Relation barrage-nappes.

Abstract

The Beni Haroun dam is situated into an area characterised by a high potentialities of surface water (Oued Rhumel, Oued Endja….), and ground water (karstic aquifer, alluvial aquifer of Oued Endja…). The study target consists of the region hydro systems knowledge and the evaluation of the dam water impact on the ground water resources. The result of the piezometric level monitoring of the dam piezometers reveal the infiltration of dam water towards the karst representing the seat of the dike. The water flow is concentrated in left bank following two drainage axes: the contact between the limestone and the Paleocene marl in the NW part and the discontinuities network of breach and fracture. The last dry years have allowed the filling of the dam and also the increasing of the piezometric level of the aquifers located directly below the dam and the inferoflux of Oued Endja. The chemical study of water has shown a facies influenced by the carbonated formations (calcic carbonated facies) and also the Triassic ones (sulfat facies), water chemistry evolution shows the effect of water dam on ground water after the filling and overflowing of water.