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AGU: Geophysical Research Letters

 

Keywords

  • hyporheic exchange
  • climate change
  • arctic streams

Index Terms

  • Hydrology: Groundwater/surface water interaction
  • Global Change: Cryospheric change
  • Cryosphere: Modeling
  • Cryosphere: Permafrost
  • Cryosphere: Active layer

Abstract

Influence of morphology and permafrost dynamics on hyporheic exchange in arctic headwater streams under warming climate conditions

Jay P. Zarnetske

Department of Watershed Sciences, Utah State University, Logan, Utah, USA

Michael N. Gooseff

Department of Civil and Environmental Engineering, Pennsylvania State University, University Park, Pennsylvania, USA

W. Breck Bowden

Rubenstein School of the Environment and Natural Resources, University of Vermont, Burlington, Vermont, USA

Morgan J. Greenwald

Rubenstein School of the Environment and Natural Resources, University of Vermont, Burlington, Vermont, USA

Troy R. Brosten

Department of Geosciences, Boise State University, Boise, Idaho, USA

John H. Bradford

Department of Geosciences, Boise State University, Boise, Idaho, USA

James P. McNamara

Department of Geosciences, Boise State University, Boise, Idaho, USA

We investigated surface-subsurface (hyporheic) exchange in two morphologically distinct arctic headwater streams experiencing warming (thawing) sub-channel conditions. Empirically parameterized and calibrated groundwater flow models were used to assess the influence of sub-channel thaw on hyporheic exchange. Average thaw depths were at least two-fold greater under the higher-energy, alluvial stream than under the low-energy, peat-lined stream. Alluvial hyporheic exchange had shorter residence times and longer flowpaths that occurred across greater portions of the thawed sediments. For both reaches, the morphologic (longitudinal bed topography) and hydraulic conditions (surface and groundwater flow properties) set the potential for hyporheic flow. Simulations of deeper thaw, as predicted under a warming arctic climate, only influence hyporheic exchange until a threshold depth. This depth is primarily determined by the hydraulic head gradients imposed by the stream morphology. Therefore, arctic hyporheic exchange extent is likely to be independent of greater sub-stream thaw depths.

Received 19 September 2007; accepted 7 December 2007; published 16 January 2008.

Citation: Zarnetske, J. P., M. N. Gooseff, W. B. Bowden, M. J. Greenwald, T. R. Brosten, J. H. Bradford, and J. P. McNamara (2008), Influence of morphology and permafrost dynamics on hyporheic exchange in arctic headwater streams under warming climate conditions, Geophys. Res. Lett., 35, L02501, doi:10.1029/2007GL032049.

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