Exclusive | Mumbai: More trees might be saved at Malabar Hill reservoir

Abandoning the plan to build an additional tank with a 90 million litre capacity to reconstruct the 144-year-old Malabar Hill reservoir in phases, the BMC's hydraulic study suggested that the new reservoir can be reduced to 34 million litres to repair the reservoir. The smaller reservoir will occupy less space and ultimately require fewer trees to be cut down. The earlier plan had required the removal of over 389 trees.

The issue of reconstructing old reservoirs and building additional ones has been ongoing for over a year. After a protest by residents last year, followed by expert panel visits, two different reports, and a final report by IIT Roorkee suggested various ways to reconstruct or repair the reservoir. It is now almost clear that the BMC has opted to repair the reservoir in phases, which requires an additional tank, instead of reconstructing the entire British-era structure.

Members of the panel examining the reservoir on December 7, 2023. File pic

IIT Roorkee recently submitted its report on the Malabar Hill reservoir, suggesting that an additional tank with a capacity of 52 million litres is required to repair the reservoir in phases. The IIT Bombay experts had recommended reconstruction and additional tanks of the same capacity in their report in March, but the suggestion wasn't accepted by residents and experts. BMC officials carried out a hydraulic study to see if the size of the additional tank could be reduced by increasing the number of cycles of water filling into the tank.

"The current capacity of the tank is 80 million litres, which gets filled thrice a day to supply 240 million litres of water. IIT Roorkee recommended the size of an additional tank based on the information on water capacity and the cycle of water supply given by the BMC. So after the report, the BMC conducted a hydraulic study that concluded the size of the tank could be reduced to 34 million litres by increasing the number of supply cycles. We have discussed the pros and cons of it but haven't finalised the size yet," said Abhijeet Bangar, additional municipal commissioner. He added that the location of the tank cannot be changed as it is part of the distribution system, and the water supply is based on gravitational force.

The BMC initially planned to demolish and reconstruct the reservoir supplying water to south Mumbai by constructing a tank with a 90 million litre capacity, which required the transplantation of 200 trees and the axing of 189 others. "Now the new size is almost one-third of the earlier tank, so it will obviously occupy less space and a few more trees can be saved by changing the shape (increasing depth)," said another BMC official.

144
Age of the reservoir in years

What happened so far

. After a protest from citizens over the removal of 389 trees, a committee was formed on November 8, 2023, comprising residents and IIT Bombay professors.
. Citizens' representatives submitted a report in January favouring functional repairs over demolition.
. In March, IIT experts recommended constructing a new tank to facilitate reservoir repairs or reconstruction.
. The BMC invited IIT Roorkee experts, who suggested repairing and adding a new tank with a 52-million-litre capacity.
. The BMC conducted a hydraulic study and now suggested building a tank with a 34 million litre capacity.

Malabar reservoir facts

. Comprises two tanks and five sections.
. Has a combined storage capacity of 35.35 million litres in sections 1A, 1B, and 1C.
. Total storage capacity in sections 2A and 2B is 39.17 million litres.
. Either 1A, 1B, and 1C together or 2A and 2B must be closed for this repair work.