USGS Water-Year Summary 2025
404935073055901 S 33379. 1
Northern Atlantic Coastal Plain aquifer system
Lloyd Aquifer
LOCATION - Lat 40°49'32", long 73°05'59" referenced to North American Datum of 1927, Suffolk County, NY, Hydrologic Unit 02030202, at Duncan Avenue and Portion Road, in pumping center, in west recorder shelter, Lake Ronkonkoma.
GROUNDWATER RECORDS
WELL CHARACTERISTICS - Depth 1,305 ft. Upper casing diameter 4 in; top of first opening 1,290 ft, bottom of last opening 1,300 ft. Datum of gage is NGVD of 1929.
DATUM - Land-surface datum is 134 ft above National Geodetic Vertical Datum of 1929. Measuring point: Top of casing, 2.34 ft above land-surface datum, 136.34 ft above National Geodetic Vertical Datum of 1929, Mar. 5, 1970 to Mar. 31, 2016; Top of blue insert in 4" Steel well, North Side, 136.38 ft above National Geodetic Vertical Datum of 1929, Mar. 31, 2016 to Mar. 14, 2024; Top of blue insert in 4" Steel well, North Side, 136.333 ft above National Geodetic Vertical Datum of 1929, Mar. 14, 2024 to present.
PERIOD OF RECORD - October 1968 to current year. Unpublished records for October 1968 to September 1975 are available in files of the U.S. Geological Survey.
GAGE - Water-level recorder installed August 1986; 15-minute recording interval. Periodic manual measurements made by USGS personnel.
EXTREMES FOR PERIOD OF RECORD - Highest water level measured, 40.92 ft above NGVD of 1929, June 5, 1979; lowest recorded, 32.33 ft above NGVD of 1929, Oct. 3, 2017.