GIS and fuzzy logic techniques-based demarcation of groundwater potential zones: A case study from Jemma River basin, Ethiopia

Access to the water supply in Ethiopia is among the lowest in the entire world. In some regions of Ethiopia, people make three to five round trips to fetch dirty water from the river per day. Each round trip takes two to 3 h and water is carried in '50-pound jerrycans', according to an article by Tina Rosenberg for National Geographic. Therefore, delineation of groundwater potential in Ethiopia is a need of the hour. The objective of this study is to develop a spatial model using a fuzzy logic approach in the geographic information system (GIS) domain to demarcate the groundwater potential zones (GPZ). Ten thematic layers, such as geology, slope gradient, drainage density, distance to faults, profile curvature, plan curvature, wetness index, soil texture, soil type, and land use, were prepared, analysed and studied for GPZ delineation. The study reveals that about 43.78% of the Jemma River basin represents GPZ categorised as 'excellent'. 'Very poor', 'poor', 'moderate' and 'good' GPZ are observed in 22.67, 6.02, 19.88 and 7.66% of the basin, respectively. This study proves the efficacy of the fuzzy logic approach coupled with GIS as an effective model for demarcation of GPZ and can be applied at a continental scale.