TIME-SLICE ANALYSIS OF GEOMORPHIC--ECOLOGIC SYSTEMS AND DECADAL-SCALE BARRIER ISLAND EVOLUTION, NORTH CAROLINA OUTER BANKS

The evolution of geomorphic features, associated ecosystems, and process-response dynamics, is being studied utilizing time-slice analysis of aerial photographs on the NC Outer Banks. The study is based upon 22 sites between Kitty Hawk and Cape Lookout, NC including the "severely human modified" northern Outer Banks (Cape Hatteras National Seashore--CHNS) and the "more natural" Core Banks (Cape Lookout National Seashore--CLNS) barrier island systems. Selected sites represent all basic variables within the geologic framework, physical processes, and biological ecosystems that characterize these barriers.

Georeferenced aerial photographs (1932--present) and surveyed topographic maps where available, were acquired and computer processed. The geomorphic and ecologic units within each site were identified through field surveys utilizing recent georeferenced aerial photography. These units were then mapped on the georeferenced 1998 digital orthophoto quarter quads (DOQQs) using MapInfo and ArcView. Additionally, a series of detailed maps, sketches, photographs, and aerial photograph time series were developed for each site to demonstrate specific zonations, geomorphic-ecologic associations, and process-response features. Beginning with the recent systems map, mapping proceeds systematically backwards through time utilizing the older aerial photograph sets. Since interpretation of older photographs is more difficult, fewer map units are utilized. Mapping the geomorphic--ecologic system changes through time allows for differentiation of natural barrier island processes and responses from the increasing impacts of human modification and intervention. The geologic evolution of several sites at very different stages of development will be compared. These scientific data will provide a framework for developing long-term management strategies for North Carolina's barrier island system.