USGS Water-Year Summary 2023
414135087521101 37N12E-16.6c3 (MF-3 Saddle)
Sand and gravel aquifers (glaciated regions)
Quaternary System
LOCATION - Lat 41°41'35.3", long 87°52'11.2" referenced to North American Datum of 1983, in SW 1/4 NE 1/4 SW 1/4 sec.16, T.37 N., R.12 E., Cook County, IL, Hydrologic Unit 07120004, groundwater well in Cook County's McMahon Fen Forest Preserve, 0.33 miles southeast of the intersection of 107th Street and Willow Springs Road, 0.38 miles north of Calumet Sag Channel, and 276 miles west of Palos Hills.
GROUNDWATER RECORDS
WELL CHARACTERISTICS - Depth 6 ft. Upper casing diameter 2 in; top of first opening 4.9 ft, bottom of last opening 5.9 ft.
DATUM - Land-surface datum is 606 ft above North American Vertical Datum of 1988. Measuring point: Top of PVC casing, north side, 3.65 ft above land-surface datum, Apr. 23, 2013 to present. Measuring point is two file marks on top north side of well casing, and is 3.65 ft above land surface.
PERIOD OF RECORD -
GROUND-WATER LEVELS: April 2013 to November 2013.
GROUND-WATER QUALITY
  WATER TEMPERATURE: April 2013 to November 2013.
  SPECIFIC CONDUCTANCE: April 2013 to November 2013.
GAGE - Water-level recorder, water-temperature and specific-conductance sensors.
EXTREMES FOR PERIOD OF RECORD -
GROUND-WATER LEVELS: Highest water level, 4.61 ft below land-surface datum, October 2-3, 2013; lowest, -0.48 ft below land-surface datum, May 29, 2013.
WATER TEMPERATURE: Maximum, 16.0oC, September 17, 2013; minimum, 6.7 oC, April 23-24, 2013.
SPECIFIC CONDUCTANCE: Maximum, 770 uS/cm at 25oC, November 26-27, 2013; minimum, 593 uS/cm at 25oC, October 30, 2013.