Geospatial mapping of groundwater potential zones using multi-criteria decision analysis and GIS fuzzy logic in Dabus Sub-Basin, western Ethiopia

Abstract

Ethiopian groundwater assessments are often conducted using field surveys as a basis. Although conventional groundwater exploration methods yield results of varying scale and improved quality, they are typically costly and time-consuming tasks. Utilizing remotely sensed data and geographic information systems (GIS), data may now be efficiently collected, analyzed, and managed across extensive spatial and temporal scales. This study will use timely, affordable remote sensing (RS) data and GIS approaches to map the groundwater potential in the Dabus Sub-Basin in Western Ethiopia. This study examines various geographic parameters, including lithology, slope, rainfall, drainage density, lineament density, soil texture, land use/cover (LULC), and geomorphology. Weight overlay analysis and Multi-Criteria Decision Analysis (MCDA), particularly the analytical hierarchy process (AHP) method, were employed to delineate the groundwater potential zone (GWPZs). Then, using Saatty's (AHP) scale, the weights for each element were allocated based on their relative relevance. The results of the primary components show that lithology has the lowest weight and rainfall, and geomorphology has the highest weights when calculating the prospective groundwater potential zone in the research region. The findings showed that approximately 310.2 km² (1.5%) had very high groundwater potential, 16216 km² (77.1%) had high groundwater potential, 4476 km² (21.3%) had moderate groundwater potential, and 27.77 km² (0.13%) had low groundwater potential. After employing borehole points and the Receiver Operating Characteristic (ROC) curve method to assess the created groundwater potential zone map, a good correlation of 73.8% was found. Thus, this study demonstrates a reliable way to utilize GIS and remote sensing tools to map and define GWPZs. To make prompt judgments about groundwater management, planners and decision-makers rely heavily on the GWPZ that is produced.