Tokyo's Flood Defense 'Cathedral': Battling Guerrilla Rains

Just north of Tokyo lies the Metropolitan Outer Area Underground Discharge Channel, a robust flood defense system. Known as 'the cathedral,' it helps manage severe rainfall and flooding exacerbated by climate change. Despite its success, rising extreme weather events necessitate upgrades and new projects to enhance Tokyo's infrastructure.

In the early hours of August 30, a remarkable flood defense system known as the 'cathedral' swelled with water as Typhoon Shanshan drenched the Tokyo region. Located just north of the metropolis, the Metropolitan Outer Area Underground Discharge Channel effectively prevented flooding in a susceptible river basin.

The system, comprising a vast network of tunnels, has become crucial as climate change intensifies severe weather. University of Tokyo professor Seita Emori highlights that rising temperatures lead to more water vapor and heavier rainfall, forecasting increased strain on such infrastructure.

Since 2006, this engineering marvel, also a tourist attraction, has mitigated over 150 billion yen in flood damage. However, guerrilla downpour patterns have prompted further enhancements, including a 37.3 billion yen project to reinforce levees and expand drainage, ensuring Tokyo remains resilient against future deluges.

(With inputs from agencies.)