Comparison of Linear and Nonlinear Models for Cohesive Sediment Detachment: Rill Erosion, Hole Erosion Test, and Streambank Erosion Studies

Khanal, Anish; Klavon, Kate Riis; Fox, Garey A.; Daly, E. R.

doi:10.1061/(asce)hy.1943-7900.0001147

Cited by 27 publications

(30 citation statements)

References 39 publications

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“… D r = q s ). Equation typically assumes a linear relationship ( b = 1) between applied shear stress ( τ ) and sediment detachment rate once τ c has been exceeded (Khanal et al, ). The total shear stress ( τ ) acting on the surface is:

τ = italicρgRS

where ρ is the density of water, g is the gravitational acceleration constant, R is the hydraulic radius (generally taken to be the flow depth), and S is the sine of the surface slope.…”

Section: Discussionmentioning

confidence: 99%

“…Measurement techniques that use greater applied shear stress illustrate the nonlinear behavior of cohesive sediment detachment at higher applied shear stress. The Wilson model was shown to be an appropriate erosion rate model across the wider range observed when rill erodibility tests, hole erosion tests, and jet erosion tests are combined (Khanal et al, ).…”

Section: Discussionmentioning

confidence: 99%

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Sediment detachment and transport processes associated with internal erosion of soil pipes

Wilson

Wells

Kuhnle

et al. 2017

Earth Surf Processes Landf

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Subsurface flow can be an important process in gully erosion through its impact on decreasing soil cohesion and erosion resistance as soil water content or pressure increases and more directly by the effects of seepage forces on particle detachment and piping. The development of perched water tables fosters lateral flow that can result in seepage at the surface and/or formation of soil pipes by internal erosion of preferential flow paths. Continued internal erosion of soil pipes can lead to gullies, dam and levee failures. However, the processes involved in particle and aggregate detachment from soil pipe walls and transport processes within soil pipes have not been well studied or documented. This paper reviews the limited research on sediment detachment and transport in macropores and soil pipes and applies the knowledge learned from the much more extensive studies conducted on streams and industrial pipes to hydrogeologic conditions of soil pipes. Knowledge gaps are identified and recommendations are made for future research on sediment detachment and transport in soil pipes. Copyright © 2017 John Wiley & Sons, Ltd.

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τ = italicρgRS

where ρ is the density of water, g is the gravitational acceleration constant, R is the hydraulic radius (generally taken to be the flow depth), and S is the sine of the surface slope.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Sediment detachment and transport processes associated with internal erosion of soil pipes

Wilson

Wells

Kuhnle

et al. 2017

Earth Surf Processes Landf

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“…The under prediction of lateral retreat by the excess shear stress model can be attributed to the increase in applied τ around the outside of the meander located at the IL-BF site that is not correctly accounted for in the model. Previous research has shown that the Wilson model predicted lower lateral retreat closer to the observed retreat than the excess shear stress model when integrated into the Bank Stability and Toe Erosion Model (BSTEM) [45]. This was not the case when the Wilson model was incorporated into CONCEPTS for IL-BF.…”

Section: Implications For Lateral Retreat Predictionmentioning

confidence: 83%

“…For the IL-BF simulations, only the erodibility parameters for the silt layer were adjusted. Wilson model parameters for the gravel layer were determined by Khanal et al [45]. For simulations on FC-FM, only the erodibility parameters for the sand layer were adjusted.…”

Section: Streambank Erosion Predictionmentioning

confidence: 99%

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Watershed Variability in Streambank Erodibility and Implications for Erosion Prediction

Enlow

Fox

Guertault

2017

Water

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Abstract:Two fluvial erosion models are commonly used to simulate the erosion rate of cohesive soils: the empirical excess shear stress model and the mechanistic Wilson model. Both models include two soil parameters, the critical shear stress (τ c ) and the erodibility coefficient (k d ) for the excess shear stress model and b 0 and b 1 for the Wilson model. Jet erosion tests (JETs) allow for in-situ determination of these parameters. JETs were completed at numerous sites along two streams in each the Illinois River and Fort Cobb Reservoir watersheds. The objectives were to use JET results from these streambank tests to investigate variability of erodibility parameters on the watershed scale and investigate longitudinal trends in streambank erodibility. The research also determined the impact of this variability on lateral retreat predicted by a process-based model using both the excess shear stress model and the Wilson model. Parameters derived from JETs were incorporated into a one-dimensional process-based model to simulate bank retreat for one stream in each watershed. Erodibility parameters varied by two to five and one to two orders of magnitude in the Illinois River watershed and Fort Cobb Reservoir watershed, respectively. Less variation was observed in predicted retreat by a process-based model compared to the input erodibility parameters. Uncalibrated erodibility parameters and simplified applied shear stress estimates failed to match observed lateral retreats suggesting the need for model calibration and/or advanced flow modeling.

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Evaluating a process‐based model for use in streambank stabilization: insights on the Bank Stability and Toe Erosion Model (BSTEM)

Klavon

Fox

Guertault

et al. 2016

Earth Surf Processes Landf

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Streambank retreat is a complex cyclical process involving subaerial processes, fluvial erosion, seepage erosion, and geotechnical failures and is driven by several soil properties that themselves are temporally and spatially variable. Therefore, it can be extremely challenging to predict and model the erosion and consequent retreat of streambanks. However, modeling streambank retreat has many important applications, including the design and assessment of mitigation strategies for stream revitalization and stabilization. In order to highlight the current complexities of modeling streambank retreat and to suggest future research areas, this paper reviewed one of the most comprehensive streambank retreat models available, the Bank Stability and Toe Erosion Model (BSTEM), which has recently been integrated with several popular hydrodynamic and sediment transport models including the Hydrologic Engineering Centerˈs River Analysis System (HEC-RAS). The objectives of this paper were to: (i) comprehensively review studies that have utilized BSTEM and report their findings, (ii) address the limitations of the model so that it can be applied appropriately in its current form, and (iii) suggest directions of research that will help make the model a more useful tool in future applications. The paper includes an extensive overview of peer reviewed studies to guide future users of BSTEM. The review demonstrated that the model needs further testing and evaluation outside of the central United States. Also, further development is needed in terms of accounting for spatial and temporal variability in geotechnical and fluvial erodibility parameters, incorporating subaerial processes, and accounting for the influence of riparian vegetation on streambank pore-water pressure dynamics, applied shear stress, and erodibility parameters.

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Comparison of Linear and Nonlinear Models for Cohesive Sediment Detachment: Rill Erosion, Hole Erosion Test, and Streambank Erosion Studies

Cited by 27 publications

References 39 publications

Sediment detachment and transport processes associated with internal erosion of soil pipes

Sediment detachment and transport processes associated with internal erosion of soil pipes

Watershed Variability in Streambank Erodibility and Implications for Erosion Prediction

Evaluating a process‐based model for use in streambank stabilization: insights on the Bank Stability and Toe Erosion Model (BSTEM)

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