Bank Erosion Algorithm for Numerical Modelling of Channel Width Adjustments

Author(s):  
Stephen E. Darby ◽  
Colin R. Thorne

2008 ◽  
Vol 33 (14) ◽  
pp. 2174-2200 ◽  
Author(s):  
Rebecca Bartley ◽  
Rex J. Keen ◽  
Aaron A. Hawdon ◽  
Peter B. Hairsine ◽  
Mark G. Disher ◽  
...  


2018 ◽  
Vol 6 (4) ◽  
pp. 1115-1137 ◽  
Author(s):  
Virginia Ruiz-Villanueva ◽  
Alexandre Badoux ◽  
Dieter Rickenmann ◽  
Martin Böckli ◽  
Salome Schläfli ◽  
...  

Abstract. On 24 July 2014, an exceptionally large flood (recurrence interval ca. 150 years) caused large-scale inundations, severe overbank sedimentation, and damage to infrastructure and buildings along the Emme River (central Switzerland). Widespread lateral bank erosion occurred along the river, thereby entraining sediment and large wood (LW) from alluvial forest stands. This work analyzes the catchment response to the flood in terms of channel widening and LW recruitment and deposition, but also identifies the factors controlling these processes. We found that hydraulic forces (e.g., stream power index) or geomorphic variables (e.g., channel width, gradient, valley confinement), if considered alone, are not sufficient to explain the flood response. Instead, the spatial variability of channel widening was first driven by precipitation and secondly by geomorphic variables (e.g., channel width, gradient, confinement, and forest length). LW recruitment was mainly caused by channel widening (lateral bank erosion) and thus indirectly driven by precipitation. In contrast, LW deposition was controlled by channel morphology (mainly channel gradient and width). However, we also observed that extending the analysis to the whole upper catchment of the Emme River by including all the tributaries and not only to the most affected zones resulted in a different set of significant explanatory or correlated variables. Our findings highlight the need to continue documenting and analyzing channel widening after floods at different locations and scales for a better process understanding. The identification of controlling factors can also contribute to the identification of critical reaches, which in turn is crucial for the forecasting and design of sound river basin management strategies.





2016 ◽  
Vol 745 ◽  
pp. 032069 ◽  
Author(s):  
Yaxin Su ◽  
Bingtao Zhao ◽  
Feining Lei ◽  
Wenyi Deng


2019 ◽  
Author(s):  
SAROJ KARKI ◽  
KARKI NAKAGAWA ◽  
KENJI KAWAIKE ◽  
MASAKAZU HASHIMOTO ◽  
YUJI HASEGAWA ◽  
...  


2014 ◽  
Vol 760 ◽  
pp. 127-174 ◽  
Author(s):  
Esther C. Eke ◽  
M. J. Czapiga ◽  
E. Viparelli ◽  
Y. Shimizu ◽  
J. Imran ◽  
...  

AbstractThis research implements a recently proposed framework for meander migration, in order to explore the coevolution of planform and channel width in a freely meandering river. In the model described here, width evolution is coupled to channel migration through two submodels, one describing bank erosion and the other describing bank deposition. Bank erosion is modelled as erosion of purely non-cohesive bank material damped by natural armouring due to basal slump blocks, and bank deposition is modelled in terms of a flow-dependent rate of vegetal encroachment. While these two submodels are specified independently, the two banks interact through the medium of the intervening channel; the morphodynamics of which is described by a fully nonlinear depth-averaged morphodynamics model. Since both banks are allowed to migrate independently, channel width is free to vary locally as a result of differential bank migration. Through a series of numerical runs, we demonstrate coevolution of local curvature, width and streamwise slope as the channel migrates over time. The correlation between the local curvature, width and bed elevation is characterized, and the nature of this relationship is explored by varying the governing parameters. The results show that, by varying a parameter representing the ratio between a reference bank erosion rate and a reference bank deposition rate, the model is able to reproduce the broad range of river width–curvature correlations observed in nature. This research represents a step towards providing general metrics for predicting width variation patterns in river systems.



2018 ◽  
Author(s):  
Virginia Ruiz-Villanueva ◽  
Alexandre Badoux ◽  
Dieter Rickenmann ◽  
Martin Böckli ◽  
Salome Schläfli ◽  
...  

Abstract. On July 24, 2014, an exceptionally large flood (recurrence interval ca. 150 years) caused large-scale inundations, severe overbank sedimentation and damage to infrastructures and buildings along the Emme river (central Switzerland). Widespread lateral bank erosion occurred along the river, thereby entraining sediment and large wood (LW) from alluvial forest stands. This work analyses the catchment response to the flood in terms of channel widening and LW recruitment and deposition, but also identifies the factors controlling these processes. We found that hydraulic forces (e.g., stream power index) or geomorphic variables (e.g., channel width, gradient, valley confinement), if considered alone, are not sufficient to explain the flood response. Instead, spatial variability of channel widening was firstly driven by precipitation, and secondary by geomorphic variables (e.g., channel width, gradient, confinement and forest length). LW recruitment was mainly caused by channel widening (lateral bank erosion) and thus also controlled by precipitation. In contrast, LW deposition was controlled by channel morphology (mainly channel gradient and width). However, we also observed that extending the analysis to the whole upper catchment of the Emme river, including all the tributaries and not only to the most affected zones, resulted in a different set of significant explanatory or correlated variables. Our findings highlight the need to continue documenting and analysing channel response after floods at different locations and scales. Whereas this is key for a better process understanding, the identification of controlling factors can also contribute to the identification of critical reaches, which in turn is crucial for the forecasting and design of sound river basin management strategies.



Author(s):  
D. Prandle ◽  
E.R. Funke ◽  
N.L. Crookshank ◽  
R. Renner


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