Understanding the interplay between permafrost conditions and groundwater flow in boreal headwater catchments, interior Alaska (USA)

Michelle Walvoord, U.S. Geological Survey, walvoord@usgs.gov (Presenter)
Clifford Voss, U.S. Geological Survey, cvoss@usgs.gov
Brian Ebel, U.S. Geological Survey, bebel@usgs.gov
Burke Minsley, U.S. Geological Survey, bminsley@usgs.gov

Permafrost distribution exerts a major control on subsurface flowpaths and fluxes of water and dissolved constituents. This study examines linkages between permafrost conditions and groundwater flow in boreal headwater catchments, where subsurface flow is primarily limited to the active layer. We use an integrated approach to assimilate findings from headwater catchment sites located along a north to south gradient in the boreal region of interior Alaska (USA) with coupled heat transfer and fluid flow modeling using the USGS SUTRA-Ice code. The study sites represent a range of shallow subsurface geology, fire history, permafrost, and air temperature conditions. Field characterization of soil hydraulic and thermal properties constrain sensitivity analyses designed to assess hillslope conditions conducive to active layer thickening and talik development and to quantify rates of change. Geophysical data, including borehole nuclear magnetic resonance (NMR) and electrical resistivity tomography (ERT), provides information relevant to permafrost conditions at the study sites and identifies areas of degrading permafrost and talik development. Model simulations reproduce temporal patterns of liquid water content as shown in the NMR data and spatial patterns of permafrost as inferred from the ERT data. Groundwater flux results highlight the impact of thaw-induced changes on baseflow and terrestrial-aquatic transport of dissolved species.

Associated Project(s): 

• Striegl-01

Poster Location ID: 53

Session Assigned: Permafrost and Hydrology