Determining the Impact of Climate Change on Groundwater Drought Using CMIP6 Models (Case Study: Shahrekord Plain)

Groundwater is the most valuable water resources in any region and in many arid and semi-arid regions of the world, such as Iran, is the main source for drinking and agricultural needs. In recent years, with the increase in population and as a result of increasing withdrawals from aquifers and climate change, many of aquifers are in poor condition, and these conditions continue or are deteriorating. In this study, in order to determine the effect of climate change on groundwater drought on the aquifer of Shahrekord plain, the output of CMIP6 models and SPI and GRI drought indices have been used. Simulations of GFDL-ESM4 model show that the average rainfall by 2050 in Shahrekord plain, under scenario SSP1-2.6 will increase by 4.85 mm and under scenario SSP5-8.5 will decrease by 21.34 mm. In order to determine the effect of climate change on the aquifer of Shahrekord plain, a regression relationship between the two indices of SPI and GRI in six selected piezometers has been used. The results show that droughts with higher intensity and duration will occur in the region and more than 60 percent of the future period of Shahrekord plain aquifer will be in drought conditions and the most severe drought under SSP1-2.6 scenario will last 52 months and its severity will be 59.32 and under the SSP5-8.5 scenario the most severe drought will last 70 months and its severity will be 86.59.