Minister for the Environment and Water Resources, Dr Vivian Balakrishnan said it's "not acceptable" for a major expressway to shut down due to flooding.
He was referring to the early morning floods sparked by a torrential downpour on Thursday which hit mostly the western areas of Singapore and forced the temporary closure of the Ayer Rajah Expressway.
"We're going to need to do some work there," he said.
"We will need some time, but I am confident that we can make an improvement to the situation...I told (national water agency) PUB we've got to do our best to make sure this doesn't recur in the future."
He was speaking on the sidelines of an event at the National University of Singapore.
PUB said in a statement that all four lanes of the Expressway were temporarily closed due to overflowing drains and the rising tide. Flood waters reached a depth of half a metre and subsided within 40 minutes.
PUB said it has plans to upgrade the Sungei Pandan Kechil, which serves this section of the AYE.
Heavy rain plus high tide cause flooding
Overflowing Sungei Pandan Kechil canal due for upgrading, says PUB
Daryl Chin Straits Times 6 Sep 13;
YESTERDAY'S floods were the result of the unfortunate coming together of two forces of nature - heavy rain and high tide.
The rain was particularly heavy as a result of "the convergence of winds over the region", according to the National Environment Agency.
It fell heaviest near Kent Ridge, reaching 102.8mm in just over an hour. The nearby Sungei Pandan Kechil canal was supposed to direct the rainfall out to sea, but it was already filling up fast because of the high tide.
The ensuing lack of drainage led to flood waters rising to a height of half a metre across 90m of the Ayer Rajah Expressway (AYE), where all four lanes leading to the city were closed for about 40 minutes.
National water agency PUB's chief engineer of drainage planning, Mr Ridzuan Ismail, said yesterday that the canal was due for an upgrading and that a preliminary study had already been done.
It had overflowed before. In 2011, the flooding led to the basement carpark of Varsity Park Condominium along West Coast Road becoming inundated, leaving cars in bumper-high water.
Then in February this year, intense rain in the area led to the closure of one lane of the AYE.
Yet upgrading of the canal in this problematic area will not happen immediately. Mr Ridzuan said that it will take a further nine months to determine the scope of works needed, including how much the canal's capacity can be expanded and what construction method to use.
At the earliest, work will only begin in the first half of 2015, and it may take a few years depending on the scale of work and site conditions, he added.
Meanwhile, the heavy rain also caused trouble in other parts of Singapore. Water rose to a height of half a metre along 100m of Commonwealth Avenue, closing two lanes of the road.
Maxwell Road, Cuscaden Road, Alexandra Road and Lorong Kismis were hit with flood water reaching a height of up to 0.2m.
PUB data showed that drainage improvement work in these areas is either ongoing or will soon begin - with the exception of Alexandra Road.
The work in Commonwealth Avenue, for instance, will cost $13 million and involves putting in a new 50m-long culvert and enlarging the existing road drain. It will be completed by 2015.
Assistant Professor Vivien Chua from the National University of Singapore's civil and environmental engineering department said these areas could have faced an increased risk of flooding because the surrounding area was built up, leaving a lack of permeable surfaces to absorb the rain.
Another alternative solution, she added, could be to use detention basins. The West Coast Park near the Sungei Pandan Kechil canal, for example, could house a "dry pond" which stores water during heavy rainfall and high tide conditions, but can be drained and used for recreational purposes during drier weather.
Mr Ridzuan said that PUB also has an ongoing drainage improvement programme to alleviate floods in hot spot areas and to increase flood protection. In 2010, PUB identified 22 canals and waterways that needed upgrading.
"However, we cannot possibly design our drainage system to cater to the most extreme of storms, due to limited land space," he noted.
Major drainage works in pipeline: Balakrishnan
Dylan Loh Channel NewsAsia 5 Sep 13;
SINGAPORE: Heavy rain on Thursday morning pelted the island and caused flooding in parts of Singapore.
Flash floods were reported at the junction of Commonwealth Drive and Commonwealth Avenue, Alexandra Road at the junction of Delta Road, Lorong Kismis, the junction of South Bridge Road and Maxwell Road, the junction of Cuscaden Road and Tomlinson Road, and along the Ayer Rajah Expressway towards Clementi.
The National Parks Board reported four cases of fallen trees at Bukit Timah, Outram and Bukit Batok. No injuries were reported.
One fallen tree at Dunearn Road damaged three cars and obstructed three lanes. The obstructions were subsequently cleared.
One of the places worst hit by floods was the Ayer Rajah Expressway which was closed to traffic as drains overflowed due to intense rainfall and rising tide.
Environment and Water Resources Minister Vivian Balakrishnan said on his Facebook page that plans are in place to expand the Sungai Pandan Kechil canal along the expressway and added that these plans have to be expedited.
In the longer term, a barrage may even be built to control water levels.
Dr Balakrishnan said: "We're bringing new technology to bear on getting accurate topographic maps. We can also then use that to model future events under greater climate or weather stress and that will also help us plan, in a more refined way, our future infrastructure that will be necessary to deal with these events.
"We will need some time but I'm confident that we can make an improvement to the situation. I think it's not acceptable to have a major expressway shut down because of a flood."
National water agency PUB said construction work to upgrade a section of the Sungai Pandan Kechil canal will commence in the first half of 2015.
And to increase flood protection for the area, PUB will expand the culvert openings that drain into Sungei Pandan Kechil to improve the flow. The work will be completed by end of this year.
The PUB said in a statement issued on Thursday afternoon that the downpour over the central and western parts of Singapore began at 8.15am and ended around 9.30am.
The heaviest rainfall was recorded at Kent Ridge with a rainfall of 102.8mm from 8.10am to 9.40am. It peaked between 8.15am to 8.50am, with a rainfall of 82.2mm.
At Kent Ridge, a mini-waterfall was spotted as undergraduates reported ankle-deep waters within and around the National University of Singapore (NUS).
At the university’s science faculty bookshop, damage control was underway.
Staff said while this is not the first time a flood has occurred, it was definitely the worst, with an estimated S$20,000 worth of books damaged.
Patricia Foo, assistant manager at NUS' Multi-Purpose Co-operative Society Limited, said: "The water level rose to above the drain level and we tried our best to put in a lot of cardboards to actually stem the water from flowing into the shop but it was too late. The water just came in, rush in and we couldn't even salvage any books."
The shop is looking at investing in sandbags to prevent similar occurrences.
NUS said classes and daily operations on campus were not affected by the flash floods.
The university has enhanced the drainage system to mitigate flooding due to heavy downpours and will continue to look for solutions to reduce the incidence of flash flooding.
Over at Fairfield Methodist School in Dover, students had to clamber around fences to avoid wet ground.
The National Environment Agency said a convergence of winds over the region led to heavy rainfall on Thursday.
It added that for the next few days, thundery showers are expected mainly in the morning and early afternoon.
- CNA/fa
Flash floods shut down part of AYE for 40 mins
Western Singapore hit by floods, expect wet days in next two weeks
Rachel Au-Yong Straits Times 6 Sep 13;
FLASH floods hit many parts of western Singapore yesterday morning, shutting down a city- bound stretch of the Ayer Rajah Expressway (AYE) for 40 minutes during morning rush hour.
Cars were stranded along the expressway, after water from the heavy rain, which could not find its way into the bloated Sungei Pandan Kechil canal, spilt onto the 90m stretch, creating a 0.5m deep pool.
It is not the first time that the canal has overflowed onto the expressway, although yesterday's episode was the worst.
Minister for the Environment and Water Resources Vivian Balakrishnan said PUB, the national water agency, will have a lot to do in that area now. "I think it's not acceptable to have a major expressway shut down because of a flood, so I told PUB we've got to do our best to make sure this doesn't recur in the future."
The most immediate task, he said, is to expand the culverts immediately to the south of the AYE. For the long term, PUB will look at expanding the canal. A barrage may even be necessary, added Dr Balakrishnan.
The National Environment Agency (NEA) said 119.2mm of rain was dumped before noon yesterday. That is more than the amount of rain that fell for the whole of last September - 107.6mm.
At least five trees were uprooted by the torrential downpour, including one during evening peak hour on Orchard Road which blocked four of its five lanes.
Two cars were hit by the tree outside Singapore Visitors Centre, with a pregnant woman who complained of giddiness taken by ambulance to the hospital.
Earlier, the Bukit Timah area also faced pile-ups after two trees fell on cars in Dunearn Road and Sixth Avenue. A Jaguar bore the brunt of a large fallen tree at Dunearn Road, with its exterior crushed and its seats exposed.
The driver, a retiree who wanted to be known only as Mr Seah, told The Straits Times: "I was on my way home when I heard a loud bang. Thank goodness I did not get a heart attack."
PUB said the heaviest rainfall was recorded at Kent Ridge, where several facilities in National University of Singapore were submerged in knee-high water.
Third-year life sciences student Uthara Nair said: "It was like the making of Atlantis - benches and chairs were completely covered, and water was coming down the stairs."
Commonwealth Drive was also badly hit, with major congestion after the Sungei Ulu Pandan canal overflowed as well. At least two lorries and a car broke down at the junction of Commonwealth Avenue and Commonwealth Drive, with water levels reaching the car's steering wheel.
Expect more rain than average in the next two weeks. NEA says south-west monsoon conditions will mean the likelihood of short thundery showers in the late morning and early afternoon, and widespread showers with gusty winds in the pre-dawn hours on one to two days.
PUB advises the public to exercise caution as flash floods may occur when there are heavy storms. Information is available from its 24-hour call centre on 1800-284-6600 or its Facebook page.
Additional reporting by David Ee and Royston Sim
Floods hit western Singapore
Xue Jianyue Today Online 6 Sep 13;
SINGAPORE — Flash floods, uprooted trees and massive traffic jams were reported in many areas yesterday morning after a thunderstorm lasting over an hour dumped copious amounts of rain over the central and western parts of the island. The flash floods led to the unprecedented closure of a stretch of a major highway, the Ayer Rajah Expressway (AYE).
Meanwhile, parts of the Kent Ridge MRT Station, commuters said, resembled a stormwater drain, as water cascaded down escalators and walls. Several motorists reported that their cars had been inundated with water, and uprooted trees made it a miserable morning for other drivers. One fallen tree at Dunearn Road damaged three cars and obstructed three lanes, according to the National Parks Board.
The intense thunderstorm was behind at least four reported cases of fallen trees at Bukit Timah, Outram and Bukit Batok, but no injuries were reported.
At the National University of Singapore (NUS), students and staff had to wade through knee-high waters in some areas, as the heavy rain caused flooding at the science and engineering faculties.
Yesterday’s flooding was the most widespread since 2010, when parts of Orchard Road were inundated, rendering the busy Scotts Road junction all but impassable to traffic, the closure of several businesses and millions of dollars worth of losses. That episode led to a raft of measures to control flooding in several vulnerable areas, some of which are in progress till this day.
At the AYE, the drains overflowed due to the intense rainfall and rising tide, said the national water agency PUB. “Flood waters reached a depth of half a metre and subsided within 40 minutes,” it added.
This was the second time a stretch of the AYE, which spans 26.5km between Telok Blangah and Tuas, was inundated. On Feb 8, a stretch near the 9.6km mark had experienced a flash flood due to intense rain. One lane was affected then but the expressway was passable to traffic, said the PUB. This prompted the authority to draw up plans to upgrade drainage capacity at this stretch.
Still, the closure of a stretch of a major expressway due to flash floods was unacceptable, said Environment and Water Resources Minister Vivian Balakrishnan.
Speaking on the sidelines of an event at the NUS, he said: “I think it is not acceptable to have a major expressway shut down because of a flood. I have told PUB that we’ve got to do our best to make sure that this doesn’t recur in the future.”
Posting on his Facebook page earlier, he said the expansion of the Sungai Pandan Kechil — one of two canals that overflowed — would be expedited.
The PUB said heavy rain fell over the central and western parts of Singapore yesterday morning from 8.15am to 9.30am. The heaviest rainfall was recorded at Kent Ridge, with 102.8mm from 8.10am to 9.40am. It peaked between 8.15am and 8.50am, with a rainfall of 82.2mm. By noon, 119.2mm of rain fell at Old Toh Tuck Road — more than half of the average monthly rainfall of 168.7mm for the month of September. The National Environment Agency put yesterday’s thunderstorm down to “the convergence of winds over the region”.
At Boon Lay Way, traffic was forced to a near standstill, according to commuter Shin Tan, 24. “The bus 188 took 40 minutes to move one stop,” said the NUS undergraduate. He subsequently disembarked at the next stop, taking another bus in the opposite direction towards Jurong East MRT for an alternate route to school.
Flash floods at Commonwealth Avenue also forced smaller vehicles to take alternative routes. One vehicle attempted to plough through flood waters but got stranded on that road, according to TODAY reader Mohamad Hadir, who snapped a picture of the inundated road. Buses and other large vehicles, however, managed to drive through the flooded road and pick up commuters at the bus stop, he added.
At Kent Ridge MRT Station, the underpass linking the station to a nearby bus stop was also flooded. “I was shocked when I saw the scene,” said NUS Alumnus Ho Kinh Dat, 24, whose photo of stormwater cascading down walls went viral in cyberspace.
“People were hiding under the shelters and few dared to walk past the ‘waterfall’. Some took off their shoes to walk through the water.”
For the next few days, thundery showers are expected mainly in the morning and early afternoon.
Flash floods hit several areas in western Singapore
David Ngiau Today Online 5 Sep 13;
SINGAPORE — Heavy rain triggered flash floods in many areas in the west this morning (Sept 4), closing a section of the Ayer Rajah Expressway (AYE). The floods had subsided by 9.48am, according to the PUB.
Motorists travelling towards town on the AYE encountered massive congestion before Clementi, with electronic road signs announcing that the three-lane expressway was closed after the Clementi exit. The PUB said that drains overflowed at the AYE due to the intense rainfall and rising tide, with flood waters reaching a depth of half a metre, and subsided within 40 minutes.
Flash floods in Singapore, Sept 5 2013
Flash floods in Singapore, Sept 5 2013
All four lanes of AYE towards ECP were closed to traffic during the flood.
The PUB said in a statement issued in the afternoon that the downpour over the central and western parts of Singapore began at 8.15am and ended around 9.30am.
The heaviest rainfall was recorded at Kent Ridge with a rainfall of 102.8mm from 8.10am to 9.40am. It peaked between 8.15am to 8.50am, with a rainfall of 82.2mm.
TODAY readers sent in pictures of a flooded Kent Ridge MRT station and reported waters at the National University of Singapore campus reaching knee-deep levels at the science faculty blocks on Lower Kent Ridge Road, near the National University Hospital (NUH). Other reports said that waters were only ankle deep at the engineering faculty near Clementi Road, on slighly higher ground.
On Dunearn Road, a tree fell on two cars, blocking traffic to all vehicles except for motorcycles.
Some of the worst floods were reported in the Commonwealth area, with reader Mohamad Hadir sending us a photograph of the interior of a car flooded up to near the steering wheel.
In its statement, the PUB said that flash floods were reported on the AYE at the 9.6km mark, towards the East Coast Parkway (ECP); on Commonwealth Avenue, Commonwealth Lane and Commonwealth Drive; the junction of South Bridge Road and Maxwell Road in Chinatown; the junction of Cuscaden Road and Tomlinson Road near Tanglin Mall; on Alexandra Road towards Lower Delta Road (near Ganges Avenue); and Lorong Kismis near Jalan Jurong Kechil.
The PUB said it has plans to upgrade Sungei Pandan Kechil, which serves this section of the AYE near the NUS High School. Sungei Pandan Kechil connects to Pandan Reservoir.
For Commonwealth Avenue, the PUB has scheduled drainage improvement works, which will commence in the fourth quarter of this year and are expected to be completed by first half of 2015.
The PUB added that it advises the public to exercise caution as flash floods may occur in the event of heavy storms.
Drainage network has to be ‘future-proofed’
Sumita d/o Sreedharan Today Online 6 Sep 13;
SINGAPORE — Minister for the Environment and Water Resources Vivian Balakrishnan said the drainage network will have to be “future-proofed” to cope with intense thunderstorms that may hit the island, similar to the one that caused yesterday morning’s flash floods in several parts of Singapore.
Speaking on the sidelines of an event at the National University of Singapore (NUS), Dr Balakrishnan laid out immediate and long-term plans for the two rivers, Sungei Pandan Kechil and Sungei Ulu Pandan, which overflowed as a huge amount of rainwater fell yesterday morning.
The walls near the opening of the culvert below the Ayer Rajah Expressway, near NUS, will be widened to improve water flow. Work will start this month and be completed by the end of the year. The Sungei Pandan Kechil canal would be extended to make sure it has sufficient capacity to deal with the increased run-off.
Construction work will commence in first half of 2015, said national water agency PUB. Beyond these moves, the authorities are also examining if a barrage is necessary in the future to deal with the tidal influence.
As for Sungei Ulu Pandan, the area around Commonweath Avenue is undergoing drainage improvement works but the culvert underneath Clementi Road will have to be examined in the long term. These works are “a major operation” as the drainage system is inter-connected, said Dr Balakrishnan.
Engineering experts TODAY spoke to said even though more can be done to ensure that significant flooding does not happen again, it will be unrealistic to eliminate it forever.
Engineer Chong Kee Sen, who is the Vice-President of The Institution of Engineers in Singapore, said the works will “take time”. “We must be realistic, the whole problem cannot be eliminated and we can never say there will never be a temporary build-up of water at all. But the authorities will have to look into areas of serious flooding and they will have to relook what other measures can be done, those with significant flooding have to be re-looked at as flooding on major infrastructure can cause significant inconvenience,” he added.
Dr Chiew Yee Meng, who is Head of Environmental and Water Resources Engineering at Nanyang Technological University, noted that the scale of the area affected yesterday was “quite extensive”, spanning from the Tanglin area to Chinatown and to the southwest of the island.
“The authority is trying its best to overcome the problem, but the flow of flood water has to be tackled holistically because fluid is a continuum and cannot be solved individually as interfering in one area may bring about unexpected effects both upstream or downstream of the initial problem area,” said Dr Chiew, who is a Professor in Civil and Environmental Engineering.
He called for greater studies to be conducted. “While the authority has carried out certain large drainage works in the country in the past, how this affects the overall drainage pattern in the whole country should be carefully studied.
“This will allow one to come up with a holistic mitigation approach. The issue of climate change, or changes to rainfall intensity, is another topic that remains unresolved presently,” said Dr Chiew.