USGS Water-Year Summary 2024
421533088421801 10-MAR-S
Sand and gravel aquifers (glaciated regions)
Quaternary System
LOCATION - Lat 42°15'32.5", long 88°42'19.3" referenced to North American Datum of 1983, in SW 1/4 NW 1/4 SW 1/4 sec.30, T.44 N., R.5 E., McHenry County, IL, Hydrologic Unit 07090006, about 30 ft. northeast of McHenry County Park sign and about 30 ft. north of drive in McHenry County Park, about 70 ft. east of Boone/McHenry County Line Road, 0.5 miles north of Route 20, 0.1 miles west of Rush Creek, 0.2 miles north of Kishwaukee River, and 1.1 miles northeast of Garden Prairie. Owner: McHenry County.
REVISIONS HISTORY - Revisions: Land-surface datum was updated to 780.84 ft NAVD88 on May 30, 2023, as determined by a GNSS Level II survey. Land-surface datum was previously published as 780.93 ft NAVD88 (furnished). Discrete water-level measurements prior to May 30, 2023, are referenced to the original datum.
GROUNDWATER RECORDS
WELL CHARACTERISTICS - Depth 20.3 ft. Upper casing diameter 2 in; top of first opening 15.3 ft, bottom of last opening 19.8 ft. Well-casing includes 2-inch schedule 40 PVC pipe, 6 in. diameter borehole with bentonite seal, observation well.
DATUM - Land-surface datum is 780.84 ft above North American Vertical Datum of 1988. Measuring point: Top of PVC casing; High point marked, 1.98 ft above land-surface datum, Oct. 29, 2008 to present; Top of PVC casing; High point marked, 782.91 ft above land-surface datum, Oct. 29, 2008 to present.
PERIOD OF RECORD -
GROUND-WATER LEVELS: February 2009 to current.
GROUND-WATER QUALITY:
CHEMICAL: Water year 2011.
WATER TEMPERATURE: February 2013 to March 2017.
SPECIFIC CONDUCTANCE: February 2013 to March 2017.
GAGE - Water-level recorder and satellite telemeter.
EXTREMES FOR PERIOD OF RECORD -
GROUND-WATER LEVELS: Highest water level, -0.08 ft below land-surface datum, September 4, 2018; lowest, 6.99 ft below land-surface datum, September 24-30, 2012.
WATER TEMPERATURE: Maximum, 14.0 oC, Oct. 11-20, 2016; Minimum, 6.2 oC, April 1, 3, and 14, 2015.
SPECIFIC CONDUCTANCE: Maximum, 1,450 uS/cm at 25oC, April 1-5, 7, and 8, 2015; Minimum, 653 uS/cm at 25oC, October 31, 2014.