Singapore's Flood Resilience Plans

Mr Seng Han Thong asked the Minister for the Environment and Water Resources (a) if he will give an update on PUB's action plan to strengthen Singapore's flood resilience; (b) whether the action plan that covers the entire spectrum of drainage and flood management has worked or not; and (c) whether it needs further enhancement in the larger context of long-term plans in view of global climate change.

Mdm Speaker, the increasing frequency of high-intensity storms as well as the progressive urbanisation of our landscape has posed challenges for the management of flooding in Singapore.

My colleagues in the Public Utilities Board (PUB) have been very busy over the last few years. PUB adopts a comprehensive "source-pathway-receptor" approach to preventing and mitigating floods. This involves measures, first, to reduce the storm water run-off, that is, at the source itself, where the rain falls; second, to enhance drainage capacity, that is, to increase the flow within the drains; and, third, to reduce the flood risks at vulnerable low-lying areas.

Since 2011, our drainage design standards have been changed and they have been raised by between 15% and 50%, depending on the size of the catchment. PUB has, therefore, been carrying out an island wide drainage improvement programme to enhance the capacity of all our canals and drains to meet these new standards. That is why many of you would have noticed that there is a lot more work going on in drains, I am sure, even in your own local neighbourhoods over the last three years.

In fact, since 2012, drainage improvement works at 187 locations have been completed. Ongoing, currently, is work at another 115 locations, including the Stamford Detention Tank, the Stamford Diversion Canal and the Bukit Timah First Diversion Canal. This year, drainage improvement works in an additional 19 areas will also commence and these include improvement works to Tampines Canal to alleviate flood risks along Tampines Road itself as

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well as new drainage infrastructure in Marina South to serve upcoming developments in that area.

To reduce run-off "at-source", all new developments or redevelopments of 0.2 hectares or more since January 2014 have had to control the peak run-off entering the public drainage system. Developments can achieve this by implementing on-site detention or retention measures in order to reduce the peak run-off, which means, when the rain falls, it does not immediately enter the public drainage system. To date, about 75 developments have submitted plans that have incorporated such on-site features.

At the "receptor" level, PUB has raised the requirement levels for platform and crest levels for all new developments and redevelopments since 2011. This is to provide an additional safeguard against future sea level rises. PUB has also been working with specific building owners to provide technical advice on relevant receptor solutions such as flood barriers and road crests, where necessary.

In addition to all these structural enhancements, PUB has also instituted measures to help the public better prepare for floods. PUB has a network of 171 water sensors installed in all the major drains and 161 closed circuit televisions (CCTVs) installed at flood-prone areas in order to provide remote monitoring of drain and flood conditions at critical junctions. All this data is available publicly in real time. If you use any of the apps from my Ministry, you will be able to see the video feeds in real time. The drain sensors are tweeted in real time also, if the water levels reach significant points.

Since August 2011, PUB has also instituted a free SMS alert system to provide early warnings of heavy rain and rising water levels in canals to members of the public who subscribe to this free service.

Our approach to flood management and to tackling storm water at the source, pathways and receptors, has served us well over the last few years. It is too early to declare victory but we have made progress and I would say my colleagues are cautiously optimistic. We will continue to work hard and, over time, the results will speak for themselves.

Mdm Speaker, I thank the Minister for his cautiously optimistic answer and for the hard work by the PUB. And, really, this time round, we did not suffer any flooding in the Orchard Road area, not even ponding. May I ask whether there are other initiatives besides the recommendations of the expert panel in 2012?

We have substantially implemented all the recommendations that were put up by the expert panel. We are actually projecting a future with even greater

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challenges. As global climate change occurs, we anticipate further rises in sea levels. We also anticipate more intense storms. So, even the levels of drainage standards we have imposed now may not be adequate for the future. So, this is an ongoing programme. Members will also appreciate that these are major and expensive works and they are disruptive. So, we have got to phase them out and ensure that we do not unnecessarily disrupt lives or spend too much money in advance of those needs. So, there is an element of judgement needed.

I will just give Members a figure, so that you can get an idea of it. If you go back to the 1970s, Singapore had about 3,200 hectares of low-lying flood-prone areas. Today, the flood-prone area has been reduced to about 34 hectares; 3,200 hectares to 34 hectares. But to reduce 34 hectares to an even smaller number, it is like ascending the last bit of the mountain. It will get progressively more difficult. But we make this commitment that we will be open and we will acknowledge problems. That is part of the reason for our tweets on drains, that is, to send a message to the people that we will not ignore problems, we will be completely open and forthright about them.

The other point is that we have a simple heuristic within PUB. If an area has had a flood, we will conduct a full investigation, identify the source, if need be, upgrade the drain. You will see continuous improvement. If any of you have got any specific concerns in your respective areas, please let us know.