Hydro-geochemical studies of groundwater in Sathankulam region, Southern Tamil Nadu, India

Groundwater hydro-geochemical studies were evaluated using a Geographic Information System (GIS) in the Sathankulam area of Tamil Nadu, Tuticorin district, India. The average hydro-geochemical analytical data, including pH, EC, TDS, Cations, Na, K, Ca and Mg, Anions, HCO3, SO4, Cl, and NO3 of groundwater samples collected from open and bore well for this period of two seasons, such as the average pre-monsoon and post-monsoons. By utilising the ArcGIS-10.8 programme, different thematic water quality maps based on hydro-geochemical parameters were observed. The spatial distribution of integrated parameters for the groundwater quality maps of Ca, Mg, Na, K, HCO3-SO4-Cl, and TDS was obtained using interpretation techniques, such as the Inverse Distance Weighting (IDW) method. The combined hydrochemistry software (HYCH) programme, developed by Balasubramanian et al. (Hych-basic computer program for hydrogeochemical studies. In: Proceedings of Vol. Nat. Sem. On Water, Govt. of Kerala, Trivandrum, 1991) was used to process and evaluate all groundwater environmental data. The HYCH software programme includes the water quality environmental parameters output, including Handas classification of hardness, Corrosivity ratio, Scholler classification of compositional variation, Stuyfzand classification of salinity, United States Salinity Laboratory (USSL) classification, Gibbs mechanism, Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC), Permeability Index (PI), and Piper environmental classification of groundwater. Arc GIS software also generated a number of thematic environmental spatial maps for the HYCH output. Results from HYCH output help to categorize the water quality as good, bad, and satisfactory for domestic and irrigation use.