Integrated assessment of groundwater pollution vulnerability in Goulmima: a comparative analysis of DRASTIC and GOD methods

This study presents a comprehensive groundwater vulnerability assessment conducted in the Goulmima palm grove of southeastern Morocco, a region facing potential risks of groundwater pollution due to natural and anthropogenic factors. In this study, the DRASTIC and GOD methods were used to identify areas highly, moderately, and weakly vulnerable to pollution. The aquifer's characteristics, geological formations, and climatic conditions are thoroughly analyzed in this arid oasis environment. The DRASTIC method evaluates parameters such as soil media, topography, hydraulic conductivity, depth to the water table, aquifer media, impact of the vadose zone, and net recharge. Meanwhile, the GOD method focuses on aquifer vulnerability to vertical percolation of pollutants. DRASTIC reveals that 72.23% of the area has a moderate vulnerability, with lesser extents of low (10.88%) and high (16.89%) vulnerabilities. GOD highlights 44% of the area as highly vulnerable, with medium and low vulnerabilities at 40% and 16%, respectively, showcasing different risk assessments between methods. Validation through electrical conductivity and nitrate data confirms a correlation between the vulnerability maps produced by the DRASTIC and GOD methods and the observed contamination levels. The findings emphasize the need for sustainable water resource management strategies, inclusive land use planning, and collaborative efforts among stakeholders to address identified constraints and ensure responsible development in the Goulmima aquifer.