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The coastal aquifer of the Essaouira syncline (Morocco) was studied to identify the main processes at the origin of the salinization of groundwater. In fact, a multicriteria analysis approach on hydrochemical data and physicochemical parameters of the Plio-Quaternary aquifer was used to understand their spatiotemporal variation and their origins. Currently, integrated water resources management has become paramount to both local, regional, national and international. This management is favored by extreme hydrological events (droughts or oods) which can have direct in uences on human, economic and political aspects. Appropriate management of a resource requires its evaluation. The statistical study by Kohonen's self-organized classi cation (SOM) of hydrochemical data for the years 1995 and 2009 is used to process 47 samples distributed over the entire study area; it showed an evolution of the values of the parameters. Physico-chemical as a function of time and space with an increase in the values of the parameters, from the center of the study area towards the southwest. aquifer, the stresses applied to the aquifer (pumping, etc.) and the ow of fresh water and salty exchanging with the surrounding environment (Karroum etal., 2017). This situation is all the more critical as the groundwater in this study area (Essaouira coastal area) constitutes the only water resources available to local populations (Ouzerbane et al. 2014 ;Bahir et al. 2019). This study will take place in the context of regional planning. It will make it possible to prepare, con rm or supplement the orientations and choices necessary for a harmonious development of the region taking into account, as far as possible, all the needs and the corresponding constraints. Geographical And Geological LocationThe Essaouira basin is a coastal area located in the center-west of Morocco. It belongs to the Moroccan Atlantic margin and covers approximately an area of 20,000 km² of the eastern Mesozoic passive margin of the central Atlantic Ocean. The basin is limited to the north by the Tensiftriver, to the south by the western High Atlas, to the east by the plains of Imi-N-Tanoute and Chichaoua and to the west by the Atlantic Ocean. It is a plateau, slightly raised to the South and to the North, gently sloping down towards the Atlantic Ocean then suddenly lowering to give rise to the coastal zone with dune relief.The study area known as the synclinal Essaouira is part of the coastal area of the basin. It is bounded to the north by Qsob river, to the south by Tidziriver, to the east by the reliefs of Haha North and by the diapir of Tidzi and to the west by the Atlantic Ocean. It is not very rugged and is characterized by a relief of low hills with altitudes between 0 and 800 meters, modeled by a low density hydrographic network which ows into the Atlantic Ocean (Fig. 1).Geologically, the formations outcropping in the synclinal zone of Essaouira are generally Quaternary and Plio-Quaternary in age (Fig. 2). Going from the South to the North of the study area, th...

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The geophysical study using the VES and the ERT, carried out in the coastal area of Essaouira (Morocco), for the purpose of mapping the aquifers by combining the two geo-electrical methods, the results allowed us to determine the lateral and vertical distribution of the geological formations in the study region. Thereafter the exploitation of these results by the decision makers in the choice of the sites likely to be hydrogeologically fertile to answer the need for the inhabitants in resource in water. The synthesis on the evolution of the geological layers, the variations of thickness and to highlight the anomalies which could affect them, the GIS tool makes it possible to draw up maps (VES) and electrical imagery (ERT ) at a depth chosen by data interpolated by Kriging. The analysis of the results shows that the Qsob zone is of paramount hydrogeological interest, it is represented by a very important layer given the great extension of the resistant formations of Plio-Plioctecene and Cretaceous age with significant thicknesses. The area is crossed by the Qsob River which is the main source of supply for these two aquifers. With the communication of the two aquifers by the very abundant and dense electric discontinuities of general directions E-W, NE-SW and NNE-SSW.