Did a multi-million dollar project to raise low-lying roads in the Orchard area last year contribute to Sunday's flash floods? Or did it prevent even further damage?
This after two Orchard Road buildings -- Tanglin Mall and St Regis Residences -- were hardest hit by Sunday's floods -- the worst this year.
The Orchard Road Business Association (ORBA), for one, has questioned if the Public Utilities Board project has actually made the problem worse.
ORBA executive director Steven Goh said "It's kind of like an anniversary for us. It happened last year on June 16... and the PUB road raising works has almost been completed."
"It seems like... the problem (had) been transferred from the downstream of Orchard Road to the upstream of Orchard Road," he added.
But the PUB has rebutted Mr Goh's claim and said the flooding would have been worse without the project, it told MediaCorp.
PUB announced last year a $26 million project to raise a 1.4km stretch from Orange Grove Road to Cairnhill Road by an average of 300mm. The project, which started last November, is due to be completed by the end of the month. Currently, the junction of Cuscaden Road and Tomlinson Road is being raised.
At the time, PUB had said that when works are completed, it would "prevent rainwater from overflowing onto the roads but instead contain it inside the canal to be conveyed towards Marina Reservoir. It will also help prevent future flash floods."
However, the PUB did admit that a software glitch led to Tanglin Mall and St Regis Residences not being alerted of Sunday's impending flash floods.
It said all other buildings in the area, such as Delfi, Lucky Plaza and Tong Building received the flood alerts. PUB said it would rectify the problem immediately.
Tanglin Mall was among the hardest hit mall on Sunday with several shops having to close temporarily after flood water from Level One, which was at road level, started pouring in.
Within minutes, water fell like a mini-waterfall onto Basement One. Several businesses -- a supermarket, food court and various shops -- were submerged in ankle-deep water and had to close. There was also widespread chaos after the basement carparks were also affected.
In June 2010, similar floods along Orchard Road cost businesses hundreds of thousands of dollars.
But this time, employees said the floods were worse.
The Little Gym instructor PJ Lucero said on CNA, "The last time it happened, it was actually more mild. We were still able to open the facility for the day. Today (Sunday), of course, everything got submerged, that's why we had to close down.
"In fact, after the first time it happened, we had sandbags ready. We did use those sandbags today (but) it didn't work. The water just went through it".
Chen Jiahui, store manager of Spinelli Coffee Company along Forum Shopping Mall, added, "This is the second time (it flooded). It's really bad, so I hope that the management are doing something about it".
National water agency PUB said the severity of the flood at Tanglin Mall was something it had not seen in the last 25 years.
It said rainfall was more intense than that of June last year, when various parts of Orchard Road were flooded. About 65mm of rainfall was recorded within 30 mins on Sunday morning, compared to 100mm within two hours on June 16, 2010.
Later in the day, at a press conference which was also attended by Minister for the Environment and Water Resources, Vivian Balakrishnan, PUB explained that the flash floods on Sunday morning were caused by two bouts of heavy rainfall.
It said the first bout of rainfall started slightly past 6am, and second downpour, which was more intense, occurred at about 10.30am.
Speaking after inspecting the flood areas at Tanglin Mall, Dr Balakrishnan said, "Personally, I think our weather has changed. I'm actually psychologically prepared for it to get worse."
"You're dealing with nature, and you're dealing with the weather; you have to be prepared that there is a limit to human engineering and what we can deliver, " he added.
"But having said that, let us make sure we have done the best we can and within those limits, then cope with whatever else that nature throws at us."
In a Sunday post on his blog entitled "Focus of floods: 5 Key questions", the Minister also wrote "We are dealing with Nature, and Man needs to be humble when addressing the challenges that Nature poses".
He also admitted that "sometimes despite our best efforts, we cannot win" when dealing with flood issues but he promised that "we will be open and transparent. We will share as much data in real time as possible so that solutions and precautions can be devised for the immediate and long term."
PUB chief executive Khoo Teng Chye, meanwhile, said he is studying some possible solutions to prevent future occurrences.
"These include, possibly, building a big retention pond near where we can then trap some of the peak flows," Mr Khoo said.
"The other alternative is to really create a diversion canal from where this pond is to the Singapore River. But given Singapore's built-up situation, these are very, very expensive schemes."
The heavy downpour early on Sunday also triggered flash floods across several parts of the island.
Senett Estate, Potong Pasir, MacPherson, Toa Payoh and Bukit Timah were also partially submerged by floods.
Two lanes along Bukit Timah Road near Cuscaden and Hillcrest Road were completely impassable to traffic at one stage. So too was the Kranji Expressway (KJE) at the slip road towards Woodlands.Micro-blogging platform Twitter also lit up with hundreds of tweets, shortly after the flash floods (#sgfloods) hit.
Ex-model and VJ Nadya Hutagalung (@Nadya_HutaGalng) tweeted, "Eng Neo avenue flooded!"
Another Twitter user Akmal Hadi (@Athrun988) tweeted, "Singapore is gonna be another Venice at the year end monsoon season if the government's not gonna do anything about it soon."
Another user, Jacqui T (@jacquilah) tweeted, "First world nation with third world drainage system. Wonderful."
Charlotte Ong (@onglette) also posted a series of pictures of Tanglin Mall flooding and tweeted, "Check out the waterfall in the shopping centre" and "First level flood pouring down to basement."