Experimental Study of Sediment Transport in Meandering Channels

Yilmaz, Levent

doi:10.1007/s11269-007-9156-1

Cited by 11 publications

(4 citation statements)

References 15 publications

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“…The channel curvature therefore affects the routing of fine and coarse grain size fractions of the bed load, which are disproportionately transported in different regions of the channel: finer particles are transported in great quantity in the inner portions of bends and coarser grains are disproportionately moved through the outer regions (Parker and Andrews, 1985;Ikeda, 1989;Bridge, 1992), as documented in field studies for both sand-bed (Bridge and Jarvis, 1976;Dietrich andSmith, 1983, 1984) and gravel-bed (Clayton and Pitlick, 2007) rivers, as well as experimental channels (Nelson et al, 2010), though other experimental studies suggest that grain size sorting effects are difficult to scale appropriately in flume studies of meandering rivers (Yilmaz, 2008). Results from these and other studies (e.g., Whiting and Dietrich, 1991;Lisle et al, 2000) suggest that small, limited areas of the bed may convey large portions of the bed load in curved reaches.…”

Section: Introductionmentioning

confidence: 99%

Spatial Variations in Excess Shear Stress in a Gravel-Bed River Bend

Clayton

2012

Physical Geography

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Detailed topographic and hydraulic measurements were obtained in a bend of the Colorado River in Rocky Mountain National Park, Colorado, to characterize flow through the reach with a two-dimensional model. When compared with the threshold Shields stress required for particle entrainment (τ * c ), estimates of Shields stress (τ * ) obtained from the model provided a distribution of excess stress through the reach for a range of discharges. Magnitudes of excess stress have been related (elsewhere) to transport phase: ratios of τ * /τ * c between 1 and 2 imply partial mobility; τ * /τ * c ≥ 2 suggests a fully mobile bed. This study found that at ~bankfull flow, areas of excess stress (1 < τ * /τ * c < 2, and τ * /τ * c ≥ 2) approach roughly 60% and 10% of the bed, respectively. For the peak discharge observed during the field campaign, areal coverage of excess stress probably increased to approximately 85 and 15%, respectively, suggesting that all of the bed was experiencing at least some degree of sediment mobility. These results suggest that small regions of the channel contribute disproportionately to the overall sediment flux at high flows, that the size of these regions increases with stage, and that this effect amplifies with channel curvature.

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Section: Introductionmentioning

confidence: 99%

Spatial Variations in Excess Shear Stress in a Gravel-Bed River Bend

Clayton

2012

Physical Geography

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“…According to model hypotheses, and provided that overbank flows are not required for neck cutoff (Gay et al., 1998; Hooke, 1995), the two runs were carried out at constant Q = 0.00025 m 3 /s, which was a flow rate value smaller than the bankfull limit. The two runs differed in terms of critical meander centerline curvature radius r 0 and, therefore, in terms of r 0 /B ratio, which is widely recognized as a morphological factor crucially affecting lateral migration rate (Hickin & Nanson, 1984; Richard et al., 2005) and meander cutting (Crosato, 2009; Yilmaz, 2008).…”

Section: Laboratory Experiments and Theory Validationmentioning

confidence: 99%

On the Prediction of the Characteristic Times of River Meander Cutoff Sequence: Theoretical Model and Comparison With Laboratory and Field Observations

Pannone

2022

Water Resources Research

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Natural evolution of lowland rivers typically involves the continuous elongation of their axis, the formation of simple or compound loops, and the occurrence of cutoffs. Cutoff is the bypass of a meander loop by a shorter straight path and the consequent formation of an abandoned reach, the so-called oxbow lake. Meander cutoffs in alluvial valleys form either by the progressive narrowing of the neck until the two opposite limbs meet, or by the formation of a chute channel directly across the meander neck itself. Lewis and Lewin (1983) reserve the term "neck cutoff" to cases in which the opposite limbs of the bend were considerably less than a channel width apart at the time of breaching, while using "chute cutoff" for cases in which a much longer breach channel was created. Since cutoff events are cyclically sporadic and are recognized to trigger important geomorphologic processes (Mosley, 1975), their occurrence practically identifies two different characteristic timescales: a short timescale, which refers to the evolution of single meanders before the cutoff, and a long timescale, which includes multiple, more or less periodic cutoffs (see also Camporeale et al., 2005;Hooke, 2004).The study of the role of cutoff occurrence at large river dynamics timescales is usually carried out according to two different though interconnected approaches: the descriptive/experimental and the numerical method. The descriptive method dates back to very classical studies, where it was aimed at deriving some empirical laws that could relate the hydraulics of the process to the representative geomorphological parameters (e.g., Carlston, 1965;Hansen, 1967;Leopold & Wolman, 1960). From then, several laboratory/field surveys concerning cutoff (chute or neck) events, oxbow lake formation and post-cutoff adjustments have been carried out (e.g.,

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“…One of such studies was study of Yilmaz (2008), who performed experimental study of sediment transport in meandering channels measured in a laboratory ume and those measurements were evaluated and compared with previous model studies. They found that the values of the calculated sediment transport rates are generally overestimated.…”

Section: Introductionmentioning

confidence: 99%

Pollutant transport via sediments in medium-sized meandering rivers: the example of barium in Kupa River (Croatia)

Frančišković-Bilinski

Maldini²,

Bilinski

et al. 2022

Environ Earth Sci

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The aim of our study is to expand the world-wide knowledge about pollutant transport in sediments of medium-sized meandering rivers and to explain barium distribution in Kupa River (Croatia), as it showed as an ideal "natural laboratory".Sampling was performed twice at the same places with the time span of 15 years to see the changes in Ba concentrations after that period. Ba was analyzed using ICP-MS method on clay + silt sediment fraction (<63 µm). Modelling was performed in R environment (R version 3.5.1, 2018) and for solving the sediment transport equation of Ba in Kupa River a program based on nite differences is constructed.After barite mine ceased operation in 1990, Ba is still entering Kupica and Kupa rivers, as karstic underground still contains large amounts of barite waste. Ba concentrations in Kupa River sediments are still increasing consequently along the whole river length, except in Kupica River and rst downstream sample in Kupa River. It seems that in this part of river course erosion exceeded deposition processes. Also, there is an indication of changing the way of underground Ba transport. Erosion and deposition processes lead to formation of peak of Ba concentrations in the lower course of the Kupa River.Most important conclusion is that the mentioned peak was formed under one or two ood episodes, when sediment eroded from the upstream locations and was brought and deposited in the lower course of the river. Our modelling predicts that Ba source will not cease completely during the next 20 years.

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Experimental Study of Sediment Transport in Meandering Channels

Cited by 11 publications

References 15 publications

Spatial Variations in Excess Shear Stress in a Gravel-Bed River Bend

Spatial Variations in Excess Shear Stress in a Gravel-Bed River Bend

On the Prediction of the Characteristic Times of River Meander Cutoff Sequence: Theoretical Model and Comparison With Laboratory and Field Observations

Pollutant transport via sediments in medium-sized meandering rivers: the example of barium in Kupa River (Croatia)

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