Assessing the Impact of Climate Change on Aras River Flow (Case Study: Ardabil Province)

The purpose of this study was to evaluate the effects of climate change on Aras River catchment discharge at different time scales. In this study, RCP2.6, RCP4.5 and RCP8.5 scenarios for the near future (2017-2036) were used to analyze the future and predict the minimum and maximum future changes of Aras discharge. Climate scenario outputs were entered into SWAT model for calibration and validation period and their results were analyzed. Monthly rainfall data of Pars Abad Synoptic Station during the period of 1985-2005 were used as control period. To evaluate and compare the accuracy of finely scaled data, comparison of baseline data and historical data produced by the model was performed using the calibration parameters. According to the results, all three scenarios predicted an increase in precipitation for August and December and a decrease for April and November, but the average annual precipitation in the Aras watershed during the period 2017-2036 will decrease. All three scenarios also predict an increase in the minimum and maximum temperatures. Although according to SWAT model results, the inlet discharge of Aras River should decrease by 30.7, 30.2, and 22.2% under scenarios RCP8.5, RCP4.5 and RCP2.6 respectively. In general, and based on the results of the models used, the temperature in the study area will increase and precipitation will decrease, which will have a negative impact on the Aras River discharge and will require proper and principled management of water resources utilization.