04 December 2008

Faster, cheaper land reclamation in Singapore

By 2030, another 50 sq km is set to be added - so Singapore will have expanded by a quarter altogether.

An initiative by the Singapore Land Authority (SLA) and Jurong Town Corporation (JTC) will involve scientific analysis of the impact of waves on different stretches of the coastline and reclaimed land. Engineers will then determine the appropriate level of shoreline protection to be put in place for three months until a tenant takes over the land.

The first test case for the new approach is the reclamation that has been done for a mega shipyard in Tuas.

For every kilometre of shoreline of land reclaimed under the new approach for the shipyard, the Government saved five months in construction time and about $11.25 million in costs. The shipyard owner saved nearly three months in construction time and about $4.5 million.

SLA is the gatekeeper for all land reclamation projects in Singapore.

The full article is on the wildsingapore news blog.

Is it safe to move quickly onto reclaimed land?

From Singapore tremors raise fear of building on reclaimed land by Koh Gui Qing, Reuters 9 Mar 07.
"Reclaimed land is made up of sea sand, so buildings will be shaken up more violently during earthquakes as compared to those on non-reclaimed land, which is solid and will not be liquefied by the shake," said Fan Sau Cheong, an engineering professor at Singapore's Nanyang Technological University. He told Reuters that buildings on reclaimed land may shake two to three times more than those on natural land during earthquakes because sand in reclaimed land slides like liquid when saturated with water, in a process called liquefaction.
From Is Singapore quake-proof? Lin Yanqin Today Online 20 Jan 05
"Singapore stands on extensive soft marine clays and sands. You have massive cargo ports and harbours on reclaimed land," Prof Rice said. "I think you should put in place a set of studies to realistically assess the plausible size of earthquakes and the detailed response of structures in Singapore."

As Singapore's history does not go back long enough to document earthquakes which may have occurred centuries ago, it should not think it is immune to the threat of a major earthquake off Sumatra's western coast, Prof Rice said.

He likened Singapore to Mexico City, which was devastated by an earthquake in 1985 because it was built on the bed of an old lake.
What about sea level rise?

From Vulnerable to rising seas, Singapore envisions a giant seawall By Wayne Arnold, International Herald Tribune 29 Aug 07
Singapore got a preview of just what havoc rising sea levels could cause back in 1974 when a rare astronomical event caused the tides to rise 3.9 meters, more than double the usual level.

"It eroded the coast very badly," said Wong Poh Poh, an associate professor specializing in beach geography at the National University of Singapore, who studied the event.

Areas along the Singapore River were inundated, as were parts of the airport and a coastal public park built on reclaimed land. Wong later discovered that during such periods of elevated sea levels, the variations between high and low tide are accentuated, putting the country's reservoirs, many of which lie adjacent to the coast, at risk.
More background on reclamation in Singapore

From Singapore Finds it Hard to Expand Without Sand by Koh Gui Qing PlanetArk website, 12 Apr 05
Under a Concept Plan 2001, Singapore wants to add another 99 sq km (38 sq miles) over the next five decades. Civil engineers say that would be costly and require massive amounts of sand.

When reclamantion works began in earnest in the 1960s, the depth off Singapore's shore was about 5 metres (16 ft). That has sunk to about 20 metres (65 ft), requiring four times as much sand -- and four times more money -- to fill every square metre.

For a sense of scale, and cost, take Singapore's Changi Airport. Its 20 sq km (7.7 sq mile) of reclaimed land required 272 million cubic metres (9.6 billion cubic ft) of sand, said a civil engineering professor at a local university. The sand alone would have cost at least S$1.9 billion.

For now, Singapore may refocus on its own undeveloped land. About 41 percent of the island is either undeveloped or taken up by reservoirs, cemeteries, farms, army camps and nature reserves.
More links to land reclamation and shore protection in Singapore


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