A proposal to keep the Ennore estuary free of sand bar formation is awaiting funds. The Water Resources Department recently submitted estimates for the project, significant for smooth freshwater exchange with the sea and mitigation of floods.
The estuary — at the confluence of the Kosasthalaiyar river, the North Buckingham Canal and the sea — often gets clogged with sand deposits. At present, its mouth is only 50-75 m wide, and this often hinders tidal wave action and the free flow of water.
The ₹140-crore project was designed based on a study by the National Institute of Ocean Technology (NIOT) on ways to reduce siltation in the estuary. WRD officials said the proposal had been sent to Kamarajar Port Limited for approval, and they were expecting funds this month.
“We completed the project to build nine more groynes between Ennore and Ernavoorkuppam in July to arrest shoreline erosion. The project will help resolve issues affecting the fragile ecosystem in the estuary,” said an official.
The project proposes to construct groynes measuring 650 m and 300 m on either side of the estuary. A gap of nearly 500 m length and 200 m width will be maintained by dredging operations. This will allow free flow of freshwater into the sea for a longer period and protect the livelihood of fishermen in neighbouring areas.
Recalling that sedimentation in the estuary led to flooding in areas abutting the Buckingham Canal and the Kosasthalaiyar river, R. Venkatesh, a resident of Periakuppam, said it was important to deepen the estuary to reduce waterlogging in areas like Manali and Ennore. The estuary was also heavily polluted with fly ash and sewage.
Efforts to keep the estuary mouth open would help address the issue, he said. Fish catch would also increase as water would be cleaner for marine life to feed and reproduce, he added.
The new groynes will differ from the straight groynes built in other places such as the Cooum river mouth. Scientists at NIOT said curved groynes will be built in the Ennore estuary to deflect sand into deeper waters and slow down siltation in the estuary. They will also function as a breakwater structure for the safekeeping of fishing boats. The depth at the mouth will also be increased by 1 m to enable smaller boats to move into the sea.
Last year, a portion of the estuary mouth was cleared of sand bars by the WRD as part of monsoon preparedness work.