Delineation of Potential Groundwater Recharge Zone: A Case of West Wollega Zone, Western Oromia, Ethiopia

Abstract

Groundwater is a valuable and essential natural resource worldwide, playing a crucial role in the growth and development of nations. However, gaps in information related to identifying potential recharge zones for groundwater can hinder economic progress. The study was conducted to delineate groundwater potential recharge zones in West Wollega zone, Oromia Regional State, Ethiopia. The study utilized various input data, including rainfall, lithology, slope, drainage density, lineament density, land use/land cover, and soil in a raster format. Thematic maps were created for selected parameters using overlay analysis. Weight assignment and normalization were carried out using the analytical hierarchy process. After weight normalization and ranking, the thematic maps were combined using GIS version 10.7.1 software to create an overall groundwater potential recharge zone map for the study area. The resulting groundwater potential zones were classified into four categories: very high, high, moderate, and low zones. It is observed that the study area, covering 16.22km2 (0.324%), falls under the very high groundwater potential zone, 2596.9km2 (55.01%), was classified as high potential zones, 2711.9 km2 (43.1%), are categorized as moderate potential zones, and parts of the study area, covering 90.7 km2 (1.814%), is classified as low potential groundwater recharge zone. To assess the accuracy of the predictions, observed borehole yield data was compared to the predicted data for the respective locations. The results showed a prediction accuracy of 78.9%, indicating that the method used in this study produced highly reliable results.