USGS Water-Year Summary 2021
11520500 Klamath River near Seiad Valley, CA
LOCATION - Lat 41°51'14", long 123°13'52" referenced to North American Datum of 1927, in SW 1/4 SW 1/4 sec.03, T.46 N., R.12 W., Siskiyou County, CA, Hydrologic Unit 18010206, Klamath National Forest, on left bank, 0.4 mi upstream from Bittenbender Creek, 1.4 mi downstream from Grider Creek, 2.2 mi west of Seiad Valley, and 55 mi downstream from Iron Gate Dam.
DRAINAGE AREA - 6,940 mi². approximately (not including Lost River, Butte Creek, or Lower Klamath Lake Basins).
PERIOD OF RECORD - October 1912 to September 1925, July 1951 to current year. Monthly discharges only for some periods, published in WSP 1315-B.
GAGE - Water-stage recorder and crest-stage gage. Elevation of gage is 1,320 ft above NGVD of 1929, from river-profile map. November 1912 to June 1925, nonrecording gage at site 3.5 mi upstream at different datum.
EXTREMES OUTSIDE PERIOD OF RECORD - Flood of 1927 reached a peak stage of 22 ft, from information furnished by local residents.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 165,000 ft³/s, Dec. 23, 1964, gage height, 33.75 ft, from floodmarks, from rating curve extended above 49,000 ft³/s, on basis of slope-area measurements at gage heights 20.1 and 29.2 ft; minimum daily, 320 ft³/s, Nov. 25, 1917.
PERIOD OF RECORD
DISCRETE WATER-QUALITY DATA:
CHEMICAL DATA: Water years 1959-66, 2002-03.
SEDIMENT DATA: Water years 1955-56, October 2018 to current year (storm season only).
CONTINUOUS WATER-QUALITY DATA:
DISSOLVED OXYGEN: Water years 2000-01 (daily), June 2002 to November 2003 (seasonal records only).
pH: Water years 2000-01 (daily), June 2002 to November 2003 (seasonal records only).
SPECIFIC CONDUCTANCE: Water years 2000-01 (daily), June 2002 to November 2003 (seasonal records only).
AIR TEMPERATURE: Water years 1999-2001.
WATER TEMPERATURE: Water years 1964-79, 2000-01 (daily), June 2002 to November 2003 (seasonal records only).
TURBIDITY: Water years June 2019 to current year (seasonal records only until commencement of dam removals).
INSTRUMENTATION - Water-quality monitor January, 2000 through November, 2003. Electronic data logger with 60 minute interval.