Such bouts of intense rainfall are expected to become more frequent with climate change.
National water agency PUB has come up with a number of strategies to reduce the likelihood of heavy flooding.
Here are some examples.
Catchment-level detention tanks
• PUB currently manages two detention tanks, the Stamford Detention Tank and Opera Estate Pumping Station, which have a capacity of 38,000 cubic m and 15,000 cubic m respectively.
• A third such tank in Syed Alwi Road is due to be completed by 2025. It will have a capacity of 9,300 cubic m.
Detention tanks
• Detention tanks collect and store stormwater run-off during a storm.
• They then release it at controlled rates into the drainage system, reducing peak discharge rates.
Minimum platform and crest levels
Elevating the entrances of buildings and MRT stations to prevent stormwater from flowing into them.
Rain garden
• Helps cleanse water that flows into drainage system by filtering.
• Slows down the speed of run-off entering drainage systems
Canals and drains
• Singapore currently has about 8,000km of drains, rivers and canals.
• If necessary, they can either be widened or deepened, or new infrastructure can be built.
<p>ST20201216-202081907133-Lim Yaohui-pixcovid17/</p>
<p>Workers doing grass cutting inside the canal of Serangoon River near Defu Lane 10 and Hougang Avenue 3 on Dec 16, 2020.</p>
<p>There were 12 new coronavirus cases confirmed as at Wednesday noon (Dec 16), all of which were imported. The new cases were placed on stay-home notice on arrival in Singapore, said the Ministry of Health (MOH).</p>
<p>Globally, the virus outbreak, which began in December last year, has infected more than 72.8 million people. More than 1.6 million people have died.</p>
<p>(ST PHOTO: LIM YAOHUI)</p>
PHOTO: ST
Flood barriers
Can be quickly deployed to protect homes and buildings in the event of a flash flood.
Green roofs
Rooftop vegetation captures rainwater, allowing evaporation and transpiration to take place, and reducing the amount of run-off entering drainage systems.
ST20210202_202129217336: Gin Tay/ Clara Chong / cckeppel
A member of the media touring the Green Roof (right) and Cascading Water(left) at the Keppel Marina East Desalination Plant (KMEDP) site during the media preview on Feb 2, 2021.
PHOTO: ST
Despite these efforts, why do flash floods still occur?
• Intensity of the storm can be much more than what the drainage system is able to handle.
• Options to reduce flooding may be limited in low-lying areas, as drains cannot be dug deeper than downstream levels, which will prevent water from flowing away
• Due to land scarcity, it is not practical to build bigger drains to meet every extreme rainfall event in Singapore.
