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Gilgel Gibe Watershed, Omo Gibe River Basin, Ethiopia. Groundwater depletion adversely affects ecosystem health, leading to reduced vegetation cover, changes in habitat suitability, and increased vulnerability to environmental stress. Quantifying groundwater sustainability under surface water-groundwater interactions is crucial for understanding system responses to anthropogenic changes. Hence, the main objective of this study was to quantify groundwater sustainability using a novel ensemble approach of the coupled SWAT-MODFLOW model. The performance of the integrated SWAT-MODFLOW model was assessed using the Parameter Estimation Tool (PEST) with streamflow and aquifer properties, and was found to be in reasonable agreement between the predicted and observed values. Annual ensemble values of exploitable amounts of groundwater discharge, minimum desirable flow, and groundwater recharge were used to compute the groundwater footprint and sustainability. The overall basin-wide groundwater footprint was moderately depleted, revealing the need for effective management strategies to mitigate long-term groundwater decline and vulnerability to groundwater droughts. This has resulted in food insecurity due to diminished crop yields and shifting agricultural practices. Overall, this study offers valuable insights for developing informed policy frameworks that prioritise resilient watershed management to support the achievement of sustainable development goals. • Groundwater footprint estimated under SGWI using coupled SWAT-MODFLOW model. • Novel ensemble approach informs strategic, evidence-based aquifer management. • River–aquifer exchange sustains ecological flows during prolonged dry periods. • Ensemble modeling supports resilient groundwater planning and governance. • Groundwater depletion highlights policy needs and guides low-impact watershed strategies.
Mengistu et al. (Tue,) studied this question.