USGS Water-Year Summary 2021
06035000 WILLOW CREEK NEAR HARRISON, MT
LOCATION - Lat 45°43'23.01", long 111°44'27.69" referenced to North American Datum of 1983, in SE 1/4 SW 1/4 NW 1/4 sec.28, T.1 S., R.1 W., Madison County, MT, Hydrologic Unit 10020005, on right bank 2.2 mi upstream from Willow Creek Dam, 2.5 mi northeast of Harrison, and at river mile 13.6.
DRAINAGE AREA - 85.9 mi².
- WSP 1559: Drainage area. WDR MT-2013: Drainage area.
PERIOD OF RECORD - April 1938 to September 1982, October 1982 to October 2002, March 2004 to current year (seasonal records only). Monthly discharge only for some periods, published in Water Supply Paper (WSP) 1309.
GAGE - Water-stage recorder. Elevation of gage is 4,750 ft, referenced to the North American Vertical Datum of 1988. Apr. 22, 1938 to Oct. 8, 1946 water-stage recorder at elevation 0.22 ft higher, with different concrete control. Oct. 9, 1946 to July 31, 2014 water-stage recorder and concrete control 140 ft downstream at same datum.
EXTREMES FOR PERIOD OF RECORD - Maximum peak stage from surveyed floodmarks.
PERIOD OF DAILY RECORD - WATER TEMPERATURE (seasonal records): April 2002 to September 2002, March 2004 to current year.
INSTRUMENTATION - Water temperature probe was installed April 23, 2002.
EXTREMES FOR PERIOD OF DAILY RECORD - WATER TEMPERATURE (seasonal records): Maximum, 29.5°C, July 13 and 14, 2002 and July 6 and 18, 2007;
minimum, 0.0°C Oct. 24-27, 2002 and many days in March and April, most years.