Author(s): Arjan P. Tuijnder; Jan S. Ribberink

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Keywords: Bedform dimensions; immobile layer; riverbed roughness; sand gravel mixture; supply limitation

Abstract: This paper presents a study on the relationship between supply-limited bedform formation and the hydraulic roughness of the riverbed. The results of several new sets of flume experiments with supply-limited or partial transport conditions with bimodal sediment are presented. The results show that both the bedform and grain-related roughness show a clear dependency on the degree of supply limitation. This variation can be attributed to the reduction of the bedform dimensions with a decreasing availability of mobile sediment and an increasing exposure of the usually coarser sublayer (armour layer or pavement) that causes the supply limitation. In the present study, we present a new method to predict the exposure of the immobile sublayer, as well as the bedform and grain-related roughness under supply-limited conditions.

DOI: https://doi.org/10.1080/00221686.2012.719201

Year: 2012