Shielding Singapore from rising sea levels

New structures aimed at protecting areas from storm surges could have multiple uses

- Shabana Begum

From the 2030s, three novel structures that will protect Singapore from rising sea levels will start to take shape on the nation's southern coast.

Called coastal barriers, these arm-like gates can open and close depending on weather conditions. It is the first time that such a coastal protection solution — a Dutch innovation — will be implemented in the Republic, national water agency PUB announced in end-August.

In response to The Straits Times' queries on how such a barrier would be operated, Professor Bas Jonkman from Delft University of Technology in the Netherlands cited the example of the Maeslant Barrier in Rotterdam, pointing to how the public is alerted to the barrier closure at least 12 hours ahead of time.

"The warning needs to give sufficient time for vessels to move, and advanced forecast models are in use for this," he said.

He added that many vessels move out of the Rotterdam port ahead of an incoming storm as it is safer in the ocean.

At the port, there is a higher risk of collisions with waterfront structures and other ships.

The closure of the gates themselves could take about two hours, and they remain closed "for several hours to stop the peak of the storm surge", said Prof Jonkman, who is also a member of PUB's Coastal Protection Expert Panel.

Coastal barriers are aimed at protecting an area from storm surges — higher-than-usual tides caused by storms brewing offshore.

By 2100, average sea levels around Singapore could rise by up to 1.15m. Storm surges can add another increase of 3m or 4m and cause coastal flooding if the shores are not protected.