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

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

[1]  N. Cheng,et al.  Bed‐Load Transport in Vegetated Flows: Phenomena, Parametrization, and Prediction , 2021, Water Resources Research.

[2]  H. Nepf,et al.  Impact of Stem Size on Turbulence and Sediment Resuspension Under Unidirectional Flow , 2021, Water Resources Research.

[3]  C. Tseng,et al.  A Two‐Layer Turbulence‐Based Model to Predict Suspended Sediment Concentration in Flows With Aquatic Vegetation , 2021, Geophysical Research Letters.

[4]  B. Norris,et al.  Relating millimeter‐scale turbulence to meter‐scale subtidal erosion and accretion across the fringe of a coastal mangrove forest , 2020, Earth Surface Processes and Landforms.

[5]  H. Nepf,et al.  Measured and Predicted Turbulent Kinetic Energy in Flow Through Emergent Vegetation With Real Plant Morphology , 2020, Water Resources Research.

[6]  H. Nepf,et al.  Turbulence and Bed Load Transport in Channels With Randomly Distributed Emergent Patches of Model Vegetation , 2020, Geophysical Research Letters.

[7]  H. Nepf,et al.  Turbulence and Particle Deposition Under Steady Flow Along a Submerged Seagrass Meadow , 2020 .

[8]  S. Darby,et al.  River bank instability from unsustainable sand mining in the lower Mekong River , 2020, Nature Sustainability.

[9]  A. Armanini,et al.  Bed-load through emergent vegetation , 2019, Advances in Water Resources.

[10]  H. Nepf,et al.  Impact of Vegetation on Bed Load Transport Rate and Bedform Characteristics , 2018, Water Resources Research.

[11]  Dylan B. Lee,et al.  Determining the scales of collective entrainment in collision-driven bed load , 2018, Earth Surface Dynamics.

[12]  Ryan J. Lowe,et al.  Predicting Bed Shear Stresses in Vegetated Channels , 2018, Water Resources Research.

[13]  H. Nepf,et al.  A Turbulence‐Based Bed‐Load Transport Model for Bare and Vegetated Channels , 2018, Geophysical Research Letters.

[14]  P. Diplas,et al.  A Unified Approach to Bed Load Transport Description Over a Wide Range of Flow Conditions via the Use of Conditional Data Treatment , 2018 .

[15]  R. Tinoco,et al.  Turbulence as the Main Driver of Resuspension in Oscillatory Flow Through Vegetation , 2018 .

[16]  B. Norris,et al.  The Effect of Pneumatophore Density on Turbulence: A Field Study in a Sonneratia-dominated Mangrove Forest, Vietnam , 2017 .

[17]  W. Nardin,et al.  Buried Alive or Washed Away The Challenging Life of Mangroves in the Mekong Delta , 2017 .

[18]  Ryan J. Lowe,et al.  A new model for predicting the drag exerted by vegetation canopies , 2017 .

[19]  N. Finnegan,et al.  Interplay between grain protrusion and sediment entrainment in an experimental flume , 2017 .

[20]  G. Coco,et al.  The influence of turbulent bursting on sediment resuspension under unidirectional currents , 2016 .

[21]  H. Nepf,et al.  The onset of sediment transport in vegetated channels predicted by turbulent kinetic energy , 2016 .

[22]  S. Kaya,et al.  Scour patterns around isolated vegetation elements , 2016 .

[23]  H. Nepf,et al.  Sediment deposition within and around a finite patch of model vegetation over a range of channel velocity , 2016 .

[24]  Qingjun Yang,et al.  Estimation of the bed shear stress in vegetated and bare channels with smooth beds , 2015 .

[25]  L. Sklar,et al.  When do plants modify fluvial processes? Plant‐hydraulic interactions under variable flow and sediment supply rates , 2015 .

[26]  M. Schmeeckle.  The role of velocity, pressure, and bed stress fluctuations in bed load transport over bed forms: numerical simulation downstream of a backward-facing step , 2014 .

[27]  M. Schmeeckle,et al.  The influence of vegetation on turbulence and bed load transport , 2013 .

[28]  S. Balachandar,et al.  Work-based criterion for particle motion and implication for turbulent bed-load transport , 2012 .

[29]  E. Cowen,et al.  A k–ε turbulence model based on the scales of vertical shear and stem wakes valid for emergent and submerged vegetated flows , 2012, Journal of Fluid Mechanics.

[30]  H. Nepf.  Flow and Transport in Regions with Aquatic Vegetation , 2012 .

[31]  V. Voller,et al.  Natural processes in delta restoration: application to the Mississippi Delta. , 2011, Annual review of marine science.

[32]  Chris J. Kennedy,et al.  The value of estuarine and coastal ecosystem services , 2011 .

[33]  Panayiotis Diplas,et al.  Impulse and particle dislodgement under turbulent flow conditions , 2010 .

[34]  A. Celik,et al.  The Role of Impulse on the Initiation of Particle Movement Under Turbulent Flow Conditions , 2008, Science.

[35]  Jeffrey Tsaros Rominger,et al.  Interaction between flow, transport and vegetation spatial structure , 2008 .

[36]  Yukie Tanino,et al.  Lateral dispersion in random cylinder arrays at high Reynolds number , 2008, Journal of Fluid Mechanics.

[37]  W. Dietrich,et al.  Is the critical Shields stress for incipient sediment motion dependent on channel‐bed slope? , 2007 .

[38]  Jørgen Fredsøe,et al.  Influence of turbulence on bed load sediment transport , 2003 .

[39]  U. Zanke,et al.  ON THE INFLUENCE OF TURBULENCE ON THE INITIATION OF SEDIMENT MOTION , 2003 .

[40]  Vladimir Nikora,et al.  Despiking Acoustic Doppler Velocimeter Data , 2002 .

[41]  Enrique R. Vivoni,et al.  Flow structure in depth-limited, vegetated flow , 2000 .

[42]  W. Graf.  Discussion of "Inception of Sediment Transport on Steep Slopes" , 2000 .

[43]  J. Damgaard,et al.  Inception of Sediment Transport on Steep Slopes , 2000 .

[44]  Richard Soulsby,et al.  Discussion of “Inception of Sediment Transport on Steep Slopes” by Richard J. S. Whitehouse, Richard L. Soulsby, and Jesper S. Damgaard , 2000 .

[45]  S. Pope.  Turbulent Flows: FUNDAMENTALS , 2000 .

[46]  D. Montgomery,et al.  A systematic analysis of eight decades of incipient motion studies, with special reference to gravel‐bedded rivers , 1997 .

[47]  R. O'Neill,et al.  The value of the world's ecosystem services and natural capital , 1997, Nature.

[48]  R. Soulsby.  Dynamics of marine sands : a manual for practical applications , 1997 .

[49]  Yarko Niño,et al.  Experiments on particle—turbulence interactions in the near–wall region of an open channel flow: implications for sediment transport , 1996, Journal of Fluid Mechanics.

[50]  M. C. Quick,et al.  Erosion and sedimentation , 1996 .

[51]  R. L. Shreve,et al.  Role of Near‐Bed Turbulence Structure in Bed Load Transport and Bed Form Mechanics , 1995 .

[52]  Steven R. Abt,et al.  Sediment Deposition and Entrapment in Vegetated Streambeds , 1994 .

[53]  R. L. Soulsby,et al.  Chapter 5 The Bottom Boundary Layer of Shelf Seas , 1983 .

[54]  A. V. Smol’yakov,et al.  Statistical Description of Turbulence , 1983 .

[55]  W. Dietrich.  Settling velocity of natural particles , 1982 .

[56]  R. Hallermeier,et al.  Terminal settling velocity of commonly occurring sand grains , 1981 .

[57]  Nicholas Kouwen,et al.  FLEXIBLE ROUGHNESS IN OPEN CHANNELS , 1973 .

[58]  J. Lumley,et al.  Turbulent Transport of Momentum and Heat , 1972 .

[59]  J. Lumley,et al.  A First Course in Turbulence , 1972 .

[60]  F. Engelund,et al.  A monograph on sediment transport in alluvial streams , 1967 .

[61]  H. Einstein,et al.  The Bed-Load Function for Sediment Transportation in Open Channel Flows , 1950 .

[62]  R. Müller,et al.  Formulas for Bed-Load transport , 1948 .

[63]  H. A. Einstein,et al.  Formulas for the Transportation of Bed Load , 1942 .

[64]  A. Shields,et al.  Anwendung der Aehnlichkeitsmechanik und der Turbulenzforschung auf die Geschiebebewegung , 1936 .

[65]  William Walden Rubey.  Settling velocity of gravel, sand, and silt particles , 1933 .

[66]  J. Leconte.  On some of the ancient glaciers of the sierras , 1873, American Journal of Science, and Arts.