Metropolitan Area Outer Underground Discharge Channel [2006] - world's largest underground flood water diversion facility in Kasukabe, Japan

It consists of five concrete containment silos with heights of 65 m and diameters of 32 m, connected by 6.4 km of tunnels, 50 m beneath the surface, as well as a large water tank with a height of 25.4 m, with a length of 177m, with a width of 78m, and with 59 massive pillars connected to 78 10 MW (13,000 hp) pumps that can pump up to 200 tons of water (the approximate equivalent of a standard 25 meter pool) into the Edo River per second.

Johannes Reponen