USGS Water-Year Summary 2023
395512075293701 DE 723
Piedmont and Blue Ridge crystalline-rock aquifers
Felsic Gneiss, Hornblende-Bearing
LOCATION - Lat 39°55'12.3", long 75°29'35.0" referenced to North American Datum of 1983, Delaware County, PA, Hydrologic Unit 02040202, at Glen Mills School, in Thornbury Township.
GROUNDWATER RECORDS
WELL CHARACTERISTICS - Depth 300 ft. Upper casing diameter undefined; top of first opening undefined, bottom of last opening undefined. Drilled unused observation well, casing information not available.
DATUM - Land-surface datum is 282 ft above North American Vertical Datum of 1988. Measuring point: top plywood shelf, 2.66 ft above land-surface datum, May 11, 1984 to present. Prior to May 11, 1984, top of plywood shelf 1.20 ft above land-surface datum. Elevation of land surface is from Lidar.
PERIOD OF RECORD - April 1983 to current year.
GAGE - Data collection platform with 60-minute recording interval. Satellite telemetry at station.
COOPERATION - Site maintained in cooperation with the Pennsylvania Department of Environmental Protection and the U.S. Geological Survey.
EXTREMES FOR PERIOD OF RECORD - Prior to October 2000, the extremes were based on extremes of the daily maximum depth below land-surface datum. Since that date, the extremes are based on the instantaneous depth below land-surface datum. Highest water level, 1.50 ft below land-surface datum, Dec 15, 1996; lowest, 10.25 ft below land-surface datum, Sep 26, 2002.