Urban News

“Some reverse operations have to be done,” said a senior official associated with the repairs. The equipment, air ventilation system and lights have to be removed and the tunnel has to be cleared, the official said.

“We had attached 60 lights in the tunnel as it was very dark inside,” said the official. “Also oxygen pipes and the ventilation duct fixed to undertake the repair work has to be removed.”

There were also some steps that had been constructed under the trolley used for getting into the tunnel which have to be removed, he added.

Besides, the tunnel has to be charged before water supply can be restored. About 21 million litres of water was pumped out to carry out the repairs. This has to be released into the tunnel again. The charging has to be done gradually or else sudden increase in pressure may cause damage to the tunnel, the official said.

Finally, water supply system will have to be shifted from the old system through the Borivali reservoir to the Malad tunnel , which will take around two days.

The tunnel was breached in February when some residents illegally dug a borewell above it. Repairs began on May 2 and specialists from Hindustan Construction Company (HCC), appointed by the civic body for the work, made arrangements to send engineers into the tunnel to plug the damaged point.  The civic body had detected the 6-inch-wide, 2-metre-long puncture 74 metres below the ground.

This was a first-of-its-kind repair done anywhere in India, the officials said. The tunnel, from Bhandup Complex to Liberty Garden, supplies water to Malad, Goregaon, Kandivli and Jogeshwari that are now facing water cuts.