Multivariate analysis of inland water quality index in parts of Vapi district, Gujarat, India

ABSTRACT Water resource management substantially depends on water quality (WQ). Anthropogenic and geogenic pollutants in water system are challenging to identify, transport, and properly dispose of, thus demanding frequent monitoring. Study focuses on application of statistical approach to analyse pattern and to monitor WQ parameters of region. Paper presents computation of water quality index (WQI) based on various WQ parameters of the Daman Ganga River situated in Vapi, Gujarat, India. 17 WQ parameters considered were pH, electrical conductivity, temperature (Temp), total dissolved solids, NO2 + NO3, (P-Tot), Ca, Mg, Na, K, Cl, SO4, CO3, HCO3, total hardness, sodium absorption ratio (SAR), and calcium hardness (HAR_Ca). Quartile deviation was carried out as preprocessing technique to identify fair analysis of trend followed by other parameters. Application of PCA followed by varimax rotation factor analysis was attempted to identify contribution of significant parameters. Methods developed by Council of Canadian Ministry of Environment (CCME) and British Columbia (BC) were applied to compute WQI. WQI evaluated were 42.35 and 63.29 for CCME and BC, respectively, based on five significantly influencing parameters, namely, HAR_Ca, SAR, CO3, Temp, and P-Tot. Study signifies the hardness and salinity factors impacting WQ and efficiently reduces subjectivity and bias to determine the WQI model.