In this episode, I talk with Dr. David Beadenharn, a river engineer who has spent over 45 years studying the lower Mississippi River. David grew up in Vicksburg, Mississippi, stumbled into river work after leaving the Air Force, and never really managed to leave.
Our conversation starts with a picture of what the Mississippi looked like a couple hundred years ago, when the river was wide, shallow, full of sandbars, islands, and massive logjams. Back then, the river was constantly on the move, eating away at its banks and shifting course. That erosion was producing an almost unimaginable amount of sediment — around 600 million tons a year. In comparison, the river today carries somewhere around 120 to 150 million tons.
Then we transition to the engineering projects. The Army Corps of Engineers has spent decades trying to get the river under control — first for navigation, then for flood control after the catastrophic 1927 flood. They built levees, tried to stop the river from naturally shortening itself, and eventually decided to deliberately cut off some of those big sweeping bends. The immediate effect was dramatic — water levels at some spots dropped 10 to 15 feet almost overnight.
But shortening the river made it faster and more powerful, and the Mississippi started scouring its own bed looking for more sediment to carry. That process is still rippling through the system today, decades later, slowly working its way upstream toward Cairo, Illinois.
On top of the cutoffs, the Corps locked the riverbanks in place with concrete mattresses in the 1950s and 60s, essentially freezing the river’s shape. That stopped the bank erosion — but it also cut off the river’s natural sediment supply almost entirely.
David’s big takeaway after all these years? You can’t just fix one spot on a river and call it a day. Every change you make sends ripples — upstream, downstream, decades into the future. The Mississippi has a long memory, and it’s still responding to decisions made 80 or 90 years ago. Understanding that complexity, he says, is what keeps him coming back to the river year after year.
Show Notes
US Army Corps of Engineers, Engineer Research and Development Center (ERDC)
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Transcript
Mon, Jun 01, 2026 5:22PM • 1:18:13
SUMMARY KEYWORDS
Mississippi River, hydrology, flood control, sediment load, meander cutoffs, levees, channel response, stream power, river engineering, geomorphic assessments, navigation channels, erosion, aggradation, degradation, river management.
SPEAKERS
Dr. David Biedenharn, Dean Klinkenberg
Dr. David Biedenharn 00:00
And so when we look at the river pre 1930s it was a completely different river regime than what we have today, it was, it was more islands, bars dominated, dominated system, log jams, it was it was it was a mess, it was wide, shallow, more shallow, and maybe slightly aggradtional, maybe slightly building up. So that was the river that we had in the 17, 1800s as the nation was growing and trying to use this this river for navigation.
Dean Klinkenberg 00:58
Welcome to the Mississippi Valley Traveler podcast. I’m Dean Klinkenberg, and I’ve been exploring the deep history and rich culture of the people and places along America’s greatest river, the Mississippi, since 2007. Join me as I go deep into the characters and places along the river, and occasionally wander into other stories from the Midwest and other rivers. Read the episode show notes and get more information on the Mississippi at MississippiValleyTraveler.com. Let’s get going.
Dean Klinkenberg 01:30
Welcome to episode 78 of the Mississippi Valley Traveler podcast. Well, as this episode goes out, we are in the second week of River Days of Action. I’m hoping you’re all finding a good way to celebrate the river, maybe give a little bit back to the river, but certainly spread the word about the joys of spending time along the Mississippi River, and why it’s such a special place. If you’re looking for ideas on things you can do during the remaining days of River Days of Action, head to MississippiRiver.org and you’ll find a complete schedule there.
Dean Klinkenberg 02:06
So, in this episode, we are going to take a deep dive into the dynamics of the lower Mississippi River with Dr. David Biedenharn, who’s a professional engineer and has spent over 45 years of his career trying to understand the dynamics of this mighty, mighty river, the Lower Mississippi. He’s a Vicksburg native, and we talked briefly about his history growing up with the river and what it meant to him as growing up. Then we get into some of the basics of how river engineers approach trying to understand the flow and dynamics of this mighty river. We talk about the historic flow characteristics of the Mississippi, for example, and how we’ve changed it through the engineering structures. The river’s sort of fundamental push toward equilibrium, and how that plays out. We go into some depth talking about meanders and how they develop and what they can tell us about the river state. We talk about the concept of stream power, what that means in engineering terms, and engineers, and we talk some about the river’s sediment load and factors that influence the size and volume of sediment carried by the river, and why that matters.
Dean Klinkenberg 03:14
Then we’ll spend a little bit of time talking about the history of flood control in the Lower Mississippi, and how those efforts have altered the river, and how the river has often responded to our attempts to confine it into a narrower channel by finding other ways to meet its needs for equilibrium. At least, as I understand it,. This is not my specialty, but I really enjoyed talking with David about this stuff. I have a feeling we could go on for a long time into the depths of this, but I think this is a really good general introduction, and he does a great job explaining these concepts and explaining them in a way that I think, if I can understand it, I assume just about anybody could.
Dean Klinkenberg 03:54
As usual, thanks to those of you who show me some love through Patreon. Your support keeps this podcast rolling along. If you want to join the Patreon community, go to patreon.com/deanklinkenberg. You can join for as little as $1 a month, and that gives you early access to these episodes, as well as just the satisfaction of knowing you’re helping keep this podcast alive. Patreon, not your thing. Yeah, you can buy me a coffee. Go to MississippiValleyTraveler.com/podcast and from there you’ll find out how you can buy me a coffee. And at that same place, MississippiValleyTraveler.com/podcast you will get access to all previous 77 episodes. You can pick and choose an episode to listen to, or you can just go crazy and binge them all if you wish.
Dean Klinkenberg 04:43
And let me just remind folks, as this goes out, that the Kickstarter campaign for my new book, a travel memoir called ‘Better Safe Than Sorry: Slow Boats, Chicken Busses, and the Radical Choice to Trust the World,’ the Kickstarter campaign for that is just about to go live. You can currently sign up for a pre-launch page, where you’ll be notified as soon as the campaign goes live, or you can wait till June 15 when it goes live, and then you can go there and buy yourself a copy of the book, if you wish. If you’re interested in more, go to DeanKlinkenberg.com/BetterSafeThanSorry.
Dean Klinkenberg 05:23
All right, let’s get on with the interview. Dr. David Biedenharn is a professional engineer with over 45 years of experience in hydraulics, river engineering, sediment transport, and fluvial geomorphology with the US Army Corps of Engineers, Vicksburg District, specifically the Engineer Research Development Center, or ERDC, at the Waterways Experiment Station in the Lower Mississippi Valley Division Office, as well as with the Biedenharn Group. He’s presently a research hydraulic engineer with the River Engineering Branch at ERDC. His work experience includes the hydraulic design of flood control and navigation channels, levees, geomorphic assessments, bank stabilization measures, and grade control structures, channel restoration projects, and regional sediment management, and we will get into some of these topics specifically in just a minute.
Dean Klinkenberg 06:25
David, welcome to the podcast.
Dr. David Biedenharn 06:28
Thank you, Dean. It’s really good to be here today.
Dean Klinkenberg 06:31
Why don’t we just kind of start with a step back and tell me how you got interested in the Mississippi River in the first place?
Dr. David Biedenharn 06:37
Well, I actually grew up in Vicksburg. So I’m from Vicksburg. Never thought I would end up staying here for most of my life, but I joined the Air Force in 1969 and when I got out in 1973 the Corps of Engineers Vicksburg District was hiring at that time, so they hired me as a hydrologic technician, and I was actually doing sampling on the Mississippi River, sampling water and sediment, and also a lot of the smaller tributaries. So that was my first real, I guess, introduction to the Mississippi River. Other than when I was in high school, it was a place to go and boat and drink beer and have a good time. But, so that was my first step into the river and got me interested in it, and then I went back to school and I got my engineering degree, civil engineering, and I came back to work for the Vicksburg District and I was working in what was known at that time as the potamology section and I imagine there’ll be a lot of people wondering what potamology is.
Dean Klinkenberg 07:46
Including me.
Dr. David Biedenharn 07:47
Yeah, exactly. I mean, and potamology is the science of rivers, and at that time, in the late ’70s, I was working for a man named Brian Winkley, who was my mentor. He’s the one that really got me interested and excited about rivers, and basically at that time we were trying to understand how the Mississippi River was responding to everything man and nature had thrown at it over the last several 100 years, and so that’s how I really got started looking at rivers, and then I branched out into doing a lot of small stream work as well, and then after about four or five years they changed the name of potamology, because nobody knew what it was, and we started calling it river engineering, so now it’s the river engineering groups, and I’m still working in river engineering today, so that’s really how I got interested in it, and, and it’s, it’s been kind of a passion of mine. I actually retired from the Corps almost 20 years ago, and I ran my own engineering company for about nine years, and then one day I realized that I had this real jerk for a boss, and that was me. My wife said, “You need to do something different,” and I had the opportunity to come back to work at ERDC here in Vicksburg, and I’m getting to work with all the young engineers and scientists here, and I’ve been doing that for the past six years, and this, and it’s really a lot of fun. It keeps me going.
Dean Klinkenberg 09:29
I don’t think you’d be the first person in history who started doing some work on the Mississippi, and then had a hard time stepping away from it.
Dr. David Biedenharn 09:36
Yeah, it’s not, it’s not easy. I can, I can attest to that.
Dean Klinkenberg 09:41
Well, one of the things I’m interested in is sort of looking at the river, the lower river in particular, before we started making a lot of changes to it, and then how the engineering has affected that river, and it seems like that’s a bit, as you just hinted, is sort of a big part of the work that you’re doing. Why don’t you start by painting us a picture of the river a few 100 years ago?
Dr. David Biedenharn 10:06
Okay. Well, if we look back, and I’ll talk about the. I’m really going to be focusing on the Lower Mississippi River, which is really starts around Cairo, Illinois, where the junction of the Ohio and the Middle Miss come together, and so that’s the area the river I’ll be focusing on today, and really from Cairo down to about Old River, and that’s where the Atchafalaya, the Mississippi diverts out into the Atchafalaya, and then flows on down through Baton Rouge in New Orleans, and there’s a, that’s a whole nother river downstream of Old River, and maybe we’ll leave that for another day, and maybe another person to discuss that. But that’s the reach of the river I’m going to be talking about today.
Dr. David Biedenharn 10:55
And if we look back in time over the last 6, 7, 800 years from Cairo to the Gulf, the Mississippi River had an approximate length of around 1100 miles, and it’s interesting when you look at those changes every, every century they had, they had mapping that they could estimate the length, and it would, it would gain in length through some periods, they would lose length in others, but it, it hovered around 1100 miles. It might, it might increase 50 to 75 miles in one one century, then decrease again, but it maintained that length, and it did that by meandering, and that’s how rivers actually maintain their health, but when I say meandering, I’m talking about, you know, the outer banks of the river are eroding, and the river is migrating laterally, point bars are building, the floodplain is getting sediment in there, and what happens through time as that river meanders is gaining length, it’s getting longer. But then they’ll make, the river will make natural cut offs, and we’ll call these neck cut offs, and these – this is where the river cuts across the neck of the of the bend, and it leaves these old large oxbow lakes that you see in the floodplain, so the river may be shortening in one area and lengthening in another, but overall it was trying to maintain the same length over that time period.
Dean Klinkenberg 12:29
Just for clarity, to when we say 1100 miles in length, we’re talking about river miles, not as the crow flies, right?
Dr. David Biedenharn 12:35
Correct, 1100 river miles, yes, the but the channel is trying to keep that same length, and if you think about it, it has the same elevation drop from Cairo to the Gulf, so it’s trying to maintain its slope, and that’s where we get into this whole question of sediment and the movement of sediment through streams that is a function of the the energy in the river, which is what we call stream power, which comes from just the how much water is moving in the channel, how many, how many million cubic feet per second is passing Vicksburg, you know, per second. And then what’s the slope of the river, so the product of the discharge, the water, and the slope of the river is what we call stream power. That’s where the energy of the river, where it gets its energy to do work, and by do work, it can cave the banks, it can scour the bed, it can move sediment. So that’s when we think about sediment and all the things we’ll talk about on the Mississippi over the next couple 100 years, it’s going to be related to how that stream power is changing and the movement of sediment. So, the higher the stream power, the more slope you have, the higher the discharge, the more sediment that it can move. We can get, we could drill into the details of that, but I don’t want to bore people too bad right off the bat, but that’s the, but that is the way getting back to this link, that’s the way the river maintains its, its health and its stability. If it, if it has just the stream power to move the sediment that’s coming into the river, then it’s not going to be filling up with sediment, and we call that aggradation, or it’s not going to be searching for more sediment and scouring the bed and the banks and enlarging, that’s called degradation. And so it’s sort of in a balance, it’s balanced that stream power with the sediment supply coming into it.
Dean Klinkenberg 14:42
I was thinking, too, like part of what must be another variable in this factor is the nature of the soil that the river is passing through, like if the river is passing through rock, obviously that’s different than dirt, but can you describe sort of what the soil context is like for that section of the Mississippi?
Dr. David Biedenharn 15:05
Right, in fact, that’s exactly the next part of this relationship. This balance is not only how much sediment is moving, the load, and we usually call that the sediment load, and that might be measured in tons per day of sediment, but the other part of that is, what size sediment is it? Is it moving sands, gravel? It’s like the Mississippi River that we’re talking about. The dominant dead material that we have out in the stream is going to be fine, medium core sands and gravels. If we go up into the mountainous streams, it may be moving gravel, cobbles, boulders, so all streams are different, but they’re all trying to, they’re all related to this stream power and sediment balance, but the sediment size plays a big part of that, for sure.
Dean Klinkenberg 16:02
And historically speaking, Where did most of that sediment in the Mississippi come from?
Dr. David Biedenharn 16:11
From the watershed all the way to the mountains. I mean, the Mississippi River drains, I think, 41% of the United States. So all that sediment, you know, from the watershed comes in, coming from the watershed itself, from the tributaries, and then it’s in the floodplain itself, and the river is meandering through that floodplain over 1000s of years, you know, reconnecting with older sediments and moving that through, so it’s a complex mix from a lot of different sources, but to understand how rivers behave, we have to think about those sources. Where is that sediment coming from? How is it moving through the channel itself to to where it ultimately drops out in some place that we might call a sink area. It could be the Gulf, or it could be in a reservoir boundary or it could be in the channel itself.
Dean Klinkenberg 17:06
So if we were going to pick a point along the Mississippi, let’s just say, like Memphis, like a couple 100 years ago, about can you ballpark like about what percent of the sediment passing by that spot a couple 100 years ago might have come from the Missouri River and the Great Plains versus how much would have been picked up locally?
Dr. David Biedenharn 17:28
The short answer is no. I should say the honest answer would be no. It’s, it’s with everything you know. We joke about this a lot, we teach a lot of classes in river engineering, and, and oftentimes the answer is, and this irritates a lot of engineers, but the answer is, it depends. We found that it’s often the best answer. It could be a lot of the, and this, this gets into the, the type of sediment load, and without getting into too much detail, there’s sediment that we call wash load, and this would be the very fine sediments. If we think about the Mississippi River, say at Memphis, the wash load would be those fine sediments, silts, clays, very fine sands that are pretty much in suspension all the time that don’t really settle out in the channel itself to any appreciable amount. They may deposit when it gets into the overbank flood plain or into some side channels, but for the most part that sediment is is purely a function of the supply, what’s coming in from upstream, and in that case, some of that sediment could, could be coming from the Missouri River, because it moves through the system very quickly.
Dr. David Biedenharn 18:51
There’s also what we call bed material sediment load, and that’s the sediment load that’s made up of the sediments that make up the bed of the river, and that would be the coarser sediments in Memphis, that would be fine, medium course sands, maybe some gravels, and it’s that bed material load that moves much differently than the wash load, because it’s moving as a result of the energy of the stream, it moves slower and that is the load that we focus on when we start thinking about channel response to some alteration we do in a river system. If we make a change in a river system, we’re thinking about how that affects that that coarser sediment, whereas the wash load is really not, not figured into that calculation, to is it’s only to a limited degree. So there, and it’s, it’s not often, it’s not always easy to differentiate sometimes for what’s wash load and what’s bed material, but in general at the 100,000 foot view, you could say the silts and clays and very fine sands just move through the system until they hit down below New Orleans somewhere, then they drop out. And whereas the bed material is that coarser sediment, so that bed material sediments at Memphis 200 years ago was probably sourced from just upstream coming in the channel itself, because that sediment is not moving as far or as fast, and again I hesitate to get into too much more details about bed material and wash load, but it is a critical component of understanding sediment loads on the river, because they’re completely different loads, and the river system reacts differently to both of those.
Dean Klinkenberg 20:48
Right. And I guess, like, you know, flood events, you know, flood pulses would have a big impact too on what sediments are being carried and where they’re dropped. And I guess with that earlier question, kind of what I was thinking too, is I remember seeing charts that kind of compare what we believe the historic sediment load of the Mississippi was before the Missouri River was dammed up the way it is today, and what that sediment load looks like today, and it sort of implied that the bulk of the sediment was coming down the Missouri River. It seems like you’re saying maybe there’s some truth to that, but it’s more complicated than that too.
Dr. David Biedenharn 21:28
Yes, that’s exactly the way I would say it. There is truth to that. There is that, is that’s a very widespread figure. I think I know the figure you’re, you’re talking about. I think that it’s, I think they call it a Secchi diagram or something, but it’s kind of like Napoleon’s march from Russia, how they, you know, it got smaller and smaller as he got toward, you know, Paris, whereby all the soldiers dying off. Well, they show the same thing with the Mississippi with that, that chart, the width of the of the chart, you know, kind of describes the amount of loads, and and these are these are estimates that have been made based on measured suspended sediment data in the river, and they have a lot of people have documented this and shown that the sediment loads on the Mississippi River have reduced anywhere from 50 to 85% today versus what they were maybe 60, 70 years ago.
Dr. David Biedenharn 22:33
And when you look at that data, that is correct, that is, that’s what the data shows. Where it get and so that suggests that there’s a significant decreased load sediment load on the Mississippi River today, and while that is true, we have to think about what sediments we’re talking about there, and that’s rarely discussed, and this is these estimates all come from measured suspended sediment data, which is, which is really good data. We use it all the time on rivers all over the world, but it’s, it has a limitation that most of it typically they’re capturing that finer sediment load, the silts, the clays, maybe the very fine sands, and it’s not a very good, in my view, a very good representation of the bed material load on the river, and we can, I can talk about this later, but in my view, as a result of a lot of things that have happened to the river, which we, we can discuss in a few minutes, that the stream power on the Mississippi River today is much, much higher than it was 50, 60, 70 years ago, and therefore I believe that the actual bed material loads, that coarser sediment is actually there’s higher loads of that today than there were 60 or 70 years ago. But maybe we’ll, we’ll hold off some of that discussion to later after we talked about why I believe some of those loads might be higher.
Dean Klinkenberg 24:14
Yeah, go for it. Go ahead and get into that.
Dr. David Biedenharn 24:17
Okay. Well, let me just start, kind of walk through, take us from where the river was maybe a couple of 100 years ago to where it is today, because there’s a lot of things that have happened to it, and I think if we’re going to understand the Mississippi River, we need to understand where it was and how it got to where it is today. And so if we look back, some of the I’m really going to start, maybe in the late 1700s, that’s 1765 is one of our first mapping of the Mississippi River, and we have others in 1820s, 1890s, and so forth, and we can compare the river through those time periods to see how it’s changed, but I think about this, this, the early 1800s that’s about the time that our nation was expanding in into the to the western part of the nation, and in a way we kind of picked a bad time to move into this area, because the Mississippi River in 1811, 1812 we had what is known as the – I’m sure you’re aware of this – the New Madrid earthquakes that really just shook the heck out of the Mississippi River. Supposedly it rung the church bells in Boston. I’m not sure about that, but we had anecdotal information that you know, islands and bars just completely disappeared. It just shook the heck out of the system as far down as Vicksburg. The river flowed backwards and created lakes, introduced a heck of a lot of sediment into the river system.
Dr. David Biedenharn 25:58
So, right off the bat, we’ve got Mother Nature working against us a little bit, and then we think about all the boats that were navigating the river back in 1800s, the steamboats. Most of these were wood burning steamboats, and for a lot of reasons, because there was plenty of locations to get that fuel all along the river, and so you can look at a lot of the old maps from the 1800s and you’ll see they’ll mention these wood yards that grew up all up and down the river, and these, these folks would actually go clear all the trees off the banks, put them on barges, float down into the river, and sell it to some captain going up or down the river, and they pull back in, cut some more trees, and so they were completely denuding the banks of the river at that time, which were were taking away some of the vegetation, which kind of helps with some of that bank erosion, and at the same time some of the banks were being cleared for agriculture. If people wanted to farm up on the natural levees around the river, which were higher ground, so they’re cutting all the trees, so we’re removing all the trees, and so the river was extremely dynamic at that time, and some of our studies here in the last several years, we looked at some of those historical surveys from the 1700s, 18 to 1930s and only on up to present day, and one of the things we found, and when we looked at the meander migration, how, how fast, and how what kind of rate of erosion these meander bins had, they could range anywhere from 30 an average of 30 feet per year to close to 100 feet per year, and that’s just an average.
Dean Klinkenberg 27:48
Wow.
Dr. David Biedenharn 27:49
And as a result, we made some calculations of how much, how what the total volume of sediment being eroded from the stream banks between Cairo and Baton Rouge was in that pre 1930s period, and it was about 600 million tons per year. And I think 600 million tons, I can’t even get my head around what, what that number means, but if we look at the total measured suspended loads on the Mississippi River today, say, you know, at Vicksburg or somewhere, is probably 120 to 150 million tons per year. So this was one heck of a lot of sediment that was being generated from those that bank caving, and where does that sediment go, and that gets into that sources the pathways and sinks again. A lot of that, a lot of that sediment coming out of the banks would have been fine sediments, silts and clays, and that could have been just pushed into the river and transported quickly downstream to the Gulf, or somewhere, you know, close to that. But a lot of that was coarser sediments, the bed material size sediments that would be deposited on the bars, and so when we look at the river pre 1930s it was a completely different river regime than what we have today. It was, it was more islands, bars dominated, dominated system log jams. It was, it was, it was a mess. It was wide, shall more shallow, and maybe slightly aggradational, maybe slightly building up. So that was the river that we had in the 17, 1800s as the nation was growing and trying to use this river for navigation. I often like to read Charles Dickens’ quote. I don’t know if you’ve read that he made a trip down the Mississippi River in 1840s. I don’t know, Dean, if you had a chance to read that before.
Dean Klinkenberg 30:01
I am familiar with that. Yeah, go ahead.
Dr. David Biedenharn 30:04
Yeah, well, I’m not going to read the whole quote, but I will pull an excerpt or two from it. And this was just his impressions, and they weren’t really good impressions.
Dean Klinkenberg 30:14
He wasn’t exactly a big fan.
Dr. David Biedenharn 30:16
No, no, he was not. I’ll just read you a few things, but it really does. It gives a very good description of what the Mississippi River was like back in that time. So that’s why I like to read it. I wish I could do it with a good English accent, then my IQ might go up about 10 or 20 points, but but he says, “at the junction of the two rivers,” and he’s talking about the Ohio and the Middle Miss, there around Cairo, “lies a breeding place of fever, ague, and death, a dismal swamp,” says, “a place without one single quality in earth or air or water to commend it, such as this dismal Cairo.” He says it’s “an enormous ditch, sometimes two or three miles wide, running liquid mud six miles an hour is strong and frothy current choked and obstructed everywhere by huge logs and whole forest trees now twining themselves together at great rafts. For two days we toiled up this foul stream striking constantly against the floating timber or stopping to avoid those more dangerous obstacles, the snags or sawyers, which are the hidden trunks of trees that have their roots below the tide.” Well, obviously, there’s a little sarcasm in Dickens’ view of the river, but I like that quote, in that it really describes what our rivers looked like back then. And it was, it was wide, more shallow, bars, islands, just debris, log jams all through it, and that’s the river we were trying to maintain for navigation at that time.
Dean Klinkenberg 32:02
If I’m kind of understanding you correctly too then, it sounds like you’re almost arguing that this was kind of an exceptional period in the river’s history, that because of combination of factors, including the New Madrid earthquakes, the deforestation along the riverbanks, that we kind of created or had created this river that was particularly difficult to navigate in that period of time, and maybe 100 years before that, maybe the river characteristics might have been a little bit different, or maybe not quite as unfriendly to boats.
Dr. David Biedenharn 32:36
Yeah, it’s hard to say exactly, but you raise a really good point that’s been discussed a lot, that when we compare, for instance, sediment loads again, we’re saying sediment loads today are 80% less than what they were 100 years ago. Well, it could have been that the sediment loads 100 or 200 years ago were accelerated, they were higher than normal, can’t say that, you know, with any certainty, but obviously there were other things going on in this period, and I think it was obviously prior to that the river was very dynamic, obviously, but this could have been a been the stability or instability could have been exacerbated by some of these, the deforestation and some of the natural, the New Madrid earthquake, and some of these things.
Dr. David Biedenharn 33:27
So, I like saying it was a tough time to be thinking about trying to navigate the river. If you read Mark Twain, you really understand that. And, but what. So, the Corps of Engineers was involved with this, and then in 1879 they formed the Mississippi River Commission, which was a commission. It was actually located here in Vicksburg, and the it was the MRC was given the charge of managing the Mississippi River for navigation. We’re really only talking about navigation at that time. Flood control was not really part of the authorization here.
Dr. David Biedenharn 34:10
So, when the Mississippi River Commission started looking at how are we going to maintain this river for navigation, they considered a lot of different approaches, and they looked at building levees, and the idea there was they could build levees and restrict the river and not allow it to break out or crevasse down into some of these outlets, they would keep all the energy in the channel system itself, and not let the water escape through these, these crevasses. Then they could keep the channel self-scouring, was was the idea there. That was one of the alternatives. They also considered it maybe going up and building reservoirs, dams to reduce some of the flow. They looked at some outlets, they thought about, you know, maybe providing some outlets in different places, and probably the most controversial discussion was the making meander cutoffs, and so, as I understand it, there was some pretty heated discussions and arguments about what the approach was, and in the end, the MRC settled on what is known as the “levees only” policy, and maybe I’ll discuss this in some previous podcasts, I’m not sure. And basically, as I said, the idea there was keeping more of the energy within the levees to keep the channel self scouring, so they wouldn’t have to dredge as much to keep the channel open for navigation. And that was in the 1880s that they established that.
Dr. David Biedenharn 35:55
A lesser known part of that policy, well, they actually had a “no cutoffs” policy and I think that grew out of this debate about having cutoffs on the river, and cutoffs are a lightning rod for debate among river engineers, because there’s pros and cons to making artificial or man-made cutoffs. I’m not talking about natural cutoffs. And the advantages are you can actually increase the slope, and you can have more of a getting the water out faster, you can scour the channel, and the negative aspects is you increase the slope, and you have scouring, and it also can create what we call head cutting, and head cutting is where the over steep and degradational zone in a river migrates upstream through time, and as it’s doing that, it’s pulsing more and more sediments, bed material sediments downstream, which aggravates the aggradational problems, so there was a lot of that debate, and I think because of that they decided we’re not even gonna allow the river to make its own natural cutoffs, and so from 1880 to 1929 the Corps did not allow the Mississippi River to make any natural meander cutoffs. These neck cutoffs.
Dean Klinkenberg 37:27
How would it physically intervene to stop that?
Dr. David Biedenharn 37:30
Yeah, the, you know, we didn’t have some of the techniques that we have today with the art, the articulated concrete mattresses, but what they would do, they would come into a meander bin, and where they knew that it was getting close to a cut off, and they would come in, and they would build these, these willow mats, woven willow mats that they would weave together 1000s and 1000s of willow trees into a mattress along the bank, and then they would sink it with stone to sink it down onto the stream bank. And that was actually a very successful technique, and these mattresses, if you keep, you keep wood submerged and wet, it can last for an awfully long time, and so that’s the way they did it, and so between I think 1880 and 1929 there were no neck cutoffs, natural cutoffs on the Mississippi.
Dr. David Biedenharn 38:36
Interesting enough, and this has always fascinated me, so you think about it, we didn’t allow the river to shorten itself, and it was continuing to erode and meander in other places, so you would think that the river would be much longer in 1929 than it was in 1880 when we stopped it, and the thing is, it wasn’t. And the reason is there’s another type of cutoff we call a chute cutoff, which is where the river just widens out a bit, and the channel will will make a shortcut across the point bar, and that’s called a chute cutoff. And whereas a neck cutoff might, a single neck cutoff might remove 20 miles from the stream, a chute cutoff might only remove a mile, shorten the river a mile, maybe two miles, three miles. But what happened, they didn’t stop the chute cutoffs, and the the number of chute cutoffs went up dramatically during that time period, and I always kind of think of that as Mother Nature saying, “all right, guys, I’ve got a bigger dredge than you do, you’re trying not to let me make these cutoffs, I’m going to go ahead and shorten it up because I need to keep my slope, you know, in the right, you know, regime,” and so it actually increased the number of chute cutoffs by almost a factor of three, and that by 1929 the river wasn’t much longer than it had been in 1880. So I guess it’s sometimes, you know, not nice to fool with Mother Nature, she’s, she can, she can overwhelm us sometimes.
Dean Klinkenberg 40:17
But it’s a fascinating dynamic, because it sort of suggests this overall, or this systemic homeostasis, like there’s a, there’s a balance in place in this whole system, and maybe you’ll touch on this a little bit later too, but like when you start monkeying around a little bit with the dynamics in this one area, then there are reverberations throughout the entire system.
Dr. David Biedenharn 40:40
Yeah, we’re going to talk a lot about the system.
Dean Klinkenberg 40:44
Before we get too deep, as I thought, I want to come back to the cutoffs, because there were cutoffs before 1880 though, right? Like Henry Shreve famously was his the first cut off?
Dr. David Biedenharn 40:55
No, they’re maybe one of the first artificial or man-made ones.
Dean Klinkenberg 41:00
Right.
Dr. David Biedenharn 41:00
Natural cutoffs, they, the Mississippi averaged about 15 natural cutoffs every century. Just that’s just an average, so that’s that’s kind of the natural sequence or frequency of cutoffs that the river had, and so these were always occurring, and then, like you say, Captain Shreve and others made some cutoffs down Roanoke River and other places, so there were some of those there, so there were some artificial cutoffs before these, these in 1930s which we really haven’t talked about too much yet, so.
Dean Klinkenberg 41:42
Hey, Dean Klinkenberg here. Interrupting myself. Just wanted to remind you that if you’d like to know more about the Mississippi River, check out my books. I write the Mississippi Valley Traveler guidebooks for people who want to get to know the Mississippi better. I also wrote “The Wild Mississippi,” a guide that goes deep into the complex ecosystem supported by the Mississippi, the plant and animal life that depends on them, and where you can go to experience it all. If you like fiction, check out my Frank Dodge mystery series. Each book is set in places along the Mississippi River. My newest book is a travel memoir called “Better Safe Than Sorry: Slow Boats, Chicken Busses, and the Radical Choice to Trust the World.” The book explores a simple question: What happens when you stop asking what if something goes wrong and start asking what if everything goes right? Find out more at deanklinkenberg.com/bettersafethansorry.
Dean Klinkenberg 42:43
So the in that debate, then around 1880 when the Corps is deciding not to do any more artificial cutoffs, were those earlier cutoffs in their minds, was that where they was something about those cutoffs prescient for them that they caused them worry about doing more?
Dr. David Biedenharn 42:59
You know, there was there was a quite a bit of literature all around the world, European experiences with cutoffs, and I’m, and I guess I should be clear, I’m talking about their concern at that time, their debate was about making artificial or man-made cutoffs. And so there had been quite a bit of knowledge about the impacts of cutoffs, and that’s what they were debating. But I believe what happened with their “no cutoff” policy, they, they took that even further and said we’re not only going to not going to make artificial cutoffs, we’re not even going to let the natural cutoffs occur.
Dean Klinkenberg 43:41
All right, so all right, so take us to the next chapter, then.
Dr. David Biedenharn 43:44
Yeah, okay. Well, I gotta remember where I was now.
Dean Klinkenberg 43:49
I guess we’re probably post 1927 flood at this point.
Dr. David Biedenharn 43:53
We’re getting to that. So we’ve got the levees only policy and no cutoffs, and then everything really was moving along pretty well until the 1927 flood. And I know that you probably had discussions of the 1927 flood. It was one of the worst natural disasters in our country’s history. Hundreds of thousands of people were displaced, several hundred people, probably more than that, were were killed. It was a, it was just a major event, and, but what it did, it kind of galvanized the country, and really started us thinking more about the systematic approaches for flood control, as well as navigation. We started moving into flood control a little bit before that, but as a result of the 1927 flood, there was the 1928 Flood Control Act, and in that act they created the Mississippi River and Tributaries Project. And that is the authority and the projects, the project that we’re actually working under on the Lower Mississippi River today. So that’s the genesis of that project.
Dr. David Biedenharn 45:07
When they started thinking about this, what would the MR&T project entail, again they had to start thinking about all these other options, and because now they’re talking about flood control and as well as navigation, and so they looked at a lot of different features, and they started thinking about more of a comprehensive approach. And so they incorporated four major components to the MR&T project. They included levees, so they recognized levees were definitely kind of the the backbone from a flood control perspective, they were going to have to have levees. Then they also included some floodways, allow some some water to go out at certain locations, and they also gave authority to work up into the tributaries, which was, which was a first for the river, too. So now they could go up and work into the tributaries themselves. And then the big change was the channel improvement features, and the channel improvement features included all the work in the channel itself, and that that included revetments. We’re going to talk about that in a minute, the dyke systems, local maintenance, dredging, and the cut off program of the 1930s and ’40s. So that was the the four features that they had in this MR&T project, which is completely different than the levees only approach that they had prior to that.
Dr. David Biedenharn 46:47
And as I said, the levees were the backbone for the flood control part of the MR&T, and it’s interesting when you look at the levees, a lot of people I’ve had this discussion with a number of people over the years, and I think, where do a lot of people see the Mississippi River? And most of the time they’ve seen it in New Orleans, because a lot of people go to New Orleans, and then they go out and they look at the river, and it’s a mile wide, and they have levees on right there on the top banks, and they’ve got this view of the entire Mississippi River, is this very narrow river with these levees on top banks. But when you look above Baton Rouge, the actual width between the levees, or the levees and the valley wall, we call that the batture. The average width is around seven miles, and in places it’s only a couple of miles. There’s a few places in next down, and in some places it’s almost 15 miles wide.
Dr. David Biedenharn 47:53
So we, with the levee system, we definitely reduce the width of our floodplain, and you know, prior to the levees, there are places the the width could have been 80 miles or more. Well, we don’t have that anymore, so but it’s not like we have a one or two mile levee width running all the way to Cairo. We’ve got quite a bit of batture and floodplain area there, and in fact, I suspect Jack Kilgore may have talked about the importance of the secondary channels in the floodplain, and that is something that we’re looking at a lot more today than we used to, is how can we, can we work in that, that batture area. Since we have a lot of area there, we can still get a lot of benefits from that. So that’s that was the levee system, and that was growing as part of the MR&T, and then we come to the cutoffs.
Dr. David Biedenharn 48:54
As I said, there’d been this no cutoff program, and it lasted up until 1929 and there was the division engineer with the Corps at that time, was a man named General Ferguson, and he was watching this, the river, and just south of Vicksburg, there’s the river, actually, and it was actually occurred in September, kind of in a lower flow time period, but the Mississippi River meandered into a small tributary called the Big Black River, and it captured the Big Black, and it went through it, just went through the Big Black channel and made a meander cutoff through the using the Big Black channel. And so they allowed that to happen. So that was the first natural cutoff since 1880 and they watched it for a couple of years, and they monitored it, and they didn’t see any major problems, didn’t see accelerated erosion or changes in flow lines and water service, and so they made a decision. Okay, well, that we can go ahead and make more cutoffs, and so they, General Ferguson, met with the chief engineers, and they discussed it, and he said, okay, we’re going to use cutoffs to lower the flows, the water surface elevations in the river.
Dr. David Biedenharn 50:24
So before, before I talk about the actual cutoffs, the reason they were considering making these meander cutoffs is by shortening the river, they increase the slope, they lower the flow lines, the water surface elevations. So this was a time when they were building those levees, and so for every foot of flow line lowering they could get with the cutoffs, that was a huge savings in the size and the height of the levees. So they saw that as a really big economic benefit, and which it was, it was also a much shorter distance for the boats to navigate, as it turned out. Below Memphis, it was they reduced the length about 150 miles. So they moved ahead, and I call these a Ferguson cutoffs, and the there were you know below Memphis down to just below Natchez, Mississippi, between about 1933 and 1942, they constructed 15 more cut offs. Actually one of those occurred naturally up around Greenville. And so these these cutoffs, these, these 16 cut offs, including the natural cutoff in 1929, shortened that river about 150 miles, that was about a 30% decrease in length, and that was a tremendous increase in the slope of the river, and as a result of that decreased length. And they saw some immediate drops in water surface elevations, and we have gage readings at a number of places along the river, like at Vicksburg and Memphis, and up around Greenville, Mississippi, and in some places we saw an immediate drop in water surface elevations of 10 to 15 feet.
Dean Klinkenberg 52:32
Wow.
Dr. David Biedenharn 52:32
I mean immediately over a period of year or two, and you never see that dramatic of a change in big river systems, that, and that’s the biggest, most dramatic change of anything I’ve seen on the Mississippi River was the effect in the response of those cutoffs initially, you know, south of Memphis. As a result of that, that shortening of the river, the slopes increased anywhere from 30% to about 90% That’s the water surface slopes. So I’m getting back to my stream power with an increase of 30 to 90% slopes,the stream powers probably increased, you know, accordingly, and with that amount of stream power, the river is, and the sediment supply coming in hasn’t changed. Then the river has got a lot more stream power than it does sediment coming into it, so it’s the river starts thinking about I’ve gotta go find some more sediment to move, and that’s what happens. You now can, it’ll start scouring the bed, scouring the banks, it’ll start trying to remeander, and this is what was happening. And so we had tremendous increases in the sediment transport capacity, and that triggered what we call head cutting, which I mentioned earlier. You get these over steepened slopes, and that starts migrating upstream through time.
Dr. David Biedenharn 54:12
The other side of that is that increased slope and sediment transport is now pulsing accelerated sediment loads downstream, and so it gets to the system effect. We’ve got to think about how all this sediment is being transported and how it relates downstream as well as upstream. And just to complicate this issue a little bit, above Memphis, and this is rarely talked about, but above Memphis, there were a number of chute cutoffs, these smaller chute cutoffs that occurred in the 1930s through the 1950s and there were about 20 of these chute cutoffs that had been documented that shorten the river 20, 25 miles. And so now we had response upstream of Memphis to those shoot cutoffs, which could have been pulsing more sediment downstream into the cutoff, reaches downstream of Memphis, which could actually dampen the head cutting processes, because we’re over supplying sediment from upstream.
Dr. David Biedenharn 55:23
So again, when that’s what I’m just trying to, to emphasize how complex these these channel responses get, and we can’t just focus at one location, we have to look at that whole system. So, so even today, that was, we made those cutoffs 80, 90 years ago. We are still seeing response on the river today, you know, 80 or 90 years later, moving up toward Cairo. So we’re seeing that degradational trend migrate upstream, and that’s one of the areas of research that we have is trying to understand, well, how much more degradation is going to migrate up toward Cairo and beyond, how much it’s going to go up the Ohio, it could go up the Middle Miss, and what happens then. So that’s a, that’s an area of research that we have right now.
Dr. David Biedenharn 56:20
So that was, that’s about as quick as I could talk about the cutoff, I usually talk forever on them, but the, but to add on to the cutoffs, as I mentioned, after the cutoffs were made, the last cutoff, Ferguson cutoff was in 1942, but the river was actually trying to remeander. It was trying to regain that length, and that’s what rivers do. And so there was a period from the 1940s until the Corps got the banks revetted. So, beginning in the 1950s the Corps of Engineers started to revet the banks, putting – when I say revet the banks, we’re talking about putting concrete mattresses now, is what we’re using to revet and protect the meanders to not allow them to erode anymore.
Dr. David Biedenharn 57:12
So, by the 1960s the mid early 1960s the pretty much all the meander bins from Cairo down to the Gulf are locked in place with revetments. So we’ve now taken away that degree of freedom that the river used to have, because you know you mentioned earlier about, you know, changes in how the river responds, and the river is still going to respond to the cutoffs and but now we don’t allow the river to meander, so all the all the adjustments are occurring in the vertical, they can’t go lateral anymore, so it just, the river is still going, going to try to respond, it just going to be a different response than it would have been under a more natural condition.
Dean Klinkenberg 58:04
What does that response look like now then?
Dr. David Biedenharn 58:06
Well, the basically the river is is degrading, have degradation regime say upstream of the Arkansas River, from there up moving toward Cairo, and we see that that degradation is just now getting into the region just south of Cairo, so it’s migrating upstream. We have downstream of the Arkansas River, the river is actually transitions to equilibrium, or maybe slightly aggradational down toward Vicksburg and Natchez. So it’s a, it’s a complex response, but it’s really a typical response to a series of cutoffs. But these, but that response is not just the cutoffs, and that’s where I was going, is that it’s the cutoffs are probably the most dramatic immediate change on the river, increasing that slope that dramatically, but now we’ve got the revetments. We’ve now stopped the river from meandering, and if you recall, I said prior to the 1930s the average annual supply of sediment from the banks between Cairo and Baton Rouge was about 600 million tons per year. Well, now it’s essentially zero. It’s no longer being supplied to the river.
Dr. David Biedenharn 59:30
So, what’s the consequences of that? The, you know, a lot of that sediment is fine sediments, the silts and clays, the wash load. Well, that’s a reduction in that wash load is delivered down to the Gulf. There’s impacts there. There’s a lot of environmental habitat water quality issues with that. There’s also a lot of core sediments, sands, gravels in these banks. That’s no longer being supplied. How is the river responding to that reduced sediment supply coming from the bank. So that can contribute to the channel response as well. So that’s just one issue.
Dr. David Biedenharn 1:00:10
There’s also beginning in the 1960s we began constructing the dike systems on the river. These are transverse riprap structures that extend out into the channel, and these are navigation structures, and they’re designed to cut off the side channels and the secondary channels, and to force more of the water into the main channel to reduce maintenance dredging. And with that, with respect to reducing maintenance dredging, they’ve been a huge success. We’ve really cut dredging down, you know, dramatically, but with like everything else in rivers, you, you always have one effect, but you also have secondary effects, and some of the negative impacts might be that we’re actually closing off some of these side channels, and from a habitat perspective, that’s a negative issue.
Dr. David Biedenharn 1:01:08
So now, and I’m sure Jack Kilgore talked about this, some of the restoration work that’s being done in these side channels in these dike fields, we’re actually going in since the 1990s and we’re making, we’re basically cutting holes in the dikes to allow more water to come through those, those secondary channels from a habitat perspective. So, the Corps is working pretty close with the fish and wildlife to construct these dike notches. But there’s a lot of sediment that’s been trapped in these dike fields, which again we’re removing some sediment from the system.
Dr. David Biedenharn 1:01:47
So all of these features are combining are being integrated to to capture that, or to that cause this channel response that we’re seeing degradation migrating upstream, aggradation and stability downstream. It’s hard to single out, you know, how much relative impact the cutoffs, the revetments, the dikes, the levees. You know, it’s hard to actually quantify, you know, what relative percent each of these is contributing, and I actually try not to, because it just almost gives me a headache trying to think about how to do that, but you know, cumulatively the river is responding to all of this, and and so the present day river is completely different than Charles Dickens’ river, that he saw, and hopefully he would see a better river today. Maybe he would see it even worse. I don’t know.
Dr. David Biedenharn 1:02:47
But we’ve actually transformed a kind of wider bar island dominated slightly aggradational system to a more single channel, more efficient channel that’s designed for flood control navigation. The interesting part of it is even today our channel slopes in the present day river are still anywhere from 10 to 15 to upwards of 60% higher than they were pre 1930s and as a result, we’ve got a lot more stream power in the river. As I mentioned, we have degradation occurring upstream of the Arkansas River, but downstream the river is actually aggradational or in equilibrium, and that comes back to that one of their initial questions you had about the reduction in the sediment loads on the river and it being complex, we talked about the sediment loads being reduced 50 to 85% and that’s primarily that that fine sediment loads that I mentioned that’s measured in suspended sediment calculations, but this is where I’m saying that the bed material sediment loads at core settlement loads are actually higher than they used to be, because our slopes and stream power are so much higher in the river, and we have plenty of sand and gravel in the river for supply, it’s there to be moved, and we have reaches, for instance, here at Vicksburg, the slopes on the river are maybe 15 to 20% higher than they used to be, yet the river is actually slightly aggradational. That means it’s filling up with sediment, so if this, if the slopes were 20%, 15 to 20% higher, yet the sediment loads had reduced 85% we’d be scouring to China here at Vicksburg, we’d be, it would be eroding like crazy.
Dr. David Biedenharn 1:05:00
But it’s not, and that’s where I come from, saying we need to think about the core sediments when we think about these, these bed material or wash load reductions in the sediment loads.
Dean Klinkenberg 1:05:13
So I just want to make sure I’m clear on a couple of terms here again, too, so when you’re talking about the degradation, degradational tendency on the above Memphis, around Memphis, so talking about a deeper channel at that point, essentially.
Dr. David Biedenharn 1:05:29
Yeah, the channel is, it’s very complicated. The degradation we see, you know, you can have the channel bed decreasing, water surfaces are coming down, a lot of it’s just because of the increased slopes that, but yeah, typically you would see the channel enlarging, and we see that when we compare comparative surveys through time, we’ve seen an increase in that area, and a lot of that has to be through the bed deepening, is you know, because the banks are revetted and diked on the other side, but we are seeing an increase in area and channel volume.
Dean Klinkenberg 1:06:11
So the reverse of that, then does that mean there’s a tendency for some parts below there for the channel bed to be rising a little bit?
Dr. David Biedenharn 1:06:21
Yes. The downstream, when we compare the channel surveys, we see a loss of area, cross-sectional area volume in the river. So we’re seeing a loss of volume and area in the river downstream, an increase upstream.
Dean Klinkenberg 1:06:37
And then, so that loss of volume downstream certainly would have some implications for flood control, I would imagine.
Dr. David Biedenharn 1:06:43
Exactly, yes. And that’s where you have to look at that and say, all right, how is this going to impact long-term flood control, levee height, that type of thing. Right now we’re in good shape, but you know what’s it going to be like in 100 years, 200 years.
Dean Klinkenberg 1:06:59
Yeah, interesting. I’ve had, I’ve been lucky enough to walk on some gravel bars on the Lower Mississippi. They’re fascinating places, but so I guess that’s part of the, that is some of the source of those bigger chunks of sediment. Some of the gravel bars, when the river’s higher, it can pick up content from the gravel bars, or you know, maybe rocks that are stuck into the banks and move that further downriver, so because of the increased velocity of the river, now we can carry some of those further down river because of that,
Dr. David Biedenharn 1:07:32
Right, and and then we have to think about, as I mentioned, what is the long term future of the river going to look like with all these changes and complications, and that’s where it gets really interesting. And a number of years ago, the Corps created a program within the MR&T called the Mississippi River Geomorphology and Potamology Program, and that’s what it’s aimed at doing, is trying to understand all these complex processes and interactions that I’ve discussed, and how is that going to affect the future of the river, and when I say the future, I’m thinking 50, 100 years, 200 years. I think we need to be thinking out that far, and it’s we don’t always have tools and ways to be to quantify things 100 or 200 years from now, but we need to start trying to look in that direction, and that’s that’s one of the things we’re trying to do with MRGMP program is to think about what’s the river system going to be 100 years from now, or 200 years, you know.
Dr. David Biedenharn 1:08:47
My, my goal is I want the engineers and scientists 100 or 200 years from now to look back on us and say they may not have really known everything that was going on, and they probably missed and were wrong on a number of things, but at least they established a program and a protocol for moving forward that we’re today in a better position to manage the river, you know, for another 200 years. So that’s that’s my long-term goal.
Dean Klinkenberg 1:09:14
So if we don’t do anything differently for the next couple decades or 50 years or whatever, what would you picture the Mississippi would be like 50 years from now if we didn’t change anything?
Dr. David Biedenharn 1:09:27
Well, in 50 years, I think you know, 50 years for me is a long time, but for the Mississippi is not that long. But I think we would see a continuation of the trends that we’re seeing, a long slow degradational process moving upstream, the degradation moving up toward Cairo. I think will continue. It’s going to be at a slow rate. We might lose another few feet in degradation. We’ll probably see some more aggradation on the downstream, and so we’ll see kind of a continuation of those existing trends, that’s what I would envision.
Dean Klinkenberg 1:10:09
Yeah, I think one of the things that’s really interesting to me, as somebody who doesn’t have to make these decisions, is how difficult it is to develop a plan when you have so many competing, or not necessarily competing, but so many factors that aren’t necessarily complementary. You pull a lever over here, and you get this consequence down here. We can create a river that flows faster and self-scours to some degree, and makes it better for navigation, but then we’ve degraded some of the ecosystems for the life off the main channel, and all of this is relatively expensive as well. Dredging, dredging, the dredging budget is pretty enormous for the Corps, and most of that’s on the Lower Mississippi. Maintaining these structures is not cheap, so like from from your point of view, like what can you tell me, I know there are congressional mandates, but like how in an ideal world, how do we go about balancing all these different factors and making decisions about how to manage this beast of a river?
Dr. David Biedenharn 1:11:21
Wow.
Dean Klinkenberg 1:11:21
Above your pay grade?
Dr. David Biedenharn 1:11:23
Above my pay grade, Dean, but, but that’s a more complication, more complicated question than some of the technical questions. We can technically, you know, if you tell me we, we want flood control and nothing else, we can give you flood control, you know, for whatever event, almost we can make that happen. But that’s probably not going to sit well with a lot of the users and the other people in the valley, which we have to think about, you know, their their viewpoints and impacts to their lives and their livelihoods, and that’s where it gets to be very complicated.
Dr. David Biedenharn 1:12:01
As we mentioned, we can change things to, you know, if it’s just a single goal, single, you know, objective. That’s simple, but it’s no longer single objectives. We’ve got multiple objectives, and most of them are not moving along the same path, and that’s where it gets so complicated, and we almost always run into that. You know, we could, we could restore the entire Mississippi River, we could, we could do away with the revetments and the levees, and let the valley have the floodplain again. That, you know, of course, that would have consequences. We’d probably lose navigation, flood control wouldn’t exist. We’d have us natural, more natural environment out there, but that’s probably not going to happen. And so it’s just, it’s just, it’s hard to satisfy all the different groups, and that’s that’s where I’m glad I’m not the one having to make those decisions, I’m just a technical geek trying to understand the river.
Dean Klinkenberg 1:13:07
Well, as a technical geek who’s been doing this for, for quite a while now, like, what are some of the higher level lessons you’ve learned about the Mississippi from all these years?
Dr. David Biedenharn 1:13:17
The gosh, I think just the connectivity of the system, and understand, and this translates, not just the Mississippi, translates to small streams everywhere, is that we can’t just drop into the river at one location where there’s a problem and put our blinders on and think about fixing that particular problem without thinking about how that reach fits into the system upstream and downstream and how what we might do to change something at that local reach is going to have impacts upstream and downstream. And then how those secondary impacts will have longer term trends as well, so we have this complex response that we see. We see it because we have such a long record on the Mississippi. We can see that complex response, and that’s always been a learning thing for me, and it applies, you know, in streams all over the country and all over the world.
Dean Klinkenberg 1:14:26
Fantastic. So, do you have a favorite spot to go to on the river, like for fishing or partying, or just hanging out?
Dr. David Biedenharn 1:14:37
Not really. We used to have a nice lounge on the Mississippi, called Delta, the Delta Point, I think was the name. It was right there above the bridge at Vicksburg, and had this really nice lounge that you could sit and just look out through these windows, and you can sit there in the evenings and have a have a drink and watch the river flow, and then the casino came in, and then they tore that down, and so my favorite spot is gone. So I don’t have that spot anymore.
Dean Klinkenberg 1:15:08
Bummer.
Dr. David Biedenharn 1:15:09
Yeah, it is.
Dean Klinkenberg 1:15:12
It’s been a while since I’ve been down there. I remember really enjoying St. Catherine Creek National Wildlife Refuge, but that’s a little further south.
Dr. David Biedenharn 1:15:20
Yeah.
Dean Klinkenberg 1:15:21
But I thought that was a beautiful area.
Dr. David Biedenharn 1:15:25
Yeah.
Dean Klinkenberg 1:15:26
Well, David, is there anything else you feel like we didn’t cover that you want to add before we wrap this up?
Dr. David Biedenharn 1:15:34
Gosh, I’m trying to remember what I, what I said in the last hour so.
Dean Klinkenberg 1:15:39
We just got a master class, I think, so.
Dr. David Biedenharn 1:15:41
I don’t know, we got something, but hope I didn’t ramble and babble too much, so.
Dean Klinkenberg 1:15:49
No, that was fantastic, and you explained it very clearly, so I deeply appreciate your time and sharing your expertise with us, and thank you again, like hopefully this, you know, maybe it’ll raise a few questions, maybe people will reach out and have some questions. Is there a place where people can follow the work that you’re doing?
Dr. David Biedenharn 1:16:11
There is. If they go, I don’t have the link to tell you right now, but if you go on to the Corps of Engineers Mississippi Valley Division Office, there’s a Mississippi River Geomorphology and Potamology site there, and there’s a lot of information there about some of the studies that have that have gone on. That’s one place, there’s also the here at ERDC, we have a library, you can go to the ERDC library, and if you have particular authors or people or topics you’re interested in, you might can research and find some publications there.
Dean Klinkenberg 1:16:58
All right, we will search those out, and I can put links to those in the show notes for folks. So, well, thank you very much, David. Grateful, deeply appreciate your time today.
Dr. David Biedenharn 1:17:10
All right, if you ever get to Vicksburg, come see us.
Dean Klinkenberg 1:17:13
Thanks for listening. If you enjoyed this episode, subscribe to the series on your favorite podcast app, so you don’t miss out on future episodes. I offer the podcast for free, but when you support the show with a few bucks through Patreon you help keep the program going. Just go to patreon.com/deanklinkenberg. If you want to know more about the Mississippi River, check out my books. I write the Mississippi Valley Traveler guidebooks for people who want to get to know the Mississippi better. I also write the Frank Dodge Mystery Series that’s set in places along the river. Find them wherever books are sold. The Mississippi Valley Traveler podcast is written and produced by me, Dean Klinkenberg. Original music by Noah Fence. See you next time.
