Investigation of Seasonal Variation in Groundwater Quality Using Water Quality Index (WQI)

Abstract

Groundwater is an important source of domestic and drinking water in Shrigonda Town, Maharashtra, where seasonal recharge and local land-use conditions may influence water quality. This study investigated seasonal variation in groundwater quality using the weighted arithmetic Water Quality Index (WQI) and spatial analysis. A total of 95 groundwater samples were collected from borewells during the pre-monsoon season in May 2024 and the post-monsoon season in February 2025. The sampled borewells ranged from 150 to 500 feet in depth and supplied water for domestic and drinking purposes. Physicochemical parameters were analysed in the laboratory, and WQI values were used to classify groundwater suitability. Groundwater quality was generally poorer during the pre-monsoon season. In Wards 3, 4, 6, 7, 8, and 9, all sampled locations were classified from poor to non-drinkable during the pre-monsoon period. Following the monsoon, 55.79% of the samples improved to the good-quality category, with good or excellent groundwater occurring in parts of Wards 1 and 5 and improvement also observed in Ward 2. Nevertheless, 42.11% of sampling points remained water-quality hotspots in both seasons. The findings demonstrate a clear seasonal pattern, with post-monsoon improvement consistent with recharge and dilution effects, while persistent hotspots indicate the need for continued monitoring, source-level investigation, recharge enhancement, and local pollution-control measures.