CHENNAI: Even as the Chennai Metropolitan Water Supply and Sewerage Board (Metro Water) is in the process of finalising the contractors to carry out Ring Main System (RMS) to ensure uniform water supply across the city, the water manager has proposed to conduct ground penetrating radar (GPR) surveys to identify underground utilities so as to prevent damages.
According to a report submitted to the Asian Development Bank (ADB), the funding agency for the project, a few weeks ago, the Metro Water proposed GPR surveys as pre-construction planning to identify underground facilities of Metro Rail, Greater Chennai Corporation (GCC), telecom agencies, and Metro Water itself. Based on the survey results, detailed utility relocation plans will be prepared.
“Underground water lines, sewers, storm water drains, gas lines, optical fiber cable networks, and power cables are positioned close to the proposed trench line. Incorrect utility mapping or uncontrolled excavation may rupture or cut these lines, causing water supply interruption, sewage overflow, stormwater blockage, gas leak hazards, communication outage, or electrical faults,” the report said.
Since several stretches of the alignment fall within chronically waterlogged or historically flood-prone areas such as Velachery, Madipakkam, Sholinganallur, and Saidapet, where shallow groundwater, reduced surface gradients, and dependence on storm-drain networks would increase construction sensitivity, the Metro Water proposes localised hydrology and drainage assessment.
The RMS project will be implemented in three packages based on geographical, operational and logistical considerations. Package-1 includes installation of pumping machinery, creation of feeder mains, surge protection devices, instrumentation, and IT-related works.
Package-2 will cover a part of the ring main and transmission mains measuring 42.71 km while Package-3 will cover the remaining part of ring main and transmission mains of 40.12 km. The entire `3,100-crore project will be completed before February 2030 and the potential bidder will operate and maintain the RMS for 10 years, as per the document.
The RMS will comprise feeder mains (pipelines from water sources) with a total length of 16 km and ring main pipeline with a total length of 98 km. The transmission mains will run for 115 km. The water manager will utilise existing feeder mains (75% of 16 km), ring main (7% of 98 km) and transmission mains (44% of 115 km) in the project.
As part of the project, drinking water sources such as lakes and desalination plants will be interlinked by a ring pipeline, which will ensure uniformity in water supply across the city. “The tenders will be finalised once the MCC is lifted,” a Metro Water official added.