Abstract

New Protocol for NHD Coastal Watershed Revision and Updating
Track: Water Resources
Authors: James Mitchell, Sean Deinert, Kurt Johnson

Louisiana's coastal watersheds and the Mississippi River Delta are among the most dynamic landscapes on earth. This creates challenge for geospatial data development and mapping. USGS Quadrangle Maps in this area average two decades since their last revision. Some were last updated a century ago. NOAA coastline data were collected before 1940. Bathymetry often dates back to the 1800s. Existing geospatial data based on these sources are not adequate to use for maps or GIS analysis.
This presentation examines the challenges of revising the National Hydrography Dataset in coastal watersheds. The unique distinctions between coastal and "classical watersheds will be reviewed and how they led to the development of the new procedure for coastal watershed revision developed by LADOTD, for the USGS. Finally, the importance of keeping the NHD accurate and up to date will be discussed in the context of the Deepwater Horizon Oil Spill disaster.