Skip to main content

Research Repository

Advanced Search

What is suspended sediment?

Parsons, A.J.; Cooper, J.; Wainwright, J.

What is suspended sediment? Thumbnail


A.J. Parsons

J. Cooper


Suspended sediment is conventionally regarded as that sediment transported by a fluid that it is fine enough for turbulent eddies to outweigh settling of the particles through the fluid. Early work in the fluvial field attributed suspension to turbulence, and led to the notion of a critical threshold for maintaining sediment in suspension. However, research on both turbulence structures and the interactions between suspended sediment and bedforms in rivers has shown a more complex story and, although there appear to have been no studies of the impact of bedforms on aeolian suspended sediment concentrations, turbulent flow structures and transport rates of saltating particles have been shown to be affected. This research indicates that suspended sediment neither travels with the same velocity as the flow in which it is suspended, nor is it likely to remain in suspension in perpetuity, even under conditions of steady flow or in unsteady flow the where dimensionless critical threshold is permanently exceeded. Rather, like bedload, it travels in a series of hops, and is repeatedly deposited on the bed where it remains until it is re-entrained. Is there, therefore, a qualitative difference between suspended and saltating sediment, or is it just a quantitative difference in the size of the jump length and the frequency of re-entrainment? It is our contention that the distinction of suspension as a separate class of sediment transport is both arbitrary and an unhelpful anthropocentric artefact. If we recognize that sediment transport is a continuum and applies to any fluid medium rather than split into different “processes” based on arbitrary thresholds and fluids, then recognizing the continuity will enable development of an holistic approach sediment transport, and thus sediment-transport models that are likely to be viable across a wider range of conditions than hitherto. This article is protected by copyright. All rights reserved.


Parsons, A., Cooper, J., & Wainwright, J. (2015). What is suspended sediment?. Earth Surface Processes and Landforms, 40(10), 1417-1420.

Journal Article Type Article
Acceptance Date Mar 2, 2015
Online Publication Date Mar 3, 2015
Publication Date Aug 4, 2015
Deposit Date Mar 6, 2015
Publicly Available Date Mar 3, 2016
Journal Earth Surface Processes and Landforms
Print ISSN 0197-9337
Electronic ISSN 1096-9837
Publisher British Society for Geomorphology
Peer Reviewed Peer Reviewed
Volume 40
Issue 10
Pages 1417-1420
Keywords Suspended sediment, Turbulence, Virtual velocity.


Accepted Journal Article (402 Kb)

Copyright Statement
This is the accepted version of the following article: Parsons, A.J., Cooper, J. and Wainwright, J. (2015) 'What is suspended sediment?', Earth surface processes and landforms, 40(10): 1417-1420, which has been published in final form at This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.

You might also like

Downloadable Citations