An Investigation of Changes in Barrier Islands Using 3D Modeling
Presentation
Overview
Overview
Description
Barrier islands come in many shapes and forms depending on the geological setting and geomorphic processes. The purpose for this study was to investigate how the shape and size of one barrier island has changed through time. This investigation utilized GIS spatial analysis and 3D modeling to quantify the relationships between dune height, island width, and other morphological variables. A variety of data were gathered and compiled into a GIS for Masonboro Island, North Carolina: aerial photography, orthophotography, historical shorelines and LiDAR digital elevation models. These data were compared by: 1) delineating the boundary between back barrier marsh and upland, 2) computing cross-section elevation profiles, 3) calculating the maximum and average dune height, 4) calculating the volume of change from one time period to the next, 5) calculating the amount of deposition and erosion, and 6) calculating the distance between the shorelines and the back barrier marsh. Preliminary results have identified areas that are eroding versus accreting, experiencing overwash, and where there are large dunes versus small dunes. There are strong linear relationships between the height of the dunes and the distance between the shoreline and the marsh (R2 = 0.6) and the width of the dunes and the distance to the marsh (R2 = 0.8). Although the dune and back barrier environment changes quickly at the micro scale, overall trends in the changing topography of the island were evident. This analysis demonstrated how this undeveloped barrier island has spatially and temporally changed which provides inside for ecosystem management.
