The Metropolitan Area Outer Underground Discharge Channel (Ryu-Q-kan)
- 国土交通省 首都圏外郭放水路（龍Ｑ館）
- Saitama
The "Ryu-Q-kan" facility is located within the "Metropolitan Area Outer Underground Discharge Channel." It is the world's largest underground drainage channel that protects the area from flooding. Various things can be learned about the "underground sensory hole," the models for the channel and the pump equipment, the outdoor drainage in the metro, floods, information about the river, and the like. The regulated water tank located 22 meters underground is 78 meters wide, 177 meters long and 18 meters high, and being around it gives off the feeling as if you were inside the Parthenon with its tall pillars. Touring the regulated water tanks requires reservation.