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- Water-Year Summary reports summarize a year of hydrologic data in a printer-friendly format.
- For water years 2014 onward, choose a water year and parameter and an on-demand Water-Year Summary report will be generated.
- For water years 2006 through 2013, choose a water year and an Annual Water Data Report will be provided.
- For water years 2005 and earlier, Annual Water Data Reports may be available in digital format.
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USGS Water-Year Summary 2024
132626144471771 EX-4 Mangilao, Guam
Other aquifers
Limestone
Limestone
LOCATION - Lat 13°26'29.7", long -144°72'4.1" referenced to North American Datum of 1983, Guam County, GM, Hydrologic Unit 22010000,
GROUNDWATER RECORDS
WELL CHARACTERISTICS - Depth 390 ft. Upper casing diameter 6 in; top of first opening undefined, bottom of last opening undefined. Drilled basal groundwater monitoring well. Well diameter 8 inches. Casing material PVC. Casing diameter 6 inches. Sounded depth of well 390 feet (2006). Drilled depth of well 400 feet.
DATUM - Land-surface datum is 153.22 ft above undefined vertical datum. Measuring point: top of pvc casing, marked, 153.61 ft above , May 29, 2008, to Sep. 16, 2015; top of pvc casing, 153.64 ft above , Sep. 17, 2015, to present.
PERIOD OF RECORD - Water-level - Occasional measurements, March 1981 to June 1991, January 1993 to May 1993, March 1995, January 1996, April 2000 to current year.
Water-Level Continuous Record--June 2010 to January 2011 as part of the Guam Groundwater Availability Study.
EXTREMES FOR PERIOD OF RECORD -
Highest discrete water level: 8.39 feet above mean sea level, December 13, 1990.
Lowest discrete water level: 4.78 feet above mean sea level, July 17, 1990.
Highest discrete water level: 8.39 feet above mean sea level, December 13, 1990.
Lowest discrete water level: 4.78 feet above mean sea level, July 17, 1990.
WATER-QUALITY RECORDS
WELL CHARACTERISTICS - Depth 390 ft. Upper casing diameter 6 in; top of first opening undefined, bottom of last opening undefined. Drilled basal groundwater monitoring well. Well diameter 8 inches. Casing material PVC. Casing diameter 6 inches. Sounded depth of well 390 feet (2006). Drilled depth of well 400 feet.
DATUM - Land-surface datum is 153.22 ft above undefined vertical datum. Measuring point: top of pvc casing, marked, 153.61 ft above , May 29, 2008, to Sep. 16, 2015; top of pvc casing, 153.64 ft above , Sep. 17, 2015, to present.
PERIOD OF RECORD - Specific-conductance profiles using a conductivity-temperature-pressure sensor (CTD): 2000 to present. Unpublished records available upon request.
Discrete-depth sampling, analysis for specific conductance and chloride concentration: 1981-1989. Unpublished records available upon request.
Fluid-resistivity profiles: 1981 to 1984. Unpublished records available upon request.
INSTRUMENTATION - Water-quality monitor with recorder set to approximately 1-second recording interval. Monitor is trolled over the total depth of the well.
REMARKS - Two specific-conductance and temperature profiles are measured during each water year; one at the end of the wet season (January) and one at the end of the dry season (June or July).
The CTD is checked against specific-conductance standards. The specific-conductance measurements in the profiles have not been adjusted based on the check measurements, however, the data are available to make adjustments.
Depth is measured using a combination of a marked and calibrated cable and pressure readings from the CTD.
