Marina Barrage has helped alleviate flooding in many low-lying areas

Amresh Gunasingham Straits Times 20 Jul 10;

THE Marina Barrage helped to prevent flooding in many low-lying areas around the city during the recent floods and has done so since it was opened in 2008, Minister for the Environment and Water Resources Yaacob Ibrahim said in Parliament yesterday.

However, areas farther away such as Orchard Road could still be vulnerable.

Responding to Non-Constituency Member of Parliament (NCMP) Sylvia Lim's question on the role of the barrage in the recent floods, he explained that because the barrage receives water from a large 10,000ha network of canals and drains, areas in central Singapore or farther north could still be flooded if the drains there did not have the capacity to contain water during an intense downpour.

This was the case on June 16, when Orchard Road flooded.

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 chief executive officer Khoo Teng Chye had earlier said it was not to be blamed for the Orchard Road flooding.

When opened to great fanfare two years ago, the $226 million Marina Barrage was 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 - one, as a freshwater reservoir, two, to prevent floods, and three, as a place for recreational activities.

During a rain storm, seven pumps and nine crest gates at the barrage are used to release water out to sea. Which are used depends on the relative water levels inside and outside the barrage. Prevailing tidal levels and predictions based on statistical modelling are also considered.

On the morning of June 16, when Orchard Road was flooded, the gates, which take 20 minutes to open fully, were progressively opened from 8.30am, two hours before the flooding occurred.

'How the gates are operated would have to be decided by the water level both inside and outside (the dam), because if the water level outside is higher during high tide, then you have to start the pumps and pump water out. If it is lower, then the crest gates can be lowered,' Dr Yaacob explained.

'The triggering point would have to be done carefully because it will take some time, and if we do open up the crest gates, we have to ensure it is done correctly.'

He added that PUB, the national water agency, had achieved this balance correctly during the three recent flooding incidents, pointing out that downtown areas such as Chinatown and Boat Quay had been unaffected on each occasion during an intense downpour.

'PUB did this correctly in the last three incidents and because of this, none of the areas downtown had any floods.

'As to whether we could have done it for the Orchard area - we did, but do not forget the Marina catchment is a very large catchment,' he said.

It's time to start a proper investigation
Straits Times 20 Jul 10;

AS A concerned citizen watching the physical transformation of Singapore over the last 50 years, I have often wondered whether there are any downside risks that come with such development.

Our land mass has grown by an amazing 25 per cent in almost half a century to 775.5 sq km. In fact, the entire shape of Singapore has changed along with our ethnography, transportation and management of water resources, down to the way we work and play.

According to a study, Singapore's coastline has been strikingly transformed not solely by territorial expansion through land filling or reclamation, but also by the closure of the estuaries of the main rivers draining the interior of the island.

To what extent has such a closure and relentless construction contributed to the floods in recent years?

To what extent, too, has the loss of 40 per cent of our natural forests, from 37.8 sq km to 22.6 sq km between 1960 and 2006, affected the island's ability to absorb torrential downpours?

It would be unfair to pick on the PUB or hold drainage as the culprit for the flooding. Neither should we cite Typhoon Conson as being a possible cause for our floods. It is simply too convenient.

The Government should start a Commission of Inquiry to examine why the recent floods have been concentrated mainly in the central and southern parts of the island, whereas the northern, north-western and north-eastern parts have been largely spared.

Has this to do with the closing of the river estuaries and the massive construction and urbanisation in the city and the surrounding suburbs?

Until we arrive at a more multi-dimensional root cause for the problem, we will, at best, get only a piecemeal solution.

As a world-class city, we cannot afford to sink like Venice or swim like New Orleans.

Patrick Low

'While floods are inevitable, watching parts of the country submerged is not.'

MR TOH CHENG SEONG: 'The Ministry of the Environment and Water Resources and PUB should set up a task force to alleviate the problem. While floods in the tropics are inevitable, watching parts of the country, especially Orchard Road, submerged is not. Singapore is widely regarded as one of the most liveable cities in the world. The flash floods remind us that more needs to be done before we can live up to that accolade.'


'Could it be Marina Barrage?'

MR ONG TIONG MENG: 'I grew up when flooding was a way of life before the problem was solved some 20 years ago. Now the problem is back regularly. What has changed? Could it be the Marina Barrage? As an engineer, I would have thought that the discharge into the sea would be more efficient without the barrier. Despite the comment that there are six high-flow pumps that can discharge the water into the sea, I am less than sanguine. Perhaps PUB, the national water agency, should review its pump operations. Once heavy rainfall looms, the pumps should be started regardless of the level of water in the basin. This will lower the level of water in the basin and ease the flow of water from the drainage areas.'