Singapore remains well prepared against coastal erosion: experts

Tan Qiuyi Channel NewsAsia 14 Jul 12;

SINGAPORE: A new US study said global sea levels could rise two to three times higher over the next century than was previously estimated.

But experts and authorities here said Singapore remains well prepared against coastal flooding.

Flash floods in Singapore's central shopping district in recent years were caused by heavy rain.

But experts said the effect of a coastal flood is similar.

Wetland Scientist at the National University of Singapore Dr Daniel Friess said: "A coastal flood is basically an unexpected high tide. You've got elevated tides, elevated waves. They're all going to contribute to a surge of water in low lying areas by the coast. The impact of a coastal flood is in many respects similar to an inland flood where you have a large body of water flooding shops and businesses and residences, you also often experience a lot of erosion on the coast."

With new data on the melting of polar ice caps, a new US National Research Council study predicts global sea levels could rise between 50 and 140 centimetres by the turn of the century.

That's higher than the 2007 UN estimate of between 18 and 59 centimetres.

The National Environment Agency's study that same year had predicted that the mean sea level around Singapore would rise slightly more - between 24 and 65 centimetres by 2100.

Local experts said there's no need to panic.

Principal Project Manager, Coastal Management, Building & Construction Authority, Ho Chai Teck, said: "About 70 per cent of the coast line is already protected by hard structures like sea walls or stone embankments, which help protect against coastal erosion. For these structures we're cautiously optimistic that they will continue to function well and protect us against any phenomena in the near term."

Since 1991, all reclaimed land on the island had to be built at least 1.25 metres above the highest tide level.

In 2011, this was raised to 2.25 metres.

Dr Daniel Friess said: "Certainly all new reclamations are going to be more resilient to sea level rise, so there we need to focus our efforts on reclamations conducted previous to 1991. I'm sure those are well protected with other adaptations. Not just how high you build your reclamations but also adequate drainage, pumps, things that help you react very quickly to a coastal flood."

Ho Chai Teck, said: "Those areas that could be at risk, would be the unprotected areas like the sandy beaches, mangrove areas or other natural coastal jungles or forest where further understanding and analysis will be required."

Mr Ho's team is closely monitoring beaches like East Coast Park, and adding to its defences.

Two years ago, they added "geo bags" to one eroded stretch of the beach, near the Road Safety Park.

Geo bags are a type of sandbag made of a special sticky material that sand can adhere to.

Apart from successfully building up beach two years on, the sandy surface of the bags also help them blend naturally into the beach front.

At another stretch of beach not far from the Bedok Jetty, the situation two years ago had called for a more drastic measure.

Proximity to the road makes the stretch of beach particularly narrow, which explains why it's especially prone to the ravages of the water, which just two years ago had washed away a significant part of the beach. Today, the beach is protected by a stepped sea wall.

Apart from protecting the beach, the steps of the sea wall have also become an effective resting spot for park users today.

With the "hard" structures already in place, experts are closely monitoring the impact of rising sea levels on the most bio-diverse of Singapore's "soft" coastlines - its mangrove forests.

The Building and Construction Authority said it has started risk-mapping in 2010.

The aim is to identify coastal areas at risk of erosion or flooding, and the damage that could come with it - including the loss of biodiversity.

Results are expected in 2013.