【 CONTENTS 】
- Large underground facility that protects the city from water hazards brought on by typhoons and rain.
- Constructed using the newest civil engineering technologies in Japan
- Reservation required for a tour
Large underground facility that protects the city from water hazards brought on by typhoons and rain.
What is this big space!?
“The Metropolitan Area Outer Underground Discharge Channel” is located in the underground of Kasukabe city, Saitama. It is the world’s largest underground discharge channel. It takes in water from small-medium rivers underground when it’s about to overflow and adjusts its volume to discharge the water into a big river.
After its completion in 2006, water hazards in Kasukabe and other Metropolitan areas clearly decreased. It operates 6-7 times a year on average.
The space shown in the photo is called “Pressure adjustment tank”, which is where the flooded water is stored temporarily. It is 177m long, 78m wide, and 18m tall. It is supported by 59 reinforced concrete pillars.
Constructed using the newest civil engineering technologies in Japan
“The Metropolitan Area Outer Underground Discharge Channel” is a facility constructed 50m under the ground. When you create such a huge pressure adjustment tank underground, there’s a risk that the uplift pressure of underground water may lift up the tank. The 59 reinforced concrete pillars, weighing 500tons prevent this from happening.
Other parts include a massive shaft, 30m in diameter and 70m in depth, which is used to take in the water, as well as a 14000 horsepower turbine capable of discharging water at a rate of 200㎥/second. Everything about this facility is massive in scale.
Reservation required for a tour
“The Metropolitan Area Outer Underground Discharge Channel” holds 3 tours per day, taking 25 people around each session. Tour is only available on weekdays. If you make reservations ahead of time, anybody can join the tour. Why not come and witness the massive underground facility?
The ground is slippery, so please wear sneakers. You cannot join the tour wearing high heels or sandals.
The tour will be conducted in Japanese, so bring a friend who is fluent in Japanese with you. For more details, see this page.