Ms Lim had asked the minister to clarify what she termed as 'confusing statements' in the media about the role of the barrage in the floods, pointing out that PUB's Chief Executive Officer Khoo Teng Chye had earlier said it was not to be blamed for the June 16 flooding along Orchard Road. When opened to great fanfare two years ago, the $226 million Marina Barrage was being touted as the solution to relieve flash floods in low-lying areas around the city. Explaining the role of the barrage, Dr Yaacob said it played three main roles, that of a freshwater reservoir, to prevent floods as well as for recreational activities. During a rain storm, seven pumps and nine crest gates at the barrage are used interchangeably to release water out to sea depending on the prevailing tidal levels and predictions based on statistical modelling.[Link]
Dr. Yaacoob basically stuck to the explanation that the 16 June 2010 Orchard Rd flood was caused by 2 bursts of heavy downpour 30 minutes apart- 100mm of rainfall within 2 hours and clogged drains were the causes. This explanation is not satisfactory because Orchard Road area had 2 floods after 16 June after PUB said it will monitor drains for debris and rainfall was not as intense. The govt will look at look at widening Stamford canal to prevent future floods....this again is already behind the curve because there were many other places that were flooded 2 days ago Upper Thomson, Bukit Timah, Stevens Rd, Orchard Road, Cresent Road, Bedok and Sims Ave[Link]....a lot more has to be down all over Singapore.
UPDATE : I did a quick check on the Internet and found that the construction of barrages around the world to prevent or control flooding very often leads to increased flooding as an unintended consequence[Check for yourself here]. The reason is water flow (fluid dynamics) is highly complex and is often not amendable to analysis. One hint that something has gone wrong is areas that don't normally flood starts flooding (think Orchard Road). When the big flood in Orchard Road first occurred, the PUB quickly put out a statement that it was caused by debris and would be worse if the Marina Barrage was not there. Now that we have 3(?) other floods since then and floods recurring at Orchard Road at much lower rainfall than the earlier one, I think it is time for them to check all the possibilities not just the ones that absolve the govt from blame and conveniently lead to conclusions that nothing needs to be done.
"The Marina Barrage is the result of Minister Mentor Lee Kuan Yew’s vision nearly two decades ago when he envisaged damming the mouth of the Marina Channel to create a freshwater reservoir" - PUB Website
A popular hypothesis has emerged among Singaporeans that the Marina Barage is a possible cause of the floods. I'm not an expert in floods so I cannot say with any certainty if this hypothesis is true. Remember a few weeks ago when Orchard Road became flooded, the govt quickly came out with an explanation that it was due to a clogged drain and that PUB will be monitoring the drains closely[Link]. How then do they account for the floods that came after that one? Orchard Road has been flooded a few times since then. The govt' has lost credibility due the flood issue and they will lose more if they don't come up with a good explanation and long term solution soon. Be it climate change, drainage or the Marina Barage, Singaporeans need to know what is going on and that there is a plan and solution in place that will prevent these damaging floods. Singaporeans are not so reasonable to expect 100 new drains to be constructed by tomorrow but they have to start working on the solution ASAP....how else can the govt answer to those whose goods, cars and homes have been damaged in recent weeks.
Why do so many Singaporeans think the Marina Barrage is the culprit?
The Marina Barrage (Chinese:滨海堤坝) is a dam in Singapore built across the mouth of the bay, between Marina East and Marina South. It was officially opened on 1 November 2008. [Wikipedia]
Here is an air picture of the barrage:
When the Marina Barrage was opened, it was said that it can be used for "flood control". The barrage has steel gates that separate the sea water from the fresh water. The barrage can prevent rising sea tide from flooding the island - but the problem is water flow in the other direction from the island to the sea. During heavy rainfall, the steel gates are opened to allow the storm water to flow into the sea. According to the hypothesis, herein lies the problem, in the past without the barrage, storm water flows freely into the ocean but with the barrage, this flow of water is impeded by the structure causing a back pressure leading to rising water levels on the island.
Netizens and ordinary Singaporeans do not have the data or expertise to rigorously prove this hypothesis. Only the govt and its experts can come up with rigorous explanations. I highlighted this popular hypothesis only to show the need for the govt to step forward and explain what is going on. The public generally don't accept "once in 50 years" and "debris in the drain" type of convenient (convenient for the govt to do nothing) explanations which now look rather ridicious given the frequency of these floods.
Some other flooding incidents associated with building of barrages in other countries:
In Kuching : http://anilnetto.com/development-issues/floods-in-kuching/
The Malaysian govt denied it because it was the one that build the barrage.
An official report by the Dutch Government found the construction of a storm surge barrier across the Oosterschelde estuary in the 1980s actually increased the risk of flooding in the area. [Link].