Bidyadhari—A Sewage-Fed Tidal River

Small streamlets like Nona Gung, Noai, Sunti and Yamuna rivers form the river systems of Bidyadhari. Originating from the district of Nadia and outfalls in the Jhilla River of the Sunderbans, Bidyadhari has been carrying wastewater effluent of the megacity Kolkata since the British period by which the river got polluted all along its tidal stretch from Haroa upstream to Malancha Downstream. The point sources of mixing of domestic wastewater and industrial effluent from Kolkata metropolis are the places of union of canals. The concentrations of determinants of declined water quality like dissolved oxygen of the river water are very low and even sometimes are below detectable limit. The water quality rating in the context of the values of computed water quality indices is extremely low in conditions that indicate its extremely poor usability in all aspects for agriculture, aquaculture and domestic uses.