USGS Water-Year Summary 2023
12322001 KOOTENAI RIVER AT PORTHILL, ID (TOTAL FLOW)
LOCATION - Lat 49°00'00", long 116°30'10" referenced to North American Datum of 1927, Boundary County, ID, Hydrologic Unit 17010104,
SURFACE-WATER RECORDS
PERIOD OF RECORD - April 1928 to current year.
EXTREMES FOR PERIOD OF RECORD - UNREGULATED PERIOD (1929-71): Maximum daily discharge prior to regulation by Libby Dam, 125,000 ft³/s June 1, 1948; maximum elevation, 1,767.61 ft, June 7, 1961; minimum daily discharge, 1,380 ft³/s Feb. 8, 1936; minimum elevation, 1,738.21 ft, Apr. 3, 1944.
REGULATED PERIOD (1972 to current year): Maximum daily discharge since regulation began, 62,700 ft³/s June 20, 2006, maximum elevation, 1,758.84 ft, June 2, 1972; minimum daily discharge, 2,610 ft³/s Jan. 9, 1973.