Water: Monitoring & Assessment
National Hydrography Dataset (NHD)
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.
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