A 185-ton dock that was swept from Tohoku by the 2011 tsunami and reached a remote coastal area of Washington state will be dismantled and removed by helicopter this month, the U.S. National Oceanic and Atmospheric Administration said.

The removal costs are estimated at around $628,000 (¥58.8 million). The majority of these funds, some $478,000, is expected to come from the $5 million (¥468 million) provided by Japan to clean up tsunami debris crossing the Pacific and washing ashore on the U.S. West Coast.

The dock was one of four ripped from the port of Misawa, Aomori Prefecture, by the March 11 tsunami triggered by the Great East Japan Earthquake. It beached at Washington's Olympic National Park in mid-December, and has since been monitored by state and local agencies.

Meanwhile, officials forecast that another dock originating from Tohoku that washed up on a beach in Oregon last June will cost around $84,000 (¥7.9 million) to remove. To date, NOAA has identified 21 items of tsunami debris that have made it to U.S. shores or nearby waters.