Groundwater vulnerability assessment and evaluation of human activity impact (HAI) within the Dead Sea groundwater basin, Jordan

Groundwater vulnerability to contamination was determined within the Dead Sea groundwater basin, Jordan, using the DRASTIC model and evaluation of human activity impact (HAI). DRASTIC is an index model composed of several hydrogeological parameters and, in this study, the recharge parameter component was calculated as a function of rainfall, soil permeability, slope percentage, fault system, and the intersection locations between the fault system and the drainage system, based on the hydrogeologic characteristics of hard-rock terrain in an arid region. To evaluate the HAI index, a land use/cover map was produced using an ASTER VNIR image, acquired for September 2004, and combined with the resultant DRASTIC model. By comparing the DRASTIC and HAI indices, it is found that human activity is affecting the groundwater quality and increasing its pollution risk. The land use/cover map was verified using the average nitrate concentrations in groundwater associated with land in each class. A sensitivity analysis was carried out in order to study the model sensitivity. The analyses showed that the depth to water table and hydraulic conductivity parameters have no significant impact on the model, whereas the impact of vadose zone, aquifer media, and recharge parameters have a significant impact on the DRASTIC model.