Integrated evaluation of irrigation suitability of groundwater in El Oued (SE Algeria) using graphical analyses and the irrigation Water Quality Index (IWQI)

Integrated Evaluation of Irrigation Suitability of Groundwater in El Oued region (SE Algeria). Groundwater is essential for agriculture in arid regions but is increasingly affected by salinization and human activities. This study assessed the hydrochemical characteristics and irrigation suitability of groundwater from the phreatic aquifer of El-Oued, southeastern Algeria. Fourteen samples collected in April 2024 were analyzed for 15 physicochemical parameters. Irrigation suitability was evaluated using IWQI, Na%, SAR, SSP, KI, and PI, while PCA identified the main controls on groundwater chemistry. Results showed highly mineralized water dominated by Cl− and SO42− among anions and Na+ and Ca²+ among cations, reflecting evaporation, water–rock interactions, and ion exchange. Mean values of IWQI, Na%, SAR, SSP, KI, and PI were 34.62, 43.33%, 7.45, 42.42%, 0.79, and 32.17%, respectively. Approximately 79% of samples exhibited severe irrigation restrictions. PCA indicated that salinity, sodium enrichment, and anthropogenic contamination were the main factors controlling groundwater quality. Continuous monitoring and sustainable groundwater management are therefore essential to protect agricultural water resources in El-Oued.