In 1991, a typhoon flooded 100 km², destroying more than 30,000 homes and killing 52 people. To avoid this, Japan began to create underground channels to prevent these floods. So Tokyo and some metropolises in Japan are fully protected from floods of rain, typhoons and tsunamis. Although the city is full of buildings and tunnels under the ground, they are almost invisible to those on the surface.
One of these tunnels is the 4.5km Kanda River Underground Retention Basin in a tunnel 40 meters below ground. This basin can hold up to 540,000 tonnes of water when Tokyo is hit by floods. In Osaka we have the Hiranogawa reservoir, with 1.9 km to prevent flooding. There are several other small underground facilities, but today we are going to talk about the largest in the world.
G-Cans - The underground temple
There are underground constructions in Tokyo that started in the 90's and have pillars that weigh 500 tons. In this case, we are talking about the G-Cans Project, an underground facility to divert localized water from Tokyo to the Edogawa River. This facility has turbines and 78 pumps capable of draining more than 200 tons of water per second. There are 6.4km of tunnels, 50 meters below the surface and it cost more than 3 billion to make.
The site is used a few times a year, you can visit this underground temple for free from Tuesdays to Fridays for an hour and a half. For this you must register in advance on the website below. We will also leave the address of the place.
- Website: www.ktr.mlit.go.jp/edogawa/gaikaku/english/index.html
- Address: 2nd Floor at Ryukyukan reception, 720 Kamikanasaki, Kasukabe city, Saitama 344-0111
- Telephone: +81 48-746-0748