USGS Water-Year Summary 2024
421056088380801 14-RIL-S
Sand and gravel aquifers (glaciated regions)
Quaternary System
LOCATION - Lat 42°10'56.4", long 88°38'07.7" referenced to North American Datum of 1983, in NW 1/4 NW 1/4 NE 1/4 sec.27, T.43 N., R.5 E., McHenry County, IL, Hydrologic Unit 07090006, about 30 feet south of County Highway Road 31 (Harmony Road), 300 feet west of Carls Road, 0.1 miles southwest of Interstate Highway 90, 0.3 miles east of Coon Creek, and 0.6 miles south of Riley. Owner: McHenry County.
REVISIONS HISTORY - Revisions: Land-surface datum was updated to 806.46 ft NAVD88 on May 30, 2023, as determined by a GNSS Level II survey using GEOID18. Land-surface datum was previously published as 806.75 ft NAVD88. Discrete water-level measurements prior to May 30, 2023, are referenced to the original datum.
GROUNDWATER RECORDS
WELL CHARACTERISTICS - Depth 20.4 ft. Upper casing diameter 2 in; top of first opening 15.4 ft, bottom of last opening 19.9 ft. Well-casing includes schedule 40 PVC pipe, 6 in. diameter borehole with bentonite seal, observation well.
DATUM - Land-surface datum is 806.46 ft above North American Vertical Datum of 1988. Measuring point: Top of PVC casing; High point marked, 2.38 ft above land-surface datum, Oct. 30, 2008 to present; Top of PVC casing; High point marked, 809.13 ft above land-surface datum, Oct. 30, 2008 to present.
PERIOD OF RECORD -
GROUND-WATER LEVELS: February 2009 to current.
GROUND-WATER WATER QUALITY:
CHEMICAL: Water year 2011, 2012.
WATER TEMPERATURE: February 2011 to March 2017.
SPECIFIC CONDUCTANCE: February 2011 to March 2017.
GAGE - Water level recorder and satellite telemeter.
EXTREMES FOR PERIOD OF RECORD -
GROUND-WATER LEVELS: Highest water level, 3.36 ft below land-surface datum, May 23rd, 2020; lowest, 10.57 ft below land-surface datum, October 9-14, 2012.
WATER TEMPERATURE: Maximum, 13.6oC, numerous days; Minimum, 7.1oC, April 19, 2013.
SPECIFIC CONDUCTANCE: Maximum, 1610 uS/cm at 25oC, Feb 27 and 29, March 2, 2016; Minimum, 800 uS/cm at 25oC, December 9 and 10, 2011.