USGS Water-Year Summary for Site 01654500

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	Available Parameters
	00010 Temperature, water(Max.,Min.,Mean,Med.)
	00060 Discharge(Mean)
	00095 Specific cond at 25C(Max.,Min.,Mean,Med.)
	00300 Dissolved oxygen(Max.,Min.,Mean,Med.)
	00400 pH(Max.,Med.,Min.)
	63680 Turbidity, Form Neph(Mean,Max.,Min.,Med.)
	63680 Turbidity, Form Neph(Med.,Max.,Min.) [(2)]

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Water year 2024: 2024-10-01 to 2025-09-30

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USGS Water-Year Summary 2024

01654500 LONG BRANCH NEAR ANNANDALE, VA

LOCATION - Lat 38°48'48.5", long 77°14'12.3" referenced to North American Datum of 1983, Fairfax County, VA, Hydrologic Unit 02070010, on left bank, 1,080 ft upstream from State Highway 620 (Braddock Road) and 2,450 ft upstream from mouth.

DRAINAGE AREA - 3.72 mi².

SURFACE-WATER RECORDS

PERIOD OF RECORD - October 1947 to September 1956, February 2013 to current year.

GAGE - Water-stage recorder. Datum of gage is 203.4 ft NAVD of 1988. March 1947 to March 2022, gage located at several locations and at different datum.

EXTREMES FOR PERIOD OF RECORD - For period Feb. 7, 2013 to current: Maximum gage height 8.11 ft. on July 8, 2019 (gage height affected by backwater); Maximum discharge 2,520 cfs (estimated) on July 8, 2019.

WATER-QUALITY RECORDS

PERIOD OF RECORD - 1947 (annual maximum only), October 1947 to September 1956, October 1956 to September 1969 (annual maximum only), February 2013 to current year.

PERIOD OF DAILY RECORD - February 2013 to current year.

INSTRUMENTATION -

YSI EXO-3 Water-quality monitor. Electronic data logger with 15-minute recording interval.

ISCO Refridgerated sampler programmed to target events.

EXTREMES FOR PERIOD OF DAILY RECORD -
DISSOLVED OXYGEN: Maximum: 15.9 mg/L, Mar. 4, 2014, but may have been higher during periods of missing record; minimum: 4.02 mg/l on 8/10/2022.
pH: Maximum: 8.22 pH units on 4/15/2022, minimum: 6.14 pH units on 10/25/2022.
SPECIFIC CONDUCTANCE: Maximum: 8,860 microsiemens/cm, Feb. 22, 2015, but may have been higher during periods of missing record; minimum:22 uS/cm on 10/29/2021.
TURBIDITY: Maximum: 1,330 Formazin Nephelometric Units, Apr. 15, 2014, but may have been higher during periods of missing record; minimum: 0.0 FNU, on several days.
WATER TEMPERATURE: Maximum: 29.21 °C on 8/09/2022; minimum: -0.3 °C, Feb. 22, 2015.