Pierre Julien on Bed Forms, High Concentration Flow, and Engineering Rules of Thumb
Dr. Pierre Julien joined the Colorado State faculty almost 40 years ago, where he worked at CSU’s Engineering Research Center and Hydraulics laboratory. His book, Erosion and Sedimentation, is one of my most common references, and several of the algorithms we have in HEC-RAS (particularly for mud and debris flows) come directly from this text. But while Dr. Julien’s textbook includes as many partial differential equations and tensors as any other hydraulics text – maybe more – it also includes “rules of thumb” scattered throughout. I have integrated several of these nuggets of actionable, river mechanics wisdom into my field toolbox. They are heuristics I use regularly to quickly triage river processes and engineering proposals while standing next to a river or sitting in a meeting. So I was curious if these rules of thumb would make an appearance in our conversation…and I was not disappointed. We do talk some theory. He shared a couple great metaphors that helped me visualize some of the complex theoretical principles of fluid mechanics better than I had going into the conversation. But Dr. Julien does, also, intentionally develop these decision heuristics and rules of thumb, to help practitioners quickly rule in or rule out alternatives and they popped up throughout our conversation. Dr Julien won the Einstein award in 2004 and the Hunter Rouse award in 2015 the American Society of Civil Engineers lifetime achievement awards for sediment and hydraulics respectively (which is apt as we ended up talking about both the men those awards were named after). He was also named a Distinguished Member of the American Society of Civil Engineers - their highest honor - in 2022. Dr. Julien has completed projects world-wide with 50 different agencies including world bank and UNESCO and has guided at least 120 masters students and 44 PhDs from 16 different countries.This series was funded by the Regional Sediment Management (RSM) program.Mike Loretto edited the first three seasons and created the theme music.Tessa Hall is editing most of Season 4.Stanford Gibson (HEC Sediment Specialist) hosts.Video shorts and other bonus content are available at the podcast website: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
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1:03:08
Ellen Wohl on World Rivers, River Restoration, and the Dimensions of Fluvial Connectivity
We’re kicking this season off with one of the most prolific researchers in River Science. Dr. Ellen Wohl is a Fluvial Geomorphologist at Colorado State’s Warner College of Natural Resources.As we will discuss, Dr. Wohl has explored and studied rivers on 6 continents (so far). But she has also focused on river processes in the Colorado front range for more than 20 years, Turning up some important insights from both these scales. I’m not sure if Dr. Wohl leads the fluvial research community in annual words published…But she has to be in the conversation. In addition to countless peer-review papers she is also prolific in short-form and long-form science communication, publishing frequent blog posts and more than a dozen books.We managed to talk about a pretty wide range of topics, including large river processes, the flood pulse model, the history and current state of restoration research and practice, and a big idea we haven’t interacted with much on this podcast yet: fluvial connectivity. I first connected with her work through the multi-author review papers she led on the state of river restoration science and practice. These papers came out twenty years apart, and the second one came out twenty years ago, so I was interested to check in on the state of restoration research and what we’ve learned about this no-longer novel field.But because of her body of work, an interview with Ellen can only touch on a small fraction of her work. Since I was asking the questions, our conversations mainly followed my interests, and some of her most cited work. But this link provides a gateway to a broader range of her work:https://sites.warnercnr.colostate.edu/ellenwohl/This series was funded by the Regional Sediment Management (RSM) program.Mike Loretto edited the first three seasons and created the theme music.Tessa Hall is editing most of Season 4.Stanford Gibson (HEC Sediment Specialist) hosts.Video shorts and other bonus content are available at the podcast website: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
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1:02:51
"Ask an Editor" with Amy East (Bonus short)
The peer review process can feel like hazing to a new (or not-so-new) river scientist. Many excellent practitioners are learning from their rivers every day, but it can feel like if it doesn't get into peer review, it doesn't "count." So we separated this short segment from my conversation with Dr. Amy East, the Editor-in-Chief of AGU's Journal of Geophysical Research: Earth Surface (and >10 years experience editing high impact journals) to provide a little primmer on how to negotiate the peer review process. Amy has some really helpful thoughts on how to move from a "Report on a River" to a "Scientific Contribution" that will land well in a journal....and look for the first episode of Season 4 in a few weeks.This series was funded by the Regional Sediment Management (RSM) program.Mike Loretto edited the first three seasons and created the theme music.Tessa Hall is editing most of Season 4.Stanford Gibson (HEC Sediment Specialist) hosts.Video shorts and other bonus content are available at the podcast website: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
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18:15
Peter Wilcock on Gravel Bed Rivers, Partial Transport, Armor Layer Persistence and Channel Design (Plus Wilcock & Crowe)
When HEC hired me to add sediment transport to HEC-RAS almost 20 years ago now, I inherited a set of sediment transport functions that were mostly developed in the early to mid 20th century. These were – and continue to be – important equations.But when I sat down with the RAS team To talk about the new science I was excited to include in a river mechanics model.I pulled out the same binder I brought to this interview We are wrapping up our third season of the podcast, and our three-part mini series on gravel bed rivers And talking to the scientist who wrote all the papers in that binder, seems like a fitting way to wrap up both.Dr. Peter Wilcock spent much of his career at Johns’ Hopkins, where he and his team developed the Wilcock and Crowe transport equation and did some of the most important gravel bed transport work that was hitting the journals when I was coming of age in the field.Peter is unquestionably one of the most important contemporary contributors to quantitative gravel-bed transport science and engineering.He won the American Society of Civil Engineers Hans Albert Einstein award in 2008 and is a fellow of the American Geophysical Union.And we talked a lot about that fundamental, early work, that is just kind of part of established gravel bed transport theory these days.But 10 years ago he moved to Utah State, improving his proximity to classic gravel bed rivers, and in the years since I put that binder together of his paradigm shifting work, Peter has been very intentional about translating his science into practical channel design methods, particularly for restoration channel designs.So we talked about both…starting out with more of the channel design topics and then moving into his classic findings. The Link to Peter's Stream Assessment and Design Class Materials (including iSURF) that we talk about is here:https://qcnr.usu.edu/wats/programs/short-courses/sediment-transport/course-materials-2022We also talk about Ron Copeland's channel design method. We made a short video with Ron on that method which is good background for this episode here:https://youtu.be/ykJ3FA39p0gRon's podcast is here:https://podcasts.apple.com/us/podcast/ron-copeland-on-analytical-channel-design-the-laursen/id1650989239?i=1000587444097Finally, we also have an interview with Joanna Curran (the Crowe in Wilcock and Crowe) which makes a good companion to this episode here:https://podcasts.apple.com/us/podcast/joanna-curran-on-gravel-bed-rivers-wilcock-and-crowe/id1650989239?i=1000589529286This series was funded by the Regional Sediment Management (RSM) program.Mike Loretto edited the first three seasons and created the theme music.Tessa Hall is editing most of Season 4.Stanford Gibson (HEC Sediment Specialist) hosts.Video shorts and other bonus content are available at the podcast website: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
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1:30:53
Mary Power on River Ecology, Disturbance, and Inverted Pyramids
tDr. Power is a food web ecologist at UC Berkeley, where she leads the Power lab which has compiled careful, long term data sets in the Angelo Reserve in Northern CA.In addition to her early work, in Panama and the Ozarks - which we touch on briefly - Dr. Power’s multi-decadal data sets on the Eel River, have yielded remarkable findings about how food webs function in gravel bed rivers…and spoiler alert, it sometimes involves the sorts of things we tend to talk about here…like the gravel - and how it transports.While this is a physical science podcast, I hoped to include interviews with river Ecologists from the beginning particularly ecologists who make careful observations at that interface of physical and biological processes. And I always hoped I could kick that emphasis off with Dr. Power.I teach an Ecogeomorphology module in one of our classes here at HEC and I always lead that with the Eel river story she shares About 20 minutes into this episode.That Eel river story was one of the early influences that got me interested in the ecological interactions with river mechanics processes.I also asked Mary about a couple of Ecological models and categories, that have corollaries in geomorphology. So we talked about disturbance, alternative stable states as well as the Box model and the Ideal Free Distribution, which are just really helpful ideas for anyone who is interested in rivers.Dr. Power was inducted into the National Academy of Sciences in 2012.Links: Serengeti Rules: https://www.pbs.org/wnet/nature/serengeti-rules-dhbtnm/19906/Disturbance and Recover of Algal Assemblage on OK Stream https://www.jstor.org/stable/2425975Resource Enhancement: Armored Catfish, Algae, and Sediment https://www.jstor.org/stable/1937361Episode Photo: Eel RiverThis series was funded by the Regional Sediment Management (RSM) program.Mike Loretto edited the first three seasons and created the theme music.Tessa Hall is editing most of Season 4.Stanford Gibson (HEC Sediment Specialist) hosts.Video shorts and other bonus content are available at the podcast website: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
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