LOCATION.--Lat 48° 54'18", long 116° 24'07" (NAD83), in NW1/4 NE1/4 NE1/4 sec.13, T.64 N., R.1 W., Boundary County, Copeland quad., Hydrologic Unit 17010104, at the Copeland bridge, 200 ft upstream from Mission Creek, 0.7 mi northwest of Copeland, 1 mi upstream from cableway, and at mile 124.2.

DRAINAGE AREA.--13,400 mi², approximately.

PERIOD OF RECORD.--October 1927 to September 1992 (discontinued) (elevation record only prior to May 1929). Published as "at Copeland" 1927-29. April 1925 to September 1927 (gage height only) in reports of Water Survey of Canada, Department of Energy, Mines and Resources. (Gage height observations discontinued June 19, 1982.)

REVISED RECORDS.--WSP 1316: 1934-37(M), 1940-47(M), 1949(M).

GAGE.--Nonrecording gage, wire-weight gage. Datum of gage is 1,700.00 ft above Topographic Division datum of 1928. Gage readings have been reduced to that datum. National Geodetic Vertical Datum of 1929 is about 0.04 ft higher. Prior to Sept. 30, 1975, water-stage recorder located in gage shelter 1 mi downstream at same datum. October 1927 to Nov. 20, 1929, nonrecording or recording gage at site 0.2 mi downstream; datum 40.77 ft higher prior to Apr. 18, 1929.

REMARKS.--Stage-discharge relation affected by backwater from Kootenay Lake. Discharge computed from slope and conveyance of the reach between stations at Klockmann Ranch and at Porthill. The USGS BRANCH Model has been used for this computation since October 1990. Flow regulated by Libby Dam started on Mar. 21, 1972.

COOPERATION.--Station maintained by the United States under agreement with Canada. Three discharge measurements per year provided by Water Survey of Canada.

EXTREMES FOR PERIOD OF RECORD.-- UNREGULATED PERIOD (1929-71).--Maximum daily discharge, 124,000 ft/s May 30, 1948, maximum elevation, 1,772.55 ft, June 6, 1961; minimum daily discharge, 1,350 ft³/s Feb. 8, 1936; minimum elevation, 1,738.52, Apr. 2, 3, 1944. REGULATED PERIOD (1972-92).--Maximum daily discharge since regulation by Libby Dam, 56,700 ft³/s May 18, 1972; minimum daily discharge, 1,900 ft³/s Jan. 31, 1972.