Flood-prevention systems to be tightened at six MRT stations

By Royston Sim, The Straits Times, 28 Feb 2012

THE Land Transport Authority (LTA) is taking steps to beef up flood-prevention systems in six downtown MRT stations.

The stations are all sited in low-lying areas with track records of flash floods, but have themselves never been flooded.

They are Raffles Place, City Hall, Tanjong Pagar, Novena, Little India and Orchard.

A tender called this month said the works will include the installation of flood-barrier systems at the stations, the sealing of glass panels and other openings to make them watertight, and the raising of the height of vent shafts and firemen's staircases. The works are to be completed within a year.

Contractors are expected to design and install two types of flood-barrier system 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 they take two people no more than 15 minutes to set up.

When contacted, an LTA spokesman said: 'All MRT stations were designed so that the station entrances are high enough to accommodate potential flooding should it occur in lower-lying areas.'

But as a result of the ongoing monitoring of the MRT network, the LTA has decided to take additional measures for these stations, given their locations, he said.

No MRT station has ever been flooded, and the works are preventive in nature.

Associate Professor Susanto Teng of Nanyang Technological University's School of Civil and Environmental Engineering said that while MRT stations are flood-proof for now, there is no guarantee they will remain so in the future.

He said: 'It's good to be ahead of the problem. It's much cheaper to prevent something than to try and fix it when something happens. By then, it's too late.'

He noted that the systems of the kind being called for in the LTA tender are used in cities in the United States, where it is impractical to build permanent flood barriers.

Commuter Chua Wei Yang agreed that it was a good move to make MRT stations such as Orchard more flood-proof.

The 25-year-old associate engineer said: 'The station is underground and there could be a lot of damage if it is flooded.'