Plant Morphology Impacts Bedload Sediment Transport

Geophysical Research Letters, Год журнала: 2024, Номер 51(12)

Опубликована: Июнь 14, 2024

Abstract Bedload sediment transport plays an important role in the evolution of rivers, marshes and deltas. In these aquatic environments, vegetation is widespread, plant species have unique morphology. However, impact real morphology on flow has not been quantified. This study used model plants with morphology, based Phragmites australis , Acorus calamus Typha latifolia . The frontal area increases away from bed, which leads to higher near‐bed velocity than would be predicted depth‐average area. A coefficient was defined quantify vertically‐varied Laboratory experiments confirmed that improved prediction velocity, turbulent kinetic energy bedload rate canopies realistic Plant can alter rates by up order magnitude, relative assumption uniform

Язык: Английский

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Prediction of bedload transport inside vegetation canopies with natural morphology

Journal of Hydrodynamics, Год журнала: 2024, Номер 36(3), С. 556 - 569

Опубликована: Июнь 1, 2024

Язык: Английский

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Competing effects of vegetation density on sedimentation in deltaic marshes

Nature Communications, Год журнала: 2022, Номер 13(1)

Опубликована: Авг. 8, 2022

Abstract Marsh vegetation, a definitive component of delta ecosystems, has strong effect on sediment retention and land-building, controlling both how much can be delivered to is retained by the marsh. An understanding vegetation influences these processes would improve restoration management marshes. We use random displacement model simulate transport, deposition, resuspension within As density increases, velocity declines, which reduces supply marsh, but also resuspension, enhances The competing trends produce nonlinear relationship between sedimentation density, such that an intermediate yields maximum sedimentation. Two patterns spatial distribution emerge in simulation, exponential only occurs when absent. With farther into marsh uniform distribution. was validated with field observations response seasonal variation observed Mississippi River Delta.

Язык: Английский

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Predicting velocity and turbulent kinetic energy inside an emergent Phragmites australis canopy with real morphology

Environmental Fluid Mechanics, Год журнала: 2023, Номер 23(4), С. 943 - 963

Опубликована: Авг. 1, 2023

Язык: Английский

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Insights for River Restoration: The Impacts of Vegetation Canopy Length and Canopy Discontinuity on Riverbed Evolution

Water Resources Research, Год журнала: 2024, Номер 60(7)

Опубликована: Июль 1, 2024

Abstract River restoration projects often involve vegetation planting to retain sediment and stabilize riverbanks. Laboratory experiments have explored the impact of rigid emergent canopies on bed morphology. Inside canopies, erosion is attributed vegetation‐induced turbulent kinetic energy ( TKE ). Based in‐canopy local criteria for movement, a method established validated predicting length region. In bare channel, related ratio canopy flow adjustment distance, L / I , exhibits two trends. At < 1, maximum depth, d s ) length, region increase with increasing length. ≥ are not influenced by remain constant. vegetated regions same plant density, discontinuous (streamwise interval width D yield weaker than continuous canopies. The mutual influence between must be considered if satisfies 3 . These results provide insights designing river projects.

Язык: Английский

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Plants and river morphodynamics: The emergence of fluvial biogeomorphology

River Research and Applications, Год журнала: 2024, Номер 40(6), С. 887 - 942

Опубликована: Апрель 4, 2024

Abstract In this article, we track the evolution of fluvial biogeomorphology from middle 20th century to present. We consider emergence as an interdisciplinary research area that integrates knowledge drawn primarily geomorphology and plant ecology, but with inputs hydrology landscape ecology. start by assembling evidence for field a keyword search Web Science detailed analysis papers published in two scientific journals: journal—Earth Surface Processes Landforms; multidisciplinary river science journal—River Research Applications. Based on evidence, identify three distinct time periods development biogeomorphology: ‘early years’ before 1990; transitional decade 1990s; period rapid expansion diversification themes, methods investigation scales since 2000. Because literature is vast, can only summarize developments each these periods, refer recent in‐depth reviews conceptual perspectives relevant topics. Thus, rather than full deep review, present annotated bibliographic overview biogeomorphology, whereby text describes broad trends supported tables citations deliver greater detail. end brief consideration likely future developments.

Язык: Английский

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The thresholds of sediment resuspension within emergent vegetation under combined wave-current conditions – a flume experiment

Coastal Engineering, Год журнала: 2025, Номер unknown, С. 104727 - 104727

Опубликована: Фев. 1, 2025

Язык: Английский

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Velocity, Turbulence, and Sediment Deposition in a Channel Partially Filled With a Phragmites australis Canopy

Water Resources Research, Год журнала: 2022, Номер 58(8)

Опубликована: Авг. 1, 2022

Abstract Laboratory experiments examined the longitudinal evolution of near‐bed velocity, turbulent kinetic energy (TKE), and net deposition in a model Phragmites australis canopy occupying 1/3 channel width. The canopies were constructed from P . with real morphology solid volume fraction between 0.003 0.018. An exponential was modified to predict velocity inside canopy, which TKE can be predicted. By combining predicted probability, we proposed distribution canopy. TKE, good agreement measurements. Relative an upstream reference, within enhanced when two conditions met: in‐canopy, smaller than critical value for resuspension, resuspension took place bare channel. Above vegetation density (defined by ϕ c ), spatially‐averaged surpassed that adjacent provides way estimate always diminished over some flow adjustment distance, L d (distance leading edge fully developed flow). When length greater 0.4 , canopy‐averaged relative Finally, same length, differences plant morphologies did not have strong impact on in‐canopy distribution.

Язык: Английский

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Drag Coefficient of Emergent Vegetation in a Shallow Nonuniform Flow Over a Mobile Sand Bed

Water Resources Research, Год журнала: 2024, Номер 60(5)

Опубликована: Май 1, 2024

Abstract Widely distributed in natural rivers and coasts, vegetation interacts with fluid flows sediments a variable complicated manner. Such interactions make it difficult to predict associated drag forces during sediment transport. This paper investigates the coefficient for an emergent vegetated patch area under nonuniform flow mobile bed conditions, based on analytical model solving momentum equation following our previous work (Zhang et al., 2020, https://doi.org/10.1029/2020WR027613 ). Emergent was modeled rigid cylinders arranged staggered arrays of different coverage ∅. Laboratory flume tests were conducted measure variations both water surfaces along sand bed. Based experimental theoretical analyses, dimensionless integrating terms properties effects is proposed C d over The calculated values exhibit two trends, that is, nonmonotonically or monotonically increasing streamwise direction, due combined effect surface gradient slope. morphodynamic response manifests as evolution slope within patch. Ongoing scouring directs flow's energy toward overcoming rising slope, leading relatively stable stage low transport rate. study advances existing understanding coefficient's role flows. It also enhances applicability models riverine restoration.

Язык: Английский

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Turbulence Dictates Bedload Transport in Vegetated Channels Without Dependence on Stem Diameter and Arrangement

Geophysical Research Letters, Год журнала: 2021, Номер 48(21)

Опубликована: Окт. 17, 2021

Abstract Vegetation provides habitat and nature‐based solutions to coastal flooding erosion, drawing significant interest in its restoration, which requires an understanding of sediment transport retention. Laboratory experiments examined the influence stem diameter arrangement on bedload by considering arrays different mixed diameters. Bedload rate was observed depend turbulent kinetic energy, with no dependence diameter, shown be consistent impulse model for entrainment. Existing predictors bare beds, based bed shear stress, were recast terms turbulence. The new turbulence‐based predicted measured canopies across a range conditions drawn from several previous studies. A prediction turbulence biomass velocity also described, providing important step toward predicting real vegetation morphology.

Язык: Английский

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