USGS Water-Year Summary 2024
422120088330901 MARN-09-01
Sand and gravel aquifers (glaciated regions)
Quaternary System
LOCATION - Lat 42°21'20.02", long 88°33'08.52" referenced to North American Datum of 1983, in NE 1/4 NE 1/4 NE 1/4 sec.29, T.45 N., R.6 E., McHenry County, IL, Hydrologic Unit 07090006, 76 feet northwest of end of access road to McHenry County Brookdale Conservation Area, 220 feet northeast of Route 14, 0.1 mile west of Paulson Road, 0.15 miles east of North Branch Kishwaukee River, 5.6 miles southeast of Harvard and 6.0 miles northwest of Woodstock. Owner: Illinois State Geological Survey.
REVISIONS HISTORY - Revisions: Land-surface datum was updated to 909.98 ft NAVD88 on May 30, 2023, as determined by a GNSS Level II survey. Land-surface datum was previously published as 909 ft NAVD88 from LiDAR (furnished). Discrete water-level measurements prior to May 30, 2023, are referenced to the original datum.
GROUNDWATER RECORDS
WELL CHARACTERISTICS - Depth 100.7 ft. Upper casing diameter undefined; top of first opening 95.4 ft, bottom of last opening 100.4 ft. Well-casing includes 2-inch schedule 40 PVC pipe, 5.5 in. diameter borehole sealed with benseal grout, observation well.
DATUM - Land-surface datum is 909.98 ft above North American Vertical Datum of 1988. Measuring point: File mark on top southeast side of PVC well casing, 3.21 ft above land-surface datum, Jul. 31, 2009 to present.
PERIOD OF RECORD -
GROUND-WATER LEVELS: September 2009 to current. Prior to September 2009,
observation well readings available from the Illinois State Geological Survey.
GROUND-WATER QUALITY:
CHEMICAL: Water year 2011.
GAGE - Water level recorder and satellite telemeter.
EXTREMES FOR PERIOD OF RECORD - Highest water level, 28.42 ft below land-surface datum, June 1, 2019; lowest, 38.10 ft below land-surface datum, December 5, 2012.