PROVISIONAL DATA SUBJECT TO REVISION

LOCATION.--Lat 42° 46'03", long 112° 52'46" (NAD83), in NE1/4 SW1/4 sec.31, 
   T.7 S., R.31 E., Power County, American Falls SW quad., Hydrologic Unit 
   17040209, on right bank 400 ft upstream from fish hatchery buildings, 
   0.9 mi downstream from American Falls Dam, and at mile 714.1. 

DRAINAGE AREA.--13,600 mi2, approximately, excluding indeterminate
   nontributary area on Snake River Plain.

PERIOD OF RECORD.--March 1906 to current year. Monthly discharge only for 
   some periods, published in WSP 1317.

REVISED RECORDS.--WSP 1317: 1910.

GAGE.--Datum of gage is 4,241.6 ft above NGVD of 1929 (levels by U.S. Bureau 
   of Reclamation). Prior to Aug. 8, 1910, nonrecording gage, and Aug. 8, 1910 
   to June 6, 1930, water-stage recorder, at site 2.5 mi downstream at different 
   datum. June 7, 1930 to Mar. 19, 1945, water-stage recorder, at site 0.4 mi 
   upstream at datum 0.4 ft higher.

REMARKS.--Flow regulated by American Falls Reservoir and other reservoirs, 
   having a combined usable capacity of 4,600,000 acre-ft. Diversions above 
   station for irrigation of about 1,080,000 acres, of which about 228,000 acres 
   are irrigated by withdrawals from ground water (1966 determination). 
   Considerable water leaks into the Snake River Plain aquifer above the station, 
   some of which returns above American Falls Reservoir. Records computed to show 
   flow at former site in sec.11, T.8 S., R.30 E., 0.5 mi north of Neeley, and 
   2.5 mi downstream from present site, by adding springs inflow between sites.

EXTREMES FOR PERIOD OF RECORD.--
   UNREGULATED PERIOD (1907-1926): Maximum discharge prior to regulation by 
   American Falls Dam, 48,400 ft3/s June 20, 1918, gage height, 13.5 ft, 
   site and datum then in use; minimum daily, 2,180 ft3/s Oct. 7, 1924.

   REGULATED PERIOD (1927 to current year): Maximum discharge since regulation 
   began, 46,100 ft3/s June 19, 24, 25, 1997, gage height, 11.46 ft; 
   minimum, 50 ft3/s, Oct. 22, 23, Nov. 14-16, 1941, Oct. 29, 1961, Nov. 6 1970; 
   minimum gage height, 0.82 ft, Oct. 29, 1961. 

Current shift-adjusted rating in tab-separated format.
These are updated daily and can change often! If you use these ratings it is important that you update often so that you have the most current version.
What is a shift-adjusted rating?

River forecasts and additional data are available at the National Weather Service Advanced Hydrologic Prediction Services web page.

Station operated in cooperation with U.S. Bureau of Reclamation.

Realtime Gage Height data is provided by U.S. Bureau of Reclamation telemetry.