ABSTRACT
The oasis of Béni Abbès has a large groundwater resource potential. There are four aquifers, the Great Western Erg being the largest, which are in hydraulic continuity to form a single complex aquifer system. Each aquifer has its own discrete properties. The Great Western Erg offers goodquality water and represents the principal resource in the aquifer system; it supplies both drinking water and half as much again for irrigation of the palm field area (40 ha of agricultural land). The supply is drawn from the spring of Sidi Othmane. The alluvial terraces are formed of sand and gravel (alluvial deposits) in the Saoura Valley and form a superficial aquifer. The aquifer at Hamada of Guir has a moderate potential. Finally the Palaeozoic aquifer is probably multi-layered. The piezometry shows a general flow direction from east to west. The Saoura Valley, formerly very active, currently receives very little recharge due to the construction of the Djorf Torba dam on Wadi Guir. The wells that withdraw water from the alluvial deposits inhibit the natural communication between the Great Western Erg aquifer and the alluvial terraces, and accelerate the arrival of saline water. Salinity increasingly invades the alluvial deposits causing serious problems for irrigation. A good knowledge of the aquifer system is necessary to safeguard the water resources and to recommend appropriate management practices.
