GEOMORPHIC MAPPING OF THE US NPS NATIONAL SEASHORES: A NORTH CAROLINA CASE STUDY

Geomorphic features on today’s barrier islands are complex products of their initial processes of formation, combined with modifications as they evolve through time in response to changing environmental conditions. Thus, the geomorphic features on any given barrier island are not simple or classic text book features. Rather, any feature may be characterized by extremely complex geometries with multiple spatial and temporal occurrences and/or distributions of several components. To unravel the evolutionary development and interpret the present geomorphology, an integrated approach is required that includes detailed time-slice analysis of historic aerial photography and topographic survey sequences in concert with a network of field data (including vibracores, drill cores, ground-penetrating radar, LiDAR, high-resolution seismic, and age dates). A better understanding of the geologic framework enables development of a geomorphic classification scheme and a model for barrier island evolution. The resulting geomorphic maps produced for each US NPS barrier island national seashore could become management tools that incorporate adaptation policies for the ongoing, dynamic processes associated with climate change, sea-level rise, and storms.

Critical to developing this geomorphic framework is the integration of three important factors influencing the barrier island system. 1) The impact of large storms or storm sets that drives the large-scale development of barrier island geomorphology. 2) Ecological components (including microbial flats, marshes, and maritime forests) and processes that play important roles in the evolutionary development of many geomorphic features. 3) Human activities, particularly since European colonization, that have severely modified the natural system and its geomorphic features. These three factors interact and work together to construct the present geomorphology on each barrier island. They produce the uniqueness, but also determine the complexity of each barrier island segment.