Improved flood prevention measures around Orchard Road from this month

SINGAPORE – Two new flood protection measures to help divert stormwater and reduce flood risks around Orchard Road will go into operation this month, national water agency PUB announced on Friday (Sept 28).

The completion of the Stamford Detention Tank (SDT), which began construction in 2013, will allow for the temporary storage of up to 38,000m3 – or 15 Olympic sized swimming pools – of stormwater from the drains on Holland Road during heavy rainfall.

"The excess stormwater will flow from the drains into a weir chamber where a pair of inlet pipes will then channel the water into the SDT by gravity," said the PUB.

At its max capacity, the PUB said that it will take about four hours to empty and prepare the tank for the next heavy rainfall.

Once the rain subsides, water levels in the Holland Road drains will fall. This allows the water stored in the tank to be pumped back into the drains, which leads to the Stamford Diversion Canal (SDC).

The canal, which started construction in 2014, will divert stormwater from upstream areas such as Holland Road and Napier Road areas, into the Singapore River. The water will be discharged into the Singapore River through two underground tunnels of 4.5m in diameter and drains, before leading into the Marina Reservoir.

"Previously, stormwater from these areas was channelled directly into Stamford Canal. The SDC will now be able to relieve Stamford Canal of a portion of stormwater," said the PUB.

The SDC runs for two kilometres underneath Tanglin Road to Grange Road, across to Hoot Kiam Road, off Kim Seng Road and to the Singapore River.

Besides the new SDT and SDC, other flood prevention measures around Orchard Road have also been implemented, such as raising the road from Orange Grove Road to Cairnhill Road by an average of 30cm, introducing a lining to smoothen the walls of Stamford Canal to channel stormwater more quickly and working with building owners along Orchard Road to install flood barriers.

Intense rains in 2010 and 2011 had caused floods in Orchard Road as the Stamford Canal, which stretches 4.7km under Orchard Road shopping belt from Tanglin to Marina Reservoir, could not cope with the heavy rain then.