Quantifying the size of climate change effect on groundwater draw down in arid and semi-arid regions

The present research aims to assess climate change in the Minab plain and its effect on groundwater level variability in the future period. Climate change was explored by the climatic model CanESM2 using the SDSM4.2 software package, and the effect of climate change on groundwater resources was quantitatively modeled in the GMS10.0.5 software package under the emission scenarios of RCP2.6, RCP4.5, and RCP8.5. The results for the effect of climate change in the future period in the context of these scenarios showed that temperature will increase by 1.88ºC, 2.60ºC, and 4.28ºC and precipitation will decrease by 34.19%, 42.08%, and 59.43% versus the reference year, respectively. The results for the application of the climatic scenarios using the groundwater model revealed that due to the decline of precipitation in this period, mean groundwater level balance in the future periods leading to 2019, 2024, 2029, and 2035 versus the reference year (2003-2004) will be -13.99, -19.003, -22.70, and -25.61 m/yr in RCP2.6, -13.99, -18.95, -22.75, and -24.73 m/yr in RCP4.5, and -14.23, -19.22, -22.003, and -25.46 m/yr in RCP8.5, respectively. This shows that the drawdown will be being aggravated over time. Finally, this decline of precipitation and rise in temperature due to climate change and the subsequent increase in water abstraction for different uses will result in the growing depletion of the groundwater tables in Minab. So, it is recommended to planners and authorities to adopt strategies for adaptation to new climatic conditions and water scarcity and accommodate themselves with future conditions.