Geospatial and satellite gravity-based assessment of groundwater potential in the Borkena Watershed, Northern Ethiopia

Abstract

Study region

Borkena Watershed, located in the Amhara regional state, Northern Ethiopia

Study focus

In the water-stressed Borkena Watershed of Northern Ethiopia, identifying reliable groundwater sources is vital for sustaining livelihoods and agriculture. This study delineates aquifer potential zones using an integrated geospatial framework combining GIS, satellite gravity data, and Multi-Criteria Decision Analysis. Eight aquifer potential controlling parameters, elevation, lithology, lineament density, slope, rainfall, land use/land cover, soil type, and drainage density, were weighted via the Analytical Hierarchy Process to reflect their influence on groundwater occurrence. Satellite-derived gravity anomalies (e.g., Free-Air and Residual anomalies) enhanced subsurface characterization, improving the precision of aquifer mapping.

New hydrogeological insight for the region

The resulting aquifer potential zones classified the watershed into five categories: very high (11.3 %), high (21.7 %), moderate (27.6 %), low (22.9 %), and poor (16.5 %) groundwater potential. Over 60 % of the watershed falls within the moderate to high groundwater potential zones, indicating that the area presents promising conditions for groundwater development. These Zones are characterized by fractured volcanic rocks, alluvial sediments, high lineament density, gentle slopes, and low drainage density, showing superior infiltration and storage capacity. Validation of the aquifer potential zones using 16 georeferenced groundwater points yielded a 75 % spatial agreement, supported by a ROC curve accuracy of 73.5 %. Moreover, the delineated aquifer potential zones were found to be consistent with the results of the satellite-derived gravity analysis. This study supports SDG 6 (Clean Water and Sanitation) and SDG 13 (Climate Action) by promoting climate-resilient and cost-effective approaches to water resource planning. In addition, the findings provide a reliable and economical method for groundwater exploration in semi-arid and data-scarce regions, offering practical insights for policymakers and planners involved in sustainable groundwater development and management.