This work was conducted on 23 samples distributed between springs, wells and boreholes tapping the shal-low and deep aquifer in the M’Daourouch-Drea area located in extreme northeast of Algeria. Ca2+, Mg2+, Na+, K+, Cl–, SO42–, HCO3– and NO3– were analysed. The interpretation of the geological-geophysical data allowed us to highlight two aquifers. The first consists of conglomerates, sandstones, gravels, sands, marls, limestones, la-custrine and alluvial deposits varying in thickness from a few tens to a few hundred meters, representing Neo-gene-Quaternary filling of the studied basin. The second is more important localized in the cracked and karstified limestones of upper Cretaceous age; these limestones are outcropped on the flanks of the syncline and the bor-ders of the basin. The first aquifer sometimes rests directly on the second which allows hydraulic communication between them. The hydogeochemical and statistical study, with the combination of numerous tools, indicates that the chemistry of groundwater in the M’Daourouch-Drea Plain is controlled both by the dissolution of the miner-als of the evaporite formations and those of the carbonate formations.

This paper was made in the region of M’daourouch-Dréa which is part of the high plains of northeastern Algeria, located southwest of the Souk-ahras Wilaya in eastern Algeria. It is a plain with agricultural vocation which requires for its development more water. Knowing that the rainfall is low (465mm/year) and not enough to meet the needs of farmers, the use of groundwater then becomes the only alternative to fill this lack of resources. Among the aquifers identified in this region is that contained in fissured limestones of lower Maestrichian age. In order to satisfy farmers and citizens in water it is necessary to have a good characterization of this aquifer. The objective of this paper is to improve the knowledge on the morphology and the extension of this aquifer and to locate its roof in space to help operators choose areas favorable to exploitation, so direct them to the nearest areas of the surface thus minimizing the cost of the drilling operation. To achieve this goal, we have exploited by exploiting several tools (geological map, logs of boreholes and geophysics survey), whose combination gave an idea on the geometry of the aquifer as well as the depth of its roof in different regions of the plain and shows by the occasion, the affectation of these limestones by several tectonic accidents generating thus a structure in collapsed blocks from where the very variable depth of the roof of these limestones of a place of the plain to other.

This paper was made in the region of M’daourouch-Dréa which is part of the high plains of northeastern Algeria, located southwest of the Souk-ahras Wilaya in eastern Algeria. It is a plain with agricultural vocation which requires for its development more water. Knowing that the rainfall is low (465mm/year) and not enough to meet the needs of farmers, the use of groundwater then becomes the only alternative to fill this lack of resources. Among the aquifers identified in this region is that contained in fissured limestones of lower Maestrichian age. In order to satisfy farmers and citizens in water it is necessary to have a good characterization of this aquifer. The objective of this paper is to improve the knowledge on the morphology and the extension of this aquifer and to locate its roof in space to help operators choose areas favorable to exploitation, so direct them to the nearest areas of the surface thus minimizing the cost of the drilling operation. To achieve this goal, we have exploited by exploiting several tools (geological map, logs of boreholes and geophysics survey), whose combination gave an idea on the geometry of the aquifer as well as the depth of its roof in different regions of the plain and shows by the occasion, the affectation of these limestones by several tectonic accidents generating thus a structure in collapsed blocks from where the very variable depth of the roof of these limestones of a place of the plain to other.