USGS Water-Year Summary 2020
01652500 FOURMILE RUN AT ALEXANDRIA, VA
LOCATION - Lat 38°50'36.0", long 77°05'09.1" referenced to North American Datum of 1983, Arlington County, VA, Hydrologic Unit 02070010, on left bank at upstream side of bridge on Shirlington Road, at Arlington County-Alexandria City line, 0.1 mi upstream from I-395, and 2.5 mi upstream from mouth.
DRAINAGE AREA - 12.6 mi².
OFR 2006-1308: Drainage area.
Revisions: Gage height and discharge for the period of July 8, 2019, were revised on May 18, 2020, based on changes to the gage height record.
Revisions: The maximum gage height for water year 2019 was revised on May 18, 2020, based on revision of the gage height record.
Revisions: The maximum discharge for water year 2019 was revised on May 18, 2020, based on revision of the gage height record.
PERIOD OF RECORD - May 1951 to current year.
GAGE - Water-stage recorder. Datum of gage is 27.66 ft. NAVD of 1988. Previous datum of gage is 28.57 ft NGVD of 1929. May 4, 1951 to Sept. 30, 1969, water stage recorder, Oct. 1, 1969 to Sept. 27, 1973, nonrecording gage, at site 0.4 mi downstream at datum of 22.55 ft NGVD of 1929 (annual maximum only). Sept. 28, 1973 to Sept. 26, 1975, water-stage recorder. Sept. 27, 1975 to Sept. 30, 1977, nonrecording gage, at present site and datum (annual maximum only). July 1979 to September 1982, water stage recorder. October 1982 to September 1998, nonrecording gage (annual maximum only). October 1998 to current year, water stage recorder.
PERIOD OF RECORD - October 2006 to current year. Unpublished records available October 2001 to September 2006 in files of the USGS.
INSTRUMENTATION - Electronic data logger with 5-minute record interval. Tipping bucket rain gage mounted on top of downstream left wingwall, about 50 ft downstream from stream gage.
EXTREMES FOR PERIOD OF RECORD - Water Years 2007 to current: Maximum daily precipitation, 4.68 in., July 28, 2017, but may have been higher during periods of missing record.