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| Titel |
Dune dynamics and roughness under gradually varying flood waves, comparing flume and field observations |
| VerfasserIn |
J. J. Warmink |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7340
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| Digitales Dokument |
URL |
| Erschienen |
In: Proceedings of river, coastal and estuarine morphodynamics ; Nr. 39 (2014-08-07), S.115-121 |
| Datensatznummer |
250121313
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| Publikation (Nr.) |
 copernicus.org/adgeo-39-115-2014.pdf |
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| Zusammenfassung |
Accurate forecasts of bed forms and their roughness during a flood wave are
essential for flood management. Bed forms remain dynamic even under steady
discharge and are subject to a continuous process of creations and
destructions of individual bed forms. Dune evolution during the rising limb
of a flood wave is quite well understood and can be modeled. However, dune
evolution during the falling limb remains poorly understood. The objective of
this paper is to explain the bed form evolution and roughness during the
receding limb of fast flood waves. Therefore, bed profiles of two flume
experiments were analyzed in detail and individual dune creations and
destructions were classified.
The results showed that for fast flood waves in subcritical water flow: (1)
dune length grows during both rising and falling limb due to amalgamation of
bed forms, (2) dune length has a longer adaptation time than dune height,
resulting in short, high dunes during the peak discharge, and (3) this
hysteresis difference between dune height and length results in a larger
roughness than predicted by equilibrium bed form dimension equations, which
may result in a larger roughness of the main channel during floods than
expected. |
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