Hydrogeological and Hydrochemical Characterization of Mejel Bel Abbes Aquifer (West-Central Tunisia)

The Mejel Bel Abbes region (west-central Tunisia) constitutes a subsiding lowland filled with Plio-Quaternary deposits. These deposits contain shallow aquifer exploited for agricultural and drinking water purposes. A good management of these groundwater resources requires recognizing their hydrodynamics and their chemical processes. The piezometric map shows that groundwater flows from north to south toward the Gafsa North plain. The piezometric profile demonstrates that the piezometric level is related to the topography of the terrain. Miocene sands and Plio-Quaternary aquifers form together a single free hydrogeological unit. Chemical analyses revealed that groundwater within this hydrogeological unit is rich in sulphates and chlorides. The total mineralization of analysed samples highlights a good chemical quality that remains almost uniform over the entire Mejel Bel Abbes region. The Plio-Quaternary aquifer, however, yields groundwater supersaturated with carbonate minerals and saturated with halite and gypsum.