Historical data down the drain in flood prevention

Straits Times 3 Jul 10;

THE water authorities can no longer rely on historical data when planning the infrastructure needed to deal with extreme weather, says the head of a major water company.

Mr Daniel McCarthy, president and chief executive officer of global water company Black & Veatch, which helped with the installation of Changi's Newater plant and the development of the Marina Barrage, said that the old method of predicting rainfall is no longer valid.

'What we are seeing is higher intensity storms and longer periods of drought,' he said at the Singapore International Water Week, which ended yesterday.

'Traditional engineering solutions look at historical weather patterns and extrapolate forward.

'It's not working.'

He called for a new standard of planning, taking into account new weather patterns and rising sea levels, the latter of which is of particular concern to island nations like Singapore.

'Although no one can predict the weather, there are new tools to help us look at scenario planning and what extremes will look like as we can't look at past averages,' he said.

While Mr McCarthy said it was not possible to be rid of the risk of flooding, better management could mitigate the problem.

'I don't think we can build everything for a worst-case scenario, as it's too expensive, but we don't want to deny ourselves solutions like putting in a second pipe or drain if water flows increase,' he said.

He added that rain gardens and porous concrete can be used to help slow the run-off from concrete, while detention basins can stem the flow of sudden downpours of the type seen recently in Singapore.

Singapore's water authority, the PUB, is currently reviewing all major canals and how they are cleaned and inspected following the Orchard Road floods last month, which caused millions of dollars worth of damage.

It is not known when the results of the review will be published.

VICTORIA VAUGHAN

Invest in water management to avoid flooding
Straits Times Forum 3 Jul 10;

WITH reference to Monday's report ('PM: Don't expect flood-free Singapore'), Singapore sits near what has been the southern edge of the North-Equatorial band of the Intertropical Convergence Zone, about one degree north of the equator.

Data from three American solar observation sites - Mauna Kea, Kitt Peak and White Mountain - confirm that there has been a sharp drop in net solar heating since 2008. This may be a trend that is going to carry on for several decades; a reversion to the mean after an unusually active solar period in the late 20th century.

The reduced heating - a spectral shift due to less infrared 'light' from sunspots - has narrowed the zone and moved the centre from plus or minus three degrees to about two degrees latitude. It has also expanded the earth's 'dry bands' centred about 20 degrees latitude.

The results are rising rainfall in the narrower zone (for example, in Singapore) and less rainfall in the dry bands (for example, in Hawaii and Mexico). With a growing population, water may become more important than oil as a strategic resource for ensuring not only prosperity, but also survival.

So, Prime Minister Lee Hsien Loong is generally correct. Singapore must invest in water management systems that can handle higher volumes of water to avoid flooding.

Brian Lynch
Austin, Texas

'Growing urbanisation has radically reduced the capacity for natural, sustainable drainage.'
Straits Times Forum 3 Jul 10;

MR MICHAEL LAZAR: 'Prime Minister Lee Hsien Loong is right ('PM: Don't expect flood-free Singapore'; Monday). It is not economically possible and sustainable to upgrade the drainage system to keep up with the storm water run-off. However, with growing urbanisation, the increase in hard landscaping, footpaths, cycling and jogging tracks, housing estate roads, parking areas and such has radically reduced the capacity for natural, sustainable drainage. This, coupled with the changes in rainfall patterns, means continuing growth in the volume of surface water run-off that has to be managed. Designers, developers and the approving authorities should assess the impact of their projects on the existing hyrology and of their drainage system for extreme events and climate change.'

Public has role in preventing floods
Straits Times 3 Jul 10;

I AM astounded by the number of complaints in the Forum page about the recent freak flood in Singapore. They demanded explanations from the PUB despite the quick action taken by the national water agency.

We should understand that the recent heavy rain was due to global warming. Almost every major city has been hit recently, and floods have caused far more serious havoc in these places than what we have seen here.

The sudden and exceptionally heavy rain within a short time in Singapore was an act of God and is impossible to foresee and avoid.

The authorities have said enough and we should do our part to prevent flooding, instead of complaining. We should stop littering and ensure our drains are kept clean.

I noticed that most of the complaints were about loss of business and costs associated with it. In good times, do these people appreciate the safe and secure environment that allows them to thrive?

Peter Khaw