Water Quality Index-based Groundwater Assessment for Irrigation and Drinking Purposes in Erode District, Tamil Nadu, India

Groundwater is an essential water resource for drinking and irrigation, especially in semi-arid areas such as Erode District, Tamil Nadu, India. This research assesses groundwater quality both for drinking and agriculture using standard water quality indices. 48 groundwater samples were gathered from 44 villages in the premonsoon season of 2021 and analysed for physicochemical parameters such as pH, electrical conductivity (EC), total dissolved solids (TDS), major cations (Ca²⁺, Mg²⁺, Na⁺, K⁺), and major anions (Cl⁻, SO₄²⁻, CO₃²⁻, HCO₃⁻, NO₂⁻+NO₃⁻) as well as fluoride. Drinking water quality was determined via Water Quality Index (WQI), while irrigation suitability was determined via Sodium Adsorption Ratio (SAR), Residual Sodium Carbonate (RSC), and Sodium Percentage (Na%). Results indicated that 23% of the samples were excellent, 43% good, 25% poor, and 9% unsuitable for consumption. 82% of the samples had low sodium hazard as per SAR, 77% were good as per RSC, and 37% doubtful as per Na%. Spatial analysis showed that the deterioration in groundwater quality was stronger in the east and center of the district, which pointed out the area of concern. The research presents new, location-specific information that can be used to develop sustainable groundwater management measures such as monitoring, remediation, and policy planning. These results emphasize the necessity of continuous monitoring of groundwater quality for guaranteeing safe drinking water supply and sustainable agricultural production in areas with intense farming and industrial pursuits.