Dredging of Pallikaranai marshland draws flak

CHENNAI: As the State Water Resource Department is creating a drain inside the Pallikaranai marshland to make the surrounding areas free of water stagnation, environmental activists point out the negative impact of dredging the marsh.

“The marshland was formed due to the flow of rainwater from west to east. The function of the marshland is to receive these runoff water and to discharge into the ocean slowly throughout the year. When the marshland is drained off this critical function, buffering capacity will be lost due to compaction and subsidence,” explains Darwin Annadurai of Eco Society India.

He warned that changing the land use pattern of the marshland will modify its buffering capacity. During extreme weather events, the marshland would fail to absorb excess runoff water resulting in flooding in nearby areas.

“The elevation of the Pallikaranai marshland is lower than the sea level. Even if the drain is created to carry excess water, there would be no flow to the sea. Dredging would bring the level of the marshland further low,” he warns.

G Sundarrajan of Poovulagin Nanbargal concurs and points out: “Dredging of the marshland is against an order of the High Court. We’re going to visit the spot soon and verify whether a drain is formed inside the marshland.”

It may be recalled that the Chennai Corporation in 2020 had proposed to dredge the marsh as a flood mitigation measure but it was stalled after severe censure from environmental activists.

When asked, an engineer with WRD, on condition of anonymity, explains that the drain will prevent flooding in Perumbakkam, Semmenchery and surrounding areas. “The drain will carry excess water to Buckingham Canal and then to Muttukadu. Moreover, we’re not creating any bund or removing earth from the marsh,” he adds.

He opines that the drain already existed in the marsh and the department was only desilting it. “We surveyed the marsh using drones during which we found out the existence of the drain. The work will be completed in a week,” he states.