Mumbai: BMC’s ambitious plan to connect Mumbai’s first seawater desalination plant at Manori with the city’s water distribution network through a 7.2-km underground tunnel came under scrutiny in the civic standing committee on Thursday, with corporators raising concerns over water quality, the tendering process and technical aspects of the project. The project proposal, however, was passed eventually.The civic administration had sought approval to award the Rs 2,241.3-crore contract to Afcons Infrastructure Ltd for the design, construction, operation and maintenance of the tunnel and associated infrastructure. The work is expected to begin next month and be completed in 45 months, with the project targeted for commissioning by December 2029.The tunnel will form a crucial link between the upcoming desalination plant at Manori and Mumbai’s existing water supply network. It will run from Manori to Charkop and further to the existing shaft at Mahavir Nagar in Kandivli, largely beneath the Gorai creek. The 3.2-metre finished-diameter tunnel will initially carry 200 MLD of desalinated water but has been designed to accommodate a future capacity of 400 MLD.BMC officials said two tunnel boring machines (TBMs) will be deployed simultaneously to expedite construction. The project includes a shaft at Manori, where water from the desalination plant will enter the tunnel, a new shaft at Charkop, and integration with the existing Mahavir Nagar shaft. Officials clarified that no water will be drawn out at Charkop, with the tunnel serving only as a transmission link.During the discussion, Yashodhar Phanse, Shiv Sena (UBT) corporator, questioned whether the quality of desalinated water would match that of water supplied from the Bhandup water treatment complex. “We are in favour of the project, but our staff should also be trained to execute such specialised works,” he said.Congress corporator Ashraf Azmi said the desalination plant and the tunnel should have been tendered together to avoid delays. “Also why did the BMC keep 16% as contingency fund for the project?,” said Azmi.BJP corporator Prakash Darekar said Mumbai’s water shortage needed a permanent solution and supported the project.Congress corporator Tulip Miranda expressed concerns over blending desalinated water with treated lake water coming from the Bhandup water treatment plant. “People have raised concerns about hair dryness and breakage because of minerals and chlorine in desalinated water. What steps will the BMC take to ensure there is no impact on citizens to whom this water is supplied?” she asked.Replying to the queries, additional municipal commissioner Abhijit Bangar said the quality of desalinated water would be matched with that of water supplied from the existing Bhandup water treatment complex before it enters the city’s distribution system.“The tunnel is technically complex. Of the 7.2 km length, about 5.1 km will have RCC lining while the remaining stretch will have mild steel lining with M30 grade concrete protection. Strict penalties have been built into the contract for any leakage,” Bangar said.He said the tunnel alignment and desalination project had been planned together during the detailed design stage. The desalination project was floated as a global tender because of its specialised nature, while the tunnel work was tendered separately.Bangar also defended the 16% contingency provision in the project cost, saying it accounted for annual price escalation of 4% over the construction period and was in line with industry norms.He added that while the desalination plant’s first phase would produce 200 MLD, the transmission infrastructure had been designed for an ultimate capacity of 400 MLD to meet Mumbai’s future water demand.
