Stanford [00:00:13]:
Well, we reached the end of the first season and we're gonna end the way we begin. As promised, we're wrapping up with the second half of our conversation with our first episode guest, David Beatnharn. As we mentioned in that first episode, David is one of the senior subject matter experts on river mechanics, river engineering, and fluvial geomorphology in the Corps of Engineers. And as we talk about in this episode, he also helped launch a new river science program at Tulane University. But mostly we started and ended with David because so many mid career practitioners in my agency learn so much of what we know about how rivers work from him. And he just has such a thoughtful and generous approach to science and mentoring that the whole idea from this podcast really came from the hope that I could share some of the insights I've learned from David with others who live in this wild world of river process. And near the end of this episode, I stepped back and asked him a few kind of metascale questions about his personal and professional approach to science, insight and wisdom. You know, the personal practices, how he orients his teams and himself to a new river to give himself the best chance to see through the noise and actually observe the world clearly and carefully. Before we jump into the final episode, let me answer the main question I've been getting. Yes, there will be a second season. We have already recorded and booked some episodes straight off my wishlist, and well be talking to more professors and practitioners outside the core in the USGS next season, but I suspect it will be late 2023 or early 2024 before we start running those. It turns out I do have a day job. In the meantime, I have a Google forum on the podcast website where you can recommend guests and papers, or reach out to me on LinkedIn, Researchgate, or YouTube. And if you like this series, consider passing it along to others who do this kind of work. I'm Stanford Gibson, national sediment subject matter expert for the corps of engineers and the sediment specialist on the HSC Ras development team. And this week on the season one finale of the RSM River Mechanics podcast, the rest of my conversation with senior Corps of Engineers river mechanics specialist doctor David Beetnhardt. All right, David, I have this theory.

David [00:02:17]:
You got plenty of theories.

Stanford [00:02:20]:
I have no lack of theories. But I have this theory that if you've worked in any field as long as I have, or especially as long as you have, chances are that you did something at some point. It's a paper, a report, a project that you know was really, really good and really really helpful and really, really useful, but it was completely ignored. Like, in the back of your head. For decades, you've been thinking, you know, this was good work and it should have gotten more attention. And so one of the things I want to do kind of recurring on this podcast is maybe ask some folks, what was that thing? What was the thing that you feel like, oh, that was really cool. But just the way that journals work or institutional knowledge works, it's been mostly forgotten. So let's not forget it. I do feel like there's one project that you and I have talked about where maybe your methods were not super sexy, but you ended up with really helpful, actionable data that got used. That's Katrina. Can you tell me a little bit about what your team did after Katrina?

David [00:03:23]:
Yeah, Katrina was a really different project and world for me, and everybody knows it was the devastating hurricane for New Orleans. Well, I was here at Erdeck. This is before I retired, about a year or so before. But Steve Maynard used to work here. He went down on the initial team, and they were looking. There was a group of people, the geotechs were down there and a lot of folks. This was just a few weeks after the hurricane, and so we were just getting the city dewatered. And he called back up here to Urdec and said, man, I need some help down here. We need to figure out what's going on when these levees broke. So I went down with another group, and we met with the teams down there. And so I was thinking, what am I going to do down here as a river engineer? You know, we're talking about flooding in the city, and I'm way out of my wheelhouse. But it slowly became apparent. It dawned on me that one of the key things was just kind of doing a forensics investigation to figure out what happened. All the power was out. Nobody knew when the walls broke or when the flooding hit different areas.

Stanford [00:04:40]:
The gauges were washed down. We didn't have any data.

David [00:04:43]:
It was nothing. And so I said, well, how are we going to get that information? So I put together a team here to go down and start trying to gather that information. And we did a lot of different things. We would go down, and after about three or four weeks, people started filtering back in to pick up their belongings or the trash or just clean out their house. And it was just total devastation. And we would go down and we would go through the neighborhoods and we would interview people. We'd find people there. We'd go up and interview with them, ask them if they were there during the flood, and if they were, we would get their observations. A lot of them actually had videos and pictures, and so that was very helpful. There was one group we talked to that were firemen up in one of the high rises over on Lake Pontia. Train looking down at the 17th street canal. And there was a fire, one of the. So they were interested in the building that was on fire, but they just so happened to capture the flood wall breaking, too. They weren't interested in that. They were looking at the fire. So, you know, we got that type of information. But one of the things we found out through that project, the first time I was down there, I stayed about three weeks or so, and I found out that you couldn't stay down there that long because all you're doing is talking to people whose whole lives have been lost and destroyed. And I talked to one guy. He had lost, like, you know, four family members. And so you start to, you know, empathize, and it just becomes emotionally troubling.

Stanford [00:06:20]:
Yeah.

David [00:06:20]:
So we had to. We had to broaden our team out and start going down, you know, in groups and come back for a couple weeks and go back down. But we. We ended up interviewing maybe eight or 900 people. So, like I say, we were looking at a lot of different metrics. And Daveed Abraham, who's actually retiring right now, tomorrow. Yeah, retirement, yeah. And Daveed works here with us, and Daveed and I have worked together for a long time. Great guy. And so he was on the team. He was part of our team. And one of the things he started looking at was, okay, I'm gonna go in some of these houses and start looking at clocks. See when the clocks stopped.

Stanford [00:07:03]:
So battery operated clocks.

David [00:07:04]:
Battery operated clocks. And so we talked about that and said, oh, my gosh, that ain't gonna work. Cause I was thinking about my battery operated clocks at the house, and I hadn't changed the battery in ten years, so, you know, who knows? But he started going in, and he developed, as Daveed, only Daveed can do with a protocol to do it. And the clock had to meet certain conditions, and it had to been inundated.

Stanford [00:07:30]:
Right. The premise here is that the clock would stop when the water reached it.

David [00:07:36]:
Right, right.

Stanford [00:07:37]:
And so you could survey in the clock and actually have a time.

David [00:07:39]:
Yeah. And get the elevation of the clock, you know, whatever. So he started doing that, and as you expect, it was a lot of outlier, a lot of variability. But it's like any other type of data that you and I have been talking about. It's messy, but you can use it, and if you have to, it takes that experience to interpret the data. So we started getting that data in, and then we would take that and we would weave that in with the interviews where Mister Jones said that he was at this location, that he saw water coming in at a certain time, and then we would get another interview. So we had a map with all these points on it that showed when and what time water came in. And when I first looked at it, it didn't make any sense, because you'd have a guy that saw water at 10:00 in the morning, and then three blocks over, the guy didn't see it till noon. And then, and we would see this type of pattern till finally we put a topographic map on it. Because when you're in New Orleans, you've got this vision, everything is flatden.

Stanford [00:08:50]:
There's no topography in New Orleans, but.

David [00:08:52]:
That'S not the case. And a foot of rise or fall makes a big difference.

Stanford [00:08:57]:
Big difference.

David [00:08:57]:
In the time we brought that in, it just kind of all came together and it worked. And then the clocks were the same way. So that was what we did. And through that we were able to go back in and reconstruct when different flood walls failed, which then the modelers could come back and use that information to help their models.

Stanford [00:09:20]:
And we were the modelers. Over at HeC, Gary Bruner was doing forensic modeling, and we were always talking about how does it match the beaten heart data, Beetenhardt et al. Obviously you had a big team.

David [00:09:30]:
Oh, yeah, it's always an et al with me. I always need a lot of it's. And all's. Yeah, it was great.

Stanford [00:09:38]:
One of the reasons that's not a classic river mechanics story, but one of the things that I really find interesting about that story in the river mechanics framework is you used a word, the word you used was a forensic investigation. And I feel like whenever we get involved in a river that's kind of misbehaved from an anthropogenic point of view. It's always a mystery, it's always a forensic investigation, but we never have the data we want. But just because the data aren't on the Internet doesn't mean they aren't out there. And so one of the things I find so instructive about this study is that the data weren't out there. And so you treated it like a detective.

David [00:10:18]:
Exactly.

Stanford [00:10:19]:
Where could we get the data that we want? I do think that that has really broad application in river engineering. River mechanics in general, it's a key.

David [00:10:29]:
Part of what we do. And I look at almost every river study I do as a forensics investigation. Me too, because that's exactly what it is.

Stanford [00:10:37]:
Because you are thinking on the decadal scale, you want to know how did it get here, have some chance of knowing how is it going to go?

David [00:10:44]:
Right. And the problem is, as you said, that particularly today with younger engineers, that we all go to the Internet.

Stanford [00:10:51]:
It's not on the Internet, doesn't exist.

David [00:10:53]:
It doesn't exist. And that's just, that ain't the case. And, you know, I always tell them, go to the districts or wherever. And when you go to the district, you have to realize that, you know, in a geomorphic assessment, I'm looking for data going back as far as I can know, 100 years, 200 years, whatever I want to. In a geomorphic assessment, I want to understand how the river system got from where it was sometime in the past, maybe 50 years, 100 years or more, and what brought that to present. So I want that older data and that's probably not going to be out there on the Internet.

Stanford [00:11:27]:
Yeah.

David [00:11:27]:
Which means you're going to go to the district and you got to realize that all the people who may have known about that data are, have retired or gone on somewhere else. And so you're going to end up doing some digging and you're probably going to be in some storerooms or file rooms that warehouses, I think, about, you know, Indiana Jones, you know, arc of the covenant or whatever, but you're going to have to dig it out. But sometimes you'll find just a treasure trove of information that's out there. It's not a minor, insignificant part of any study we do to get that data. And, but it's, it's a critical part. And then you have to weave that data together. And we look at a lot of different factors and you mentioned the forensics component. That's what we're doing. You know, we may have historical survey information, we've got gauge information where we're looking at, you know, changes in the stage discharge relationship or we're looking at what, what did our field investigations tell us. And then when you start to integrate all that and you weave it together, sometimes you have all these different pieces of information and then they're all pointing in the same direction. You feel great. But then sometimes maybe the survey information is not telling you the same thing that what you saw in the field or it's disagreeing with the gauge information or the gauge information is showing you something going on differently at a low flow versus a high flow. So that means you got to figure out what's the driving processes that are affecting my high flows that are different at my low flows. So you have to weave all that together. And it's not always easy, and it's never, rarely is everything pointing in the same direction and giving you the exact same answer. But you've got to, you've got, you weight, the data. Some of it you have more confidence in than others. And that's what you ultimately end up having to do to come to some final answer. But a lot of times we don't have an answer. It's an unknown, and you're just not sure what's going on. And you have to go on from that.

Stanford [00:13:35]:
This illustrates what you're saying about it's not a cookbook, right? It's not like you go to the USGS, you download the clean data, you do, you run your equation, you have your result. I once paid an intern to review 1500 microfiche newspaper articles because I didn't have a good flood record of the event. And so I had her go and just pull these microfiche newspapers and tell me what dates had flooding to help build that record. There are ways to get information that aren't just download from the Internet, but you do have to approach it a little bit like a detective.

David [00:14:09]:
You do. And to me, that's the fun part of it. That's exciting. I agree. If it was just getting data and.

Stanford [00:14:16]:
Plotting it up, I'd do something else for living.

David [00:14:18]:
Me too.

Stanford [00:14:19]:
So if you go to most undergraduate engineering programs, maybe all of them, river engineering isn't a degree you can get in undergrad. And so how did you realize how rivers change, how they erode, how they deposit, how they migrate, that that wasn't just going to be an important part of our agency's mission, but like something you might actually want to, like commit your career to. Like. How did that happen?

David [00:14:45]:
Well, when I first went to work for the corpse in the 1970s, late, late seventies, I actually worked for the corps in 73 when I got out of the Air Force, but I was a technician to engage in discharge work.

Stanford [00:14:59]:
Cool.

David [00:14:59]:
But when I came back as an engineer in the later seventies, I was working with Brian Winkley, who was the chief of the podomology section in Vicksburg district.

Stanford [00:15:09]:
Let's pause that. I knew that was great, because this is where I heard the first time, three or four years ago, when they stood up the geomorphology and potomology program. And I realized this describes the field I work on, and it's a word I've never heard. What is potamology?

David [00:15:25]:
Podmology is the science of rivers. It's kind of a simple definition for it. And the podomology program had been around in the core since, I think, the forties or so, and it was primarily focused on the Mississippi river. And so it was a podomology program within the districts to study the river and understand how it was adjusting and responding to all the things man and nature had done to it. And the podomology program kind of had a cyclic nature of funding over the years. They had some major floods, and then a lot of money come in, so a lot of potholmology investigations would happen. And then all of a sudden you hit a dry period. So in the seventies, we had quite a bit of work with the potomology program. So that's what I started working in. But we also were doing the section 32 program in the small stream. So I had the benefit of working in the podomology program on the big river, Mississippi, but also doing the small stream stuff with the section 32 and the North Mississippi work. And when I went to work with Brian Winkley, who was an engineer, but I, he liked geologists and geomorphologists. He liked that. And so we had a geologist geomorphologist named Bob Rentschler, who worked in the branch with us then. And Bob was doing a lot of work up in North Mississippi. So for about the first year that I worked with the corps, I would spend about every other week in the field, walking creeks and floating creeks and flying the rivers with Bob Rinschler and learning about geomorphology and channel response and a lot of erosion and a lot of degradation. So that's what got me started. It was a blessing and a curse. I look back on it. A lot of the engineers that came in with me at that time were in the hydraulic section. I was in the podomology section. And so they developed their skill sets at computers and were able to run computers, models, and do a lot of work with that. You know, I never had a computer, hardly the first year or two I was there, but I learned a lot about the field application and looking at things. And plus Winkley, Brian Winkley had a lot of contacts with some of the academic experts around the country and the world, Darrell Simons, Stan Schum from Colorado state. We would interact with them a lot. So I was, you know, just sitting around listening to these, these great guys you know, and what they were saying and just, it just really interested me. And I said, well, this is what I want to do. And so that's how I got involved with it.

Stanford [00:18:11]:
So speaking of pathology, you and Barb Kleiss have started an engineering certificate. Tulane. You know, I started this with a little gambit that you can't get a degree in river engineering, but you and Barb have changed that. You've set up a certificate program in river science at Tulane. And, okay, so from the outside it looks to me like your objective is to help emerging water resources professionals kind of think about rivers as these dynamic geological and biological systems so that when we try to manage rivers, we're thinking of them as these dynamic geological and biological systems, not just as like a really big ditch. I don't know how I did, but what was your actual motivation for starting that program?

David [00:18:51]:
Barclays, who at that time was working for the corps, she's retired since, but she and I were friends and we were talking and she's a water chemistry biologist, wetlands person, but she was the head of the science and technology program at Mississippi Valley Division office. But we had been talking for a number of years about podomology program and whatever. And so she was instrumental in getting the geomorphology and pathology program started at MVD.

Stanford [00:19:20]:
That's right.

David [00:19:21]:
But as part of that we were thinking about how can we reach out, particularly to corps of engineers and scientists or planners or whoever and inform them about Potomac river engineering, river sciences? And so we were looking around trying to think, how could we, you know, we could, we could do, you know, workshops and teach lectures and do lectures and such. But we thought it'd be good if we could actually, you know, interact with a university so we could get college credits for this. So at that time, Tulane was trying to bring back their engineering school. So we were talking with Doctor Meade Allison at Tulane and we went down and started talking to the department heads down there and they said, yeah, we'd like to work with you. So they brought back the engineering, river engineering and science program and we became part of it. But the idea was, let's teach this not purely from an engineering perspective, but also bring in the geology, the ecology and the broader view, kind of epidemiology, vision. And so actually these classes are taught. We co teach all of them. Most all of them. The first introductory class, I teach in it. Barb teaches me, Allison Ehab Moseley and Jack Kilgore. We all teach in it. So we all had different modules. We're throwing a lot of different things at them. It's not just one. And then we have classes in environmental restoration, and so we're teaching restoration, but it's not just me telling them about river engineering and sediment transport. We have Jack and Barb and Amanda coming in with their view from a whole different discipline. So it's kind of a challenge for us and a burden. It puts a lot of work because we have to be involved in a.

Stanford [00:21:19]:
Lot of each other's world.

David [00:21:21]:
We all work well together, but it is a challenge, but it's important, I think, that we get the students thinking about, it's not just engineering, and we have to think about these other sciences as well. And we have other classes, river mechanics, that I teach, but it's not the river mechanics class I took at Colorado State. I don't get into the equations and the computational intense.

Stanford [00:21:46]:
They're not going to drive Einstein or Maya Pierre Mueller or anything like that.

David [00:21:49]:
No, because that would mean I'd have to go back and remember how to do Einstein. But, you know, it's taught at a broader level. So we've had planners, we've even had lawyers take the class. So it's a certificate program. I think we have about five or six classes now. Six classes I think that you can take and you get this river engineering certificate, but they're also, you're getting college credit and you can, you know, apply that toward a master's or a PhD. We're working on getting those accredited at Tulane. But if you, you know, you could go somewhere else, you can still usually transfer, you know, a number of hours. So that was the idea. And we teach it through Zoom as a hybrid type of class. And this has been a challenge for me, you know, as an old guy trying to do online teaching. We've really put a lot of effort into trying to do the zoom hybrid teaching properly, and it takes a lot of work to do online properly. And we have students from the core. We've had them from many of the districts from out west, back east and everywhere. And I can say we've had engineers, planners, biologists, lawyers. And so the whole concept is to just get some general, practical river engineering and science lectures out there so people can get an understanding of how complex these systems are.

Stanford [00:23:15]:
You know, it's just occurring to me right now that this is actually an extension of your original, like, kind of regional rivers or systems vision. Is that like early on, kind of when I first came under your influence, you were really helping us to understand that you need to take the watershed view, you can't just look at the project scale because it is connected and interacted with what's upstream and what's downstream, what's in the watershed, the sources, the pathways and the sinks. And this is just kind of adding another dimension. Even if you do think about all that, you can't just think about the morphology or how the river responds kind of mechanistically. You have to be thinking about how is that interacting with the ecology, the river chemistry? You moved from this, like, interconnected spatial scale into an interconnected multidisciplinary scale.

David [00:24:02]:
Absolutely. And I learn a lot. I sit through their lectures and they sit through mine, and we help each other. And so each of these classes usually gonna have two or three of the professors in there. And so I think that's a plus as well. But I've learned a lot, you know, and I learned a lot working with the different disciplines that made me think about things differently. An example is on the Mississippi river. You know, Barb had done a lot of work in wetlands and floodplain work up on the Cache river and stuff. But she's looking. She was looking at different processes, but she was, you know, she and I would talk and it got me thinking about the floodplain. And then, you know, what's going on in the floodplain. How is that floodplain morphology? How is that affecting the channel and the flood flows? And you work with people with different backgrounds and disciplines. Sometimes they get you thinking about things differently. So now we're really starting to look harder at the Mississippi river floodplain and how that floodplain and the vegetation and the changes. Yeah, but how does that affect flood flows? Yeah, you know, it used to be we stick a roughness in there for the overbank.

Stanford [00:25:14]:
That was it, 0.06.

David [00:25:15]:
There it is. It was 0.707.

Stanford [00:25:19]:
Okay. Yeah, well, yeah. Kudzu.

David [00:25:20]:
Yeah, but, you know, but now we're starting to look at. And we have models, we have ADH models that we can really get precise information there. And we're. We're able to assess some of the impacts, what happens at a flood flow, you know, if the vegetation is grown up or if we clear cut it or something. And that's something, you know, we often think it's all the channel, you know, what's the filling in the channel. But when those, when the river goes into the floodplain, the Mississippi river has a big floodplain, even though we've levied it off the average width of the floodplain, say, from Baton Rouge to Cairo is like six or 7 miles. Six or 7 miles is a lot of area. And so you think about everything that's going on in that floodplain has a big impact. But I'm saying is, this interdisciplinary approach seems to help me. I'm a guy that needs a lot of help. Sometimes it gets me thinking about things a little differently.

Stanford [00:26:20]:
So I went back for this master's degree in ecology at UC Davis, and I thought that I was going to become an ecologist so I could be a geomorphologist, this hybrid person. I didn't. It didn't make me an ecologist. It did help me benefit from the ecologists there in the room, though. And the other thing it did is it just made me think about my discipline better, because ecology is used to dealing with messy data and sediment transport. Geomorphology, our data are more like ecological data than hydraulic data because they're a mess, and ecologists are used to thinking about that. So I actually found that interacting with ecologists didn't just kind of make me open to those ideas, but actually imported analysis tools into my field as well.

David [00:27:09]:
Oh, yeah, that is a big help. And messy data is a key to what we do. Stanford, as you know.

Stanford [00:27:16]:
Well, that's a good segue. Obviously, you've thought a lot about, if you've stood up a program, you've thought about how to leave behind some of the big ideas that we need to be thinking about. And so what are some of the big ideas that you would want to impart if you had a chance to introduce maybe a hydrologist or a hydraulic engineer in our organization that doesn't have a lot of river mechanics or geomorphology background. If you were to introduce them to a couple of big ideas or say, or give them some homework in the next few years, start to think about these ideas. What are some of the big ideas that you try to pass on to younger career folks like myself?

David [00:27:57]:
Your younger career?

Stanford [00:27:59]:
Maybe even younger, yes. Forget how long I've been around.

David [00:28:03]:
I know. Well, I go back to what I call the first law of river engineering, and I'm not sure who coined this. First time I heard it, I think it was Charlie Elliott. He used to be river engineer I worked for, for a long time. Really great guy. But the first law of river engineering is that complex river engineering problems often have simple, easy to understand, but wrong answers.

Stanford [00:28:30]:
Let me reproduce that. Complex river engineering problems often have simple, easy to understand, wrong answers. They're simple, and they're easy to understand they also happen to be false.

David [00:28:46]:
And I run into that all the time, you know, and there's, people have their, all you have to do is follow my cookbook or all we need to do is ABC. And I, that's usually wrong. Rivers are usually mother nature, you know, usually has a bigger dredge than we do sometimes. And, but that, that's a key thing is just this, this caution that it is just like all we've been talking about is, you know, we go to school, we come out with it, we're hard charged and we're ready to apply the equations. Well, apply them with caution. Everything is with caution. And that I think about just the natural huge variability in streams and how dynamic they are and the complex response mechanisms, the feedback mechanisms and the, and sometimes I think we don't think long term enough. We're, as humans, we're short term critters. We think two, three years is a long time. But in a lot of streams, you know, two to three years is nothing. I can think of a lot of cases where I've seen projects. An example is one, a stream bank civilization project, and it was on a meander bin up near Grenada, Mississippi. And it had been stable and it worked well, probably from the, I think it went in, in the late seventies and it worked well for like 20 or almost 30 years. And then all of a sudden it failed catastrophically. We had like a 300 foot hole developed in the structure. Well, what happened? Something changed or it could have been just a long term creep in. Local tow scour is what it was. But, you know, we put structures in and they work for two or three years. We think they're great and we walk away. But we need to think about how streams respond in the long term. Let's look at it. Ten years, 20 years, that's what I'm interested in. And oftentimes we don't have time for that. But if we can monitor them for longer time, that would be better. I guess it's caution, caution, caution. And be careful whenever we're teaching. Sometimes I say, what are the goals for this class? And I'll say, well, it's to bring all the students up to the level of confusion that I have because the longer you work with rivers, to me, almost the less confidence you get, you know, and I see a lot of people that have extreme confidence for no apparent reason. And then here I am. I've been working for 40 something years and, you know, I've lost all confidence because rivers are so dynamic. And, you know, I've been proven wrong so many times. You know, I think something's going on. And every time I look at a river system, I learned something new, but it always adds to my caution. And I think about when we start doing stream modeling, for instance, you know, we can do, we have the models and they're very precise. We can get absolute precision.

Stanford [00:31:58]:
Oh, I can give, I can give you an answer to eight decimal point places.

David [00:32:01]:
I love eight decimal places. Right. We do that all the time. But that's absolute precision. But the, the data that that model is based on is data that we take from the river. Surveys gauge data, and that's just a snapshot in time. It's just a sample of the bigger river population. So it's not capturing the entire variability and dynamics of the big river. And I kind of equate that to you're going to cut a board for you to build a cabinet. And so you measure that, the length of that board, and you measure it very, very precisely with a micrometer. That's like our models. Then we mark that board with a piece of chalk and that piece of chalk is like the data set that we get for the river. And then we take a hammer and we smash the board with a sledgehammer and that's the river. And so that's kind of the way I see it. And so we always have to be, you know, aware that, that even we're getting data off rivers or we make field observations. And I'm a big field person, as you know. But whenever you go to the field or whenever you take a survey or you get gauge data, you have to recognize that that represents a snapshot in time. Yeah. And what's happening when you get a survey today, that doesn't necessarily mean that the river was like that six months ago and it's not going to necessarily be like that six months from now. And I've seen cases. A really good example of this was on the Mississippi river. We often use the Mississippi for examples because we have a lot of data there. But back in the, I think it was in the eighties down near New Orleans, they had surveyed the river and they surveyed routinely because they have revetments, these articulated concrete mattresses that we put on the Mississippi river to stabilize the banks, protect the levees. They had seen that the original survey they had from like the 1970s when they put the articulated concrete mattress in. And then they came back in like May of 1984 and they surveyed it and it scoured 60ft, 60ft, 60ft from the toe of the mattress. It scoured down 60ft. So that scares the heck out of everybody. And they said, oh my gosh, we're going to lose the entire bank. Mattresses unraveling and we got a levee sitting up here. So they mobilize the troops, we go out and as part of this they're going to fix it, you know, put some more mattress down or some stone or something. And so they get a new survey a month later and it fill back in 40ft. And so first off, you think that must be a survey bus. No, it's not a survey bus. That's just natural variability in the river. But the real takeaway for me has always been that I go out and I get a survey. Am I getting it at. Getting it at the time that it was scoured 60ft or if I get it when it was filled in 40ft and I'm getting a completely different view of what's going on. So you always have to think about, when you look at your stream is where it is now, but where might it be, you know, what could do under extreme conditions or under, under different conditions? So it's just always a caution. And so the more data we get, the better we are. But more data is still subject to uncertainty and we have to be aware of that.

Stanford [00:35:33]:
A theme that's come up a couple of times is getting out to the river. Would you say that's part of your method and practice? Is that something you recommend for younger engineers?

David [00:35:43]:
Yeah, I do. We've got a whole group of, you know, young, young guys and gals here with us. Good group and. But that's any chance I get to go to the field, you know, we try to take them to the field because I feel like I learn more there than just about anywhere.

Stanford [00:35:58]:
Right.

David [00:35:58]:
Whether it's getting out on the Mississippi river, you know, in boats or going to the small streams and walking streams or floating them or, you know, get them in helicopters. I'm going to let them do all the helicopter work. Now. I've flown enough helicopters in my life. But I mean, to me it just, it grounds you. It really makes you realize, you know, just the dynamics and the variability in streams. I think about. I won't mention any names here, but this was back in the seventies when working with Brian Winkley, we had a professor, had his sediment model, okay. And he is just really wanting to come down. He knew about Winkley and we had the section 32 program going, so he wanted to come down and apply his model. So we had him come down, sent him out in the field with Bob Rinscher, the guy I talked about earlier, the geologist, and they went up to some of these north Mississippi small streams. And this professor looked at the stream and he says, the bank here is completely different than it is 100ft upstream. And then you got all this vegetation and there was a car body in the creek and, you know, how can I make this work in my model? And he got frustrated and went home and he went back.

Stanford [00:37:17]:
I love that the villain of this story is a modeler.

David [00:37:23]:
No names or mentioned. But I mean, the point is, you get in the field and you realize that just, it makes you question a lot of things when you see a lot of vegetation and debris. And so how do we capture that in models? And I think it makes modelers better the more they get in the field. I know you go to the field quite a bit.

Stanford [00:37:45]:
Well, but that's actually an intentional practice for me. Travis Dahl, who's just down the hall here, he and I were talking about this. There's like a maxim in geology that the best geologist is the one who has seen the most rocks. And he argued that there's just a matter of reps. And he argued that he thinks that maybe it's similar for river engineers, is that the best river engineer is just the one that's seen the most rivers. But for years, you know, I'm a modeler. So I just kind of stayed in my cubicle and I realized it's not even just about getting to the river, it's about getting to the river with someone who sees it. The descriptive sciences, they're a way of seeing the world. It's not a bunch of equations. It just is a matter of seeing the world enough times until you actually see the world. And so I take every chance I can have to go to the field with you or someone like Jim Selgan or any like, local expert who's just been on that river enough. And what I'll do is I'll just say, what are you looking at right now? At first, I wasn't even looking at the right things.

David [00:38:45]:
Sure.

Stanford [00:38:45]:
What I would call mentored reps is just getting out to the field with someone who knows the system and seeing what they're looking at. It starts to train you what to look at in your own systems.

David [00:38:55]:
I can remember when I first was working, as I mentioned, I went to the field almost every other week and I was going out with Bob Rensler. And at first we would go out there and we'd pull up to this bridge and there'd be a nick point up there. And he would talk about the head coating and this and that, and I'm like, well, what are you looking at? I mean, and I didn't know. I really didn't know. And I could see this waterfall there, but I didn't fully appreciate what it was doing, and I didn't understand how they moved, and so it took me a while.

Stanford [00:39:29]:
Yeah. I had the same experience with Matt Condolf. He was teaching a class up in Sage. Hence he took us out to the field into one of those Tahoe streams that's eroding. And he said, okay, here we are. This is the head cut. And everyone's like, oh, wow. And they started walking around like you do on a field trip. And I like, as soon as he was alone, I kind of sidled up to him and said, where's that cut? What's going on here? It was subtle because of this cobble, but he showed me what he was looking at, and those are the sorts of things I needed in order to be able to do it myself.

David [00:40:00]:
But it's. If you haven't been out there, it's not. It's not clear sometimes. And I try. I don't know if I'm successful or not, but when I'm out with, you know, some of the younger folks, I try to think back when I was there, and I didn't know what I was looking at. So I try to explain things as much as I can in the field. You know, when you're looking at vegetation or looking at the point bars and things like that, you know, what are you looking to. For and trying to identify bank full. That's, you know, that's a.

Stanford [00:40:30]:
That's an art. That's a craft.

David [00:40:32]:
That is a craft. But yet bank full in some design philosophies is the key.

Stanford [00:40:37]:
Yeah.

David [00:40:38]:
And if you don't have bank full, you don't have anything. And. But it's not easy to identify that. It makes me think about. And you're getting back to the interdisciplinary thing that years ago, I was working with a forester, and we were out in the field, and we were in a. In a overbank area, and we were walking around, and I'm looking down at my feet, looking at the sand, trying to see where the deposit, and he's looking up in the trees, and I realized, you know, we're looking at different places. But he was assessing the floodplain based on the vegetation types. I was looking at, you know, how much sand was being deposited, and, you know, looking for different things. But it got me thinking about that. It made me think more about the vegetation side of things. So, again, you can learn a lot from all kinds of different people at different stages of their career or different disciplines. So it's an important thing to remember.

Stanford [00:41:33]:
Okay, I have two final questions. And these questions are actually more about your professional approach than river mechanics or geology. It's more about how you do your work and became who you are. Because I'm actually really interested in that. I'm really interested in how do you become David Wiedenheart? That would be great. Here's the first one, is that I.

David [00:41:51]:
Have to ask my mother and father about that.

Stanford [00:41:56]:
You've built intergenerational teams as long as I've known you, and I've known you almost my whole career, because you put me on one of these intergenerational teams when I was 20. You actually took me to England at one point, and we had a lovely diversity of all the ways you could speak english language there, from Nottingham to.

David [00:42:15]:
I was the only person over there that nobody could understand.

Stanford [00:42:18]:
I did once have the experience of translating between Mississippi English and british English at a restaurant, which was fantastic. But later I saw this actually as a consistent practice, that you build intergenerational teams, and even now you're in a part of your career where your teams could be just composed of other senior experts who match your qualifications. You don't have to deal with the nonsense of Xers and millennials, but your teams now are actually younger than they've ever been. And you have people in every stage of their careers. And I guess my question is, like, is this intentional and what are the benefits of it?

David [00:42:56]:
It's somewhat intentional, but it's also somewhat just a factor of who's available at times, too. But I really like to have the inter generational type of teams because I like. Obviously, I want some experienced folks with me, but I like to have the younger folks, too. I feel like I learn a lot from them. And I'm not just saying that, you know, they don't maybe have the experience that maybe I've had. They haven't been doing it for 40 years. That's fine. But by the same token, they hadn't drunk from the same Kool Aid.

Stanford [00:43:31]:
That's right.

David [00:43:31]:
We've all. We tend to get in inner bread here somewhere, you know, and we start to influence each other and we, you know, but you get the younger guys and gals, they're not, you know, biased by all that stuff yet, you know, so they have some fresh, clean ideas sometimes. And plus, you know, like a lot of the folks work with now, the young, young folks are just, they're just smart as they can be and just. And, and they're all great folks. You know, I love working with all of them, but they do bring different perspectives, and so, and I ask them questions all the time. And I'm not just playing a part.

Stanford [00:44:09]:
There like Socrates, the socratic method to teach. You're like, legitimately asking them.

David [00:44:13]:
Yeah, because I'm curious. Because, I mean, and, and they'll argue with me, you know, and half the time they're right, you know, and, hey, that's fine, but that's, it's great. I think it's, you know, it's important. I wouldn't want to just work with all old guys like me. It wouldn't be nearly as fun. And plus, they bring a lot of skill sets that, with the new data sets that we have and a lot of the data that we can get now with Lidar and different things that I don't have the skill sets to get that to these guys. It's just like, oh, yeah, 5 seconds and they've done it. Or they can write codes to do things that it would take me weeks to do. They can write a code in 20 minutes and do it right then. And so there's that aspect, but that's not the code writing and the technical type of GIS capabilities. That's not the biggest thing they bring. It's the fresh approach and the new ideas and the ideas that hadn't been just drowned with our same old Kool aid. So that's what I do. I mean, I tried that, and I think it's keeps me, I like working with young folks, too, because they got a lot of energy and, you know, keeps me thinking young sometimes a little bit.

Stanford [00:45:32]:
All right, then, my last question. In the RSM proposal for this podcast, I described you as my first draft pick of guests that I would have on this podcast. You're the go to expert for mechanics and geom morphology among those of us, like in this agency who know the landscape. But I'm not sure I've heard another expert in anything say the phrase I don't know, or I'm not really sure. As often as I've heard you say it, I've never heard you assert your experience or authority. I've been in a lot of rooms where you were the guy that we should all be listening to, but you've never said, hey, I'm the guy you should all be listening to. And what you've done instead is often asked legitimate questions to help bring clarity to the situation. I guess what I want to know is I get the sense that humility isn't just like a character trait you have, but it's actually like part of the way you approach science. And I kind of want to know how that works. Like, how does your kind of personal approach, how does that inform the way that you think about the world and understand natural systems?

David [00:46:34]:
That was a big question.

Stanford [00:46:37]:
This is a question I've been wanting to ask you for a long time.

David [00:46:40]:
Oh, gosh, I gotta think of an answer. I'm not so sure that humility is part of my DNA necessarily. But when I say I don't know or I'm not sure, I'm usually I don't know and I'm not sure. And the longer I've worked, sometimes the less, the more I say that and less confident I am. Mentioned that before, right. And I think rivers are very humbling entities. If you work with them long enough, you're going to be proven wrong, and your ideas are of everything is not going to go the way you always thought it was. I mean, and so you become, you should become more humble as you get further into your career. Not everybody does. I know a lot of folks I've worked with over the years that were extremely confident, not and for no apparent reason sometimes, as I've said. But when I see that when, when the people have just absolute answers and they're just so confident and the answer is x, y, z, I've got warning bells going off in my head. So whenever I start to feel like I really got this thing nailed, absolutely. I've got warning bells going off in my head to say I kind of slap myself internally and say, think about this, you know, is, are you that sure? I'm not sure. I'm 100% confident and anything I've ever done in river engineering, but, you know, it's something that doesn't stop you from moving forward and making decisions, but it just makes you more cautious. And, and I think the longer you work with it, with rivers, you know, you should develop more of that cautious approach. So, I mean, that's, that's just kind of the way I look at it. And my, when I first get involved with the project, you know, I get this a lot. You know, people bring you in and they got a new project, and they give you a 20 minutes overview of the project on a phone. Now, because of COVID that's right. And they want to know your opinion. And half the time I'm going, I don't have an opinion, I'm thinking I've got to go look at this more. And I feel bad sometimes because I feel like they really want me to give them the absolute answer right there. You know, I've always want to go to the field and get more information and learn more before I give an opinion. But sometimes you just, you don't have the time. You've got to do things, but you always have to caveat.

Stanford [00:49:09]:
Yeah.

David [00:49:09]:
With what, you know, anything you say about, you know, any kind of conclusion, you make the problem. That is, sometimes it doesn't matter how many caveats you put on whatever you say, and you can say the, the answer is 3ft, but it's caution. There's uncertainty around this thing. It's probably somewhere between one and 5ft of scour that we're going to anticipate. But, you know, three is about an average, but be careful.

Stanford [00:49:38]:
Yeah, sure enough, the headlines, headlines 3ft. Beating harden says beaten heart says 3ft.

David [00:49:44]:
And let's move on. And that happens all the time. I know it's happened to you. Yeah, for sure. But that's just part of the world we live in.

Stanford [00:49:51]:
Well, David Beanhard, thank you so much for spending this time with us. I have to admit that part of my objective of doing these is just being able to have conversations like this. And it's been a pleasure.

David [00:50:02]:
Well, hey, this is fun. I was scared to death when you told me you wanted to do this, because believe it or not, I'm not the person who just loves to get up in front of a camera or get a microphone in front of them. I know that it's just something I have to do sometimes. But you made it as a conversation and you and I have had a lot of, a lot of conversations over the years and I always enjoyed that. So I appreciate the way you handled it.

Stanford [00:50:25]:
I think that part of what I wanted to do with this whole thing is just give other people a chance to be in the room while we have those conversations. I appreciate you.

David [00:50:34]:
As long as you don't show in my room, all the clutter and my collapse bookcases and stuff.

Stanford [00:50:40]:
All right, well, thanks a lot, David.

David [00:50:41]:
Thank you, Sam.

Stanford [00:50:46]:
And with that, we will wrap up season one. Thanks for joining us for this little experiment and thank you to all the guests who took their time to share their insights with us. As I mentioned in the intro, this channel will probably go quiet for about eight to ten months as I record the second season. I am mostly recording these opportunistically when my work travel takes me near or through a location where I can talk with someone. So season two will take a while. But we're really excited about everything that we've already recorded, booked, and planned, including some experimental episode formats and conversations with some of the guests that you've requested. And if you'd like to make one of those requests to recommend guests or recommend papers, I have a Google forum on the podcast website that's linked in every episode description. Or you can reach out to me with feedback on LinkedIn Researchgate or on the HCC sediment YouTube channel that is hosting the podcast videos. And if you haven't been to the website, we've collected videos and links for each episode there. It is worth stopping by. I'm also really interested in any feedback you have on season one. This was incredibly fun and if the download stats are an indication, many of you also found it valuable. But I'd like to make season two better. So if you have any thoughts on any aspects of what we're doing here, whether it's interview style, audio or video tech, episode length, video shorts or ideas on experimental episode formats. Let me know if there's a podcast that does a thing that you like that you think would work well for what we're doing here. Reach out. I'd love to start cranking the learning cycle and implement any actionable lessons before I get too deep into recording season two. Finally, thank you to the regional sediment management R and D and Tech transfer program for supporting this project. As probably came out in my conversation with Katie, I really appreciate RSM's vision to just do better, better in every part of sediment management. From dredge schedules, which I know nothing about, to more natural river management approaches to something like this. Exploring tech transfer opportunities I'm always proud to be part of the Coors RSM program. And thank you as always to Mike Loretto for editing and mixing this season, writing the music, and frankly, coaching me along the way. These are informal conversations and the views expressed do not necessarily reflect the positions of the US Army Corps of Engineers. Their partners are the offices or centers of the guests or host. Thanks for joining us.