Using particle‐scale simulations of nonsuspended sediment transport for a large range of Newtonian fluids driving transport, including air and water, we determine the bulk transport cessation threshold normalΘtr by extrapolating the transport load as a function of the dimensionless fluid shear stress (Shields number) Θ to the vanishing transport limit. In this limit, the simulated steady states of continuous transport can be described by simple analytical model equations relating the average transport layer properties to the law of the wall flow velocity profile. We use this model to calculate normalΘtr for arbitrary environments and derive a general Shields‐like threshold diagram in which a Stokes‐like number replaces the particle Reynolds number. Despite the simplicity of our hydrodynamic description, the predicted cessation threshold, both from the simulations and analytical model, quantitatively agrees with measurements for transport in air and viscous and turbulent liquids despite not being fitted to these measurements. We interpret the analytical model as a description of a continuous rebound motion of transported particles and thus normalΘtr as the minimal fluid shear stress needed to compensate the average energy loss of transported particles during an average rebound at the bed surface. This interpretation, supported by simulations near normalΘtr, implies that entrainment mechanisms are needed to sustain transport above normalΘtr. While entrainment by turbulent events sustains intermittent transport, entrainment by particle‐bed impacts sustains continuous transport. Combining our interpretations with the critical energy criterion for incipient motion by Valyrakis and coworkers, we put forward a new conceptual picture of sediment transport intermittency.

Predicting the morphodynamics of sedimentary landscapes due to fluvial and aeolian flows requires answering the following questions: Is the flow strong enough to initiate sediment transport, is the flow strong enough to sustain sediment transport once initiated, and how much sediment is transported by the flow in the saturated state (i.e., what is the transport capacity)? In the geomorphological and related literature, the widespread consensus has been that the initiation, cessation, and capacity of fluvial transport, and the initiation of aeolian transport, are controlled by fluid entrainment of bed sediment caused by flow forces overcoming local resisting forces, whereas aeolian transport cessation and capacity are controlled by impact entrainment caused by the impacts of transported particles with the bed. Here the physics of sediment transport initiation, cessation, and capacity is reviewed with emphasis on recent consensus‐challenging developments in sediment transport experiments, two‐phase flow modeling, and the incorporation of granular physics' concepts. Highlighted are the similarities between dense granular flows and sediment transport, such as a superslow granular motion known as creeping (which occurs for arbitrarily weak driving flows) and system‐spanning force networks that resist bed sediment entrainment; the roles of the magnitude and duration of turbulent fluctuation events in fluid entrainment; the traditionally overlooked role of particle‐bed impacts in triggering entrainment events in fluvial transport; and the common physical underpinning of transport thresholds across aeolian and fluvial environments. This sheds a new light on the well‐known Shields diagram, where measurements of fluid entrainment thresholds could actually correspond to entrainment‐independent cessation thresholds.