SINGAPORE: Despite increased urbanisation and more variable weather, flood-prone areas in Singapore have been reduced from 3,200 hectares in the 1970s to 30.5 hectares today, said Minister for the Environment and Water Resources Masagos Zulkifli.
Speaking in Parliament on Monday (Feb 6), he noted that Singapore’s stormwater management strategies have served it well. He was responding to questions from Members of Parliament on the recent flash floods across the island, and what his ministry would do to reduce such incidents.
He said flood management has been made more challenging due to “upward trends in rainfall intensity and frequency of heavy rain events”, coupled with “growing urbanisation which increases stormwater runoff”.
Mr Masagos outlined the “source-pathway-receptor” approach taken by national water agency PUB to reduce flood risk. It addresses flood protection not just through drains and canals (the pathway), but also in areas generating stormwater runoff (the source) and areas where floods may occur (the receptor).
In terms of drains, Mr Masagos said that since 2011, PUB has raised drainage design standards for new developments and redevelopments. This would increase their drainage systems’ capacity up to 50 per cent.
Drainage improvement work at 192 locations has also been completed, he said, and there are ongoing projects at 90 other locations.
He added that PUB also requires developers to implement “source” solutions to better manage stormwater discharge from developments, while “receptor” solutions like higher platform levels, crest protection and flood barriers are also required, especially for critical installations.
Mr Masagos said PUB works closely with the National Environment Agency’s Department of Public Cleanliness to regularly remove debris, litter and leaves from drains. It also encourages the public to keep the environment litter-free and give feedback on drain conditions.
PUB also works with major development agencies to get their contractors to conduct checks on the public drains near their construction sites to ensure that the drains are free of debris, he added.
But even as PUB continues with efforts to reduce flood risks, Mr Masagos said it is not possible to eliminate floods altogether. “Our focus is also to help members of the public better manage floods when they occur,” he said, adding that PUB has put in place monitoring and alert systems to keep the public updated. PUB also works closely with the Land Transport Authority and police to monitor road conditions and provide real-time updates to the public.
Referring to recent flash floods at Upper Thomson Road, Mr Masagos said that unauthorised work by a contractor had affected the public drainage system. He explained that the floods were caused by a “localised constriction” at temporary diversion drains built by the contractor.
He said the contractor did not inform PUB before the commencement of work, and the public drainage system across Upper Thomson Road was also found to have been altered by the contractor without PUB’s approval.
“PUB takes a serious view of such unauthorised works and will not hesitate to take action against errant parties under the Sewerage and Drainage Act,” said Mr Masagos. “Such penalties and reputational damage, as well as being liable for civil penalties if they cause third-party damage, have been sufficient and effective in the past, and PUB will continue to review the amounts from time to time.”