Water, water, (not quite) everywhere

My name is Claire Goydan, and I’m a junior here at the College of William & Mary. I am studying Geology and Environmental Science. This summer, I will delve deeper in the humid swamp of Williamsburg, Virginia to better understand water, and how it moves.


As we all know, water exists in a cycle. More specifically, young fresh water is continually renewed through this cycle. On planet earth, we have enough fresh water to sustain humanity’s needs. The problem of water scarcity is not due to the volume of fresh water that exists, but rather its severe uneven spatial distribution.


This map shows the extent of water scarcity and overexploited water resources around the world.


This creates an urgent need to know more about water systems. We strive to understand hydrologic variables like flow rate, residence time, recharge rate, and groundwater age, which is the focus of my research. (Groundwater age is defined as how long ago the groundwater was precipitation; or more simply, how long it has been in the ground.)


To track groundwater age, we use tracers –  certain isotopes and gases present at known concentrations in the atmosphere. Such common tracers currently used include CFCs, 3H, and SF622Na (sodium-22) is a promising alternative to those typical tracers used today. I will test the hypothesis that 22Na provides accurate ages for groundwater along a single flow path. If we can accurately measure groundwater age, along with the other variables mentioned, we can more efficiently track and manage hydrologic systems in the future.