Delaware 2017 Coastal Inundation Maps

Delaware's Department of Natural Resources and Environmental Control (DNREC) and the scientists from Delaware Coastal Programs have developed Sea Level Rise (SLR) inundation maps for the state as an online interactive tool. The maps show the possible impacts of inundation based on various SLR scenarios for Delaware’s waterways and watersheds. The maps are a representation of inundation based on local Mean Higher High Water (MHHW), which is the long-term average of the higher of the daily high tides. Updated in 2017, the maps correspond to water surfaces from the mean higher-high water (MHHW) level to 7 feet above MHHW, in 1-foot increments. They can be viewed at a large statewide scale, detailed street level images, or focused in between, by entering an appropriate address. 

The map data are accessible through several avenues:

  1. Direct Connect to ArcGIS Map Services: The complete set of coastal inundation maps are being distributed as ArcGIS webmap services through Delaware FirstMap. The webmap services can be accessed directly from ArcGIS Desktop without the need to download the data locally to a computer first. 
  2. Online Map Viewer: This is probably the easiest and quickest way to view the maps.  The ArcGIS Online Map Viewer displays each water surface layer over a standard base map.  
  3. Data Download: The map data files, including both the ArcGIS 10.x MXD file and file geodatabase, are available from the DGS dataset collection pages.  These data must be downloaded and unzipped to a local computer and accessed through ArcGIS Desktop 10.1 or greater.  

The coast of Delaware encompasses 381 miles of shoreline, including the 24 miles that front the Atlantic Ocean, with barrier beaches, inland bays, small islands, and highly productive estuaries, marshes, and tidal flats. Potential effects from SLR include inundation of wetlands and other low-lying lands, erosion of beaches, intensified flooding, and increased salinity of rivers, bays, and groundwater tables. Storm surge becomes a threat to high-valued property located along the coast of Delaware as sea level rises as well.


Publication Date: 2017

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  • Mapping tool

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