Water vulnerability of coastal aquifers using AHP and parametric models: methodological overview and a case study assessment

Abstract

The concept of groundwater vulnerability is a useful tool for environmental planning and decision-making. Added to overexploitation, the increasing agricultural activities have affected water resources. The groundwater contamination is becoming an important issue, especially in coastal areas also threatened by seawater intrusion. Indeed, several methods have been developed for assessing aquifer vulnerability. This study aims to develop a comparison between the application of the DRASTIC and GALDIT standard parametric models and the AHP-DRASTIC and AHP-GALDIT combined models in order to evaluate the groundwater vulnerability in the Mahdia-Ksour Essef coastal aquifer. For a better highlighting the spatial visualization of the obtained results, we used the GIS technics. The results showed that the coastal zone is the most susceptible to the seawater intrusion. The correlation coefficients showed that the relationship between the DRASTIC and AHP-DRASTIC vulnerability indexes and the nitrate concentration was increased from 28 to 57%, respectively. Furthermore, the correlation coefficients showed that the relationship between the GALDIT and AHP-GALDIT vulnerability indexes and the electrical conductivity was increased from 41 to 69%, respectively. This requires the use of the AHP-GALDIT combined method which is considered more effective and provides good results. Obtained results could be considered as a guide for the groundwater management.