MONDAY'S flash floods may not be the last to blight Singapore this year.
The Meteorological Service Singapore warned yesterday that short, moderate to heavy thundery showers are expected to become a regular occurrence during afternoons and evenings over the next two months as the annual north-east monsoon season takes hold.
They could even lead to floods such as the one in Kovan on Monday afternoon, when intense rain caused water from the canal to overflow into residential areas, trapping parked cars, causing power shutdowns and flooding homes.
The first half of this month has already been wetter than usual, with 188mm of rainfall recorded so far - and the meteorological service said it will only get wetter.
Rainfall this month and the next is expected to be about 20 per cent above the long-term average of 257mm and 288mm respectively.
The north-east monsoon season usually lasts from late November to January. It is expected to cause two to four monsoon surges - periods of occasionally windy conditions, cooler temperatures and prolonged and widespread moderate to heavy rain lasting between two and five days.
"In preparation for the upcoming north-east monsoon, PUB, the national water agency, (is working) closely with the National Environment Agency... to ensure that our drains remain free flowing," both agencies said in a statement yesterday.
It added that PUB officers will remind construction sites to conduct checks on nearby public drains. They will also inspect 100 major worksites to ensure that nearby drains are in order.
Meanwhile, the Singapore Contractors Association will send out circulars to its 3,000-plus members advising them to work closely with the authorities.
The PUB said it will also monitor its 171 water-level sensors in major drains and canals, and its network of 161 closed-circuit television cameras to enable quick response during heavy storms. It plans to increase the number of water-level sensors to 200 by the first quarter of next year. Last month, PUB officers also distributed advisories containing flood precaution tips - such as storing items on higher ground or using sandbags or flood boards - to 500 residents and shop owners in low-lying areas.
Areas which have previously experienced flash floods have already put safeguards in place.
Singapore Polytechnic has taken measures including the installation of flood walls and warning sensors after floods disrupted classes in February last year.
Liat Towers, which was deluged by waist-high water in 2010, has installed six water pumps and erected flood barriers, among other measures.
Civil servant Dawn Koh, 22, said her Opera Estate backyard floods every time it rains heavily.
Her family has installed non-slip tiles, covered furniture with plastic and piled up sandbags. She said: "The drainage system in the neighbourhood is not very good and we get flooded often."
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