Journal ArticleDOI
Self-formed straight rivers with equilibrium banks and mobile bed. Part 2. The gravel river
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In this paper, singular perturbation techniques are used to obtain a bed stress distribution which allows a mobile bed but immobile banks at bank full or dominant discharge for straight rivers with bed and banks composed of coarse gravel.Abstract:
Rivers are capable of transporting their own bed material without altering their width. However, a naive extension of the threshold theory of canals in coarse alluvium to straight reaches of gravel rivers leads to the stable-channel paradox: transport of bed material is incompatible with a stable width. In this paper singular perturbation techniques are used to obtain a bed stress distribution which allows a mobile bed but immobile banks at bankfull or dominant discharge. This result is used to obtain regime relations for straight rivers with bed and banks composed of coarse gravel.The analysis, although dependent on a series of approximate assumptions for Reynolds-stress closure and sediment transport, provides reasonable agreement with data.read more
Citations
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Bedrock rivers and the geomorphology of active orogens
TL;DR: The results of intense research in the past decade are reviewed in this article, with the aim of highlighting remaining unknowns and suggesting fruitful avenues for further research, including the role of climate-driven denudation in the evolution of orogens.
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A systematic analysis of eight decades of incipient motion studies, with special reference to gravel-bedded rivers
TL;DR: In this article, the authors used data compiled from eight decades of incipient motion studies to calculate dimensionless critical shear stress values of the median grain size, t* c 50.
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Fluvial incision and tectonic uplift across the Himalayas of central Nepal
Jérôme Lavé,Jean Philippe Avouac +1 more
TL;DR: In this article, the pattern of fluvial incision across the Himalayas of central Nepal is estimated from the distribution of Holocene and Pleistocene terraces and from the geometry of modern channels along major rivers draining across the range.
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The large-scale dynamics of grain-size variation in alluvial basins, 1: Theory
TL;DR: In this article, the interplay of various factors causing vertical grain-size changes in alluvial basins using a simple coupled model for sediment transport and downstream partitioning of grain sizes is studied.
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Implications of sediment‐flux‐dependent river incision models for landscape evolution
TL;DR: In this paper, the authors analyze the implications of various sediment-flux-dependent incision models for large-scale topography, in an attempt to identify quantifiable and diagnostic differences between models that could be detected from topographic data or from the transient responses of perturbed systems and explain the apparent ubiquity of mixed bedrock-alluvial channels in active orogens.
References
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Laws of turbulent flow in open channels
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On the cause and characteristic scales of meandering and braiding in rivers
TL;DR: In this paper, a stability analysis of meandering and braiding perturbations in a model alluvial river is described, and a perturbation technique involving a small parameter representing the ratio of sediment transport to water transport is used to obtain the following results.
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Hydraulic geometry of active gravel rivers
TL;DR: In this article, the authors considered the hydraulic geometry of straight reaches of wide, active rivers with beds and banks composed of loose gravel and derived dimensionless relations for hydraulic geometry, which provided channel properties as functions of bed pavement size and two specified variables.
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Self-formed straight rivers with equilibrium banks and mobile bed. Part 1. The sand-silt river
TL;DR: In this paper, the authors formulated a fluid flow model with a series of approximate but reasonable assumptions for straight channels with non-cohesive sand and silt banks and showed that the model can be applied to a more general treatment of natural rivers, which would include various complicating factors such as meandering, sediment sorting and seepage.
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Instability and river channels
TL;DR: In this paper, a linearized stability analysis of the flow of water in a channel with a loose bed and straight banks is described, where it is assumed that the wavelength of the perturbations which develop into meanders or braids is longer than the width of the channel.