Options narrow for Stamford Canal

Esther Ng Today Online 10 Jan 12;

SINGAPORE - Ponds to hold rainwater could be built upstream of Stamford Canal - blamed for the Orchard Road floods - to alleviate future floods in the area.

Revealing this option in Parliament yesterday, Minister for the Environment and Water Resources Vivian Balakrishnan also rejected suggestions to deepen the canal given its existing depth. Another option is to build a diversion canal from the upper third of the Stamford Canal drainage area to the Singapore River, he added.

But even as the PUB is studying options to raise the capacity of the Stamford Canal - which needs to increase by 30 per cent to reduce the risk of flooding - there are constraints, said Dr Balakrishnan.

For one, the detention ponds - which are about the size of 40 to 50 Olympic-size pools - will not come cheap. "Putting aside land in precious real estate, in the Orchard Road area, is something which we don't enter lightly," said Dr Balakrishnan.

Alternatively, building a diversion canal will cost between S$300 million and S$400 million. "To now embark on further surgery on Stamford Canal will cause enormous disruption to the services and operations, to the pedestrian and vehicular flow along Orchard Road," said Dr Balakrishnan.

"We're constrained on the ground and there will also be major financial and fiscal factors that we have to take into account."

Asked by Jurong GRC MP Ang Wei Neng why the canal could not be deepened, Dr Balakrishnan pointed out that it was already very deep, and it is not the objective to create a "Stamford basin".

"We need to either slow down the rate of inflow into Stamford Canal through detention ponds or have an alternative bypass," he reiterated.

Could the loss of open spaces from large-scale development have contributed to flooding, and will the ministry require developers to submit environment impact studies prior to construction, asked Hougang MP Yaw Shin Leong.

Dr Balakrishnan replied that the expert panel - which was assembled after the flash floods - will publish its findings this week on whether urban build-up had contributed to the problem.

He acknowleged that "greater collaboration" among planning authorities was essential to make future developments "sensitive and rational" in coping with the changing climate.

One finding from the Metereological Service Singapore is that rainfall has become more intense over the past 30 years. As such, Singapore now sees a lot more flash floods - "transient localised episodes" of about 30 minutes - instead of prolonged flooding.

Referring to the latest incident on Dec 23, Dr Balakrishnan pointed out that Orchard Road remained "passable" to traffic due to the completion of road-raising work in June.

"Extensive measures" taken by building owners also meant that flooding was "confined" to the basements of Liat Towers and Lucky Plaza, he noted.

As for claims that the Marina Barrage had contributed to the flooding, Dr Balakrishnan pointed out that the water level of the barrage did not affect the "hydraulic situation" of water in the upper reaches of Orchard Road as the "platform level" of Grange Road was eight metres above mean sea level.

The barrage also helps "protect" low-lying areas such as Chinatown, he added.

Not feasible to expand canal under Orchard Road: Minister
It has reached full drainage capacity, says Balakrishnan
Feng Zengkun Straits Times 10 Jan 12;

SINGAPORE does not intend to be like Venice, with canals everywhere, said Minister for the Environment and Water Resources Vivian Balakrishnan in Parliament yesterday.

'So there has to be a reasonable limit to how much we prepare for the future,' he said, referring to the floods that have occurred in Singapore over the past two years.

He was responding to MP Ang Wei Neng's question on why the Stamford Canal cannot be deepened.

While he acknowledged the Stamford Canal's capacity needs to be increased by 30 per cent in the long run, widening and deepening it will not be feasible.

'In the case of Stamford Canal, which lies under Orchard Road, we have run out of drainage capacity,' he said, explaining that there is always a drainage reserve factored into all drains.

Any works to the 4km-long canal will cause massive disruption to traffic and businesses along Orchard Road, he said.

Part of the canal was full when prolonged and intense rain fell on Orchard Road on Dec 23 last year, causing flooding in Liat Towers and Lucky Plaza.

The canal also could not cope during a downpour in June 2010, dramatically causing the junction of Scotts Road and Orchard Road and two malls to be submerged, ringing up an estimated $8 million in damage.

Dr Balakrishnan attributed these two incidents, and another in June last year that caused flooding in the Tanglin area, to more intense rain and increasing urbanisation.

After the 2010 flood, national water agency PUB raised a 1.4km stretch of Orchard Road between Orange Grove Road and Cairnhill Road, which it said prevented the road from being flooded during subsequent heavy rains.

It has also stepped up checks on canals and drains during the current north-east monsoon season, to make sure they are not blocked.

Last month, it revised the drainage codes for new buildings and buildings to be redeveloped, so they must have higher platform levels and drainage capacities.

The Stamford Canal, which serves the Orchard area, starts at the Botanic Gardens and Dempsey Hill, passes through the Bras Basah area and the city centre, and flows into the Marina Reservoir.

He said while there has been much speculation over the role of the Marina Barrage, it has helped to maintain the water level in the Marina Reservoir below the mean sea level. If not for the barrage, seawater would raise the water level in the reservoir, which could lead to flooding in nearby low-lying areas such as Chinatown.

Given the constraints of the Stamford Canal, the Environment Ministry is studying alternative methods to prevent flooding in the area; the study will conclude in May.

He gave details on some of the ideas, including a water retention pond to hold rainwater and a diversion canal to bring floodwater into the Singapore River. Both options would be very costly, he said.

For the retention pond, he said: 'We would need land two to three times the size of a football field. Putting aside land like that in precious real estate in the Orchard Road area is something we should not enter into lightly.'

The pond should have a capacity of 40 to 50 Olympic-sized pools, and is meant to retain water upstream.

He added a diversion canal would cost between $300 million and $400 million.

'In the long run, these need to be done,' he said.

In the short term, more measures can be implemented to prevent the floods or reduce their impact, he added.

The ministry is investing more into infrastructure such as sensors, closed-circuit television monitors and data collectors to better predict the storms and keep tabs on possible floods, he said.

Assistant Professor Vivien Chua of the National University of Singapore's Department of Civil and Environmental Engineering suggested ways the ministry could speed up water flow within the canal, which was mooted by Dr Balakrishnan.

'Friction to fluid flow can be reduced by smoothening the canal banks and bed... and removing coarse sand and gravel on the bed,' she said, adding that this would help transport water away from the flood-prone areas more quickly.

PUB should not have used the word "ponding": Balakrishnan
Hetty Musfirah Channel NewsAsia 9 Jan 12;

SINGAPORE: The capacity of Stamford Canal will be increased by at least a third to reduce the risk of flooding along Singapore's shopping belt of Orchard Road.

Environment Minister Vivian Balakrishnan said in Parliament on Monday, that a consultancy study is underway and is expected to be completed by May.

He said such projects can be costly, but his ministry is prepared to undertake longer term investments.

But he cautioned that Singapore faces constraints.

Dr Balakrishnan said said: "I think many members will be familiar that whenever PUB has a drain, we have a drainage reserve.

"In other words, we always have space where if we need to deepen or widen a drain, we will take land from the owners or public utilities.

"Well in the case of Stamford Canal, which lies under Orchard Road, we've run out of drainage capacity. Secondly, to now embark on further surgery on Stamford Canal, would cost enormous disruption to services and the operations, pedestrian flow and vehicular flow along Orchard Road. I put all this because I want you all to understand that we are constrained."

The Stamford Canal starts upstream at the Botanic Gardens and Dempsey Hill, passes through Bras Basah and City Hall areas, before draining into the Marina Reservoir.

The area of special concern is a basin between Cuscaden and Cairnhill Roads at Orchard Road.

There have been three episodes of flooding in this area over the past eighteen months.

Dr Balakrishnan said the episodes are part of a larger pattern of rainfall change in Singapore over the past decades.

On 16 June 2010, some 100mm of rain fell in the area over two hours, causing Orchard Road between Cuscaden and Cairnhill Roads to flood to a depth of 300mm.

On 5 June 2011, some 124mm of rain fell over about four hours, and caused the Tanglin area to be flooded to a depth of 100mm.

Compared to the incidents on 16 June 2010 and 5 June 2011, the latest incident on 23 December 2011, saw the heaviest rainfall of 153 mm recorded over three hours.

Dr Balakrishnan noted that Orchard Road remained passable to traffic due to the completion of road raising works in June 2011.

But he noted that any form of flooding needs to be addressed.

Dr Balakrishnan said: "The technical difference between a flood, a flash flood and a pond - let me just say that as far as I'm concerned.

"PUB should not have used the word, "ponding".

"As far as I'm concerned, I call a spade a spade, a flood is a flood.

"As long as there is water accumulating somewhere, where it is not supposed to be, as long as it has implications on human safety, on business operations, that is a flood, that is a problem that needs to be resolved, PUB and the building owners must resolve it."

Dr Balakrishnan said PUB is evaluating various options.

This include storm water detention ponds in the upstream section, or a new canal to divert storm water from upstream portions of the catchment to the Singapore River.

Dr Balakrishnan said: "These detention ponds are not going to be cheap, to give you an idea of scale, they have a capacity of 40 to 50 Olympic sized pools.

"We will need land two to three times of a football pitch, putting aside land like that in a precious real estate in the Orchard Road area, I think members will agree, (it) is something we don't enter into likely.

"I set this very simple challenge to PUB. Let's us assume that we will continue to have storms, exactly similar to what we have in the last three episodes. In fact, let us assume further.

"Let us assume that it may be even worse than that. The reply that the engineers came back to me is, is that "if we want to able to be almost guaranteed that we can cope with similar storms of the last eighteen months, then in the long run we need to increase the capacity of Stamford Canal by 30 per cent."

Dr Balakrishnan said flood protection measures undertaken by building owners in Orchard Road over the past 18 months were generally effective, except for the basements of Liat Towers and Lucky Plaza that were overwhelmed by the heavy downpour on 23 December.

PUB is already working closely with the building owners at Liat Towers and Lucky Plaza to fine tune their flood protection measures, and review operating procedures.

Minister Vivian Balakrishnan has met the building owners of Liat Towers and Lucky Plaza, and is reassured that they will do their best to collaborate with PUB in resolving localised flooding problems."

Dr Balakrishnan said the panel of experts appointed middle of last year to review the overall drainage design and flood protection measures, is expected to complete its work by this week.

Their findings and recommendations will be shared with the public.

- CNA/ck

Expanding Stamford Canal among flood prevention options
PUB may also build canal to S'pore River or keep storm water in upstream section
Chuang Peck Ming Business Times 10 Jan 12;

(SINGAPORE) Stamford Canal will have to be expanded by at least a third to reduce the risk of flooding along Orchard Road.

'PUB is evaluating various options to increase the overall capacity of Stamford Canal,' Environment and Water Resources Minister Vivian Balakrishnan told Parliament yesterday.

A study, due to be completed in May, will consider the option of keeping storm water in the upstream section, or building a new canal to divert storm water from upstream portions of the catchment to the Singapore River.

While there is an urgency to enhance the drainage, Dr Balakrishnan said that the options are very costly - between $300-400 million - and are technically complex in an intensely developed area.

Stamford Canal drains a catchment area of 631 hectares, which starts upstream at the Botanic Gardens and Dempsey Hill and extends downstream through Bras Basah and the city centre.

The stretch that is of particular concern is the basin between Cuscaden and Cairnhill Roads, which include Singapore's shopping belt Orchard Road, where there have been three episodes of flooding over the past 18 months.

The most recent, on Dec 23 last year, saw some 153 millimetres of rainfall recorded over three hours. If the stretch along Orchard Road was not raised, the flood would not have been confined just to Liat Towers and Lucky Plaza which are in the vicinity, said Dr Balakrishnan, who was replying to queries about the recent flood by Members of Parliament Ang Wei Neng (Jurong GRC) and Yaw Shin Leong (Hougang).

Orchard Road itself would 'almost certainly' have faced flooding, affecting traffic flow, the minister said, adding that it was spared and remained passable to traffic despite the even heavier downpour on Dec 23.

'The completion of road raising works in June 2011 provided additional flood protection by preventing storm water from overflowing onto the road,' he said.

The flood protection measures undertaken by building owners on Orchard Road over the past 18 months were generally effective - except for the basements of Liat Towers and Lucky Plaza, which are old buildings, said Dr Balakrishnan.

On the technical difference between a flash flood and a pond, he said: 'PUB should not have used the word 'ponding'. As far as I am concerned, I call a spade a spade. A flood is a flood.'

Dr Balakrishnan added: 'As long as there is water accumulating somewhere where it is not supposed to be, as long as it has implications on human safety or business operations, that is a flood, and that is a problem that needs to be resolved. PUB and the building owners must resolve it.'

A spokesman from his ministry said that the minister has met the owners of Liat Towers and Lucky Plaza, and is reassured they will do their best to collaborate with PUB in fixing the localised flooding problems.

Liat Tower is building a 60 centimetre-high wall to stop rainwater from overflowing from its internal drain into the basement, while Lucky Plaza will be installing flood barriers to prevent water from the pavement flowing into the basement.

PUB is also working closely with the owners of the buildings to fine-tune their flood protection measures and review operating procedures.

Addressing speculation about the role of the Marina Barrage in floods, Dr Balakrishnan said that gates and pumps at Marina Reservoir removed tidal influence from the various drains feeding into the reservoir, helping to keep low-lying areas in the city such as Chinatown free from floods.

But the Marina Barrage has no effect on the upper reaches of Orchard Road, he said.

After investing over $2 billion in drainage infrastructure in the past three decades, low-lying, flood-prone areas in Singapore have been reduced from 3,200 hectares in the 1970s to about 49 hectares today.

But Dr Balakrishnan said that increasing rainfall intensity and rising urbanisation pose an ongoing challenge for Singapore's drainage infrastructure.

Basement shops come up with flood solutions
Straits Times 10 Jan 12;

BESIEGED shop owners in the basements of Lucky Plaza and Liat Towers have come up with solutions of their own after the flood last month, the third in two years.

At Liat Towers, the building management has invested in a $17,000, 60cm-high wall to keep flood water from turning its basement into a pond again. It has also hired a consultant to assess whether its pumps are sufficient.

The management had previously spent $220,000 on pop-up floodgates, and $11,000 on small flood barriers in front of fast-food outlet Wendy's, coffee outlet Starbucks and clothing retailer Massimo Dutti to block flood water.

Mr Chik Hai Lam, the building's supervisor, said: 'We don't expect the Government to pay for any of this, but after the consultant comes, if we upgrade the pump system, we'll have done everything we can.'

Over at Lucky Plaza, the shop owners in the basement, who have also been thrice unlucky, have improvised their own flood barriers.

Heaps of sandbags sit beside drains, ready to soak up water and blockade the entrances if the drains overflow.

Mr Elton Chow, 54, whose Stitchwell Clothiers is near the basement entrance, keeps an eye on the drains. 'If it fills up, we start shouting and alert everyone on the floor,' he said.

Many shopkeepers have installed cabinets at least a good 10cm off the floor to protect their goods.

Mr Lee Siew Kau, 63, who owns shoe shop Relantino Leathers, has fashioned a makeshift threshold from a piece of metal and two rubber wedges. He said: 'If I see the water coming, it takes me 10 seconds to put it at the door.'

The building management is considering installing more pumps to get water out onto the main road, said Mr Chow.

'Right now, we share three vacuum pumps among the shops, so if the water gets in, it's difficult to clean up,' he said.

The management has also obtained in-principle approval from the relevant government agencies to put up flood barriers.

Yesterday, Environment and Water Resources Minister Vivian Balakrishnan said in Parliament that the floods in the Orchard Road area were part of changing rainfall patterns.

'What we are confronted by today are transient, localised episodes typically lasting up to about half an hour or so, and these occur in areas where rainfall intensity has temporarily overwhelmed the local drainage systems.'

He added that Liat Towers and Lucky Plaza are buildings that are more than 30 years old, 'and their basements really make them vulnerable'.

FENG ZENGKUN