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Water-Year Summary for Site 11109520

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Available Parameters
00054 Reservoir storage(Obs.)  

Water year 2023: 2022-10-01 to 2023-09-30
 

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USGS Water-Year Summary 2023
11109520 Pyramid Lake near Gorman, CA
LOCATION - Lat 34°38'41", long 118°45'47" referenced to North American Datum of 1927, in NE 1/4 NW 1/4 sec.02, T.6 N., R.18 W., Los Angeles County, CA, Hydrologic Unit 18070102, in Angeles National Forest, in control structure near left abutment of Pyramid Dam on Piru Creek, and 11.7 mi southeast of Gorman.
DRAINAGE AREA - 295 mi².
SURFACE-WATER RECORDS
PERIOD OF RECORD - October 1988 to current year. Prior to October 1988 in files of California Department of Water Resources.
GAGE - Water-stage recorder. Datum of gage is NGVD of 1929.
COOPERATION - Records were collected by California Department of Water Resources, under general supervision of the U.S. Geological Survey, in connection with Federal Energy Regulatory Commission project no. 2426. Contents not rounded to U.S. Geological Survey standards.
REMARKS - Reservoir is formed by earth-fill dam. Storage began 1971. Dead storage below outlet to Angeles Tunnel, 5,720 acre-ft, elevation, 2,345 ft, included in contents. Capacity below invert of radial gate, 133,600 acre-ft, elevation, 2,547.72 ft; below top of radial gate, 169,901 acre-ft, elevation, 2,578 ft; below spillway level, 171,200 acre-ft, elevation, 2,579 ft. Lake receives imported water from West Branch California Aqueduct via William Warne Powerplant (station 11109398). Water is released through the Angeles Tunnel to Castaic Powerplant and during periods of low electricity demand, water from Elderberry Forebay (station 11108092) is pumped back to Pyramid Lake. Records represent total contents. See schematic diagram of Santa Clara River Basin available from the California Water Science Center.
EXTREMES FOR PERIOD OF RECORD - (at 2400 hours) Maximum contents, 171,073 acre-ft, Oct. 6, 2014, elevation, 2,578.91 ft; minimum, 137,883 acre-ft, Nov. 26, 1991, elevation, 2,551.53 ft.