TY - JOUR
T1 - Relative importance of fluvial input and wave energy in controlling the timescale for distributary-channel avulsion
AU - Swenson, John B.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2005/12/16
Y1 - 2005/12/16
N2 - Existing avulsion models are decoupled from nearshore processes. Here, I explore quantitatively how the interplay of wave energy with fluvial input of sediment and water controls the aggradation rate and avulsion timescale of a single distributary channel. My approach rigorously couples a diffusive, moving-boundary theory of fluvial morphodynamics with a diffusive treatment of shoreface morphodynamics. I use this deterministic model to quantify the time required for channel-belt superelevation, normalized with channel depth, to attain a threshold value for nodal avulsion at a specified channel location. Increasing the long-term wave energy relative to fluvial input by an order of magnitude increases longshore sediment dispersal, thereby reducing the rate of channel-belt aggradation and associated seaward extension and increasing the avulsion timescale by a factor of approximately 50. Far-field processes eventually limit the ability of wave energy to suppress avulsion.
AB - Existing avulsion models are decoupled from nearshore processes. Here, I explore quantitatively how the interplay of wave energy with fluvial input of sediment and water controls the aggradation rate and avulsion timescale of a single distributary channel. My approach rigorously couples a diffusive, moving-boundary theory of fluvial morphodynamics with a diffusive treatment of shoreface morphodynamics. I use this deterministic model to quantify the time required for channel-belt superelevation, normalized with channel depth, to attain a threshold value for nodal avulsion at a specified channel location. Increasing the long-term wave energy relative to fluvial input by an order of magnitude increases longshore sediment dispersal, thereby reducing the rate of channel-belt aggradation and associated seaward extension and increasing the avulsion timescale by a factor of approximately 50. Far-field processes eventually limit the ability of wave energy to suppress avulsion.
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U2 - 10.1029/2005GL024758
DO - 10.1029/2005GL024758
M3 - Article
AN - SCOPUS:31544479237
SN - 0094-8276
VL - 32
SP - 1
EP - 5
JO - Geophysical Research Letters
JF - Geophysical Research Letters
IS - 23
M1 - L23404
ER -