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19 June 2024 – 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. In land-scarce Singapore, an innovative planning approach is also needed to overcome our space constraints and ensure the resiliency of our water system.

2   The new Bidadari estate houses Singapore’s first underground service reservoir built on low ground. The Bidadari Underground Service Reservoir (USR) was planned as a project to test the concept of an underground service reservoir within a new housing estate to enhance the water pressure of the pipeline network and manage peak hour water demand.

3   Comprising a pumping station and two water tanks with the capacity to hold a combined equivalent of three Olympic-sized swimming pools of potable water – the Bidadari USR was first proposed by PUB during the master planning of the Bidadari estate, as an innovative method to integrate the facility with the estate’s infrastructure without having to construct new water pipelines amid other competing utilities and services. It is an example of how water demand is met through a collaborative planning approach with multiple agencies, i.e. the Urban Redevelopment Authority (URA), Housing & Development Board (HDB), and the National Parks Board (NParks).

4   The surface footprint of the Bidadari USR is about one-third that of a typical service reservoir of this capacity. Jointly constructed by PUB and HDB, the facility is almost entirely underground, with only the pumping station occupying an approximately 700 sq m plot of land within the Bidadari estate. This approach has enabled PUB to save about 1,500 sq m by integrating the land above the water tanks with the adjacent Bidadari Park.

External view of Bidadari USR pumping station (left) and the interior of one of the underground water tanks (right)

Design and Functions

A photo of Island Service Reservoir, that stores potable water

5   Service reservoirs store drinking water from PUB’s treatment plants before it is piped to consumers and are a crucial part of Singapore’s water supply network. They serve as a buffer against daily fluctuations in water demand. Existing service reservoirs are built on high ground due to the need to maintain stable and consistent pressure throughout the network, so that water flows to customers via gravity without the need for pumping. PUB currently operates over 10 such service reservoirs, including NEWater service reservoirs for industrial customers.

6   In contrast, the Bidadari USR was constructed in tandem with a new estate to boost water pressure in the network. It supplies water to homes via up to five centrally operated pumps. These pumps operate during peak water usage hours to maintain good water pressure in the water network, fortifying water supply to customers in the new estate. During off-peak hours, the USR will be filled up with potable water from other high ground service reservoirs to ensure adequate water supply for subsequent peak hour usage.

Underground water pumps (left) and the USR’s automated control room (right)

Using smart technology to operate Bidadari USR

7   Operations of the USR are controlled by a centralised system, reducing the need for manual operation. This is similar to other service reservoirs.

8   BIM (Building Information Modelling) technology was used for the 3D-modelling and construction of the USR. Compared to conventional 2D models, this technology helped PUB visualise the layout of the USR structure more efficiently, especially with complex layers of pipeworks within the USR.

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