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Water-Year Summary for Site USGS 11264500

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  • Water-Year Summary reports summarize a year of hydrologic data in a printer-friendly format.
  • For water years 2014 onward, choose a water year and parameter and an on-demand Water-Year Summary report will be generated.
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Available Parameters
00010 Temperature, water(Mean,Max.,Min.)  
00060 Discharge(Mean)  

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

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USGS Water-Year Summary 2023
11264500 Merced River at Happy Isles Bridge, near Yosemite, CA
LOCATION - Lat 37°43'53", long 119°33'29" referenced to North American Datum of 1927, Mariposa County, CA, Hydrologic Unit 18040008, unsurveyed, in Yosemite National Park, on left bank, 30 ft upstream from remnants of footbridge at Happy Isles, 0.4 mi downstream from Illilouette Creek, and 2.0 mi southeast of Yosemite National Park Headquarters.
DRAINAGE AREA - 181 mi².
REVISIONS HISTORY - WSP 1215: 1938 (instantaneous maximum discharge).
PERIOD OF RECORD - August 1915 to current year.
GAGE - Water-stage recorder. Elevation of gage is 4,030 ft above NGVD of 1929, from topographic map.  Prior to November 17, 2010 elevation of gage is 4,016.58 ft above NGVD of 1929. Prior to Nov. 2, 1916, nonrecording gage at datum 0.55 ft lower.
REMARKS - Up to 5 ft³/s can be diverted upstream from station.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 10,100 ft³/s, Jan. 2, 1997, gage height, 13.27 ft, from rating curve extended above 4,000 ft³/s, on basis of contracted-opening measurements at gage heights 10.4 and 11.55 ft; minimum daily, 1.5 ft³/s, Sept. 26, 1977.

CHEMICAL DATA: Water years 1968-96, 2001-03.
BIOLOGICAL DATA: Water years 1973-81.
SEDIMENT DATA: Water years 1970-71, 1973-96, 2001-03.

WATER TEMPERATURE: Water years October 1965 to September 1977, October 1978 to September 1993, March 2012 to current year.

INSTRUMENTATION - Temperature recorder water years 1966-77, 1979-93, and since March 2012.
REMARKS - The practice of rating water quality records was discontinued in the 2017 water year.