Geochemical assessment of groundwater in semiarid area, case study of the multilayer aquifer in Djelfa, Algeria
Salah Eddine Ali Rahmani, Brahim Chibane
Abstract
Abstract The best understanding of the geochemical process of groundwater is important for a sustainable development and for a strategic management of water resources. A hydro-geochemical study of groundwater of the Djelfa multilayer aquifers systems was established, using stable isotopes, and major elements, in order to identify the groundwater mineralization process occurring in this system. The chemical data indicate that the dissolution of evaporate minerals (Gypsum, halite, anhydrite) and the evaporation from water table are the principle processes who command the groundwater mineralization. Groundwater samples are depleted in stables isotopes ( 18 O and 2 H) reflecting a slug of water recharged during colder climatic conditions, and the recharge was occurred at different altitude. The analysis of the replenishment of aquifer levels shows that the level arises in the replenishment of aquifer and decreases in the depletion of aquifer due to the phenomena of evaporation and to the extensive pumping from wells. Excessive pumping creates a remarkable cone of depression that makes flow direction from syncline to the basin outlet.