Assessment of groundwater vulnerability using GIS-based COP model in the northern governorates of Jordan

Groundwater is the main source of water supply in Jordan. Despite its importance, it suffers from pollution resulting from excess use or misuse of fertilizers and pesticides, unsafe land-filling and inadequate treatment of industrial and domestic wastewater. This makes the management of the available groundwater resources one of the country's most critical priorities to save water for future generations. Within this study, an assessment of groundwater vulnerability for the northern governorates of Jordan was performed using the COP (C-flow concentration, O-overlying layers, P-precipitation) vulnerability method. Data related to geology, hydrology, hydrogeology, climatology, and land use are employed to assess the vulnerability of the groundwater in the study area. The results of this research indicate that the study area contains five vulnerability classes [very high (0.09%), high (38.86%), moderate (6.84%), low (6.77%), and very low (47.44%)]. The resulting model was validated using nitrate concentrations, the validation process showed a strong negative correlation between the nitrate concentrations and the COP index (R-2 = - 0.98). As well as, a map removal sensitivity analysis is conducted on the resulting model; the results show that the 'concentration of flow' (C) factor is the most significant parameter in the model. The vulnerability assessment results provide useful information that can support the decision-making and the formulation of new policies and regulations for sustainable groundwater.