Evaluation of groundwater potential using geospatial techniques and gravity data in the Baja sub-watershed, western margin of the Afar Depression, Ethiopia

Water is essential for life and socio-economic development, yet increasing population pressure and climate change are intensifying freshwater demand. This study delineates groundwater potential zones (GWPZ) in the Baja sub-watershed by integrating geospatial techniques with gravity data to assess surface and subsurface controls on groundwater occurrence. Nine thematic layers: geology, slope, land use/land cover, geomorphology, elevation, soil texture, rainfall, lineament density, and drainage density were evaluated using Multi-Criteria Decision Analysis (MCDA) and the Analytical Hierarchy Process (AHP). The resulting GWPZ map classifies the area into high (12.35 km², 2.93%), moderate (316.80 km², 75.11%), low (92.58 km², 21.95%), and very low (0.06 km², 0.01%) potential zones. High-potential zones are concentrated in the southwestern, southern, and northern parts of the watershed, whereas rugged volcanic terrains in the east and northwest exhibit low potential. Gravity data reveal N–S-oriented subsurface structures acting as groundwater barriers, while NNE–SSW lineaments derived from satellite imagery indicate shallow aquifer systems associated with springs. Validation using 46 well data produced an AUC value of 0.74, confirming good predictive accuracy. This integrated approach supports sustainable groundwater management in climate-affected, water-scarce regions.