Water Resources Department completes 40% of work to construct training wall at Cooum river mouth

Water Resources Department completes 40% of work to construct training wall at Cooum river mouth

The persistent issue of sand bar formation at the mouth of the Cooum may have a permanent solution in about six months as work to build a training wall near the mouth and also dredge the waterway to minimise sedimentation is progressing at a good pace.

The Water Resources Department (WRD) has completed nearly 40% of the work on the training wall on either side of the mouth, perpendicular to the sea. The groynes already laid at the mouth were removed to ensure permanent opening of the river mouth and direct water flow into the sea.

WRD officials noted that a combination of boulders and concrete tetrapods are being laid as part of the ₹70-crore project. “We did not go for boulders for the entire height as quarrying and transporting boulders of such massive weight was not possible. Instead, we are laying a mix of concrete tetrapods, weighing 4-8 tonnes, over a layer of boulders. This will prevent the boulders from dislocating during the monsoon,” an official said.

The structure, which would be nearly 8 m high at its deepest portion, would facilitate easy draining of floodwater, smooth tidal action and prevent coastal erosion, officials said.

The river has a carrying capacity of 25,000-30,000 cubic feet per second (cusecs). Every year, heavy machinery would be deployed to remove the sand bars ahead of the monsoon to prevent floodwater from inundating localities along the upstream portions of the river.

While the training wall on the southern side has been laid for a length of 260 m of the total distance of 310 m, about 210 m of the proposed 265 m has been covered on the other side. About 4,500 tetrapods will be placed in total, officials said.

The work is being carried out based on the design provided by the National Institute of Ocean Technology (NIOT). Moreover, the WRD is dredging the riverbed to remove silt deposits. Nearly 1 lakh cubic metre of sand deposits have been removed so far. The remaining 75,000 cubic metre of deposits will be removed in a few months.