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Abstract

The synclinal basin of Kourimat, situated in the oriental part of Essaouira basin, shelters an aquiferous carbonate. This aquiferous represents the unique resource in water for the region.The study undertaken on this aquiferous has allowed us the characterize it viewpoint hydrodynamically, hydrogeologically and hydrogeochimically. The piezometric map of the system shows a senses of water flow underground of the southeast to the northwest. The hydraulic gradient varies from the upstream to the downstream. The evolution of the piezometry at one time watch of annual and seasonal fluctuations in connection with variations of precipitations.The results of chemical analyses have allowed to distinguish two aquiferious: the first is Cenomanian, the second is Turonian. Theses aquiferious were diffrenciated by there chemical facies and the origine of chemicals elements.Key words: Essaouira, Kourimat, Aquiferous, Cenomanian, Turonian, piezometry, hydrochemistry. RESUME La cuvette synclinale de Kourimat, située dans la partie orientale du bassin d'Essaouira, abrite un aquifere carbonaté constituant l'unique ressource en eau de la région.L' étude entreprise sur cet aquifere a permis de le caractériser de point de vue hydrodynamique, hydrogéologique et hydrogéochimique. La carte piézométrique du systeme montre un sens d'écoulement global du sud-est vers le nord-ouest. Le gradient hydraulique varie de l'amont vers l'aval. Les fluctuations piézométriques montrent une bonne corrélation avec les aléas climatiques.Les résultas de l'étude hydrochimique ont permis de mettre en évidence l'existence de deux nappes: la premiere dans le Cénomanien et l'autre dans le Turonien. Ces deux nappes se différencient par leurs facies chimiques et par l' origine des éléments en solution.

The Assessment of the Groundwater Quality in the Coastal Aquifers of the Essaouira Basin, Southwestern Morocco, Using Hydrogeochemistry and Isotopic Signatures

“…This graph is likely to illustrate how the isotopic composition of precipitation changes with altitude, which can be used to infer the altitude of the aquifer's recharge area. This approach is based on the assumption that groundwater's isotopic composition is related to precipitation at the time of recharge [84], which has a gradient of 0.25‰ per 100 m for Evaporation is a process by which water changes from a liquid to a gas, leaving behind dissolved salts and minerals. As the water evaporates, the concentration of dissolved salts and minerals in the remaining water increases, leading to mineralization.…”

“…This graph is likely to illustrate how the isotopic composition of precipitation changes with altitude, which can be used to infer the altitude of the aquifer's recharge area. This approach is based on the assumption that groundwater's isotopic composition is related to precipitation at the time of recharge [84], which has a gradient of 0.25‰ per 100 m for δ 18 O. This value is consistent with that defined for the High Atlas (0.27‰ per 100 m) [85] and that of the Essaouira Basin our study area (−0.26‰ per 100 m) [86]; the projection (Figure 16) reveals that the waters originate from altitudes between 120 (E70) and 900 m (HT117).…”

Assessment of Groundwater Quality and the Main Controls on Its Hydrochemistry in a Changing Climate in Morocco (Essaouira Basin)

“…Understanding the sources and mechanisms of groundwater recharge in the Essaouira synclinal basin, a semi-arid area in northwest Morocco, is essential for water resource management and coal mine safety [49,50]. Hydrochemical and stable hydrogen and oxygen isotopic data were used to study water-rock interactions and groundwater recharge in many regions [22,[51][52][53].…”