A multi‐method field experiment to determine local groundwater flow in a glacier forefield |
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| Authors: | Florian Kobierska Tobias Jonas Nena Griessinger Christian Hauck Stephan Huxol Stefano M Bernasconi |
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| Institution: | 1. WSL Institute for Snow and Avalanche Research SLF, Davos, Switzerland;2. Geological Institute, ETH Zurich, Zürich, Switzerland;3. Department of Geosciences, University of Fribourg, Fribourg, Switzerland;4. EAWAG, Swiss Federal Institute of Aquatic Science and Technology, Duebendorf, Switzerland |
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| Abstract: | We implemented multiple independent field techniques to determine the direction and velocity of groundwater flow at a specific stream reach in a glacier forefield. Time‐lapse experiments were conducted using two electrical resistivity tomography (ERT) lines installed in a cross pattern. A circular array of groundwater tubes was also installed to monitor groundwater flow via discrete salt injections. Both inter‐borehole and ERT results confirmed this stream section as a losing reach and enabled quantification of the flow direction. Both techniques yielded advection velocities varying between 5.7 and 21.8 m/day. Estimates of groundwater flow direction and velocity indicated that groundwater infiltrates from the stream nearby and not from the adjacent lateral moraine. Groundwater age estimated from radon concentration measurements supported this hypothesis. Despite uncertainties inherent to each of the methods deployed, the combination of multiple field techniques allowed drawing consistent conclusions about local groundwater flow. We thus regard our multi‐method approach as a reliable way to characterize the two‐dimensional groundwater flow at sites where more invasive groundwater investigation techniques are difficult to carry out and local heterogeneities can make single measurements unreliable. Copyright © 2014 John Wiley & Sons, Ltd. |
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| Keywords: | mountain hydrology groundwater flow stream‐groundwater interactions ERT tracer experiments radon |
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