USGS Water-Year Summary 2024
04010510 GRAND PORTAGE RIVER AT GRAND PORTAGE MN
LOCATION - Lat 47°57'49", long 89°41'00" referenced to North American Datum of 1927, Cook County, MN, Hydrologic Unit 04010101,
SURFACE-WATER RECORDS
PERIOD OF RECORD - May 1991 to October 1992. October 2020 to current year.
GAGE - Water stage recorder. Datum of gage is 598.45 ft. NAVD88.
EXTREMES FOR PERIOD OF RECORD - May 1991 to October 1992: Maximum discharge 118 ft³/sec, maximum gage-height, 2.26 ft (Datum then in use), November 18, 1991. October 2020 to current year: Maximum gage-height, 19.89 ft (Backwater from Ice) April 12, 2023; Maximum discharge, undetermined (>610 ft³/sec, rating under development), Gage height. 19.62ft, May 13, 2022.
WATER-QUALITY RECORDS
PERIOD OF RECORD - Water Temperature: Oct. 2020 to current year.
INSTRUMENTATION - FTS Digitemp sensor October 21, 2020 to current year, which provides continous WT readings. Sensor is located right next to orifice end.
EXTREMES FOR PERIOD OF RECORD - WATER TEMPERATURE: Maximum, 24.8 C, July 5, 2021; minimum, <0.1 C, many days, most years.