Journal ArticleDOI
River channel and bar patterns explained and predicted by an empirical and a physics-based method
TLDR
In this article, the authors compare an empirical stream power-based classification and a physics-based bar pattern predictor to understand general causes of different river channel patterns, finding that increasing potential-specific stream power implies more energy to erode banks and indeed correlates to channels with high width-depth ratio.Abstract:
Our objective is to understand general causes of different river channel patterns. In this paper we compare an empirical stream power-based classification and a physics-based bar pattern predictor. We present a careful selection of data from the literature that contains rivers with discharge and median bed particle size ranging over several orders of magnitude with various channel patterns and bar types, but no obvious eroding or aggrading tendency. Empirically a continuum is found for increasing specific stream power, here calculated with pattern-independent variables: mean annual flood, valley gradient and channel width predicted with a hydraulic geometry relation. ‘Thresholds’, above which certain patterns emerge, were identified as a function of bed sediment size. Bar theory predicts nature and presence of bars and bar mode, here converted to active braiding index (Bi). The most important variables are actual width–depth ratio and nonlinearity of bed sediment transport. Results agree reasonably well with data. Empirical predictions are somewhat better than bar theory predictions, because the bank strength is indirectly included in the empirical prediction. In combination, empirical and theoretical prediction provide partial explanations for bar and channel patterns. Increasing potential-specific stream power implies more energy to erode banks and indeed correlates to channels with high width–depth ratio. Bar theory predicts that such rivers develop more bars across the width (higher Bi). At the transition from meandering to braiding, weakly braided rivers and meandering rivers with chutes are found. Rivers with extremely low stream power and width–depth ratios hardly develop bars or dynamic meandering and may be straight or sinuous or, in case of disequilibrium sediment feed, anastomosing. Copyright © 2010 John Wiley & Sons, Ltd.read more
Citations
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Journal ArticleDOI
Development of the Global Width Database for Large Rivers
TL;DR: The Global Width Database for Large Rivers (GWD-LR) as discussed by the authors was developed by applying the algorithm to the SRTM Water Body Database and the HydroSHEDS flow direction map.
Journal ArticleDOI
Experimental meandering river with chute cutoffs
TL;DR: In this article, the importance of upstream perturbation and chute cutoff development in the evolution and dynamics of a meandering channel pattern was investigated. And the authors concluded that the necessary and sufficient conditions for dynamic meandering gravel bed river are a sustained dynamic upstream perturbing and floodplain formation.
Journal ArticleDOI
Physics‐based modeling of large braided sand‐bed rivers: Bar pattern formation, dynamics, and sensitivity
TL;DR: In this paper, a physics-based morphological model for sand-bed braided rivers has been proposed to reproduce morphology and dynamics characteristic of braided river and determine the model sensitivity to generally used constitutive relations for flow and sediment transport.
Journal ArticleDOI
Morphodynamics: Rivers beyond steady state
Journal ArticleDOI
How do big rivers come to be different
Philip Ashworth,John Lewin +1 more
TL;DR: In this article, the authors used global satellite imagery and ground field-experience to explain and illustrate why and how big rivers are strongly differentiated from smaller rivers and how they operate and whether they are explicably different from each other.
References
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Formulas for Bed-Load transport
E. Meyer-Peter,R. Müller +1 more
TL;DR: In this article, an attempt is made to derive an empirical law of bed-load transport based on recent experimental data and the results and interpretation of tests already made known in former publications of the Laboratory for Hydraulic Research and Soil Mechanics at the Federal Institute of Technology, Zurich.
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A classification of natural rivers
TL;DR: In this paper, a classification system for natural rivers is presented in which a morphological arrangement of stream characteristics is organized into relatively homogeneous stream types, and morphologically similar stream reaches are divided into 7 major stream type categories that differ in entrenchment, gradient, width/depth ratio, and sinuosity in various landforms.
Book
Dynamics of marine sands
TL;DR: Dynamics of marine sands' specifically deals with coastal and offshore sea areas, as well as rivers and estuaries, for sand and gravel sediments as mentioned in this paper, presented a convenient and useable introduction to sediment processes in a form that is accessible to a wide readership.
Journal ArticleDOI
Riverine landscape diversity
TL;DR: In this article, a broad synthesis of riverine landscape diversity is presented, beginning with an account of the variety of landscape elements contained within river corridors and concluding with the role of hydrological connectivity.