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Water: Monitoring & Assessment

Mapping Tools

  • National Hydrography Dataset (NHD) Exit EPA Disclaimer
    The National Hydrography Dataset is a comprehensive coverage of hydrographic data for the United States. It was developed by combining EPA Reach File version 3 (RF3) and the USGS Digital Line Graph (DLG) coverages. Information on previous versions of EPA Reach Files is available.

  • Watershed Assessment, Tracking and Environmental Results (WATERS)
    The WATERS information system uses EPA's standard mapping application to display water quality information about local waters. WATERS unifies information about water quality goals from EPA's Water Quality Standards Database with information about impaired waters from EPA's Total Maximum Daily Load (TMDL) Database. A PDF version of the factsheet on WATERS (2 pages, 14KB) is available.

You will need Adobe Acrobat Reader to view the Adobe PDF files on this page. See EPA's PDF page for more information about getting and using the free Acrobat Reader.

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