Devastating and deadly floods are frequently seen in the entire history of Japan. This is quite natural as Japan is an island country. These floods do a lot of damage to Japan’s population, economy, flora, and fauna. As a measure against this constant flooding, the Japanese started to think of ways to stop waterlogging. An idea was found and the execution was started in the 1920s. It is called the G-Cans project. Popularly, it is called as world's Biggest Drains. It was commissioned in 1992. The simplicity of the concept will make you marvel.
The idea was to expand the drainage system of Tokyo to huge volumes by underground constructions. All the existing rivers and waterways are already connected to the ground drainage system of Tokyo. This ground drainage was connected to the huge underground drains.
This underground system is a group of 5 massive cisterns in the shape of a cylinder. NASA could store its space shuttle in these cisterns. They are about 70 meters high and have a diameter of 30 meters. All these 5 cisterns are interconnected by tunnels buried 50 meters deep under the ground and 10 meters wide.
From the start of its construction in 1993, it took 13 years to complete the G-CansProject with an expense of approximately $3 billion US dollars, by the end of2006. A beautiful, state-of-the-art control room is responsible for the operation of these G-Cans. The water from the G-Cans is lodged into a huge enormous pressure-controlled tank. The tank has an enormous dimension of 180 meters in length, 80 meters breadth, and 18 meters in height. This tank is used to break the flow of incoming water by providing hurdles. These hurdles are 59 pillars weighing 500 tons each. They also support the ceiling of the tank. The solution is indeed an Engineering and Architectural masterpiece.