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Erosion Along The Alaskan Beaufort Sea Coast

Erosion Along The Alaskan Beaufort Sea Coast. K. Chelelgo & W. Nyamajeje. Beaufort Sea Coast Map. The Coast’s Geology. Quaternary Sedimentary Permafrost bluffs: Ice Organics Fine-grained sediments Sand & Gravel beaches Unconsolidated bluff at Kenai. Photo by Orson Smith.

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Erosion Along The Alaskan Beaufort Sea Coast

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  1. Erosion Along The Alaskan Beaufort Sea Coast K. Chelelgo & W. Nyamajeje

  2. Beaufort Sea Coast Map

  3. The Coast’s Geology • Quaternary Sedimentary • Permafrost bluffs: • Ice • Organics • Fine-grained sediments • Sand & Gravel beaches Unconsolidated bluff at Kenai. Photo by Orson Smith

  4. Alarming rates of Erosion! • Study area; 40 mile stretch along Beaufort sea • What rates? • 1955-1979 : 20ft/Yr • 1979-2,002: 28ft/Yr • 2002-2007: 45ft/Yr • Causes? • Declining sea ice cover • Increase in storm power; wave action • Thawing of permafrost • Depletion of sediment supply

  5. How it happens 2. Thaw Subsidence of Permafrost Shores 1. Thawing of Permafrost bluffs Courtesy of Benjamin Jones, USGS Courtesy of Benjamin Jones, USGS 3. Undercutting of Glacially deposited Bluffs The Water Wave Action Courtesy of Benjamin Jones, USGS

  6. Impact on Civil Engineering Works Failure of Infrastructure Courtesy of Smith Orson, 2006

  7. 1.Revetments The shallow slopes provide for wave energy dissipation Structural Solutions Courtesy of Orson Smith • 3.Bulkheads • 2.Seawalls

  8. Structural Solutions • 4. Offshore Breakwaters US Army Corps of Engineers photo

  9. Non-Structural Solutions Beach Nourishment Retreat

  10. Alternative solution; Set-back lines

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