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Formation of a cohesive floodplain in a dynamic experimental meandering river

Auteur(s) et Affiliation(s)

VAN DIJK, W.M.
Fac. of Geosciences, Univ., Utrecht, Pays-Bas
Fac. of Geosciences, Univ., Utrecht, Pays-Bas
KLEINHANS, M.G.
Fac. of Geosciences, Univ., Utrecht, Pays-Bas


Description :
The AA. aim to understand how different styles of floodplain formation such as overbank deposition and lateral accretion cause narrower channels and prevent chute cutoffs that lead to meandering. They present 2 experiments with a self-forming channel in identical conditions, but to one they added cohesive silt at the upstream boundary. The effect of cohesive silt on bank stability was tested in auxiliary bank erosion experiments and showed that an increase in silt reduced erosion rates by a factor of 2. The experiment without silt developed to a braided river by continuous and extensive shifting of multiple channels. In contrast, in the meandering river silt deposits increased bank stability of the cohesive floodplain and resulted in a reduction of chute cutoffs and increased sinuosity by continuous lateral migration of a single channel. Overbank flow led to deposition of the silt and 2 styles of cohesive floodplain were observed. The first style led to a reduction in bank erosion, while the second style reduced excavation of chutes. The AA. conclude that sedimentation of fine cohesive material on the floodplain by discharge exceeding bankfull is a necessary condition for meandering.


Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2013, vol. 38, n°. 13, p. 1550-1565, nombre de pages : 16, Références bibliographiques : 2 p.

Date :
2013

Editeur :
Pays édition : Royaume-Uni, Chichester, Wiley

Langue :
Anglais
Droits :
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