Shimizu develops ‘green’ cones for tsunami defense


General contractor Shimizu Corp. has developed conical “green hills” that would delay the entry of tsunami if placed along the coast, and could also serve as evacuation sites.

The height of each hill would be 10 to 15 meters.

The hills will be made partly with debris from the March 2011 earthquake and tsunami, with their surfaces to be covered with plants.

Shimizu said it wants to propose the green hills to vulnerable coastal communities.

The area at the top of each hill would be as large as 2,000 sq. meters and could accommodate up to 1,300 people.

The entry of tsunami could be delayed by several minutes if two or more hills are placed along the shoreline, Shimizu officials claimed.

It will take six to 18 months to build one hill, with construction costs ranging from ¥100 million to ¥500 million.

The hills can be built faster and more cheaply than seawalls, the officials said.