Fuzzy logic techniques and GIS-based delineation of groundwater potential zones: a case study of Anger river basin, Ethiopia

Abstract

As the demand for drinking water worldwide increases for human consumption, agriculture and industrial uses, the need to assess the potential of groundwater and aquifer productivity also increases. Access to water supply in Ethiopia is among the lowest in the world. In some regions of Ethiopia, people make three–five round trips to get dirty water from the river per day. Each roundtrip takes 2–3 h and water is carried in around “50-lb jerrycans” according to an article by Tina Rosenberg for National Geographic. Therefore, delineation of groundwater potential in Ethiopia is a need of an hour. The objective of this study is to develop a spatial model using a fuzzy logic approach integrated with geographic information system (GIS) domain to demarcate the groundwater potential zones (GPZ) of Anger river basin Ethiopia. Nine thematic layers such as geology, slope gradient, drainage density, Roughness, profile curvature, plan curvature, wetness index, soil texture, soil type, and land use were prepared, analyzed and studied for GPZ delineation. The groundwater potential zone map thus obtained was categorized into five classes: very good, good, moderate, low and very low. The study reveals that about 28.44% of the Anger river basin is covered under very good GPZ. Very poor, poor, moderate and good GPZ are observed in 8.06%, 15.47%, 21.36%, and 26.67%, respectively. The area under very poor and poor potential zones is recorded only in very limited areas in the basin. This study proved the efficiency of the fuzzy logic approach coupled with GIS an efficient model for demarcation of GPZ and can be applied at a continental scale.