A flume experiment on wood storage and remobilization in braided river systems

Auteur(s) et Affiliation(s)

BERTOLDI, W.

Dept. of Civil, Environmental and Mechanical Engineering, Univ., Trento, Italie

WELBER, M.

Dept. of Civil, Environmental and Mechanical Engineering, Univ., Trento, Italie

MAO, L.

Dept. of Ecosystems and Environment, Pontifica Univ. Catolica, Santiago, Chili

ZANELLA, S.

Dept. of Civil, Environmental and Mechanical Engineering, Univ., Trento, Italie

COMITI, F.

Fac. of Science and Technology, Free Univ. of Bozen-Bolzano, Bolzano, Italie

Description :
This work investigates wood dynamics in braided streams through physical modelling in a mobile bed laboratory flume. Temporal evolution of wood deposition patterns and remobilization rates were monitored by a series of vertical images that permitted the recognition of individual logs. Results show that wood tends to disperse in generally small accumulations, with higher spatial density on top of sediment bars, and is frequently remobilized due to the intense morphological changes. The amount of wood stored in the channel depends on log input rate through a non-linear relationship, and input rates exceeding approximately 100 logs/hour determine a sharp change in wood dynamics. Turnover rates of logs were similar in the 3 flumes, independently of wood input rate and largely resembling the turnover rate of exposed bars. For the simulated conditions, significant effects of wood on bed morphology were not observed, suggesting that interactions with fine sediments and living vegetation are crucial to form large, stable wood jams able to bring about relevant morphological changes.

Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2014, vol. 39, n°. 6, p. 804-813, nombre de pages : 10, Références bibliographiques : 1 p.

Date :
2014

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

Langue :
Anglais