A MULTI-HAZARD VULNERABILITY ASSESSMENT OF COASTAL LANDMARKS ALONG CAPE HATTERAS NATIONAL SEASHORE

Cape Hatteras National Seashore is located along the Outer Banks, a narrow string of barrier islands in eastern North Carolina. The seashore was established to preserve cultural and natural resources of national significance, yet these islands have shoreline rates of change that are predominately erosional, frequently experience storm surge inundation driven by tropical and extra-tropical storm events, and are highly vulnerable to sea level rise. The National Park Service staff are concerned about the vulnerability of historic structures located within the park, and recognized the utility of a coastal hazard risk assessment to assist park managers with long-term planning. They formed a cooperative agreement with researchers at East Carolina University to conduct the assessment, which primarily used GIS to evaluate the susceptibility of 27 historical structures to coastal erosion, storm surge, and sea-level rise. The Digital Shoreline Analysis System was used to calculate a linear regression rate of shoreline movement based on historical shorelines. Those rates were used to simulate the future position of the shoreline along transects. The SLOSH model output was down scaled to a DEM generated from the 2014 NC QL2 LiDAR collection to determine the extent and depth of inundation that would occur from storm events. Sea level rise was modeled for various scenarios referenced to existing MHHW, and also added to each SLOSH model output to determine the effect of a storm event under those sea level rise scenarios. Risk maps were developed to include not only areal coverage for existing structures and districts, but also identify potential areas of relocation or retreat in the long-term. In addition to evaluating vulnerability, timelines for potential impacts provided scenarios for National Park Service staff to research adaption and mitigation strategies.