Regional Hydrologic Impact Assessment of Climate Change on Reservoir Inflows under the CMIP5 Climate Projections

This study is designed to quantify the effects of climate change on hydrologic flow regimes in the Gediz Basin in Western Turkey during the 21st century. As the regional atmospheric model, the weather research and forecasting (WRF) Model was employed to dynamically downscale the outputs of two global climate models, HadGEM2-ES and GFDL-ESM2M, to a 6-km grid resolution under two IPCC representative concentration pathway scenarios (RCP4.5 and RCP8.5). The downscaled atmospheric data were then used to drive the watershed environmental hydrology (WEHY) model, a fully physically-based hydrologic model, over the Gediz Basin in order to obtain the total amount of water inflows into the basin's major reservoir. Historical period inflows (1985-2012) were compared to the future projections of reservoir inflows (2017-2100). Trends in annual inflow projections were also analyzed. The results suggest an increase in the amount of future projected inflows during the 21st century.