Numerical simulation of hydrodynamics and bank erosion in a river bend

Rinaldi, Massimo; Mengoni, Beatrice; Luppi, Laura; Darby, Stephen E.; Mosselman, E.

doi:10.1029/2008wr007008

Cited by 204 publications

(152 citation statements)

References 48 publications

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“…It has been difficult to perform detailed and fast mapping of riverbank vegetation cover on vertical banks. Although vegetation is an important determinant of the evolution of river channels and riverbanks, some modeling studies still do not fully consider vegetation in riverine environments [69]. Capture of vegetation classes and changes in vegetation will allow for the incorporation of variables for erosion rates into models.…”

Section: Discussionmentioning

confidence: 99%

Area-Based Approach for Mapping and Monitoring Riverine Vegetation Using Mobile Laser Scanning

et al. 2013

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Vegetation plays an important role in stabilizing the soil and decreasing fluvial erosion. In certain cases, vegetation increases the accumulation of fine sediments. Efficient and accurate methods are required for mapping and monitoring changes in the fluvial environment. Here, we develop an area-based approach for mapping and monitoring the vegetation structure along a river channel. First, a 2 × 2 m grid was placed over the study area. Metrics describing vegetation density and height were derived from mobile laser-scanning (MLS) data and used to predict the variables in the nearest-neighbor (NN) estimations. The training data were obtained from aerial images. The vegetation cover type was classified into the following four classes: bare ground, field layer, shrub layer, and canopy layer. Multi-temporal MLS data sets were applied to the change detection of riverine vegetation. This approach successfully classified vegetation cover with an overall classification accuracy of 72.6%; classification accuracies for bare ground, field layer, OPEN ACCESSRemote Sens. 2013, 5 5286 shrub layer, and canopy layer were 79.5%, 35.0%, 45.2% and 100.0%, respectively. Vegetation changes were detected primarily in outer river bends. These results proved that our approach was suitable for mapping riverine vegetation.

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Section: Discussionmentioning

confidence: 99%

Area-Based Approach for Mapping and Monitoring Riverine Vegetation Using Mobile Laser Scanning

et al. 2013

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“…Another, more recent modeling strategy involves two-and three-dimensional computational fluid dynamics [e.g., Shimizu et al, 1990;Ferguson et al, 2003;Duan and Julien, 2005;Ruther and Olsen, 2007]. These numerical flow simulations have been coupled with models of bed material transport [e.g., Li et al, 2008;Vasquez et al, 2008] and bank erosion [e.g., Mosselman, 1998;Darby et al, 2002;Rinaldi et al, 2008] as a means of predicting the evolution of channel form [e.g., Fischer-Antze et al, 2008].…”

Section: Introductionmentioning

confidence: 99%

Effect of point bar development on the local force balance governing flow in a simple, meandering gravel bed river

2011

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[1] The patterns of depth, velocity, and shear stress that direct a river's morphologic evolution are governed by a balance of forces. Analyzing these forces, associated with pressure gradients, boundary friction, channel curvature, and along-and across-stream changes in fluid momentum driven by bed topography, can yield insight regarding the establishment and maintenance of stable channel forms. This study examined how components of the local force balance changed as a meandering channel evolved from a simple, flat-bedded initial condition to a more complex bar-pool morphology. A numerical flow model, constrained by measurements of velocity and water surface elevation, characterized the flow field for four time periods bracketing two floods. For each time increment, runs were performed for discharges up to bankfull, and individual force balance components were computed from model output. Formation and growth of point bars enhanced topographic steering effects, which were of similar magnitude to the pressure gradient and centrifugal forces. Convective accelerations induced by the bar reduced the cross-stream pressure gradient, intensified flow toward the outer bank, and routed sediment around the upstream end of the bar. Adjustments in the flow field thus served to balance streamwise transport along the inner bank onto the bar and cross-stream transport into the pool. Even in the early stages of bar development, topographically driven spatial gradients in velocity played a significant role in the force balance at flows up to bankfull, altering the orientation of the shear stress and sediment transport to drive bar growth.Citation: Legleiter, C. J., L. R. Harrison, and T. Dunne (2011), Effect of point bar development on the local force balance governing flow in a simple, meandering gravel bed river,

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“…Following this line, most of the models which address the morphological evolution of the rivers couple hydrodynamic and bed evolution submodels with a bank erosion submodel, so they are able to predict changes in both bed and bank form, comprehending also bank failure (e.g., [28][29][30][31][32][33][34][35][36][37]). Nevertheless, their approach can differ significantly from one another.…”

Section: Introductionmentioning

confidence: 99%

“…Some authors, for example, conduct a proper bank stability investigation, considering a limit equilibrium analysis for planar or rotational slip failure [29,30] or a cantilever failure [30]. Others evaluate a bank erosion/accretion rate, which gives rise to the displacement of bank top and a consequent mesh modification [31,32,[35][36][37] or, in a similar way, they couple a bed scouring with an intermittent bank erosion model, which shift the bank while keeping the same initial angle of repose [28].…”

Section: Introductionmentioning

confidence: 99%

Numerical Modelling of Cohesive Bank Migration

Bosa

Petti

Pascolo

2018

Water

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River morphological evolution is a challenging topic, involving hydrodynamic flow, sediment transport and bank stability. Lowland rivers are often characterized by the coexistence of granular and cohesive material, with significantly different behaviours. This paper presents a bidimensional morphological model to describe the evolution of the lower course of rivers, where there are both granular and cohesive sediments. The hydrodynamic equations are coupled with two advection-diffusion equations, which consider the transport of granular and cohesive suspended sediment concentration separately. The change of bed height is evaluated as the sum of the contributions of granular and sediment material. A bank failure criterion is developed and incorporated into the numerical simulation of the hydrodynamic flood wave and channel evolution, to describe both bed deformation and bank recession. To this aim, two particular mechanisms are considered: the former being a lateral erosion due to the current flow and consequent cantilever collapse and the latter a geostatic failure due to the submergence. The equation system is integrated by means of a finite volume scheme. The resulting model is applied to the Tagliamento River, in northern Italy, where the meander migration is documented through a sequence of aerial images. The channel evolution is simulated, imposing an equivalent hydrograph consisting of a sequence of flood waves, which represents a medium year, with reference to their effect on sediment transport. The results show that the model adequately describes the general morphological evolution of the meander.

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Numerical simulation of hydrodynamics and bank erosion in a river bend

Cited by 204 publications

References 48 publications

Area-Based Approach for Mapping and Monitoring Riverine Vegetation Using Mobile Laser Scanning

Area-Based Approach for Mapping and Monitoring Riverine Vegetation Using Mobile Laser Scanning

Effect of point bar development on the local force balance governing flow in a simple, meandering gravel bed river

Numerical Modelling of Cohesive Bank Migration

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