Assessment and Improvement of Groundwater Vulnerability Mapping Using the DRASTIC Model in Wadi Shuaib Sub-Basin, Jordan

Jordan, an arid to semi-arid and extremely water-scarce country, relies heavily on groundwater, rendering the Wadi Shuaib sub-basin a critical yet vulnerable resource. Contamination threats from septic-tank leakage, overflows from the Assalt and Fuhais wastewater treatment plants, and diffuse agricultural pollutants necessitated assessing and refining groundwater vulnerability via the DRASTIC index in a GIS framework. The standard DRASTIC model, utilizing seven hydrogeological parameters from hydrological, geological, soil, land-use, and well data, produced a vulnerability map classifying the 172 km² basin into five categories: very low to very high. About three-quarters of the area exhibits low to very low vulnerability, while high (6%) and very high (5%) classes concentrate in the south-western sector, driven by shallow water tables (