Interpretation of Water Quality Data by Multivariate Statistical Tools:A Study in Mysore District, Karnataka, India

In the management of water resources, variables which control the quality of water, are just as important as its quantity. Hydrochemical assessment of water quality of surface and groundwater for 58 samples was made during postmonsoon of 2007 from strategic locations in Husnur Taluk. Water quality data collected from different localities are used in conjunction with multivariate statistical technique to identify key variables. In surface, four components were extracted which account for 84.46% of the total variance. The first component shows that the EC and TDS play an important role in the hydrochemical constituents of the surface water. In groundwater samples, 5 components were extracted, which account for 95 % of the total variance. The maximum number of variables, i.e., Na, Cl, SO₄, TDS and EC were characterized by the first component and show that the hydrochemical constituents of groundwater are mainly controlled by the first component. The 'single dominance' nature fourth and fifth components in PCA indicate non-mixing or partial mixing of different types of groundwaters. The findings of the cluster analysis are presented in the form of dendogram of the sampling stations (cases) which produced three major groups.