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Water-Year Summary for Site 11446200

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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
00054 Reservoir storage(Obs.)  

Water year 2020: 2019-10-01 to 2020-09-30

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USGS Water-Year Summary 2020
11446200 Folsom Lake near Folsom, CA
LOCATION - Lat 38°42'29", long 121°09'22" referenced to North American Datum of 1927, in NW 1/4 NE 1/4 sec.24, T.10 N., R.7 E., Sacramento County, CA, Hydrologic Unit 18020111, near center of dam on American River, 0.7 mi downstream from South Fork American River, and 2.3 mi northeast of Folsom.
DRAINAGE AREA - 1,861 mi².
REVISIONS HISTORY - WSP 1931: Drainage area.
PERIOD OF RECORD - February 1955 to current year. Prior to October 1959, published as "Folsom Reservoir near Folsom."
GAGE - Water-stage recorder. Datum of gage is NGVD of 1929 (levels by U.S. Bureau of Reclamation).
COOPERATION - Records provided by U.S. Bureau of Reclamation. Total evaporation provided by U.S. Bureau of Reclamation; not reviewed by U.S. Geological Survey.
REMARKS - Records for 2014 water year were not provided. Reservoir is formed by concrete gravity-type dam with rolled-earth-wing dams, auxiliary dams, and dikes, completed May 14, 1956; storage began Feb. 25, 1955. Total capacity, 974,500 acre-ft, between elevations 205.5 ft, invert of lower tier of river outlets, and 466.0 ft, gross pool elevation, all of which are available for release. Spillway design flood pool elevation, 475.4 ft, capacity, 1,082,300 acre-ft. Records, including extremes, represent usable contents at 2400 hours. See schematic diagram of lower Sacramento River Basin available from the California Water Science Center.
EXTREMES FOR PERIOD OF RECORD - Maximum contents, 1,024,400 acre-ft, June 15, 1963, elevation, 467.23 ft; minimum since storage pool first filled, 140,600 acre-ft, Nov. 20, 21, 1977, elevation, 347.57 ft.