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Numerical study on river bar response to spatial variations of channel width. / Duró, Gonzalo; Crosato, Alessandra; Tassi, Pablo.

In: Advances in Water Resources, Vol. 93, No. Part A, 01.07.2016, p. 21-38.

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Duró, Gonzalo ; Crosato, Alessandra ; Tassi, Pablo. / Numerical study on river bar response to spatial variations of channel width. In: Advances in Water Resources. 2016 ; Vol. 93, No. Part A. pp. 21-38.

BibTeX

@article{3f17d70e16594737a4583a6c665fbe1b,
title = "Numerical study on river bar response to spatial variations of channel width",
abstract = "Managing river bar formation in alluvial channels remains a challenging issue related to the need to free intakes, improve navigation and optimise river restoration works. This work studies the effects of locally varying the channel width on bar formation to see whether channel widening and narrowing could be feasible bar control measures. The investigation focuses on steady (hybrid) bars, the most common type of bars in lowland rivers. Several numerical experiments are performed using a two-dimensional physics-based finite-difference code. Model simplifications include capacity-limited sediment transport, uniform grain size and constant discharge. Previous tests on field and experimental data show that the simulations of the relevant processes are realistic. The results indicate that the formation of steady alternate bars downstream of lateral structures occurs at a distance that depends on the local width reduction and that narrowing the channel for a distance of 10 times the original width appears sufficient to locally suppress alternate bars. A symmetric inflow forces the formation of symmetric bed topography, as for instance a flat bed or central bars. Similarly, an asymmetric inflow forces asymmetric bed topography, as alternate bars. Upstream flow asymmetries disrupt the symmetry of central bars leading to a compound bed configuration characterised by a dominant wandering channel, a common feature in wide lowland rivers. Central and alternate bars are found to coexist even if bar stability theories predict the development of alternate bars only. These results are promising and raise fundamental questions, but need experimental and field confirmation.",
keywords = "Channel narrowing, Channel widening, Numerical modelling, River bars, River channel width, River morphodynamics",
author = "Gonzalo Dur{\'o} and Alessandra Crosato and Pablo Tassi",
year = "2016",
month = "7",
day = "1",
doi = "10.1016/j.advwatres.2015.10.003",
language = "English",
volume = "93",
pages = "21--38",
journal = "Advances in Water Resources",
issn = "0309-1708",
publisher = "Elsevier",
number = "Part A",

}

RIS

TY - JOUR

T1 - Numerical study on river bar response to spatial variations of channel width

AU - Duró, Gonzalo

AU - Crosato, Alessandra

AU - Tassi, Pablo

PY - 2016/7/1

Y1 - 2016/7/1

N2 - Managing river bar formation in alluvial channels remains a challenging issue related to the need to free intakes, improve navigation and optimise river restoration works. This work studies the effects of locally varying the channel width on bar formation to see whether channel widening and narrowing could be feasible bar control measures. The investigation focuses on steady (hybrid) bars, the most common type of bars in lowland rivers. Several numerical experiments are performed using a two-dimensional physics-based finite-difference code. Model simplifications include capacity-limited sediment transport, uniform grain size and constant discharge. Previous tests on field and experimental data show that the simulations of the relevant processes are realistic. The results indicate that the formation of steady alternate bars downstream of lateral structures occurs at a distance that depends on the local width reduction and that narrowing the channel for a distance of 10 times the original width appears sufficient to locally suppress alternate bars. A symmetric inflow forces the formation of symmetric bed topography, as for instance a flat bed or central bars. Similarly, an asymmetric inflow forces asymmetric bed topography, as alternate bars. Upstream flow asymmetries disrupt the symmetry of central bars leading to a compound bed configuration characterised by a dominant wandering channel, a common feature in wide lowland rivers. Central and alternate bars are found to coexist even if bar stability theories predict the development of alternate bars only. These results are promising and raise fundamental questions, but need experimental and field confirmation.

AB - Managing river bar formation in alluvial channels remains a challenging issue related to the need to free intakes, improve navigation and optimise river restoration works. This work studies the effects of locally varying the channel width on bar formation to see whether channel widening and narrowing could be feasible bar control measures. The investigation focuses on steady (hybrid) bars, the most common type of bars in lowland rivers. Several numerical experiments are performed using a two-dimensional physics-based finite-difference code. Model simplifications include capacity-limited sediment transport, uniform grain size and constant discharge. Previous tests on field and experimental data show that the simulations of the relevant processes are realistic. The results indicate that the formation of steady alternate bars downstream of lateral structures occurs at a distance that depends on the local width reduction and that narrowing the channel for a distance of 10 times the original width appears sufficient to locally suppress alternate bars. A symmetric inflow forces the formation of symmetric bed topography, as for instance a flat bed or central bars. Similarly, an asymmetric inflow forces asymmetric bed topography, as alternate bars. Upstream flow asymmetries disrupt the symmetry of central bars leading to a compound bed configuration characterised by a dominant wandering channel, a common feature in wide lowland rivers. Central and alternate bars are found to coexist even if bar stability theories predict the development of alternate bars only. These results are promising and raise fundamental questions, but need experimental and field confirmation.

KW - Channel narrowing

KW - Channel widening

KW - Numerical modelling

KW - River bars

KW - River channel width

KW - River morphodynamics

UR - http://www.scopus.com/inward/record.url?scp=84960824953&partnerID=8YFLogxK

U2 - 10.1016/j.advwatres.2015.10.003

DO - 10.1016/j.advwatres.2015.10.003

M3 - Article

VL - 93

SP - 21

EP - 38

JO - Advances in Water Resources

T2 - Advances in Water Resources

JF - Advances in Water Resources

SN - 0309-1708

IS - Part A

ER -

ID: 25287346