Appraisal of groundwater quality in upper Manimuktha sub basin, Vellar river, Tamil Nadu, India by using Water Quality Index (WQI) and multivariate statistical techniques

Groundwater is a major natural resource for drinking and irrigation purpose. The overexploited of groundwater is increase year by year and quality of groundwater simultaneously decreases. Groundwater quality is the main issue because water is linked with our metabolism. In order to know the groundwater pollution and controlling factors of groundwater quality in the upper Manimuktha sub basin, Vellar river, Tamil Nadu, India. Forty eight groundwater samples were collected from entire study area on January 2014 and analysed for physicochemical properties. Major ions were as abundance of Na > Ca > Mg > K, and HCO3 > Cl > SO4 > NO3 respectively. Multivariate statistical analyses display the good correlation between all the physicochemical parameters except pH and F. The dendrogram reveals cluster 3 (EC and TDS), cluster 2 (alkalinity, TH, HCO3) and cluster 1 (F, K, NO3, Ca, Mg, Na, SO4, Cl). The hydrochemical processes reveal rock-weathering interactions and ion-exchange processes play an important role in groundwater quality of the study area. The WQI indicates 50.03% of the samples fall in excellent to good for drinking in the center of the study area. Remaining samples fall poor to very poor categories, signifying northern and southern side mainly polluted. Maximum of lakes located in the northern side also indicate poor quality, because of the contamination of wastewater at or near the lakes, migrate in the groundwater. This study has shown the great combination of GIS, statistical analysis and WQI in assessing groundwater quality give a clear view for decision makers can plan better for the operation and maintenance of groundwater resources.