USGS Water-Year Summary for Site 133120144505471

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	Available Parameters
	00095 Specific cond at 25C(Max.,Min.,Mean)
	00095 Specific cond at 25C(Max.,Min.,Mean)
	00095 Specific cond at 25C(Max.,Min.,Mean)
	00095 Specific cond at 25C(Max.,Min.,Mean)
	72150 Elevation, GW, LMSL(Mean)

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Water year 2025: 2025-10-01 to 2026-09-30

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USGS Water-Year Summary 2025

133120144505471 GHURA-Dededo, Guam

Other aquifers
Limestone

LOCATION - Lat 13°31'27.3", long -144°05'9.7" referenced to North American Datum of 1983, Guam County, GM, Hydrologic Unit is unknown, at Guam International Golf Course.

GROUNDWATER RECORDS

WELL CHARACTERISTICS - Depth 785 ft. Upper casing diameter 5 in; top of first opening undefined, bottom of last opening undefined. Drilled basal groundwater monitoring well. Hole diameter 12 inches. Casing material PVC. Casing diameter 5 inches. Sounded depth 785 feet (2006). Drilled depth 785 feet.

DATUM - Land-surface datum is 394.13 ft above undefined vertical datum. Measuring point: top of pvc casing, marked, 395.87 ft above , May 18, 2004, to present.

PERIOD OF RECORD - Published USGS water-level data; 1998, 2000 to current year.

PERIOD OF DAILY RECORD - May 2004 to February 2005, and June 2010 to January 2011.

EXTREMES FOR PERIOD OF RECORD - Highest water-level measured, 4.43 feet above mean sea level, July 11, 2015; lowest water level measured, 1.0 feet above mean sea level, May 15, 2001.

WATER-QUALITY RECORDS

DATUM - Land-surface datum is 394.13 ft above undefined vertical datum. Measuring point: top of pvc casing, marked, 395.87 ft above , May 18, 2004, to present.

PERIOD OF RECORD - Specific-conductance and temperature profiles using a conductivity-temperature-pressure sensor (CTD): 2000 to present. Unpublished records available upon request. Fixed-depth specific-conductance continuous record data, May 2004 to February 2005, as part of the Northern Guam Lens Groundwater Monitoring study. Discrete-depth sampling, analysis for specific conductance and chloride concentration: 1979-1996. Unpublished records available upon request. Fluid-resistivity profiles: 1982 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 Unpublished records available upon request.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.