Faced with the challenges of sustainable groundwater resource management in the arid zone, the identification of re-serves and their monitoring have become vital. This paper aims to identify the Turonian aquifer in the Cretaceous Béchar basin, and calculate its transmissivity, permeability and storage coefficient, as well as its evolution over time. This Tu-ronian aquifer is characterized by marine limestones (gentle dip shelters 45° to the North and 5° to 10° to the South). Pumping tests revealed a transmissivity T of 10–4 to 10–2 m2·s–1, a permeability K of 10–6 to 10–4 m·s–1 and a storage coeffi-cient S of approximately 10–3. Two piezometric campaigns, carried out between (1976–2018), show a converging and con-stant flow direction from the North–East to the South–West and from the North–West to the South–East towards the outlet of the basin. Decreased values were observed in the North and South–West borders due to isopiezometric lines. However, this water table is not in a stationary state, it shows seasonal and interannual fluctuations in relation to the variable rainfall and the exploitation rate. In terms of facies, the projection of the two hydrochemical campaigns, during 1976 and 2018 on the Piper diagram, did not show any significant evolution, they are concentrated in the chlorinated and sulphated calcium and magnesium facies.

The aquifers in the M’léta Plain are crucial for supplying drinking water and supporting industrial and agricultural water needs. However, they are facing a pollution risk and environmental degradation. The present study aims to assess the groundwater quality in the M’léta Plain, focusing on its physicochemical properties, statistics of the aquifer, pollution risks, and factors influencing the water mineralisation process. The analysis of 16 samples reveals that the water contains high levels of sulphates and chlorides, often accompanied by sodium, calcium, or magnesium. This suggests two distinct water types or facies: one characterised by sodium chloride or calcium chloride, and the other with calcic or sodic sulphate waters, sometimes including magnesium sulphate. These facies may be attributed to the influence of different formations at the outcrop. Statistical analyses reveal a strong correlation between electrical conductivity and the majority of chemical elements, indicating the impact of freshwater interacting with the underlying rock formations on mineralisation. Some results also show undersaturation of certain minerals. Furthermore, the study evaluates the water's suitability for irrigation in the M’léta Plain in accordance with Richards’ classification.