Evolution of groundwater salinity in the unconfined aquifer of Bou-Areg, Northeastern Mediterranean coast, Morocco

• Published in: Environmental earth sciences Vol. 54; no. 3; pp. 491 - 503
• Main Authors: El Mandour, A, El Yaouti, F, Fakir, Y, Zarhloule, Y, Benavente, J
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.04.2008; Springer-Verlag; Springer; Springer Nature B.V
• Subjects: Anthropogenic factors; Aquifers; Arid climates; Bou-Areg; Chemical analysis; Climatic conditions; Coastal aquifers; Coasts; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Geochemistry; Geology; Groundwater; Groundwater salinity; Gypsum; Hydrogeology; Hydrology. Hydrogeology; Lagoon; Lagoons; Mineralogy; Miocene; Nitrate pollution; Original Article; Pollution, environment geology; Quaternary; Saline water intrusion; Salinity; Salinization; saltwater intrusion; Seawater; Semiarid climates; Silicates; Studies; Temporal distribution; Unconfined aquifer; Unconfined aquifers; Water analysis; Water geochemistry; Morocco; North Africa; Africa; ASE, Morocco; MED, Western Mediterranean; Seawater intrusion; Morocco; Groundwater salinity; Unconfined aquifer; Bou-Areg; Nitrate pollution; Lagoon; temporal distribution; fine-grained materials; ground water; sulfates; nitrates; spatial distribution; aquifers; bedrock; hydrochemistry; flow; salinity; fertilizers; salt-water intrusion; hydrodynamics; climate; silt; transmissivity; gravel; lagoons; sand; physicochemical properties; water quality; unconfined aquifers; semi-arid environment
• ISSN: 0943-0105; 1866-6280; 1432-0495; 1866-6299
• DOI: 10.1007/s00254-007-0842-3

The Bou-Areg plain in the Mediterranean coast at the North-eastern of Morocco is characterized by a semi-arid climate. The aquifer consists of two sedimentary formations of Plio-quaternary age: the upper formation of fine silts and the lower one of coarse silts with sand and gravels. The aquifer is underlain by marly bedrock of Miocene age that dips toward the coastal lagoon of Bou-Areg. The hydrodynamic characteristics vary between 10-⁴ and 10-³ m/s; and transmissivities range between 10-⁴ and 10-¹ m²/s. The general direction of flow is SW to NE, toward the lagoon. The aquifer is crossed by the river Selouane, which also ends in the lagoon. The groundwater is characterized by a high salinity that can reach 7.5 g/l. The highest values are observed in the upstream and in the downstream sectors of the aquifer. The temporal evolution of the physico-chemical parameters depends on the climatic conditions and piezometric variations. The analysis of the spatio-temporal distribution of the physico-chemical parameters suggests different sources of groundwater salinization: the seawater intrusion, the influence of marly gypsum-bearing terrains, and the influence of anthropogenic products as the agricultural fertilizers, which cause great nitrate concentrations that vary between 80 and 140 mg/l.