Depletion zones of groundwater resources in the Southwest Desert of Iraq

Abstract Aquifers offer a reliable supply of high-quality water, making groundwater significant in arid and semi-arid regions. Climate change is predicted to result in a decrease in rainfall and an increase in droughts. The prolonged drought severely devastated Iraq and is the main reason for the ongoing increase in groundwater consumption over the last decade. In this study, the stresses and depletion potentials of the Dammam confined aquifer, which extended along the Najaf and Muthanna governorates, are identified and analyzed. By using the Groundwater Modelling System (GMS v10.4) software, a numerical simulation of groundwater flow was used to study the Dammam aquifer system. The upper layer was modeled as unconfined, while the bottom layer was confined. The findings from the steady-state calibration indicate that the hydraulic conductivity (HK) within the study area varies between 1.47 to 20.0 m/day. Additionally, the recharging rate (RH) was estimated to be approximately 1.66 × 10−6 m/day. These parameters were utilized as the initial condition for conducting the transient analysis. Two operating scenarios were employed to perform unsteady simulations. The initial scenario involved the utilization of 89 production wells, while the second scenario included all 139 stand-by production wells, resulting in a total of 228 wells for the operational period from July 2021 to June 2022. The results of the first operation scenario showed that the drawdowns ranged from 0.4 to 5.8 m, whereas the second operation scenario showed that the drawdown increased from 1.0 to 22 m. The depletion rate in the groundwater static heads was measured by the percentage of relative difference. Hence, the depletion rate for the first scenario varied from 4.32 to 33.34%. On the other hand, the second scenario ranged from 7.45 to 33.34%.