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Japan’s Tsunami defence system

Sea wall construction in northeast Japan is going on at brisk pace

By Telangana Today

Published Date - 7 March 2021, 09:22 PM

Years after a towering tsunami ravaged much of Japan’s northeastern coast, efforts to fend off future disasters are focusing on a nearly 400-kilometer (250-mile) chain of cement sea walls, at places nearly five storeys high. Sea wall construction in northeast Japan is going on at brisk pace. Let’s read more about the country’s tsunami defence system.

When a massive earthquake struck in 2011, Japanese oyster fisherman Atsushi Fujita was working as usual by the sea. Soon after, a huge black wave slammed into his city and killed nearly 2,000 people.

Ten years on, Fujita and thousands like him along Japan’s northeast coast have rebuilt their lives alongside huge sea walls that experts say will protect them if another giant tsunami, which some see as inevitable in a seismically active nation like Japan, was to strike.

High sea wall to fight tides

The 12.5-meter (41-ft) concrete wall replaced a 4-meter breakwater that was swamped in the March 11, 2011 disaster. The earthquake and tsunami, which reached as high as 30 meters in some areas, killed nearly 18,000 people across Japan and triggered a nuclear meltdown at the Fukushima power plant.

Green wall stood strong

A 7.2-meter (24-foot) -high sea wall built years earlier to help stave off erosion of Iwanuma’s beaches slowed the wall of water, as did stands of tall, thin pine trees planted along the coast. But the tsunami still swept up to 5 kilometers (3 miles) inland.

The city repaired the broken sea walls but doesn’t plan to make them any taller. Instead, Iguchi was one of the first local officials to back a plan championed by former Prime Minister Morihiro Hosokawa to plant mixed forests along the coasts on tall mounds of soil or rubble, to help create a living “green wall” that would persist long after the concrete of the bigger, man-made structures has crumbled.

Opposition to plan

Opponents of the 820 billion yen ($6.8 billion) plan argue that the massive concrete barriers will damage marine ecology and scenery, hinder vital fisheries and actually do little to protect residents who are mostly supposed to relocate to higher ground. Those in favor say the sea walls are a necessary evil, and one that will provide some jobs, at least for a time.
In the northern fishing port of Osabe, Kazutoshi Musashi chafes at the 12.5-meter (41-foot)-high concrete barrier blocking his view of the sea.