Groundwater geochemical modeling under severe climate conditions for sustainable agricultural development, the case of Chougafiya Basin, central Tunisia

Monitoring groundwater quality (GWQ) is vital for water sustainability, mainly in arid to semi-arid regions with intense agriculture and inadequate irrigation management systems. It was, closely, linked to groundwater hydrochemistry (GWH). The present work aims to identify factors controlling this in the Chougafiya shallow aquifer (Central Tunisia), which is known for groundwater hypersalinization and intensive agricultural activities under severe climate conditions. Based on 30 inventoried wells data, the proposed approach combines (i) exploratory factor analysis and (ii) confirmatory factor analysis as a structural equation model (SEM) to detect the most relevant factors involved in GWH and their spatial variability. It has been demonstrated that GWH was governed by Na-Cl and Ca-SO4 type, resulting from evaporated minerals (halite and gypsum). The results showed a total explained variance of 86% and allowed the identification of two main factors that control groundwater salinization: (1) the natural factor, mainly, attributed to the water-rock interactions and (2) the anthropogenic factor, mainly related to anarchic farming practices. As a confirmatory analysis, the development of SEM led to the identification of the most important factors that control water mineralization. These results could be helpful for the strategic plans for water resources management in the studied area.