Simulation of Climate Change Effect on The Runoff of Shazand Basin Applying WetSpa Distributional Model

The appearance of climate change and its effect on different parts of water cycle make it essential to be aware of the status of water resources to correctly manage water resources. In this study, at first, the WetSpa model was implemented and calibrated for the basin, and then the output of the CanESM model was entered in to the downscaling model of SDSM under three scenarios and the meteorological data of coming years was received and finally the change of the runoff of the studied basin was determined by the use of hydrologic model for the coming years. The results of CanESM2 confirmed that at the most stations the temperature values would increase and the amount of precipitation would decrease, RCP 8.5 scenario shows more changes. The results of runoff simulation under climate change scenarios indicate a decrease in runoff amount and this amount was 5.53%, 13.89% and 25.1% for RCP 2.6, RCP 4.5 and RCP 8.5 scenarios. The high compatibility of the computational and the observational hydrographs, especially for the high inflows which were 92% and 86% for calibration and validation period based on the Nash-Sutcliffe index, emphasizes the efficiency of WetSpa model in the simulation of Shazand catchment.