Singapore Looks Below for More Room

SINGAPORE — Singapore, with a little less land mass than New York City, is running out of room for its 5.4 million people.

The city-state has built upward — with apartment buildings reaching as high as 70 stories — reclaimed underused properties for housing and pushed out coastlines for more usable land.

But as one of the world’s most crowded cities, and with projections for 1.5 million more people in the next 15 years, Singapore’s options are as limited as its space.

So Singapore is considering a novel solution: building underground to create an extensive, interconnected city, with shopping malls, transportation hubs, public spaces, pedestrian links and even cycling lanes.

“Singapore is small, and whether we have 6.9 million or not, there is always a need to find new land space,” said Zhao Zhiye, the interim director of the Nanyang Center for Underground Space at Nanyang Technological University. “The utilization of underground space is one option for Singapore.”

Height restrictions imposed on areas around air bases and airports have prevented developers from building taller projects. And there is a limit to how much land can be reclaimed from the ocean — so far it accounts for a fifth of Singapore’s space but it is vulnerable to rising sea levels caused by climate change.

The squeeze has led to the closing of several old estates and military camps to make way for residential and industrial developments.

Building underground is not new in Singapore. About 12 kilometers, or eight miles, of expressways and about 80 kilometers of transit lines are below ground. Drainage systems and utility tunnels are common features beneath the urban landscape.

Now Singapore is going further, beginning work on a huge underground oil bunker called Jurong Rock Caverns. When this is completed, it will free about 150 acres of land, an area equivalent to six petrochemical plants.

Another project on the drawing board is the Underground Science City, with 40 interconnected caverns for data centers and research and development labs that would support the biomedical and life sciences industries. The science center, with an estimated 50 acres to be 30 stories below a science park in western Singapore, would house as many as 4,200 scientists and researchers.

“A lot of facilities can go underground if you fully utilize the underground space,” Dr. Zhao said. “In the beginning there might be a psychological issue, but as long as we have proper lighting and proper ventilation, gradually people can overcome the idea of working and living underground.”

Subterranean projects can be three to four times as costly as surface projects because of higher construction costs and the need for extensive soil investigations.

In a recent blog post, Khaw Boon Wan, Singapore’s minister for national development, pointed to extensive pedestrian passageways and shopping malls in Japan and Canada.

He cited the possibilities in Singapore “of creating underground transport hubs, pedestrian links, cycling lanes, utility plants, storage and research facilities, industrial uses, shopping areas and other public spaces here.”

“The earlier we begin this process, the faster we will learn and the easier it would be for us to realize these plans,” he said.

But the idea of working and living underground has met with some skepticism from the public.

“Over the years, many of us have relocated from kampongs to high-rise living in government flats,” said Joseph Tan, 69, a retired accountant, referring to traditional Malay villages. “Just when we have finally adjusted to living in these residential buildings, there are plans for us to live below ground. At my age, I just hope to live comfortably.”

David Ong, a former teacher, said the older generation might not feel at ease with the concept of subterranean living, partly out of superstition.

“Why are the living going underground?” he asked. “Only the dead return to the ground.”

The trend toward burying infrastructure has led city planners to think grandly, as they consider whether more activities could occur below ground. Some projects, like the excavation of underground tunnels and Jurong Rock Caverns, are already in full swing.

At the city’s two oldest universities, Nanyang and the National University of Singapore, studies have identified suitable areas to build sports facilities, libraries and lecture theaters below ground. According to researchers from both institutions, students may one day swim in an underground pool or watch a film in a subterranean theater.

But even with the current projects, subterranean development in Singapore is still in its early stages.

Dr. Zhao, one of the researchers behind Nanyang’s study on underground development, said extensive studies were needed.

“It is a big investment if we really want to go underground, and it requires comprehensive studies and careful planning,” he added. “At the moment we manage fine, but if there is a need for space in future, we know that there is the option of going underground.”

Singapore Looks Below for More Room