Enhanced flow variability and morphological changes through individual wood placements on a gravel bed

Geomorphology, Journal Year: 2024, Volume and Issue: 453, P. 109135 - 109135

Published: March 4, 2024

To design and evaluate river restoration projects with wood, it is crucial to understand how the placement of wood will alter flow bed morphology. This information still missing. address this, flume experiments were conducted a single log placed on mobile uniform grain size. The effect diameter, orientation flow, length variability morphology was studied for various initial conditions. Even increased variability, herein defined as spatial in both velocity turbulent kinetic energy. For each at channel center, logs generated symmetric scour pattern alongside downstream due shear turbulence by log. A steady, adjusted cross-section reached cessation erosion, which occurred when stress decreased below critical velocity. Logs larger diameter tended erode more deeply, so that final, similar different dimensions. Changes topography affected wake characteristics. small changes longer zones reduced velocity, can increase residence time organic matter or nutrients region. big created deepest longest holes, may locally reduce stream temperature improve fish habitat during summer.

Language: Английский

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A Simple Approach to Simulate Logjams in Two-Dimensional Hydrodynamic Models

Journal of Hydraulic Engineering, Journal Year: 2024, Volume and Issue: 150(4)

Published: April 8, 2024

Natural accumulations of wood, as well engineered logjams, are relevant for river ecosystems. These structures, by interacting with the flow, can lead to significant backwater effects and morphological changes. Research on logjams has so far mainly relied physical modeling, which may impede study different flow conditions or logjam designs configurations. Here, a simple approach simulation in two-dimensional depth-averaged hydrodynamic solvers is explored, building widely available modeling options. The effect included combining local contraction an increase frictional losses based characteristics, thereby reflecting main processes region near logjam. More than 350 tests were used calibrate validate proposed approach. For all tests, rise due channel- partial-spanning be estimated ±30% prediction range. Given its design, calibrated model not universal requires careful evaluation when applying it setups. Nevertheless, clear advantage that uses tools adopted most standard solvers.

Language: Английский

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Magnetic properties of sediments within the water-level fluctuation zone of the Three Gorges Reservoir and their response to provenance and hydrodynamic conditions

Journal of Soils and Sediments, Journal Year: 2024, Volume and Issue: 24(6), P. 2548 - 2563

Published: May 28, 2024

Language: Английский

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A review of flash flood hazards influenced by various solid material sources in mountain environment

Progress in Physical Geography Earth and Environment, Journal Year: 2024, Volume and Issue: 48(5-6), P. 781 - 800

Published: Sept. 6, 2024

Solid material sources, such as sediment, large wood, and vehicles, intensify flash flood hazards. This paper provides a detailed review of processes involving the recruitment, entrainment, transport, blockage dynamics various solid sources. Results indicate that sediment supplied by like landslides debris flows can obstruct river channels, leading to sudden increase in levels. The failure barrier dam results an expansion downstream inundation areas. Large wood floating vehicles transported floods may directly impact destroy built structures or form blockages at structures. Blockages lead backwater rise, amplification flow during these causes more severe disasters. Based on analyses, proposes future research directions primarily focusing changes burial caused sheltering effects building groups. Furthermore, study aims investigate vehicle blockage.

Language: Английский

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Effects of logjams on river hydrodynamics under inundation conditions

Journal of Hydrodynamics, Journal Year: 2024, Volume and Issue: 36(4), P. 757 - 771

Published: Aug. 1, 2024

Language: Английский

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