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| Titel |
Residence times and mixing of water in river banks: implications for recharge and groundwater–surface water exchange |
| VerfasserIn |
N. P. Unland, I. Cartwright, D. I. Cendón, R. Chisari |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 18, no. 12 ; Nr. 18, no. 12 (2014-12-12), S.5109-5124 |
| Datensatznummer |
250120560
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| Publikation (Nr.) |
 copernicus.org/hess-18-5109-2014.pdf |
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| Zusammenfassung |
| Bank exchange processes within 50 m of the Tambo River, southeast
Australia, have been investigated through the combined use of 3H and
14C. Groundwater residence times increase towards the Tambo River,
which suggests the absence of significant bank storage.
Major ion concentrations and δ2H and δ18O
values of bank water also indicate that bank infiltration does not
significantly impact groundwater chemistry under baseflow and post-flood
conditions, suggesting that the gaining nature of the river may be driving
the return of bank storage water back into the Tambo River within days of
peak flood conditions. The covariance between 3H and 14C indicates
the leakage and mixing between old (~17 200 years)
groundwater from a semi-confined aquifer and younger groundwater (<100 years)
near the river, where confining layers are less prevalent. It is
likely that the upward infiltration of deeper groundwater from the
semi-confined aquifer during flooding limits bank infiltration. Furthermore,
the more saline deeper groundwater likely controls the geochemistry of water
in the river bank, minimising the chemical impact that bank infiltration has
in this setting. These processes, coupled with the strongly gaining nature
of the Tambo River are likely to be the factors reducing the chemical impact
of bank storage in this setting. This study illustrates the complex nature
of river groundwater interactions and the potential downfall in assuming
simple or idealised conditions when conducting hydrogeological studies. |
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