This work aims to identify the potential groundwater recharge zones in the Mitidja plain (north Algeria) using the multi-criteria approach. The analysis was based on the use of a geographical information system (GIS) and remote sensing to establish eight thematic maps, weighted, categorized and inserted, that allowed us to establish the potential zones’ map for groundwater recharge. Three potential groundwater recharge classes were defined corresponding, respectively, to low (26%), moderate (47%) and high (27%). The best groundwater potential zones are situated in the piedmont of the Blidean Atlas (the south of the study area), precisely, upstream near to wadis (wadi El Harrach, wadi Djemaa, wadi Mazafran) and the western aquifer limit, where the hydrogeological units are formed by the alluvium formation which is characterized by high hydraulic conductivity, high water flow, low slope, low drainage, low quantity transported sediments and good water quality. The obtained results, in this work, describe the groundwater recharge potential areas and supply information for a suitable mapping and the management of aquifer resources in the study area.

The Korba region in northwestern Tunisia has a coastal aquifer that is impacted by intensive irrigation, urban expansion, and sensitivity to SWI. We assessed the vulnerability extent of Korba’s GW to SWI. We utilized a parametric model for GW vulnerability assessment, the GALDIT, which considers six parameters to determine SWI effects. The GALDIT map has four rating categories (≥7.5, 7.5–5, 5–2.5, and <2.5), representing very high, high, moderate, and low vulnerability, respectively. Most of the region was found to be highly vulnerable (44.2% of the surface area), followed by areas characterized by very high (20.3%) and moderate (19.3%) vulnerability. Only 16.2% was found to have low vulnerability. A parameter sensitivity analysis showed that distance from shore and depth of GW represent the determining factors for SWI with variation index values of 24.12 and 18.02%, respectively. Inland advancement of seawater is causing GW salinity to rise, as indicated by a strong Pearson correlation coefficient of 0.75 between SWI indices and the electrical conductivity. Suitable areas for artificial recharge were mainly distributed in the alluvial plains, with a total area of 32.85 km². Inhibiting SWI requires about 11.31 MCM of artificial recharge in the two most suitable recharge zones in the region.

The Mitidja plain area, located in north Algeria, is one of the main agricultural plains in the Mediterranean basin where water supplies are mainly provided by groundwater resource. Due to the effects of a rapid population increase, followed by an intensification of agricultural activities, a proper groundwater vulnerability assessment became urgent. In this study, the DRASTIC model has been utilized to produce a map of groundwater vulnerability for nitrate pollution. To improve the standard DRASTIC vulnerability map, and to offer an innovative and easy tools for water resource protection and water forensics, the rating classes of the DRASTIC model was modified using the real nitrate concentrations analyzed in 44 groundwater sample while sensitivity analysis was used to change the parameter’s weights. The validation of the standard DRASTIC model shows a coincidence rate of 67% while the validation of the modified DRASTIC model shows a coincidence rate of 82% (improvement of 15%) with nitrates. The results highlighted two main findings: i) the reliability of modified DRASTIC model, and ii) the dependence of nitrate vulnerability on net recharge, aquifer type, soil texture and topography. The proposed approach demonstrated to be more appropriate in assessing the groundwater vulnerability compared to standard DRASTIC proving to be easy applicable and suitable in any arid and semi-arid region around the world.