The Water Resources Department will start dredging the Adyar river mouth to prevent sedimentation as the Union Ministry of Environment, Forest and Climate Change had recently provided coastal regulation zone clearance for the project.
Following the Expert Appraisal Committee’s recommendations, the department had roped in National Institute of Ocean Technology to conduct a study on sustainable opening of the Adyar river mouth and its impact on riverine ecology, biodiversity and Besant Nagar turtle nesting site.
The Union Ministry has sanctioned the project proposed by the Chennai Rivers Restoration Trust and has laid conditions to execute the work based on the recommendations of the NIOT study.
Officials of WRD said river water quality should also be monitored through the National Centre for Coastal Research, which is monitoring seawater quality along coastal areas. The study has recommended that the desilted sand from river mouth be deposited on the northern side till Marina and prevent erosion. It had also recommended that dredging exercise of the estuary must be carried out in summer to avoid disturbing the turtle nesting season.
Dredging would be done during May and June every year to keep the river mouth open and help beach nourishment on the northern side. Nearly 2 lakh cubic metre of sediment has to be removed and dumped in the north of the waterway, officials said.
Meanwhile, about 50% of the work to desilt and widen the 2 km stretch between the mouth and Thiru.Vi.Ka. bridge has been completed so far. Officials noted that nearly two lakh cubic metre of silt has so far been cleared from the riverbed out of the 4.86 lakh cubic metre of silt estimated to be removed.
While a portion of it would be used to strengthen the river bund, dredged silt would also be transported to Greater Chennai Corporation’s dumpsites, officials added.