Modeling Erbil’s water supply–demand balance using WEAP under future population growth and groundwater operation scenarios

Erbil is experiencing a severe water shortage. Following the implementation of the Emergency Water Supply Project, we developed a long-term adaptation strategy to ensure adequate water supplies for all users from 2025 to 2065 using the Water Evaluation and Planning (WEAP) model. “The WEAP model was implemented over the 2025–2065 planning horizon. Two population-growth scenarios, 3.0% and 5.0%, were evaluated under alternative groundwater-well operation conditions. The analysis estimated the timing and magnitude of future unmet demand and supported the development of a phased adaptation. The model was developed based on a population of 1,600,000 (in 2024), a per capita domestic water consumption of 350 litres per day, an agricultural water consumption of 3,500 cubic meters per hectare, and an average annual production capacity for the entire region of 347.78 million cubic meters. The results indicate that current surface water development will not keep pace with demand, leading to supply shortages by 2047 if the population grows by 3.0%, and by 2038 if it grows by 5.0%. While the baseline scenario (well closures) projects a maximum monthly deficit of 11.58 million cubic meters in March 2047 at a 3.0% growth rate, the high-growth scenario (well closures) projects a maximum monthly deficit of 5.6 million cubic meters in September 2038 at a 5.0% growth rate. Reactivating the 1,600 suspended wells delays the first monthly deficit under 3.0% population growth until July 2057, when unmet demand reaches 7.63 MCM. Under 5.0% growth, the combined surface-water and groundwater system develops a monthly deficit of 17.73 MCM by June 2047. These results indicate that the existing infrastructure will be insufficient to meet demand during the study period across all growth scenarios, underscoring the need for phased, timely interventions based on the modeled deficit timelines. This paper concludes with a three-phase, time-bound adaptation plan that prioritizes immediate demand control or wastewater reuse, followed by the development of a new transportation project connecting the existing Gomaspan Dam reservoir to Erbil by 2045.