USGS Water-Year Summary 2024
11528700 South Fork Trinity River below Hyampom, CA
LOCATION - Lat 40°39'00", long 123°29'35" referenced to North American Datum of 1927, in NW 1/4 SW 1/4 sec.10, T.3 N., R.6 E., Trinity County, CA, Hydrologic Unit 18010212, in Humboldt meridian, Trinity National Forest, on left bank, 0.3 mi downstream from Big Creek, 3.0 mi northwest of Hyampom, and 3.5 mi downstream from Hayfork Creek.
DRAINAGE AREA - 764 mi².
SURFACE-WATER RECORDS
PERIOD OF RECORD - October 1965 to current year.
CHEMICAL ANALYSES: Water year 1977.
WATER TEMPERATURE: Water years 1966-79, 1981-82.
SEDIMENT DATA: Water years 1967-70, 1981-82.
GAGE - Water-stage recorder and crest-stage gage. Datum of gage is 1,211.96 ft above NAVD of 1988. Oct. 1, 1965, to Aug. 24, 2000, at datum 3.00 ft higher.
EXTREMES OUTSIDE PERIOD OF RECORD - Flood of Dec. 22, 1964, reached a stage of 33.45 ft, present datum, from floodmarks, discharge, 88,000 ft³/s, on basis of flood-routing study.
EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 75,000 ft³/s, Feb. 17, 1986, gage height, 28.47 ft, present datum, from rating curve extended above 15,000 ft³/s, on basis of slope-area measurement of peak flow, maximum gage height, 31.00 ft, Jan. 26, 1983, present datum; minimum daily, 12 ft³/s, Aug. 19, 20, 2001.