LOCATION.--Lat 48° 37'04", long 116° 02'47", in
NW1/4 NW1/4 NW1/4 sec.20, T.33 N., R.34 W., principal Meridian,
Lincoln County, Montana, Leonia quad, Hydrologic Unit 17010104, on
right bank at Leonia, 450 ft east of Montana-Idaho State line, 0.5 mi
upstream from Boulder Creek, and at mile 171.6.
DRAINAGE AREA.--11,740 mi², approximately.
PERIOD OF RECORD.--March 1928 to current year.
GAGE.--Water-stage recorder. Datum of gage is 1,790.25 ft above
NGVD of 1929 or converted to NAVD 88 is 1794.118 ft. Prior to Oct. 1,
1970, at datum 90 ft lower. Prior to Nov. 13, 1928, nonrecording gage
on bridge 250 ft upstream at datum 90.41 ft lower.
REMARKS.--Diversions above station for irrigation of about 14,600
acres. Flow regulated by Libby Dam and power plant since Mar. 21,
1972.
EXTREMES FOR PERIOD OF RECORD.-- UNREGULATED PERIOD (1929-71):
Maximum discharge prior to regulation by Libby Dam, and powerplant,
123,000 ft³/s May 28, 1948, gage height, 33.40 ft; minimum, 996 ft³/s
Dec. 9, 1936, minimum gage height, 7.56 ft, Dec. 10, 1929.
REGULATED PERIOD (1972 to current year): Maximum discharge since
regulation began, 62,000 ft³/s Jan. 16, 1974, gage height, 24.15 ft;
maximum gage height, 25.87 ft, June 17, 18, 2006; minimum daily
discharge, 2,270 ft Dec. 9, 1972.
EXTREMES OUTSIDE PERIOD OF RECORD.--Floods of June 1894 and 1916
reached stages of 34.6 and 31.6 ft, respectively, present datum, from
information by Great Northern Railway.
May 22, 2013 15:45 EDT: Notice:
The outage of the GOES-13 East satellite that occurred earlier today, which kept USGS Water Data current condition data from being updated, is largely over. Only a few dozen sites, mostly east of the Mississippi River, are still affected.
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