Potential Hydrogeological, Environment and Vulnerability to Pollution of the Plio-Quaternary Aquifers of the Coastal Basin of Essaouira (Morocco)

Abstract

The Essaouira synclinal area is part of the semi-arid areas of Morocco which are subject to the impacts of climate and anthropogenic pressures. It is also expected to experience an important agro-industrial development. Water requirements are important for the development of all these activities. Although the situation is not yet alarming, the fact remains that the quality of groundwater resources is constantly put to the test because of the growth sources as diffuse pollution that point. To prevent pollution of groundwater, one approach is the knowledge of especially vulnerable areas. It is for this reason that this study was initiated to produce a map of intrinsic vulnerability of aquifers in the region. The method used to make the card is the numerical rating DRASTIC method (Aller et al. 1987). In the case of this coastal area, which includes two main aquifers superimposed; the Plio-Quaternary and Turonian, the resulting vulnerability is compounded by the risk of infiltration navy. The Rainfall in the area does not exceed 300 mm year-1, the average temperature hovers around 20 ° C. The results indicate that the region is dominated by the class of high vulnerability (61%) followed by the class of very high vulnerability (20%), then the class medium vulnerability (15%) and the class of low vulnerability (4 %). Class very high vulnerability is located in the western coastal area. The center of the basin is dominated by the class of high vulnerability to the east, past the middle and low class. Almost throughout the Oued Ksob is particularly dominated by the class of high vulnerability.

Keywords: basin of Essaouira; aquifer; semi-arid regions; hydro geochemistry;  stable isotopes; recharge; vulnerability, pollution, DRASTIC, management, protection of water resources