Adaptation to Climate Change Conditions in Maroon Basin

Climate change is one of the critical environmental issues that has significantly influenced the water resources availability in recent years. The purpose of this research is to investigate the climate change adaptation strategies in Maroon Basin, Iran, to balance the pre-defined water demands and the future supplies by changing the area and pattern of cultivation in the basin. To investigate the impacts of climate change on precipitation, temperature, and inflow to Maroon Dam, simulations of five General Circulation Models (GCMs) namely MIROC-ESM, MPI -ESM-MR, HadGEM2-ES, EC-EARTH, and GFDL-ESM2M were studied at three future periods of 2021-2040, 2041-2060, and 2061-2080. First, Maroon Dam inflow was simulated using the SWAT hydrological model. Then the model was calibrated and validated against monthly flow at the Idanak and Tang-e-Takab hydro-stations. The Nash-Sutcliffe efficiency (NSE) index at Idanak and Tang-e-Takab stations were estimated 0.69 and 0.67 for the calibration and 0.65 and 0.59 for the validation step. The downscaling of precipitation and temperature data under the four RCP scenarios was done using the LARS-WG model. The calibrated SWAT model was forced using the downscaled data to simulate the inflow to the dam during the three future periods. The results showed that the temperature increase projected in the catchment would significantly reduce the runoff formation in the catchment, despite the projected increase in the precipitation. The present and future Maroon Dam inflow were used as essential inputs to the MODSIM model. Water allocation to each requirement in all the periods was done by collecting other necessary information and calculating the reliability performance index. Compared with the current status, on average, allocation to the defined demands will reduce by 2 to 6.25 percent. In this research, an attempt has been made to maintain the cultivated area and reliability index in the current status by altering the cultivation pattern. Therefore, 9% decrease in alfalfa plantation area, 15% decrease in autumn grain maize, 17% decrease in wheat, 5% decrease in potato and 9% increase in barley and sesame, 15% increase in autumn silage maize, 17% increase in tomato, and 5% increase in bean in class B3 (as the most effective climate change conditions), would fulfill the premise of the study to maintain the overall cultivation area and reliability index under the climate change impacts.