Mumbai: Century-old arch drains set to get geopolymer lining

An arch drain made of bricks. Some of these century-old drains have collapsed due to wear and tear, leading to road cave-ins

The BMC has finally found a solution to prevent road cave-ins caused due to old arch drains. The civic body has invited tenders to line the century-old arch drains in south Mumbai with geopolymer which, officials claim, will improve the strength of the drain for 50 years. The tender was announced on December 27, 2022 and the last date of submission of bids is January 17, 2023.

The city has, in the past, witnessed several cave-ins on roads due to the collapse of underground arch drains. An official from the Brihanmumbai Municipal Corporation said that it was difficult to replace this century-old underground network and the same would be more costly too. "After a study, we have decided to strengthen the system with geopolymer lining at a cost of Rs 415 crore. We have invited tenders for the 14.28-kilometre arch drain network in the island city," the official said, adding, "Once this is done, we will consider the same in the suburbs too. The city has a 32-km arch-drain network."

The geopolymer lining will help prevent leakage in the drain and stop road cave-ins. "As this project is trenchless, it will not affect road traffic and congestion," the official added.

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According to the tender document, the contractor will work on geopolymer lining and will also have to work on utility shifting, diversion of flow for enabling the construction, dewatering, utility diversion and thorough desilting of the arch drain. The contractor will also be responsible during a five-year comprehensive maintenance period after the completion of the civil work. During this period, the contractor has to carry out cleaning, desilting and a CCTV survey of the same between February 1 and May 31 every year as and when directed by the engineer in-charge of the maintenance period.

These arch drains, made of brick masonry at a depth of five to 15 feet underground, have become dilapidated because of wear and tear over decades, said BMC officials.