SINGAPORE: Flash flooding of the intensity seen on Monday morning (Jan 8) will be better managed, once ongoing drainage improvement works are completed by the first quarter of 2019, said national water agency PUB.
“You can be very sure that when drainage improvement works are completed, the situation will definitely be improved,” said Mr Yeo Keng Soon, director of PUB's Catchment and Waterways Department following flash floods that affected many parts of eastern Singapore in the morning.
“The drains will be able to discharge more water in a shorter period of time (when works are completed)," he added. "(But) whether an area will be flood-free, we cannot promise that.”
During an evening media briefing, Mr Yeo said that drains in eastern Singapore were “overwhelmed” by the intense rain that fell on Monday morning, reiterating what PUB had said earlier in the day that about half of Singapore's average monthly rainfall in January fell in just four hours in the Kim Chuan Road area.
Preliminary investigations showed that the drains were running at 100 per cent efficiency, and there were no obstructions in the drains to have contributed to the flash floods.
“The drains were serving their intended purpose and function this morning,” said Mr Yeo. "But based on that kind of rainfall, it overwhelmed our drain design capacity.”
According to the National Environment Agency, the rain falling over eastern Singapore was due to the prevailing northeast monsoon, aggravated by the development of a Sumatra squall over the Straits of Malacca which moved eastwards due to changing wind direction.
A Meteorological Service spokesperson who was at the briefing explained that it is less common for a Sumatra squall to form in January, as it is typically seen between March and November.
PUB added that the tide level could have aggravated the situation at the nine locations where flooding was reported. Four of those locations lead to Bedok Canal and are subject to tidal influence.
PUB explained that during high tide, seawater can flow into the canal, but water levels are manageable without heavy rainfall. With a mid-tide level this morning, it could have aggravated the flooding at locations near Bedok Canal.
Eight of the locations where flooding occurred are where three main improvement works are ongoing, said PUB. The works are slated to be completed between the third quarter of this year and the first quarter of 2019.
With the exception of Tampines Avenue 12, the rest are low-lying areas. PUB said flooding in Tampines Avenue 12 could have been due to a "high slope" in the area which possibly caused rainwater to rush down fast enough to beat the threshold capacity of the drain.
MORE RAIN EXPECTED BUT HARD TO PREDICT INTENSITY
NEA said that while Singapore can expect more rain in the next few days, it is hard to predict the intensity of rainfall.
Meanwhile, PUB said it has measures in place to deal with a possible deluge, such as having contractors on standby to pump out water, should there be flooding in areas such as basement car parks. It has also been drawing on staff from its other divisions to standby for potential flooding during this period.
While it urged members of the public to be patient until drainage works are completed, PUB said they should also take precautions and keep themselves informed through the various platforms such as on radio and on PUB’s MyWaters mobile app.
It urged pedestrians to wait until floodwaters recede before venturing out, and for motorists to avoid flooded areas as their vehicles may stall once water levels reach a certain level.