Geospatial analysis of vulnerable beach-foredune systems from decadal time series of lidar data

Abstract

Time series of lidar data, acquired over the past decade along the North American East Coast, provide opportunities to gain new insights into 3D evolution of barrier islands and their beach and dune systems. GIS-based per grid cell statistics and map algebra was applied to time series of Digital Surface Models representing two sections of North Carolina barrier islands to quantify elevation change trends, map dynamic and stable locations, identify new and lost buildings, measure relative volume evolution in the beach and foredune systems and analyze shoreline dynamics. Results show a relatively small stable core in both study areas, with beaches and the ocean side of the dunes exhibiting systematic high rates of elevation loss while areas landward from the dunes increase slightly in elevation. Significant number of new homes have been built at locations with very small core surface elevation, and homes built within the shoreline dynamics band have already been lost. The raster-based methodology used in this study can be applied to perform similar analyses in other coastal areas where time series of lidar data are available.

Defining Dunes: Evaluating How Dune Feature Definitions Affect Dune Interpretations from Remote Sensing

“…Although others have attempted to define foredunes generally (Hesp, 2002;Hesp and Walker, 2013), the current paper represents an attempt to define where the foredune begins (D toe ), crests (D crest ), and ends (D heel ). The following semantic models were developed for D toe , D crest , and D heel on the basis of definitions and approaches examined in this paper and similar studies (Ewing, McDonald, and Hayes, 2015;Hesp, 2002Hesp, , 2013Hesp and Walker, 2013;Mitasova et al, 2010;Mitasova, Overton, and Hardin, 2005). D toe .…”

Summary Visualizations for Coastal Spatial-Temporal Dynamics

“…We use 11 digital elevation models (DEMs) of the Outer Banks derived from LiDAR geographically registered surveys at 11 distinct time steps over the last decade. Each LiDAR data set is an (x, y, z) point cloud composed of points interpolated at a 0.5-m resolution to create a DEM [4]. U.S. Geological Survey (USGS) transects, lines perpendicular to shoreline (see Fig.…”

Lines in the Sand: Geomorphic and Geospatial Characterization and Interpretation of Sandy Shorelines and Beaches

“…Recent work evaluating changes along the beach, dunes, and back island sections along North Carolina's Outer Banks highlights the use of these new tools. One such study (Mitasova et al ) considered two areas along Hatteras Island, one north of Cape Hatteras and the other south, with an objective to evaluate and quantify beach variability and change over a study period spanning more than a decade. Results were interesting.…”