How does physicochemical variability characterize surface water quality in a subtropical tributary?

Rivers and their tributaries in the northeastern Bay of Bengal play essential roles in supporting local livelihoods and ecosystem services, yet comprehensive water quality assessments remain limited. This study investigates spatiotemporal variations in physicochemical parameters within the Chowfaldandi tributary of the Matamuhuri River over the 2022-2023 hydrological year. Standard analytical methods were employed to analyze water and air temperature, water salinity (WS), total dissolved solids (TDS), total suspended solids (TSS), transparency (TR), water pH, and dissolved oxygen (DO). Seasonal variation was statistically significant for all parameters except transparency and pH, while spatial differences were minimal. Principal component analysis revealed two dominant components: PC1 (positive loadings for pH, TSS, TDS, DO, and WS) and PC2 (positive loadings for TDS, DO, pH,…