USGS Water-Year Summary 2025

11354500 Fall River at Fall River Mills, CA

LOCATION - Lat 41°00'27", long 121°26'49" referenced to North American Datum of 1983, in SE 1/4 SE 1/4 sec.25, T.37 N., R.4 E., Shasta County, CA, Hydrologic Unit 18020003, at center, upstream side of bridge, 0.45 mi upstream from Highway 299 bridge, and 0.50 mi northwest of Fall River Mills.

DRAINAGE AREA - 743 mi².

SURFACE-WATER RECORDS

PERIOD OF RECORD - January 1912 to August 1913, May 1921 to October 1922, October 2010 to current year.

GAGE - Water-stage recorder. Elevation of gage 3,300 ft above NGVD of 1929, from topographic map.

COOPERATION - Records were collected by Pacific Gas & Electric Co., under general supervison of the U.S. Geological Survey, in connection with Federal Regulatory Commission project no. 2687.

REMARKS - There are several irrigation diversions above gage. The largest is the McArthur canal, which diverts less than 25 ft³/s but can divert as much as 200 ft³/s and return some of this to Pit River above mouth of Fall River. In September 1922, the Mount Shasta Power Corporation began diverting water about 1.5 mi above gage for Pit No. 1 power house and in 1947, built Pit 1 Forebay. The diversion tunnel has a capacity of 1,600 ft³/s. Minimum release ranges from 50 ft³/s to 150 ft³/s seasonally. Flow is computed to 522 ft³/s up through Sep. 30, 2013. Flow is computed to 1,290 ft³/s beginning Oct. 1, 2013 through Sep. 30, 2015. Flow is computed to 1,580 ft³/s beginning Oct. 1, 2015. See schematic diagram of Pit and McCloud River Basins available from the California Water Science Center.

EXTREMES FOR PERIOD OF RECORD - Maximum discharge, 1,680 ft³/s, Mar. 31, 1922; minimum daily, 81 ft³/s, Apr. 29, 2015.