Geophysical Contributions to Hydrogeological Study in the Chemtou–Sidi Miskine Agricultural Sector (Northwestern Tunisia)

This study presents an example of the use of geophysics for agricultural water management. Borehole data, gravity measurements and vertical electrical soundings were used to reconstruct a precise hydrogeological scheme of the Chemtou–Sidi Meskine area (Northwest of Tunisia) in order to assist exploitation and judicious management of the underground water resources for irrigation. The Chemtou–Sidi Meskine area belongs to Mejerda basin, the most important agricultural sector in Tunisia. It is characterized by the coexistence of alluvial and basement aquifers, which are very scare in this country. The computed gravity maps emphasize an E–W lineament separating Hairech metamorphic formations and Mejerda alluvial deposits. The apparent resistivity maps confirm the presence of this lineament. The interpreted vertical electrical soundings are correlated with lithological columns to give more accurate structural patterns. The resulting geoelectrical cross sections highlight a normal fault network that collapsed metamorphic aquifers, controlled the Quaternary alluvial aquifers thickness and created closed areas with high water salinity that is unfavorable for exploitation.