BMC begins soil testing for planned Malabar Hill tank

MUMBAI: BMC has begun soil investigation ahead of the proposed 52-MLD (million litres per day) reservoir project at Malabar Hill, marking the next step in its plan to create an alternative to the ageing underground water reservoir while attempting to preserve the iconic Hanging Gardens above it.Civic officials said the geotechnical investigation will help determine the nature of the rock strata, soil stability, foundation depth and structural feasibility of the proposed elevated reservoir structures. “Currently, borehole drilling and subsurface testing are being carried out across multiple locations within the proposed reservoir site and adjoining utility areas. This is like an X-ray of the ground. We need to understand the type of rock, soil stability and depth before finalising the structural design,” an official said.A civic official said, “We will need approval from the executive body once the design is finalised. Thereafter, work at the site will begin. Notices regarding the 76 trees likely to be impacted will also be issued later this year.”According to engineers, approximately one borehole is planned for every 100 sq m at the tank site, apart from separate investigations near valve chambers and utility sections, which will be carried out in the coming months. Some boreholes are expected to extend nearly 20 metres below ground level to study subsurface conditions. Officials said the detailed engineering design, currently underway, will include foundation design, structural layout, column positioning and an assessment of load-bearing capacity.BMC is also planning a 2,200 sq m garden atop the proposed ground-plus-twostorey alternate tank structure. Officials, however, said that any garden developed above the reservoir would require tree species whose root systems do not penetrate deeply into the masonry and water-retaining structure. Officials indicated that the proposed garden would attempt to create a “level match” with the elevated Hanging Gardens adjacent to it, so that the area’s existing landscape character can be retained as far as possible.The Malabar Hill reservoir, one of Mumbai’s oldest water infrastructure assets, dates back to the British era and is located beneath Hanging Gardens.