450m stretch of Dunearn Road to be raised to reduce flood risk

National water agency PUB will be raising a 450m stretch of Dunearn Road, where flash floods have occurred three times this year, to reduce the risk of such incidents there.

The works are expected to be completed by November this year, PUB said in a statement yesterday.

The Sunday Times understands that road raising typically involves layering premix to increase the road level. This helps to reduce the depth of floodwaters on the road.

Details on how high the road will be raised are still being fine-tuned.

The raising of the road will be an interim flood-proofing measure before ongoing drainage expansion works in the Bukit Timah area are completed by the first quarter of 2024.

PUB said the drainage improvement project to widen and deepen a 900m section of the Bukit Timah Canal will help to address the problem.

Last Tuesday, heavy rain caused a flash flood that resulted in the stretch of Dunearn Road between Sime Darby Centre and Binjai Park becoming impassable for about 40 minutes.

That day, more rain pelted western Singapore in three hours than the average rainfall for the whole month of August.

On July 12 and April 17 this year, heavy rain also caused flash flooding incidents there.

The recent heavier-than-usual rains were caused by multiple weather events. One of them is "a very active wet phase" of the Madden-Julian Oscillation, said the National Environment Agency's Meteorological Service Singapore.

This oscillation refers to a moving pulse of rain clouds that usually moves eastwards over the Equator.

At the same time, the effects of another climate phenomenon known as the Indian Ocean Dipole (IOD) are also being felt here.

The IOD is now in its negative phase, with changes in sea surface temperature and winds over the Indian Ocean bringing more rain over Singapore.

With more rain on the cards, some residents in flood-prone areas are taking steps to ensure they are not caught flat-footed again.

Mr George Lim, who lives in Eng Kong Place near the Sime Darby Centre, said his family has hired a contractor to build a ledge to prevent water from entering the house through its full-length window.

Mr Lim, who helps to run his family's carton box business, told The Sunday Times that last Tuesday's flooding incident was the most severe one experienced by the family.

"Previously, the water would reach only the car deck, but this time, it entered the house," said the 27-year-old.

Other residents said they were stuck in traffic and had to wade knee-deep in muddy water, while those at home during the downpour scrambled to save their furniture and shoes from being swept away.

One Eng Kong Place resident, who wanted to be known only as Mrs Yeo, said her family's electronic devices, including a modem, were damaged as a result of the heavy rain.

The 52-year-old housewife also had to throw away her living room carpet, which she said had cost thousands of dollars.

Others like retired businesswoman Tan Koy Choo, 67, decided to make the best of the situation.

The avid gardener, who lives in Toh Tuck Drive, has collected about 30 15-litre containers of rainwater over the past week.

She is using it to water her plants and clean her home, which she shares with nine other family members.

Holland-Bukit Timah GRC MP Sim Ann urged residents to subscribe to PUB's flood alerts, while her fellow MP for the area, Mr Christopher de Souza, asked those who needed help to come forward.

Bukit Timah residents told The Sunday Times that PUB distributed self-inflating sandbags that can absorb water in the event of another flooding situation.

But some business owners said that by the time such damage control is taken, it is too late for some of their products.

Ms Lynne Chong, 52, who co-owns Peranakan eatery Nonya Delicatessen in Bukit Timah Plaza, which was flooded last Tuesday, said the water damaged the flooring and merchandise in some shops.

A PUB spokesman told The Sunday Times that its officers actively assist and give advice to building owners and residents on managing flood risks for properties located in flood-prone and low-lying areas.

This includes installing additional flood protection measures such as humps and permanent flood barriers to protect basement levels from floodwater, as well as alarm systems to provide early warning on flooding.

He added that PUB has successfully trialled various types of portable flood barriers and flood panels, which it lends to residents and business owners.