Suspended load transport

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Definition of Suspended load transport:
The total amount (in kg) of sediment particles carried in suspension by the flow that pass through a plane in one unit time.
This is the common definition for Suspended load transport, other definitions can be discussed in the article
Particles in the water column of a turbulent flow can be carried over long distances as long as the net balance between upward suspending forces and gravity remains positive. The suspension capacity is the maximum amount which can be carried by a turbulent flow and depends on the energetic balance between buoyancy and gravity.

Sediment concentration profiles typically show a two-layer structure:

  • Dilute suspension transport layer: Far enough from the bottom, i.e. in the outer layer, the turbulence is fully-developed and the concentrations are low, typically smaller than 0.1%, corresponding to dilute conditions
  • High-concentrated (HC) suspension transport layer: The inner layer above the bottom is characterized by low-Reynolds conditions (developing turbulence) and high concentrations. Since the inner layer usually is thin (of the order of a few centimetres), it often falls outside the depth range where measurements are collected, and therefore largely remains undetected and little known. It comprises both the bed load and the sheet flow conditions for sand. Analysis of flume data suggests that particles are also kept in suspension by additional turbulence generated in the wake of the particles, which respond slower to the turbulent movements of the ambient water due to their inertia.

The transport capacity of the outer layer is controlled by that of the inner layer.

Related articles

Sediment transport formulas for the coastal environment
Sand transport
Manual Sediment Transport Measurements in Rivers, Estuaries and Coastal Seas
Sediment deposition and erosion processes
Dynamics of mud transport

The main authors of this article are Toorman, Erik and Berlamont, Jean
Please note that others may also have edited the contents of this article.

Citation: Toorman, Erik; Berlamont, Jean; (2024): Suspended load transport. Available from [accessed on 24-07-2024]