Tony Thomas on the Origin of Sediment Modeling and Insights from >55 Years of Sediment Studies

RSM River Mechanics Podcast

I’ve heard people call Tony the godfather of Sediment Transport Modeling and - as you’ll hear in our conversation - he very well may be the first person to use a computer to answer an engineering scale sediment question.
But most people about my age and older, know Tony for developing the first generalized sediment model. He was part of the original team here at the Hydrologic Engineering Center (HEC) where he developed HEC6, a 1D sediment transport model that was industry standard for decades.
Now, if you get a couple of model developers together, we could talk all day about transport equations and algorithms.
And we did.
But I am going to turn most of that technical modeling content, into videos to run on the YouTube page and in the RAS manual.
This conversation focuses on Tony’s insights that I think have the broadest application.
Because one of the things that make’s Tony’s career so interesting, transcends modeling.
After Tony worked at HEC, he moved to the Corp’s lab in Mississippi and then started Mobile Boundary Hydraulics, which was the premier 1D sediment modeling shop for decades.
But if you follow the timeline, that means that Tony (who only recently, actually, retired) has been predicting river processes for more than 60 years.
He is one of the few people who has seen the end of his 50 year project life predictions.
And all numerical modeling is – fundamentally - is exposing your mental models, to quantitative feedback and observational falsification.
It’s a learning loop with Rivers…
…and no one has been working that learning loop longer than Tony.
I essentially sit in that seat Tony invited as the sediment modeling specialist here at HEC. But Tony actually had a more direct influence on me than that.
About 20 years ago, when we decided to put 1D sediment transport into HEC-RAS, we got a grant to bring Tony back to HEC and he spent 5 months essentially teaching me how to develop a generalized sediment model.
There was a point in my life, where almost everything I knew about sediment came from Tony, and his insights and categories still frame the way I look at rivers.
When I first imagined this podcast, it included a conversation with Tony, reproducing some of those formative conversations we had over the years.
So in this conversation we talk about the sediment modeling origin story and some of the modeling principals he’s famous for but we also just talk about the river processes and projects that built his intuition and/or surprised him over the years.
(Photo Credit: Tony on the Arroyo Pasajero – provided by Dr. Ron Copeland)
This 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:
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/stanfordgibson
If 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