The effects of kinetic sorting on sediment mobility on steep slopes

Auteur(s) et Affiliation(s)



Description :
The AA. hypothesized that kinetic sorting can be an important contributor to the morphodynamics of mountain streams and attempted to demonstrate this with new flume experiments. Two long runs were produced with natural poorly sorted sediments, and with different transport stages of the coarse fraction. Both runs produced an efficient transfer downstream of the injected material, but with a major difference : the first run (no kinetic sorting) produced permanent armour figuring clusters; the second run (with kinetic sorting) also produced bed armouring, but this armour was periodically totally destroyed, leading to substantial bed erosion. The consequence is that fine materials are hidden to the flow during aggradation, allowing the slope to attain values much steeper than would have been expected at equilibrium for the mixture. However, whereas the surface armouring tends to stabilize the bed, construction of a layer of fine sediments at the subsurface also contributes to making it very unstable. These 2 contradictory effects explain the complex bed behaviours and the existence of very large bedload and slope fluctuations.


Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2014, vol. 39, n°. 8, p. 1075-1086, nombre de pages : 12, Références bibliographiques : 2 p.

Date :
2014

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