The decks have been cleared for the long-pending proposal to construct a training wall at the mouth of the Cooum river to minimise sand bar formation.
The Water Resources Department will call for tenders for the work in a few days as coastal regulation zone clearance has been obtained.
The Cooum had carried nearly 13,000 cusecs during heavy rain last year.
The officials said nearly 24,000 cusecs of water drained into the sea from the Cooum during the 2015 floods. However, the flow was inadequate to reduce the development of sand bars at the mouth. Moreover, the presence of Chennai harbour accelerated the sedimentation.
The department has planned to build a training wall on either side of the mouth perpendicular to the sea to ensure permanent opening of the river mouth and direct the river flow into the sea.
The training wall has been planned to be built for a length of 265 metres on the northern side and 310 metres on the southern side at an estimated cost of ₹70 crore.
It would be built as a combination of boulders and concrete tetrapods and based on the design and suggestions provided by the National Institute of Ocean Technology. The structure would allow smooth tidal exchange, easy draining of flood water and help in coastal protection, the officials said.
At present, only five metres of the mouth remains open. Steps would be taken to clear the sand bars to keep the river mouth open temporarily during the rainy season until the project was started.
Once the project is completed in 18 months, the impact of tidal exchange would be felt till Chetpet bridge. It now reached only up to Chintadripet. Sewage outfalls in the river must be plugged for sustainable eco-restoration of the river, the sources said.
A similar project to build straight training walls at the mouth of Ennore creek to minimise floods in the upstream areas is yet to kick off due to paucity of funds. The proposal is awaiting tie-up with Kamarajar Port Ltd.
Published - September 19, 2022 09:19 pm IST
