A Turbulence-Based Bed-Load Transport Model for Bare and Vegetated Channels

J. Q. Yang, H. M. Nepf

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Previous studies have shown that sediment transport models based on bed shear stress (τ) are not accurate for regions with vegetation. The present study demonstrated that the inaccuracy arises from the influence of vegetation-generated turbulence. Bed-load transport rate, Qs, and near-bed velocity were measured in a sediment-recirculating flume with model vegetation of different vegetation volume fractions (ϕ) and with bare sand beds. At the same τ, the measured Qs increased with increasing ϕ, suggesting that vegetation-generated turbulence, which also increased with increasing ϕ, was augmenting the bed-load transport. At the same near-bed turbulent kinetic energy, kt, the Qs measured in both bare and vegetated channels agreed within uncertainty, suggesting that kt may be a more universal predictor of bed-load transport than bed shear stress. A τ-based bed-load transport model was reinterpreted as a kt-based model. The new kt-based model predicted the Qs measurements for both bare and vegetated channels.

Original languageEnglish (US)
Pages (from-to)10,428-10,436
JournalGeophysical Research Letters
Volume45
Issue number19
DOIs
StatePublished - Oct 16 2018
Externally publishedYes

Bibliographical note

Funding Information:
The authors thank Milani Chatterji-Len and Yinghao Zhang for their assistance with the experiments. We also thank John Trowbridge, Francesco Ballio, and another anonymous reviewer for their insightful comments. The work was supported by NSF grant EAR 1414499. Judy Q. Yang was supported by the Martin Family Society for Sustainability. The data in this study are tabulated in Judy Qingjun Yang's thesis, which will be available on MIT D-Space (https://dspace.mit.edu/).

Funding Information:
The authors thank Milani Chatterji-Len and Yinghao Zhang for their assistance with the experiments. We also thank John Trowbridge, Francesco Ballio, and another anonymous reviewer for their insightful comments. The work was supported by NSF grant EAR 1414499. Judy Q. Yang was supported by the Martin Family Society for Sustainability. The data in this study are tabulated in Judy Qingjun Yang’s thesis, which will be available on MIT D-Space (https://dspace.mit.edu/).

Keywords

  • bed shear stress
  • bed-load transport rate
  • erosion
  • sediment transport
  • turbulence
  • vegetation

Fingerprint Dive into the research topics of 'A Turbulence-Based Bed-Load Transport Model for Bare and Vegetated Channels'. Together they form a unique fingerprint.

Cite this