The Brihanmumbai Municipal Corporation (BMC) will be constructing a 8.48 km-long water supply tunnel between Dharavi and Ghatkopar, The Indian Express reported.
The tunnel will be constructed underground at a depth of 145-150 metres, with its deepest point at 152 metres at Ghatkopar. The tunnels are laid at a deeper level than pipeline so that they do not get damaged by road or civil infrastructure works.
The BMC is constructing two wastewater treatment facilities (WWTF) at these locations, where recycled water will be transported through the tunnels.
This tunnel will form part of a larger 11.61 km water tunnel network that the BMC is extending from Ghatkopar to Bhandup. Currently, the BMC maintains a 100 km water tunnel network across the city.
Ghatkopar, Parel, and Wadala, located in the eastern suburbs and central parts of the island city, have faced challenges with water supply due to aging pipelines that struggled to maintain adequate pressure in densely populated areas.
The 8.48 km tunnel is estimated to cost Rs 1,989 crore, with the civic authorities issuing the work order for its construction on September 30. Civic officials have stated that the tunnel will be built using a tunnel boring machine (TBM) and will have a diameter of approximately 12 meters.
“The project has been conceived to curb cases of water contamination and manmade leakages. These tunnels will run deep below the surface and the chances of pipelines getting damaged during civic and infrastructure works are minimum. The tunnels will also have a larger diameter, which will lead to improved water pressure since we will be able to supply a higher quantum of water,” a civic official said.
In August, the BMC completed the excavation of a 9.7 km water tunnel between Ghatkopar and Wadala. With this addition, Mumbai’s underground water tunnel network now spans 100 km. Currently, New York holds the record for the world’s longest water tunnel network at 111 km. Mumbai’s first water supply tunnel was laid in 1955, and the network has expanded steadily over the years.