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Hydrochemical constraints between the karst Tabular Middle Atlas Causses and the Saïs basin (Morocco): implications of groundwater circulation

Journal Article · · Hydrogeology Journal
; ;  [1]; ; ;  [2]; ;  [3]
  1. CNRS-UMR 7330, CEREGE, Aix-Marseille Université, IRD (France)
  2. Université Moulay Ismail, Faculté des Sciences, Département des Sciences de la Terre (Morocco)
  3. Université d’Avignon et des Pays de Vaucluse, INRA, EMMAH, UMR 1114, LHA (France)

The karst Tabular Middle Atlas Causses reservoir is the main drinking-water supply of Fez-Meknes region (Saïs Basin) in Morocco. Recent analyses showed a decline in associated groundwater chemical quality and increased turbidity. To understand this hydrosystem, four surveys were undertaken during fall and spring, 2009–2011. Hydrogeochemical studies coupled with isotopic analyses (δ{sup 18}O, δD and {sup 222}Rn) showed that the aquifers between the causses (mountains) and the Saïs Basin are of Liassic origin and at the southern extremities are of Triassic origin. Five recharge zones of different altitudes have been defined, including two main mixing zones in the south. Deuterium excess results suggest local recharge, while a plot of δ{sup 18}O versus δD characterizes a confined aquifer in the eastern sector. {sup 222}Rn results reveal areas of rapid exchanges with an upwelling time of less than 2 weeks. A schematic conceptual model is presented to explain the groundwater circulation system and the behavior of this karst system.

OSTI ID:
22780889
Journal Information:
Hydrogeology Journal, Journal Name: Hydrogeology Journal Journal Issue: 1 Vol. 26; ISSN 1431-2174
Country of Publication:
United States
Language:
English