ICPRB established and maintained for several years a water level monitor on the Potomac River at Edwards Ferry. In August 2011, this monitor was upgraded and is now operated and maintained by the USGS as part of their National Water Information System (NWIS). Edwards Ferry is approximately 8 miles upstream of the mouth of Little Seneca, 16 miles upstream of Great Falls, and 26 miles upstream of Little Falls. This monitor measures the water level (stage) in the river. Because higher water levels in a river are associated with higher flows, information on stage at Edwards Ferry can be used to predict river flow downstream at Little Falls, in order improve the efficiency of water supply releases from water supply reservoirs during droughts.

The stage monitor is funded by the three Washington metropolitan water suppliers including the Washington Aqueduct Division of the U.S. Army Corps of Engineers, the Washington Suburban Sanitary Commission, and Fairfax Water. The information obtained by the monitor is interpreted using data collected by gages maintained by the United States Geological Survey.

Access the Edwards Ferry real-time water level data at the USGS's NWIS website.

  • Daily Low Flow Monitoring

    Daily Low Flow Monitoring

  • September 2014 Water Supply Outlook

    September 2014 Water Supply Outlook

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    Is it safe to swim?