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USGS 01646500 POTOMAC RIVER NEAR WASH, DC LITTLE FALLS PUMP STA

PROVISIONAL DATA SUBJECT TO REVISION

Click to hidestation-specific text
Click for larger image LOCATION.--Lat 38°56'59.2", long 77°07'39.5", 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.
DRAINAGE AREA.--11,560 mi2.
REVISIONS HISTORY.--
  • WSP 726: Drainage area.
  • WDR MD-DE-75-1: 1973-74(M).
  • https://waterdata.usgs.gov/nwis/dv/?site_no=01646500: 2018.
  • https://waterdata.usgs.gov/nwis/uv/?site_no=01646500: 2021.
  • Discharge for Measurement 385 made on 06/25/2021 was revised on 09/22/2021 due to an error in computation.
PERIOD OF RECORD.--March 1930 to current year.
GAGE.--Water-stage recorder, crest-stage gage, and concrete control. Datum of gage is 37.20 ft above North American Vertical Datum of 1988. Prior to Jun 7, 1930, nonrecording gage, and June 7, 1930 to Jan. 22, 1965, water-stage recorder at site 1 mi upstream on right bank at same gage datum.
REMARKS.--Diversions since June 1959. U.S. Geological Survey satellite data-collection platform at station.
EXTREMES OUTSIDE PERIOD OF RECORD.--Flood of June 2, 1889, was of approximately the same magnitude as that of March 19, 1936.
COOPERATION.--Funding for the operation of this station is provided by the U.S. Geological Survey. Access to gage site provided by the Baltimore District, U.S. Army Corps of Engineers.
Boating safety tips
This station managed by the MD-DE-DC Water Science Center Baltimore office.

Available Parameters Available Period
  
2019-07-24  2026-05-28
2007-10-01  2019-10-01
2007-10-01  2019-10-01
2007-10-01  2019-10-01
2013-11-23  2019-05-27
1972-06-09  2026-05-28
2007-10-01  2026-05-28
2019-07-24  2026-05-28
2007-10-01  2019-10-01
2013-11-23  2019-05-27
2019-07-24  2026-05-28
2013-11-23  2019-05-27
2019-07-24  2026-05-28
2013-11-23  2019-05-27
2007-10-01  2026-05-28
2019-07-24  2026-05-28
2013-11-23  2019-05-27
2019-07-24  2026-05-28
2011-12-03  2019-06-11







 (7)
 
  -- or --

 

 
Summary of all available data for this site
Instantaneous-data availability statement

Temperature, water, degrees Celsius, 1.0 ft from riverbed (bottom), [Discontinued]
 
-- Data temporarily unavailable for the time period specified --

Temperature, water, degrees Celsius, 4.1 ft from riverbed (middle), [Discontinued]
 
-- Data temporarily unavailable for the time period specified --

Temperature, water, degrees Celsius, 7.1 ft from riverbed (top), [Discontinued]
 
-- Data temporarily unavailable for the time period specified --

Temperature, water, degrees Celsius, From multiparameter sonde
Most recent instantaneous value: 19.7 05-28-2026   15:50 EDT
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Temperature, water, degrees Celsius, From multiparameter sonde, [Discontinued]
 
-- Data temporarily unavailable for the time period specified --

Discharge, cubic feet per second
Most recent instantaneous value: 25500 05-28-2026   15:50 EDT
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Daily discharge, cubic feet per second -- statistics for May 28 based on 96 water years of record more
Min
(1930)		 25th
percen-
tile		 Median Mean 75th
percen-
tile		 Most Recent
Instantaneous
Value May 28		 Max
(2017)
2660 6470 9420 11500 14300 25500 37700

Gage height, feet
Most recent instantaneous value: 5.35 05-28-2026   15:50 EDT
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Specific conductance, water, unfiltered, microsiemens per centimeter at 25 degrees Celsius, 7.1 ft from riverbed (top), [Discontinued]
 
-- Data temporarily unavailable for the time period specified --

Specific conductance, water, unfiltered, microsiemens per centimeter at 25 degrees Celsius, From multiparameter sonde
Most recent instantaneous value: 214 05-28-2026   15:50 EDT
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Specific conductance, water, unfiltered, microsiemens per centimeter at 25 degrees Celsius, From multiparameter sonde, [Discontinued]
 
-- Data temporarily unavailable for the time period specified --

Dissolved oxygen, water, unfiltered, milligrams per liter, From multiparameter sonde
Most recent instantaneous value: 9.8 05-28-2026   15:50 EDT
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Dissolved oxygen, water, unfiltered, milligrams per liter, From multiparameter sonde, [Discontinued]
 
-- Data temporarily unavailable for the time period specified --

pH, water, unfiltered, field, standard units, From multiparameter sonde
Most recent instantaneous value: 7.9 05-28-2026   15:50 EDT
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pH, water, unfiltered, field, standard units, From multiparameter sonde, [Discontinued]
 
-- Data temporarily unavailable for the time period specified --

Stream water level elevation above NAVD 1988, in feet
Most recent instantaneous value: 42.39 05-28-2026   15:50 EDT
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Turbidity, water, unfiltered, monochrome near infra-red LED light, 780-900 nm, detection angle 90 +-2.5 degrees, formazin nephelometric units (FNU), From multiparameter sonde, [(2)]
Most recent instantaneous value: 32.9 05-28-2026   15:50 EDT
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Turbidity, water, unfiltered, monochrome near infra-red LED light, 780-900 nm, detection angle 90 +-2.5 degrees, formazin nephelometric units (FNU), From multiparameter sonde, [Discontinued]
 
-- Data temporarily unavailable for the time period specified --

Nitrate plus nitrite, water, in situ, milligrams per liter as nitrogen, SUNA
Most recent instantaneous value: 1.24 05-28-2026   16:30 EDT
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Nitrate plus nitrite, water, in situ, milligrams per liter as nitrogen, SUNA, [Discontinued]
 
-- Data temporarily unavailable for the time period specified --