Island fortresses floated for Tohoku

Revolutionary raised complexes on land would guard, rejuvenate region


Special To The Japan Times

The idea of building raised stadium-size “islands” to accommodate tsunami-ravaged communities might sound like a bad joke, but that’s exactly what one architect is urging devastated towns in Tohoku to consider.

Keiichiro Sako of Sako Architects has formulated a blueprint incorporating groups of such isles that will form entire towns and cities, creating a Utopian world he believes would be strong enough to withstand even the most lethal waves.

Each Tohoku Sky Village, as the man-made communities are dubbed, will be built not in the sea, but on the very land that was engulfed by tsunami last March.

Oval in shape and measuring 200 meters at their widest and 20 meters tall, the islands look like colossal, otherworldly sea creatures that have invaded the countryside.

But Sako says they are a practical solution for low-lying settlements that are more susceptible to tsunami and too far from higher ground for relocation.

Most of the islands will be residential, offering 90,000 sq. meters of usable space over three stories. On the uppermost tier will be between 100 and 500 houses and apartments. Gas stations, parking lots, waste disposal and storage facilities will be on lower floors.

Commercial islands, meanwhile, will accommodate factories and processing facilities for industries, including the fisheries and agriculture sectors.

At the center of each island cluster will be the administrative heart, home to municipal offices, schools, businesses and medical, shopping and leisure centers.

The ambitious plan also features the world’s first indoor marina, designed to protect the local fishing fleet.

The design also incorporates several safety features.

Each island will be bolted deep into the bedrock via a series of vast pillars. The exterior walls will be built from 50-cm thick reinforced concrete, while ground floor utility spaces will be compartmentalized in a radial formation for even stress distribution, similar to the way spokes reinforce a bicycle wheel.

The only entrance will be at the rear, guarded by a reinforced gate that will automatically close when a tsunami warning is sounded. Residents will be able to access upper levels via staircases built into the walls.

Those same walls, meanwhile, will allow tsunami to flow around them, unlike flat surfaces that feel the full force of a wave crashing into them.

The plan is far from being mere pie in the sky, and is currently being considered by the city of Natori in Miyagi Prefecture.

“Whereas before people evacuated to designated shelters, now they will just go back to their homes,” said Sako.

What attracted Natori’s municipal authorities to the plan is its focus on returning residents to their hometowns, Sako said.

“Moving to higher ground, which has been recommended by the government, would mean a huge change for residents in the region, many of whom rely on the sea and land for their livelihood,” he said.

“The aim of the project is to not only preserve communities, but to make them safer to inhabit.”

This also was a major consideration behind another large project by veteran architect Toyo Ito. His design, which the city of Kamaishi in Iwate Prefecture is busy mulling over, employs a modern take on traditional architecture and features apartments that will be terraced into the sides of mountains.

All buildings will be elevated 6 meters above ground and built with reinforced concrete, with wooden strutted facades adding a traditional warm touch.

Whereas Sako’s design is not dependent on coastal defenses for protection against tsunami, Ito seeks to utilize and improve on previous structures built to defend communities against huge waves.

In addition to increasing the height of the port-side seawalls from 4 to 6 meters, Ito also is proposing a land-based line of defense in the form of a landscaped waterfront park that will stand up to 13 meters high.

Lined by cherry trees, the park will form a formidable front to a residential zone of steep-roofed, A-frame communal dwellings built in a traditional “gassho-zukuri” thatched-roof style, each containing 16 residential units.

The mountainside apartment buildings, meanwhile, will hold around 20 units, each affording ocean views. This also will make them suitable for residents working in the fisheries sector, Ito says. “They also will back onto an emergency evacuation walkway built into the mountainside,” he added.

In addition, the buildings will feature evacuation areas on the top floors and communal lounges, a concept Ito already has successfully installed at a temporary housing estate in Sendai.

Minna no Ie (House for All) was designed to allow sheltering residents to gather and communicate.

“From talking with residents, it became apparent that many not only wanted to return to their original communities but that they also wanted to do so en masse,” said Ito, who has been working as a special adviser to Kamaishi’s redevelopment committee since June. “They also wanted places where they could freely get together and chat.”

Experts believe both projects are viable, though paying heed to local needs will be a key factor in determining the success of any redevelopment projects.

“The Tohoku people have a strong sense of identity and place great value on human relationships and coexisting with nature,” said Masayuki Wakui, a professor of architectural design at Tokyo Metropolitan University.

“They are also ultraconservative and anyone who thinks they can turn up with some cutting-edge design and get it accepted is wrong. For local residents, landscape equals ‘mindscape,’ ” Wakui said.

Critics of Sako’s plan point to the complex issue of funding the reconstruction of shattered Tohoku communities.

The cost of each island has been estimated at around ¥20 billion.

While this is certainly high, Sako says it would cost considerably more to move entire communities to higher ground. Meanwhile, budgets for costly seawalls could instead be switched to fund construction of the islands, he added.

The cost of Ito’s structures will be between 70 and 100 times less, but his design will offer significantly fewer residential units and will not incorporate commercial, educational and other public facilities.

To reduce costs, the Tohoku Sky Village would make use of existing infrastructure and recycle debris from the March disasters for use in some design components, for example to fill in landscaped gardens surrounding the islands.

It will also employ an interconnected network of various energy sources — including wind, thermal and hydro — to ensure a continuous electricity supply even after a natural disaster.

Additionally, solar panels will be fitted to the roofs of all buildings, a feature Ito also intends to incorporate.

Economic spinoffs are also anticipated, with both architects predicting their projects will attract tourism and investment.

Wakui believes that the advantage of Sako’s project is its innovative approach to industry. This includes the ability to grow agricultural products indoors using LED lighting — an obvious asset for farms impacted by the Fukushima nuclear disaster — while the need for waterfront fisheries facilities will become redundant.

“The concentration of industry under one roof offers the potential for innovation and the creation of new areas of commerce,” Wakui said.

Ito is also proposing a second area of Kamaishi be developed into rugby facilities that can host games during the 2019 Rugby World Cup that Japan will host.

“The city’s team has a strong reputation in the sport, which is consequently popular among local residents,” said Ito. “In addition to maintaining that cultural link, there would be economic benefits of hosting the competition as well.”