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Titel |
Re-suspension of bed sediment in a small stream – results from two flushing experiments |
VerfasserIn |
A. Eder, M. Exner-Kittridge, P. Strauss, G. Blöschl |
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. 3 ; Nr. 18, no. 3 (2014-03-17), S.1043-1052 |
Datensatznummer |
250120306
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Publikation (Nr.) |
copernicus.org/hess-18-1043-2014.pdf |
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Zusammenfassung |
Streams draining small watersheds often exhibit multiple peaking sedigraphs
associated with single peaking hydrographs. The process reasons of the
multiple sediment peaks are not fully understood but they may be related to
the activation of different sediment sources such as the stream bed itself,
where deposited sediments from previous events may be available for
resuspension. To understand resuspension of stream bed sediments at the reach
scale we artificially flooded the small stream of the HOAL Petzenkirchen
catchment in Austria by pumping sediment-free water into the stream. Two
short floods were produced and flow, sediment and bromide concentrations were
measured at three sites with high temporal resolution. Hydrologically, the
two flood events were almost identical. The peak flows decreased from 57 to
7.9 L s−1 and the flow volumes decreased from 17 to 11.3 m2
along the 590 m reach of the stream. However, a considerably smaller
sediment load was resuspended and transported during the second flood due to
depletion of stream bed sediments. The exception was the middle section of
the stream, where more sediment was transported during the second flood event
which can be explained by differences between flow velocity and wave celerity
and the resulting displacement of sediments within the stream. The results
indicate that the first peak of the sedigraphs of natural events in this
stream is indeed caused by the resuspension of stream bed sediments,
accounting for up to six percent of the total sediment load depending on
total flow volume. |
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