This dataset depicts imperviousness for the Northeastern United States. Imperviousness is the percentage of the ground surface area that is impervious to water infiltration. Development such as roads and buildings increase imperviousness, which can have large effects on both aquatic and terrestrial ecosystems.
The dataset is derived from two sources: 1) the 2006 National Land Cover Database (NLCD 2006), percent impervious product, and 2) OpenStreetMaps (www.openstreetmap.org). The NLCD 2006 was developed by the Multi-Resolution Land Cover Consortium (MRLC), which makes available metadata for the NLCD 2006 , NLCD 2001, and other information that describes how the imperviousness product was developed (http://www.mrlc.gov/). Specifically, this dataset combines NLCD 2006 imperviousness with imperviousness assigned to roads defined by OpenStreetMaps as follows: Track: 25%, Local roads: 50%, all other roads: 100%. Map units: percent.
This dataset was developed as part of the Designing Sustainable 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/nalcc/nalcc.html.