Following a prolonged downpour on Saturday (17 Apr) afternoon, flash floods were reported in several parts of the city-state, resulting in slow traffic and tree falls.
National water agency Public Utilities Board (PUB) said in a Facebook post that the heavy rainfall had caused the water levels in a number of drains and canals to exceed 90 per cent of its capacity.
It also issued flood risk warnings for over 20 locations across the island.
The locations include the Bukit Timah Canal near Leng Kwang Baptist Church, and Sungei Pandan Kechil near the National University of Singapore and the Ayer Rajah Expressway.
Flooding was also observed on the pedestrian sidewalks along Dunearn Road near Sime Darby Centre, and the Park Connector along Ulu Pandan Canal — a result of “high water levels in adjacent drains and canals”, said PUB.
However, PUB’s Quick Response Teams were immediately deployed to the locations above to render assistance to drivers and pedestrians, said the Board.
The national water agency also stated that Saturday’s rainfall was the heaviest rainfall of 161.4mm recorded in western Singapore, lasting from 12.25 pm to 3.25 pm that day.
This amount corresponds to 91 per cent of the country’s average monthly rainfall in Apr and lies within the top 0.5 percent of Singapore’s maximum daily rainfall records since 1981, according to PUB.
CNA reported that slow traffic was seen on the flooded roads. One resident living along Jurong East Street 32 told CNA that the area has “never been flooded like this before”.
The man also noted that the police had cordoned off the area to stop cars from passing through, adding that a bus was seen moving along the area “very slowly”.
Trees fell due to downpour
Separately, the heavy rain also caused trees to fall. The Straits Times (ST) reported that a tree branch fell onto a green car, smashing its windscreen.
It added that the police arrived and towed the car away at around 3.20 pm.
Another tree fell at Block 166 Bukit Batok West Avenue 8, Mothership reported.
On Friday (16 Apr), the Meteorological Service Singapore stated that there would be more rain in the next two weeks, with thundery showers and gusty winds predicted for the earlier part of the fortnight.
The storms are expected to occur before dawn and later in the morning and are due in part to a large-scale convergence of winds predicted to develop over the region in the next week.
Additionally, lighter winds are expected during the latter part of the two weeks. Despite that, moderate to heavy thunderstorms with frequent lightning strikes in the afternoon may take place during the said period.
Overall, the Meteorological Service said that the rainfall in April is predicted to be above average over most parts of the island.
Not practical to expand drains for every downpour
In 2020, the then-Minister for Environment and Water Resources Masagos Zulkifli said in a written parliamentary reply that it is not practical for the Government to expand drains in the country every time a heavy downpour occurs.
“While PUB will continue with efforts to improve drainage system, it is not practical to expand our drains to meet every extreme rainfall event in land-scarce Singapore,” said Mr Masagos.
He added, “Besides drainage improvements, PUB will put in place cost-effective measures to minimise flood risks and better manage flood events. For instance, PUB is in the midst of upgrading its rainfall forecasting radar technology, which will help improve prediction of locations where heavy rainfall might occur and enhance its response time to potential flash flood.”
Mr Masagos said this in response to a question raised by People’s Action Party’s (PAP) Sitoh Yih Pin on what are PUB’s plans to further tackle flash flood issues in Singapore after several parts of the island experienced sudden flooding due to heavy rainfall in April 2020.
“As part of PUB’s broader efforts to address the impacts of climate change, PUB had raised the drainage design standards to cater to higher rainfall intensity in 2011. Since then, the Government has invested almost $2 billion in drainage works, and will invest another $190 million this year to enhance our flood resilience,” the MP explained.
Rapid urbanisation major factor behind flash floods, netizens say
Over on social media, online users were quick to observe how Singapore has undergone rapid urbanisation leading to a poor drainage system, which then leads to flash floods during heavy downpours.
One user highlighted how the Government had spent so much money and time trying to resolve flooding issues for decades but to no avail.
“Even if we have so many reservoirs to hold the rainwater, flash floods will still occur unless we can find a way to slow down the drainage process with more greenery (marshland and swamps or naturalising existing canal systems like the one in Bishan-Ang Mo Kio Park to hold the rainwater temporarily,” one commenter suggested.
Some opined that flash floods occur due to climate change.
However, others said that water from the flash floods will not go to waste, as it will be stored in the country’s reservoirs and will come in handy for future use.
Separately, one user questioned the Government’s plans to expand the drains in Singapore.
Another user stated that the underground network system built to store rain water and contain flooding is not working.
The user added that the underground system might also not be well connected, not properly maintained or there are wrong guidelines for underground drain activations in place.
One user suggested putting a stop to all construction works and said current projects should be completed first. Additionally, no new projects should commence to prevent further potential damage.
“Also, go through all the projects that were done during the last 18 years and diagnose the possible problems that were not thought out during planning,” the user said.