Scale-dependent controls upon the fluvial export of large wood from river catchments

Auteur(s) et Affiliation(s)



Description :
The annual fluvial export of large wood (LW) was monitored by local reservoir management offices in Japan. LW export per unit watershed area was relatively high in small watersheds, peaked in intermediate watersheds, and decreased in large watersheds. To explain these variations, the AA. surveyed the amount of LW with respect to channel morphology in 78 segments in the Nukabira River, northern Japan. They examined the differences in LW dynamics, including its recruitment, transport, storage, and fragmentation and decay along the spectrum of watershed sizes. The AA. found that a large proportion of LW produced by forest dynamics and hillslope processes was retained because of the narrower valley floors and lower stream power in small watersheds. Although these stored LW pieces can be refloated and transported by subsequent flood events, they may also become trapped by obstacles such as logjams and standing trees on floodplains and in secondary channels. Thus, the fluvial export of LW pieces is low in large watersheds.


Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2009, vol. 34, n°. 6, p. 786-800, nombre de pages : 15, Références bibliographiques : 2 p.

Date :
2009

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