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USGS Water-Year Summary 2024
11525500 Trinity River at Lewiston, CA
LOCATION - Lat 40°43'29", long 122°48'04" referenced to North American Datum of 1983, in SW 1/4 SW 1/4 sec.08, T.33 N., R.8 W., Trinity County, CA, Hydrologic Unit 18010211, on left bank, 0.47 mi downstream from Lewiston Diversion Dam, 0.8 mi upstream from Deadwood Creek, and 1.4 mi northeast of Lewiston.
DRAINAGE AREA - 719 mi².
REVISIONS HISTORY - WSP 331: 1911-12. WSP 1181: 1949. WSP 1929: Drainage area.
SURFACE-WATER RECORDS
PERIOD OF RECORD - August 1911 to current year.
CHEMICAL DATA: Water years 1951-81.
WATER TEMPERATURE: Water years 1952-55, 1958-83.
SEDIMENT DATA: Water years 1955-61, 2004-06.
CHEMICAL DATA: Water years 1951-81.
WATER TEMPERATURE: Water years 1952-55, 1958-83.
SEDIMENT DATA: Water years 1955-61, 2004-06.
GAGE - Water-stage recorder and crest-stage gage. Datum of gage is 1,821.45 ft above NAVD of 1988. See WSP 1929 for history of changes prior to July 7, 1964. July 7, 1964, to Mar. 1, 2011, at site 3,300 ft downstream at datum 14.05 ft lower.
REMARKS - Flow completely regulated by Trinity Lake (station 11525400) beginning in November 1960 and Lewiston Lake, capacity, 14,660 acre-ft, when diversion to Judge Francis Carr Powerplant (station 11525430) began in April 1963. Small diversions above head of Trinity Lake for irrigation, power, placer mining, and domestic use between Trinity Dam and station at Lewiston. See schematic diagram of Klamath River and Trinity River Basins available from the California Water Science Center.
EXTREMES OUTSIDE PERIOD OF RECORD - Flood of December 1861 reached a stage of 21.6 ft, from floodmarks 1.7 mi downstream from current site at different datum, discharge not determined.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 71,600 ft³/s, Dec. 22, 1955, gage height, 27.3 ft, from floodmarks, site and datum then in use; minimum daily, 28 ft³/s, July 30, 1924.
Since completion of Trinity Dam in 1960, maximum discharge, 14,400 ft³/s, Jan. 18, 1974, gage height, 10.41 ft, site and datum then in use, maximum gage height, 21.34 ft, Apr. 26, 2017; minimum daily, 100 ft³/s, Apr. 14, 1976.
WATER-QUALITY RECORDS
PERIOD OF RECORD - CONTINUOUS WATER-QUALITY DATA:
WATER TEMPERATURE: Water years 2020 to current year.
