## 4 Conclusions  
The Mornag aquifer groundwaters flow in the South-North, Northeast-Northwest, and Southwest-Northeast directions, indicating that recharge occurs in the foothills of Khledia, Djebel Et Tella, Er Rorouf, and Rades, while discharge occurs in the Gulf of Tunis. Recharge can be accomplished by either direct infiltration of rainwater or by linear infiltration along the beds of the wadis El Hma and Meliane.  
Geochemical analysis, multivariate statistics, and water quality indices were used in the spatial-temporal evaluation of groundwater quality, identifying the main mineralization processes and determining its suitability for drinking and crop irrigation. It was revealed that groundwater quality depends largely on the geographic location and geological context of the study area. Two water facies were identified, namely, chloride-sodium-potassium and chloride-sulfate-calcium and magnesium facies, suggesting an increase in total salinity in the direction of groundwater flow. According to the calculation of saturation indices, Mornag groundwater is oversaturated with respect to carbonated minerals but undersaturated with respect to evaporative minerals.  
Major ion concentrations, which increase in the direction of groundwater flow, show that water-rock interactions, wastewater recharge drained by wadi Meliane, and the return flow of irrigation water constitute the main hydrogeochemical processes controlling the composition of Mornag groundwater. The water quality indices show that all groundwater samples are classified as poor to unsuitable for drinking purposes. Furthermore, the majority of Mornag groundwater samples are not suitable for the irrigation of most soil types. In fact, SAR and EC values exhibit that high salt and sodium in the Mornag shallow groundwater may pose challenges to groundwater irrigation in the study area. Anthropogenic waste and agricultural fertilizers will continue to contaminate groundwater, leading to a deterioration in water quality. In a scenario where the quality of groundwater remains variable in time and space, a loss of cultivated soil and a decrease in agricultural production will be expected, resulting in a significant economic loss. Furthermore, intensifying climate change, marked by dry conditions, will make surface water scarce, leading to the use of groundwater for drinking water supply and irrigation. This will lead to a long-term deterioration in groundwater and soil quality and, as a result, a loss of crop yield.  
E.H., conceptualization, formal analysis, data curation, writing--original draft preparation, and writing--review and editing; A.B.M., formal analysis, writing--review and editing, and supervision; M.P., formal analysis and supervision; A.M. formal analysis and supervision. All authors have read and agreed to the published version of this manuscript.  
Earth Sciences PhD program at Sapienza University.  
Not applicable.  
**Data Availability Statement:** \"MDPI Research Data Policies\" at [[https://www.mdpi.com/ethics](https://www.mdpi.com/ethics)]([https://www.mdpi.com/ethics](https://www.mdpi.com/ethics)) accessed on 26 July 2023.  
This work has benefited from discussions with [PERSON]. The authors would like to thank him for his scientific cooperation. The authors thank the anonymous reviewers who significantly improved this paper with their valuable comments.  
The authors declare no conflict of interest.