Dr Alain Recking has quantified gravel bed transport with just about all the tools available to our discipline.In addition to substantial field work- Dr. Recking has done some important and influential flume experiments.We have talked and will talk about hiding and armoring quite a bit in this podcast, because they are difficult ideas, that are hard to measure and simulate,  and critical to gravel bed processes.But Dr. Recking’s contributions to this vertical sorting conversation destabilizes armoring theory a bit…kind of literally,He found that in high gradient channels,  at equilibrium flows, vertical sorting doesn’t necessarily reach an equilibrium, but can be episodic, which is important because it leads to the pulsed transport processes.And the story he tells about how he discovered this...is just kind of narrative science at its very best.The other characteristic of Alain’s work that I think is remarkable is his a knack for pulling together immense data sets (often including substantial data from the American West) in order to pose important quantitative questions on the meta-analyses scale. And so we talked about how this lead to his gravel-bed flow-resistance  work and – what I consider – the most important sediment transport equation,  since the Parker/Wilcock-Crowe generation of innovation. We also talk about Bedload Web, where he has collected many of the measurements he used to to these analyses: https://en.bedloadweb.com/Dr. Recking works for INRAE – The French National Research Institute of Agriculture, Food, and Environment a research consortium  focused on sustainable development in those arenas. This week, on the RSM River Mechanics podcast,  we talk high gradient sorting, quantitative meta-analyses with Alain Recking.We also posted videos clips with his experiments here:  https://youtu.be/jKFlMAkD7qoThis series was funded by the Regional Sediment Management (RSM) program.Stanford Gibson (HEC Sediment Specialist) hosts.Mike Loretto edited the episode and wrote and performed the music.Video shorts and other bonus content are available at the podcast website (which was temporarily down but is back up now):https://www.hec.usace.army.mil/confluence/rasdocs/rastraining/latest/the-rsm-river-mechanics-podcast...but most of the supplementary videos are available on the HEC Sediment YouTube channel:https://www.youtube.com/user/stanfordgibsonIf you have guest recommendations or feedback you can reach out to me on LinkedIn or ResearchGate or fill out this recommendation and feedback form: https://forms.gle/wWJLVSEYe7S8Cd248