16 May 2013: Report

In Post-Tsunami Japan, A Push
To Rebuild Coast in Concrete

In the wake of the 2011 tsunami, the Japanese government is forgoing an opportunity to sustainably protect its coastline and is instead building towering concrete seawalls and other defenses that environmentalists say will inflict serious damage on coastal ecosystems.

by winifred bird

In the years leading up to the massive tsunami of March 11, 2011, it seemed that Japan’s coastal ecosystems could hardly decline in health any further. Decades of coastal engineering had divided land from ocean, turned quaint seaside towns grey with concrete, and pushed once-familiar species like loggerhead sea turtles and common orient clams towards extinction. Nearly half of the island nation’s perimeter was modified in some way; cliffs comprised most of what remained untouched. Even within the government, a sense had begun to spread that in a country where the sea has shaped culture and cuisine for millennia, coastal land management had taken a wrong turn.

Then came the once-in-a-thousand-year tsunami. Walls of water swept over the coast of northeastern Japan, claiming more than 15,000 lives and destroying hundreds of thousands of buildings, together with 60 percent of seawalls. In the rubble-covered wasteland that remained, scholars, activists, and fishermen alike saw a chance to rethink how people live on the coast.

Instead, national and regional government bodies are moving to recreate the concrete coastline that existed before. Reconstruction plans in heavily damaged Iwate, Miyagi, and Fukushima prefectures call for a string of
The government has let slip a rare chance to heal past harm by implementing more sustainable strategies.
stunningly tall and wide seawalls. Some have already been built; many others are in the final stages of planning. A second layer of raised earthen banks topped with pine trees is also planned in many places. And with Shinzo Abe’s Liberal Democratic administration promising a major infusion of funding for disaster prevention projects nationwide, new seawalls are in the works well beyond northeastern Japan.

The goal is to protect human communities along the coast. But ecologists, environmentalists, and some coastal residents say the plans are an environmental calamity.

“We’re facing the possibility that it’s not the tsunami but rather the reconstruction work that will wipe out the extremely important natural ecosystems along the coast,” said Yoshihiko Hirabuki, a plant ecologist at Tohoku Gakuin University in Sendai, Miyagi Prefecture. In part, the problem is that many of the new seawalls will be taller, wider, and possibly longer than they were before the tsunami, endangering seaside ecosystems that managed to survive earlier decades of coastal engineering. But Hirabuki and others are also frustrated that the government has let slip a rare chance to start healing past harm by implementing new, more sustainable coastal management strategies.

Hirabuki is one of many scientists who surveyed tidal flats, wetlands, beaches, and bays in northeastern Japan following the tsunami and concluded that, despite severe damage at some sites, wild plants and animals are making a strong recovery. He says plant communities on Sendai’s coast have bounced back “beyond all expectations,” and describes some sections of the beach as a flower garden of native plants humming with local bee species. The tsunami created new habitats, as well: In a 2011-2012 survey of the disaster zone, the Nature Conservation Society of Japan identified twenty new marshes.

View gallery
Seawall Miyagi Prefecture Japan

Miyagi Prefecture
An illustration of a seawall planned in Miyagi Prefecture, one of the areas most affected by the 2011 tsunami.
The reconstruction is threatening that natural recovery in a number of ways. Depending on their design and location, seawalls — some of which are 45 feet tall and more than 150 feet wide — can block the movement of water, sand, and living organisms between land and sea. They can physically obliterate tidal flats, dunes, and other important habitats — as can coastal roads and earthen embankments. The construction work required to build these structures can also severely disturb natural habitats.

The central government’s environmental impact assessment laws do not apply to seawalls, disaster prevention forests, and two-lane roads like those being built and planned on the coast. However, Miyagi and Iwate Prefectures have set up committees to discuss the potential environmental impact of the work.

”As we carry out the construction work we are taking each ecosystem into consideration and receiving advice from experts,” Masayuki Kadowaki, who oversees seawall planning as director of the rivers division of Miyagi’s Public Works Department, said in an email.

Critics counter that these measures will bring little real change.

“What we are at great risk of losing is the seashore itself,” says Ryuichi Yokoyama, director of the Nature Conservation Society of Japan, which is
‘What we are at great risk of is losing the seashore itself,’ says one scientist.
campaigning against the current reconstruction plans. Northeastern Japan’s coastal ecosystems are difficult to protect, he says, because they are both narrow and congruent with the planned sites of coastal engineering projects: “You have a zone that’s maybe a fifth of a mile wide,” said Yokoyama. “You build a seawall and a road and your fifth of a mile is gone.”

Satoquo Seino, a professor of environmental engineering at Kyushu University, says it’s the first time coastal land use has become an issue of national debate.

“[When policy is set] disaster prevention comes first — ecosystems are secondary,” says Seino, who sits on the central government’s specialist advisory group for coastal policy. Government planners are making an effort to listen to recommendations from ecologists. But, said Seino, “Those groups don’t have political power or money. Opinions from the construction industry take priority, so we are not seeing any big changes.”

The roots of the coastal land-use debate go deep. People first began moving from higher elevations down toward Japan’s seashore, which offered rare expanses of flat land, at the beginning of the Edo period (1603-1868), Seino says. “Over a period of 400 years Japanese moved further and further into these dangerous areas, as modernization allowed for more public works projects,” she explains. “[Today], by law, the land management concept is to claim everything down to the high-tide line as human territory.”

Japan Prefectures
Yale Environment 360
In the three most heavily damaged prefectures, plans call for extensive rebuilding and expansion of seawalls.
The percentage of fully or partly artificial coastline has now surpassed 56 percent on Honshu, Japan’s main island, according to the Ministry of Environment. In 1945 the country had about 84,000 hectares of tidal flats; by 2001, reclamation for agriculture, industry, and housing had reduced the figure to less than 50,000 hectares, the government reported. The Ministry of Agriculture, Forestry, and Fisheries says some 55,000 hectares of seagrass beds were lost between 1988 and 2001. Beach erosion has become a serious problem, as well. And with waves now breaking directly on seawalls in many places, less and less beach remains for sea turtles to nest or endangered plants to thrive.

The reconstruction strategy in northeastern Japan calls for expanding the structures that caused these environmental problems. Badly damaged prefectures such as Fukushima, Miyagi, and Iwate all have announced plans to increase the height, width, and, in some cases, the length of seawalls. Prefectural bureaucrats determine the height of these walls according to formulas provided by the central government. The walls promise protection from tsunamis that occur once every few dozen to 100-plus years — not the much rarer mega-tsunamis like that of 2011.

Before the tsunami, Miyagi Prefecture — which has a mile or more of flat land between the mountains and sea in many places — generally had fewer and shorter seawalls than neighboring regions. Some beaches lacked them altogether. In the northeastern district of Kesennuma, activist and oyster farmer Makoto Hatakeyama says tiny inlets like the one where he lives remained in a relatively natural state. “People had a close relationship with the sea,” he says.

Now, Miyagi’s government is planning to greatly increase the height and width of many seawalls. In Hatakeyama’s hamlet, the prefecture proposed a wall 32 feet high — to the utter disbelief of Hatakeyama and his fellow fishermen and women.

View gallery
Takao Suzuki

Photo by Winifred Bird
Marine ecologist Takao Suzuki stands alongside plastic covering designed to help crabs climb over a seawall.
Takao Suzuki, a marine ecologist at Sendai’s Tohoku University, says a number of the new walls will fragment or smother tidal flats. That has already happened in one part of famously beautiful Matsushima Bay, north of Sendai.

But plant ecologist Hirabuki is even more concerned about the so-called “disaster prevention forests” that are being planned as a second line of defense behind the concrete. Coastal dwellers traditionally planted these strips of pines to block wind and sand; a total of 140 kilometers of them were wiped out by the tsunami. The Forestry Agency plans to replant them.

In Sendai, the trees will stand on top of 10-foot-high earthen banks. The dirt for the banks is being trucked in from nearby mountains and mounded on top of native plants that survived the tsunami or grew back afterwards, Hirabuki says. The Forestry Agency says the banks are necessary for ensuring tree health where the water table is high. But Hirabuki worries that a vital source of seeds for regenerating more heavily damaged parts of the shoreline is being destroyed.

Solutions do exist. Hirabuki is pushing government planners to forgo raised banks in some places and intersperse pine seedlings with existing plants. Seino recommends building seawalls further inland, where they won’t fragment marshes, dunes, tidal flats, or beaches. (Setback also allows for shorter, narrower walls). The most fundamental solution, of course, is resettlement on higher land. Preserving an undeveloped buffer zone along the coast leaves people safer and nature intact, Seino and the Nature Conservation Society’s Yokoyama point out.

View gallery
Seawall Materials in Miyagi Prefecture Japan

Photo by Winifred Bird
Construction materials for a seawall near the Gamo tidal flats in Miyagi Prefecture.
The pace of the reconstruction has left little time to consider alternative options, however: The bulk of subsidies from the national government have a five-year expiration date. Displaced disaster survivors are also divided over how to rebuild. “What’s hard is that people want to get their old life back, but that comes as a set with building these huge seawalls,” Yokoyama says.

Even when communities decide to move en masse to higher land, problems remain. In oyster farmer Hatakeyama’s fishing hamlet, for instance, the fact that all 30 households decided to relocate did not affect plans for a three-story-tall seawall. It was only after Hatakeyama — whose father is one of Miyagi’s most famous environmental activists — spearheaded a petition campaign that the plans were cancelled.

Seino does see signs of policy change ahead.

“I think [the tsunami brought Japan’s] 400-year pattern of ever-expanding coastal development to an end on an intellectual level,” she said. “But the change isn’t immediate. The extreme irony of the situation is that it probably won’t influence what happens with seawall construction in northeastern Japan in the next three years.”

For the region’s natural environment, the cost of that delay could be high.

POSTED ON 16 May 2013 IN Business & Innovation Climate Oceans Policy & Politics Policy & Politics Urbanization Africa Asia Asia 


Very well researched and balanced article! Next interesting points might be:

- a critic of these plans in context to fishery reconstruction (lifting of harbors, re-allocation of fishing rights in spite of depopulation/post-311-mobility etc.)

- effects of relocation strategies on local socioeconomy

Anyway, I enjoyed your conclusion on an important topic, which basic problem arose already a few months ago.

Thank you!

Posted by Dr. Johannes Wilhelm on 17 May 2013

This gives us a window into what will happen around the world as sea levels rise with global climate change. There is already a push for coast defenses to protect developed areas. In the process we may end up loosing our coastal areas to protect our existing infrastructure. An entire eco system decimated in the effort to combat climate change.

Posted by Jud Lohmeyer on 18 May 2013

Japan's natural environment is in an appalling condition already. There is hardly any landscape which has been spared the onslaught of concrete and steel. And now this? It's almost incomprehensible that a developed country as rich in wealth and in (supposed) up-to-date technology cannot come up with a better solution than these environmentally disastous concrete walls. Japan has a "problem" with nature and will not give up the fight against it until the whole country has been smothered with concrete. It also does not seem to be able to bring nature and technology together in any sucessful or appealing way. Japan may well win its fight against natural disasters, but I'm afraid that when the concrete has set it may well have actually lost a lot more than it has saved.
Posted by mike on 10 Oct 2013

Allianz, a Munich based insurance and financial services company, announced this week that it has purchased two wind farms in France, "Croquettes" and "Longchamp," as well as a wind farm in Lower Saxony, Germany. Allianz bought the French farms from Hamburg based wind turbine manufacturer Nordex, and the German one from Husum, Germany based private developer Windkraft Nord (WKN).
Borse Alviero Martini
Posted by borse alviero martini on 17 Jun 2014

Thank you for this article. I worked on the coastline
between Miyako and Iwaki between 2011 until
recently. This is an excellent essay about the debate
concerning the seawall.

I am very interested in learning more about the
mountain scaling and land elevation projects (on
steroids in the case of Rikuzentakata). What are the
environmental impacts of that?
Posted by Ramona Bajema on 03 Sep 2015

There is a lot written here about protecting the grass and turtles, but I find it interesting that Fudai, with its towering wall, was not mentioned. The locals sure seemed happy that the wall was built and their families saved. The answer should come from the people who live there and derive their livelihood from the sea. Give them all their options, examine the repercussions of the different plans, and let the locals decide whether to rebuild the seawalls or relocate to the hilltops. I don't see them lecturing to the residents in Tokyo about all the cement they laid down to make their city, all the areas built on landfill, or what wildlife was destroyed in the process... It should be decided by those with skin in the game.
Posted by Aimee Cooper on 18 Nov 2015


Comments are moderated and will be reviewed before they are posted to ensure they are on topic, relevant, and not abusive. They may be edited for length and clarity. By filling out this form, you give Yale Environment 360 permission to publish this comment.

Email address 
Please type the text shown in the graphic.

winifred birdABOUT THE AUTHOR
Winifred Bird is a freelance journalist living in Japan. She writes about the environment for the Japan Times, Environmental Health Perspectives, Christian Science Monitor and other publications. In previous articles for Yale Environment 360, she reported on the potential long-term impacts of the post-Fukushima cleanup and the challenge of promoting sustainable seafood in Japan.



In Fukushima, A Bitter Legacy
Of Radiation, Trauma and Fear

Five years after the nuclear power plant meltdown, a journey through the Fukushima evacuation zone reveals some high levels of radiation and an overriding sense of fear. For many, the psychological damage is far more profound than the health effects.

As Fukushima Cleanup Begins,
Long-term Impacts are Weighed

The Japanese government is launching a large-scale cleanup of the fields, forests, and villages contaminated by the Fukushima nuclear disaster. But some experts caution that an overly aggressive remediation program could create a host of other environmental problems.

Radioactivity in the Ocean:
Diluted, But Far from Harmless

With contaminated water from Japan’s crippled Fukushima nuclear complex continuing to pour into the Pacific, scientists are concerned about how that radioactivity might affect marine life. Although the ocean’s capacity to dilute radiation is huge, signs are that nuclear isotopes are already moving up the local food chain.

Tracking the Destructive Power
Of the Pacific Ocean’s Tsunamis

The devastating tsunami in northeastern Japan is only one of many that have battered Japan over the eons. In an interview with Yale Environment 360, tsunami and earthquake expert Lori Dengler describes the historic and paleological record of tsunamis across the Pacific, and what it may mean in the future for Japan and the western United States.

In Japan’s Managed Landscape,
a Struggle to Save the Bears

Although it is a heavily urbanized nation, fully two-thirds of Japan remains woodlands. Yet many of the forests are timber plantations inhospitable to wildlife, especially black bears, which are struggling to survive in one of the most densely populated countries on Earth.


MORE IN Reports

As Chinese Luxury Market Grows,
An Upsurge in Tiger Killings in India

by sharon guynup
Poachers killed more tigers in the forests of India in 2016 than any year in the last 15. The spike is linked to demand for tiger parts in China, where the endangered animal’s bones and skins are regarded as exotic luxury items.

New Look at Rivers Reveals
The Toll of Human Activity

by jim robbins
A recent outbreak of a deadly fish parasite on the Yellowstone River may have seemed unremarkable. But a new wave of research shows the episode was likely linked to the cumulative impact of human activities that essentially weakened the Yellowstone’s "immune system."

On Slopes of Kilimanjaro, Shift
In Climate Hits Coffee Harvest

by daniel grossman
Rising temperatures and changing precipitation are taking a toll on coffee farms worldwide, including the plantations around Mount Kilimanjaro. If the world hopes to sustain its two billion cup-a-day habit, scientists say, new climate-resilient species of coffee must be developed.

Aimed at Refugees, Fences Are
Threatening European Wildlife

by jim o'donnell
A flood of migrants from the Middle East and Africa has prompted governments in the Balkans to erect hundreds of miles of border fences. Scientists say the expanding network of barriers poses a serious threat to wildlife, especially wide-ranging animals such as bears and wolves.

How Tracking Product Sources
May Help Save World’s Forests

by fred pearce
Global businesses are increasingly pledging to obtain key commodities only from sources that do not contribute to deforestation. Now, nonprofit groups are deploying data tools that help hold these companies to their promises by tracing the origins of everything from soy to timber to beef.

How Warming Is Threatening
The Genetic Diversity of Species

by jim robbins
Research on stoneflies in Glacier National Park indicates that global warming is reducing the genetic diversity of some species, compromising their ability to evolve as conditions change. These findings have major implications for how biodiversity will be affected by climate change.

Full Speed Ahead: Shipping
Plans Grow as Arctic Ice Fades

by ed struzik
Russia, China, and other nations are stepping up preparations for the day when large numbers of cargo ships will be traversing a once-icebound Arctic Ocean. But with vessels already plying these waters, experts say the time is now to prepare for the inevitable environmental fallout.

How Forensics Are Boosting
Battle Against Wildlife Trade

by heather millar
From rapid genetic analysis to spectrography, high-tech tools are being used to track down and prosecute perpetrators of the illegal wildlife trade. The new advances in forensics offer promise in stopping the trafficking in endangered species.

African Wetlands Project: A Win
For the Climate and the People?

by winifred bird
In Senegal and other developing countries, multinational companies are investing in programs to restore mangrove forests and other wetlands that sequester carbon. But critics say these initiatives should not focus on global climate goals at the expense of the local people’s livelihoods.

Ghost Forests: How Rising Seas
Are Killing Southern Woodlands

by roger real drouin
A steady increase in sea levels is pushing saltwater into U.S. wetlands, killing trees from Florida as far north as New Jersey. But with sea level projected to rise by as much as six feet this century, the destruction of coastal forests is expected to become a worsening problem worldwide.

e360 digest
Yale Environment 360 is
a publication of the
Yale School of Forestry
& Environmental Studies


Donate to Yale Environment 360
Yale Environment 360 Newsletter



About e360
Submission Guidelines

E360 en Español

Universia partnership
Yale Environment 360 articles are now available in Spanish and Portuguese on Universia, the online educational network.
Visit the site.


e360 Digest
Video Reports


Business & Innovation
Policy & Politics
Pollution & Health
Science & Technology


Antarctica and the Arctic
Central & South America
Middle East
North America

e360 VIDEO

A look at how acidifying oceans could threaten the Dungeness crab, one of the most valuable fisheries on the U.S. West Coast.
Watch the video.


The latest
from Yale
Environment 360
is now available for mobile devices at e360.yale.edu/mobile.


An aerial view of why Europe’s per capita carbon emissions are less than 50 percent of those in the U.S.
View the photos.

e360 VIDEO

An indigenous tribe’s deadly fight to save its ancestral land in the Amazon rainforest from logging.
Learn more.

e360 VIDEO

Food waste
An e360 video series looks at the staggering amount of food wasted in the U.S. – a problem with major human and environmental costs.
Watch the video.

e360 VIDEO

Choco rainforest Cacao
Residents of the Chocó Rainforest in Ecuador are choosing to plant cacao over logging in an effort to slow deforestation.
Watch the video.

e360 VIDEO

Tribal people and ranchers join together to stop a project that would haul coal across their Montana land.
Watch the video.