The Giant Underground Tunnels Protecting Tokyo From Floods

The Giant Underground Tunnels Protecting Tokyo From Floods


The city of Tokyo is built
around and over rivers. When you travel around here, it is striking
just how often you cross water. And from up above, you can see this
whole area is flat, low-lying coastal land. Some parts of Tokyo even sit below sea level. They’ve sunk because of decades of
pumping out groundwater. The two and a half million people
in those low-lying areas are protected by a network of
flood gates and aging levees, which’ll be fine unless sea levels rise. But even inland, a huge part of this megacity is built
in river basins and flood plains. And as the climate breaks down, rain storms here are getting more intense
and more frequent. If you want to prevent river flooding, or drain neighbourhoods
that are starting to flood: where do you put the water? If you pump it out of that neighbourhood, you’re likely just moving the flood next door. The best plan would, in theory, be to pump the floodwater
all the way to the ocean, or at least to a tidal river
that can deal with it. But for that, you would need tunnels and
buffer tanks on an almost unimaginable scale. Now, despite what some
breathless blog posts might claim, the whole metropolis doesn’t have that. But there is one place, about an hour
north of the centre of Tokyo, that does. This is the Metropolitan Area
Outer Underground Discharge Channel, or at least, one part of it: the holding tank. It is almost impossible to convey the scale
of this on camera. [IN JAPANESE:] If the Otoshifurutone and Naka rivers
start to flood, this is where the water will drain to. Actually, where the water
is sort-of still draining to. There was a massive rainstorm about two days ago, and there is still water in the system. I am not allowed down on the floor,
just in case. [IN JAPANESE:] This tank, and the kilometres of tunnels and
all the silos that bring water to it, cost nearly a quarter of a trillion yen, that’s about two billion US dollars,
at the end of the 20th century. That was when the Japanese government was
spending money to finance enormous
infrastructure projects like this, to try and stimulate the economy. Which, for long-term security, is great: but it took a national recession
to make this happen. A plan like this only works if a government
wants to spend a colossal amount of money, and in the 21st century, there aren’t many governments
willing to do that. Thank you to all the team here
for letting me down in the tank, and up on these catwalks.
You can find out more about them and their work
at the link in the description. Echo! [echoes continue and fade] That goes for a long time.

100 Replies to “The Giant Underground Tunnels Protecting Tokyo From Floods”

  1. Maybe you should double-check: 120 and 70 hectares are very less I can not imagine why to invest so much for such a small advantage.

  2. Bihar and Assam States in India can use such system. Tax money should go to such projects instead of subsidies that make economy inefficient.

  3. They can lie all they like its clearly an ancient alien machine for producing oxygen, just like the one on Mars

  4. Drainage systems fascinate me a lot, because they take up so much land and you see them everywhere, from the ditches going along the side of the road to the mysterious pits full of pipes and grates, and yet I know so very little about them. It's great to hear more about one of the systems.

  5. Ground below sea level because they pumped too much ground water out but had to throw in a buzzword. Glad someone else did this exact video with a translator.

  6. Wow, I knew the tunnels were massive, but I thought they handled the entire city. Wow. Just a little sliver of Tokyo has the tunnels!

  7. I'm seeing this area like a boss video game boss arena. Fighting a water boss in a storm drain like this would be awesome. You have to run around to climb on to walkways which the boss destroys quickly so it can't get you. The way to defeat the boss after weakening it by shooting at it from the walkways would be to destroy the supports until the room collapses and crushes it. I'd love to see a game do something like that.

  8. "These tunnels can prevent flooding for most of the region"

    Climate Change: Allow me to introduce myself…

  9. "A typhoon struck this area in year 2000 before this facility was constructed"
    So they built it in under 20 years time, miracle of engineering right there, IN MY COUNTRY IT'S TAKING FREAKING 30yr TO BUILD ONE HIGHWAY AND IT'S STILL NOT DONE YET!!!!!!!

  10. This is where Netero vs Meruem took place. Underground Tunnels, the atomic bomb, Japan, it all checks out.

  11. Oh no, there are many govts willing to spend yewg amounts of money, just not on useful things or in efficient ways.

  12. "A Number of small and medium sized rivers flow into this district of Tokyo and they used to flood a wide area … " now they don't , says it all ..

    Given the money anything is possible … and often not advertised …

  13. You are British, right? You know Europe has the land of Netherlands, 2/3 of which is actually under the sea level. Why The Heck should I care about a far eastern state?

  14. USA spends 4 billion dollars a month in Afghanistan on a pointless war , compare that to the Japanese building water tanks to improve their country, how come the USA cant give the American civillians free health care ?

  15. you know what tom…ive only recently got on your videos on i must say they are very informative and interesting…. some really unusual facts in there …… good job buddy

  16. -Land has sunk from pumping ground water
    -Storms are now more intense since land is below sea level
    IT HAS TO BE CLIMATE CHANGE!!!

  17. Location coordinates at each cutscene:

    00:00 = 35.6698, 139.7828 (looking NNE)
    00:03 = 35.6949, 139.7880 (NE)
    00:05 = 35.6961, 139.7852 (SSE)
    00:07 =
    00:09 = 35.6844, 139.8645 (WNW)
    00:14 = 35.6698, 139.7828 (NNE)
    00:22 = 35.6730, 139.7815 (S)
    00:24 =
    00:26 = 35.6698, 139.7828 (NNE)
    00:39 =
    00:44 = 35.6698, 139.7828 (NNE)
    01:12 = 35.9972, 139.8123 (W)

    01:15 = 35.9955, 139.8105 (NE)
    The rest are all underground at the last timestamp. I have no idea why I spent time doing this.

  18. tom, could you please make a video on how you get access to all of these random things? how do you get permission to get in these tunnels for example?
    just an idea for a video.

  19. 3:15 “thank you to all the team for letting me down”

    replace “all the team” with “life” and you have the story of my life

  20. Not a bad idea! I wonder if something like that could be constructed in Arkansas to protect the farmland from flooding?? We had a flood like i've never experienced earlier this year. Took out a BUNCH of crops and at least 1 hog farm.

  21. Japan, where the whole country is willing to take a recession for 137 hectares of land and its inhabitants. Be more like Japan.

  22. "there arent many governments willing to do that"

    yup and thats why in the uk we have a housing crisis and the government is building more luxury housing than council housing

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