Following a nine-month study on long-term anti-flood measures, national water agency PUB yesterday announced plans to build an underground detention tank and a 2-km diversion canal, which will ease the load on the Stamford Canal.
Detailed design for the construction tenders of both projects will be conducted this year.
The four-storey high detention tank is set for completion by the end of 2015. It will be built beneath a proposed nursery and coach park at Tyersall Avenue next to the Botanic Gardens. With an estimated capacity of 38,000 cubic metres - or 15 times that of an Olympic-sized pool - it will store excess stormwater from the existing drains along Holland Road. The excess stormwater will be pumped back into the drains for discharge into the Marina Reservoir via the proposed diversion canal after the rain subsides.
Work on the diversion canal is expected to be done by the end of 2017. It will divert rainwater from 38 per cent of the Stamford Canal catchment to the Singapore River.
About 3m to 4m deep, the new canal will run beneath the surface, starting from Grange Road, along Hoot Kiam Road, River Valley Road and off Kim Seng Road to the Singapore River.
As the projects will be up for tender, PUB said it is premature to estimate the cost. Nevertheless, it said the issues of cost and feasibility of solutions had been taken into consideration.
In January, Minister for the Environment and Water Resources Vivian Balakrishnan said in Parliament that building a diversion canal would cost between S$300 million and S$400 million, as he spoke about the possible options to alleviate future floods in the area.
PUB said it will work with the relevant agencies and stakeholder groups, such as the Land Transport Authority (LTA), to minimise disruptions during the construction.
At a media briefing yesterday, PUB Director of Catchment and Waterways Tan Nguan Sen said: “There will be operations where part of the road will be diverted, but the diversion will ensure that the number of lanes on the road will be maintained.”
Speaking to TODAY, Professor Chan Eng Soon, who chaired an expert panel on drainage design and flood protection measures, said the duration of the construction of the diversion canal was understandable. He said: “You’re looking at the diversion of a significant amount of rainfall runoff, so it’ll be quite a sizeable canal to build.
“Naturally, the construction will need to take time.”
PUB has previously rolled out several drainage improvement projects in the area to alleviate flash floods including the removal of sections of the NEWater pipeline in the canal and the smoothening of the canal wall with polymer lining.
Owners of buildings along Orchard Road, such as Lucky Plaza, Tanglin Mall and Wisma Atria, have also put in place measures to improve flood protection. For example, Wisma Atria has raised its platform to prevent floodwater from entering its basement.
Orchard Road Business Association executive director Steven Goh said that last week, PUB had informed his association of its plans.
Welcoming PUB’s latest initiatives, Mr Goh acknowledged PUB’s efforts in addressing the issue as well as engaging the stakeholders. “Right now, even without the canal, they are already trying to improve the flow of the water by installing the polymer lining in different pockets of Orchard Road,” he noted.
