Despite numerous groundwater studies in semi-arid regions of India, there is a lack of integrated approaches combining hydrogeochemical analysis with GIS-based modeling and multivariate statistics at the district scale, particularly in the Nashik region. This study aims to evaluate groundwater quality, identify controlling hydrogeochemical processes, and assess its suitability for drinking and irrigation. A total of 170 representative groundwater samples were analysed for physicochemical parameters. GIS-based Water Quality Index (WQI) mapping and multivariate statistical techniques, including Principal Component Analysis (PCA), were applied. Hydrogeochemical facies and controlling mechanisms were interpreted using Piper, Gibbs, and Wilcox diagrams. The results indicated predominantly alkaline nature of groundwater, with most samples falling within the Bureau of Indian Standards’ permissible limits. Approximately 60.6% of samples were classified as Ca 2+ –Mg 2+ –HCO 3 − type, indicating temporary hardness, while 35% represented Ca 2+ –Mg 2+ –Cl − –SO 4 2− type (permanent hardness), and 2.35% corresponded to Na + –K + –Cl − –SO 4 2− type. The GIS-based WQI revealed that about 80% of the sampling sites possess excellent to good water quality, whereas 20% exhibit poor quality unsuitable for drinking. Wilcox analysis demonstrated that 88% of samples are suitable for irrigation, with 12% showing elevated sodium risk. PCA results identified hardness (PC1: 53.17%), agricultural nitrate contamination (PC2: 15.68%), and localized fluoride enrichment (PC3: 9.71%), as the primary determinants of spatial heterogeneity. The integrated GIS-PCA approach provides a comprehensive understanding of groundwater quality and its controlling processes. The results support groundwater management and agricultural planning by helping prioritize areas for monitoring and sustainable water use. • Groundwater in Nashik district predominantly exhibits high alkalinity, with 60.59% samples indicating temporary hardness (Ca 2+ –Mg 2+ –HCO 3 − type) and 35% showing permanent hardness (Ca 2+ –Mg 2+ –Cl − –SO 4 2− type). • GIS-based WQI revealed 80% of groundwater samples are of excellent or good quality, while 20% are unsuitable for drinking. • Wilcox analysis classified 88% of groundwater samples as suitable for irrigation; 12% are at risk due to high sodium levels. • PCA identified hardness (53.17%), agricultural nitrate contamination (15.68%), and localized fluoride (9.71%) as primary drivers of groundwater quality variability.
Aware et al. (Fri,) studied this question.