The RSM River Mechanics Podcast

Season 4

Episode here

Dr. Pierre Julien's taught and conducted research at Colorado State University for 40 years, where he wrote multiple classic texts in river mechanics including one of Erosion and Sedimentation and River Mechanics guided at least 120 masters students and 44 PhDs from 16 different countries.  He won the ASCE Einstein award in 2004, the Hunter Rouse award in 2015 and was also named a Distinguished Member in 2022.  

He is well known for theoretical advancements in fluid mechanics, sediment transport, bedform dynamics, and mud flow physics.  But Dr. Julien also has a knack for isolating memorable mental approximations that help practitioners simplify problems and form hypotheses without their models or computers.

Research Website
Teaching Websites: Erosion and Sedimentation, River Mechanics

Episode here

Dr. Ellen Wohl is a Fluvial Geomorphologist at Colorado State’s Warner College of Natural Resources. As we will discuss, she has explored and studied rivers on 6 continents (so far) but has also focused on river processes in the Colorado front range for more than 20 years, turning up important insights from both these scales.  In addition to many, many, peer review papers Dr. Wohl has also published more than a dozen books.

While we did not get close to covering all of her work, we managed to talk about a 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.  

Episode here

Dr. Amy East just finished her term as the Editor and Chief of the American Geophysical Union's (AGU) Journal of Earth Surface Processes, which is just the latest instalment in a career that includes more than 10 years editing top journals.

We will have a full episode on Dr. East's science later in season 4.  But we talked about some best practices and common failure modes in the peer-review gauntlet, which I thought made a really useful stand-alone episode.  So we ran it as its own bonus episode.

Season 3

Episode here

Dr. Peter Wilcock's gravel bed river experiments and observations have been foundational to many of the mixed-grain-class sediment transport and river mechanics developments over the last few decades.

We talk about a wide swath of this paradigm shifting work, as well as the Wilcock and Crowe sediment transport function.  We also talk about some of Peter's more recent work on restoration channel design.

Episode here

Dr. Mary Power is a food web ecologist at UC Berkeley where she has compiled careful, long-term data sets in the Angelo Reserve in Northern CA.  Her multi-decadal data sets on the Eel River, have contributed to the broader field of food-web ecology (recognized with a National Academy of Sciences induction in 2012) but have also yielded remarkable findings about how food webs function in gravel bed rivers.

Dr. Power has also uncovered multiple eco-geomorphic stories  of interactions between river mechanics processes and aquatic communities in a wide variety of clear-water rivers.  We talked about some of those findings, as well as a wide range of river ecology models that help us think about how some of river mechanics processes we talk about in this podcast, interact with the communities these systems support.

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/2425975
Resource Enhancement: Armored Catfish, Algae, and Sediment https://www.jstor.org/stable/1937361
   ...and here is the picture of the catfish from that paper

Episode 3:8 Alain Recking on Sediment Sorting, Transport, and Relative Roughness in Mountain Rivers

Episode here

Dr. Alain Recking works at at INRAE (the French National Research Institute of Agriculture, Food, and Environment) where he has studied mountain rivers in the field (western Alps), flume, and through meta-analyses of impressive data sets.

We talked about grain sorting in mountain rivers and his flume experiments that demonstrate cycles of armor formation and deformation during constant flows.  We also talked about the importance of relative roughness in high gradient rivers and gravel bed sediment transport function that he developed that corrects for overestimation in earlier equations. 

Bedload Web: https://en.bedloadweb.com

Episode here

We gathered four sediment transport model developers at the SEDHYD conference for a conversation on the guiding principles of sediment modeling we've learned over the years.  The panel includes (left to right in the picture) Blair Greimann (formerly from the US Bureau of Reclamation's Technical Service Center, now with Stantec), Gary Brown (from the USACE Coastal Hydraulic Lab), Alex Sanchez (from the Hydrologic Engineering Center) and Stanford Gibson (also from HEC) who develop ADH-2D, SRH-1D, HEC-RAS-2D, and HEC-RAS-1D.

We discussed pre-modeling practices we all share, calibration, common modeling failure modes and best practices, and thoughts on alternative evaluation.  I wish something like this existed when I was starting out but I'm glad it does now.

Episode here

Tony Thomas was the first person to apply a computer to an engineering scale sediment problem in the Corps of Engineers (and, possibly in human history).  He became broadly known as the author of HEC6 and 6T, which was the industry-standard, generalized, sediment transport model for decades.  We often call him the godfather of sediment transport modeling in our agency, and he was recognized more widely as one of the first five Einstein award winners.

We talked to him about those initial days of sediment modeling, some of the most sensitive sediment processes he identified over a 50+ modeling career, and some of the things he learned from decades of exploring rivers quantitatively. 

 
ASCE Manual of Practice 54 Reprint

Episode 3:5 Jim Selegean and the Classic Paper Draft 

Episode here

Dr Jim Selegean is the sediment transport Subject Matter Expert and Regional Technical Specialist at the US Army Corps of Engineer's Detroit District and a professor at Wayne State.  He studies sediment loads into and coastal littoral processes on the Great Lakes...in just about every way they can be studied, running an outstanding laboratory on the Detroit River.  He has also mentored a generation of hydraulic and sediment specialists that not only make the Detroit District a strong hydraulic and sediment shop, but populate several important river mechanics positions around our agency.

I also don't know anyone in my agency with quite the grasp of the classic hydraulic and river mechanics literature as Jim.  So Jim and I collaborated on something of a literature primmer episode, but in a competitive draft format.  Welcome to the RSM River Mechanics, Classic Paper Draft.

Foundations of Ecology Text
Einstein Step Length Video
 

Episode 3:4 Astrid Blom on Incision on the Rhine, Gravel-Sand Transitions, and Vertical Bedform Sorting

Episode here

Dr Astrid Blom is a professor at the Delft University of Technology where she teaches River Mechanics and River Processes.  Most of Dr. Blom's recent work focuses on actionable, river and reach scale modeling... of the Dutch portion of the Rhine to evaluate long term impacts of human interventions and climate change.  But her literature also includes investigations of river processes, novel navigation technology, and laboratory scale sediment sorting.

In this episode, we talked to Dr. Blom about her work on each of those scales.

Episode 3:3 Marcelo Garcia (Part 2) on Sedimentation Hazards, the Bulle Effect, and Transport Paradigms

Episode here

Videos below include an excerpt from the podcast with footage from the Iruya debris flows and the first talk in Dr. Garcia's Sedimentation Hazard class.
 
Full Sedimentation Hazard Class Playlist here

 The ASCE Manual of Practice is here: https://ascelibrary.org/doi/10.1061/40856%28200%2994

Episode 3:1 David Montgomery on High Gradient River Mechanics and Sediment Impacts on Human History

Episode here

Dr. David Montgomery is a geomorphologist at the University of Washington, in the department of Earth and Space Sciences (and a 2008 McArthur Fellow) where he has published several neo-classic works on high-gradient river morphology and transport.  But he has also written six popular narrative non-fiction books in the intersection between soil/sediment science and human history/policy, books like Dirt, The Hidden Half of Nature, and What Your Food Ate.   

We somehow talked about most of these things, classification, sediment transport, and wood impacts on high-gradient rivers, and sediment impacts on civilizations throughout human history.

Season 3 Preview

Episode here

Season three will be a full ~10 episode season.  This 15 minute preview introduces most of the guests, with some excerpts from the episodes.

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Jennifer Bountry leads the Sedimentation and River Hydraulics Branch of the US Bureau of Reclamation's Technical Service Center in Denver, CO where she helped to coordinate and draft an interagency guidance document on scaling sediment transport analyses to the project risk.  It is a helpful and important document that I recommend to any group moving towards a dam removal, to help them triage the analyses required for their decommissioning. 

Jennifer was also involved in the analyses for the largest anthropogenic dam removal to date, and talked to us about her team's experiences with the Elwha dams.  We wanted to wrap up our reservoir sediment mini-season talking about the final stage in the reservoir sediment life-cycle, and her experiences on the project and national scale made Jennifer an excellent guide into this world.

Episode 2:3 Paul Boyd and John Shelley on Reservoir Sediment Management in the United States

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Dr. Paul Boyd and Dr. John Shelley are involved in more reservoir sediment management initiative in the United States than anyone I know.  Dr. Boyd and Dr. Shelley are the regional technical specialists for sediment transport on the Missouri River watershed (Paul in the Omaha District and John in Kansas City)  and the Corps' national subject matter experts on reservoir sediment management.

I wanted to dedicate an episode to check in on these practices in my country, and talk about the "nascent" (as Dr. Morris described it) but growing momentum behind sediment sustainability in the United States.

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Dr. Greg Morris wrote the first text on reservoir sediment management, which generated the categories and set the parameters for a lot of the work and conversations surrounding the topic in the last three decades.  Most of us who work in this field got our start with his Reservoir Sedimentation Handbook. 

But he has also likely worked on more reservoirs with sedimentation issues - in more settings - than anyone else and has an uncommon reservoir of practical - on the ground - wisdom to offer.  We got into the details, pros and cons, and case studies of the different reservoir management alternatives from his experiences around the world.

Episode 2:1 George Annandale on Reservoir Sediment Management Motivation and Methods

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Dr. George Annandale has been advocating for our future global water supply for decades...which is more connected to sedimentation processes than you might imagine.  In his book, Quenching the Thirst  he makes the case that reservoir sedimentation is one of the major challenges to water supply resilience worldwide and managing sediment at new and existing projects is a critical component of sustainable development.

Dr. Annandale has worked on multiple projects at various scales, both as a consultant and for the World Bank.   We talked about how reservoir sediment processes impact global water supply, the economics behind these trends, and the options available to mitigate these impacts.    He also describes some of the work he has done on the Mekong River, including the innovative design of Sambor Dam. 

Season 2 Trailer

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We are releasing a second season this summer, a 4-episode mini-season or reservoir sediment processes and management.

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We are wrapping up season 1 with the second half of our first interview.  This is the rest of my conversation with US Army Corps of Engineers River Mechanics and River Engineering Subject-Matter Expert, Dr. David Biedenharn.

David Biedenharn is a senior subject-matter expert in River Engineering and River Processes for the US Army Corps of Engineers and a professor (and one of the founders) of the Tulane River Engineering Program

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Paper

The regressive erosion on the Rio Coca (Ecuador) may be the morphological event of our generation.  But, because it happened in February 2020, when there was not much room in the news cycle, most people haven't heard about it...even in the fluvial geomorph community.  In this episode we try to rectify that. 

I talked to Pablo Espinoza Giron and Pedro David Barrera Crespo, two of the scientists/engineers who have been working on the Ecuadorian response since the beginning.

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Dr. Richard Iverson led the mud and debris flow investigations at the USGS Cascade Volcano Observatory for years, including large scale flume and numerical work that unlocked a remarkable number of new insights about these high-concentration flows.   His  findings have influenced the way I  think about these events more than any other source.

With the rising interest in post-wildfire debris flow hazards, these events are getting more attention, and these findings have never been more salient.  We talked about a wide range of debris flow processes and physics including some remarkable, counter-intuitive, processes that are likely to change the way you think about these events.

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Dr. Katie Brutsche led the Regional Sediment Management Program for several years.  Regional Sediment Management is the "RSM" in the title of this podcast, and the reason this project exists.  RSM is the aspirational conceptual model of the Corps of Engineer's sediment management over the last couple decades.  We talk about the principles of RSM, the RSM process, some example projects, sediment budgets, and some surprising stats that you probably don't know about dredging.

Before Dr. Brutsche led the program she was a distinguished researcher and practitioner in coastal sediment management.  So in this episode, we increase the scale, and move downstream a bit to talk to Katie about that whole world of "post-river" sediment.

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I recently described Chris Nygaard as the Corps’ BSPS, our "Big Sediment Pulse Specialist."  He led sediment analysis and modeling on the Corps’ latest evaluation of Mount Saint Helens, downstream-sediment impacts and a dam removal alternative on the Snake River.  In those projects he analyzed the fate of sediment pulses (real or hypothetical) on the order of hundreds-of-millions of tons.  But Chris also recently spent a couple years as a project engineer with Bonneville Power, where he got to see more small, medium, and large scale, river restoration projects in a couple years than most people see in a career.  We talk about both of those project scales in this episode.

Bonus Short: SEDHYD
Dr. Tim Randle and Dr. Paul Boyd

SEDHYD Website:
https://www.sedhyd.org
Episode: here

Episode 5: John Remus on "the Big Muddy" and "the Sediment Avengers"

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John Remus leads a team of Corps of Engineers, sediment and river engineering, subject-matter experts.  This team (which I like to call "the Sediment Avengers") deploys to the Corps' most problematic sediment and morphological challenges around the country.  And that's a fitting role for the man who manages the river sometimes called the "Big Muddy."  In his "day job," John is currently the the chief of the Corps Missouri River Basin Water Management Division where he leads the team that manages the massive reservoirs on the upper Missouri.

But for most of his career John led the Sedimentation and Reservoirs branch at the Corps' Omaha district.  Over the years I made two observations about this branch: 1) it was the only Corps-District Branch with an specific sedimentation mission and 2) it generated a remarkable amount of sediment analysis and river mechanics talent...which always made a lot of sense to me, given how much I've learned from John Remus over the years.    

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Dr. Joanna Curran is probably best know for her early laboratory work as a grad student and professor on step-pool systems and the Wilcock and Crowe transport function.  But she has since worked on northwestern rivers with several engineering firms, and most recently joined the Corps of Engineers at the Seattle District.  This academic/private sector/public sector perspective and experimental/numerical/field experience gives her a couple different multi-perspective views on rivers.  When you match those perspectives with a fundamental curiosity about how sediment processes work, it makes for a fascinating conversation.  

We talked about Wilcock-Crowe, step pool systems (see her flume experiment video below), gravel clusters, "low flow bed tempering," the impact of vegetation "porosity" on sediment mechanics, and several other topics.

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Ron Copeland has worked for the Corps of Engineers for 52 years at the LA district and the Corps Coastal and Hydraulics lab in Vicksburg Mississippi. He was also a principle engineer at Mobile Boundary Hydraulics for a decade.  Dr. Copeland has not only been on a very short list of the very best 1D sediment transport modelers for decades, he has developed several equations and algorithms that multiple models use.  In 2020, he won the ASCE, Hans Albert Einstein award. 

And, while I think Dr. Copeland's modeling expertise has a lot of value to the community growing around this podcast (and we will did talk about it) his sediment and river mechanics contributions include much more than modeling.  He was responsible for Corps early guidance on restoration channel design and developed an important, expedited tool to evaluate sediment continuity of restored channels, a common failure mode of early restoration projects.  We talked to him about all of that...and some more technical topics that we spun out into video shorts (see links below).

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Molly Wood is the National Sediment Specialist for the USGS Water Resources Mission Area’s Observing Systems Division. She develops policies and methods for measuring fluvial sediment transport and for computing streamflow using complex rating techniques. She also teaches national and international training courses on surface-water and sediment data collection.

I have lost track of just how much of what I understand about sediment data I've learned from Molly.  But a substantial percentage of what I know about sediment measurements, sediment data processing, and potential data pitfalls comes either from her publications or conversations we've had over the years.   This was a fun conversation that hit on several of those topics.

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Dr. David Biedenharn is a river mechanics, subject matter expert, with the Corps of Engineer's Coastal and Hydraulic Laboratory.  He is a professional engineer with over forty years of experience in hydraulics, river engineering, sedimentation, channel restoration, and fluvial geomorphology.  Dr. Biedenharn also teaches in the Tulane Department of Science and Engineering, where he helped develop their River Science and Engineering Program. 

But the main reason we invited David to be the first guest on the podcast, is that he is responsible for mentoring a generation (and, by now, more than one generation) of River Scientists and Engineers in the Corps of Engineers.    From the first time I met him in my early 20's, conversations with David have formed the way I think about river processes and our engineering interventions in river systems at every scale.

Trailer: here

Host: Stanford Gibson is the sediment specialist at the Hydrologic Engineering Center (HEC) and a national, sediment transport, subject-matter expert for the US Army Corps of Engineers.   He is in charge of the sediment transport capabilities in HEC-RAS, a popular river modeling software.  He never really figured out when to stop going to school and ended up with a PhD (UC Davis) in engineering and three masters degrees (Restoration Ecology, Geotechnical Engineering, and Theology).   He has built mobile-bed, sediment transport models of some of the world’s largest rivers including the Mississippi, Madeira, Missouri, and Mekong - and models of a couple dozen smaller systems (and even some that don't begin with "M").  Stanford has taught hydraulic and sediment transport modeling in more than 15 countries and is interested in emerging mediums of technology transfer....like web videos and podcasts.    CV

For more sediment process, analysis, and modeling content, check out the HEC sediment YouTube Channel:
https://www.youtube.com/user/stanfordgibson  

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Then new episodes will show up in your podcast feed as they are released.
But check back here for bonus videos and cited content.

We will release episodes every two weeks, on Friday, until February.

This project received funding from:

The Regional Sediment Management R&D Program
The Flood and Coastal Storm Damage Reduction R&D Program
The Hydrology, Hydraulics and Coastal Science and Engineering Technology Program
The Post Wildfire Flood Risk Management R&D Program