Japan’s 400 Kilometre Tsunami Shield

Meet one of the most important pieces of concrete in Japan.

Executive Producer and Narrator - Fred Mills
Producer - Jaden Urbi
Video Editing and Graphics - James Durkin
Production Management - Clare Furlonger
Content Partnership - Liam Marsh

Special thanks to Dr. David McGovern and Damien Lutz. Additional footage and images courtesy of Channel 4, ABC News, CNN, Rs1421, Hitoshi Taguchi, International Journal of Disaster Risk Reduction, HR Wallingford and UCL/URBANWAVES, Electric Entertainment and Morino Project.

#construction #architecture #engineering

Ripping and/or editing this video is illegal and will result in legal action.

© 2021 The B1M Limited

[waedidmyhandlechange]

Can't believe that it's been 10 years since the tsunami. It feels like those 10 years just flew by.

[hhydar]

I actually like the idea of building forest walls along the coastline. One force of nature can be efficiently tackled with another form of nature. Even mangroves are a brilliant solution but i dnt knw if they are fit for Japan's climate.

[AbroadinJapan]

This was a very well researched video!
As someone lucky to live on Japan's east coast, I've traversed almost the entire length of the tsunami shield over the years. The locals seem to have mixed feelings on them, many sacrificing sea views for safety. The government didn't give many towns and villages much choice in the mater unfortunately and in my view, they've gone too far and built too many. Just last week I drove passed a beautiful beach that had no houses or villagers nearby, but the entire area has been smothered in concrete. Still, for the most part the reconstruction in Fukushima, Miyagi and Iwate has been impressive and many locals are optimistic for the future, despite the nightmare they endured.

[HokkaidoHiguma-jj]

I live in Japan and was driving along the Sanriku coast last week. It really is remarkable how far Japan has come in 10 years.

[lucianolizana]

In Chile, after the 2010 earthquake and tsunami, the aproach in the city of Constitución was to build large forest areas in the coasts to laminate the water (and also create new green areas)

[garrettk]

The 2011 Tsunami hits me hard, emotionally, every time I hear about it. I was on Maui during that, and we were terrified that we'd get hit by the tsunami. Thankfully we didn't. My heart goes out to Japan.

[TheBritalianJob]

I wonder if they could make a feature out of the walls - creating a raised embankment on the land side so that the view can be enjoyed again, mainly as public parkland or as private enterprise leisure districts. I’d imagine that amount of earth against the walls would also help reinforce them

[SimplyCivil]

I really enjoyed reading through the innovative and creative solutions mooted in the comments. It's great to see such discussion stimulated on big engineering projects. A couple of broad themes I noticed we're 1) build a concave/wave return wall and 2) the issue of sea level rise. 3) the use of trees etc.

With 1), concave walls with wave return crowns and similar are designed to reflect wind wave energy back seaward. The reason this wouldn't work in a tsunami is that a tsunami is a very very long wave (km in length) in comparison to a wind wave (10s of metres in length). Thus the wave energy is spread out over a huge length. This is why the wave takes 10/20 minutes to inundate before the water begins to recede. It is analogous to a open channel flow like a river in a continuously rising flood condition. So wave energy reflection, which can also rely on the wave breaking to some extent, is not applicable here.

2) sea level rise. The point is that the current infrastructure is built on a known mean sea level. Once we start getting the SLR effects then such infrastructure might not be able to perform its function as well. Here, a 15 m tsunami wall may then be only 14.5 or 14 m in the future.

This strikes at the core of the debate: do we build hard sea defences in a 'hold the line' approach or do we retreat from the shore line completely, or do we use natural defences or a combination thereof.

3)On mangroves and forests. It's proven for hurricanes/typhoons and storm surges that these can help a lot. But it's less clear on tsunami. Again because of its open channel flow like behaviour. The tohoku tsunami of 2011 resulted in a lot of said trees becoming floating missiles. Some of our experiments also showed that the flow constriction effect (reducing the flow area by adding obstacles) can result in higher flow velocities through the remainder of the area.

There's much work to be done in this area still.

[economicsinaction]

Just get 🇳🇱 Dutch and 🇯🇵Japanese engineers around a table and sea flooding problems are no more!

[adarshpandey]

Japan always has something incredible. The more I see, more I learn.

[willcragg]

I just finished watching the video about the wooden skyscrapers. I just love the B1M, they always have great video

[door-to-doorhentaisalesman]

They should make three 50 meter tall walls and call it: Wall Maria, Wall Rose and Wall Sina.

[TinaMcCall.]

"Be like water" is a martial arts tenet for good reason. No matter its state, it will find a way to create and destroy.

[thuydao]

Regardless of what they did in the past. Modern Japan is a great aspiration for the world to look up to.

[RussellChapman]

Fukushima almost failed safe. But for the location of the back-up generators and heat-exchangers, there would not have been a meltdown. The plant survived the M9 earthquake, but it was the size of the tsunami, (nobody imagined it could be that big), which overcame the back-up systems. Nuclear power is pretty safe, built on modern systems, away from seismic areas, it is highly unlikely a Fukushima MK2 would happen again. The tsunami killed way more people, over 20000, than the meltdown, less than 600.

[djp]

I still can't believe they put the Fukushima emergency generators on the ground floor and not on the roof. How did they not see this coming?

[yashrajsomvanshi]

Japan is just one incredible country!🤩

[gregparrott]

One item not mentioned here is that not only was the tsunami taller than the wall, but that the subduction caused by the fault's slippage LOWERED THE WALL ITSELF by about 2 feet.

[MT-zsrd]

Hey the channel reached 2 million subs, let's go!

[asdsdjfasdjxajiosdqw]

It might be a different scale to the construction this channel normally features, but could you do a video on bicycle highways in Europe? Or just cycling infra in general?