Assessing and modeling water demand of Bontanga reservoir in Northern Region of Ghana. By Davis Sibale, Gordana Kranjac-Berisavljevic, Shaibu Abdul-Ganiyu, in: Sustainable Water Resources Management |2/2025.
Bontanga reservoir is the largest reservoir in Northern Region of Ghana and serves a number of communities through irrigation, fisheries, livestock and domestic water uses. This study was conducted to assess and model water demand of the Bontanga reservoir. The Water Evaluation and Planning (WEAP) tool was employed to simulate water demand under various ranges of overall irrigation efficiency. ANOVA results (p < 0.001) showed that seasonal water demands from multiple users differed significantly at 5% level of significance. Irrigation formed the largest seasonal water demand (42.92%), while domestic and livestock water demands accounted for only 3.09% and 0.41%, respectively. The WEAP model performed well as revealed by Nash–Sutcliffe Efficiency (NSE): 0.65, Index of agreement (d): 0.90, and Coefficient of Determination (R2): 0.85. The results indicated that the future seasonal unmet water demand is likely to reach 2,482,519 m3 by the year 2030, however, by improving overall irrigation efficiency from 31.30 to 60%, WEAP model projected that total seasonal water demand could drop by 16.50% contributing to an average seasonal water saving of 3,894,597.86 m3 during the simulation period (2024–2030). The study gives an insight to managers and Water User Associations to incorporate modeling approaches as decision supporting tools in planning sustainable water management strategies to meet the competing water demands. There is also a direct linkage of the research study to the fulfillment of Sustainable Development Goal (SDG) No. 6 which ensures access to clean water and sanitation for all by 2030.
