Discharge and sand transport in the braided zone of the Zaire estuary

Peters, J.J.

doi:10.1016/0077-7579(78)90031-5

Cited by 37 publications

(16 citation statements)

References 4 publications

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“…In 2001 (surveys C to G), five longitudinal tracks almost parallel to the channel banks were surveyed to analyse the migration of bars and dunes during a single flood event using the dune‐tracking method (Peters, , ; Ten Brinke et al , ; Wilbers and Ten Brinke, ).…”

Section: Methodsmentioning

confidence: 99%

Alternate bars in a sandy gravel bed river: generation, migration and interactions with superimposed dunes

Rodrigues

Mosselman

Claude

et al. 2014

Earth Surf Processes Landf

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A field study was carried out to investigate the development of alternate bars in a secondary channel of the Loire River (France) as a function of discharge variations. We combined frequent bathymetric surveys, scour chains and stratigraphical analysis of deposits with measurements and modelling of flow dynamics. The channel exhibited migrating bars, non-migrating bars and superimposed dunes. Possible mechanisms of bar initiation were found to be chutes associated with changes of bank direction and instability resulting from interactions between existing bars during the fall in water level after floods. We propose that the reworking of bar sediments during low flows (high width-to-depth ratio β), reinforced by high values of the Shields mobility parameter, can explain the formation or re-generation of new alternate migrating bars during a subsequent flood. The migration pattern of the bars was found to be cyclic and to depend mainly on (i) channel layout and (ii) the dynamics of superimposed dunes with heights and lengths depending on location and discharge value. For instance, the hysteresis affecting the steepness of dunes influences the flow resistance of the dunes as well as the celerity of migrating bars during flood events. We compare the findings from the field with results from theoretical studies on alternate bars. This gives insight in the phenomena occurring in the complex setting of real rivers, but it also sheds light on the extent to which bar theories based on idealized cases can predict those phenomena.

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Section: Methodsmentioning

confidence: 99%

Alternate bars in a sandy gravel bed river: generation, migration and interactions with superimposed dunes

Rodrigues

Mosselman

Claude

et al. 2014

Earth Surf Processes Landf

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“…Many published profiles appear to be made up of several relatively flat reaches, linked by steeper or more convex reaches. Profiles of large and small rivers in Europe, the U.S., and Africa are characterized by overall convex shapes, straight and convex reaches, and/or by sharp, local convexities that outcrop along their respective profiles (e.g., Woodford 1951;McKeown et al 1988;Pavich et al 1989;Brice 1964;Peters 1978;L. B. Leopold pers.…”

Section: Introductionmentioning

confidence: 99%

Longitudinal Profile Development into Bedrock: An Analysis of Hawaiian Channels

Seidl¹,

Dietrich²,

Kirchner³

1994

The Journal of Geology

215

185

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Analysis of topographic maps of rivers incised into dated Hawaiian lava flows shows that the long term average bedrock erosion rate along certain reaches is linearly related to stream power. Field observations suggest that two processes may control Hawaiian channel downcutting: (1) stream power-dependent erosion, including abrasion of the channel bed by transported particles, and (2) step-wise lowering caused by knickpoint propagation. Modeling results indicate that a simple stream power-dependent erosion law predicts the straight to weakly convex longitudinal profiles characteristic of Kauai channels but is insufficient to predict two other characteristic features: the upslope propagation of knickpoints and the straight 5-8° channel slopes below the knickpointS; thus more than this single transport law is apparently required to model bedrock channel incision. Field surveys also indicate that significant portions of the channel lengths below the knickpoints are mantled with large boulders. We propose that the boulder mantling of long channel reaches inhibits channel incision, reducing downcutting to a rate set by boulder weathering, breakdown and transport of the material, and perhaps by knickpoint propagation sweeping under the boulder armor. Partial boulder mantling of bedrock-dominated channels is common in mountainous regions, and a theory which takes boulder armoring into account will have broader applications than one which ignores these limiting effects.

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“…However, there is little empirical evidence for this figure (Hovius, ). Indeed, the volume of sand‐sized sediment (equivalent to the bedload) in fluvial sedimentary rocks preserved in the North Sea Basin averages up to 50% of the total sediment volume (Liu & Galloway, ) and in braided sections of the Zaire River sand proportions are estimated to be even higher (Peters, ). Bedload is not accurately known for the Amur River, but it may be significantly higher than that of many other large rivers in East Asia, based on the sand‐rich nature of the deltaic deposits exposed on Sakhalin.…”

Section: Methodsmentioning

confidence: 99%

The sedimentary and tectonic evolution of the Amur River and North Sakhalin Basin: new evidence from seismic stratigraphy and Neogene–Recent sediment budgets

Nicholson

Clift

et al. 2015

Basin Research

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The North Sakhalin Basin in the western Sea of Okhotsk has been the main site of sedimentation from the Amur River since the Early Miocene. In this article, we present regional seismic reflection data and a Neogene–Recent sediment budget to constrain the evolution of the basin and its sedimentary fill, and consider the implications for sediment flux from the Amur River, in particular testing models of continental‐scale Neogene drainage capture. The Amur‐derived basin‐fill history can be divided into five distinct stages: the first Amur‐derived sediments (>21–16.5 Ma) were deposited during a period of transtension along the Sakhalin‐Hokkaido Shear Zone, with moderately high sediment flux to the basin (71 Mt year−1). The second stage sequence (16.5–10.4 Ma) was deposited following the cessation of transtension, and was characterised by a significant reduction in sediment flux (24 Mt year−1) and widespread retrogradation of deltaic sediments. The third (10.4–5.3 Ma) and fourth (5.3–2.5 Ma) stages were characterised by progradation of deltaic sediments and an associated increase in sediment flux (48–60 Mt year−1) to the basin. Significant uplift associated with regional transpression started during this time in southeastern Sakhalin, but the north‐eastward propagating strain did not reach the NE shelf of Sakhalin until the Pleistocene (<2.5 Ma). This uplift event, still ongoing today, resulted in recycling of older deltaic sediments from the island of Sakhalin, and contributed to a substantially increased total sediment flux to the adjacent basinal areas (165 Mt year−1). Adjusted rates to discount these local erosional products (117 Mt year−1) imply an Amur catchment‐wide increase in denudation rates during the Late Pliocene–Pleistocene; however, this was likely a result of global climatic and eustatic effects, combined with tectonic processes within the Amur catchment and possibly a smaller drainage capture event by the Sungari tributary, rather than continental‐scale drainage capture involving the entire upper Amur catchment.

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Discharge and sand transport in the braided zone of the Zaire estuary

Cited by 37 publications

References 4 publications

Alternate bars in a sandy gravel bed river: generation, migration and interactions with superimposed dunes

Alternate bars in a sandy gravel bed river: generation, migration and interactions with superimposed dunes

Longitudinal Profile Development into Bedrock: An Analysis of Hawaiian Channels

The sedimentary and tectonic evolution of the Amur River and North Sakhalin Basin: new evidence from seismic stratigraphy and Neogene–Recent sediment budgets

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