Assessing future water security in Gondar City, Ethiopia: A scenario–based analysis using the WEAP model

This study employs a scenario-based analysis using the WEAP model to examine the combined effects of population growth, reservoir sedimentation, groundwater depletion, irrigation expansion, and climate variability on the water security of Gondar City. The existing water supply system, which depends primarily on the Angereb Reservoir (AR) and groundwater sources, currently meets less than 50% of demand. Planned infrastructure developments include the Megech Dam (anticipated by 2028) and the LTWPS. Eight scenarios were developed from both supply- and demand-side perspectives to assess impacts on the water supply–demand gap from 2025 to 2045. The model was calibrated using data from 2015 to 2018 and validated with data from 2020 to 2023, achieving high accuracy (NSE = 0.878; PBIAS = −0.095%; RMSE = 0.0237 MCM yr⁻¹). Under the RS, cumulative UWD could reach 374.8 million cubic meters (MCM) by 2045. Although the Megech Dam offers temporary relief, its long-term effectiveness is constrained by sedimentation (3.0–3.9% annual storage loss) and competition with irrigation. The LTWPS substantially mitigates shortages but does not fully eliminate deficits. An integrated urban water management approach combining supply diversification, sediment control, groundwater management, climate adaptation, and demand-side measures is essential for sustainable water security.