GROUNDWATER POTENTIAL ASSESSMENT USING GEOSPATIAL AND AHP TECHNIQUES IN GOMBORO RIVER WATERSHED OF OMO GIBE BASIN, ETHIOPIA

Groundwater is an essential resource for industrial, agricultural, and human uses. Prospecting high-potential groundwater availability areas and optimal places for groundwater resource development in arid regions with variable rainfall patter is crucial. The Analytic Hierarchy Process (AHP) along with Geographic Information Systems (GIS) is used in this study to evaluate the groundwater potential zones of the Gomboro watershed, Omo Gibe basin, Ethiopia. Integrating these two methods enables the development of a comprehensive and precise map of groundwater potential zones. The groundwater potential zones are defined based on a variety of thematic maps that include information on the geology, soil texture, lineament density, slope, land use, and drainage density. These data layers are combined using the AHP approach, which weights each layer according to its relative relevance to groundwater recharge. These weighted layers are overlaid using a GIS platform to construct a final map of groundwater potential zones. The groundwater potential of the watershed is then qualitatively categorized into five classes: very good (2.22%), good (26.93%), moderate (56.74%), poor (13.84%), and very poor (0.26%). The accuracy of the groundwater potential zone was tested using the receiver operating characteristic (ROC) curve's area under the curve (AUC), and the results were good (AUC = 75.5%). This study has demonstrated that combining AHP with GIS is helpful for identifying groundwater potential zones. Moreover, the outcome could be instrumental in locating new groundwater wells and providing information for decision-makers for planning and sustainable groundwater resource management strategies in the watershed.