CHENNAI: The original storage capacity of four major reservoirs, which are the city’s primary source of drinking water, has been reduced considerably due to silt accumulation in the bed over the years. To improve the existing condition of the reservoirs and to restore their built-in capacity, the State government has passed an order to first begin desilting of Cholavaram tank and has allocated Rs 5.25 crores for maintenance works. Since the reservoirs were built in the 1800s, this is the first time they will be desilted, officials said.
According to data accessed by Express, the total capacity of Cholavaram reservoir has been reduced by 50 per cent. While it was initially built to hold 1081 mcft, due to silt accumulation its capacity has shrunk and it can store only 544 mcft now.
The project which was supposed to commence by May 2018 has been delayed due to tender processing and will begin once the Northeast monsoon ends by January, said officials from Water Resource Department, which is spearheading the project. “The tender has been floated and once the price order for the tender is finalised and other pre-qualifications are met, Chovalaram tank will be desilted in the next three months,” the official added.
The detailed project report was submitted to government six months ago and will be carried out in a phased manner, officials said. “It will take close to three to five years to completely desilt all four reservoirs because in a year we can carry out the work only during five months. Only when the water levels are relatively lower, we can remove silt from its bed.
Our target is to remove silt for 20 days in a month when the bed is partially dry,” said an official. “Based on the extent of repair in each tank, funds for civil work will be sanctioned which might vary from Rs 3-8 crore. We were informed that in two weeks, a GO sanctioning funds for other three reservoirs will be passed.” The project will bring around Rs 640 crores to the State as builders can purchase desilted sand from the government.