Just north of Tokyo, Japan, 50 meters below the surface, a vast cathedral-esque tank lays empty for most of the year. The £1.7 Billion project waits patiently. The Metropolitan Area Outer Underground Discharge Channel is the largest water drainage system in the world.
The Silos
5 silos for 5 rivers stand ready to swallow the overflow during heavy rain and Typhoon season (around 1 month per year). These mammoth containers burrow 65 meters into the ground with a diameter of 32 meters. They siphon any surplus water that would otherwise spill out and over into residential areas. All connected by a 6.4km tunnel, the water continues towards the main tank.
The Main Tank
With a floor space of 177m by 78m (around 2 football fields), this awe-inspiring chamber reaches 25.4 meters into the air. Throughout its interior stand a total of 59 pillars preventing the ceiling from meeting the ground.
Its purpose is to store the overflow water, ready to be pumped out into Edo River – the largest and most capacious river in the region. Via 78 10MW pumps, a total of 200 tons is pulled up from the tank every second. That’s equivalent to a 25m swimming pool!
The 1991 Flood
Japan has a long history of extreme environmental events. The frequent typhoons and many mountainous rivers pose a consistent threat to life and property. Over recent decades, thanks largely to developments such as this, the damage and deathtolls have been decreasing.
In 1959, over 9 full days, the Isewan Typhoon took 5,000 lives and caused over $600 million of damage.
In 1991, across the Saitama region, 30,000 homes were flooded over 100 square kilometers. The typhoon took 52 lives.
Under future projections of even more potent weather, project construction began in 1992. By 2009, 17 years later, it was fully completed and operational.
(No Ratings Yet)
Loading...