USGS Water-Year Summary 2021
11530500 Klamath River near Klamath, CA
LOCATION - Lat 41°30'40", long 123°58'42" referenced to North American Datum of 1927, in SE 1/4 SE 1/4 sec.18, T.13 N., R.2 E., Del Norte County, CA, Hydrologic Unit 18010209, on right bank, 2.2 mi upstream from Turwar Creek, and 3.2 mi southeast of Klamath.
DRAINAGE AREA - 12,100 mi². approximately (not including Lost River or Lower Klamath Lake Basins).
PERIOD OF RECORD - October 1910 to December 1926 (published as "near Requa"), October 1950 to September 1994, October 1995 to September 1997 (stage only), and October 1997 to current year. Monthly discharge only for some periods, published in WSP 1315-B.
GAGE - Water-stage recorder and crest-stage gage. Datum of gage is NGVD of 1929. Prior to June 1926, nonrecording gage at same site at different datum. Oct. 1, 1950, to Oct. 2, 1975, water-stage recorder at same site at datum 5.60 ft above NGVD of 1929. Oct. 2, 1975, to Sept. 30, 2003, water-stage recorder at site 2.6 mi downstream. Relocated Sept. 30, 2003 to previous site 2.6 mi upstream, current datum.
EXTREMES OUTSIDE PERIOD OF RECORD - Flood of December 1861 reached a stage of 60 ft, site and datum then in use, discharge 450,000 ft³/s; flood of February 1881 reached a discharge of 360,000 ft³/s; flood of February 1890 reached a stage of 63 ft, site and datum then in use, discharge 425,000 ft³/s. Maximum discharges for 1927 and 1932-50, determined from upstream stations, are published in WSP 1686, Part 11, Volume 2.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 557,000 ft³/s, Dec. 23, 1964, gage height, 55.3 ft, current datum, from floodmarks, from rating curve extended above 230,000 ft³/s, on basis of flood-routing study; minimum daily, 1,310 ft³/s, Sept. 4, 1977.
PERIOD OF RECORD
DISCRETE WATER-QUALITY DATA:
CHEMICAL DATA: Water years 1951-95, 2002-03 (seasonal only).
BIOLOGICAL DATA: Water years 1975-81.
SEDIMENT DATA: Water years 1955-56, 1975-95, 2018 to current year (storm season only).
CONTINUOUS WATER-QUALITY DATA:
DISSOLVED OXYGEN: Water years 2002-04 (seasonal only).
pH: Water years 2002-04 (seasonal only).
SPECIFIC CONDUCTANCE: Water years 1975-81 (once-daily), 2002-04 (daily and seasonal only).
WATER TEMPERATURE: Water years 1966-81, 2002-03 (seasonal only), 2004 to current year (continuous 15-minute data).
TURBIDITY DATA: Water years December 8, 2019 to current year.