The increase in salinity is one of the most conspicuous phenomena that affect the water quality in Morsott-El Aouinet area (North East of Algeria). Future exploitation and management of the water resources under these conditions will require a deep understanding of the sources and mechanisms of contamination. The studied area is located within the arid zones of Algeria, situated fifty kilometres far from Tebessa city and is characterised by a precipitation of less than 400 mm per year. It extends from El Aouinet in the north, to Morsott to the south, for about 180 km². This aquifer plays a very important role in providing drinking water for the local population. Overexploitation of this resource has caused a progressive degradation of the water quality in the irrigated area resulting in high salinity zones.
In this paper groundwater hydrochemistries are studied through well sampling from the study area, showed extremely high concentrations of salts, ranging from 1154 to 23800 µScm-1, decreasing from South towards North, far exceeding the acceptable limit for various purposes as given in Algerian Water Quality Guideline. Hydrochemical end products were identified and the sources of water salinization defined. It was found that the evaporites within the Triassic rocks are the main contributors to the salinization of groundwater. From the hydrochemical evaluation of the analyses results, two different water types could be identified:
The results obtained with stable isotopes (oxygen 18 and deuterium) broadened and strengthened our knowledge about conditions and recharge areas of the Plio-Quaternary aquifer.The isotopic study shows that this aquiferous receives a refill from efficient rainfall without a high evaporation.