Deep below a Singapore island, the Jurong Rock Caverns provide storage for petrochemicals, freeing land above for more industrial uses. JTC Corporation

A wave of construction below the earth’s surface aims to make room for the city above.

SINGAPORE—Pipes and storage tanks cover most of heavily guarded Jurong Island, the heart of Singapore’s petrochemical industry. Singapore does not produce a single drop of oil, but the refineries owned by Shell, ExxonMobil, Chevron, and others on the man-made island account for about one-third of the city-state’s manufacturing output.

Land for the industry to grow on Jurong’s 12 square miles (31 square kilometers) is limited. So Singapore has begun looking underground for room to expand. About 500 feet (150 meters) down, deep beneath the seafloor, lies the recently opened Jurong Rock Caverns. It’s a massive storage hub for liquid hydrocarbons, as tall as a nine-story building and with several miles of tunnels.

Construction began in 2007. Ammonium nitrate was used to blast away sedimentary rock, and the cavern walls were then coated with a liquefied cement and steel fiber mix. Huge steel bolts were installed, spaced one meter apart, to keep the structure from collapsing. Built at a cost of $715 million, the facility is designed to hold about 8 million barrels of oil. When complete, the five caverns here will free up 84 football fields’ worth of land that can be used for higher-value petrochemical manufacturing.

The caverns are just one of many projects that has Singapore looking underground as its next frontier for urban growth. Around the time the Caverns project began, Singapore opened an underground ammunition storage facility for the armed forces. That freed up more than 700 acres (280 hectares) of land for surface-level development.

Today, Singapore is digging the Deep Tunnel Sewerage System, a cross-island superhighway of massive conduits for bringing used water to the city’s three water reclamation plants. Singapore recently passed new laws to make underground development easier. Meanwhile, guidelines for underground development are being devised—essentially an urban plan for the land underneath the city.

“Land scarcity has forced Singapore’s planners and politicians to think spatially, three-dimensionally,” says Joshua Comaroff, co-founder of local firm Lekker Architecture, who adds that he admires the “intricacy and imagination” of Singapore’s emerging underground policy. “Land may be scarce, but space is not.”

‘Almost unlimited potential’

Singapore is both a city and a country, located on islands with less than half the land area of London. While that makes some aspects of Singapore’s subterranean approach unique, the thinking behind it is relevant in any dense urban metropolis where prime land is scarce and there’s no room to sprawl.

Indeed, massive underground projects are going on today in cities around the world. Over the next two years, Beijing is adding 40 miles (64 kilometers) of subway lines to a system that already built 235 miles (378 kilometers) from 2007 to 2014. Helsinki recently opened a centralized wastewater treatment plant in an underground location, with a residential development set to be built on the ground above it. New York is finishing up a massive water tunnel that has been under construction since the 1970s. And Amsterdam is excavating an underground location for parking up to 7,000 bicycles.

Alex Marshall wrote a book about the underground of cities called Beneath the Metropolis: The Secret Lives of Cities. “When land prices are very high and there’s not a lot of room to grow, that’s usually when you see cities developing subways or more extensive basements,” Marshall says. “When you can’t go up that much more and you can’t go out, you go down.”

Singapore’s Deep Tunnel Sewerage System is a cross-island superhighway of massive conduits for bringing used water to the city’s three water reclamation plants. (PUB)

Historically, Singapore has looked to build both upward, with taller buildings, and outward, by reclaiming land from the sea. Since its founding in 1819 by the British, Singapore’s land size has grown by about 20 percent. As its population doubled over the past 25 years to 5.5 million, the city sprouted an impressive skyline of tall residential and commercial buildings.

Some of Singapore’s urban action is already underground. Many of the city’s office buildings and shopping malls extend several stories below ground level with shops, food outlets, parking, and walkways connecting buildings.

But in 2013, National Development Minister Khaw Boon Wan said in a blog post that Singapore could do much more with its underground spaces. As inspiration, he cited examples of the “underground city” of tunnels connecting much of central Montreal and the underground siting of swimming complexes, utility plants, concert halls, and churches in Scandinavia.

State developer JTC Corporation has explored the possibility of building an underground science park for 4,200 workers, among other subterranean building projects. This week, JTC issued a call for studying the feasibility of creating an underground network of tunnels for transporting goods between industrial centers and the container port. Such a system could rely on conveyor belts or self-driving cars, and would take numerous trucks off the roads.

In a recent interview with Channel NewsAsia, Lim Eng Hwee, the chief planner and deputy chief officer of the Urban Redevelopment Authority, Singapore’s planning agency, said that building underground presents “almost unlimited potential” for freeing up surface land for other uses.

There may be other reasons to pursue the strategy now, says Andres Sevtsuk, who heads the City Form Lab at the Singapore University of Technology & Design.  

“Its not just because they need space for people, but it also keeps the economy running," Sevtsuk says. Indeed, the income from land sales—$13.7 billion in 2013 alone—helps the government build its cash reserves. Sevtsuk adds that Singapore’s rush to develop land beneath the surface might also be coming from the realization that the cheap labor required for such projects is only going to get more expensive over time.

New legal and planning frameworks

In March 2015, Singapore’s parliament amended two laws to facilitate underground development. One bill changed the State Lands Act to say that by definition, the state owns underground space more than 30 meters below the surface. The other amended the Land Acquisition Act to give the state the right to buy out plots of surface land or a specific stratum of subsurface space so that the ground underneath it can be accessed.

Meanwhile, consultants have been hired by the Urban Redevelopment Authority to work on a set of guidelines for the development of subsurface space. This would help government agencies shape future land-use decisions and earmark sites for development.

In a 2014 tender for the consulting work, the authority said it is seeking to "develop a comprehensive and holistic framework to enable more extensive use of underground space in Singapore” and that the guidelines would be a step towards the creation of an underground master plan. The government has not disclosed anything publicly about the plan other than the fact that it is in the works. The Urban Redevelopment Authority declined to provide comments to Citiscope, saying that it is not ready to release any further details to the public at the moment.

Petrochemical plants on Jurong Island account for one-third of Singapore’s manufacturing output. Putting some of the industry’s storage needs underground has freed up land for higher-value manufacturing. (Flickr/Kunal Mukherjee)

One likely goal of the guidelines is to serve as a precautionary measure to ensure that the government has control over how private developers dig. Another is to regulate what is likely to become a growing number of public-private partnerships in carrying out underground projects.

"Based on what we know, it’s forward-looking and innovative to do this,” Sevtsuk says. “But there are a lot of important social and economic hazards to look out for.”

One of those hazards is cost. Developing underground typically costs about 10 times more than on the surface.

As with urban planning above ground, there are also issues of access and public interest. In a city that is sometimes criticized for having too many shopping malls and banks, the question is whether developing underground space will actually help achieve a more balanced mix of uses for all people. Singapore has a great need for more public spaces and lower-end commerce that serves the interests of the middle and lower-middle classes.

The idea of actively developing Singapore’s underground space has its critics. One of them is Liu Thai Ker, Singapore’s former chief planner. He thinks city dwellers would chafe at spending significant portions of their lives in underground settings.

“The big push for underground space is a cop-out,” says Liu, who is now chairman of the Centre for Liveable Cities and director of RSP Architects, Planners & Engineers. “Even if there are people willing to work or live underground, it incurs a greater cost to develop. And it would take forever to ventilate and cool the space, so it is totally un-green.

“If you are short of land,” Liu continues, “the solution is to find a better way to create a liveable environment above ground, at a higher density. In my book, going underground is not innovation.”

Sevtsuk agrees that Singapore has more room to grow upward before it needs to grow downward. “Singapore has plenty of space,” he says. “Its density is far below that of Hong Kong or any other very dense city. In fact, it is less dense than most European city centers."

Comaroff, however, thinks that Singapore’s underground visions should not be dismissed so quickly. He points out that Singapore’s urban planners have a good track record when it comes to executing big ideas, and sees their successes with high-rise public housing as a reason to be optimistic.

“Modernist social housing has failed nearly everywhere else; in Singapore, it has been a resounding success due to the careful management of housing by the government and the adaptability of the public to new ways of living,” Comaroff says.

“We are probably wise to be aware of the concerns about this new venture, but I wouldn't condemn it to the world of fantasy just yet.”

This story originally appeared on Citiscope, an Atlantic partner site.

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