Melt water driven stream and groundwater stage fluctuations on a glacier forefield (Dammagletscher,Switzerland) |
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| Authors: | Jan Magnusson Florian Kobierska Stephan Huxol Masaki Hayashi Tobias Jonas James W Kirchner |
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| Affiliation: | 1. WSL Institute for Snow and Avalanche Research SLF, Davos Dorf, Switzerland;2. Eawag: Swiss Federal Institute of Aquatic Science and Technology, Dübendorf, Switzerland;3. Department of Geoscience, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada;4. Swiss Federal Institute for Forest, Snow, and Landscape Research WSL, Birmensdorf, Switzerland;5. Department of Environmental Sciences, Swiss Federal Institute of Technology, ETH, Zürich, Switzerland |
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| Abstract: | In many mountain regions, large land areas with heterogeneous soils have become ice‐free with the ongoing glacier retreat. On these recently formed proglacial fields, the melt of the remaining glaciers typically drives pronounced diurnal stream level fluctuations that propagate into the riparian zone. This behaviour was measured on the Damma glacier forefield in central Switzerland with stage recorders in the stream and groundwater monitoring wells along four transects. In spite of the large groundwater stage variations, radon measurements in the near‐stream riparian zone indicate that there is little mixing between stream water and groundwater on daily time scales. At all four transects, including both losing and gaining reaches, the groundwater level fluctuations lagged the stream stage variations and were often damped with distance from the stream. Similar behaviours have been modelled using the diffusion equation in coastal regions influenced by tidal sea level variations. We thus tested the ability of such a model to predict groundwater level fluctuations in proglacial fields. The model reproduced several key features of the observed fluctuations at three of four locations, although discrepancies also arise due to non representative input data and model simplifications. Nevertheless, calibration of the model for the individual transects yielded realistic estimates of hydraulic diffusivities between the stream and groundwater monitoring wells. We conclude that studying diurnal groundwater fluctuations can provide important information about the subsurface hydrology of alpine watersheds dominated by glacier melt. Copyright © 2012 John Wiley & Sons, Ltd. |
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| Keywords: | glacier melt proglacial field stream‐groundwater interactions diurnal fluctuations diffusion model |
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