USGS Water-Year Summary 2020
05284000 MILLE LACS LAKE AT COVE BAY NEAR ONAMIA, MN
LOCATION - Lat 46°06'36", long 93°37'08" referenced to North American Datum of 1927, in NE 1/4 NE 1/4 sec.21, T.42 N., R.26 W., Mille Lacs County, MN, Hydrologic Unit 07010207, in Minnesota Department of Natural Resources boathouse at Cove Bay boat landing, 3.6 mi northeast of Onamia.
PERIOD OF RECORD - June 1931 to current year. Month-end records for the period October 1939 to September 1953 published in WSP 1278 (fragmentary 1940-41). Published as "at Wealthwood" prior to October 1939, and as "at Garrison" October 1939 to September 1987 (gage heights collected at Wealthwood October 1939 to September 1941, but converted to gage datum at Garrison for publication). September 1987 gage established at Cove Bay boat launch, gage heights published "at Cove Bay". October 2018 gage established at mouth of Rum River, gage heights published as "at lake outlet" until current year. Gage heights converted to Cove Bay datum until surveyed into NAVD88 datum.
GAGE - Water-stage recorder. Datum of gage is 1,240.40 ft above sea level (NGVD of 1929, levels by Minnesota Department of Natural Resources). Gage readings have been converted to elevations above sea level. Prior to Oct. 1, 1941, non-recording gage at Wealthwood, 17 mi north of present site, at various datums; gage readings were converted to elevations (adjustment of 1912). Oct. 1, 1941 to Sept. 30, 1958, water-stage recorder at Garrison, 16 mi northwest of present site at datum 1,240.50 ft (adjustment of 1912). To convert these readings to NGVD of 1929, subtract 0.10 ft. Oct. 1, 1958 to Sept. 30, 1987, water-stage recorder at Garrison at present datum. Gage at Rum River lake outlet has a NAVD 1988 datum of 1240.704 ft.
EXTREMES FOR PERIOD OF RECORD - Maximum gage-height, 13.64 ft, July 21, 2002, affected by seiche action; maximum daily-mean, 13.03 ft, Aug. 22, 1972; minimum gage-height observed, 5.34 ft (present datum) Oct. 16-19, 1936.