Comprehensive hydrogeochemical and statistical assessment of groundwater quality for drinking and irrigation in the Demie River catchment, Southern Ethiopia

This study evaluates the groundwater quality in the Demie River catchment in Southern Ethiopia, highlighting its critical role in addressing the region's growing water demands for drinking and irrigation purposes. A total of 40 groundwater samples from wells and springs were analyzed for 17 physicochemical parameters. The results showed that the WQI values ranged from 18.22 to 66.52, classifying 87.5% of the water samples as excellent and 12.5% as good for drinking. Hierarchical cluster analysis grouped the groundwater samples into three clusters, with Cluster 3, comprising most springs and shallow wells, displaying lower total dissolved solids (TDS) and electrical conductivity (EC), indicating less mineralized water. The irrigation indices confirmed that most samples were suitable for agricultural use, with low salinity and sodicity risks. The dominant water types identified were Ca–HCO₃, Ca-Na-HCO₃, and Na-HCO₃, showing progressive mineralization along groundwater flow paths. These findings provide baseline data for sustainable water resource management and emphasize the need for long-term monitoring to address anthropogenic and climate-related impacts on groundwater quality and recharge.