Coastal Undeveloped Habitat Blocks After 1 Meter of Sea Level Rise Map

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Data Description and Usage

This layer includes undeveloped areas of the Maine coast within 300 meters of highest annual tide following a simulated sea level rise of 1 meter (3.3 ft).

Features included in this layer depict future tidal wetlands and coastal environments as well as non-tidal buffer, and exclude current tidal area. We define future tidal wetlands in this layer as the areas between existing (current) highest annual tide (HAT0) and highest annual tide + 3.3 ft (HAT3) of sea level rise. These include (1) freshwater tidal marsh, salt marsh, and "unknown" classifications derived from MNAP mapped tidal marsh data and NWI and (2) manmade land, non-tidal buffer, rocky shoreline, and sand or gravel beach and dune future coastal environment classifications derived from MGS's Coastal Marine Geologic Environments data.

Non-tidal buffer includes areas 300m inland from the HAT3 line. All areas within 76.2m (250 ft) of impervious surface were erased using high resolution impervious data provided by the Maine Department of Inland Fisheries and Wildlife in order to further direct attention towards the future marsh and buffer areas. The non-tidal buffers were also classified using the Coastal Marine Geologic Environments where applicable.

Data Disclaimer

These data are meant to help inform decisions at the local, regional, and state-level for coastal conservation and management and sea level rise planning. Users must assume responsibility in determining the usability of this data for their purposes. Metadata is included for all of the downloadable layers and should be reviewed for more specifics on how these data were created. Neither the Maine Natural Areas Program, the Maine Geological Survey nor the Department of Agriculture, Conservation and Forestry, nor its employees or agents: (1) make any warranty, either expressed or implied for merchantability or fitness for a particular purpose, as to the accuracy or reliability of the information shown on the map; nor are they (2) liable for any damages, including consequential damages, from using the map or the inability to use the map.

Digital Data

The 1m SLR undeveloped block layer can be downloaded as a Esri File Geodatabase (ZIP 20.7MB) for use in any GIS software to perform further spatial analysis. For Esri GIS users a layer file (.lyr) is also included in the zip file.

Related Data

Tidal Marshes
Tidal Marsh Migration

Frequently Asked Questions

Do the habitat types shown represent current or future predicted habitat types?

The freshwater tidal marsh, salt marsh, sand, gravel beach, and dune habitats represent future potential habitat types and are predicted based on their adjacency to current examples of those types, and current land cover. They do not take into consideration rates of sea level rise, potential for sediment accretion or coastal erosion, or the potential for future land use conversion.

My organization is interested in conserving areas that have the potential to accommodate future marsh migration and support coastal habitats. How can the coastal undeveloped habitat block and marsh migration data help identify which areas might be the most valuable in that regard?

The marsh migration data show areas that have the potential to accommodate new tidal marsh under various scenarios of sea level rise. These can be overlayed with other resource and planning data to highlight large or contiguous areas of current and future marsh and assist with conservation or restoration planning. The Coastal Undeveloped Block data depict marsh migration under a 1 meter (3.3 foot) sea level rise scenario, along with future marsh type, and buffer zones. These can help identify places on the landscape where there is room for future tidal marsh and the buffering landscape needed to accommodate and protect functions and values of coastal habitats for water quality, floodwater storage, fisheries, recreation, and wildlife. Use the Map Viewer or download data to view mapped areas in the context of other factors such as need for public access, context in relation to other protected parcels, local need for ecosystem services such as floodwater storage and water quality, and opportunity.

Does non-tidal buffer include land that is currently managed for agriculture?

Yes. The non-tidal buffer only excludes impervious surface areas (and a 250' zone of influence from those impervious surface areas).

More Help

Contact the Maine Natural Areas Program at

Updated: 10/4/2016