Application of GIS for assessing the vulnerability of aquifers to pollution in the coastal zone of Essaouira, Morocco

Z Ouzerbane; S Loulida; M Boughalem; A El Hmaidi; A Essahlaoui; A Najine

doi:10.1007/s10661-021-09673-z

Application of GIS for assessing the vulnerability of aquifers to pollution in the coastal zone of Essaouira, Morocco

Environ Monit Assess. 2021 Dec 21;194(1):35. doi: 10.1007/s10661-021-09673-z.

Authors

Z Ouzerbane¹, S Loulida², M Boughalem³, A El Hmaidi⁴, A Essahlaoui⁴, A Najine⁵

Affiliations

¹ Department of Geology, Faculty of Science, Water Science and Environmental Engineering Team, Moulay Ismail University, BP 11201, Zitoune, Meknes, Morocco. ouzerbanegeophy@gmail.com.
² Laboratory of Water, Biodiversity and Climate Change, Department of Biology, Faculty of Science, Cadi Ayyad University, P.O. Box 2390, 40000, Semlalia, Morocco.
³ Laboratory of Applied Hydrology, Environment/DGRSDT, Ctr Univ Ain Temouchent, BP 284, 46000, Ain Temouchent, Algeria.
⁴ Department of Geology, Faculty of Science, Water Science and Environmental Engineering Team, Moulay Ismail University, BP 11201, Zitoune, Meknes, Morocco.
⁵ Department of Earth Sciences, Faculty of Science and Technology, Sultan Moulay Slimane University, BP 523 Mghila, 23000, Beni Mellal, Morocco.

PMID: 34932146
DOI: 10.1007/s10661-021-09673-z

Abstract

Groundwater remains the main water resource for consumption of potable water, irrigation in the agricultural field, and for the use in industrial and touristic domains by inhabitants of cities and villages in the coastal areas with arid and semi-arid climate. In order to protect the groundwater table of the coastal zone of Essaouira, located in the west central part of Morocco, a study of the intrinsic vulnerability to pollution was tackled by the use of the Geographic Information Systems (GIS) from the DRASTIC method. This tool serve to highlight the overexploitation problems and water quality degradation and help decision makers to take good decisions to solve them. Vulnerability cards are fundamental documents for spatial planning. They represent excellent support for the establishment of all kinds of human activities taking into account the pollution of underground waters. The analysis of the vulnerability map for the pollution of the Plio-Pleistocene aquifer of the coastal zone of Essaouira, shows a heterogeneous variation in vulnerability across the area. With values of the DRASTIC index (ID) range from 45 to 149 spatially distributed in the study area, the vulnerability map established shows four (04) vulnerability classes: low (45-77), medium (78-92), high (93-112), and very high (113-149). Analysis of this map shows a dominance of low and medium vulnerability zones in most of the water table, with the percentage of each class is as follows: low (18%), medium (53%), high (22%), and very high (7%); this vulnerability to pollution calculated by the standard DRASTIC method is essentially dependent on the depth of the groundwater table and the unsaturated zone. These two parameters have a very important influence compared to other parameters that make up this method. The most dominant class is the low and middle class (71%), which represents almost the entire plain and corresponds to uncertain hydrogeological protection of groundwater by considering the hydrogeological vulnerability scale as certainly well protected.

Keywords: DRASTIC method; Essaouira; GIS; Pollution; Vulnerability; Water quality.

MeSH terms

Environmental Monitoring
Geographic Information Systems*
Groundwater*
Morocco
Water Pollution* / analysis
Water Supply