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| Titel |
Combining Radon and heat as tracers to characterise surface water and groundwater exchange pathways |
| VerfasserIn |
Gabriel C. Rau, Jonathan Frecker, Martin S. Andersen, Nicolaas P. Unland, Harald Hofmann, Ben S. Gilfedder, Alex Atkinson, Mark O. Cuthberrt, Andrew M. McCallum, Hamid Roshan, Ian Cartwright, Suzanne Hollins, Ian Acworth |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250095848
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| Publikation (Nr.) |
 EGU/EGU2014-11323.pdf |
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| Zusammenfassung |
| Heat and Radon (222-Rn) have both been used separately as natural tracers to quantify vertical streambed fluxes and to calculate water residence times in shallow alluvial systems. Both tracers have different advantages and limitations: Heat transport is measured through temperature changes at discrete spatial points in the streambed, and methods for the calculation of vertical flux time-series exist. By contrast, grab sampled Radon activities represent integration along a flow path but the discrete sampling means that only a snapshot in time can be obtained. A pumping test was conducted at Maules Creek (Australia) in order to artificially stress the stream-aquifer system. Water was continuously pumped from an extraction well located 40 m from the creek for 8 days. A flood event occurred during the pumping test adding another level of complexity to the system. The stream-aquifer response was monitored with a transect of 25 observation bores, of which 15 were regularly sampled for Radon activities. Additionally, a total of 4 temperature arrays, consisting of 4 temperature loggers each, were installed in the streambed to measure the sediment temperature over time. Vertical streambed fluxes were calculated using the temperature data. A joint interpretation of heat and Radon results reveals subsurface heterogeneity and distinct exchange pathways. This study shows the advantage of combining at least two different tracers in order to characterise a connected system. |
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