EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Have we misunderstood the Shields curve?

Orencio Duran Vinent1 and Thomas Pähtz2
Orencio Duran Vinent and Thomas Pähtz
  • 1Texas A&M University, Ocean Engineering, College Station, United States of America (
  • 2Institute of Port, Coastal and Offshore Engineering, Ocean College, Zhejiang University, 310058 Hangzhou, China (

The Shields curve, which compiles measurements of fluvial sediment transport thresholds in terms of the nondimensionalized threshold fluid shear stress and shear Reynolds number, is a standard reference in geophysics and hydraulic and coastal engineering and commonly thought to describe the critical flow conditions that are required for flow-driven entrainment of bed sediment. However, recent findings from several independent research groups have challenged this belief on various grounds: (i) particle-bed impacts predominately trigger sediment entrainment [1]; (ii) such impact-triggered entrainment can sustain continuous transport even when flow-driven entrainment events are (almost) completely absent [2, 3, (4)]; and (iii) extrapolating measurements of the transport rate of such impact-sustained continuous transport to zero yields transport thresholds that still fall on the Shields curve [5]. The question that thus emerges from these findings is, if not flow-driven entrainment, then what is the physics behind the thresholds shown in the Shields curve? We will try to give an answer to this question based on our latest research.


[1] Vowinckel et al., Journal of Hydraulic Research, 2016, doi: 10.1080/00221686.2016.1140683

[2] Pähtz & Duran, Physical Review Fluids, 2017, doi: 10.1103/PhysRevFluids.2.074303

[3] Lee & Jerolmack, Earth Surface Dynamics, doi: 10.5194/esurf-6-1089-2018

[4] Heyman et al., Journal of Geophysical Research: Earth Surface, 2016, doi: 10.1002/2015JF003672

How to cite: Duran Vinent, O. and Pähtz, T.: Have we misunderstood the Shields curve?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2218,, 2020


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