Durham Neighborhood CompassDurham Neighborhood Compass

Why This is Important

Impervious surfaces, including paved areas such as roads, parking lots, and sidewalks as well as rooftops, prevent water from draining naturally into the ground. The results are many, including an increased burden on stormwater infrastructure, erosion, reduced water quality, 'heat island effects', and both ground-level and water pollution. To learn more about the impacts of concentrated impervious areas see the EPA fact sheet linked below.

About the Data

This measurement is derived from the National Land Cover Database (NLCD) 30-meter national dataset. It represents the percent of total land within each block group that is impervious and not covered by tree canopy.

NOTE: Prior to June 2020, the Compass relied on National Agricultural Imagery Program (NAIP) data sourced from the EPA EnviroAtlas. This information reported only on the urbanized area of Durham County, and gave metric estimates which were slightly larger than the current compass values (an 8.1% larger value than the NLCD estimates on average). We switched to NLCD data in order to both extend the time series reported here - showing information for both earlier and more recent years - and to extend the area of coverage to the entire county. Comparisons to all areas of the contiguous US are also made possible by choosing NLCD for these summaries.

Source: National Land Cover Database (NLCD), accessed via the Multi-Resolution Land Characteristics Consortium.

Additional Resources

ResourceLearn More and Take Action
Multi-Resolution Land Characteristics Consortium (MRLC)The MRLC is a long-standing consortium of federal agencies which provides geospatial data describing land cover characteristics across the United States.
EnviroAtlas GlossaryTerms and definitions used throughout the EnviroAtlas website, fact sheets, and other resources.
Why Is Percent Impervious Area Important?A factsheet from the Environmental Protection Agency (EPA).
Census TractsCensus Blockgroups

Select a base geography (depending on the dataset, different geographies may be available).

Or, select a, or

Data Distribution, 2019

Impervious Area

Share feedback or questions