USGS Water-Year Summary 2023

11475000 Eel River at Fort Seward, CA

LOCATION - Lat 40°13'06", long 123°37'53" referenced to North American Datum of 1927, in SE 1/4 NE 1/4 sec.08, T.3 S., R.5 E., Humboldt County, CA, Hydrologic Unit 18010105, Humboldt meridian, on right bank, downstream side of bridge, 1.0 mi southeast of Fort Seward, 1.9 mi upstream from Dobbyn Creek, and 11.8 mi northeast of Garberville.

DRAINAGE AREA - 2,107 mi².

REVISIONS HISTORY - May 2014 to September 2014 revised on April 13, 2016.

SURFACE-WATER RECORDS

PERIOD OF RECORD - September 1955 to current year. Prior to October 1965, published as "at Alderpoint."

GAGE - Water-stage recorder and crest-stage gage. Datum of gage is 217.26 ft above NGVD of 1929. Prior to Dec. 22, 1964, at site 7.5 mi upstream at datum 46.55 ft higher. Feb. 2, to Sept. 30, 1965, at site 7.7 mi upstream at datum 49.42 ft higher.

REMARKS - Flow slightly regulated by Lake Pillsbury (station 11470000) 99 mi upstream and by diversion through Potter Valley Powerhouse Intake (station 11471000). See schematic diagram of Eel River Basin available from the California Water Science Center.

EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 561,000 ft³/s, Dec. 22, 1964, gage height, 82.6 ft, from floodmarks, present site and datum, 87.2 ft, from floodmarks, site and datum then in use, from rating curve extended above 110,000 ft³/s, on basis of slope-area measurement at gage height 72.5 ft; minimum daily, 1.2 ft³/s, Sept. 13, 1977.

WATER-QUALITY RECORDS

PERIOD OF RECORD -

DISCRETE WATER-QUALITY DATA:
CHEMICAL ANALYSES: Water years 1972-75, 1977. 

CONTINUOUS WATER-QUALITY DATA:
WATER TEMPERATURE: Water years 1961-79.
TURBIDITY: Water years 1966-68, 1971-73.
SEDIMENT DATA: Water years 1966-79.