USGS Water-Year Summary 2024
421626088311401 11-SEN-I
Sand and gravel aquifers (glaciated regions)
Quaternary System
LOCATION - Lat 42°16'26.4", long 88°31'14.3" referenced to North American Datum of 1983, in SW 1/4 NW 1/4 SE 1/4 sec.22, T.44 N., R.6 E., McHenry County, IL, Hydrologic Unit 07090006, 42 feet from northwest corner of steel building, 61 feet east of Garden Valley Road, 1.3 miles north of Route 176, 0.2 miles northwest of Franklinville Creek, 0.5 miles southwest of Franklinville. and 4.8 miles northeast of Marengo. Owner: McHenry County.
REVISIONS HISTORY - Revisions: Land-surface datum was updated to 830.55 ft NAVD88 on May 30, 2023, as determined by a GNSS Level II survey. Land-surface datum was previously published as 830.63 ft NAVD88 (furnished). Discrete water-level measurements prior to May 30, 2023, are referenced to the original datum.
GROUNDWATER RECORDS
WELL CHARACTERISTICS - Depth 75.4 ft. Upper casing diameter 2 in; top of first opening 70.4 ft, bottom of last opening 74.9 ft. Well-casing includes schedule 40 PVC pipe, 8 in. diameter borehole with bentonite seal, observation well.
DATUM - Land-surface datum is 830.55 ft above North American Vertical Datum of 1988. Measuring point: Top of PVC Casing; High point marked, 2.1 ft above land-surface datum, Oct. 22, 2008 to Apr. 20, 2022; Top of PVC Casing; High point marked, 832.73 ft above land-surface datum, Oct. 22, 2008 to present; Top of PVC Casing; High point marked, 2.08 ft above land-surface datum, Apr. 20, 2022 to present.
PERIOD OF RECORD -
GROUND-WATER LEVELS: February 2009 to current.
GROUND-WATER QUALITY:
CHEMICAL: Water year 2011.
GAGE - Water level recorder and satellite telemeter.
EXTREMES FOR PERIOD OF RECORD - Highest water level, -0.12 ft below land-surface datum, July 22, 2017; lowest, 6.51 ft below land-surface datum, October 7, 8, 9, 10 and 12, 2012.