Changing City: An underwater water supply tank in Malabar Hill to meet South Mumbai’s water demand – The Indian Express

The project:

To augment the water supply in South Mumbai, the Brihanmumbai Municipal Corporation (BMC) is set to create an underwater water supply tank in Malabar Hill.

About the project:

To improve the water supply, the BMC is set to reconstruct an existing underground water reservoir with increased capacity. Built in 1887, this 135-year-old reservoir is the city’s first water-holding tank. Currently, this reservoir supplies water to the entire South Mumbai area, covering five municipal wards starting from Malabar Hill and Nepean Sea Road, to Nariman Point and Cuffe Parade in the southernmost tip of the city.

Location and specification of the proposed plan:

The reservoir is located at a hillock just beneath the surface of Hanging Gardens and the current capacity of this tank is around 150 million litres per day (MLD). Over the years, the population and demography of the entire city, including South Mumbai, have changed, leading to increased demand for water supply, as a result, the BMC has now decided to increase this capacity to 190 MLD.

Significance of this project:

The decision of reconstructing this tank was taken up following a structural audit that was carried out in 2019. The BMC has divided the work into five different phases and the first phase of the construction works will start in early 2023.

How the project will be carried out:

Since the existing reservoir is the sole source of water supply to South Mumbai, the BMC will not shut it down entirely and the demolition of the existing reservoir as well as the construction of the new one will be carried out simultaneously.

There are seven different chambers for storing water inside the reservoir. In the first phase, the first chamber will be emptied and its water will be transferred into its neighbouring chamber to ensure that there is no crisis in supply, and after that, demolition and reconstruction will begin. Similarly, in each phase, the engineers will demolish and reconstruct a specific chamber of the reservoir.

How it will help Mumbaikars:

The Malabar Hill reservoir supplies water to Mumbai’s A, B, C, and E wards. These areas used to house the maximum proportion of the entire city’s population till the early 20th century as the suburban belt was not suitable for human habitation then. Currently, the water is being supplied to the reservoir from Vaitarna lake, which is one of the seven lakes that supply water to Mumbai.

But considering the change in population, rapid industrialisation and demography, the water demand has increased. Therefore, reconstructing this tank will only help Mumbaikars get more water.

Present status and construction period:

The construction work for this tank is yet to begin even though the BMC has finalised the contractor and issued the work order. The civic body is awaiting several no-objection certificates. Officials said that they may get approvals early next year after which, construction will begin.

Cost:

The cost of this project has been earmarked at Rs 400 crore.

Authority Speak:

“The primary objective of taking up the rebuilding works is to ensure that the crisis of water shortage is resolved. The population level and overall demography of South Mumbai has changed drastically throughout the past decades, which eventually has led to a demand in the daily water supply as well,” said a senior official from the water supply project department.

“This project is an engineering marvel since the construction will be very difficult and challenging as it will be taken up in hilly terrain and will require underground digging as well. Therefore, we are keeping a flexible time frame since work will be carried out in limited capacity during monsoon,” the official added.