Introduction

SINGAPORE - Singapore has been hit hard by flash floods, experiencing three significant episodes in just three months due to the ongoing north-east monsoon and record-breaking rainfall.

Recent Incidents

The latest incident unfolded on December 29, when areas including Dunearn Road, Bukit Timah Road near King Albert Park, and Balmoral Road were submerged in water. Many drivers found their cars stranded, as rising waters overwhelmed the streets.

Historic Rainfall Records

November 2023 marked a historic turning point, with the month becoming Singapore’s wettest since rainfall records began in 1980. Experts predict that this wet phase of the monsoon will extend through late January 2025. According to Mr. Maurice Neo, director at Singapore's national water agency PUB, "Predicting the intensity of these showers remains a challenge, as rainstorms can suddenly develop in Singapore's unique climate." He further explained that "extremely heavy rainfall in a short time can exceed drain capacities, leading to flash floods—localized floods that generally last less than an hour."

Response to Flooding

On the day of the latest flooding, PUB acted swiftly to assist motorists and property owners by relocating vehicles from floodwaters, pumping out water from basements, and distributing flood protection devices like flood bags and barriers.

Ongoing Weather Patterns

The rainy season isn't expected to relent anytime soon, as the La Niña phenomenon, known for its wetter and cooler conditions, is anticipated to return between now and March 2025. The Meteorological Service Singapore has placed the country on a "La Niña watch," raising concerns over prolonged periods of rain.

Climate Change Impact

According to Singapore's third national climate change study, climate change may intensify storms, resulting in more frequent and severe flash floods. Earlier incidents occurred on November 22, when heavy rain triggered floods in Yishun and Potong Pasir, and on October 14, which brought one of the heaviest downpours the western region has seen in over 40 years, flooding significant thoroughfares like Yuan Ching Road, Bukit Timah, and Tampines.

Rainfall Statistics

In total, these three rainfall events rank among the heaviest recorded since 1978, with December 29's rainfall of 134.6mm accounting for 41 percent of Singapore's average December rainfall and placing it within the top 1 percent of maximum daily records since 1978. Between 1981 and 2020 alone, more than 80 extreme rainfall events have been documented in the top 1 percentile.

Infrastructure Improvements

To combat flooding, significant drainage improvement works have been carried out along flood-prone areas like Bukit Timah, with ongoing efforts to enhance a 900-meter stretch of Bukit Timah Canal set for completion by 2026. However, officials acknowledge the limitations of merely widening and deepening drains, prompting more proactive public preparedness initiatives.

Public Preparedness Initiatives

In response to previous floods, PUB launched its first national campaign in November to educate the public on flood preparedness. The recent collapse of a brick retaining wall at two conserved terraced houses in Cairnhill Road amid heavy rain highlighted the urgent need for infrastructure resilience. The Building and Construction Authority (BCA) confirmed that the affected units are structurally sound, but they will mandate that the owners engage professional engineers for a thorough assessment.

Distribution of Flood Protection Gear

As part of their annual flood preparedness efforts, PUB distributes flood protection gear, such as inflatable flood bags and barriers, to homes and businesses located in flood-prone regions. By early November, around 16,000 protective items had already been dispersed.

Need for Enhanced Warning Systems

In light of these challenges, experts suggest enhancing early warning systems for extreme rainfall events requires a comprehensive approach to understanding the interplay of various climate influences across different scales. "Improving our data assimilation and modeling for urban environments is critical for effective early warning systems," emphasizes Assistant Professor He Xiaogang from the National University of Singapore.

Flood Prevention Tips for Homes

Regularly maintain drains to ensure they remain clear and functional.

Install flood barriers during high-risk periods to safeguard property.

Elevate essential belongings to higher ground.

Disconnect electrical appliances and turn off mains in case of evacuation.

Avoid handling electrical devices when wet or standing in water.

Conclusion

As Singapore grapples with the onslaught of heavy rains, it is clear that both infrastructural adjustments and public readiness will be crucial in mitigating the severe impacts of flash floods in the future.