Integrated approach to identify suitable sites for percolation tanks to enhance groundwater in Kesem sub-basin

The study was conducted in the Kesem sub-basin of the Awash River Basin, Ethiopia, a semi-arid region facing increasing water scarcity and high dependence on groundwater for domestic and agricultural use. This research identifies suitable sites for percolation tanks to enhance groundwater recharge using an integrated Geographic Information System (GIS), remote sensing (RS), the Soil and Water Assessment Tool (SWAT), the Fuzzy Analytical Hierarchy Process (FAHP). Thirteen factors were considered, including: rainfall, runoff, drainage density, topographic wetness index, stream order, proximity to wells, slope, lineament density, lithology, land use/land cover, soil texture, and proximity to settlements and roads. Runoff was simulated using the SWAT model, which showed strong performance (NSE = 0.77, R² = 0.79 during calibration; NSE = 0.77, R² = 0.76 during validation). FAHP was applied to determine the weights of each criterion, fuzzy membership functions were used to standardize inputs, and a gamma fuzzy overlay technique was employed for factor integration. The suitability analysis revealed that only 3.26 % of the sub-basin is classified as very highly suitable for percolation tanks, while 9.55 %, 17.56 %, 30.66 %, and 38.98 % fall within the high, moderate, low, and very low suitability classes, respectively. The resulting spatial prioritization provides a scientifically validated basis for groundwater recharge enhancement and offers a practical decision-support tool for regional water management and rainwater harvesting planning. • Integrated SWAT–RS–GIS–FAHP framework for groundwater recharge site mapping. • Fuzzy dynamic weights improve reliability beyond fixed-weight approaches. • Suitability maps guide recharge site prioritization to curb groundwater loss. • Scalable approach applicable in data-scarce, climate-vulnerable basins. • Supports evidence-based groundwater policy in arid and semi-arid regions.