After facing a delay of almost a year, BMC all set to restart its work on the Veravali-Powai-Ghatkopar water supply tunnel. The civic body will be getting a new Tunnel Boring Machine (TBM) soon, and the project will now cost around Rs 300 crore including the cost of purchasing the new TBM.
To augment the water supply in the western and eastern suburbs of Mumbai and strengthen the water line network, BMC’s water supply department is constructing a 6.6-km tunnel from Veravali to Ghatkopar. For this, in August 2019, a TBM – of German make was brought from Herrenknecht tunnelling systems. However, the project was stuck for almost a year after TBM got stuck in the same tunnel it was drilling near Powai. During the monsoon last year, the tunnel was flooded and the stuck TBM is now covered by muck all around.
"Mumbai is reclaimed the city, the soil strata is unpredictable. Now, we have better information about the soil strata that exists at the alignment of the tunnel. The previous TBM was drilling soil strata made of Pyroclastic Ash, which is very loose in nature. We had approached all TBM experts even globally to find a way out. Finally, we have now decided to appoint a new contractor and restart the work and try to cover up the time we have lost. It is a huge challenge before us," said a senior BMC official.
According to BMC officials, the decision was taken after series of meetings with civil engineers and experts from IIT-Mumbai. The civic body is planning to appoint a new contractor who will be getting the new TBM to complete the remaining tunnelling and drilling.
The civic officials said that the work has increased and the new deadline for the completion of the project will now be 2024 and the overall cost for the remaining work of tunnelling including the purchase of the new TBM is estimated to reach Rs 300 crore.
"The work includes the purchase of a new TBM, construction of a new launching shaft to lower the TBM ahead of the location where the old one is stuck, completing the remaining excavation work and then removal of the stuck machine, which is our priority," added the official.
In January 2012, a contract of Rs 183 crore for constructing the Veravali-Powai-Ghatkopar water supply project was awarded to Patel Engineering Limited with a 48-month deadline. There are two arms of the tunnel, Powai being the centre point.
Officials said with the appointment of this new contractor, the project deadline will be extended for the third time since 2012. “The construction of the remaining tunnel and removal of the stuck machine is expected to take at least three years. The earlier deadline for the project was 2016. After that two more extensions were done, including this one," said another BMC official.