A Review on Bank Retreat: Mechanisms, Observations, and Modeling
A Review on Bank Retreat: Mechanisms, Observations, and Modeling
Bank retreat plays a fundamental role in fluvial and estuarine dynamics. It affects the cross-sectional evolution of channels, provides a source of sediment, and modulates the diversity of habitats. Understanding and predicting the geomorphological response of fluvial/tidal channels to external driving forces underpins the robust management of water courses and the protection of wetlands. Here, we review bank retreat with respect to mechanisms, observations, and modeling, covering both rivers and (previously neglected) tidal channels. Our review encompasses both experimental and in situ observations of failure mechanisms and bank retreat rates, modeling approaches and numerical methods to simulate bank erosion. We identify that external forces, despite their distinct characteristics, may have similar effects on bank stability in both river and tidal channels, leading to the same failure mode. We review existing data and empirical functions for bank retreat rate across a range of spatial and temporal scales, and highlight the necessity to account for both hydraulic and geotechnical controls. Based on time scale considerations, we propose a new hierarchy of modeling styles that accounts for bank retreat, leading to clear recommendations for enhancing existing modeling approaches. Finally, we discuss systematically the feedbacks between bank retreat and morphodynamics, and suggest that to move this agenda forward will require a better understanding of multifactor-driven bank retreat across a range of temporal scales, with particular attention to the differences (and similarities) between riverine and estuarine environments, and the role of feedbacks exerted by the collapsed bank soil.
bank erosion and collapse, failure mechanism, fluvial and tidal environments, morphodynamics, slump blocks
Zhao, Kun
68779f85-b646-485f-a724-1c8100cfd442
Coco, Giovanni
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Gong, Zheng
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Darby, Stephen
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Lanzoni, Stefano
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Xu, Fan
a74a50aa-98c4-4457-a767-f0fe8820c535
Zhang, Kaili
c8b886a5-ea0d-4e2b-8f76-2ea0c7c63aed
Townend, Ian
f72e5186-cae8-41fd-8712-d5746f78328e
8 June 2022
Zhao, Kun
68779f85-b646-485f-a724-1c8100cfd442
Coco, Giovanni
8a6c97e1-2a44-4f03-ad8d-e03dbc2908db
Gong, Zheng
dc27f817-ec1c-4e7b-97bc-8b6e91ab6205
Darby, Stephen
4c3e1c76-d404-4ff3-86f8-84e42fbb7970
Lanzoni, Stefano
d595f2ee-ab1a-448d-b114-a47e4874bc81
Xu, Fan
a74a50aa-98c4-4457-a767-f0fe8820c535
Zhang, Kaili
c8b886a5-ea0d-4e2b-8f76-2ea0c7c63aed
Townend, Ian
f72e5186-cae8-41fd-8712-d5746f78328e
Zhao, Kun, Coco, Giovanni, Gong, Zheng, Darby, Stephen, Lanzoni, Stefano, Xu, Fan, Zhang, Kaili and Townend, Ian
(2022)
A Review on Bank Retreat: Mechanisms, Observations, and Modeling.
Reviews of Geophysics, 60 (2), [e2021RG000761].
(doi:10.1029/2021RG000761).
Abstract
Bank retreat plays a fundamental role in fluvial and estuarine dynamics. It affects the cross-sectional evolution of channels, provides a source of sediment, and modulates the diversity of habitats. Understanding and predicting the geomorphological response of fluvial/tidal channels to external driving forces underpins the robust management of water courses and the protection of wetlands. Here, we review bank retreat with respect to mechanisms, observations, and modeling, covering both rivers and (previously neglected) tidal channels. Our review encompasses both experimental and in situ observations of failure mechanisms and bank retreat rates, modeling approaches and numerical methods to simulate bank erosion. We identify that external forces, despite their distinct characteristics, may have similar effects on bank stability in both river and tidal channels, leading to the same failure mode. We review existing data and empirical functions for bank retreat rate across a range of spatial and temporal scales, and highlight the necessity to account for both hydraulic and geotechnical controls. Based on time scale considerations, we propose a new hierarchy of modeling styles that accounts for bank retreat, leading to clear recommendations for enhancing existing modeling approaches. Finally, we discuss systematically the feedbacks between bank retreat and morphodynamics, and suggest that to move this agenda forward will require a better understanding of multifactor-driven bank retreat across a range of temporal scales, with particular attention to the differences (and similarities) between riverine and estuarine environments, and the role of feedbacks exerted by the collapsed bank soil.
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e-pub ahead of print date: 7 June 2022
Published date: 8 June 2022
Additional Information:
Funding Information:
This research was supported by the National Natural Science Foundation of China (51925905), the China Postdoctoral Science Foundation (2021M701050), the Fundamental Research Funds for the Central Universities (B220202079), and the National Natural Science Foundation of China (51879095). The authors acknowledge valuable comments from Sebastien Carretier, Simona Francalanci, and one anonymous reviewer and the managing editors, which led to significant improvement of the paper. Special thanks are given to Qingyun Duan and Pei Xin, who provide suggestions for the structure and revision of this review. Additional thanks go to Yanyan Kang for her help on Figure 14.
Funding Information:
This research was supported by the National Natural Science Foundation of China (51925905), the China Postdoctoral Science Foundation (2021M701050), the Fundamental Research Funds for the Central Universities (B220202079), and the National Natural Science Foundation of China (51879095). The authors acknowledge valuable comments from Sebastien Carretier, Simona Francalanci, and one anonymous reviewer and the managing editors, which led to significant improvement of the paper. Special thanks are given to Qingyun Duan and Pei Xin, who provide suggestions for the structure and revision of this review. Additional thanks go to Yanyan Kang for her help on Figure 14 . a b c d A chunk A d 2 60 A i 2 B c B b c c r CEI C s D D f E m E l E v 3 E a 2 F s F R F D F w g 2 H b H c H p H t H ub H w i i c K l 3 K w K s K sat l t l c P P c P ic P w P s Q s Q l Q c q b 2 r l S t t b U U c U d u w u a V s 3 V g 3 W w t w c b z l α β η θ ε σ σ c σ t τ τ b τ c λ λ b φ φ b ω γ b Apparent cohesion Angle of repose Bank stratification Cohesive Drainage area Dry granular flow Effective internal friction angle Effective soil cohesion Elastic‐plastic model Elastic potential energy Evapotranspiration Evaporation Fluidization Gully erosion Headcuts Hydraulic conductivity Hydraulic head Infiltration Inner bank Internal friction angle Matric suction Mechanical fatigue Mohr‐Coulomb failure criterion Normal stress Outer bank Perched water table Plunge pool erosion Root cohesion Shear strength Shear stress Soil cohesion Soil desiccation Soil diffusivity Soil dispersion Soil permeability Static liquefaction Stemflow Subaerial process Tensile strength Tensile stress Tension crack Undercutting Weathering
Publisher Copyright:
© 2022. The Authors.
Keywords:
bank erosion and collapse, failure mechanism, fluvial and tidal environments, morphodynamics, slump blocks
Identifiers
Local EPrints ID: 458025
URI: http://eprints.soton.ac.uk/id/eprint/458025
ISSN: 8755-1209
PURE UUID: 8d7cd83e-3c92-4100-9391-ebea52b9742f
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Date deposited: 27 Jun 2022 16:36
Last modified: 17 Mar 2024 02:54
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Contributors
Author:
Kun Zhao
Author:
Giovanni Coco
Author:
Zheng Gong
Author:
Stefano Lanzoni
Author:
Fan Xu
Author:
Kaili Zhang
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