Japan Tsunami: By Rebuilding After Disasters, Is Japan Putting Its Coast At Risk Again?

In the wake of the devastating tsunami that hit Japan in 2011 following a magnitude-9.0 earthquake off the coast, the Japanese government is moving to recreate the concrete coastline that previously existed. Regional and national authorities are planning to build, and in some places have already built, massive seawalls and other coastal defenses with the goal of protecting the communities living along the coastline. Environmentalists, however, have criticized the strategy, saying that authorities have ignored a chance to rethink how communities live along the coast and that the seawall structures will damage coastal ecosystems.

The debate highlights the issue of protecting the environment given the pressures of a massive population and limited land, and the tendency for environmental considerations to be overridden by other concerns. It also shows how, as with the earthquakes in Christchurch, New Zealand, disasters can provide an opportunity to rethink how we live, an opportunity that should be made the most of. 

Journalist Winifred Bird writes that following the tsunami, which claimed over 15,000 lives and wrought extensive destruction along the northeastern coast of Japan, "scholars, activists, and fishermen alike saw a chance to rethink how people live on the coast." Instead authorities are moving to recreate things as they were, rebuilding previously existing seawalls and coastal defenses and even making them bigger: "Reconstruction plans in heavily damaged Iwate, Miyagi, and Fukushima prefectures call for a string of 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."

Image credit: Winifred Bird

Yoshihiko Hirabuki, a plant ecologist at Tohoku Gakuin University in Sendai, Miyagi Prefecture, has criticized the plans, saying, "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." According to Hirabuki, not only is a chance to begin repairing previous environmental damage along the coastline being missed, but many of the new constructions will be bigger and more invasive than previous seawalls. 

According to Japan's Ministry of Environment, over 56% of the coastline on Japan's main island, Honshu, is now partially or fully artificial. And this figure is only set to rise further with the new plans. Bird argues: "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."

While environmental-impact assessment laws in Japan currently do not apply to the type of construction that is happening on the coastline (seawalls, disaster prevention forests, and two-lane roads), the fact that the issue of the environmental impacts of coastal land use is even being discussed is promising. Satoquo Seino, a professor of environmental engineering at Kyushu University, notes that this is the first time that it has been debated on a national level.

Image credit: Winifred Bird

The obvious question is, If not seawalls and the other sorts of coastal defenses that are being constructed, then what? Hirabuki and Seino say that there are alternative solutions. Hirabuki is pushing the authorities to forgo the earthen banks in some places, or to better integrate them into the existing environment, while Seino argues that the seawalls should be shorter and narrower, and built further inland where they will not disrupt coastal ecosystems. Mitigating the effects of the construction is one thing, but Seino and Ryuichi Yokoyama, director of the Nature Conservation Society of Japan, say that the best solution would be to resettle people on higher ground, maintaining a buffer zone along the coast. Indeed there are hundreds of so-called tsunami stones, some over 600 years old, along the coast in Japan warning locals not to build past certain points. And while many forgot or ignored these warnings, some places, such as the village of Aneyoshi, did not, and residents say it meant their village avoided being destroyed in the tsunami.

The issue of the environmental impact of coastal defenses and alternative solutions is obviously a complex one, especially given Japan's massive population and small size, as well as its desire to do something immediate and tangible to protect coastal communities. But discussion of environmental impact and alternative solutions is definitely a conversation worth having. The problem is that as it is happening, construction is already taking place, further expanding Japan's concrete coastline.