The national water agency PUB has come up with an interim solution to solve the flood problem on the Ayer Rajah Expressway (AYE), one day after flash floods forced the expressway to be closed during the morning rush hour.

PUB will build a tidal gate at Sungei Pandan Kechil canal, which can prevent high tide from the sea from flowing into the canal.

Director of catchment and waterways PUB, Tan Nguan Sen, told The Straits Times that the tidal gate can stop the influence of the tide, and help to buy time for the water to dissipate during heavy downpour.

PUB has pointed out that the combination of heavy rain and high tide were the reasons behind the flash flood. In addition, the AYE sits on a junction where three drains meet.

Mr Tan added that as each drain comes from a different direction, the intersection has a lot of resistance, which in turn slows down the rate of water flowing through.

The agency will also widen the culverts at the intersection to allow more water to pass. Works will start by the end of this month and is expected to complete by end of next year.

Considerations were given to widen and deepen the canal, and to build a barrage - a larger version of the tidal gate - as plans for the long term. But Mr Tan said these projects will require more research and time to plan.