The flow of floodwater at the Cooum river mouth may be quicker during the northeast monsoon this year as work on a major portion of the training wall has been completed.
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The Water Resources Department has completed 70% of the training wall, a structure to direct the flow, on either side of the Cooum river mouth.
The ₹70-crore project, when completed, would reduce the formation of sand bars at the confluence point of the river and the sea.
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Sand deposits at the mouth had been a challenge in flood management.
The presence of Chennai harbour nearby had accelerated the formation of sand bars, the officials said.
The department started building the training wall perpendicular to the sea to enable permanent opening of the river mouth. Built using a combination of boulders and concrete tetrapods, work had been finished to build the first layer of boulders on both sides.
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Boulders sourced from Madurantakam have been laid for a length of 310 metres on the southern side and 265 metres on the other side. Concrete tetrapods were being placed as the top layer to prevent the movement of boulders during the rainy season. About 4,500 tetrapods would be placed for the training wall, the officials said. The height of training wall would be nearly 8 metres at its deepest portion and would enhance tidal action and prevent coastal erosion.
The department is continuing the dredging operation in the river to clear the accumulated silt deposits to widen the river mouth to up to 120 metres. Nearly 1.20 lakh cubic metres of sand had been removed so far. The remaining 56,000 cubic metres of sand would soon be cleared.
After the project is completed in December, the portion of the river up to Chetpet may feel the impact of the tidal exchange. Now, the impact had reached only up to Chintadripet. The river has a capacity to carry up to 35,000 cusecs of water.