Investigation the effects of climate change on water resources of Ilam Dam Watershed

Climate change and global warming is one of the most important issues in the world that is discussed in public and professional meetings. Long term climate change forecasting has an important role on water resources planning and management, due to fragile climate of our country. The present study aimed to investigate the effects of climate change on discharge changes in Golgol Watershed as one of the Ilam dam sub-watersheds. In this research, first, temperature, precipitation and potential evapotranspiration data were downscaled and then, hydrological condition of the watershed is simulated using SWAT hydrological model. Next, the results of downscaled HadCM3 data under two scenarios of A2 and B2 were downscaled using SDSM and in the next step stream flow of three period including 2010-2039 (2020s), 2040-2069 (2050s), 2070-2099 (2080s) and base period of 1990-1961 (Baseline), simulated using SWAT model. Finally, the effects of climate change assessed until the end of the century. The results indicated that annual discharge will decrease for 2020s, 2050s and 2080s under A2 scenario by 6.3, 16.9 and 24.1percent, and will decrease under B2 scenario by 10.9, 8.8 and 13.2 percent, respectively. Resualts demonstrated that climate change as one of the negative phenomena that affects on the amount of water in Ilam Dam should be considered by managers and planners.