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Quantitative shoreline change analysis of an inlet-influenced transgressive barrier system : Figure Eight Island, North Carolina

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Chester W. Jackson Jr. (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/
Advisor
William Cleary

Abstract: GIS-based analyses of NOS T-sheet maps, aerial photographs, LIDAR, and RTK GPS shoreline data spanning the time period from 1857 to 2003 were conducted to quantify shoreline rate-of-change values for Figure Eight Island, North Carolina. Four zones (I, II, III, & IV) were delineated along the island to summarize variations of shoreline change trends in response inlets, storms, and anthropogenic activity. Long-term mean annual erosion rates prior to island development ranged between -4.4 to -0.8 ft/yr (±0.39 ft/yr) along zones I through III, which account for the approximately 90% of the island’s shoreline, and +5.6 ft/yr (±0.96 ft/yr) along Zone IV. Subsequent to development in 1966, shoreline change rates ranged between -1.7 to +5.8 ft/yr (±0.84 ft/yr) along zones I through IV. The overall long-term mean annual erosion rate during the period from 1857 to 2003 ranged between -1.8 to -0.4 ft/yr (±0.24 ft/yr), along zones I through III, and +2.1 ft/yr (±0.36 ft/yr) along Zone IV between 1927 and 2003. Zones I and IV, adjacent to Mason Inlet and Rich Inlet respectively, are dominated by inlet processes associated with movements of the ebb channel and changes in ebb-tidal delta symmetry. Zone II is mainly impacted by a mixture of storms, tides, longshore transport, and some inlet processes. Longshore transport reversals, associated with wave refraction downdrift of Rich Inlet’s ebb delta inflection point, influence Zone III. Thorough shoreline and inlet management plans are critical for mitigation against imminent beach erosion. Innovative alternatives such as ebb shoal mining might provide needed beach nourishment material, as sand resources in the offshore and backbarrier are limited. However, detailed studies are needed to establish both short- and long-term impacts of human activities on shoreline morphology.

Additional Information

Publication
Thesis
A Thesis Submitted to the University of North Carolina at Wilmington in Partial Ful¯llment Of the Requirements for the Degree of Master of Science
Language: English
Date: 2009
Keywords
Shorelines--North Carolina--Figure Eight Island
Subjects
Shorelines -- North Carolina -- Figure Eight Island