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Difficult Run VA
USGS Streamflow Monitor
The U.S. Geological Survey stream monitoring site on Difficult Run near Fairfax, Virginia has been collecting hydrologic data since 1935, making it one of the oldest observation points in Fairfax County. Established to support flood risk assessment and watershed management, the site has documented decades of streamflow patterns across a drainage area of 4.36 square miles. It played a key role in early studies of urbanization impacts on water quality and sediment transport, especially as the county experienced rapid development. Over time, the station has contributed to broader regional efforts, including the Chesapeake Bay Non-tidal Monitoring Network, and continues to inform environmental planning, infrastructure design, and stormwater management strategies in the Difficult Run watershed.
Federal and state agencies maintain river level monitors throughout the Potomac River Basin. The U.S.Geological Survey compiles real-time information from river monitors, in cooperation with the U.S. Army Corps of Engineers.
Current stream conditions are shown in the graph below:
For real-time data on this site, select this link.
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Contact Information
U.S. Geological Survey
1730 E Parham Rd.
Richmond VA 23228
Website