CHENNAI: The Muttukadu Lake, which turned toxic due to untreated sewage being let out by residential buildings, is likely get a fresh lease of life. It is learnt that Chennai Metropolitan Development Authority is planning to make it mandatory for apartment buildings that have more than 25 dwelling units to set up a sewage treatment plant (STP) in the water-shed catchment area of Kovalam Basin.
The Second Master Plan Land Use and Environment Monitoring and Review Committee have insisted on the provision of STP for smaller developments for the catchment for Buckingham Canal. It has recommended amending the development regulation not just for apartment buildings but also for commercial/institutional/industrial developments exceeding floor area of 1,500 square metres in the area. The same recommendation applies to developments exceeding 500 square metres in the villages falling under the aquifer recharge area.
This comes after Chennai Corporation commissioned German Development Bank KFW study on “Integrated Storm Water Drain projects for extended area of Chennai City.” It is learnt that government is considering a proposal to construct drains in the South coast watershed of Kovalam basin which has three watersheds – South coast, Pallikaranai and South Buckingham canal.
It was The New Indian Express in July 2014 that brought to light the toxicity of Muttukadu Lake, which got a greenish tinge due to harmful algal bloom of the colonial form of microcystis aeruginosa. A study has found that algae bloom is due to dumping of untreated sewage which had resulted in a spike in inorganic nutrients nitrate and phosphate that in turn made the warm tropical water the perfect cocktail for the algae to bloom.
A study published in Indian Journal of Geo-Marine Sciences on February 2014 documents the first occurrence of a harmful algal bloom of colonial form of microcystis aeruginosa in the backwater on June 2012
Muttukadu water is highly polluted as it has high level of nitrates. A minimum level should be less than 0.5 mg/l
Muttukadu has nitrate value of 8.07 mg/l
High values of water hardness is due to large regular flow of sewage and detergents