Are porous roads the way to deal with floods in Singapore? [News]

October 7, 2011 by Eugene Tay
Filed under News

By Esther Ng, Today, 7 Oct 2011.

Porous roads and using basements to store storm water are some ideas being bounced about by an expert panel formed to improve Singapore’s flood protection measures.

Other recommendations include combining predictions on rainfall intensity and trajectory with rain gauges and water level sensors installed in canals, which will result in a real-time flood alert system that would “allow the agencies to give a better lead time to the community”, said Professor Chan Eng Soon, who chairs the panel. He was giving an update yesterday on the panel’s work since it was formed in July.

Among its preliminary recommendations, the panel said: “PUB should move to a process of new generation drainage systems models that can adequately replicate systems performance, evaluate potential interventions and provide flood-risk mapping.”

Meeting for five days from Sept 26 to 30, the panel also proposed holistic flood control measures such as tapping and reusing storm water to flush toilets.

“The question is not just on collection, but the infrastructure that goes with it,” Prof Chan said. For example, households will need separate pipes connected to a storm water tank and that would incur cost.

As for porous roads, there is the question of cost of building infrastructure of pipelines.

“In the past, perhaps there was more emphasis on conveyance, (but now), the solution is not just a canal, but a system of canals and ponds and other things you can put in place to manage storm water,” Prof Chan said, adding that the PUB was familiar with these various approaches.

Asked what constraints national water agency PUB faced in implementing these ideas, Prof Chan, who is also the Dean of the Faculty of Engineering at the National University of Singapore, pointed that PUB had done much to reduce flooding “drastically” with the Bukit Timah “bypasses” and that the recent floods only happened in the last two years. “So all along (the measures) seemed to work very well,” he said.

In addition, the PUB has proposed an increase in design standards through the revised Code of Practice on Surface Water Drainage, and in terms of storm drainage, Singapore compares well to other metropolitan cities, he added.

Going forward, the panel recommends that the agencies take a “risk-based approach” of quantifying of the options and the cost of infrastructure, guided by potential implications of climate change and the use of comprehensive modeling and scenario analysis.