Delineating the Impact of Climate Change on Precipitation and Groundwater Level Fluctuations in A Semi-Arid Region of Iran

Document Type : Original Research Article

Authors

School of Energy Engineering and Sustainable Resources, College of Interdisciplinary Science and Technology, University of Tehran, Tehran, Iran

Abstract

In this study, the impacts of climate change on Kashan’s groundwater resources were assessed by utilizing outputs from general circulation models (GCMs) and downscaled precipitation data using the SDSM model. For downscaling, the CanESM2 model was applied under the RCP2.6, RCP4.5, and RCP8.5 scenarios to determine precipitation values for future periods. Subsequently, we developed a groundwater model of the aquifer in both steady-state and transient modes using the MODFLOW code within the GMS modeler, based on the hydrological and hydrogeological conditions of the Kashan aquifer. The results of climate downscaling under the CanESM2 model in two scenarios indicated that precipitation percentages during the simulated period of the aquifer (2017-2023) under the RCP2.6, RCP4.5, and RCP8.5 scenarios were 1.17%, 11.77%, and 14.01%, respectively. The reduced precipitation percentages in the climate scenarios of the aquifer model and the magnitude of changes in the water table level for the three scenarios were estimated over 83 time steps. The changes in the water table level during the base period (2016) indicated a decrease of 0.069 m, 0.75 m, and 0.78 m compared to the previous seven-year simulation (2016-2023) at the last time step in the RCP2.6, RCP4.5, and RCP8.5 scenarios, respectively. In light of these climate changes, climate parameter alterations directly correlate with recharge, which could be managed through appropriate water table exploitation practices. Such management necessitates a robust program to compensate for reservoir depletion and mitigate further intensification of water table decline in the area.

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