CHENNAI: Three blockages across the Buckingham Canal have disrupted tidal water exchange in the Kovalam-Nemmeli coastal wetland, according to a field observation report by the Wetland Conservation Network. The blockages, allegedly linked to the construction of the Mamallan reservoir, have raised concerns over flooding during the northeast monsoon.
The report is based on field surveys conducted on September 3 and October 16. All three blockages were present on both survey dates and the obstructions were persistent on October 23 as well, the environmental group said.
The first blockage, between Thiruvidanthai and Vada Nemmeli, is said to have been in place since March 2026. Water from the Muttukadu-Kovalam estuary had breached the canal by September 3. By October 16, the mud bund appeared to be strengthened. The second blockage, near the Nemmeli-Thiruporur bridge, cut the canal completely, with mud barriers and other structures across it. At Salavankuppam, a mud barrier blocked the southern stretch of the canal, the report stated.
The network warned that the blockages could stop rainwater from draining into the sea, flooding low-lying areas including the Old Mahabalipuram Road (OMR) corridor. They could also weaken the wetland’s role as a natural buffer against coastal surges. Besides, 16 fishing villages depend on the tidal exchange.
The group said these were its assessments and noted that water levels and flow were not instrumentally measured on either survey date.
Further, on September 3, the group said it documented construction of the Mamallan reservoir continuing near Pattipulam and Salavankuppam, despite reports that the project had been halted pending a high-level committee’s review of its design. Excavators were at work at the site that day, forming embankments and building peripheral drains.
A temporary mud road laid across seasonal marshland has also blocked several natural inlets connecting the wetland with the Manamathy group of lakes, the survey found.
The network has urged the water resources department to remove the canal blockages and restore natural water flow. It asked the department to clarify the basis for the works, which it said were absent from the project’s proposal, design plans or environmental impact assessment, and to release the status of the high-level committee’s review.
