Assessment of Groundwater Potential for Urban and Peri-urban Irrigated Agriculture in the Wa Municipality of Ghana

Abstract

The increasing dependence on groundwater for domestic and irrigation purposes, especially in the context of climate variability necessitates the identification of areas with high groundwater potential. This study aimed to delineate groundwater potential zones in the Wa Municipality of Ghana to support urban and peri-urban irrigated agriculture using ArcGIS 10.3. Key physical and environmental factors, including geology, lineament density, rainfall, drainage density, soil type, landuse/landcover (LULC), topographic wetness index (TWI), slope, and elevation, were integrated and assigned weights based on their relative influence on groundwater occurrence. The weighting process employed the Analytic Hierarchy Process (AHP), yielding an acceptable consistency ratio of 0.088. The analysis revealed that 185.33 km² of the study area possesses very high groundwater potential, while 112.39 km² falls under high potential. Moderate and low potential zones cover 130.15 km² and 145.71 km², respectively. Validation using existing well data showed a prediction accuracy of 87%, confirming the reliability of the delineated zones. The study therefore revealed that, the Wa Municipality demonstrates considerable groundwater potential suitable for irrigated agriculture. The results provide a valuable decision-support tool for stakeholders and policymakers in promoting sustainable groundwater management. Furthermore, in areas identified with low groundwater potential, the implementation of recharge-enhancing interventions such as injection wells, fish ponds, and dugouts is recommended to support aquifer replenishment.