Groundwater Protection Using DRASTIC Vulnerability Maps and ArcFem Tools for Perimeter Protection: A Case Study in the Charf El Akab Aquifer (Morocco North)

Abstract

The Charf El Akab aquifer has a surface area of 17 km 2 and is located about 20 km southwest of the Tangier city, it circulates in the Miocene sandy basin of the same name and comprises two layers, one high and the other low, these two are separated in some places by an airtight impenetrable sand-marly formation. The requirements for water whether potable or industrial, in the Tangier-Asilah region are expected to amplify in order to support the increasing demand prompted by the economical development, population growth as well as the heightened threat of scarcity related to climate change. Currently, the water supply of this region is ensured mostly by the two dams: Ibn Battouta and “April 9, 1947”. However, this aquifer plays the role of an easily usable emergency reservoir, in case of an extra water supply in rush hour or in the event where current service works of the cities of Tangier and Asilah are unavailable. Nevertheless, water resources are still vulnerable because of the existence of abandoned quarries in the area. Therefore, the protection of this aquifer against any source of pollution is the purpose of this work. The lower water layer is the only one that can be exploited by the ONEE (National Office for Electricity and Drinking Water), due to the fact that it has a better quality and very good hydrodynamic characteristics. The most important thing about this work is the establishment of an intrinsic vulnerability map to the pollution by the DRASTIC method, by exploiting of the calibrated hydrodynamical model results. In the same context of protection, a guesstimate of the close protection perimeter of 72.76 ha was acquired, using a new numerical modeling approach by the “Arcfem” software under the ArcMap environment.