Groundwater salinization process in the coastal aquifer Sidi Abed-Ouled Ghanem (Province of El Jadida, Morocco)

In this work, the salinization mechanisms were highlighted in the coastal area between Sidi Abed and Ouled Ghanem (El Jadida Province, Morocco). This study was based on analyzing and discussing the physicochemical data of water samples from 73 wells distributed in the whole studied region. Firstly, the results of the principal component analysis (PCA) and hierarchical cluster analysis (HCA) showed that the study area is composed of three main groups. This classification is firstly based on the proximity of the wells to the seawater. In fact, it was found that the first and second groups of wells which are located in the coastal fringe are characterized by high concentration of sodium and chloride and EC values whereas lower values are found in the third group that is located in upstream. Moreover, the results also showed the influence of the hydrogeological characteristics of the area where the wells are located on the composition of the water samples. The evaluation of the hydrochemical facies using Piper trilinear diagram have also confirmed these results and showed the probable contribution of seawater intrusion in the modification of wells composition by ion exchange process and by increasing the concentration of sodium and chloride. Then, the groundwater quality were assessed using Sodium Adsorption Ratio (SAR) and sodium percentage (Na %) parameters. In order to define the salinization processes occurring in the aquifer, the binary diagrams between chloride and the other elements were plotted. It was found that the groundwater is contaminated by seawater intrusion which is accompanied by ions exchange depending on the hydrogeological characteristics of the area.