Investigating of Climate Change Effects on the Surface Runoff with SWAT Model (Case study: Mazlaghan River)

The purpose of the present study was Investigating of Climate Change Effects on the Surface Runoff of the Mazlaghan area. For this purpose, SWAT model was used to simulate basin hydrological regime and SUFI-2 algorithm in SWAT-CUP software to optimize model parameters. Statistical data used for runoff simulation were years (1997-2015). To evaluate the ability of SWAT model to simulate runoff discharge, Nash Sutcliffe, R2, p-factor and r-factor indices were used. Using the LARS-WG climate change model in the study area, map the observational data of Razin Station with long-term climate data, taking into account RCP2.6, RCP4.5 and RCP8.5 climate change scenarios for the coming period 2021- 2040 Climate change in the region was evaluated.. LARS-WG model to ensure the correct calibration errors indices of average root mean square error (RMSE), mean absolute error (MAE) and the coefficient of productivity Nash Sutcliffe (NSE) was used; The results of the study, while confirming the efficiency of the model, showed for the period 2021-2040, an increase in the mean annual temperature will occur based on the three scenarios mentioned. Also, the average monthly rainfall under the scenarios of RCP2.6, RCP4.5 increases and RCP8.5 predicts a decrease. Finally, according to the predicted climatic data in runoff simulation, an increase in runoff is predicted in the Alluvial Basin.