Underground tank to prevent flooding in low-lying Jalan Besar area completed

Straits Times

18 hours ago

Located next to Rochor Canal, the Syed Alwi Pumping Station is designed to divert storm water from the upstream of Rochor Canal into an underground tank. ST PHOTO: BRIAN TEO
SINGAPORE – The low-lying Jalan Besar area and parts of Little India are now better protected against floods with the completion of a new pumping station with an underground tank along Syed Alwi Road.
Located next to Rochor Canal, the Syed Alwi Pumping Station is designed to divert storm water from the upstream of Rochor Canal into an underground tank.
The water is then pumped out of the tank – which is able to hold about 9,300 cubic m of water, or about the total capacity of four Olympic-size pools – into a downstream section of Rochor Canal during and after storms.
This ensures that storm drains, which collect rainwater run-off from the Jalan Besar area, are not overwhelmed during intense rain when the water level in the canal is high.
The completion of the underground tank was announced by Minister for Sustainability and the Environment Grace Fu in a recorded address at the 2025 Singapore International Water Week Spotlight conference on June 23.
'As ground raising is not possible in (Jalan Besar), the dual-purpose storage and pumping station was conceptualised as an alternative solution to enhance flood resilience,' she said in the video, which was aired at the event held at the Singapore Expo.
National water agency PUB, which built the $33 million pumping station, said it 'forms part of PUB's diverse storm water management infrastructure to strengthen Singapore's flood resilience as climate change brings about more frequent and intense rainfall'.
The fully automated pumping station, which was completed in June, also has floodgates at the Syed Alwi Road drains that shut to prevent backflow of water from Rochor Canal into the Jalan Besar area.
Construction of the Syed Alwi Pumping Station began in 2021, with most of the costs covered by Singapore's Coastal and Flood Protection Fund.
The fund, which was set up with an initial injection of $5 billion in 2020, received an additional injection of $5 billion from Budget 2025, to fund both coastal protection and drainage infrastructure.
Jalan Besar is a low-lying area that experienced flooding from the 2000s to 2010s. The last time it experienced a flooding incident was on Nov 13, 2014, said PUB.
Among the efforts made to combat flooding in the area were the upgrading of drains along Syed Alwi Road and raising road levels in 2014.
Rochor Canal, which runs along Sungei Road and Rochor Canal Road towards Marina Reservoir, was also widened and deepened in 2015 to increase its drainage capacity.
These measures enhanced flood protection in nearby areas such as Veerasamy Road, Hindoo Road and Desker Road.
However, expanding drainage infrastructure and raising ground levels are not feasible for all sites, said Ms Gayathri Kalyanaraman, senior principal engineer for drainage planning at PUB's catchment and waterways department.
'The low-lying Jalan Besar area illustrates this challenge,' she said.
It is not possible to raise roads and buildings in the area, which has many heritage buildings such as Masjid Angullia and the shophouse at 75 Maude Road.
This is where the new pumping station comes in – enhancing the area's flood resilience.
Storm water will accumulate in the underground tank, which is 11m high and has the capacity of four Olympic-sized pools and can hold about 9,300 cu m of water.
ST PHOTO: BRIAN TEO
When the water level in the tank reaches 4.5m, the pumps will be automatically activated to discharge water into Rochor Canal via two outlets. When the water level is below 4m, the water will be discharged by two other smaller pumps into the canal.
ST PHOTO: BRIAN TEO
Two other pumping stations, built in the 1990s, enhance flood resilience in the low-lying Tanjong Katong estate.
Despite its efforts to enhance Singapore's drainage infrastructure, 'absolute protection is not possible, and building community resilience is key', said PUB.
Stakeholders such as building owners and contractors can ensure proper maintenance of internal drainage systems, and implement flood protection measures according to stipulated guidelines to better protect their properties, it added.
Meanwhile, the Syed Alwi Pumping Station has brought more verdancy to the Rochor area, with features like a green roof and green wall. Coming up next to it is an open plaza that will provide a recreational space integrated with nearby Build-To-Order development King George's Heights, which is under construction.
As part of efforts to protect Singapore's coasts from sea-level rise, the Republic has divided its coastline into eight stretches, and is conducting separate studies on them to determine the most suitable ways to protect each stretch from future rising seas.
Where possible, these solutions will be multifunctional, enhancing the environment and supporting better land use, said Ms Fu.
She added that PUB will soon launch a risk assessment study to evaluate eight offshore islands' vulnerability to sea-level rise.
This is an expansion of the work being done on the mainland, and more details will be revealed in a few days.
Additional reporting by Shabana Begum
Join ST's WhatsApp Channel and get the latest news and must-reads.