Hydro-chemical characterization and geospatial analysis of groundwater for drinking and agricultural usage in Nashik district in Maharashtra, India

Groundwater qualities in Nashik District of Maharashtra were analyzed using hydro-geochemical characterization and geospatial techniques for sixty-one (n = 61) representative samples. GIS-based WQI was computed for planning and monitoring the groundwater qualities in the study region. Piper trilinear and Gibbs diagram were plotted to determine the variation in hydro-geochemical facies and to understand the functional sources of chemical constituents. The analytical results cleared that the nature of the groundwater is highly alkaline. Majority of the samples were within the desirable and maximum permissible limits as decided by Bureau of Indian Standards for each parameter. Piper diagram shows about 39.34% samples belong to Ca2+–Mg2+–Cl−– $${\text{SO}}_{4}^{2 - }$$ SO 4 2 - type, signifying permanent hardness and 57.37% samples belong to Ca2+–Mg2+– $${\text{HCO}}_{3}^{ - }$$ HCO 3 - type suggesting temporary hardness. Only 3.25% samples fall under Na+–K+–Cl−– $${\text{SO}}_{4}^{2 - }$$ SO 4 2 - type. Alkaline earth exceeds alkalis in 96.72% samples of the groundwater. The WQI suggests that 59% sites have excellent and good quality water; and about 41% sites characterized by poor quality water, which are unsuitable for drinking purposes. WQI values for TDS, TH, Ca2+, Na+, Mg2+, Cl−, K+, $${\text{NO}}_{3}^{ - }$$ NO 3 - and $${\text{SO}}_{4}^{2 - }$$ SO 4 2 - are more than the permissible limits. Hierarchical cluster analysis corroborates the spatial analysis results of WQI and proved statistically. The present investigation indicates significant dominance of agriculture and rock weathering that influence the groundwater chemistry in Nashik district.