Deluge in Singapore a 'once in 50 years' event

Diversion canal could not cope; drainage work to be sped up, says Yaacob
Amresh Gunasingham & Ang Yiying, Straits Times 21 Nov 09;

THURSDAY'S deluge which submerged parts of Bukit Timah was a 'freak' event that occurs once in 50 years, Minister for the Environment and Water Resources Yaacob Ibrahim said yesterday.

'What happened was very unusual,' he said. 'The intensity was tremendous.'

Shortly after 1pm the skies opened and in the next two hours, almost 110mm of rain fell - almost half the average monthly rainfall for November.

When a diversion canal from the main Bukit Timah canal burst its banks, flood waters rose knee-high, partially submerging ground-floor buildings and cars and causing untold damage.

'We knew the diversion canal was not big enough to take this,' the minister said about the three decade-old canal which stretches more than 3km, from Sixth Avenue to Sungei Ulu Pandan.

It was built in 1972 as part of the Bukit Timah Flood Alleviation Scheme, a major government project aimed at diverting water away from Bukit Timah - a low-lying area with a history of flooding stretching back to the 1930s.

A second diversion canal built in the 1990s near Whitley Road runs into Sungei Kallang and the Marina Reservoir.

The minister said yesterday that plans to widen and deepen drainage networks in the area will be sped up.

PUB, the national water agency, has called for tenders for an engineering consultant to widen the canals in the Bukit Timah area in anticipation of increased stormwater run-off from upcoming developments in the area, a spokesman said.

Construction is expected to start by the third quarter of next year.

Dr Yaacob urged patience as reinforcement work is carried out.

The current north-east monsoon season is usually the wettest time of the year, with almost 48 per cent of the year's rainfall occurring between November and January.

But even thorough planning is not always enough to deal with extreme weather, the minister said.

'It is not possible... to plan for every event. Thursday's weather... occurs once in 50 years. If we design for the largest rainfall or highest tide, then we are going to have huge canals in Singapore.'

The most important thing is to have an adequate drainage system that is continuously upgraded, he said.

Before the canal was built, the area saw about 12 floods a year, with waters rising up to 0.7m. Since then, it remained relatively flood-free until Thursday.

Since the early 70s, more than $2 billion has been spent on building new canals and drains, including the Marina Reservoir, which in the event of a storm can pump 6.3 billion gallons of stormwater out to sea, alleviating flooding in the city area.

It was never used on Thursday as the diversion canal which broke drains into Sungei Ulu Pandan, and the Pandan Reservoir, not the Marina Reservoir, Dr Yaacob noted yesterday.

Speaking to reporters on the sidelines as he sent off a group of haj pilgrims at Changi Airport, the minister promised assistance to those affected, saying: 'We will look to do whatever we can to help.'

Mr T.C. Chua, an engineer who was involved in a project to upgrade the Bukit Timah canal in the 1980s, told The Straits Times that development activity in the Upper Bukit Timah area could have contributed to the floods.

'The clearing of shrubs and trees could increase the surface run-off into the canal as there is no build-up to constrict the flow,' he said.

According to the National Environment Agency, moderate to heavy showers with thunder can be expected in the next few days, mainly in the afternoons.

Damaged cars towed out of carpark
Carolyn Quek & Lim Wei Chean, Straits Times 21 Nov 09;

ONE by one, cars left the Tessarina condominium in Wilby Road yesterday - not driven, but towed to workshops for repairs.

They had been almost fully submerged in water for hours on Thursday after heavy rain rushed down the ramps of the condominium's entrance and into its underground carpark.

PUB contractors worked feverishly through the night to pump out the water, so that the stranded cars, including luxury vehicles such as a Ferrari and a Porsche, could be removed.

The total cost of the damage is not known, but with about 100 vehicles parked inside the 500-lot carpark, it is expected to run into millions of dollars.

The Tessarina's basement carpark was one of two along Bukit Timah Road to be affected by the sudden downpour.

The other carpark, at the 6th Avenue Centre, had four vehicles submerged in water.

The flash floods affected a wide stretch of Bukit Timah: from Coronation Road to Third Avenue; Wilby Road to Blackmore Drive; and the Sixth Avenue junction.

But the Tessarina's basement carpark appears to have taken the worst hit.

Mr C. Lee, a Tessarina resident, watched as his Lexus was towed to a car workshop. He had been overseas on Thursday, returning at 7pm.

'It could have been worse - most of the cars had been driven to work,' said the 43-year-old, who works in finance.

He added that the management should have started advising residents to move their cars as soon as they noticed the carpark was flooding.

The intense downpour saw the water rise to knee-high levels in the Wilby Road area at around 2pm, according to a report from the condominium's managing agent, Chambers International Property Consultants.

Within 20 minutes, the waters were chest-high at the lowest point of the carpark.

The water also filled the lift shafts and flowed into one of two switch rooms in the basement, causing a power outage in a few of five apartment blocks there.

Electricity was restored late last night but the lifts were still being repaired.

Taking no chances, Chambers International will be barricading the switch rooms with sand bags in case of flash floods in the coming days.

Insurers told The Straits Times that only comprehensive motor insurance policies cover flooding. Those that cover third party damage will not protect against flood damage.

But car workshops, which reported a surge in business to have cars towed or repaired, say that whether a waterlogged car can be repaired or not depends on the damage.

A staff member at Nissan Service Centre said that if the water reaches only the bottom of the car, the damage, if any, will be minimal, affecting only the electrical circuit boards and the car's carpet, which can be easily replaced.

Cars submerged in water are almost certain to see more extensive damage to their electronic wiring, not to mention damage to the engine, transmission, seats and more, he added. Repair works for such waterlogged cars can start from $10,000 to $20,000, depending on the make of car and the availability of parts, and can take up to a month, said workshops.

Thursday's floods an event that occurs once every 50 years
Asha Popatlal, Channel NewsAsia 20 Nov 09;

SINGAPORE: A big clean-up is underway on Friday in many areas across Singapore which were flooded due to the heavy rainfall on Thursday.

Environment and Water Resources Minister Yaacob Ibrahim said that work is ongoing to improve the structure of the drains to cope better with such events.

The wet season, due to the northeast monsoon, could well spill over into January. Authorities here said they are planning to upgrade some facilities in phases.

Dr Yaacob said: "I hope the public will have more patience with us because it will take us some time to enlarge those drains. But having said that, it is not possible for us to plan for every event.

"Yesterday's event, I was told by the PUB, occurs once every 50 years. It could be tomorrow. But we have to plan accordingly. Most importantly, we have to have a proper drainage system... (that is) being continually upgraded, and a proper response system."

The damage in affected areas, such as an underground carpark at Sixth Avenue Centre, is still being calculated. Residents told MediaCorp that workers toiled through most of the night to pump out the flood waters, which apparently came up to about 2 metres.

Workers were still pumping out debris that had swept into the drainage areas on Friday. Some residents said they were still in shock after seeing their cars float away from their lots.

At Eng Neo Avenue, the Zhang residence looks none the worse for wear. But that was after a massive clean-up into the night as flood waters had caused the pond to overflow and damage the wooden floors.

Myrna Morales, a domestic worker, said the flooding was so bad that carpets had to be removed to mop up the water.

Amidst the clean-up, car workshops have reported increased business for repair works that range from drying out cars to repairing engines, costing over S$10,000.- CNA/so

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Bonfires of Trust, Flash-floods of Pain: Bukit Timah Floods 2009
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