USGS Washington Water Science Center
|U.S. Department of the Interior
U.S. Geological Survey
Release: September 29, 2003
253-428-3600, ext. 2623
253-428-3600, ext. 2681
[Note: The report can be viewed on the Web at http://pubs.water.usgs.gov/wri034058/ .]
Ground water beneath the Kitsap Peninsula may be thousands of years old, according to a U.S. Geological Survey (USGS) study of the age of ground water in the area of the Navy’s base at Bangor. The study was done in cooperation with the Navy’s Engineering Field Activity Northwest, Naval Facilities Engineering Command. Estimates of ground-water age in both the shallow and deeper aquifers were used to help calibrate a USGS computer model of ground-water flow in the area of the base.
The USGS sampled water from 33 wells in the area of the base and analyzed the water for dissolved minerals, gases such as Freons, and chemical isotopes such as tritium. Freons and tritium result from human activity and are useful for age-dating the ground water. All of the samples from the shallow aquifer contained trace amounts of Freons and tritium, dating the age of the water in the tens of years old.
Scientists used carbon-14—an isotope often used to age-date ancient artifacts—to find out the age of water samples from the deeper aquifers, because the samples didn’t contain Freons or tritium.
“Looking at carbon-14 concentrations is a good way to age-date the water from the deeper aquifers,” said USGS hydrologist and report author Steve Cox. “Carbon-14 from the soil is naturally added to the ground water over time through recharge, which gives us a way to measure of the age of the water.”
In the deeper aquifers, water samples were typically several thousands of years old.
The report, “Estimates of Residence Time and Related Variations in Quality of Ground Water Beneath Submarine Base Bangor and Vicinity, Kitsap County, Washington,” by S.E. Cox, is published as U.S. Geological Survey Water-Resources Investigations Report 03-4058. The report can be viewed on the Web at http://pubs.water.usgs.gov/wri034058/. Copies can be purchased from the U.S. Geological Survey, Information Services, Box 25286, Federal Center, Denver, CO 80225-0286, telephone 303-202-4200.
The USGS serves the nation by providing reliable scientific information to describe and understand the Earth; minimize loss of life and property from natural disasters; manage water, biological, energy, and mineral resources; and enhance and protect our quality of life. To receive USGS news releases, go to https://www.usgs.gov/newsroom/list_server.asp
*** USGS ***