Mapping recharge potential zones and natural recharge calculation: study case in Sfax region

The groundwater constitutes the major water resource in the study area of the current paper that is Sfax region. The latter is located in the south of Tunisia where the climate is arid. In fact, the natural groundwater recharge of the region is deeply affected by the lack of precipitations which affects its natural groundwater recharge. The aim of the current paper is to define recharge potential zones and to estimate the rainfall recharge of the shallow groundwater. Henceforth, the potential recharge map was established, based on the basin characteristics using lithology, topography, slope, and stream network parameters. Recharge estimations were based on the numerical methods: the Estimation of Recharge in Overexploited Aquifers (Estimación de la Recarga en Acuíferos Sobreexplotados) (ERAS) numerical model, the Schoeller equation, the Fersi equations, and the Direction Générale des Ressources en Eaux (General Administration of Water resources) (DGRE) coefficients. As a matter of fact, applying the Fersi equations and the DGRE coefficients on the potential zones allowed the deduction of a new spatial repartition of both favorable and unfavorable recharge zones.