Explainer:Do we really need Giant Seawalls? —-Revision after three years from 2011 Tsunami

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Three years have passed since the 2011 Earthquake and Tsunami which killed more than 18,000 residents of Tohoku region in northern Japan.
On a day before the memorial day for this big disaster, Japanese Prime Minister Abe made announcement at the Budget Committee of the Upper House of the Diet in Japan that he is positive about revision of the government led plan to construct giant seawalls along the coast line of the area, and will respect the intention of the local governments.

You might wonder why the government is not constructing the giant seawalls to save the lives of people in a hurry.
But stop and think. Would giant seawall, massive monolith of concrete solve everything? Let’s see what was planned, what happened to the seawalls on March 11th, and what people think now.

What is seawall
A seawall is a form of coastal defense constructed to protect inhabited areas .
At least 43 percent of Japan’s 18,594miles (29,751 km ) coastline is lined with concrete seawalls or other structures designed to protect the country against high waves, typhoons or even tsunamis. The average height of seawall is between 14.7feet to 25.6feet above the low water level.

What happened to the seawalls in Tohoku region –some survived and some not
Tohoku region has experienced 3 big Tsunamis during last 100 years, including the one in 2011. One of them came all the way from Chilean Coast (1960 Valdivia earthquake) and killed 147 people in Japan.
So they knew the importance of seawall.

There were two significant seawalls.
Fudai Village in Iwate Prefecture experienced Tsunami caused by 1896 Sanriku earthquake. The height of Tsunami was 50 feet high and killed (including missing) 1,010 villagers. In 1933, another Tsunami hit the village and took the life of six hundred people. After WW2, a village mayor insisted on construction of big seawall which is high enough to protect the village from Tsunami as high as the one in 1896. A giant seawall and lock gate was constructed spending 36 million dollar.

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(Above:Left side area is the Fudai port hit by Tsunami. The village behind the wall was not damaged)
In 2011, 50 feet Tsunami hit the village. The fishing port and surrounding buildings which were out side of the seawalls were completely devastated. Tsunami was about 3 feet higher than the wall and water came into the village. But no houses nor lives within the wall was damaged.

Fudai village’s case was a lucky one. In 2011, 80% of seawalls in the area were damaged.
In Kamaishi City in Miyagi Prefecture, they had super giant seawalls. They were meant to protect both city and port and constructed at the bay entrance part. It’s seawalls were about 18 feet above sea level and its underwater parts were 200 feet depth. They costed 1.2 billion dollar and took 30 years to build. It was recorded in Guiness Book as “Super Seawall”. On March 11 of 2011, these giant walls seemed to stand fast against pushing power of Tsunami but could not resist its pulling power. Eventually 80% of the walls were broken and allowed Tsunami to hit the city center.

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(Above Top: Super Seawalls at the mouth of Kamaishi bay /Above next: Seawall tore into pieces by Tsunami)
Government led project with huge budget
After the Earthquake of 2011, Jqpanese government together with 3 local governments of Tohoku region proposed Disaster Restoration Projects to build giant seawalls of 50 feet high, which are as high as 4-storied building. The total extention of seawalls would be  188 mile and the initial cost would be 10 billion dollar.
It seemed to be welcomed by people at the beginning. But as time passed by, people started to ask if they want to live near a huge wall where you cannot even see the color of the sea. No one can tell that the next Tsunami will never exceed 50 feet.
The towns near the coast line started to rebuild community on the hill, which left the areas on the shore deserted. Do we need expensive seawall to protect the place where no one lives
Two big industries in Tohoku area are fishing and sightseeing. People in the city of Kesennuma started to ask themselves “Would people come to visit the city surrounded by huge seawalls, where all you can see is huge mass of concrete?”

The Risk of Dependence on Seawalls.

It is pointed out that such hardened coastlines can also provide a false sense of security to property owners and local residents as evident in this situation.  People  narrowly missed being hit by Tsunami said, “I thought my house was safe because we had seawalls.”  Many volunteer firefighters rushed to the coast line to close the lock gate and lost their lives.

Kiyotaka Abe, 90 year old retired teacher, survived three Tsunami in his life time.”Just run up the hill as high as you can. Do not trust the words, << It only came as high as this level in the past.>>.Unexpected things do happen.”

For Whom the Wall will be built
Then media reported that there is a plan to build giant seawalls even around the uninhabited island. Municipal office of Shiogama City explained that they are meant to protect rice paddies on the island, which are not cultivated more than 10 years.

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Why such a meaningless plan can easily presented.
Procedure for Disaster Restoration Projects is different from usual public undertaking.
In case of public undertaking, the verification of the cost-effectiveness,environmental assessment and  some time for consensus building with local residents are required. Disaster Restoration Projects are not required to do all these things thoroughly.

Who pays for the giant seawalls?
Most of the cost for the Projects is covered by budget for reconstruction. Japanese government raised corporation tax, income tax,and residents’ tax to cover the budget.It seems only the construction plan for giant seawalls was moving fast and talked in a loud voice. One cannot but speculate that it is because it brings huge money to the construction industry
The future image of the community in Tohoku area is not clear. There are voices that the younger generation should participate more for the reconstruction of the areas. Because they are the people who will manage the future and keep paying tax for them.

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The movements among the citizen started to understand the meaning of giant seawalls and to talk about what kind of community they want in the future.The voices of young generation are gathered.High School student, Naoko Matsuda looks back the experience of Tsunami and said .”Our sea betrayed us by destroying our town. But I also have all my good memories  with sea.I cannot hate it.The adults are arguing about the height of the wall.But height is not the matter. I think most important thing is that we all should know that you have to protect your own life by yourself”.

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