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Water: Monitoring & Assessment

Databases and Mapping

Water quality data and assessment results reported by states, tribes, territories and others are stored in various EPA-managed data systems. EPA and its partners, such as the U.S. Geological Survey, have also developed mapping tools to help display this information visually.

Databases | Mapping



  • 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 several EPA databases.

  • National Hydrography Dataset (NHD) Exit EPA Disclaimer - The National Hydrography Dataset is a comprehensive coverage of hydrographic data for the U.S.. It was developed by combining EPA Reach File version 3 (RF3) and the USGS Digital Line Graph (DLG) coverages.

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