Assessment of Spatiotemporal Variations in Water Quality of the Urban River Reach, Yamuna, Delhi

Yamuna River Delhi stretch is a leading source of water supply to Delhi. The river stretch is a receptacle of urban liquid waste of human interference from domestic and industrial fields and conduces to the most contaminant reach of the country. The present study used multivariate techniques to represent the spatiotemporal water quality variations and interpreted a large hourly complex dataset (March 2021–February 2022) obtained from two real-time monitoring stations situated upstream and downstream of this reach. Eleven water quality parameters were assessed, and Box Whisker plots were drawn monthly basis. The increased concentrations of conductivity, BOD, COD, TOC, NH4, and low DO downstream indicated the influence of outfalling drains and diffused sources contributing pollutants into the river stretch. A higher BOD, COD, and TOC concentration was observed downstream in monsoon attributed to the organic substance in surface runoff. FA and PCA were implemented in the standardized data set to reveal the correlation between the water parameter. For upstream, turbidity, TOC, COD, and TSS have strongly positively loaded for factor 1 for all the seasons except monsoon. For downstream. TOC and COD contributed strongly positive load except in winter. The study reveals that the urban river flows with agricultural and surface runoff: industrial and domestic wastewater with organic and inorganic substances. This present study is a novel approach to assessing spatial and temporal variation of an urban reach for the current geomorphological conditions with real-time data.