Investigating aquifer vulnerability and pollution risk employing modified DRASTIC model and GIS techniques in Liwa area, United Arab Emirates

Anthropogenic activities and land use types can have a significant impact on the groundwater vulnerability especially in areas with agricultural activities such as Liwa area in the United Arab Emirates (UAE). In the study area, the groundwater resources over-exploited and are prone to quality deterioration due to the urbanization and growth in the agriculture sector. In the present study, various parameters and techniques were considered to represent the data variation and to analyze the water quality, e.g. vulnerability mapping and DRASTIC model. Estimates of the parameters, such as recharge potential, soil media, and vadose zone were obtained based on modified criteria to account for the data variability. Statistical analysis indicates that the input parameters are independent and contribute individually to the vulnerability index. Based on the vulnerability index the study area is classified into low to very high vulnerability classes. The land use pattern was included as one of the parameters to assess the human interaction on the groundwater resources in the study area. To analyze the model sensitivity, two techniques, i.e., the map removal sensitivity and the single parameter sensitivity analysis were used. DRASTIC vulnerability index (DVI) was calculated by the linear additive combination of seven hydrogeological parameters with weights and ratings. The single parameter sensitivity measure was developed to measure the impact of each of the DRASTIC parameters on the DVI.