LOCATION.--Lat 44° 04'11", long 111° 30'38"
(NAD83), in NW1/4 NE1/4 NW1/4 sec.33, T.9 N., R.42 E., Fremont
County, Lemon Lake quad., Hydrologic Unit 17040203, on left bank 0.8
mi downstream from powerplant, 3.1 mi west of Ashton, and at mile
44.2.
DRAINAGE AREA.--1,097 mi². Mean elevation, 6,710 ft.
PERIOD OF RECORD.--April 1890 to June 1891, August 1902 to June
1909, April 1920 to current year (seasonal records only 1920-26).
Monthly discharge only for some periods, published in WSP 1317.
Published as "Henrys Fork in canyon, above Fall River",
1890-91, and as "North Fork of Snake River near Ora",
1902-09. Published as station number 13046023 from 1981-92.
REVISED RECORDS.--WSP 1217: Drainage area. WSP 1347: 1890-91. WDR
ID-95-1: 1993(M). WDR-US-2010: Drainage area.
GAGE.--Elevation of gage is 5,090 ft above NGVD of 1929, from
topographic map. April 1890 to June 1891, nonrecording gage at site
5.5 mi downstream at different datum. August 1902 to Apr. 15, 1921,
nonrecording gage, and Apr. 16, 1921 to May 3, 1930, water-stage
recorder at site 1.0 mi downstream at different datum. May 3, 1930 to
Sept. 30, 1980, water-stage recorder at site 0.5 mi upstream at
different datum.
REMARKS.--Diurnal fluctuation caused by powerplant above station.
Flow regulated by Henrys Lake (see sta 13039000), Island Park
Reservoir, and by Ashton Dam, 0.8 miles upstream. Diversions above
station for irrigation of about 24,500 acres (1966
determination).
EXTREMES FOR PERIOD OF RECORD.-- UNREGULATED PERIOD (1891-1922):
Maximum discharge prior to regulation, 6,000 ft³/s May 8, 1890;
minimum daily, 910 ft³/s Feb. 4, 1906.
REGULATED PERIOD (1923 to current year): Maximum discharge since
regulation began, 8,140 ft³/s May 15, 1984, gage height, 6.50 ft;
minimum discharge, 53 ft³/s Sept. 20, 1960, gage height, 5.45 ft,
site and datum then in use; minimum daily discharge, 171 ft³/s Oct.
18, 1961.