HYDROLOGY OF BIG SPRING, FAIRFIELD, UTAH: A PRELUDE TO NATIVE AMERICAN ARCHAEOLOGY

Big Spring is a groundwater-fed ecosystem located in Fairfield, Utah, 20 kilometers west of Utah Lake on the edge of the West Desert. Although there has never been any serious study or excavation, the area is rich in Native American artifacts, especially arrowheads. It is not surprising that the area was formerly occupied by Native Americans, since it is the only water source for a considerable distance. For the same reason, the area has an abundance of migrating bird species in the spring and fall. At the present time, a hydrological context is being established for this area prior to developing plans for excavations or other studies. The objectives of this particular study have been to address the following questions:

1) Does Big Spring represent a relatively permanent water source that would tend to persist even through a mega-drought (normally defined as exceeding 20 years)?

2) Where could a change in precipitation occur that would be reflected in a change in the availability of water at Big Spring?

The first objective has been addressed by using concentrations of the anthropogenic gases chlorofluorocarbon (CFC) and sulfur hexafluoride (SF₆) to determine the age of the groundwater that emerges at Big Spring, which is equivalent to the residence time in the groundwater system. The greater is this age, the more likely it is that Big Spring has represented a relatively permanent water source. The second objective is being addressed by measuring the stable isotope composition of the water from Big Spring and comparing it with the stable isotope compositions of rivers, lakes and springs throughout Utah in order to determine the likely source of the groundwater emerging at Big Spring. Analysis of water samples for CFC and SF₆ at the University of Utah Dissolved and Noble Gases Lab has shown that the groundwater age is (56 ± 4) years, which implies that Big Spring has persisted as a significant water source for both people and animals even during mega-droughts. Further results will be presented at the meeting.