The influence of dilution on downstream channel sedimentation in large rivers : the Yellow River, China

Auteur(s) et Affiliation(s)



Description :
Due to the temporal decoupling of water and sediment sources in a large river basin, a flood from a sediment source area with high suspended sediment concentration (SSC) may be diluted by flow from a major runoff source area with low SSC. Here, this dilution effect is considered for 145 flood events from the Yellow River. Two indices (β1 and β2) describing the dilution effect are proposed, based on water and sediment from the clear water source area and the coarse sediment producing area. Regression equations between channel sedimentation (Sdep) and β1 and β2 are established based on flood events and annual data, respectively. The results show that dilution reduces channel sedimentation in the lower reaches and that this is related to a reduced frequency of hyperconcentrated flows in the lower reaches. The Longyangxia Reservoir for hydro-electric generation has stored huge quantities of clear runoff from the upper Yellow River during high-flow season since 1985, greatly reducing the dilution of the hyperconcentrated floods and therefore enhancing sedimentation in the lower reaches.


Type de document :
Article de périodique

Source :
Earth surface processes and landforms, issn : 0197-9337, 2014, vol. 39, n°. 4, p. 450-462, nombre de pages : 13, Références bibliographiques : 1 p.

Date :
2014

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