Singapore's first underground service reservoir (USR), built on low ground, is located under Bidadari estate.

The USR is national water agency PUB's solution to overcoming the country's land constraints and to "ensure the resiliency of our water system", Minister for Sustainability and the Environment Grace Fu announced at the joint opening of the Singapore International Water Week and CleanEnviro Summit Singapore on Jun. 19.

What is a service reservoir?

Service reservoirs store drinking water from PUB's treatment plants before it is piped to consumers, and serve as a buffer against daily fluctuations in water demand.

The over 10 service reservoirs that currently exist are all built on high ground, allowing water to flow to consumers via gravity.

This eliminates the need for pumping, as well as the energy required for it.

The current service reservoirs also include NEWater service reservoirs for industrial customers.

Serving Bidadari residents

The Bidadari USR is a pilot project to test the concept of an underground service reservoir within a new housing estate.

During the master planning of the new Bidadari estate, PUB stated that it recognised the opportunity to testbed this concept.

Additionally, the construction of the USR has to be tied in with new developments.

The USR will enable PUB to augment the estate's water supply during peak periods of water demand, such as the morning and evening, without the need to construct new water pipelines.

Comprising a pumping station and two water tanks, the Bidadari USR has a capacity of three Olympic-sized pools of potable water.

Potable water from high ground service reservoirs will flow into the USR's water tanks during off-peak hours, and the USR will supply water to homes at Bidadari estate via five pumps, which will maintain good water pressure during the peak hours of water usage.

This means the USR will serve around 8,872 flats in 12 Build-to-Order (BTO) developments within the estate.

Operations at Bidadari USR are fully automated and can be monitored from PUB’s Joint Operations Centre, according to PUB spokesperson Alfred Chan, the lead engineer for the construction of Bidadari USR.

Saving land

The Bidadari USR is constructed almost entirely underground, save for the pumping station, which occupies around 700 sqm of land within the estate.

Meanwhile, the land above the two underground tanks has been integrated with the 10 hectare Bidadari Park.

As such, the surface footprint of the USR is only about a third of a typical service reservoir, allowing PUB to save around 1,500 sqm of land.

Like other service reservoirs, the Bidadari USR is unmanned, and is controlled by a centralised system.

The reservoir is expected to be operational within the third quarter of 2024.

Top photo from PUB and Hannah Martens