The rising and spreading of water over normally dry land is referred to as inundation. Scientists from Delaware Coastal Programs used a simple model to develop maps to show the possible impacts of inundation based on various Sea Level Rise scenarios for Delaware’s waterways and the land that surrounds them (watersheds). These maps reflect the filling of these watersheds at constant elevations also referred to as "Bath Tub" modeling. In other words, the maps show the water levels rising in the watersheds similar to the “filling of a bathtub”.  For more information click here.
Use slider on top right to show inundation scenarios.
Use slider on left or wheel mouse to zoom in and out.
Click and drag to pan.
Shift + click and drag to draw zoom box.

Mean Higher High Water
The map illustrates the Mean Higher High Water (MHHW) which is the long-term average of the higher of the daily high tides.
0.5 m sea level rise scenario
The map illustrates the scale of potential inundation with a 0.5 meter (1.64 feet) increase to sea level rise, not the exact location, and does not account for erosion, subsidence, or future construction. Water levels are shown as they would appear during an average higher tide (Mean Higher High Water). Rising sea levels will cause daily high tides to reach farther inland.
1.0 m sea level rise scenario
The map illustrates the scale of potential inundation with a 1.0 meter (3.28 feet) increase to sea level rise, not the exact location, and does not account for erosion, subsidence, or future construction. Water levels are shown as they would appear during an average higher tide (Mean Higher High Water). Rising sea levels will cause daily high tides to reach farther inland.
1.5 m sea level rise scenario
The map illustrates the scale of potential inundation with a 1.5 meter (4.92 feet) increase to sea level rise, not the exact location, and does not account for erosion, subsidence, or future construction. Water levels are shown as they would appear during an average higher tide (Mean Higher High Water). Rising sea levels will cause daily high tides to reach farther inland.
These maps are a representation of inundation based on local Mean Higher High Water (MHHW) which is the average highest high tide line in tidal areas. Inundation is assumed to occur at a constant elevation and no other factors other than tidal elevation are used to determine water levels. The land surface elevations are based on data with an average accuracy of 15 cm (6 inches); however, areas of heavy vegetation may have errors exceeding that amount. The Delaware Coastal Programs makes no warranty and promotes no other use of these maps other than as a preliminary planning tool.
There are various uses for these maps including:
  • Assessing and planning land use and zoning ordinances to protect community resources while guiding new development
  • Developing emergency management plans to prepare for natural disasters like nor’easters or tropical storms
  • Determining impacts to the economy such as changes to the business and tourism sectors
  • Conserving wildlife, wetlands, beaches, and other natural resources
  • Protecting recreational areas like fishing spots, boating areas, parks, and cultural heritage locations
  • Developing future plans for infrastructure like roads, fire departments, schools, sewer systems, drinking water, etc
  • Managing agriculture practices to conserve working farm lands and protect irrigation sources
  • Planning for coastal community resiliency by determining hazards and vulnerabilities
Delaware Coastal Programs
89 Kings Highway
Dover, DE 19901
Phone: 302-739-9283
Fax: 302-739-2048
E-mail: Sarah.Cooksey[AT]state.de.us
Physical Location:
100 W Water Street, Suite 7B
Dover, DE 19904