Permafrost promotes shallow groundwater flow and warmer headwater streams
Model-data integration with international partner highlights how thawing permafrost can impact conditions of water discharged to near-by streams.
Use a fully-coupled cryohydrology model (i.e., ATS) to investigate if permafrost thaw could impact flow path depth and possibly influence the temperature of groundwater discharging from hillslopes to streams.
The ATS model simulates saturated, unsaturated, and surface flow and energy, and snow processes, for hillslope cases with various permafrost extent.
Hillslopes with continuous permafrost have more shallow flow paths than hillslopes with no permafrost.
The deeper flow paths in permafrost-free simulations buffer seasonal temperature extremes, so that summer groundwater discharge temperatures are highest with continuous permafrost.
Flow path changes will have important effects on water temperature and chemistry and potentially impact fish populations in headwater streams.
This research was supported by the Director, Office of Science, Office of Biological and Environmental Research of the US Department of Energy under Contract No. DE-AC02-05CH11231 as part of the Next-Generation Ecosystem Experiments (NGEE Arctic) project.