Towards Sustainable Reservoir Management Under Future Climate: A Modelling Approach

Climate change is affecting inland waterbodies such as reservoirs worldwide by altering the hydrological processes such as rainfall amount and the surface water evaporation. These changes shape the reservoir water level and subsequently affect dam storage capacity and functioning and the overall lake ecosystem including pattern of aquatic plant occurrence. In this study, the application of numerical modelling was performed to improve understanding on the impact of climate change on lake hydrology and water level in Beris Reservoir, Kedah in Malaysia. By incorporating land use pattern, hydrology, dam characteristics and operations as the variable parameters, hydrologic-hydraulic model was constructed using the integrated catchment model (ICM) approach. Calibration was performed using reservoir water level and rainfall amount at 2 rainfall stations near the catchment over 6 months. Two future hydroclimate projection data at the lake catchment (6 km grid resolution) are used to simulate the climate change impacts on the reservoir. Based on the simulation, the water balance of Beris reservoir is very sensitive to rainfall changes and the river water release for downstream water intakes. Frequency of changes in water level between the two scenarios provided better understanding on the potential occurrence of aquatic plants requiring reservoir management. The findings show that the numerical model predicts well the different climate change impacts on lake basin hydrology and ecosystem.