Tokyo

Metropolitan Area Outer Underground Discharge Channel (Flood Control)

Greater Tokyo, Japan

Highlight

One of the world's largest underground stormwater systems, diverting flood water into vast tanks and tunnels.

Extended description

The Metropolitan Area Outer Underground Discharge Channel (MAOUDC) is one of the world's largest flood-control infrastructures, protecting greater Tokyo from heavy rain and typhoons. A network of huge underground tunnels, massive reservoirs (including a cathedral-like surge tank) and powerful pumping stations collects excess rain and river water and discharges it safely to a major river, sharply reducing urban flooding in a low-lying metropolis.