Assessing and delineation of groundwater recharge areas in coastal arid area southern Tunisia

In Gabès region (southeastern Tunisia), given the semi-arid to arid climate conditions, groundwater is an essential resource to supply the growth needs of the socio-economic development. To ensure sustainable development and preserve water resources, a careful estimation of the present day recharge amount and the delineation of the potential zones of rainfall precipitation are of required for an accurate evaluation of regional water balance. In this context, this study aims to a preliminary assessment of groundwater recharge in Gabes basin in regard to the delineation of the potential recharge areas of phreatic aquifers. Thus, a geological and hydrogeological collected database coupled with remote sensing techniques (RST) were used for the determination of the lateral variation of recharging zone, Treatment by ArcGIS and Matlab softwares and Kohonen self-organizing maps (K-SOM) approaches. The obtained results indicate that five recharge potential areas have been identified and classified as 27% very low, 23% low, 40% moderate recharge, 7% good and 3% very good potential recharge located principally on southern part of the study region. This distribution is controlled principally by the geomorphological, geologic, and hydrogeologic features of the region. Reasonable management strategies based on a perennial exploitation of these low renewable resources are required to optimize the water dependent socio-economic development. The estimated groundwater potential recharge of Gabès aquifer system using K-SOM and RST is of 11.4 Mm³ y⁻¹. This recharging rate is very low it present 7% of the total rain, thus it must be ameliorated. K-SOM and RST approach is a useful method for groundwater potential recharge mapping and is a helpful of wells establishment and groundwater sustainable management. an isotopic analyses is recommended to ameliorate the decision maker to establish the adequate strategy.