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| Titel |
An evaluation of analytical stream to groundwater exchange models: a comparison of gross exchanges based on different spatial flow distribution assumptions |
| VerfasserIn |
M. Exner-Kittridge, J. L. Salinas, M. Zessner |
| 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. 7 ; Nr. 18, no. 7 (2014-07-29), S.2715-2734 |
| Datensatznummer |
250120418
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| Publikation (Nr.) |
 copernicus.org/hess-18-2715-2014.pdf |
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| Zusammenfassung |
| In this paper, a new method for estimating gross gains and losses
between streams and groundwater is developed and evaluated against
two existing approaches. These three stream to groundwater exchange (SGE)
estimation methods are distinct in their assumptions on the spatial
distribution of the inflowing and outflowing fluxes along the
stream. The two existing methods assume that the fluxes are
independent and in a specific sequence, while the third and newly
derived method assumes that both fluxes occur simultaneously and
uniformly throughout the stream. The analytic expressions in
connection to the underlying assumptions are investigated through numerical stream simulations to evaluate
the individual and mutual dynamics of the SGE
estimation methods and to understand the causes for the differences in
performance. The results show that the three methods produce
significantly different results and that the mean absolute
normalized error can have up to an order of magnitude difference
between the methods. These differences between the SGE
methods are entirely due to the assumptions of the SGE
spatial dynamics of the methods, and the performance for
a particular approach strongly decreases if its assumptions are not
fulfilled. The assessment of the three methods through numerical
simulations, representing a variety of SGE dynamics,
shows that the method introduced, considering simultaneous stream
gains and losses, presents overall the highest performance according to the
simulations. As the existing methods provide the minimum and maximum realistic
values of SGE within a stream reach, all three methods could
be used in conjunction for a full range of estimates. These
SGE methods can also be used in conjunction with other
end-member mixing models to acquire even more hydrologic information
as both require the same type of input data. |
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