Evaluating Pre-Monsoon Water Quality through EWQI, Ionic Facies, and Correlation Statistics

Abstract

In monitoring baseline water quality degradation before monsoonal dilution, the pre-monsoon period is especially useful since it is a crucial hydrochemical phase marked by decreased recharge, increased evaporative concentration and extended water–rock interaction. The present article focuses on the hydrochemical assessment of the water samples collected from various location within the study area in order to analyse their physicochemical properties along with the geochemical processes governing them. The Entropy- weighted Water Quality Index (EWQI) was used to assess the water quality after the quantification of main ions and trace constituents using standard analytical techniques. EWQI categorized 15% sample as extremely poor, 17.5% as poor, 40% as average, 25% as good, and only 2.5% as excellent. Gibbs plot was used to determine the mechanism controlling water chemistry, whereas Piper and Durov diagrams were used to compare hydrogeochemical facies and ionic development. The results obtained reveals that the water chemistry is controlled dominantly by the rock-water interaction and is characterised by alkaline nature with moderate to high mineralisation. Pearson correlation was carried out to understand the statistical relationship between the parameters. It clearly indicated that Electrical conductivity has a strong positive relationship with major cations and anions, whereas the trace elements, like arsenic, show weak to moderate correlations with major ions that suggests local and source specific controls on their distribution. A detailed understanding of the state of water quality and the mechanisms affecting solute accumulation before monsoon recharge is provided by the combined hydrogeochemical and statistical method. Moreover, the water quality of the study area needs to be taken into consideration as early as possible since the samples majorly falls in the average category of EWQI.