NATURAL PROCESSES AND HUMAN IMPACTS: THE DYNAMIC EVOLUTION OF A COASTAL SAND DUNE COMPLEX AT JOCKEY'S RIDGE, NORTH CAROLINA

Preservation and effective management of highly dynamic coastal geomorphological features, particularly those located in areas subject to development pressures, requires an in-depth understanding of their dynamic behavior and evolution over time. Modern mapping technologies such as lidar and real-time kinematic GPS, and 3D GIS provide geospatial tools for efficient acquisition of high-resolution 3D data, and their spatial- temporal analysis. These techniques were applied to the Jockey's Ridge State Park sand dune field on the North Carolina Outer Banks, the largest active dunes on the eastern coast of the United States, with the goal of quantifying its deflation and rapid horizontal migration. In addition, historical evidence, including photos taken in the early 1900s by the Wright Brothers, nautical charts, and aerial photography were used to determine the evolution of the dune and the surrounding area over the past 90 years. A multitemporal sequence of 3D models of the dune field was used to visualize the changes in the elevation and shape of the dunes. Topographic analysis was performed to extract dune crests and slip faces and quantify horizontal dune migration. The analysis revealed rapid growth of the main dune from 1915-1949, followed by a slower rate of deflation that continues today. The deflation reduced the elevation of the main peak to half of its highest recorded value. Horizontal dune migration of 3-10 m/year has transported sand outside the park boundaries and threatened an adjacent road and several adjacent houses. As a result, the south dune section has been removed and the sand placed at the far northern end of the park to serve as a potential sand nourishment source. The analysis of topographic change has also indicated that increase in the number of visitors after the park was established in 1974 had little effect on dune deflation.