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Tsunami Debris Poses Continued Threat to Alaska

Landing craft load of tsunami debris being readied for transport in 2013.

Landing craft load of tsunami debris being readied for transport in 2013.

Photos courtesy of Airborne Technologies, Inc. ~ Gulf of Alaska Keeper ~ Island Trails Network

The 2011 Tohoku tsunami in Japan claimed 19,300 lives and washed 5 million tons of debris into the sea.

Of that, approximately 30 percent of Japan Tsunami Marine Debris (JTMD) remained afloat and was set adrift in the Pacific Ocean. A study conducted by Washington Sea Grant estimated that although Washington state would be largely spared, between 15,000 tons and 187,000 tons of that debris would eventually make landfall in Alaska. Oceanographers initially estimated it would take several years for JTMD to reach our shores, but certain types of tsunami debris began washing ashore in Alaska in November 2011, only eight months after the tsunami struck, and it continues today.

In 2012, the Alaska Department of Environmental Conservation (ADEC) commissioned an aerial survey of the Gulf of Alaska to assess the impacts of tsunami debris on the outer shores of the Alaska coast from Southeast Alaska to the Kodiak Archipelago. The survey, conducted in July and August 2012, confirmed widespread anecdotal reports that large quantities of tsunami debris made landfall, especially in areas traditionally associated with marine debris. The results of the aerial survey were discussed in early 2013 at a tsunami debris prioritization workshop organized by the National Oceanic and Atmospheric Association (NOAA) and attended by state and federal natural resource and land management agencies, Native groups and conservation non-profits. The workshop kicked off an ongoing process of ranking of 44 designated shoreline segments based on habitat value, biodiversity, socio-economic importance, cultural value and cleanup feasibility.

NOAA and ADEC funded a pilot tsunami debris cleanup in September 2012 in Prince William Sound. This project confirmed the presence of widespread tsunami debris, particularly Styrofoam, even in protected waters. The Alaska Legislature then took the lead and funded an early cleanup response that removed more than 200 tons of tsunami debris and other marine debris in 2013. The Exxon Valdez Oil Spill Trustee Council also funded a JTMD cleanup in Prince William Sound in 2013 that removed an additional 70 tons of tsunami debris from critical habitat. Some northern Gulf of Alaska shorelines hold up to 30 tons of plastic marine debris per mile with half of that being tsunami debris. With less than 500 miles of Gulf of Alaska shoreline cleaned to date, the cleanup response has only started.

One of the many piles of tsunami debris collected by Gulf of Alaska Keeper on Montague Island

One of the many piles of tsunami debris collected by Gulf of Alaska Keeper on Montague Island in 2013.
 

In spite of Alaska's proactive response to the threat, with between 5,000 and 10,000 miles of mostly uninhabited coastline yet to be cleaned, Alaska continues to be more vulnerable to JTMD than any other state. A recent NOAA report claimed that, "While other states also received debris, the density of debris in Alaska combined with its rugged shorelines meant that debris detection, assessment and removal were more challenging, and what could be accomplished through volunteer engagement was limited in comparison to other states.” Agencies and non-governmental organizations from around the state continue to seek funding and other resources to combat the new threats caused by tsunami debris, including hazardous materials and invasive species in addition to the easily evident traditional threats of entanglement and ingestion.

So far, ADEC has received $1 million for marine debris removal in 2014, from a $5 million "gift" from the government of Japan to the United States for JTMD response and removal. These funds will clean an estimated 100 miles of coastline and remove an estimated 100 tons to 200 tons of JTMD and other marine debris. The combined results of these efforts will rehabilitate about 5 to 10 percent of the worstaffected shorelines of Alaska, and less than 1 percent of the critically impacted coastline. A coalition of coastal stewardship groups consisting of Gulf of Alaska Keeper, Island Trails Network, and Airborne Technologies, Inc. is seeking a $5 million appropriation from the Alaska Legislature to extend cleanup effort into future years.

In the Pacific Northwest, the cleanup was expensive, but relatively straightforward. Washington and Oregon had requested emergency relief from the Gift of Japan funds in the amount of $750,000 and $500,000 respectively. The majority of these funds were used to remove the well-publicized Misawa docks, one of which washed ashore in each of those states in 2012. In spite of the attention surrounding the Misawa dock, Washington has received relatively few other reports of tsunami-related debris and dismantled their tsunami debris hotline on Dec 31, 2013. Oregon's Department of Fish and Wildlife maintains an active watch of their 400 miles of coastline, and is primarily concerned with fending off invasive aquatic species.

Gulf of Alaska Keeper cleanup workers removing tsunami debris from Montague Island

Gulf of Alaska Keeper cleanup workers removing tsunami debris from Montague Island in 2013.
 

As Alaska braces for a continued influx of JTMD, it remains extremely difficult to distinguish tsunamirelated debris from common marine debris, of which a large percentage also originates from Japan and other Western Pacific countries. As the three-year anniversary of the tsunami approaches, only 43 items found in the U.S. have been positively traced back to their point of origin in the tsunami impacted area.

But more of those confirmed discoveries have occurred in the past 12 months than in the first two years after the event, indicating that JTMD accumulation rates may still be on the rise. For every confirmed discovery of tsunami-related debris, there are millions of pieces of debris that cannot be positively identified, but likely washed into the sea on March 11, 2011. Continued survey and cleanup is critical to understanding the full effect of this natural disaster on Alaska's shores and preventing pollution incidents and the proliferation of invasive species.

NOAA continues to track reports of JTMD and may be reached at disasterdebris@noaa.gov.

 

SOURCE: Gulf of Alaska Keeper | Island Trails Network | Airborne Technologies

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