Anti-flooding measures at 11 more MRT stations

Move seen as preventive and follows earlier steps at 6 downtown stations
Royston Sim Straits Times 30 Jul 12;

THE Land Transport Authority is taking steps to flood-proof more MRT stations.

It called a tender earlier this month to beef up flood prevention measures at 11 MRT stations, several months after it did the same for six downtown stations.

The 11 stations up for enhancement works this time are: Braddell, Toa Payoh, Boon Keng, Somerset, Outram, Tiong Bahru, Bugis, Lavender, Bishan, Marina Bay and Changi Airport.

The works will include installing flood-barrier systems at the stations, sealing glass panels, vent shafts and other openings to make them watertight, and raising escape staircases.

Contractors are expected to design and install two types of flood-barrier systems at several points in each station - a manual stackable type and a swing-type which stays open during normal times.

Both systems must be designed to be watertight when flood waters are below 1.5m - the height of the flood barriers.

The flood barriers should be made of lightweight aluminium panels, said the LTA in its tender documents.

The stackable barriers must also be made so user-friendly that two people will take no more than 15 minutes to set them up.

A spokesman for the authority said: 'All MRT stations and associated structures... were designed such that the entrance and crest levels are high enough to accommodate potential flooding in lower lying areas.'

Still, the authority has decided to take additional measures to enhance the flood prevention capability of selected stations given their locations, he said.

This follows an earlier contract to flood-proof six downtown MRT stations.

That project was awarded to Sigma Builders for $2,228,776.

Those six stations - Orchard, City Hall, Raffles Place, Tanjong Pagar, Novena and Little India - are all sited in low-lying areas with track records of flash-floods, but have themselves never been flooded.

Similarly, works at all 11 stations in this second phase are preventive in nature. No MRT station has ever been flooded.

Manually-operated full-height sliding barriers will also be installed at Tiong Bahru and Bugis stations.

The LTA spokesman explained that this was due to both stations' concourses being located below the lowest level of adjacent buildings.

Work on the first six stations will be completed by the middle of next year, while the next 11 stations should be outfitted by the third quarter of 2014.

Assistant professor Vivien Chua, who teaches in the Department of Civil and Environmental Engineering at the National University of Singapore, said it is a good strategy for the authority to take preventive measures.

Temporary flood barrier systems are more reliable in holding back floodwater compared to sandbags, and are also resistant to seepage, she said.

She added that they are 'also cost-effective solutions compared to the economic cost of flood damage and the inconvenience which might result from flooding at the stations'.

Mr Kevin Kho, a 51-year-old engineer with more than 25 years of experience, said: 'As the saying goes, a stitch in time saves nine. It's more cost-effective to have good preventive measures in place.'