Impact of Climate Change on Water Resources on Simineh Rud Basin and Its Inflows to Lake Urmia

Lake Urmia is faced with problematic drawdown trend in the recent years that climate change can exacerbate this phenomena. This research work applies HadCM3 climate change data (scenarios A2 and B2) for the period of 2010-39 to evaluate changes in temperature and rainfall of the basin. To downscale these data a new approach is used، which is a combination of SDSM model and TOPSIS approach. Furthermore، the climate change data was introduces to the Soil and Water Assessment Tools model (SWAT) that was calibrated using local data and information to evaluate future changes in the basin’s runoff. Of course at this stage، only the Simineh Rud subbasin as one of the basin’s main subbasin was investigated. The results showed that climate change will reduce monthly rainfalls up to 40% and increase the temperatures up to 2 °C. Also، the basin’s runoffs will face with reduction of about 25%. Consequently، the inflows to lake may decrease about 30%. In general، the results of this research work emphasize on more attentions to the problems of the lake that will be booster under climate change condition