Using resistivity methods to characterize the geometry and assess groundwater vulnerability of a Moroccan coastal aquifer

Abstract The inter-urban aquifer of Martil-Alila is located in a coastal zone where the water resources management is a major challenge because of the increasing pollutant discharges due to the strong anthropogenic pressure. Urgent, continuous and well-studied protection measures should be taken to avoid the complexity of these problems and to restore its perfect state. In this paper, a comparative analysis of five empirical approaches (DRASTC, SINTACS, GOD, GODS and AVI) and a geophysical approach (Groundwater Protection Index - GPI) is carried out to contrast their cartographic results in order to assess the reliability of this latter. The vulnerability outputs have been correlated with geochemical and bacteriological water quality analysis which validate the results of the GPI approach in our case. This last has the advantage of being based on abundant, well-distributed, recent and reliable geophysical field data and, thence, it is more useful in comparison with the results of traditional empirical methods where data is often lacking or insufficient.