Gurgaon: The sewer repair work near IFFCO Chowk will take at least five days.The repair work on the 1,000mm-diameter master sewer line beneath the service road has started after sewage flow was diverted to an alternate manhole and the affected area was dewatered, paving the way for rehabilitation of the underground pipeline without major excavation of the busy road.GMDA officials said that the repair work would take around five days, although the timeline could depend on the extent of damage identified as rehabilitation progresses.The cave-in occurred on Tuesday when a portion of the service road gave way, initially creating a sinkhole of around 10 feet. The opening widened to more than 30 feet within hours. Police and NHAI immediately barricaded the affected stretch, while GMDA began arrangements to divert sewage and dewater the site.National Highways Authority of India (NHAI) said it will start the restoration of service once the sewer pipeline is rectified.“We are continuously coordinating with GMDA and once the sewer pipeline is rectified, we will start with the service road restoration,” an NHAI official said.The metropolitan authority is currently taking up machine-wound spiral lining (MWSL) on the stretch of around 100 metres of the sewer line. The total length requiring rehabilitation will be assessed as the work progresses, officials said.MWSL is a trenchless rehabilitation technique, similar in purpose to CIPP (cured-in-place pipe) lining, in which a new structural PVC pipe is built inside the existing damaged sewer line. The method allows an ageing or damaged pipeline to be strengthened from within without having to excavate the entire stretch of road.A GMDA official said the sewage flow was first diverted to an alternate nearby manhole and the affected area was completely dewatered. Once the water was removed, the engineering team was able to inspect the sewer line and begin rehabilitation.“MWSL is a trenchless technology similar to CIPP. The two technologies are almost similar in terms of their purpose and both can extend the life of an old sewer pipeline by around 50 years. We have already used CIPP technology at several locations in the city, but in this case we are opting for MWSL because it is more suitable for the site conditions and the repair requirement,” the GMDA official said.Under the MWSL method, a specialised winding machine works from access points such as manholes and continuously winds a PVC profile strip inside the existing sewer. The interlocking strip forms a new pipe within the old one, effectively creating a renewed internal lining.The process is aimed at restoring the structural integrity of the ageing sewer line while also providing a renewed internal surface that can help prevent leakage and further deterioration.The rehabilitation of the sewer line is expected to cost around Rs 70 lakh for the initial 100m stretch.“We are initially taking up 100 metres, but if inspection during the repair reveals damage at additional locations, those portions will also be assessed and taken up as required. The objective is not only to address the present problem but also to ensure that similar issues do not arise in the future. The existing sewer line is quite old and wherever technically feasible, we will use such rehabilitation technology to extend the life of ageing pipelines,” the official added.The sewer line carries sewage from areas including DLF-2, MG Road and IFFCO Chowk towards Behrampur sewage treatment plant. It is an old master sewer line and had not undergone CIPP rehabilitation before the cave-in earlier this week.The service road continues to remain barricaded around the cave-in site, affecting traffic movement towards the U-turn flyover. Commuters coming from MG Road and IFFCO Chowk and heading towards Delhi or Sukhrali are being diverted, with Delhi-bound commuters required to take a U-turn from Sukhrali.IFFCO Chowk is one of the city’s busiest traffic junctions. The flyover at the junction was completed in 2019 as part of a project launched in 2016 to reduce congestion on Delhi-Gurgaon Expressway.The latest cave-in comes weeks after a section of Delhi-Gurgaon Expressway near Narsinghpur caved on July 7, triggering a major traffic jam.On Aug 10, a portion of Sohna Road near Adarsh School caved in after a dumper carrying construction material got stuck.On Aug 7, continuous rain caused a road cave-in near the IFFCO Chowk underpass.
