UW Professor Publishes Groundwater Study Peering Deep into the Past

University of Wyoming Assistant Professor Kevin Befus led a groundwater study that explored how Earth’s groundwater resources contain water from the deep hydrologic past.

Befus recently joined the Department of Civil and Architectural Engineering at UW and leads the groundwater hydrology group (www.uwyo.edu/befushydro).

Befus and his collaborators calculated how much groundwater available today was replenished before the peak of the last ice age, more than 21,000 years ago, and how changing climate since then could cycle the groundwater storage. The study, titled “The rapid yet uneven turnover of Earth’s groundwater,” was published in the journal Geophysical Research Letters at http://onlinelibrary.wiley.com/doi/10.1002/2017GL073322/full.

In the report, Befus says: “The duration groundwater spends in an aquifer keeps that water from participating in the rest of the hydrologic cycle. Underground, the water can interact with the surrounding rocks and transport dissolved chemicals to and from the land surface, affecting the quality of water in wells and reaching rivers. Over geologic timescales (of thousands of years and more), these interactions transform landscapes, affect global climate, and regulate water resource sustainability and quality. Our study explores how much groundwater has recharged since the Last Glacial Maximum and where groundwater on Earth is most likely associated with previous climate conditions.”

Befus and his collaborators also contributed to a related study, led by University of Calgary hydrogeologist Scott Jasechko, that quantified how much “fossil” groundwater contributes to well water around the world and the potential for younger water to reach the wells. The research can be found at www.nature.com/articles/doi:10.1038/ngeo2943.

Fossil groundwater has been stored beneath the earth's surface for more than 12,000 years, and that ancient water is not immune to modern contamination, as has been widely assumed. Groundwater is the water stored beneath the earth's surface in soil pore spaces and within the fractures of rock formations. Groundwater provides drinking and irrigation water for billions of people around the world.

Groundwater represents about 15 percent of total water use in Wyoming and accounts for over half of the water used for public water supplies, according to a U.S. Geological Survey fact sheet, https://pubs.usgs.gov/fs/2006/3099/.

For more information about groundwater resources in Wyoming, go to www.wsgs.wyo.gov/water/groundwater; http://library.wrds.uwyo.edu/wy_gwater.html; and https://wy-mt.water.usgs.gov/projects/WY_water_use/.