The hydrogeology of the region is characterized by the presence of two distinct aquifer domains: the sedimentary domain, which includes the majority of the region’s groundwater, and the crystalline basement domain, which can contain limited but highly valuable water flows for supplying water to the area.
Crystalline basement domain :
This domain is composed of Precambrian or Paleozoic rocks that occupy the eastern, southeastern, and northern zones of the basin. It lacks widespread aquifers and water circulation is limited to fracture zones and riverbeds. Water is generally encountered at shallow depths with low flow rates and is of good to moderate quality.
The regions affected by this context are located in the provinces of Es Smara (Haouza, Jdiria, and Amgala), Boujdour (Gueltat Zemmour), and Aousserd (Aousserd and Tichla).
Sedimentary basin domain (Laayoune-Dakhla) :
This domain occupies the western part of the basin, along the Atlantic Ocean. It covers an area of approximately 110,000 km² on the continent and continues under the sea. It is relatively rich in widespread underground water reservoirs. The scarcity of precipitation means that the aquifers are poorly or not recharged
Isotopic analyses confirm that the majority of groundwater infiltrated more than 5,000 years ago and, therefore, these are considered fossil aquifers.
