GIS based DRASTIC model for groundwater vulnerability assessment: Case study of the shallow mio-plio-quaternary aquifer (Southeastern Tunisia)

Abstract

Groundwater is the main source of water in arid regions. Thus, groundwater pollution becomes a major issue due to the increasing contamination, which poses serious and harmful risk to the environment. Groundwater vulnerability maps can be used as a tool to help decision makers to protect groundwater resources from contamination. The vulnerability of the Mio-Plio-Quaternary shallow aquifer (Southeast Tunisia) has been assessed using a DRASTIC model based on Geographic Information System (GIS). The different parameters of the model were collected from several sources and converted into thematic maps using ArcGis©. Each DRASTIC parameter was assigned a weight and rating based on a range of information within the parameter. Groundwater vulnerability map shows a large area (48%) with high risk of pollution. It indicates that the Southern part of the aquifer and the wadi beds are the most susceptible to contamination. The measured nitrate concentration is coherent with the DRASTIC model results.