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Recently, many studies have investigated the effect of climate change on groundwater resources in semiarid and arid areas and have shown adverse effects on groundwater recharge and water level. However, only a few studies have shown suitable strategies for reducing these adverse effects. In this study, climate conditions were predicted for the future period of 2020-2044, under the emission scenarios of RCP2.6, RCP4.5, and RCP8.5, for Isfahan-Borkhar aquifer, Isfahan, Iran, using MODFLOW-2000 (MODFLOW is United States Geological Survey product). Results showed that the average groundwater level of the aquifer would decrease to 13, 15, and 16 m in 2012 to 2044 approximately under RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively. Then, three groundwater sustainability management scenarios were defined that included 10%, 30%, and 50% reduction in groundwater extraction. These strategies simulated the reduced negative effects of climate change on the aquifer.The results showed that decreases in water withdrawal rates of 10%, 30%, and 50% under RCP8.5 scenario (critical scenario) could decrease the mean groundwater level by 14, 11, and 7 m, respectively. The main result of the study showed that 50% reduction in groundwater withdrawal may increase the groundwater levels significantly in order to restore the aquifer sustainability in the study area. In this study, with assuming that the current harvest of wells in the future period is constant, so the results of studies showed that for the aquifer's sustainability management, the water abstraction from the aquifer should reduce up to 50% of the existing wells.Changing the irrigation method from surface to subdroplet irrigation plays an important role in reducing the withdrawal from the aquifer. The results of a study in Iran have shown that the change in the irrigation method from surface to subdroplet irrigation causes a 40% reduction in water use for agriculture.

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Global warming affected by human activities causes changes in the regime of rivers. Rivers are one of the most vital sources that supply fresh water. Therefore, management, planning, and proper use of rivers will be crucial for future climate change conditions. This study investigated the monitoring of hydrological drought in a future period to examine the impact of climate change on the discharging flow of the Zard River basin in Iran. Zard River is an important supplier of fresh and agricultural water in a vast area of Khuzestan province in Iran. A continuous rainfall-runoff model based on Soil Moisture Accounting (SMA) algorithm was applied to simulate the discharge flow under 10 scenarios (obtained from LARS-WG.6 software) of future climate change. Then, the Stream-flow Drought Index (SDI) and the Standard Precipitation Index (SPI) were calculated for each climate change scenario for the future period (2041–2060). The results of the meteorological drought assessment showed that near normal and moderate droughts had higher proportions among other drought conditions. Moreover, the hydrological drought assessment showed the occurrence of two new droughts (severe and extreme) conditions for the future period (2041–2060) that has never happened in the past (1997–2016).