Groundwater potential zone delineation using integrated geospatial data and AHP technique: a case study of the Gidabo Watershed, Ethiopia

Groundwater demand in Ethiopia is rising rapidly due to population growth, urbanization, and agricultural expansion projects. However, groundwater assessment in the country is predominantly conducted through conventional hydrogeological and geophysical resistivity surveys, which are time-consuming and expensive. To address this challenge, this study investigates the use of integrated remote sensing and GIS-based techniques combined with the multi-criteria decision analysis (MCDA) AHP method to map groundwater potential zones in the Gidabo watershed, Ethiopia. Sentinel-1A SAR (RADAR) and Sentinel-2A optical imagery, ALOS DEM, geological maps, and soil data were utilized to extract nine key factors influencing groundwater occurrence such as land use/land cover (LULC), slope, elevation, soil moisture, soil texture, lineament density, geology, rainfall, and drainage density. These factors were assigned weights based on their relative importance to groundwater availability using the AHP technique, and the weighted thematic layers were aggregated in the ArcGIS environment using a weighted overlay method. The results reveals that the watershed with varying groundwater potential, categorized as very low (0.006%), low (14.951%), moderate (60.188%), and high (24.856%). Notably, 75% of the study area has moderate to high groundwater potential, with specific high-potential zones identified northwest of Dilla town and its surroundings. These findings suggest that geospatial technologies provides a practical and efficient approach to groundwater resource assessment. The study recommends further detailed investigations, incorporating expertise from geology, hydrology, and environmental science, to optimize groundwater exploration and address water scarcity challenges in the watershed.