Committee formed to prevent flooding incidents on MRT system

This article is more than 12 months old

It will study and put in place long-term measures to prevent repeat of such MRT disruptions

Almost two months after flooding disrupted services on the North-South MRT line for 20 hours, a committee has been formed by the Land Transport Authority (LTA) and water agency PUB to prevent such incidents from recurring.

This was announced by Coordinating Minister for Infrastructure and Minister for Transport Khaw Boon Wan yesterday.

Speaking at the fifth Joint Forum on Infrastructure Maintenance, Mr Khaw said the new committee will study long-term measures "beyond our generation" and put them in place.

"The PUB/LTA Standing Committee will institutionalise our lessons and hard-earned experiences, lest they disappear with us at the crematorium."

In response to queries, the LTA and PUB said the committee will "assess the resilience of the flood protection measures for critical transport infrastructure against climate change, and review the emergency preparedness plans and collaborations between LTA, the public transport operators and other agencies during joint exercises."

Though they did not provide details such as who will head the committee, the two agencies said the committee will put up an "annual comprehensive review", to be submitted to the Transport Minister.

Mr Khaw told the forum - organised by the LTA and PUB as well as rail operators SMRT and SBS Transit and held at the Environment Building in Scotts Road - that the committee stemmed from a suggestion made by former PUB chairman Tan Gee Paw, who said in an e-mail to the PUB and LTA on Nov 12 that such a committee could meet every six months to "keep track of progress and take up new developments in tunnel flood prevention".

In the 1960s, Mr Tan - who was also selected by Mr Khaw two years ago as his rail transformation adviser - was instrumental in drawing up the Bukit Timah Flood Alleviation Scheme, which helped ease flooding in the Bukit Timah catchment area.

The Oct 7 flooding incident will be remembered for a long time; it better be.Coordinating Minister for infrastructure and Minister for Transport Khaw Boon Wan


In his e-mail, Mr Tan had noted: "In Taipei, where they have to deal with typhoons, their tunnel portals are protected with sluice gates to completely seal the tunnels against flooding, and of course all rail services are suspended during typhoons.

"We may never experience typhoons but we will experience heavier rainfall periods, as the typhoon belt shifts southwards and we sit at the periphery of these typhoons."

Mr Tan suggested Singapore could follow Taipei's example in building sluice gates for new tunnels, noting that retrofitting sluice gates on existing lines is "near impossible".

On Oct 7, flooding in the MRT tunnel between Bishan and Braddell stations disrupted services on the North-South Line and led to a section of the line being shut down overnight.

Mr Khaw said at the forum: "The Oct 7 flooding incident will be remembered for a long time; it better be."

He added that the incident was not a failure of engineering but of organisational management at SMRT.

However, Mr Khaw said he had "full confidence" in SMRT chairman Seah Moon Ming.

Mr Seah announced yesterday that he was stepping down as chief executive of Temasek unit Pavilion Energy to focus on his SMRT role.

LTA says Bishan MRT station flood 'entirely preventable'

The flooding of the MRT tunnel near Bishan station on Oct 7 was "entirely preventable" had SMRT carried out proper maintenance, the Land Transport Authority (LTA) said yesterday, releasing the findings of its investigation.

Rail operator SMRT said it accepted full responsibility for the incident in which flood waters reached up to a metre in depth in train tunnels and led to a section of the North-South Line being shut down for 14½ hours.

The service disruption affected 231,000 commuters.

Independent laboratory tests by Singapore Test Services (STS) found the individual components of the Bishan storm water pump system - part of a system to prevent tracks from flooding - were not defective.

All five float switches and the pump motor control panel were working. Three storm water sump pumps - each capable of removing 85 litres of water per second - at Bishan station were also found to be in working condition, as they could still be activated manually following the incident.

The LTA said the flood protection measures were "more than adequate" to handle the Oct 7 rainfall.

Further STS laboratory tests found three possible reasons the system failed to prevent the flooding.

One was that the lowest float switch, which would have activated the storm water sump pumps, could have been obstructed by accumulated silt and sludge in the pit.

Another was that floating debris in the pit could have impeded the normal functioning of the float switches.

Thirdly, an SMRT maintenance team - which repaired the pump system on July 13 after reports of frequent pump trips - could have left the pump controls in manual mode.

LTA said that it could not say definitively which of three was to be blamed and that any combination of these could have led to the flooding of the tunnel.

"Nonetheless, all three possible failure scenarios could only arise as a result of a lack of proper maintenance, audits and supervision," it added, noting that silt, sludge and debris had to be cleared from the pit after the incident.