Delineation of Water Bodies in Emergent Wetlands in Coastal New Jersey

Hurricane Sandy, which made landfall on October 29, 2012, near Brigantine, New Jersey, had a significant impact on coastal New Jersey, including the large areas of emergent wetlands at Edwin B. Forsythe National Wildlife Refuge (NWR) and the Barnegat Bay region. In response to Hurricane Sandy, U.S. Geological Survey (USGS) has developed new applications for pre- and post-Hurricane Sandy regional lidar datasets for mapping the spatial extent of coastal wetlands. New methods have been 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 (i.e. < 1 meter point spacing) and precise elevation data 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 Forsythe NWR and Barnegat Bay. The resulting geospatial vector data can be used to visualize and quantify changes in wetland morphology such as erosion, wetland inundation, internal ponding and marsh migration across the region.