Coupled simulations of fluvial erosion and mass wasting for cohesive river banks
Darby, Stephen E., Rinaldi, Massimo and Dapporto, Stefano (2007) Coupled simulations of fluvial erosion and mass wasting for cohesive river banks. Journal of Geophysical Research, 112, (F03022), 1-15. (doi:10.1029/2006JF000722).
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The erosion of sediment from riverbanks affects a range of physical and ecological issues.
Bank retreat often involves combinations of fluvial erosion and mass-wasting, and in recent
years bank retreat models have been developed that combine hydraulic erosion and limit
equilibrium stability models. In related work, finite element seepage analyses have also been
used to account for the influence of pore-water pressure in controlling the onset of masswasting.
This paper builds on these previous studies by developing a simulation modeling
approach in which the hydraulic erosion, finite element seepage and limit equilibrium
stability models are, for the first time, fully coupled. Application of the model is
demonstrated by undertaking simulations of a single flow event at a single study site for
scenarios where (i) there is no fluvial erosion and the bank geometry profile remains constant
throughout, (ii) there is no fluvial erosion but the bank profile is deformed by simulated
mass-wasting, and (iii) the bank profile is allowed to freely deform in response to both
simulated fluvial erosion and mass-wasting. The results are limited in scope to the specific
conditions encountered at the study site, but they nevertheless demonstrate the significant
role that fluvial erosion plays in steepening the bank profile, or creating overhangs, thereby
triggering mass-wasting. However, feedbacks between the various processes also lead to
unexpected outcomes. Specifically, fluvial erosion also affects bank stability indirectly, as
deformation of the bank profile alters the hydraulic gradients driving infiltration into the
bank, thereby modulating the evolution of the pore-water pressure field. Consequently, the
frequency, magnitude and mode of bank erosion events in the fully coupled scenario differ
from the two scenarios in which not all the relevant bank process interactions are included.
|Additional Information:||This paper is novel in developing the first bank erosion simulation to couple process sub-models that account for the combined effects of fluvial erosion, seepage and mass-wasting. Simulation results provide new insight into the frequency, magnitude and mode of bank erosion events as compared to previous (uncoupled) modelling studies.|
|Subjects:||G Geography. Anthropology. Recreation > GE Environmental Sciences
G Geography. Anthropology. Recreation > GB Physical geography
|Divisions:||University Structure - Pre August 2011 > School of Geography > Environmental Processes and Change
|Date Deposited:||13 Jul 2007|
|Last Modified:||27 Mar 2014 18:30|
|RDF:||RDF+N-Triples, RDF+N3, RDF+XML, Browse.|
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