Ensuring Essential Services are Not Affected by Flash Floods

To prevent and mitigate floods, PUB adopts a comprehensive "source-pathway-receptor" approach that covers Singapore's entire drainage system, addressing flood protection not just along the drains and canals through which stormwater travels, but also in areas generating stormwater runoff and areas where floods may occur.

To this end, PUB has an island-wide drainage improvement programme to enhance the capacities of our drains and canals. These pathway measures will ensure that our land and facilities for the essential services remain adequately protected against floods.

To further increase our flood resilience, since January 2014, all new developments and redevelopments of 0.2 ha or more are required to control the peak runoff entering the public drainage system. These source measures will improve the flexibility and adaptability of our drainage system to cope with higher intensity storms.

Finally, on receptor measures, PUB's Code of Practice on Surface Water Drainage specifies minimum platform level requirements for all developments. In particular, PUB sets higher platform and crest level requirements for critical installations, special facilities and developments with linkages to underground facilities, such as an underground MRT station. These measures will prevent flood waters from directly entering the facilities and causing disruption to essential services.

Beyond structural enhancements, PUB has instituted measures to help the public, including essential service providers, better prepare for flash floods. PUB has a network of about 200 water level sensors and 170 CCTVs installed to remotely monitor drain and flood conditions. This information is freely available on PUB's website, social media platforms and mobile apps. Since August 2011, PUB has also implemented a free SMS alert system to provide the public with early warnings of heavy rain and rising water levels in canals.

Our holistic approach to flood management has served us well. Despite increased urbanisation, flood-prone areas have been reduced from 3,200 ha in the 1970s to 32 ha today. However, with climate change, we can expect to experience more extreme and unpredictable weather; from more frequent and intense storms, to longer and more severe dry spells. There is a fine balance we need to maintain in the face of climate change. PUB will continue to put in place measures to minimise flood risk on one hand and strengthen the drought resilience of our water supply on the other.

I thank the Senior Minister of State for the answers. My question actually arose because I read that there were certain reported cases of flash floods occurring near hospitals. That is the background.

I have three supplementary questions. One, have there been any known cases so far where essential services have been disrupted due to flooding? Two, is there a protocol in place to inform emergency vehicles early on if their route has been affected by flooding? Three, are there any measures which can be taken to minimise the need to divert emergency vehicles, as diversion may lead to time delays, if they have to go to another hospital?

I thank the Member for his three supplementary questions. Firstly, let me say that flash floods are a result of rainwater overwhelming the drainage system. I have gone through the records of the recent flash floods in the last couple of years and most of the flash floods receded within 30 minutes. Obviously, that is not to say that we do not acknowledge the inconvenience and delay that might be caused. But generally, whilst there might be delays or some cars might be stranded, public transport had not been affected – that means, buses and all that. Even though there is a Standard Operating Procedure (SOP) for diversion, we have not had to do this for the incidents involved.

As to the question about known cases where emergency vehicles were delayed or diverted, I do not have information with regard to that. As I have said, I have checked and essential services had not been disrupted, including public transport.

Whether there is a protocol, PUB works very closely with LTA, SCDF and all the other agencies. In fact, once the Meteorological Services of Singapore (MSS) puts out an alert of a heavy storm, PUB's flood monitoring operations will kick in. As I have said, we have got water sensors as well as CCTVs. We also have access to LTA's CCTVs to monitor the situation and to give alerts in advance through social media websites, mobile apps, as well as on our PUB website. There is also a free SMS alert system. SCDF services would also utilise this to make sure that if there are any issues about flash floods in various areas, they will be aware of it.

Can the hon Member remind me what was the third question?

The third question is: what are the measures which can be taken to minimise the need to divert emergency vehicles, as diversion may lead to more time delays?

Yes, I think I have answered that. Actually, the flood monitoring operations kick in and there is an operations centre. In fact, the public can also use our PUB-One hotline to inform us of any flash flood incidents that they may be aware of and, in the spirit of the Minister of State Mr Sam Tan, let me publicise PUB-One's hotline, too. In fact, it is very easy. It is just "1800 Call PUB" or 1800 2255782.

I would like to ask the Senior Minister of State whether she is aware of any cases where access to hospitals has been disrupted by flash flooding and, if so, how long those cases took to recede. The purpose of asking that is just to assess the risk to accessibility to our hospitals in future, whether there is a risk of an extended blockage of access to hospitals due to flooding.

I think I have answered those questions. I said that based on the information I have − and I have actually made the effort to check through the records of flash floods that occurred over recent times − I do not have any information of access being blocked. It could be that there might be some ambulances which decided, because of the warnings that we had, to take a different route. But I do not have the information. As far as I am concerned, there was no blockage to access to hospitals. I do not have such information.

As I have said, we have advance warnings to the public and we also work very closely with SCDF, LTA and all the other agencies.