Marvel at the Vast, Cathedral-like Underground Structure
Witness Cutting-edge Flood Control Technology in Action
Explore a Hidden Architectural Wonder beneath the City
How to Get There by Train
Minami-Sakurai Station: Tobu Noda Line (Tobu Urban Park Line)
It’s about a 30-minute walk from the station. You can also take a bus or taxi from the station entrance.
What’s It Like?
The Metropolitan Area Outer Underground Discharge Channel is a massive underground water discharge system designed to prevent flooding and water damage. This system captures excess water from rivers through five main intake facilities and channels it into a large underground pressure-adjusting water tank. The tank is 18 meters high, 177 meters long, and 78 meters wide. The stored water is then funneled through a 6.3-kilometer-long discharge tunnel located 50 meters underground with a diameter of 10 meters. Finally, the pumping station discharges this water into the Edogawa River, preventing urban flooding.
The primary goals of this discharge channel are to reduce flood damage, protect urban infrastructure, and improve regional safety. Tokyo and its surrounding areas are particularly vulnerable to flooding, especially during typhoons and heavy rains. This system aims to prevent river overflow and minimize urban flood damage. Additionally, by protecting critical urban infrastructure from water damage, it helps maintain economic activity and daily life. Reducing flood risk also enhances the safety and quality of life for residents. Due to its scale and technical innovation, the Metropolitan Area Outer Underground Discharge Channel is known as the “Underground Temple” and has become a popular tourist attraction.
The construction of this facility began in 1993 and was completed in 2006.
Notice: Please refer to THIS SITE for tour details. If you request my services as an interpreter, please ensure tickets are prepared in advance, including one for the guide. Pick-up locations can be at a hotel in Tokyo, Omiya Station, or Minami-Sakurai Station. The guide fee will be charged according to the time required.
