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| Titel |
Spatially resolved information on karst conduit flow from in-cave dye tracing |
| VerfasserIn |
U. Lauber, W. Ufrecht, N. Goldscheider |
| 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. 2 ; Nr. 18, no. 2 (2014-02-05), S.435-445 |
| Datensatznummer |
250120268
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| Publikation (Nr.) |
 copernicus.org/hess-18-435-2014.pdf |
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| Zusammenfassung |
| Artificial tracers are powerful tools for investigating karst systems. Tracers
are commonly injected into sinking streams or dolines, while springs serve
as monitoring sites. The obtained flow and transport parameters represent
mixed information from the vadose, epiphreatic and phreatic zones (that is, the
aquifer remains a black box). Accessible active caves constitute valuable but
underexploited natural laboratories to gain detailed insights into the
hydrologic functioning of the aquifer. Two multi-tracer tests in the
catchment of a major karst spring (Blautopf, Germany) with injections and
monitoring in two associated water caves aimed at obtaining spatially and
temporally resolved information on groundwater flow in different
compartments of the system. Two tracers were injected into the caves to
characterize the hydraulic connections between them and with the spring. Two
injections at the land surface, far from the spring, aimed at resolving the
aquifer's internal drainage structure. Tracer breakthrough curves were
monitored by field fluorimeters in caves and at the spring. Results
demonstrate the dendritic drainage structure of the aquifer. It was possible
to obtain relevant flow and transport parameters for different sections of
this system. The highest mean flow velocities (275 m h−1) were observed
in the near-spring epiphreatic section (open-channel flow), while velocities
in the phreatic zone (pressurized flow) were one order of magnitude lower.
Determined conduit water volumes confirm results of water balances and
hydrograph analyses. In conclusion, experiments and monitoring in caves can
deliver spatially resolved information on karst aquifer heterogeneity and
dynamics that cannot be obtained by traditional investigative methods. |
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