For the more information about water resources in the National Park Service, please visit http://www.nature.nps.gov/water/.


Hydrographic & Impairment Statistics

Park ranger and intern taking water quality samples.
Water quality data collection in the Jamaica Bay Unit of Gateway National Recreation Area.

The Hydrographic and Impairment Statistics (HIS) database provides summary statistics of surface hydrography (acres of lakes, miles of streams, etc.) within and adjacent to each national park unit using the U.S. Geological Survey's (USGS) high resolution National Hydrography Dataset (NHD), the NPS Administrative Park Boundary Dataset, and other sources. Information regarding water impairments are supplied by state management agencies and attributed to NHD to derive impairment statistics for each national park unit. Impaired waters are identified by the State according to the federal Clean Water Act (CWA) Sections 303(d) and 305(b). Using the functionality below you can obtain an estimate of the total miles of waterway (rivers, streams, canals, etc.), acreage of waterbodies (lakes, reservoirs, ocean, etc.), number of lakes, the acreage of icemass, and much more about any national park unit or summarized across the entire National Park System. You can also see which parks contain CWA impaired hydrography, which parks have no hydrography, and which parks are 'coastal'.



Search the HIS Database

Last update: October 29, 2014

View hydrographic and impairment statistics by park, region, or network.





View park statistics in descending order by selecting a featured category.

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View impairment statistics by park for different types of impairment.

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View related park reports.





Learn how statistics were created.

Last Updated: June 30, 2014