Training wall planned on mouth of Cooum to check deposits of silt

On average, nearly ₹1.5 crore is spent every year to remove sand bars from the river’s mouth using heavy machinery.

On average, nearly ₹1.5 crore is spent every year to remove sand bars from the river’s mouth using heavy machinery.  


River’s minimal flow not enough to prevent blockage by formation of sand bars

In a bid to minimise sand bar formation on the Cooum river mouth and ensure smooth tidal action, the Water Resources Department has proposed to construct a training wall, a structure to direct the river flow, at the mouth.

The river only has minimal flow for the most part in a year and that is insufficient to reduce blockage by sand bars. Moreover, the presence of the Chennai Harbour also leads to rapid sedimentation at the river’s mouth, according to officials of the WRD.

The Department has submitted a ₹70-crore proposal to the State to build a training wall perpendicular to the sea for sustainable opening of the river mouth. On an average, nearly ₹1.5 crore is being spent to remove the sand bars every year.

Avoiding inundation

It is essential for at least two-third of the river mouth, which is nearly 150 m wide, to remain open for free flow of water and reduce inundation in the areas along the river. Though machinery is involved in dredging the mouth to clear sedimentation, it often gets clogged with sand deposits. The project will help decrease maintenance cost and also drain floodwater without any hindrance during monsoons, said officials.

Recalling that several measures were taken in the past to keep the river mouth open, WRD officials said this included construction of a regulator during the 1970s. However, it stopped functioning after some years. Groynes were constructed on the southern and northern sides of the mouth about two decades ago as one of the solutions.

The coastline also faces sea erosion during a minimum of three months in a year due to the littoral drift. However, the stretch near Marina beach is slowly expanding due to the groynes provided near the river mouth. The new structure will be built without disturbing the groynes already laid and will also help coastal protection, officials added.

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Printable version | Jan 20, 2020 12:01:47 PM | https://www.thehindu.com/news/cities/puducherry/training-wall-planned-on-mouth-of-cooum-to-check-deposits-of-silt/article30507368.ece

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