USGS Water-Year Summary for Site 11303500

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	Available Parameters
	00010 Temperature, water(Mean,Max.,Min.)
	00060 Discharge(Mean)
	63680 Turbidity, Form Neph(Max.,Med.,Min.)
	80154 Suspnd sedmnt conc(Mean)
	80155 Suspnd sedmnt disch(Mean)

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Water year 2024: 2023-10-01 to 2024-09-30

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USGS Water-Year Summary 2024

11303500 San Joaquin River near Vernalis, CA

LOCATION - Lat 37°40'34", long 121°15'55" referenced to North American Datum of 1927, San Joaquin County, CA, Hydrologic Unit 18040003, in El Pescadero Grant, on left bank, 12 ft downstream from Airport Way bridge, 2.6 mi downstream from Stanislaus River, and 3.2 mi northeast of Vernalis.

DRAINAGE AREA - 13,539 mi². includes about 2,100 mi² in James Bypass.

REVISIONS HISTORY - WSP 831: 1936. WSP 931: 1940. WSP 1930: Drainage area.

SURFACE-WATER RECORDS

PERIOD OF RECORD - July 1922 to current year (1922-23 and 1925-29, low-flow records only).

GAGE - Water-stage recorder and crest-stage gage. Datum of gage is NGVD of 1929 and 2.57 ft above NAVD of 1988. See WSP 2130 for history of changes prior to Nov. 30, 1967.

REMARKS - Natural flow of stream affected by storage reservoirs, power developments, ground-water withdrawals, and diversions for irrigation; low flows normally consist mainly of return flow from irrigated areas. See schematic diagram of Sacramento-San Joaquin Delta available from the California Water Science Center.

EXTREMES FOR PERIOD OF RECORD - Maximum discharge recorded, 79,000 ft³/s, Dec. 9, 1950, elevation, 32.81 ft, present datum, including flow through breaks in levee, maximum elevation, 34.88 ft, Jan. 5, 1997; minimum daily discharge, 30 ft³/s, Aug. 10, 1961.

WATER-QUALITY RECORDS

PERIOD OF RECORD -

DISCRETE WATER-QUALITY DATA:
CHEMICAL DATA: Water years 1951 to 1999, 2001 to current year.
BIOLOGICAL DATA: Water years 1974-81.
TURBIDITY: Water years 1972-84.
SEDIMENT DATA: Water years 1957 to current year.

CONTINUOUS WATER-QUALITY DATA:
SPECIFIC CONDUCTANCE: Water years March 1951 to May 1963, January 1973 to October 1981, June 1985 to September 2005.
WATER TEMPERATURE: Water years March 1951 to current year (water years 1951-2023, daily).
SUSPENDED-SEDIMENT DISCHARGE: Water years November 1956 to current year.
TURBIDITY: Water years September 30, 2014 to August 18, 2016.

INSTRUMENTATION - Conductivity recorder, January 1973 to October 1981, June 1985 to September 2005. Water-temperature recorder, October 1961 to September 1963, December 1972 to September 1985, October 2005 to current year. Water-quality monitor, October 1985 to September 2005. Turbidity recorder, September 2014 to October 2016.

REMARKS - Mean daily specific-conductance records, January 1973 to October 1981, provided by U.S. Bureau of Reclamation. Maximum and minimum specific-conductance values, June 1985 to September 1988, are available in files of the U.S. Geological Survey. Chemical concentration data collected by the U.S. Geological Survey National Water Quality Assessment Program (NAWQA).