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| Titel |
Bank erosion events and processes in the Upper Severn basin |
| VerfasserIn |
D. M. Lawler, J. Couperthwaite, L. J. Bull, N. M. Harris |
| 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 ; 1, no. 3 ; Nr. 1, no. 3, S.523-534 |
| Datensatznummer |
250000195
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| Publikation (Nr.) |
 copernicus.org/hess-1-523-1997.pdf |
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| Zusammenfassung |
This paper examines river bank retreat rates, individual erosion
events, and the processes that drive them in the Upper Severn basin, mid-Wales, UK. Traditional
erosion
pin networks were used to deliver information on patterns of downstream change in erosion
rates. In addition, the novel automatic Photo-Electronic Erosion Pin (PEEP) monitoring system
was deployed to generate near-continuous data on the temporal distribution of bank
erosion and accretion: this allowed focus on the magnitude and timing of individual erosional and
depositional events in relation to specific flow episodes. Erosion dynamics data from throughout
the Upper Severn basin are combined with detailed information on bank material properties
and spatial change in channel hydraulics derived from direct field survey, to assess the
relationships between flow properties and bank erosion rates.
Results show that bank erosion rates generally increase
downstream, but relate more strongly to discharge than to reach-mean shear stress, which peaks near the basin
head. Downstream changes in erosion mechanisms and boundary materials, across the upland/lowland
transition (especially the degree of development of composite bank material profiles),
are especially significant. Examples of sequences of bank erosion events show how
the PEEP system can (a) quantify the impact of individual, rather than aggregated, forcing
events, (b) reveal the full complexity of bank response to given driving agents, including delayed
erosion events, and (c) establish hypotheses of process-control in bank erosion systems. These
findings have important implications for the way in which bank erosion problems are researched
and managed. The complex responses demonstrated have special significance for the way
in which bank processes and channel-margin sediment injections should be handled in river dynamics
models. |
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