Oversea experts comment on Singapore flood measure

SINGAPORE: The panel of experts appointed to review Singapore's flood protection measures submitted its report on Tuesday, after a six-month consultation period.

It proposed that national water agency PUB collect high-resolution data to get a better idea of Singapore's flood modelling profile, and the government look into new ways to tackle the surface runoff upstream rather than focus all efforts on the downstream.

The panel said a general widening of drains and canals in Singapore is not the best long-term solution for flood prevention. This holds true for the Stamford Canal which, the panel noted, had been designed to the standards in place at that time rather than standards more typical today.

It said the canal no longer has the capacity to drain away the volume of rainfall generated by storms like those in June 2010 and June 2011.

The panel does not believe that the whole-scale upsizing of the Stamford Canal is the best long-term solution to addressing flood risks on Orchard Road.

It suggested the government look into ways to store water in the Orchard Road area further upstream, such as through the use of roof tops, a water retention pond, storage tanks along the Stamford Canal's route to relieve its burden or a diversion canal to bring the water elsewhere.

New buildings should have water-retention roofs to make up for increased urbanisation and existing buildings should be retrofitted, said the panel.

Pavements could also be made porous to absorb some water and preventing all of it from rushing into canals, added the 12-member panel comprising local and international experts.

These measures control flooding at the source, said a member of the panel, Professor David Balmforth.

The panel acknowledged that these measures and the gathering of more accurate higher-resolution data on water drainage will require significant investment.

But Professor Balmforth, MWH UK's executive technical director, said: "What the experience in the rest of the world shows...is that the overall cost of doing it that way is generally significantly less than if you concentrate on trying to increase conveyance capacity all the time."

The panel said Singapore should also look into drainage systems that can deliver multiple benefits, for instance, water storage solutions that can serve as a source of water in times of drought.

The panel was appointed on June 30 last year to review drainage design and flood protection measures that will be implemented in Singapore over the next decade. It is chaired by Professor Chan Eng Soon, dean of the faculty of engineering at the National University of Singapore (NUS).