Identification of the Factors Governing Quality of Groundwater in Hard Rock Region using multivariate and Spatial analysis

The rapid increase in the groundwater users and gradual variations in the hydrological cycle due to climate change has reduced the groundwater storage which makes groundwater more vulnerable to geogenic contamination. In this study the groundwater quality of Pavagada taluk is assessed using multivariate statistical techniques to understand the influence of various factors on the characteristics of groundwater. To spatially explore the control of each factor on the various region of the study area spatial distribution maps of principal component scores are prepared to identify the probable source of contamination. To ascertain the status of groundwater quality 102 samples were collected and 15 parameters of each sample were analyzed to evaluate its cationic and anionic concentration. The major rocks in the study area are Closepet Granite and Peninsular Gneisses and the intrusion of Dolerite dykes can be seen at various locations in both of the rocks. Hierarchical cluster analysis classifies water samples in to two groups which are distinguished by electrical conductivity and variation of major ion constituents. Principal component analysis revels that geogenic contamination significantly affected the quality of groundwater compared to anthropogenic sources. PC1, PC2, PC3 and PC4 explain geogenic contamination of groundwater whereas PC5 explains anthropogenic contamination by leaching of agrochemicals.