Contribution of Geophysics to the Management of Water Resources: Case of the Ariana Agricultural Sector (Eastern Mejerda Basin,Tunisia)

In Tunisia, the Mejerda basin is the most important agricultural sector. Identification of additional water sources and good management of current and new resources is required to maintain and increase its productivity. The present study concerns the Ariana region (north-east of Tunisia) covering the eastern part of Mejerda basin. Lithological columns, well logs, vertical electrical soundings, and gravity data were analyzed and interpreted to give more precise information for exploitation of the water resources of the Ariana region. Lithological columns, well logs, and geoelectrical models reveal that the permeable Quaternary alluvial deposits, the Upper Campanian–Lower Maestrichtian, Albian and Barremian limestones, and Valanginian–Hauterivian sandstones are the main aquifers in Ariana. Comparison of geoelectrical cross sections to the Bouguer anomaly map of the Ariana region reveals tectonic influence on the geometry of the aquifers. The folded structures attributed to the Tortonian compressive stress and the tectonic movements in N–S, E–W, NW–SE, and NE–SW directions have resulted in the compartmentalization of Ariana’s aquifers into subsided and raised blocks. This reconstituted geometry of the region influenced the depth of burial of permeable lithologies and inhibited groundwater circulation in some localities.