USGS Water-Year Summary for Site 02234000

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	Available Parameters
	00010 Temperature, water(Max.,Min.,Mean)
	00060 Discharge(Mean)
	00065 Gage height(Mean)
	00095 Specific cond at 25C(Max.,Min.,Mean)
	00300 Dissolved oxygen(Mean,Max.,Min.)
	63160 Stream level, NAVD88(Mean)

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

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USGS Water-Year Summary 2024

02234000 ST. JOHNS RIVER ABOVE LAKE HARNEY, NEAR GENEVA, FL

LOCATION - Lat 28°42'50", long 81°02'08" referenced to North American Datum of 1927, in NE 1/4 sec.32, T.20 S., R.33 E., Seminole County, FL, Hydrologic Unit 03080101, near center of channel on downstream side of bridge on State Highway 46, 0.9 mi downstream from Econlockhatchee River, 1 mi upstream from Lake Harney, 5.5 mi southeast of Geneva, and 190 mi upstream from mouth.

DRAINAGE AREA - 2,043 mi².

REVISIONS HISTORY - WRD FL 66-1: Drainage area;. Dissolved oxygen records for the period Dec. 4, 2017 to Feb. 21, 2018, were revised on March 15, 2018, a fouling computation error was discovered which changed the required data correction.

SURFACE-WATER RECORDS

PERIOD OF RECORD - July 1941 to September 1981 (gage heights and miscellaneous discharge measurements only). October 1981 to current year.

GAGE - Water-stage recorder, acoustic velocity meter, and data-collection platform. Datum of gage is at NGVD of 1929 (U.S. Army Corps of Engineers bench mark) and 1.30 ft below NAVD of 1988. Prior to Sept. 3, 1943, nonrecording gage, and Sept.3, 1943 to Oct. 8, 1959, water-stage recorder at site 50 ft downstream at same datum.

COOPERATION - This gage is monitored in cooperation with the St. Johns River Water Management District.

EXTREMES OUTSIDE PERIOD OF RECORD - Flood in October 1924 reached a stage of 10.1 ft, from flood mark.

WATER-QUALITY RECORDS

PERIOD OF RECORD -

SPECIFIC CONDUCTANCE: December 2007 to September 2019, July 2020 to September 2021 (discontinued).
WATER TEMPERATURE: December 2007 to September 2019, July 2020 to September 2021 (discontinued).
DISSOLVED OXYGEN: November 2010 to September 2019, July 2020 to September 2021 (discontinued).

INSTRUMENTATION - Water-quality monitor and data-collection platform.

REMARKS - Extremes for current year and extremes for period of daily record are based on recorded values and may have been exceeded during periods of no record. December 2007 to September 2008; water temperature, specific conductance, and dissolved oxygen, published as daily mean. October 2008 to September 2014; water temperature, specific conductance and dissolved oxygen published as instantaneous maximum and minimum. October 2014 to current year; water temperature, specific conductance, and dissolved oxygen published as instantaneous maximum and minimum, and daily mean. Period of record extremes updated to reflect instantaneous maximum and minimum.

EXTREMES FOR PERIOD OF RECORD -

SPECIFIC CONDUCTANCE: Maximum, 3,720 µS/cm @ 25 °C, Apr. 30, 2017; minimum, 127 µS/cm @ 25 °C, Aug. 25, 2008.

WATER TEMPERATURE: Maximum, 34.6 °C, July 27, 29, 2010; minimum, 4.6°C, Jan. 10, 11, 2010.

DISSOLVED OXYGEN: Maximum, 12.9 mg/L, May 16, 2017; minimum, 0.1 mg/L, Oct. 17, 18, 2011.