Digital Geomorphic Mapping of the Cape Hatteras National Seashore: An Extensive Dimensional Dataset From A World-Class Barrier Island Complex

Coffey, Brian P.¹, Charles W. Hoffman¹ (1) North Carolina Geologic Survey, Raleigh, NC

Regional mapping for modern and relict geomorphic features along the Cape Hatteras National Seashore, North Carolina, USA was conducted using remote imaging. A combination of high resolution color infra-red imagery with spatial resolution of 1 meter and LiDAR data (6 m DEM's, 16 cm vertical resolution) were use to characterize onshore depositional systems over the 125 km-long, 0.4-6.4 km wide barrier island chain. The primary motivation for this study was to document the distribution of coastal barrier island landforms against which changes to this dynamic system could be compared. However, these data also can provide valuable dimensional and lateral facies relationship data from a sand-prone barrier system.

Active geomorphic feature classes mapped from this overwash-dominated island system include: beach, spit complex, fore-island dune complex, overwash complex, interior dunes, interior marsh, back-barrier berms (elevated sloping highs landward of the overwash complex), and marsh platforms. In addition, relict spit complexes and relict fore-island dune complexes were mapped on more complex island segments behind the active beach system. Companion studies involving field-based mapping of features in smaller island segments with the study area have been compared to ensure accuracy and consistency of geomorphic features remotely delineated from the remotely sensed data layers.

The compiled digital dataset will be available to the general public in GIS format. Future research will undertake similar remote mapping along the Cape Lookout National Seashore just south of the current study area, roughly doubling the size of this digital dimensional database from an extraordinary modern barrier system.