A comprehensive analysis of groundwater quality: Geospatial and multivariate approaches in Dindigul District, Tamil Nadu, India

This study focuses on a comprehensive analysis of groundwater quality by integrating hydrogeochemical, geospatial, Multivariate Statistical Approaches (MSA), and water quality indices (WQI), along with visualization techniques, in the Dindigul district of Tamil Nadu, India. A total of 69 water samples, collected during pre-monsoon (PRM) and post-monsoon (POM) periods by the Public Works Department, Tharamani, were analyzed for major cations (Na+, Ca+, Mg+, K+), anions (Cl-, SO4-, HCO3-, NO3-), and various physical and chemical parameters such as pH, Total Dissolved Solids (TDS), and Electrical Conductivity (EC). The Water Quality Index (WQI) for Bureau of Indian Standard was calculated to assess water quality for drinking purposes. PRM samples showed poorer water quality due to ion dilution and agricultural influence compared to POM samples. The WQI revealed that 3.4 % of the PRM area had excellent water quality, 40.72 % good, 35.54 % poor, 18.41 % very poor, and 1.91 % unsuitable for drinking. In the POM period, 6.34 % of the area was classified as excellent, 51.03 % good, 40.09 % poor, 2.45 % very poor, and 0.08 % unsuitable. Irrigation water quality indices, including Sodium Percentage (Na%), Sodium Adsorption Ratio (SAR), Kelly's Ratio (KR), Magnesium Hazard (MH), Residual Sodium Carbonate (RSC), and Permeability Index (PI), were also computed to identify suitable zones for sustainable agriculture. Correlation analysis indicated significant positive relationships between TDS and other parameters, like Bicarbonate, Total Hardness, Chloride, and EC during PRM, and Sulphate, Total Hardness, Calcium, Chloride, Sodium, and EC during POM, suggesting that TDS is a key indicator of water quality variations in both periods.