TY - JOUR
T1 - Mechanisms of anabranch avulsion within gravel-bed braided rivers
T2 - Observations from a scaled physical model
AU - Leddy, J. O.
AU - Ashworth, P. J.
AU - Best, J. L.
N1 - Copyright:
Copyright 2012 Elsevier B.V., All rights reserved.
PY - 1993
Y1 - 1993
N2 - The physical modelling of gravel-bed braided rivers, using a 1:20 Froude scale model, permits analysis of the types and relative occurrence of different avulsion mechanisms. Anabranch avulsion within braided rivers involves three main mechanisms: choking avulsion caused by blockage of one channel by a sediment lobe, constriction avulsion produced by deflection, confinement and subsequent diversion of the flow by a barform and apex avulsion following erosion at the outside of sinuous thalwegs and confined meander bends. Each avulsion mechanism is described and analysis of the abundance of each type illustrates choking avulsion to be predominant without braided rivers. Three factors are found to control anabranch avulsions, namely flow discharge, sediment flux and floodplain topography. These are briefly discussed together with the implications of avulsion type for the alluvial architecture of gravelly braided alluvium.
AB - The physical modelling of gravel-bed braided rivers, using a 1:20 Froude scale model, permits analysis of the types and relative occurrence of different avulsion mechanisms. Anabranch avulsion within braided rivers involves three main mechanisms: choking avulsion caused by blockage of one channel by a sediment lobe, constriction avulsion produced by deflection, confinement and subsequent diversion of the flow by a barform and apex avulsion following erosion at the outside of sinuous thalwegs and confined meander bends. Each avulsion mechanism is described and analysis of the abundance of each type illustrates choking avulsion to be predominant without braided rivers. Three factors are found to control anabranch avulsions, namely flow discharge, sediment flux and floodplain topography. These are briefly discussed together with the implications of avulsion type for the alluvial architecture of gravelly braided alluvium.
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U2 - 10.1144/GSL.SP.1993.075.01.07
DO - 10.1144/GSL.SP.1993.075.01.07
M3 - Article
AN - SCOPUS:80052588155
VL - 75
SP - 119
EP - 127
JO - Geological Society Special Publication
JF - Geological Society Special Publication
SN - 0305-8719
ER -