Seasonal groundwater quality assessment and irrigation suitability in coastal aquifers of Puri District, Odisha, India

Assessing seasonal groundwater quality in coastal aquifers is critical for ensuring sustainable drinking water supply and irrigation management under increasing anthropogenic and climate-induced pressures. This study evaluates the spatio-temporal variation of groundwater quality across four hydrological seasons winter (December-February), pre-monsoon (March-May), monsoon (June–September), and post-monsoon (October-November) in the coastal aquifers of Puri district, Odisha, India, during 2021–2022. Groundwater samples collected from twelve representative monitoring locations were analyzed for major physicochemical parameters, including pH, EC, TDS, total hardness, major cations (Ca²⁺, Mg²⁺, Na⁺, K⁺), and major anions (Cl⁻, SO₄²⁻, HCO₃⁻, NO₃⁻, and F⁻). Drinking water suitability was assessed using BIS (2012) and updated WHO (2022) guidelines, while irrigation suitability was evaluated using Sodium Adsorption Ratio (SAR), Kelly’s Ratio, EC, TDS, and USSL classification. The Water Quality Index (WQI) was employed to integrate multiple parameters into a single indicator of potability. Results reveal that groundwater quality ranges from good to excellent across most seasons, with localized deterioration during pre-monsoon and monsoon periods due to salinity enrichment and anthropogenic inputs. Irrigation indices indicate predominantly low to moderate sodium and salinity hazards, confirming suitability for agricultural use. The study provides a comprehensive seasonal and multi-index assessment of groundwater quality in a sensitive coastal aquifer system and contributes to SDG-6 (Clean Water and Sanitation) and SDG-13 (Climate Action) by supporting evidence-based groundwater management and climate-resilient water planning.