Underground reservoir to serve Bidadari residents
Beneath a green field at Bidadari Park, at a depth of about two basement carpark levels, lies an underground reservoir that will supply water to the new neighbourhood from the third quarter of 2024.
Holding three Olympic-sized swimming pools worth of treated drinking water, the $27 million Bidadari underground service reservoir (USR) – the first of its kind in a housing estate – will boost the main water supply to about 8,800 homes in the estate during peak periods to ensure users enjoy good water pressure.
Like the 10-plus other service reservoirs in Singapore, it also serves as a back-up during emergencies or disruptions to PUB’s main water supply. These service reservoirs are not to be confused with catchment reservoirs such as MacRitchie and Bedok, which are among the 17 scattered across the island to collect rainwater that is subsequently treated.
The Bidadari USR, built by national water agency PUB at the site of the former Mount Vernon Columbarium, has two large underground tanks – each about 6.5m high – to save on surface space and keep the surroundings unmarred.
Just a pumping station above ground, occupying a 700 sq m plot of land, hints at its existence. The USR was designed to be largely unmanned, with an automated control room and five centrally operated pumps.
During off-peak hours when household water demand is not high, the two tanks will be filled with potable water from existing service reservoirs such as Bukit Kalang Service Reservoir.
Other service reservoirs are sited on high ground such as Fort Canning – built in 1929, it is the only other underground service reservoir – and Mount Faber, to leverage gravity to channel water to homes and offices.
The Bidadari USR is currently undergoing commissioning and testing, and is expected to be operational in the third quarter of 2024.
The completion of the Bidadari USR was announced by Minister for Sustainability and the Environment Grace Fu on June 19 at the joint opening of the biennial Singapore International Water Week and CleanEnviro Summit Singapore conferences.
“It will help fortify water supply to meet the water demand of present and future Bidadari residents,” she said at the Marina Bay Sands Expo and Convention Centre.
The Bidadari estate will have about 10,000 homes comprising both public and private housing. As at February, more than 70 per cent of the 8,872 Housing Board flats there have been handed over to their owners, while the remaining flats are on track to be completed by 2025.
The concept of having a reservoir which optimises land use and is integrated with a park in the estate was announced in 2013.
“This approach has enabled PUB to save about 1,500 sq m of space by integrating the land above the water tanks with the adjacent Bidadari Park,” the agency said.
But the USR’s construction, which started in 2020, came with its own set of challenges. Earth had to be excavated to a depth of 9m, but intense rain inadvertently turned the excavation site into a pool, halting work until the water drained.
New developments to support the Singapore’s growing urban population and economic sectors may see more service reservoirs being built.
PUB said: “With Singapore’s water demand projected to nearly double by 2065, Singapore’s water supply infrastructure, including our water treatment plants, service reservoirs and supply pipelines, will require continual investment and expansion.”
The construction of a USR has to be tied in with new developments, said Mr Alfred Chan, lead engineer at PUB’s Water Supply (Network) Department.
The 10ha Bidadari Park’s Alkaff Lake, slated for completion in late 2024, will serve as more than a scenic recreational feature for the neighbourhood. It will also be a stormwater retention pond to prevent flash floods from occurring in surrounding residential areas.
On sunnier days, residents can enjoy Alkaff Lake’s terraced wetlands and cascading creek.
On June 19, Ms Fu also announced that PUB has launched a tender for a floating solar farm at Pandan Reservoir.
The system will be completed in 2028 and have a capacity of 55MW-peak – enough to power 16,000 four-room HDB flats.
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