Impact of water quality on production and productivity in Bellandur lake, Karnataka

Bellandur lake is considered to be the largest water body in Bengaluru city with catchment area of 287sqm and water storing capacity of 17.66 million cubic feet. Water quality of this lake has been a major issue for a long time with foam appearance and accidental burning of the same has become national news in recent times. Eleven parameters from three different location of the lake were monitored from March, 2014 to December, 2017. Majority of the physico- chemical parameters were beyond the optimal range for surface waters and biological parameters also above the desirable limits. Heavy metals concentrations were also high with major source from untreated sewage, industrial effluents, solid waste etc. Dissolved oxygen was nil in many seasons at various location with high BOD concentrations indicated that this lake was containing copious amount of organic load which was utilizing dissolved oxygen for decomposition by microbes and making the water body anaerobic at times. There is a need for proper management measure to rejuvenate this water body by stopping all the illegal entry of pollutants.