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Water-Year Summary for Site 01646502

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  • Water-Year Summary reports summarize a year of hydrologic data in a printer-friendly format.
  • For water years 2014 onward, choose a water year and parameter and an on-demand Water-Year Summary report will be generated.
  • For water years 2006 through 2013, choose a water year and an Annual Water Data Report will be provided.
  • For water years 2005 and earlier, Annual Water Data Reports may be available in digital format.
  • Not all sites have reports available for every water year.
Available Parameters
00060 Discharge(Mean)  

Water year 2023: 2022-10-01 to 2023-09-30

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USGS Water-Year Summary 2023
LOCATION - Lat 38°56'59.2", long 77°07'39.5" referenced to North American Datum of 1983, Montgomery County, MD, Hydrologic Unit 02070008, on left bank just upstream from Little Falls Dam, 1 mi upstream from District of Columbia boundary line, 1.2 mi upstream from Chain Bridge, 1.8 mi east of Langley, Fairfax County, and at mile 117.4.
PERIOD OF RECORD - March 1930 to current year.
GAGE - Record includes computed discharge at 01646500 POTOMAC RIVER NEAR WASHINGTON, DC along with furnished records of diversions. Datum of gage is 37.20 ft above North American Vertical Datum of 1988.
  • Water Years 2017-2020: Records good, except those for estimated discharges, which are poor.
  • Water Years 2015-2016: Records fair, except those for estimated daily discharges, which are poor.
  • Water Year 2014: Records fair, no estimated daily discharges.
  • Water Year 2013 and prior years’ accuracy statements can be found in Annual Water Data Reports.

  • Adjusted records include diversions for municipal supply of Washington, D.C., Washington Suburban Sanitary District, city of Rockville, city of Fairfax (from Goose Creek), Fairfax County, and the Chesapeake and Ohio Canal. Furnished records provided by U.S. Army Corps of Engineers, Washington Suburban Sanitary Commission, city of Rockville, Loudoun Water, and Fairfax County Water Authority.