The sharp rise in water contamination in reservoirs, from 10 per cent last year to 22 per cent this year, has set alarm bells ringing in the civic body. Two years ago, there was no contamination at all at the city's reservoirs.
Civic officials said the reservoirs were very old and cracked in some places, which leads to seepage. "There is also a lot of silt accumulated in the reservoirs. Desilting has been carried out at some reservoirs," said an official of the Hydraulic Department.
Since the reservoirs are being desilted and repaired, officials expect that next year contamination levels will fall. Desilting work is complete at reservoirs at Malabar Hill, Golanji Hill, Worli and Azad Maidan.
Additional Municipal Commissioner Anil Diggikar said the findings of the Environmental Status Report, which recorded the rise in contamination levels, were alarming and that he would call a meeting to discuss how to deal with the problem.
The civic body is considering installing toxicity analysers at the reservoirs to get early information about contamination. "The analysers could raise an alarm and the water supply could be stopped automatically," an officer said.
These analysers would be initially fixed at three reservoirs — at Malabar Hill in the island city, at Veravli in the western zone and at Trombay in the east. Depending on the results, the analysers would then be installed at all 26 reservoirs.
"Countries like Germany and Sweden are using this system to protect reservoirs from contamination," said the officer.