Oxygen-less Madipakkam lake gasps for survival, kills fishes

CHENNAI: The Madipakkam lake, one of the few remaining large water bodies in the city, appears to be fast turning into   a graveyard for the fish it breeds.
For the past three days, hundreds of dead fish are being found on the shores of the lake due to depleting oxygen levels.

Krishna Kumar, a local resident, said he had seen the lake shrink over the years. The water body could well be Chennai’s ‘Vedanthangal’- a delight for bird watchers.
The tag which he gives to the lake, spread over 20 acres, is appropriate as numerous water birds, including spot-billed pelicans, can be seen throughout the day. “Besides birds, there were countless fish, but not anymore. The fish are dying thereby threatening the ecosystem. This shows the lake is in urgent need of rejuvenation,” he said.

It all began when residents of Ayyapa Nagar bordering the lake complained to the local civic authorities on Wednesday about fish dying in the lake. Corporation officials cleared the dead fish the next day. Five teams, each comprising two persons, were deputed for the task. Furthermore, acting in tandem with the fisheries department, health and sanitary officials of the corporation (ward 187) found that oxygen in the lake was well below the required level.  
Using the dissolved oxygen meter, they found that the oxygen level in the lake had dropped to three mg/L, when it should have been at least seven mg/L.
In certain areas of the lake, the oxygen level decreased to as low as one mg/L, which officials say explains the death of fish.

Another resident, T V Ramakrishnan, who had been living nearby for the past 28 years, said he had not seen any periodic maintenance work at the lake. “The smell of dead fish has permeated the locality. I have never seen this (dead fish) on such a large-scale in the past,” he said.
As an immediate measure, dissolvable oxygen granules were procured. “A boat was hired, using which the granules, weighing 10 kg, were sprinkled on the lake’s surface. This has helped partially improve the oxygen level so that the situation doesn’t turn worse,” S Ramaiah, health and sanitary inspector told Express.

He explained that the present situation was due to decreasing water quantity, diminishing oxygen levels and breeding of fish uncontrollably.
There as six inlet pipelines to the lake, which convey  domestic untreated waste water to the lake - no longer a drinking water source that it used
to be.
 “There is a proposal on our side to construct a tank which would treat this inflow of waste water. However, it is the Public Works Department, that is responsible for maintaining the lake,” the official said.