RAPID RESPONSE 3D SURVEY TECHNIQUES FOR SEAMLESS TOPO/BATHY MODELING: 2003 HATTERAS BREACH, NORTH CAROLINA

On 18 September 2003, Hurricane Isabel made landfall along the Outer Banks of North Carolina and created a breach in the barrier island chain south of Cape Hatteras. The breach isolated the community of Hatteras Village by washing out a 500-m section of North Carolina State Highway 12 (NC12). To rapidly assess breach geomorphology, document short-term morphological evolution, and to collect data in support of coastal modeling efforts, a series of high-density topographic and bathymetric surveys were performed. The unique three-dimensional (3D) survey design utilizes real-time kinematic GPS and ultra shallow-water singlebeam and multibeam sonar technologies. The integration of these technologies with specialized acquisition and processing techniques allows for a seamless merger of high-resolution beach and nearshore data within the surf zone. Processing the approximately 1.5 million data points into accurate 3D digital elevation models (DEMs), representing shoreline topography and nearshore bathymetry with strong anisotropy, provides a unique challenge that is handled with specialized interpolation algorithms used in both proprietary and open source GIS. Rapid 3D processing and GIS integration provided the U.S. Army Corps of Engineers (USACE) Wilmington District office with information to assess and engineer the breach closure and provided researchers of coastal processes with information that could not be adequately captured with traditional 2D techniques. Additional