Metropolitan Area Outer Underground Discharge Channel

The Metropolitan Area Outer Underground Discharge Channel, or G Can's Project, is the world's largest underground waterway created in times of floods. The project started in 1992 and was finally completed in 2009, costing the Japanese government two billion dollars. Water from heavy rainfall and floods channels through the tunnels and is then stored in a large storage tank (25.4 m high and 177 m long) and released into the Edogawa River. The channel extends from Tokyo to Saitama. Visitors can visit this magnificent Metropolita Area Oute Undeground Discharge Channel during dry seasons when it is not being used. This massive waterway system, the G Can's Project, keeps the city of Tokyo and surrounding cities safe from floods and heavy rain.