Shimizu Proposes Green Mounds for Tsunami Defense

November 26, 2012 (Spoon & Tamago)

 Image: Anti-tsunami mounds would be placed in vulnerable coastal communities.

Shimizu Corporation last week announced a proposal to build low-tech, low-cost “green mounds” in areas with an elevated risk of being struck by a tsunami. The hills, which would rise between 10 and 15 meters, would be constructed from last year’s tsunami debris and would serve primarily as an evacuation site that would delay the entry of tsunamis. The structure of the mounds, the company states, would absorb the force of the tsunami, rather than push against it the way conventional seawalls are designed to do.

The mounds would come in 3 sizes – small, medium, and large. A small mound will accommodate 50 evacuees, would cost 100 million yen (about $1.3 million) and could be built in about 6 months. On the higher end, a large mound will accommodate 1,300 evacuees, would cost 500 million yen (about $6.3 million) and would take 18 months to build.

Below are some of the specs that the company lists:

Small Mound Medium Mound Large Mound
Height 10m 15m 15m
Evacuee Capacity 50 470 1300
Cost 100 million yen 250 million yen 500 million yen
Construction period 6 months 12 months 18 months

It’s hard to take this company serious given their history of large-scale imaginative yet wholly impractical proposals. However, this idea seems a bit more realistic than their 6,800 mile long “Luna Ring” of solar panels that wrap around the moon. Or their floating islands with cities in the sky.