Shoreline & Tidal Marsh Inventory

Shoreline Situation Reports were developed by VIMS in the 1970s for Virginia and have been the foundation for tidal shoreline management ever since.  Now state of the art mapping and remote sensing techniques are being used to update these historic shoreline reports for Virginia and to create new inventories in other locations.  

The latest Shoreline Inventories are being generated and published entirely in digital format.   Digital Shoreline Inventories are available for coastal Virginia, Maryland, portions of Delaware, and the Chowan River Basin in North Carolina.  Tidal Marsh Inventories are sometimes included with Shoreline Inventories.  These wetland inventories map the locations and identify plant communities observed in tidal marshes. 

General Methods

Shoreline conditions that can be observed from a small boat in the field or remotely at the desktop using high resolution imagery are characterized for each shoreline inventory.   

The shorezone is divided into three regions:

  1. the upland riparian zone next to the shoreline is evaluated for land use;
  2. the bank, or transition area from upland to the water’s edge, is evaluated for height, stability, and vegetation cover; and
  3. the shoreline, is evaluated for the presence of natural buffers such as tidal marshes and beaches; shoreline structures for shore protection (revetments, bulkheads, marsh sills, groins, jetties, offshore breakwaters, etc.); and water access structures (docks, boathouses, boatramps).

Each inventory was generated using on-screen, digitizing techniques in ArcGIS while viewing conditions observed in the most recent imagery available.  The geographic extent of each inventory is first defined with a shoreline shapefile.  Three GIS shapefiles are then generated from the digitized shoreline to classify various shoreline conditions, also called attributes.  

One shapefile describes land use and bank conditions, the second reports shoreline structures that are described as arcs or lines, and the third shapefile includes all structures that are represented as points.  A metadata file is provided with the shapefiles to define attribute accuracy, data development, and any use restrictions that pertain to the inventory data. 

More details about the methods used are provided in the reports and metadata for each shoreline inventory.