Assessment of environmental variables in Cauvery River and its tributaries

This research paper pertains to the variation in water quality with special reference to physicochemical and biological parameters in Cauvery River and its tributaries in India over a period of 1 year. The quality of water in four streams of Cauvery River in Mysore, Mandya and Chamaraja Nagar districts, where many small scale sugar, paper industries and agricultural lands are located were analyzed. Sampling was carried out from Cauvery and its tributaries which were designated as stations 1, 2, 3 & 4 (all towards down streams of Cauvery River). The river water composition is increasingly dominated by PO4, NO3 Cl at stations 3 & 4 compared to stations 1 & 2. Significant spatial variations were observed in water level, transparency, turbidity, colour, DO, BOD, NO3, NO2 and total hardness among the physico-chemical parameters at the study locations. The DO level at stations 3 & 4 was lower than 5.0 mg/L, which is the recommended minimum allowable limit for aquatic life. 30 species of phytoplanktons were identified under five classes: viz, Chlorophyceae, Bacillariophyceae, Cyanophyceae, Euglenophyceae and Desmidaceae. About 20 algal species were recorded at station 1, 16 at station 2,13 species at station 3 and 14 species at station 4. The overall diversity and density of algae at four stations was significantly different. A posterior comparison revealed that stations 3 and 4 are the cause of significant difference. The chlorophyceae members, which dominated the algal community, were found to tolerate the effluent effect at stations land 2. Low algal diversity and negative impact on the biotic and abiotic environment were experienced at stations 3 and 4 throughout the duration of sampling, because of man made activities.