Spatial assessment of groundwater quality using water quality index and hydrochemical indices in the Kodavanar sub-basin, Tamil Nadu, India

The purpose of this study was to assess the drinking and irrigation groundwater quality in Kodavanar sub-basin, Dindigul and Karur region, Tamil Nadu, India. Water samples were measured according to the geological and hydrogeological aspects. Geographically, the study area is situated in 10°11′37″–10°27′30″N and 77°37′46″–78°01′10″E with an entire area of 2255 km2. Overall, 82 groundwater samples were taken from bore wells and various physicochemical parameters and major ion chemistry like pH, electrical conductivity, total dissolved solids, calcium, magnesium, sodium, potassium, bicarbonate, chloride, sulfate, nitrate, and phosphate were analyzed. According to the groundwater quality, Gibbs, United States Salinity Laboratory and Wilcox’s diagrams were plotted; and groundwater quality has been illustrated for domestic and agricultural purposes. Gibbs plot results showed that 87% of the sample falls under the rock dominance. Sodium absorption ratio 100%, sodium percentage 85%, and Kelly’s ratio 51% recommends that majority of the sample falls under the acceptable border of irrigation and drinking utility. Using geospatial analysis, the water-quality index was calculated. The result shows that most of the area comes under excellent (402 km2) and good (1297 km2) groundwater categories. Based on the studies, the quality of groundwater is safe for drinking purposes, but in a limited sample, which exceed the limit, due to anthropogenic activities. © 2017, Springer International Publishing AG.