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Rational regime model of alluvial channel morphology and response
  • Rational regime model of alluvial channel morphology and response
  • Bank erosion ; Carrying capacity ; Channel geometry ; Discharge ; Hydrological regime ; Model ; Stream
  • A theoretical model is developed for predicting equilibrium alluvial channel form. The concept of greatest relative stability, achieved by maximizing resistance to flow in the fluvial system, is presented as the basis for an optimization condition
  • for alluvial systems. Discharge, sediment supply (quantity and calibre) and valley gradient are accepted as independent governing variates. The model is used to define a dimensionless alluvial state space characterized by aspect ratio, relative roughness
  • , and dimensionless shear stress or, equivalently, channel slope. Discussion of the results.
A model of channel response in disturbed alluvial channels
  • A model of channel response in disturbed alluvial channels
  • The adjustment of channel geometry and phases of channel evolution are characterized by six process-oriented stages of morphologic development : premodified, constructed, degradation, threshold, aggradation, and restabilization. Downcutting and toe
  • removal during the degradation stage causes bank failure by mass wasking when the critical height and angle of the bank material is exceeded (threshold stage). Channel widening continues through the aggradation stage as the slough line develops
  • as an initial site of lower-bank stability. Alternate channel bars form during the restabilization stage and represent incipient meandering of the channel.
Field evaluation of empirical equations in straight alluvial channels
  • Field evaluation of empirical equations in straight alluvial channels
  • Alluvial channel ; Carrying capacity ; Channel geometry ; Fluvial processes ; Illinois ; Model ; Sedimentology ; Stream flow ; United States
  • Capacité de charge ; Chenal alluvial ; Ecoulement fluvial ; Etats-Unis ; Fluviatile ; Géométrie hydraulique ; Illinois ; Modèle ; Sédimentologie
  • south of Champaign, Illinois. Data were collected on channel form, gradient, alternate bar dimensions, bar sediment size, and flow conditions over a two-year study period.
The frictional resistance characteristics of a bedrock-influenced river channel
  • The frictional resistance characteristics of a bedrock-influenced river channel
  • Alluvial channel ; Braided channel ; Channel geometry ; Mpumalanga ; Riparian vegetation ; River bed ; Roughness ; Runoff ; South Africa ; Stream ; Stream flow
  • Afrique du Sud ; Chenal alluvial ; Chenal anastomosé ; Cours d'eau ; Ecoulement ; Ecoulement fluvial ; Géométrie hydraulique ; Lit fluvial ; Mpumalanga ; Rugosité ; Végétation ripicole
  • This paper presents the results of a detailed investigation of total flow resistance variation for 5 channel types on the Sabie River, South Africa (cohesive, mixed anastomosed, uncohesive mixed anastomosed, mixed pool-rapid, alluvial braided
  • and alluvial single thread) over a range of discharges. It is suggested that the slightly elevated resistance coefficients recorded in the alluvial channel types are the result of the vegetation roughness component, operating when the macro-channel bar features
Discrimination of channel patterns for gravel- and sand-bed rivers
  • Discrimination of channel patterns for gravel- and sand-bed rivers
  • Braided channel ; Discriminant analysis ; Gravel ; Meander ; River bed ; Runoff ; Sand ; Shear stress ; Stream ; Stream flow
  • Based on data from around 200 alluvial rivers in several countries, a systematic comparison of flow shear stress and stream power has been made between sand- and gravel-bed rivers. The formation of channel pattern can be regarded as the outcome
  • of sediment transport and channel bank constraints in an alluvial river. To overcome the difficulty of quantifying channel bank constraints, channel width/depth ratio and a dimensionless channel width index are used to reflect it indirectly.
A stability criterion inherent in laws governing alluvial channel flow
  • A stability criterion inherent in laws governing alluvial channel flow
  • Carrying capacity ; Channel geometry ; Mathematical hydrology ; Runoff ; Sediment transport ; Stream ; Stream flow
  • The stability criterion of maximum flow efficiency (MFE) has previously been found inherent in typical alluvial channel flow relationships, and this study investigates the general nature of this criterion using a wider range of flow resistance
  • and bedload transport formulae. This study provides support for the use of the criteria of MFE, maximum sediment transporting capacity and minimum stream power for understanding the operation of alluvial rivers, and also addresses limitations to the direct
Adjustment and recovery of unstable alluvial channels: identification and approaches for engineering management
  • Adjustment and recovery of unstable alluvial channels: identification and approaches for engineering management
  • This paper presents interdisciplinary techniques that can be used to identify the type and cause(s) of channel instability, determine past, present and future trends of channel adjustment, and assess the applicability of various engineering
  • practices aimed at controlling channel adjustments. In particular, this paper will address channels that have become incised, and channel reaches that exhibit characteristics of instability related to localized flow problems.
Controls on channel form along bedrock-influenced alluvial streams in South-Central Indiana
  • Controls on channel form along bedrock-influenced alluvial streams in South-Central Indiana
  • Carrying capacity ; Channel geometry ; Fluvial processes ; Indiana ; Lithology ; Principal components analysis ; River bed ; Sedimentology ; Statistics ; United States
  • The primary objective of this investigation is to assess the influence of bedrock geology on channel form along alluvial streams that are characterized by bedrock exposures and thus are significantly influenced by the underlying strata. The analysis
  • is performed by quantifying and comparing variables describing channel form and sedimentology along streams developed in siliciclastic rocks with streams traversing primarily carbonate lithologies.
Prediction of alluvial channel pattern of perennial rivers
  • Prediction of alluvial channel pattern of perennial rivers
  • Braided channel ; Carrying capacity ; Channel geometry ; Discharge ; Flood ; Floodplain ; Fluvial processes ; Forecast ; Meander ; River bed
  • This paper attempts to predict the individual channel pattern of perennial rivers from independent boundary conditions defined by the river discharge and the bed material. The analysis is limited to wide alluvial floodplains, which do not restrict
Grain size, sediment transport and alluvial channel pattern
  • Grain size, sediment transport and alluvial channel pattern
  • Braided channel ; Carrying capacity ; Channel geometry ; England ; Forecast ; Grain size distribution ; Meander ; Methodology ; Stream ; United Kingdom
  • The Shields parameter, a dimensionless bed shear stress which can be expressed as a ratio of the slope, depth and characteristic properties of bed material in an alluvial channel, has been observed in natural rivers to take on modal values
  • for the regime of bedload, mixed-load and suspension transport. The conditions correspond to channel geometries associated with conserved sediment flux. These findings are extended here to accommodate the effects of channel width in the context of a comprehensive
  • data set on stable, perennial rivers. This new analysis reconcilies existing empirical and theoretical approaches to predict alluvial geometry.
Channel avulsion on alluvial fans in southern Arizona
  • Channel avulsion on alluvial fans in southern Arizona
  • Alluvial cone ; Arizona ; Flood ; Forecast ; Longitudinal section ; Model ; Photointerpretation ; Stream ; United States of America ; Watershed
  • Historical aerial photographs and field observations on 5 fluvially dominated alluvial fans in southern Arizona demonstrate that channel avulsion invariably occurs where bank heights are low and often at channel bends. 5 distinct channel
  • morphologies observed on the fans are related to different stages of the avulsion process and can be used to identify areas on a fan surface that are prone to avulsion. A descriptive model of channel avulsion illustrates how the morphology of a single channel
Anabranching rivers : ridge-form alluvial channels in tropical northern Australia
  • Anabranching rivers : ridge-form alluvial channels in tropical northern Australia
  • Australia ; Braided channel ; Carrying capacity ; Channel geometry ; Riparian vegetation ; Sand ; Stream ; Stream flow ; Tropical zone ; Western Australia
  • This paper examines the existence of sand-dominated ridge-form anabranching rivers in the Kimberley region of Western Australia. It describes their channel and ridge morphology, sedimentology and stratigraphy, discusses stream flow and sediment
  • transport, and considers mechanisms for their formation and continued existence as an equilibrium channel form.
Morphological response to river engineering and management in alluvial channels in Italy
  • Morphological response to river engineering and management in alluvial channels in Italy
  • Channel geometry ; Fitting ; Human impact ; Hydraulic works ; Italy ; River bed ; Stream ; Twentieth Century
  • In this paper, published studies and existing data on recent channel adjustments of rivers in Italy are reviewed and discussed. The aims are to : reconstruct a general outline of river channel adjustments and their causes in the recent past
  • (generally the last 100 years); define the general temporal trends of channel changes and the different styles of adjustment; compare the morphological changes with those observed in fluvial systems outside Italy.
The sinuosity of alluvial river channels in the seasonally wet tropical environment: case study of river Elemi, southwestern Nigeria
  • The sinuosity of alluvial river channels in the seasonally wet tropical environment: case study of river Elemi, southwestern Nigeria
  • Channel geometry ; Fluvial erosion ; Fluvial processes ; Longitudinal section ; Nigeria ; River management ; Stream ; Tropical zone ; Vegetation
  • The aim of this paper is to improve the understanding of the nature and dynamics of river channel patterns in the humid tropics through detailed survey and quantitative analysis of the plan geometry of alluvial streams in a seasonally wet humid
Discrimination of alluvial and mixed bedrock–alluvial multichannel river networks
  • Discrimination of alluvial and mixed bedrock–alluvial multichannel river networks
  • Asia ; Bifurcation ; Braided channel ; Channel geometry ; Columbia ; Comparative study ; Drainage network ; Ganges River ; India ; Meander ; Mekong ; North America ; South Africa ; Stream
  • This paper explores the use of planview morphological metrics to quantitatively describe and distinguish mixed bedrock–alluvial multichannel networks from alluvial multichannel networks. The geometries of the channel planforms of 2 bedrock
  • -constrained networks (Mekong and Orange rivers) are compared with the classic alluvial anastomosed Upper Columbia River and the wandering Ganga River. Widely recognized indices utilized include : channel link count and channel sinuosity, and less common
  • convexity clearly discriminates the 2 alluvial rivers from the 2 bedrock-influenced rivers. The width of the macrochannel, in which each network develops, has a positive influence on the number of channel links and is further related to channel slope
Bank accretion and the development of vegetated depositional surfaces along modified alluvial channels
  • Bank accretion and the development of vegetated depositional surfaces along modified alluvial channels
  • The purposes of this paper are to describe and interpret the initiation and development of bank-depositional surfaces and associated revegetation in relation to fluvial recovery from channelization. Special emphasis is given to variation in bank
Comparison of hydraulic geometry between sand- and gravel-bed rivers in relation to channel pattern discrimination
  • Comparison of hydraulic geometry between sand- and gravel-bed rivers in relation to channel pattern discrimination
  • Alluvial channel ; Braided channel ; Carrying capacity ; Channel geometry ; Classification ; Data base ; Discharge ; Discriminant analysis ; Gravel ; Meander ; Sand ; Stream ; World
  • Analyse discriminante ; Base de données ; Capacité de charge ; Chenal alluvial ; Chenal anastomosé ; Classification ; Cours d'eau ; Débit ; Gravier ; Géométrie hydraulique ; Monde ; Méandre ; Sable
  • A comparison has been made between the hydraulic geometry of sand- and gravel-bed rivers, based on data from alluvial rivers around the world. The results indicate a significant difference in hydraulic geometry. On this basis, some diagrams
  • for discrimination of meandering and braided channel patterns have been established. To predict the development of channel patterns under different natural conditions, the pattern discriminator should be searched on the basis of independent or at least semi
Surface ancient channels in Hebei Plain.
  • Surface ancient channels in Hebei Plain.
  • The pattern of old abandoned channels differs between geomorphic zones. In the pluvial-alluvial piedmont fan zone the pattern is fan-like| in the alluvial plain of mid-Hebei it is parallel, while in the lowest reaches near the sea the pattern
  • is radiating. The ages of these channels are identified ranging from late Pleistocene to historic Han Dynasty. Neotectonic movements which are related to the formation of these channels produced differential uplifts in different parts of the plain. (TNC).
The influence of debris flows on channels and valley floors in the Oregon Coast Range, U.S.A.
  • The influence of debris flows on channels and valley floors in the Oregon Coast Range, U.S.A.
  • The A. presents a field study of the erosional and depositional characteristics of debris flows and their influence on alluvial channels and valley floors.
Incremental aggradation on the Okavango Delta-fan, Botswana
  • Botswana ; Cône alluvial ; Fluviatile ; Géographie physique ; Géomorphodynamique ; Lit fluvial ; Milieu humide ; Topographie ; Tourbe
  • This work has confirmed that channel switching is the result of aggradation within the channel systems. Initially, new channel systems are erosive but later in their evolution both channel bed and adjacent swamp (peat) areas begin to aggrade
  • . This phase leads to a change in channel gradient and causes the channel to become moribund. Abandonment follows with consequent dessication of the peat. Burning of the peat completes the cycle of the channel evolution.