The presence of salt water is an important determinant of ecological communities. This dataset modifies the Northeast Terrestrial Habitat Map (linked below), developed by The Nature Conservancy, to denote the presence of salt water or brackish water as follows:
-Wetlands and waters classified by the National Wetland Inventory (http://www.fws.gov/wetlands/) as "marine", plus additional ocean waters to a distance from the coast of 10 km, are considered salt water and assigned a value of "1"
-Wetlands and waters classified by the National Wetland Inventory as "upper estuarine" are considered oligohaline and assigned a value of "0.5"
-Wetlands and waters classified by the National Wetland Inventory as "estuarine" are considered brackish and assigned a value of "0.7"
-All other areas, both terrestrial and aquatic, are assigned a value of "0"

More detailed metadata for the National Wetlands Inventory are available at: http://www.fws.gov/wetlands/Data/metadata.html

This dataset was developed as part of the Designing Sustainble Landscapes project led by Professor Kevin McGarigal of UMass Amherst and sponsored by the North Atlantic Landscape Conservation Cooperative (https://www.fws.gov/science/catalog); for more information about the entire project see: http://www.umass.edu/landeco/research/dsl/dsl.html