 8 m of the reservoir, isolating the upper water with high suspended solid concentrations from the hypolimnetic water. The results of this study provide the optimum horizontal and vertical location of the intake aqueducts to obtain drinking water with low turbidity during extremely heavy rainfall.