Integrated GIS, remote sensing, and analytical hierarchical process approaches to delineate groundwater storage zones in the Sub-Saharan region of Northern Ethiopia

<h2>Abstract</h2> Groundwater is a crucial, naturally fresh water source that is easily accessible and can be quickly and cost-effectively directed to rural areas. However, climate, land use changes, and population growth have all contributed to the growing demand for water. Therefore, demarcating groundwater storage areas is critical to ensure their sustainable use. This study aims to assess groundwater storage zones in northern Ethiopia's Sub-Saharan region using integrated geographic information systems, and multi-criteria decision analysis of the analytical hierarchy process approaches. In this study, ten key factors, including geology, geomorphology, slope, land use/cover, soil texture, lineament density, groundwater level, drainage density, rainfall, and topographic wetness index, were considered. Pairwise comparison matrices were used to assess the relative importance of these factors, and expert ratings, along with correlation analysis, determined their significance. Weighted overlay analysis was used to identify groundwater potential zones (GWPZ). The results indicated that a very good GWPZ covers 20.57 % (310.12 km²), a good GWPZ covers 34.22 % (515.83 km²), a moderate GWPZ covers 29.98 % (451.90 km²), and a poor GWPZ covers 15.23 % (229.52 km²), respectively. The groundwater potential zone revealed that the central north and southeastern parts of the study areas have significant groundwater potentials. Validation utilized the receiver operating characteristic (ROC) curve method. Cross-validation of the groundwater potential zones against 81 point-source inventory data yielded a 77 % area under the curve (AUC) value. The ROC is acceptable due to an AUC value exceeding 70 %. This integrated approach is crucial for hydrogeologists, decision-makers, and groundwater resource planners to optimally locate water supply projects and mitigate groundwater risks in the area.