Coastal Changes and Impacts

Delineation of Water Bodies In Emergent Wetlands

The Coastal National Elevation Database (CoNED) Applications Project team has developed new applications for pre- and post-Hurricane Sandy regional light detection and ranging (lidar) datasets for mapping the spatial extent of coastal wetlands. These new methods were developed to derive detailed land/water polygons for an area in coastal New Jersey, which is dominated by a complex configuration of emergent wetlands and open water. Using pre- and post-Hurricane Sandy lidar data, repeatable geospatial methods were used to map the land/water spatial configuration at a regional scale to complement wetland mapping that uses traditional methods such as photointerpretation and image classification.

Lidar offers high spatial resolution (< 1-meter point spacing) and precise elevation measurements that can be used to efficiently map the land/water interface. Pre- and post-Hurricane Sandy lidar data were processed and analyzed to map coastal wetland changes over the extent of the Edwin B. Forsythe National Wildlife Refuge and Barnegat Bay, New Jersey. The resulting map can be used to visualize and quantify changes in wetland morphology such as erosion, wetland inundation, internal ponding, and marsh migration across the region. The analyses are based on airborne lidar acquired in 2010 and 2014. These data provide a consistent, comprehensive wetland shoreline that is important for hydrodynamic models, for shoreline change detection analyses, and as a base layer for wetland classification maps.

For more information or to download the vector shapefiles, please visit
Forsythe_TRI_erosion Terrain roughness index spatial extent comparison of coastal wetlands in New Jersey. USGS image created by Cindy Thatcher.

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