CHENNAI: Just two weeks after a 21-foot-deep cave-in on Karukku Main Road near Ambattur, a new sinkhole of around five feet depth has emerged close to the previous site. The new sinkhole, which is close to a leaning electric pole, is believed to have been caused by another damage to the same underground sewage pipeline which caused the first sinkhole. It has, once again, disrupted traffic in the area while sparking safety concerns.
Speaking to TNIE, a Chennai Metropolitan Water Supply and Sewerage Board official said the collapse was likely due to damage in the sewage pumping line running beneath the road.
These lines, which are 30-40 years old, carry sewage from Karuppampulam to Karukku and onward to the Korattur and Kodungaiyur treatment plants. Over time, the buildup of gases inside the pipelines creates enough pressure to damage the pipes and this might have allowed surrounding sand to infiltrate the system, weakening the structure. The recent rains would have further loosened the soil, creating a hollow beneath, resulting in the sinkhole, the official said.
On why no permanent options have been looked into despite the same sewage pipeline suffering damage a second time, officials said completely replacing the aging pipelines is not practically feasible immediately. The official said repairs are usually carried out only in the isolated areas of damage, as part of operation and maintenance.
Repair work is set to begin on Tuesday morning. Traffic has currently been diverted to alternative routes including through Chennai-Tiruvallur High Road and East Avenue Road.
In the wake of the cave-in, barricades have been placed around the area, and metro water officials conducted an inspection. A motorcyclist had narrowly escaped injury on August 17 after he, along with his bike, fell into a 21-foot-deep hole at the same location.