It is limited viewing, requires a reservation & the slots run out practically in seconds. Tough for us residents to get it as well. My wife could snag it in her third try, as a late birthday trip last year.
It is gargantuan & having massive holding capacity. To give semblance with something familiar, it was like standing in NY Grand Central station, except it was felt bigger, empty, damp & illuminated by floodlights from all sides. It is probably one and half football fields in length & scales high as much as a five storied building. Uploaded three pics to show the scale of this megalith. (The base of the pillars here are taller than average height of person to give a rough scale. The stairs come down from the ground level)
https://i.imgur.com/Jtcy0Ct.jpeg https://i.imgur.com/8Q08eKS.jpeg https://i.imgur.com/y75sfGP.jpeg
In addition to this underground chamber, there are two massive pumps on either sides, which divert the water from whichever river is surging to the other (Arakawa & Edogawa possibly). The chamber is the buffer zone between the rivers, not a storage tank ultimately. I was told by the civil engineer of this plant they could pump out as much as a jumbo jet's volume per minute in its storm surge channel/drain to manage flooding. You can walk up to the turbine room at the end of this room, and see its massive blades at an arm length. All with earthquake protection in place as well. Honestly mind-blowing piece of engineering.
Here are a couple photos I took with people for scale:
You probably mean pumping stations right? Usually single pumps don’t have that kind of flow rate. Just a nit pick though, your comment was really interesting!
Those pictures look unreal!
It’s time to go when your guide says: “It’s inexcusable and I’m very sorry for the inconvenience, but the control room has informed me that we should make our way towards the emergency exit five minutes to the south west of the left of the 7-11. Thank you for your understanding and cooperation.”
It is an awesome space and surprisingly well lit.
I guess it’s connected to this one, though I can’t find any information on that reservoir in specific.
https://sushitech-startup.metro.tokyo.lg.jp/sightseeing-tour...
It’s pretty relevant as my house is about 50m from that river.
There was also a good NYT article in 2017 (293 points, 210 comments) https://news.ycombinator.com/item?id=15436943
Tokyo Metropolitan Area Outer Underground Discharge Channel - https://news.ycombinator.com/item?id=43816183 - April 2025 (6 comments)
Tokyo expands underground 'temple' complex to counter climate change rains - https://news.ycombinator.com/item?id=41727317 - Oct 2024 (2 comments)
Tokyo's Underground Discharge Channel - https://news.ycombinator.com/item?id=19785044 - May 2019 (42 comments)
That second listing links to a piece with lots of good photographs.
https://www.snowyhydro.com.au/wp-content/uploads/2024/01/SH_...
Not the same power station, but I have to post a link to one of my favorite YouTube videos: https://www.youtube.com/watch?v=fJVBlhgt9j8 (Obere Wasserschlosskammer).
I sometimes forget that manga writers use very real locations as references. I believe this is the backdrop for several Tokyo Ghoul scenes.
The earthquakes make it so that what would be a simple overpass has all of this ... stuff that would not exist in a more geologically stable region.
Culture and food were still my main motivations for visiting, but the infrastructure part came as a nice bonus.
https://www.youtube.com/watch?v=y3tdYolqiU8
Also, the rivers around Tokyo all have giant flood areas (parks, golf courses, farms) they can open to hold water in an emergency.
My first thought upon seeing the photos was that this was the inspiration for many of the indoor levels in the original Half-Life. All that's missing are the headcrabs.
I am sure other cities have it as well, but it really looks close to the level.
It's a favourite in the caving community to describe very large, well, cathedrals in cave systems.
