2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 1
Presentation Time: 1:35 PM

Utilizing Time-Slice Analysis to Define the Geomorphic Evolution and Unravel the Human Impact on the Outer Banks, North Carolina

AMES, Dorothea V. and RIGGS, Stanley R., Department of Geological Sciences, East Carolina University, Greenville, NC 27858, amesd@ecu.edu

Barrier island evolution of the NC Outer Banks is based on a model developed from process-response studies, field surveys, and time-slice analysis of geo-referenced aerial photos (1932-2003) and topographic surveys (1852-2003) from Kitty Hawk to Cape Lookout. Barrier islands form and evolve in response to natural processes that are driven by storms and sea-level rise. The evolution is cyclical and involves shoreline recession and island narrowing, making the island segment susceptible to inlet formation and overwash. Inlets open and build flood-tide delta shoals, and then close and develop into marsh to become part of the island-widening process. Low island segments experience frequent overwash from smaller storms that build island elevation. Once the island segment is elevated, frequency of overwash decreases, vegetation increases, and storms drive shoreline recession that leads to island narrowing once again. Human intervention prevents inlet formation and overwash thus interrupting the natural evolution of the barrier island. Comparing barrier islands with substantial human modification to those dominated by natural processes illustrates the effect of human interference.

Two sets of barrier islands in eastern NC stand in contrast. Core Banks, to the south, has no paved road and has experienced only minimal human modification. However to the north, island segments are substantially modified with extensive areas of urban development interspersed with island segments of Cape Hatteras National Seashore and Pea Island National Wildlife Refuge lands. These latter, despite being protected from conventional development, are dominated by a highway that serves as a corridor for millions of tourists each year. The maintenance, reconstruction, and relocation of this road has lead to almost continuous modification of the natural dynamics, thus interrupting the natural evolution of these northern islands. Analyzing and comparing data from both areas demonstrate the impact of human intervention on the evolution of the North Carolina Outer Banks.