Posted on January 8, 2024
Work to desilt a two-km stretch of Adyar river, close to its mouth, is expected to be completed by February.
Instead of building a training wall, silt would be cleared during peak summer from the river mouth to enhance beach nourishment in the area.
The Water Resources Department has completed nearly 90% of the desilting work in the two-km portion between Thiru.Vi.Ka. Bridge and the mouth. Of the 4.86 lakh cubic metres of silt estimated to be cleared from the stretch, nearly four lakh cubic metres of silt has been removed so far. About three lakh cubic metres of silt has also been conveyed to Greater Chennai Corporation’s dump yards, and also to be used in facilities like parks, said officials.
The exercise would help smoothen tidal exchange closer to the estuary and also ensure free flow of water. The Adyar river had carried a flow of a minimum of 30,000 cubic feet of water per second during heavy rain in December last year.
The operation would not be complete without dredging the Adyar river mouth to prevent sedimentation. However, instead of building a training wall for sustainable opening of river mouth like in other estuaries, the WRD has planned to dredge the river mouth every year.
The Department had earlier obtained the Union Ministry of Environment, Forest and Climate Change’s coastal regulation zone clearance for the project to dredge the river mouth. Officials said the ₹11-crore work would be carried out during May without disturbing the turtle nesting season. The estuary would be dredged for a length of 400 metres and a width of 400 metres, covering both the river and sea sides.
About two lakh cubic metre of sand estimated to be removed would be used to enhance beach nourishment on the northern side, in places like Srinivasapuram. The sediment would be examined by the Zoological Survey of India. Equipment like slurry pumps would dredge the mouth and increase the sand volume in the beach for two km, officials said.
In its study, the National Institute of Ocean Technology had recommended dredging the Adyar river mouth every year as an alternative to a training wall, which may lead to sand erosion in other stretches.
The upstream portions of the river, including those near Kotturpuram, have gained more silt after the recent heavy discharge into the river. However, sources said the stretch would need a desilting exercise after five years as silt was removed recently. Dismantling the old bridge near Thiru.vi.ka. bridge also needs to be considered as it often obstructs the river flow.
