NGWA Event and Education Recordings Archive

You will gain insight on the use of radioisotopes to constrain estimates of groundwater age and rates of flow in this webinar, a part of the Environmental Isotopes in Groundwater Studies webinar series*.

Environmental isotopes in hydrogeology focus on the stable isotopes as tracers of groundwater recharge, mixing, and interaction with surface waters. This webinar looks at constraining the rate of circulation, or determining the age of groundwater, and looks at the use of radioisotopes to constrain estimates of groundwater age and rates of flow. For applications that involve relatively modern groundwaters, tritium and its daughter helium-3 are routinely used. Older waters can be dated with radiocarbon, and much older systems with iodine-129 and chlorine-36. The theory and application of these radioisotopes will be presented. Topics to be covered include:

     • Groundwater residence time in the recharge area
     • Tritium and helium dating of young groundwaters —
               o Background on approaches
               o Case studies
               o Sampling and analysis
     • Radiocarbon and dating old groundwaters —
               o Carbon-14 during recharge and weathering
               o Case studies for radiocarbon dating
               o Radiocarbon sampling and analysis
     • Exotic and nonroutine radioisotopes for groundwater dating.

Presentation