GCC failed to fix gradients, reverse flows

As per the storm water drain maps released by the Chennai Corporation, inlets of GKM Colony 24A Street Pond and 9th Street Pond have been marked as reverse gradient drains. This suggests the accumulation of silt during the period when the survey for mapping was conducted.

Despite being a comparatively posh locality in Kolathur, Poompuhar Nagar was completely flooded with knee-deep water. The irony is that Poompuhar Nagar has its own pond named Thiruveedhi Amman Pond on 28th Street. Residents said that the civic body had desilted the pond and built walkways and compound walls around it a few years ago. However, when DT Next visited the site, the walkway was in poor condition. There is a sluice gate at the pond to control inflow. “But the gate remains closed for several months. Despite the heavy waterlogging in Poompuhar Nagar, the officials refused to open the gate and let the water into the pond,” Arun added.

Angusamy, a shop owner on 28th Street said the rainwater would not enter the pond from the storm water drain. “To let the flow of rainwater into the storm water drain on the road, the Corporation officials opened the manholes. But the rainwater reverse flowed from the manholes. The entire Poompuhar Nagar got flooded and senior citizens got sick as the sewage got mixed with rainwater,” he said.

Apart from the poor management of ponds, similarly to the other affected areas, the storm water drain network in Kolathur has been poorly linked. For instance, Siva Ilango Road (70-Feet Road) is a major road in Kolathur where the civic body dug out the storm water drain to reconstruct after the rains.

During the floods, rainwater from the Siva Ilango Road storm water drain was pumped out to a nearby street, from where water flowed due to the natural gradient. The faulty storm water drain on the road caused heavy flooding in Jawahar Nagar and other surrounding areas.

Arun explained that Baba Nagar, which is an elevated area than other areas in Kolathur, witnessed waterlogging. “A culvert at the junction of 4th Main Road and Baba Nagar 3rd Main Road was blocked, which caused waterlogging in Jagannathan Nagar and Baba Nagar. Chief Minister Stalin inspected the area after which the block was cleared. Now water is flowing freely,” Rajesh, a resident, said.

Arun suggested that the civic body should conduct a trial run of storm water drains by pumping water soon after the construction of drains to find out reverse flows and blocks.

Meanwhile, Radhakrishnan of Arappor Iyakkam pinned the blame on the Chennai Corporation for the recent floods and said the city-wide survey was conducted on storm water drain networks to prepare storm water drain maps between December 2020 and February 2021. “As per the maps, the Corporation could have details of gradients and reverse flows. They had eight months to rectify the issues. If they had addressed the issues based on the maps, people would not have suffered during the rains,” Radhakrishnan added.