State of the Beach/State Reports/AK/Beach Erosion
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Less than 1% of Alaska's shoreline is critically eroding, according to the report "State Coastal Program Effectiveness in Protecting Natural Beaches, Dunes, Bluffs, and Rock Shores," (T. Bernd-Cohen and M. Gordon), Coastal Management 27:187-217, 1999.
Approximately 95-99% of the coastline has no dry sand at high tide.
Alaska's 2001 Assessment indicates:
Wind, tide, running water, and other forces or actions, such as public works projects, cause erosion. Efforts to control erosion in one locale can increase the erosion elsewhere. Shoreline erosion only becomes a "problem" if man has built too close to the shore. Beaches naturally shift position in response to storms and sea level changes. Wherever there is water or wind action against the land, erosion occurs. Ice scour and permafrost thaws accelerate the problem. Glacially deposited silt and gravel bedded valleys, common in Alaska, are materials that erode easily. Because communities use rivers and the ocean for transportation, shipping, and sustenance, many communities are adjacent to a river or beach. In 1975, a state committee identified 35 communities where erosion is considered critical. In 1984, a state task force identified 62 communities with known erosion problems.
Erosion rates can be significant. For instance, the Matanuska River had in the past cut as much as 90 feet of riverbank in 4 days. Some communities lose 10-20 feet annually. In some places, the whole community is threatened by erosion. The majority of the coastal bluff properties within the City of Homer are threatened due to chronic coastal erosion. The Homer Spit has significant erosion, an impact from the 1964 earthquake. Because the plate dropped about three feet, the entire perimeter of land adjacent to Homer is washing to sea. Homer has been working with the federal government to protect homes and to keep the spit open. The village of Shishmaref may have to relocate because it is affected by coastal erosion from harsh storms. Other Alaskan communities including Barrow, Kivalina, Newtok and Point Hope are also looking at relocation as a possibility due to severe coastal erosion.
Some coastal rivers and streams are being slowly transformed due to efforts driven by residents, government agencies, and non-profit groups to protect important fishery and natural resources. The improvements — or sometimes lack of development — are generally also good for reducing erosion and flood losses. Multi-objective management approaches for shoreline rehabilitation and protection should pay off in reductions in flood and erosion losses. These approaches have occurred along the Kenai River (funded by Exxon Valdez oil spill funds), Ship Creek, and the Mendenhall Watershed Partnership. Mass wasting, the slow down-slope movement of rock and debris, is related to degree of slope and types of soils and vegetation. Deforestation from resource extraction operations - such as timber harvest and mining that require the removal of the current vegetative cover - can result in mass wasting. The Forest Practices Act (FPA) has considered mass wasting in its best management practices (BMPs).
The Governor of Alaska signed a State Erosion Management Policy in June 1998. The Policy provides general guidance to state agencies for state funded and state pass-through funded construction. State agencies and other entities are encouraged to develop more detailed guidance in their respective programs. Federal, state, and local governments have funded or built erosion control structures with mixed results as the effectiveness of structural erosion control techniques has not been analyzed on a statewide basis.
In Homer (mentioned above) homeowners on Kachemak Drive are concerned as the bluff their homes are built on continues to crumble into the sea. Although this area is in a "moderate" erosion zone (0.7 to 0.9 meters per year according to Steve Baird of Kachemak Bay Research Reserve), the erosion on Kachemak drive may have been exacerbated by weekly flushing of a fire hydrant by the city and a state-built road that dams the water. Saltwater Drive, Munson's Point and Overlook Park experience higher erosion rates, with Munson's Point eroding at an average of 1.2 to 1.5 meters per year.
At Kivalina (mentioned above), about 100 to 110 feet of the town's 600-foot beachfront have disappeared into the ocean in the last four or five years. At Newtok, the entire village is planning to relocate to a hilly area called Mertarvik on Nelson Island. They completed a federal land trade in 2004. The current site is continually squeezed by the Ninglick River, which has eaten an average of 70 feet of bank a year just south of the village.
According to an erosion study done by Steve Baird of the Kachemak Bay Research Reserve, the mouth of Stariski Creek, along the Cook Inlet coast south of Ninilchik, has moved 1.4 miles since 1951. The creek has been moving parallel to the coast, with the bank on its seaward side building up, choking off Hawk's Beach and increasing erosion there. The Ninilchik State Recreation Area has been eroding for about 20 years, but a 2010 storm took out enough beachfront to wipe out 30 campsites and force closure of the campground. State parks officials and the Southern Kenai Peninsula State Parks Citizens Advisory Board toured the Ninilchik area and Deep Creek State Recreation Area in November 2013, the Peninsula Clarion reported. A “perfect storm” combination of a high tide and high wind caused the ocean to wash about 15 feet of beach out from behind during a September 2012 storm, causing the loss of about 15 campsites at Deep Creek.
The US Army Corps of Engineers has conducted a study to provide an overall assessment of erosion in the State of Alaska. The Corps, working with the State, Federally recognized Tribes, and other stakeholders, developed an Alaska Baseline Erosion Assessment (March 2009) to provide a measured assessment of erosion issues in Alaska. This study provides communities affected by erosion with an estimated erosion rate map, potential recommendations, and guidance for implementation on ways they can address their concerns. Through a process of stakeholder meetings, researching previous reports and extensive correspondence with communities, 178 Alaskan communities reported having erosion issues. These communities were investigated, documented and then rated to determine their individual need for action. The Appendices of the report include detailed Erosion Information Papers for 22 Priority Action Communities.
The following text is from the Executive Summary of the Alaska Baseline Erosion Assessment report.
Through a process of stakeholder meetings, review of previous reports, and extensive correspondence with communities, 178 Alaska communities were found to have reported erosion problems. After subsequent investigation, the Corps designated 26 communities “Priority Action Communities” — indicating that they should be considered for immediate action by either initiating an evaluation of potential solutions or continuing with ongoing efforts to manage erosion. Sixty-nine communities where erosion problems are present but not significant enough to require immediate action were designated “Monitor Conditions Communities.” Eighty-three communities where minimal erosion-related damages were reported or would not be expected in the foreseeable future were designated “Minimal Erosion Communities.”
The 26 Priority Action Communities are Akiak, Alakanuk, Barrow, Chefornak, Chevak, Clark’s Point, Cordova/Eyak, Deering, Dillingham, Emmonak, Golovin, Huslia, Kivalina, Kotlik, Kwigillingok, Lime Village, McGrath, Napakiak, Newtok, Nunapitchuk, Port Heiden, Saint Michael, Selawik, Shaktoolik, Shishmaref and Unalakleet.
Each Priority Action Community has reported serious erosion that is threatening the viability of the community, or, in some cases, significant resources are being expended to minimize those threats. The erosion issues in these communities warrant immediate and substantial Federal, State, or other intervention. In some cases, action is needed to continue funding for projects that are underway and funded by Federal, State, Tribal, and/or local entities. For others, it is urgent that a team visit the community to assess erosion issues and needs thoroughly.
A topic that arose frequently during the BEA study is that flooding is as great a problem as erosion in some communities. The BEA assesses erosion but includes a conclusion that an assessment of flooding issues in Alaska is needed.
Communities can address erosion issues using various self-initiated activities and by seeking assistance from State and Federal agencies.
The most appropriate response is prevention. Communities and those assisting communities with construction should not build structures within the 50-year erosion hazard zone or 50-year flood hazard zone. If such construction must occur, structures should be designed for ease of relocation, and prior construction in those zones should be retrofitted for the same purpose. These actions can do much to reduce the potential severity of erosion damage.
There are several expedient measures a community can use to construct temporary protection. Measures such as sandbag revetments, sand placement, and use of vegetation can be implemented by using local materials or material that can be brought in by airplane quickly.
Although the State of Alaska has no formal erosion control program, the State has capability to take action in addressing erosion. Through specifically funded projects and coordinated actions such as the Newtok Planning Committee and the Immediate Action Workgroup, the State is a collaborative leader in developing solutions.
The Natural Resources Conservation Service (NRCS) has programs that can provide erosion control assistance. NRCS administers the Watershed and Flood Prevention Program. The Watershed Protection and Flood Prevention Act (PL 83-566) of 1954 authorized NRCS to cooperate with states and local agencies to carry out works of improvement, including projects to prevent erosion damages.
The Corps has several cost-shared programs that communities can utilize for assistance. Section 14 of the U.S. Flood Control Act of 1946 allows the Corps to plan, design, and construct erosion control projects that protect public infrastructure. Section 103 of the U.S. River and Harbor Act 1962 is used for protection against storm waves and hurricanes.
The Corps’ authority to construct solutions for erosion control in Alaska has been modified by the repeal in March 2009 of Section 117 of the 2005 Energy and Water Development Appropriations Act. Section 117 had allowed projects constructed under that authority to be funded at full Federal expense, and did not require that those projects be justified by using the traditional benefit-cost ratio test. Under Section 117, the Corps has been able to initiate construction at Kivalina, Newtok, Shishmaref, and Unalakleet. Because of the repeal of Section 117, it is unknown whether these projects can be completed as planned.
Alaska's 2011 Coastal Assessment and Strategy reports:
- "There was an erosion rate study in Kenai Peninsula Borough in FY09 and FY10. In FY10 Division of Geological and Geophysical Surveys began a revision of its hazards database to increase its utility for coastal district coordinators in building evidence and support for hazards maps, designations, and policies. Additionally, the Alaska Division of Geological & Geophysical Surveys (DNR-DGGS) is initiating a coastal community geohazards evaluation and geologic mapping program in support of community and district planning. Also in FY10 as part of a Natural Hazards Resiliency project there was literature gathering on resiliency in hazards planning. The Division of Coastal and Ocean Management Alaska sponsors Conferences and District Workshops that provide coastal management education to coastal coordinators and the public. The 2007 Statewide Conference sessions included “Coastal Erosion/Hazard Mapping” and a separate discussion of the Natural Hazards ACMP Statewide Standard. The 2009 Northern District Workshop featured presentations by a natural hazards panel with representatives from USGS, Geological staff of Division of Geophysical and Geological Surveys, and an academic professor in Environmental Geology."
In July 2015 the U.S. Geological Survey published a report National Assessment of Shoreline Change: Historical Shoreline Change Along the North Coast of Alaska, U.S.-Canadian Border to Icy Cape. USGS scientists found that the remote northern Alaska coast has some of the highest shoreline erosion rates in the world. Analyzing over half a century of shoreline change data, scientists found the pattern is extremely variable with most of the coast retreating at rates of more than 1 meter a year. Scientists studied more than 1600 kilometers of the Alaskan coast between the U.S. Canadian border and Icy Cape and found the average rate of shoreline change, taking into account beaches that are both eroding and expanding, was -1.4 meters per year. Of those beaches eroding, the most extreme case exceeded 18.6 meters per year.
In September 2015 the Alaska Shoreline Change Tool was launched. This online mapping tool lets viewers look at past erosion and see where coastlines might be in future years. It was created by Alex Gould, a geologist for Alaska Division of Geological and Geophysical Surveys (DGGS). Over the previous year, Gould created clickable shoreline maps for Port Heiden, Unalakleet, Wales, Kivalina, and four other locations on the Beaufort and eastern Chukchi sea coasts. In the near future DGGS may add online maps for Shaktoolik, Nome, and Hooper Bay, among other communities.
Additional coastal erosion studies in Alaska include:
- USGS Press Release Erosion Doubles Along Part of Alaska’s Arctic Coast
- USGS Science in Alaska: National Assessment of Shoreline Change Project, Alaska. Also see here.
Coastal erosion is a growing problem in many areas of North and West Alaska, along the Beaufort Sea and Bering Sea. The coastal erosion is a result of permafrost melting under the soil. The areas become less stable and very vulnerable to storms. This may be direct evidence of global warming. Similar problems are occurring in the Arctic that may be linked to global warming.
USGS scientists completed a quantitative analysis, published in the July 2007 issue of Geology, documenting effects of accelerated coastal land loss and thermokarst lake expansion and drainage along a section of the Alaska North Slope coastline. The remote sensing analysis focused on the Beaufort Sea coast, located north of Teshekpuk Lake in the National Petroleum Reserve in Alaska. The data used in the analysis span the time frame 1955-2005 and consisted of 1955 USGS topographic maps, and 1985 and 2005 Landsat 5 Thematic Mapper data. From these data, USGS scientists found that the rate of land loss attributed to coastal erosion more than doubled, from 0.48 km2 per year during 1955–1985 to 1.08 km2 per year during 1985–2005.
For a compelling visual illustration of coastal erosion driven by permafrost melting, see here.
A concern related to the increased erosion in this area is that old oil wells could be swallowed by the ocean as the coastline retreats. The Bureau of Land Management (BLM) has identified about 30 old oil exploration wells that need to be cleaned up and plugged before the sea claims them. The BLM has already cleaned up and plugged the J.W. Walton well in 2005 after more than 300 feet of shoreline was eaten away in a single summer. That well is now underwater.
An article by Elizabeth Bluemink in the Anchorage Daily News on January 19, 2008 highlighted the pollution problems that seem to be increasingly occurring as coastal erosion exposes landfills, hazardous waste dumps and oil production facilities. A December 2009 article in the Alaska Journal of Commerce highlighted additional concerns related to increased coastal erosion.
A potential project identified in the 2001 Assessment consists of erosion mapping, development of policies, and planning. The key elements would include:
- Develop a state policy on when to fund erosion control structures vs. when to encourage gradual relocation of a community by constructing public facilities away from erosion area.
- Develop zoning and development siting guidelines.
- Provide information for communities on land regulation, public education, and other alternatives to address key erosion problems.
- Lead to engineering standards for foundation footings in coastal hazard areas that allow for fill, or improve permitting of column/pile foundations so federal standards are met.
The lack of erosion rate data and mapping of erosion prone areas has been identified as a current ACMP shortcoming that could be addressed through the Enhancement Grants Program. Erosion hazards have a variety of suitable responses depending on geology, geography, development patterns, economic viability, and other factors. While shoreline armoring such as revetments, and other hard protection techniques may be suitable in some situations, long range considerations, littoral drift, riverine sediment transport, and other physical processes, and availability of upland development sites, may make other management techniques equally if not more attractive. Erosion issues are complex and have been a divisive issue in many lower 48 states. Alaska has a good opportunity to proactively address the issue and develop state guidelines for implementing erosion mitigation techniques.
Mapping of erosion-prone areas is a key first step to improving the ACMP in this area. Alternatives exist for work beyond this effort, including developing state erosion mitigation guidelines, developing district-specific zoning/development siting guidelines, and developing engineering standards for development projects sited in erosion hazard areas. A pilot project in a single coastal district would be a useful way of examining these choices and issues, serving as a model for other coastal areas.
Public education is an important aspect of any project dealing with erosion. A broad based public awareness of coastal hazard risks may lead to support for mitigation actions. Mitigation training will be a critical element to insure effective implementation of program changes.
Various state guidelines addressing erosion could be developed from such a project. As mentioned, developing state erosion mitigation guidelines, developing localized zoning/development siting guidelines or district coastal management plan enforceable policies, and developing engineering standards for development projects sited in erosion hazard areas are all possible. Depending on the nature of the project, zoning guidelines and development policies could be revised and developed as necessary.
Areas for future study and ACMP improvement would also be identified. Revised district coastal management programs would be a likely outcome of this project. Again, public education and outreach will be important during the development of any guidance, and to ensure the public is informed about safe building practices and avoiding hazardous areas.
Alaska's 6,600-mile coastline (excluding bays and fjords) is subject to periodic, yet severe, erosion. Alaska's northern coastline is icebound for most of the year. The ice season lasts from November to April on most of the Bering Sea coast, longer along the Chukchi Sea, and still longer on the Beaufort Sea coast, where it usually lasts 9 to 10 months. Along this northern coastline, Alaska experiences some of the highest erosion rates in the world during its few ice-free months. The high coastal erosion rates generally are caused by seasonal storm surges, the thawing of permafrost, and the breaking off of chunks of shoreline by moving ice; some of the area's barrier islands are moving landward at a rate of 23 feet per year. Other geologic forces such as earthquakes, landslides and land subsidence contribute to the state's erosion problems. In 1964, an earthquake caused huge landslides in Anchorage. In coastal areas surrounding the city, enormous blocks of earth that had been stable for years fell into the sea as the unconsolidated gravel and clay beneath them gave way. Fortunately, there are few if any houses or structures at risk from erosion along this largely barren coastline.
The Alaska ShoreZone Coastal Inventory and Mapping Project, a unique partnership between government agencies, NGOs, and private industry, has been flying helicopters along the entire Alaska shoreline each summer since 2001, collecting high-resolution imagery and detailed classifications of the coast's geologic features and intertidal biological communities. ShoreZone has surveyed Alaskan coasts at extreme low tide, collecting aerial imagery and environmental data for roughly 80% of Alaska's coastal habitats and continues to move towards full coverage each year. This is a great accomplishment, but ShoreZone, with help from NOAA's National Marine Fisheries Service, has done an equally impressive job at making their entire inventory accessible to the public. With the online resources made available by this project, you can fly the coastline, download spatial data and view photos for many purposes, including coastal erosion assessments and community planning for climate change impacts.
Additional coastal erosion information and data may be available from Alaska Sea Grant.
The Heinz Center's Evaluation of Erosion Hazards, conducted for the Federal Emergency Management Agency (FEMA), studied the causes of coastal erosion hazards and proposed a variety of national and regional responses. The study, published in April 2000, concentrates on the economic impacts of erosion response policies as well as the cost of erosion itself to homeowners, businesses, and governmental entities.
A NOAA website that has graphs of sea level data for many coastal locations around the country over the last 40 to 50 years and projections into the future is Sea Levels Online.
NOAA Shoreline Website is a comprehensive guide to national shoreline data and terms and is the first site to allow vector shoreline data from NOAA and other federal agencies to be conveniently accessed and compared in one place. Supporting context is also included via frequently asked questions, common uses of shoreline data, shoreline terms, and references. Many NOAA branches and offices have a stake in developing shoreline data, but this is the first-ever NOAA Website to provide access to all NOAA shorelines, plus data from other federal agencies. The site is a culmination of efforts of NOAA and several offices within NOS (including NOAA’s Coastal Services Center, National Geodetic Survey, Office of Coast Survey, Special Projects Office, and Office of Ocean and Coastal Resource Management) and other federal agencies to provide coastal resource managers with accurate and useful shoreline data.
A related site launched in 2008 is NOAA Coastal Services Center's Digital Coast, which can be used to address timely coastal issues, including land use, coastal conservation, hazards, marine spatial planning, and climate change. One of the goals behind the creation of the Digital Coast was to unify groups that might not otherwise work together. This partnership network is building not only a website, but also a strong collaboration of coastal professionals intent on addressing coastal resource management needs. Website content is provided by numerous organizations, but all must meet the site’s quality and applicability standards. More recently, NOAA Coastal Services Center has developed a Sea Level Rise and Coastal Flooding Impacts Viewer as part of its Digital Coast website. Being able to visualize potential impacts from sea level rise is a powerful teaching and planning tool, and the Sea Level Rise Viewer brings this capability to coastal communities. A slider bar is used to show how various levels of sea level rise will impact coastal communities. Completed areas include Mississippi, Alabama, Texas, Florida, and Georgia, with additional coastal counties to be added in the near future. Visuals and the accompanying data and information cover sea level rise inundation, uncertainty, flood frequency, marsh impacts, and socioeconomics.
Erosion Contact Info
State Coordinator for the National Flood Insurance Program
Hazard Avoidance Policies/Erosion Response
See the Erosion Response section.
- Chas Dense, Coastal Resource Specialist, Surfrider State of the Beach Survey response, January 2004.
|State of the Beach Report: Alaska