Movement and Age of Ground Water in the Western Part of the Mojave Desert, Southern California, USA

Summary of hydrologic testing, wellbore-flow data, and expanded water-level and water-quality data, 2011–15, Fort Irwin National Training Center, San Bernardino County, California

“…In general, uncorrected 14 C ages are older than the actual age of the associated water (Izbicki and others, 1995). In this report, groundwater that had 14 C activities less than 90 pmc was interpreted as having been recharged before 1952; groundwater having 14 C activities greater than 90 pmc was interpreted as having been recharged after 1952 (Izbicki and Michel, 2003).…”

Hydrogeology and simulation of groundwater flow in the Lucerne Valley groundwater basin, California

“…Carbon-14 present in groundwater as dissolved inorganic carbon has a half-life of about 5,730 years and has been used in hydrologic studies to determine the time since recharge of older groundwater (Vogel and Ehhart, 1963). The combination of the stable and radioactive isotopes is particularly effective in arid environments for identifying sources of recharge, determining the age (time since recharge) of groundwater, and geologic controls on the movement of water (Froehlich and Yurtsever, 1995;Izbicki and Michel, 2004). Izbicki (2004) and Izbicki and Michel (2004) analyzed water samples from wells in the southeastern Mojave Desert collected between 1992 and 2000 to evaluate the mechanisms of recharge and identify the regional sources, movement, and age of groundwater.…”

“…The combination of the stable and radioactive isotopes is particularly effective in arid environments for identifying sources of recharge, determining the age (time since recharge) of groundwater, and geologic controls on the movement of water (Froehlich and Yurtsever, 1995;Izbicki and Michel, 2004). Izbicki (2004) and Izbicki and Michel (2004) analyzed water samples from wells in the southeastern Mojave Desert collected between 1992 and 2000 to evaluate the mechanisms of recharge and identify the regional sources, movement, and age of groundwater. Their research compared the geochemistry of regional precipitation and local groundwater that included samples from about 40 wells in the Lucerne Valley.…”

“…Water containing tritium, interpreted as water recharged after 1952, commonly is used as a tracer of the movement of groundwater recharged less than about 70 years before present (Izbicki and Michel, 2004). The presence of tritium can be an appropriate estimate of the initial carbon activity when carbon-14 activities are not available.…”

“…The presence of tritium can be an appropriate estimate of the initial carbon activity when carbon-14 activities are not available. Izbicki and Michel (2004) used tritium to infer carbon-14 activities in the Lucerne Valley (fig. 6A).…”