Discrimination of alluvial and mixed bedrock–alluvial multichannel river networks

Auteur(s) et Affiliation(s)



Description :
This paper explores the use of planview morphological metrics to quantitatively describe and distinguish mixed bedrock–alluvial multichannel networks from alluvial multichannel networks. The geometries of the channel planforms of 2 bedrock-constrained networks (Mekong and Orange rivers) are compared with the classic alluvial anastomosed Upper Columbia River and the wandering Ganga River. Widely recognized indices utilized include : channel link count and channel sinuosity, and less common metrics : network bifurcation angles and island shape characteristics (aspect ratio, compactness, roundness and convexity). Bifurcation angles for all 4 multichannel rivers are significantly greater than angles reported for braiding rivers. Island convexity clearly discriminates the 2 alluvial rivers from the 2 bedrock-influenced rivers. The width of the macrochannel, in which each network develops, has a positive influence on the number of channel links and is further related to channel slope variations. The geometry of multichannel networks are often laterally constrained.


Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2013, vol. 38, n°. 11, p. 1299-1361, nombre de pages : 63, Références bibliographiques : 2 p.

Date :
2013

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