These polygon boundaries, inundation extents, and depth rasters were created to provide an extent of flood inundation along the Neuse River within the community of Smithfield, North Carolina. The upstream and downstream reach extent is determined by the location of high-water marks, not extending the boundary far past the outermost high-water marks. In areas of uncertainty of flood extent, the model boundary is lined up with the flood inundation polygon extent. This boundary polygon was used to extract the final flood inundation polygon and depth layer from the flood water surface raster file.
The passage of Hurricane Matthew through central and eastern North Carolina during October 7-9, 2016, brought heavy rainfall which resulted in major flooding. More than 15 inches of rain were recorded in some areas. Over 600 roads were closed including Interstates 95 and 40, and nearly 99,000 structures were impacted by floodwaters. Immediately after the flooding, the U.S. Geological Survey (USGS) documented 267 high-water marks (HWM), of which 254 were surveyed. The North Carolina Emergency Management documented and surveyed 353 HWMs. Six communities were mapped using Geographic Information Systems.