Chennai flooding exposes drainage gaps as heavy rain disrupts city

Heavy rainfall has caused waterlogging in parts of Chennai, exposing gaps in stormwater drainage infrastructure in north Chennai and Velachery despite overnight clearance operations by the Greater Chennai Corporation.

The flooding has affected residential streets and transport routes, with residents raising concerns about clogged canals, incomplete drainage connections and infrastructure works that remain unfinished as the northeast monsoon progresses.

Chennai recorded 10.5 cm of rainfall in the 24 hours ending at 6 am on Sunday, October 18, according to the rainfall figures reported by The Economic Times on Monday. The report also listed 36.3 cm at Parry’s and 34 cm at Ennore Kathivakkam during the reported rain episode.

More than 15,000 Greater Chennai Corporation workers worked overnight to clear waterlogging from 35 roads and 16 subways. However, some residential streets remained flooded.

In Velachery, knee-deep water was reported in parts of Bhuvaneswari Nagar, Ram Nagar, AGS Colony and Tansi Nagar. Residents attributed the problems to drainage blockages and incomplete links in the stormwater network.

North Chennai also reported flooding concerns. In Vyasarpadi, residents highlighted delays affecting a flyover project and drainage work associated with Otteri Nullah.

The problems have renewed questions about the coordination of stormwater drainage projects, particularly where newly constructed drains have not been fully connected to existing canals and outlets.

The India Meteorological Department’s bulletin issued on October 18 forecast heavy to very heavy rainfall at isolated places across Tamil Nadu, Puducherry and Karaikal from October 18 to 21. Isolated heavy rainfall was also forecast from October 22 to 24.

The continuing rain increases the pressure on drainage systems that are incomplete, obstructed or unable to discharge water quickly enough.

While the corporation’s overnight operations cleared several roads and subways, the continued flooding in residential areas indicates that water removal alone may not address the underlying infrastructure problems.

The immediate priorities include maintaining drainage channels, clearing obstructions and completing pending links so that stormwater can flow into designated outlets.

The episode highlights the need to assess the performance of the drainage network during sustained rainfall and establish which incomplete or obstructed works require urgent intervention.