Can’t take the heat? Hydrogeologic responses to permafrost thaw

Sarah Evans smiling

Dr. Sarah Evans, Assistant Professor
Appalachian State University, Department of Geological and Environmental Sciences

Wednesday, April 7th, 2021

Permafrost and seasonally frozen ground are found extensively at high latitudes and intermittently at high elevation areas at lower latitudes, underlying half of the exposed land surface in the Northern Hemisphere. In these cold regions, frozen ground acts as an aquitard, impeding downward groundwater flow while simultaneously enhancing groundwater-surface water interactions. As global air temperatures increase, frozen ground degrades. Frozen ground degradation alters groundwater recharge, groundwater contribution to streamflow, and consequently, vital freshwater supplies to lowland regions. In this talk, I will employ coupled heat transfer and groundwater flow numerical models in combination with field measurements to describe the effects of warming on groundwater discharge for a suite of cold region catchments, including sites on the Qinghai-Tibet Plateau, China, and on the North Slope of Alaska.  Results highlight the difference in expected hydrologic changes for areas underlain with permafrost versus those with seasonally frozen ground and help anticipate future changes to water resources throughout the cold regions of the Northern Hemisphere.