The Decades-Long Effort to Tame the Wild Mississippi River: How Engineers Reshaped America's Greatest River

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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.

Episode Transcript

Dr. David Biedenharn (00:00):
And so when we look at the river pre
1930s it was a completelydifferent river regime than what
we have today, it was, it wasmore islands, bars dominated,
dominated system, log jams, itwas it was it was a mess, it was

(00:22):
wide, shallow, more shallow, andmaybe slightly aggradtional,
maybe slightly building up. Sothat was the river that we had
in the 17, 1800s as the nationwas 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 thepeople and places along
America's greatest river, theMississippi, since 2007. Join me
as I go deep into the charactersand places along the river, and
occasionally wander into otherstories from the Midwest and

(01:18):
other rivers. Read the episodeshow notes and get more
information on the Mississippiat
MississippiValleyTraveler.com.
Let's get going.
Welcome to episode 78 of theMississippi Valley Traveler
podcast. Well, as this episodegoes out, we are in the second

(01:39):
week of River Days of Action.
I'm hoping you're all finding agood way to celebrate the river,
maybe give a little bit back tothe river, but certainly spread
the word about the joys ofspending time along the
Mississippi River, and why it'ssuch a special place. If you're
looking for ideas on things youcan do during the remaining days
of River Days of Action, head toMississippiRiver.org and you'll

(02:02):
find a complete schedule there.
So, in this episode, we aregoing to take a deep dive into
the dynamics of the lowerMississippi River with Dr. David
Biedenharn, who's a professionalengineer and has spent over 45
years of his career trying tounderstand the dynamics of this

(02:22):
mighty, mighty river, the LowerMississippi. He's a Vicksburg
native, and we talked brieflyabout his history growing up
with the river and what it meantto him as growing up. Then we
get into some of the basics ofhow river engineers approach
trying to understand the flowand dynamics of this mighty
river. We talk about thehistoric flow characteristics of

(02:43):
the Mississippi, for example,and how we've changed it through
the engineering structures. Theriver's sort of fundamental push
toward equilibrium, and how thatplays out. We go into some depth
talking about meanders and howthey develop and what they can
tell us about the river state.
We talk about the concept ofstream power, what that means in
engineering terms, andengineers, and we talk some
about the river's sediment loadand factors that influence the

(03:08):
size and volume of sedimentcarried by the river, and why
that matters.
Then we'll spend a little bit oftime talking about the history
of flood control in the LowerMississippi, and how those
efforts have altered the river,and how the river has often
responded to our attempts toconfine it into a narrower

(03:28):
channel by finding other ways tomeet its needs for equilibrium.
At least, as I understand it,.
This is not my specialty, but Ireally enjoyed talking with
David about this stuff. I have afeeling we could go on for a
long time into the depths ofthis, but I think this is a
really good generalintroduction, and he does a
great job explaining theseconcepts and explaining them in
a way that I think, if I canunderstand it, I assume just

(03:50):
about anybody could.
As usual, thanks to those of youwho show me some love through
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(04:12):
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and from there you'll find outhow you can buy me a coffee. And
at that same place,MississippiValleyTraveler.com/podcast

(04:32):
you will get access to allprevious 77 episodes. You can
pick and choose an episode tolisten to, or you can just go
crazy and binge them all if youwish.
And let me just remind folks, asthis goes out, that the
Kickstarter campaign for my newbook, a travel memoir called

'Better Safe Than Sorry (04:50):
Slow Boats, Chicken Busses, and the
Radical Choice to Trust theWorld,' the Kickstarter campaign
for that is just about to golive. You can currently sign up
for a pre-launch page, whereyou'll be notified as soon as
the campaign goes live, or youcan wait till June 15 when it
goes live, and then you can gothere and buy yourself a copy of

(05:13):
the book, if you wish. If you'reinterested in more, go to
DeanKlinkenberg.com/BetterSafeThanSorry.
All right, let's get on with theinterview. Dr. David Biedenharn

(05:39):
is a professional engineer withover 45 years of experience in
hydraulics, river engineering,sediment transport, and fluvial
geomorphology with the US ArmyCorps of Engineers, Vicksburg
District, specifically theEngineer Research Development
Center, or ERDC, at theWaterways Experiment Station in
the Lower Mississippi ValleyDivision Office, as well as with

(06:00):
the Biedenharn Group. He'spresently a research hydraulic
engineer with the RiverEngineering Branch at ERDC. His
work experience includes thehydraulic design of flood
control and navigation channels,levees, geomorphic assessments,
bank stabilization measures, andgrade control structures,
channel restoration projects,and regional sediment

(06:21):
management, and we will get intosome of these topics
specifically in just a minute.
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 gotinterested 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. Neverthought I would end up staying
here for most of my life, but Ijoined the Air Force in 1969 and
when I got out in 1973 the Corpsof Engineers Vicksburg District
was hiring at that time, so theyhired me as a hydrologic

(07:00):
technician, and I was actuallydoing sampling on the
Mississippi River, samplingwater and sediment, and also a
lot of the smaller tributaries.
So that was my first real, Iguess, introduction to the
Mississippi River. Other thanwhen I was in high school, it
was a place to go and boat anddrink beer and have a good time.

(07:21):
But, so that was my first stepinto the river and got me
interested in it, and then Iwent back to school and I got my
engineering degree, civilengineering, and I came back to
work for the Vicksburg Districtand I was working in what was
known at that time as thepotamology section and I imagine
there'll be a lot of peoplewondering 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 atthat time, in the late '70s, I
was working for a man namedBrian Winkley, who was my
mentor. He's the one that reallygot me interested and excited
about rivers, and basically atthat time we were trying to

(08:09):
understand how the MississippiRiver was responding to
everything man and nature hadthrown at it over the last
several 100 years, and so that'show I really got started looking
at rivers, and then I branchedout into doing a lot of small
stream work as well, and thenafter about four or five years

(08:33):
they changed the name ofpotamology, because nobody knew
what it was, and we startedcalling it river engineering, so
now it's the river engineeringgroups, and I'm still working in
river engineering today, sothat's really how I got
interested in it, and, and it's,it's been kind of a passion of
mine. I actually retired fromthe Corps almost 20 years ago,

(08:58):
and I ran my own engineeringcompany for about nine years,
and then one day I realized thatI had this real jerk for a boss,
and that was me. My wife said,"You need to do something
different," and I had theopportunity to come back to work
at ERDC here in Vicksburg, andI'm getting to work with all the

(09:20):
young engineers and scientistshere, and I've been doing that
for the past six years, andthis, 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 somework on the Mississippi, and
then had a hard time steppingaway 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 lotof changes to it, and then how
the engineering has affectedthat river, and it seems like
that's a bit, as you justhinted, is sort of a big part of
the work that you're doing. Whydon't you start by painting us a

(10:02):
picture of the river a few 100years ago?

Dr. David Biedenharn (10:06):
Okay.
Well, if we look back, and I'lltalk about the. I'm really going
to be focusing on the LowerMississippi River, which is
really starts around Cairo,Illinois, where the junction of
the Ohio and the Middle Misscome together, and so that's the
area the river I'll be focusingon today, and really from Cairo

(10:26):
down to about Old River, andthat's where the Atchafalaya,
the Mississippi diverts out intothe Atchafalaya, and then flows
on down through Baton Rouge inNew Orleans, and there's a,
that's a whole nother riverdownstream of Old River, and
maybe we'll leave that foranother day, and maybe another

(10:48):
person to discuss that. Butthat's the reach of the river
I'm going to be talking abouttoday.
And if we look back in time overthe last 6, 7, 800 years from
Cairo to the Gulf, theMississippi River had an
approximate length of around1100 miles, and it's interesting

(11:09):
when you look at those changesevery, every century they had,
they had mapping that they couldestimate the length, and it
would, it would gain in lengththrough some periods, they would
lose length in others, but it,it hovered around 1100 miles. It
might, it might increase 50 to75 miles in one one century,

(11:32):
then decrease again, but itmaintained that length, and it
did that by meandering, andthat's how rivers actually
maintain their health, but whenI say meandering, I'm talking
about, you know, the outer banksof the river are eroding, and
the river is migratinglaterally, point bars are
building, the floodplain isgetting sediment in there, and

(11:54):
what happens through time asthat river meanders is gaining
length, it's getting longer. Butthen they'll make, the river
will make natural cut offs, andwe'll call these neck cut offs,
and these - this is where theriver cuts across the neck of
the of the bend, and it leavesthese old large oxbow lakes that

(12:16):
you see in the floodplain, sothe river may be shortening in
one area and lengthening inanother, but overall it was
trying to maintain the samelength over that time period.

Dean Klinkenberg (12:29):
Just for clarity, to when we say 1100
miles in length, we're talkingabout 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 keepthat same length, and if you
think about it, it has the sameelevation drop from Cairo to the
Gulf, so it's trying to maintainits slope, and that's where we
get into this whole question ofsediment and the movement of

(12:57):
sediment through streams that isa function of the the energy in
the river, which is what we callstream power, which comes from
just the how much water ismoving in the channel, how many,
how many million cubic feet persecond is passing Vicksburg, you
know, per second. And thenwhat's the slope of the river,

(13:20):
so the product of the discharge,the water, and the slope of the
river is what we call streampower. That's where the energy
of the river, where it gets itsenergy to do work, and by do
work, it can cave the banks, itcan scour the bed, it can move
sediment. So that's when wethink about sediment and all the

(13:41):
things we'll talk about on theMississippi over the next couple
100 years, it's going to berelated to how that stream power
is changing and the movement ofsediment. So, the higher the
stream power, the more slope youhave, the higher the discharge,
the more sediment that it canmove. We can get, we could drill
into the details of that, but Idon't want to bore people too

(14:02):
bad right off the bat, butthat's the, but that is the way
getting back to this link,that's the way the river
maintains its, its health andits stability. If it, if it has
just the stream power to movethe sediment that's coming into
the river, then it's not goingto be filling up with sediment,
and we call that aggradation, orit's not going to be searching

(14:26):
for more sediment and scouringthe bed and the banks and
enlarging, that's calleddegradation. And so it's sort of
in a balance, it's balanced thatstream 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 thisfactor is the nature of the soil
that the river is passingthrough, like if the river is
passing through rock, obviouslythat's different than dirt, but
can you describe sort of whatthe soil context is like for

(15:03):
that section of the Mississippi?

Dr. David Biedenharn (15:05):
Right, in fact, that's exactly the next
part of this relationship. Thisbalance is not only how much
sediment is moving, the load,and we usually call that the
sediment load, and that might bemeasured in tons per day of
sediment, but the other part ofthat is, what size sediment is
it? Is it moving sands, gravel?
It's like the Mississippi Riverthat we're talking about. The

(15:30):
dominant dead material that wehave out in the stream is going
to be fine, medium core sandsand gravels. If we go up into
the mountainous streams, it maybe moving gravel, cobbles,
boulders, so all streams aredifferent, but they're all
trying to, they're all relatedto this stream power and

(15:54):
sediment balance, but thesediment size plays a big part
of that, for sure.

Dean Klinkenberg (16:02):
And historically speaking, Where did
most of that sediment in theMississippi come from?

Dr. David Biedenharn (16:11):
From the watershed all the way to the
mountains. I mean, theMississippi River drains, I
think, 41% of the United States.
So all that sediment, you know,from the watershed comes in,
coming from the watersheditself, from the tributaries,
and then it's in the floodplainitself, and the river is
meandering through thatfloodplain over 1000s of years,

(16:32):
you know, reconnecting witholder sediments and moving that
through, so it's a complex mixfrom a lot of different sources,
but to understand how riversbehave, we have to think about
those sources. Where is thatsediment coming from? How is it
moving through the channelitself to to where it ultimately
drops out in some place that wemight call a sink area. It could

(16:57):
be the Gulf, or it could be in areservoir 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 youballpark like about what percent
of the sediment passing by thatspot a couple 100 years ago
might have come from theMissouri River and the Great
Plains versus how much wouldhave 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, weteach a lot of classes in river
engineering, and, and oftentimesthe answer is, and this
irritates a lot of engineers,but the answer is, it depends.

(17:51):
We found that it's often thebest answer. It could be a lot
of the, and this, this gets intothe, the type of sediment load,
and without getting into toomuch detail, there's sediment
that we call wash load, and thiswould be the very fine

(18:11):
sediments. If we think about theMississippi River, say at
Memphis, the wash load would bethose fine sediments, silts,
clays, very fine sands that arepretty much in suspension all
the time that don't reallysettle out in the channel itself
to any appreciable amount. Theymay deposit when it gets into

(18:33):
the overbank flood plain or intosome side channels, but for the
most part that sediment is ispurely a function of the supply,
what's coming in from upstream,and in that case, some of that
sediment could, could be comingfrom the Missouri River, because
it moves through the system veryquickly.
There's also what we call bedmaterial sediment load, and

(18:56):
that's the sediment load that'smade up of the sediments that
make up the bed of the river,and that would be the coarser
sediments in Memphis, that wouldbe fine, medium course sands,
maybe some gravels, and it'sthat bed material load that
moves much differently than thewash load, because it's moving

(19:17):
as a result of the energy of thestream, it moves slower and that
is the load that we focus onwhen we start thinking about
channel response to somealteration we do in a river
system. If we make a change in ariver system, we're thinking
about how that affects that thatcoarser sediment, whereas the

(19:40):
wash load is really not, notfigured into that calculation,
to is it's only to a limiteddegree. So there, and it's, it's
not often, it's not always easyto differentiate sometimes for
what's wash load and what's bedmaterial, but in general at the

(20:00):
100,000 foot view, you could saythe silts and clays and very
fine sands just move through thesystem until they hit down below
New Orleans somewhere, then theydrop out. And whereas the bed
material is that coarsersediment, so that bed material
sediments at Memphis 200 yearsago was probably sourced from

(20:21):
just upstream coming in thechannel itself, because that
sediment is not moving as far oras fast, and again I hesitate to
get into too much more detailsabout bed material and wash
load, but it is a criticalcomponent of understanding
sediment loads on the river,because they're completely

(20:43):
different loads, and the riversystem reacts differently to
both of those.

Dean Klinkenberg (20:48):
Right. And I guess, like, you know, flood
events, you know, flood pulseswould have a big impact too on
what sediments are being carriedand where they're dropped. And I
guess with that earlierquestion, kind of what I was
thinking too, is I rememberseeing charts that kind of
compare what we believe thehistoric sediment load of the
Mississippi was before theMissouri River was dammed up the

(21:12):
way it is today, and what thatsediment load looks like today,
and it sort of implied that thebulk of the sediment was coming
down the Missouri River. Itseems like you're saying maybe
there's some truth to that, butit'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 verywidespread figure. I think I
know the figure you're, you'retalking about. I think that
it's, I think they call it aSecchi diagram or something, but
it's kind of like Napoleon'smarch from Russia, how they, you

(21:51):
know, it got smaller and smalleras he got toward, you know,
Paris, whereby all the soldiersdying off. Well, they show the
same thing with the Mississippiwith that, that chart, the width
of the of the chart, you know,kind of describes the amount of
loads, and and these are theseare estimates that have been
made based on measured suspendedsediment data in the river, and

(22:13):
they have a lot of people havedocumented this and shown that
the sediment loads on theMississippi River have reduced
anywhere from 50 to 85% todayversus what they were maybe 60,
70 years ago.

(22:33):
And when you look at that data,that is correct, that is, that's
what the data shows. Where itget and so that suggests that
there's a significant decreasedload sediment load on the
Mississippi River today, andwhile that is true, we have to
think about what sediments we'retalking about there, and that's

(22:57):
rarely discussed, and this isthese estimates all come from
measured suspended sedimentdata, which is, which is really
good data. We use it all thetime on rivers all over the
world, but it's, it has alimitation that most of it
typically they're capturing thatfiner sediment load, the silts,

(23:19):
the clays, maybe the very finesands, and it's not a very good,
in my view, a very goodrepresentation of the bed
material load on the river, andwe can, I can talk about this
later, but in my view, as aresult of a lot of things that
have happened to the river,which we, we can discuss in a

(23:41):
few minutes, that the streampower on the Mississippi River
today is much, much higher thanit was 50, 60, 70 years ago, and
therefore I believe that theactual bed material loads, that
coarser sediment is actuallythere's higher loads of that

(24:03):
today than there were 60 or 70years ago. But maybe we'll,
we'll hold off some of thatdiscussion to later after we
talked about why I believe someof 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 ofwalk through, take us from where
the river was maybe a couple of100 years ago to where it is
today, because there's a lot ofthings that have happened to it,
and I think if we're going tounderstand the Mississippi
River, we need to understandwhere it was and how it got to

(24:37):
where it is today. And so if welook back, some of the I'm
really going to start, maybe inthe late 1700s, that's 1765 is
one of our first mapping of theMississippi River, and we have
others in 1820s, 1890s, and soforth, and we can compare the

(25:01):
river through those time periodsto see how it's changed, but I
think about this, this, theearly 1800s that's about the
time that our nation wasexpanding in into the to the
western part of the nation, andin a way we kind of picked a bad
time to move into this area,because the Mississippi River in

(25:22):
1811, 1812 we had what is knownas the - I'm sure you're aware
of this - the New Madridearthquakes that really just
shook the heck out of theMississippi River. Supposedly it
rung the church bells in Boston.
I'm not sure about that, but wehad anecdotal information that

(25:43):
you know, islands and bars justcompletely disappeared. It just
shook the heck out of the systemas far down as Vicksburg. The
river flowed backwards andcreated lakes, introduced a heck
of a lot of sediment into theriver system.
So, right off the bat, we've gotMother Nature working against us
a little bit, and then we thinkabout all the boats that were

(26:05):
navigating the river back in1800s, the steamboats. Most of
these were wood burningsteamboats, and for a lot of
reasons, because there wasplenty of locations to get that
fuel all along the river, and soyou can look at a lot of the old
maps from the 1800s and you'llsee they'll mention these wood

(26:27):
yards that grew up all up anddown the river, and these, these
folks would actually go clearall the trees off the banks, put
them on barges, float down intothe river, and sell it to some
captain going up or down theriver, and they pull back in,
cut some more trees, and so theywere completely denuding the

(26:48):
banks of the river at that time,which were were taking away some
of the vegetation, which kind ofhelps with some of that bank
erosion, and at the same timesome of the banks were being
cleared for agriculture. Ifpeople 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,

(27:10):
and so the river was extremelydynamic at that time, and some
of our studies here in the lastseveral years, we looked at some
of those historical surveys fromthe 1700s, 18 to 1930s and only
on up to present day, and one ofthe things we found, and when we

(27:30):
looked at the meander migration,how, how fast, and how what kind
of rate of erosion these meanderbins had, they could range
anywhere from 30 an average of30 feet per year to close to 100
feet per year, and that's justan average.

Dean Klinkenberg (27:48):
Wow.

Dr. David Biedenharn (27:49):
And as a result, we made some
calculations of how much, howwhat the total volume of
sediment being eroded from thestream banks between Cairo and
Baton Rouge was in that pre1930s period, and it was about
600 million tons per year. And Ithink 600 million tons, I can't

(28:14):
even get my head around what,what that number means, but if
we look at the total measuredsuspended loads on the
Mississippi River today, say,you know, at Vicksburg or
somewhere, is probably 120 to150 million tons per year. So
this was one heck of a lot ofsediment that was being

(28:36):
generated from those that bankcaving, and where does that
sediment go, and that gets intothat sources the pathways and
sinks again. A lot of that, alot of that sediment coming out
of the banks would have beenfine sediments, silts and clays,
and that could have been justpushed into the river and

(28:56):
transported quickly downstreamto the Gulf, or somewhere, you
know, close to that. But a lotof that was coarser sediments,
the bed material size sedimentsthat would be deposited on the
bars, and so when we look at theriver pre 1930s it was a
completely different riverregime than what we have today.

(29:17):
It was, it was more islands,bars dominated, dominated system
log jams. It was, it was, it wasa mess. It was wide, shall more
shallow, and maybe slightlyaggradational, maybe slightly
building up. So that was theriver that we had in the 17,

(29:40):
1800s as the nation was growingand trying to use this river for
navigation. I often like to readCharles Dickens' quote. I don't
know if you've read that he madea trip down the Mississippi
River in 1840s. I don't know,Dean, if you had a chance to

(30:00):
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 anexcerpt or two from it. And this
was just his impressions, andthey 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 descriptionof what the Mississippi River
was like back in that time. Sothat's why I like to read it. I
wish I could do it with a goodEnglish accent, then my IQ might
go up about 10 or 20 points, butbut he says, "at the junction of
the two rivers," and he'stalking about the Ohio and the

(30:38):
Middle Miss, there around Cairo,"lies a breeding place of fever,
ague, and death, a dismalswamp," says, "a place without
one single quality in earth orair or water to commend it, such
as this dismal Cairo." He saysit's "an enormous ditch,
sometimes two or three mileswide, running liquid mud six

(31:00):
miles an hour is strong andfrothy current choked and
obstructed everywhere by hugelogs and whole forest trees now
twining themselves together atgreat rafts. For two days we
toiled up this foul streamstriking constantly against the
floating timber or stopping toavoid those more dangerous

(31:23):
obstacles, the snags or sawyers,which are the hidden trunks of
trees that have their rootsbelow the tide." Well,
obviously, there's a littlesarcasm in Dickens' view of the
river, but I like that quote, inthat it really describes what
our rivers looked like backthen. And it was, it was wide,

(31:45):
more shallow, bars, islands,just debris, log jams all
through it, and that's the riverwe 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'realmost arguing that this was
kind of an exceptional period inthe river's history, that
because of combination offactors, including the New
Madrid earthquakes, thedeforestation along the
riverbanks, that we kind ofcreated or had created this

(32:23):
river that was particularlydifficult to navigate in that
period of time, and maybe 100years before that, maybe the
river characteristics might havebeen a little bit different, or
maybe not quite as unfriendly toboats.

Dr. David Biedenharn (32:36):
Yeah, it's hard to say exactly, but you
raise a really good point that'sbeen discussed a lot, that when
we compare, for instance,sediment loads again, we're
saying sediment loads today are80% less than what they were 100
years ago. Well, it could havebeen that the sediment loads 100
or 200 years ago wereaccelerated, they were higher

(32:57):
than normal, can't say that, youknow, with any certainty, but
obviously there were otherthings going on in this period,
and I think it was obviouslyprior to that the river was very
dynamic, obviously, but thiscould have been a been the
stability or instability couldhave been exacerbated by some of

(33:19):
these, the deforestation andsome of the natural, the New
Madrid earthquake, and some ofthese things.
So, I like saying it was a toughtime to be thinking about trying
to navigate the river. If youread Mark Twain, you really
understand that. And, but what.
So, the Corps of Engineers wasinvolved with this, and then in

(33:40):
1879 they formed the MississippiRiver Commission, which was a
commission. It was actuallylocated here in Vicksburg, and
the it was the MRC was given thecharge of managing the
Mississippi River fornavigation. We're really only

(34:01):
talking about navigation at thattime. Flood control was not
really part of the authorizationhere.
So, when the Mississippi RiverCommission started looking at
how are we going to maintainthis river for navigation, they
considered a lot of differentapproaches, and they looked at

(34:26):
building levees, and the ideathere was they could build
levees and restrict the riverand not allow it to break out or
crevasse down into some of theseoutlets, they would keep all the
energy in the channel systemitself, and not let the water
escape through these, thesecrevasses. Then they could keep

(34:47):
the channel self-scouring, waswas the idea there. That was one
of the alternatives. They alsoconsidered it maybe going up and
building reservoirs, dams toreduce some of the flow. They
looked at some outlets, theythought about, you know, maybe
providing some outlets indifferent places, and probably
the most controversialdiscussion was the making

(35:09):
meander cutoffs, and so, as Iunderstand it, there was some
pretty heated discussions andarguments about what the
approach was, and in the end,the MRC settled on what is known
as the "levees only" policy, andmaybe I'll discuss this in some

(35:29):
previous podcasts, I'm not sure.
And basically, as I said, theidea there was keeping more of
the energy within the levees tokeep the channel self scouring,
so they wouldn't have to dredgeas much to keep the channel open
for navigation. And that was inthe 1880s that they established

(35:51):
that.
A lesser known part of thatpolicy, well, they actually had
a "no cutoffs" policy and Ithink that grew out of this
debate about having cutoffs onthe river, and cutoffs are a

(36:12):
lightning rod for debate amongriver engineers, because there's
pros and cons to makingartificial or man-made cutoffs.
I'm not talking about naturalcutoffs. And the advantages are
you can actually increase theslope, and you can have more of
a getting the water out faster,you can scour the channel, and

(36:36):
the negative aspects is youincrease the slope, and you have
scouring, and it also can createwhat we call head cutting, and
head cutting is where the oversteep and degradational zone in
a river migrates upstreamthrough time, and as it's doing
that, it's pulsing more and moresediments, bed material

(36:58):
sediments downstream, whichaggravates the aggradational
problems, so there was a lot ofthat debate, and I think because
of that they decided we're noteven gonna allow the river to
make its own natural cutoffs,and so from 1880 to 1929 the

(37:19):
Corps did not allow theMississippi River to make any
natural meander cutoffs. Theseneck 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 havetoday 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, andthey would come in, and they
would build these, these willowmats, woven willow mats that

(37:54):
they would weave together 1000sand 1000s of willow trees into a
mattress along the bank, andthen they would sink it with
stone to sink it down onto thestream bank. And that was
actually a very successfultechnique, and these mattresses,

(38:15):
if you keep, you keep woodsubmerged and wet, it can last
for an awfully long time, and sothat's the way they did it, and
so between I think 1880 and 1929there were no neck cutoffs,
natural cutoffs on theMississippi.

(38:36):
Interesting enough, and this hasalways fascinated me, so you
think about it, we didn't allowthe river to shorten itself, and
it was continuing to erode andmeander in other places, so you
would think that the river wouldbe much longer in 1929 than it
was in 1880 when we stopped it,and the thing is, it wasn't. And

(38:59):
the reason is there's anothertype of cutoff we call a chute
cutoff, which is where the riverjust widens out a bit, and the
channel will will make ashortcut across the point bar,
and that's called a chutecutoff. And whereas a neck
cutoff might, a single neckcutoff might remove 20 miles

(39:20):
from the stream, a chute cutoffmight only remove a mile,
shorten the river a mile, maybetwo miles, three miles. But what
happened, they didn't stop thechute cutoffs, and the the
number of chute cutoffs went updramatically during that time
period, and I always kind ofthink of that as Mother Nature

(39:43):
saying, "all right, guys, I'vegot a bigger dredge than you do,
you're trying not to let me makethese cutoffs, I'm going to go
ahead and shorten it up becauseI need to keep my slope, you
know, in the right, you know,regime," and so it actually
increased the number of chutecutoffs by almost a factor of
three, and that by 1929 theriver wasn't much longer than it

(40:08):
had been in 1880. So I guessit'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 abalance in place in this whole
system, and maybe you'll touchon this a little bit later too,
but like when you startmonkeying around a little bit
with the dynamics in this onearea, then there are
reverberations throughout theentire 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? LikeHenry 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 naturalcutoffs every century. Just
that's just an average, sothat's that's kind of the
natural sequence or frequency ofcutoffs that the river had, and

(41:21):
so these were always occurring,and then, like you say, Captain
Shreve and others made somecutoffs down Roanoke River and
other places, so there were someof those there, so there were
some artificial cutoffs beforethese, these in 1930s which we
really haven't talked about toomuch yet, so.

Dean Klinkenberg (41:42):
Hey, Dean Klinkenberg here. Interrupting
myself. Just wanted to remindyou that if you'd like to know
more about the MississippiRiver, check out my books. I
write the Mississippi ValleyTraveler guidebooks for people
who want to get to know theMississippi better. I also wrote
"The Wild Mississippi," a guidethat goes deep into the complex

(42:03):
ecosystem supported by theMississippi, the plant and
animal life that depends onthem, and where you can go to
experience it all. If you likefiction, check out my Frank
Dodge mystery series. Each bookis set in places along the
Mississippi River. My newestbook is a travel memoir called

"Better Safe Than Sorry (42:20):
Slow Boats, Chicken Busses, and the
Radical Choice to Trust theWorld." The book explores a

simple question (42:27):
What happens when you stop asking what if
something goes wrong and startasking what if everything goes
right? Find out more atdeanklinkenberg.com/bettersafethansorry.
So the in that debate, thenaround 1880 when the Corps is
deciding not to do any moreartificial cutoffs, were those

(42:50):
earlier cutoffs in their minds,was that where they was
something about those cutoffsprescient for them that they
caused them worry about doingmore?

Dr. David Biedenharn (42:59):
You know, there was there was a quite a
bit of literature all around theworld, European experiences with
cutoffs, and I'm, and I guess Ishould be clear, I'm talking
about their concern at thattime, their debate was about
making artificial or man-madecutoffs. And so there had been

(43:19):
quite a bit of knowledge aboutthe impacts of cutoffs, and
that's what they were debating.
But I believe what happened withtheir "no cutoff" policy, they,
they took that even further andsaid we're not only going to not
going to make artificialcutoffs, 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 nocutoffs, and then everything
really was moving along prettywell until the 1927 flood. And I
know that you probably haddiscussions of the 1927 flood.
It was one of the worst naturaldisasters in our country's

(44:13):
history. Hundreds of thousandsof people were displaced,
several hundred people, probablymore than that, were were
killed. It was a, it was just amajor event, and, but what it
did, it kind of galvanized thecountry, and really started us
thinking more about thesystematic approaches for flood

(44:34):
control, as well as navigation.
We started moving into floodcontrol a little bit before
that, but as a result of the1927 flood, there was the 1928
Flood Control Act, and in thatact they created the Mississippi
River and Tributaries Project.
And that is the authority andthe projects, the project that

(44:58):
we're actually working under onthe Lower Mississippi River
today. So that's the genesis ofthat project.
When they started thinking aboutthis, what would the MR&T
project entail, again they hadto start thinking about all
these other options, and becausenow they're talking about flood

(45:20):
control and as well asnavigation, and so they looked
at a lot of different features,and they started thinking about
more of a comprehensiveapproach. And so they
incorporated four majorcomponents to the MR&T project.
They included levees, so theyrecognized levees were

(45:42):
definitely kind of the thebackbone from a flood control
perspective, they were going tohave to have levees. Then they
also included some floodways,allow some some water to go out
at certain locations, and theyalso gave authority to work up
into the tributaries, which was,which was a first for the river,

(46:04):
too. So now they could go up andwork into the tributaries
themselves. And then the bigchange was the channel
improvement features, and thechannel improvement features
included all the work in thechannel itself, and that that
included revetments. We're goingto talk about that in a minute,
the dyke systems, localmaintenance, dredging, and the

(46:29):
cut off program of the 1930s and'40s. So that was the the four
features that they had in thisMR&T project, which is
completely different than thelevees only approach that they
had prior to that.
And as I said, the levees werethe backbone for the flood

(46:52):
control part of the MR&T, andit's interesting when you look
at the levees, a lot of peopleI've had this discussion with a
number of people over the years,and I think, where do a lot of
people see the MississippiRiver? And most of the time
they've seen it in New Orleans,because a lot of people go to

(47:14):
New Orleans, and then they goout and they look at the river,
and it's a mile wide, and theyhave levees on right there on
the top banks, and they've gotthis view of the entire
Mississippi River, is this verynarrow river with these levees
on top banks. But when you lookabove Baton Rouge, the actual
width between the levees, or thelevees and the valley wall, we

(47:40):
call that the batture. Theaverage width is around seven
miles, and in places it's only acouple of miles. There's a few
places in next down, and in someplaces it's almost 15 miles
wide.
So we, with the levee system, wedefinitely reduce the width of
our floodplain, and you know,prior to the levees, there are

(48:02):
places the the width could havebeen 80 miles or more. Well, we
don't have that anymore, so butit's not like we have a one or
two mile levee width running allthe way to Cairo. We've got
quite a bit of batture andfloodplain area there, and in

(48:22):
fact, I suspect Jack Kilgore mayhave talked about the importance
of the secondary channels in thefloodplain, and that is
something that we're looking ata lot more today than we used
to, is how can we, can we workin that, that batture area.
Since we have a lot of areathere, we can still get a lot of
benefits from that. So that'sthat was the levee system, and

(48:45):
that was growing as part of theMR&T, and then we come to the
cutoffs.
As I said, there'd been this nocutoff program, and it lasted up
until 1929 and there was thedivision engineer with the Corps

(49:05):
at that time, was a man namedGeneral Ferguson, and he was
watching this, the river, andjust south of Vicksburg, there's
the river, actually, and it wasactually occurred in September,
kind of in a lower flow timeperiod, but the Mississippi
River meandered into a smalltributary called the Big Black

(49:30):
River, and it captured the BigBlack, and it went through it,
just went through the Big Blackchannel and made a meander
cutoff through the using the BigBlack channel. And so they
allowed that to happen. So thatwas the first natural cutoff
since 1880 and they watched itfor a couple of years, and they

(49:52):
monitored it, and they didn'tsee any major problems, didn't
see accelerated erosion orchanges in flow lines and water
service, and so they made adecision. Okay, well, that we
can go ahead and make morecutoffs, and so they, General
Ferguson, met with the chiefengineers, and they discussed

(50:15):
it, and he said, okay, we'regoing to use cutoffs to lower
the flows, the water surfaceelevations in the river.
So before, before I talk aboutthe actual cutoffs, the reason
they were considering makingthese meander cutoffs is by
shortening the river, theyincrease the slope, they lower

(50:35):
the flow lines, the watersurface elevations. So this was
a time when they were buildingthose levees, and so for every
foot of flow line lowering theycould get with the cutoffs, that
was a huge savings in the sizeand the height of the levees. So
they saw that as a really bigeconomic benefit, and which it

(50:59):
was, it was also a much shorterdistance for the boats to
navigate, as it turned out.
Below Memphis, it was theyreduced the length about 150
miles. So they moved ahead, andI call these a Ferguson cutoffs,
and the there were you knowbelow Memphis down to just below

(51:22):
Natchez, Mississippi, betweenabout 1933 and 1942, they
constructed 15 more cut offs.
Actually one of those occurrednaturally up around Greenville.
And so these these cutoffs,these, these 16 cut offs,

(51:44):
including the natural cutoff in1929, shortened that river about
150 miles, that was about a 30%decrease in length, and that was
a tremendous increase in theslope of the river, and as a
result of that decreased length.
And they saw some immediatedrops in water surface

(52:10):
elevations, and we have gagereadings at a number of places
along the river, like atVicksburg and Memphis, and up
around Greenville, Mississippi,and in some places we saw an
immediate drop in water surfaceelevations 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 seethat dramatic of a change in big
river systems, that, and that'sthe biggest, most dramatic
change of anything I've seen onthe Mississippi River was the
effect in the response of thosecutoffs initially, you know,

(52:56):
south of Memphis. As a result ofthat, that shortening of the
river, the slopes increasedanywhere from 30% to about 90%
That's the water surface slopes.
So I'm getting back to my streampower with an increase of 30 to
90% slopes,the stream powersprobably increased, you know,

(53:20):
accordingly, and with thatamount of stream power, the
river is, and the sedimentsupply coming in hasn't changed.
Then the river has got a lotmore stream power than it does
sediment coming into it, so it'sthe river starts thinking about
I've gotta go find some moresediment to move, and that's

(53:42):
what happens. You now can, it'llstart scouring the bed, scouring
the banks, it'll start trying toremeander, and this is what was
happening. And so we hadtremendous increases in the
sediment transport capacity, andthat triggered what we call head
cutting, which I mentionedearlier. You get these over

(54:04):
steepened slopes, and thatstarts migrating upstream
through time.
The other side of that is thatincreased slope and sediment
transport is now pulsingaccelerated sediment loads
downstream, and so it gets tothe system effect. We've got to

(54:28):
think about how all thissediment is being transported
and how it relates downstream aswell as upstream. And just to
complicate this issue a littlebit, above Memphis, and this is
rarely talked about, but aboveMemphis, there were a number of

(54:48):
chute cutoffs, these smallerchute cutoffs that occurred in
the 1930s through the 1950s andthere were about 20 of these
chute cutoffs that had beendocumented that shorten the
river 20, 25 miles. And so nowwe had response upstream of
Memphis to those shoot cutoffs,which could have been pulsing

(55:11):
more sediment downstream intothe cutoff, reaches downstream
of Memphis, which could actuallydampen the head cutting
processes, because we're oversupplying sediment from
upstream.
So again, when that's what I'mjust trying to, to emphasize how
complex these these channelresponses get, and we can't just

(55:33):
focus at one location, we haveto look at that whole system.
So, so even today, that was, wemade those cutoffs 80, 90 years
ago. We are still seeingresponse on the river today, you
know, 80 or 90 years later,moving up toward Cairo. So we're

(55:55):
seeing that degradational trendmigrate upstream, and that's one
of the areas of research that wehave is trying to understand,
well, how much more degradationis going to migrate up toward
Cairo and beyond, how much it'sgoing to go up the Ohio, it
could go up the Middle Miss, andwhat happens then. So that's a,

(56:16):
that's an area of research thatwe have right now.
So that was, that's about asquick as I could talk about the
cutoff, I usually talk foreveron them, but the, but to add on
to the cutoffs, as I mentioned,after the cutoffs were made, the
last cutoff, Ferguson cutoff wasin 1942, but the river was

(56:40):
actually trying to remeander. Itwas trying to regain that
length, and that's what riversdo. And so there was a period
from the 1940s until the Corpsgot the banks revetted. So,
beginning in the 1950s the Corpsof Engineers started to revet
the banks, putting - when I sayrevet the banks, we're talking

(57:02):
about putting concretemattresses now, is what we're
using to revet and protect themeanders to not allow them to
erode anymore.
So, by the 1960s the mid early1960s the pretty much all the
meander bins from Cairo down tothe Gulf are locked in place

(57:25):
with revetments. So we've nowtaken away that degree of
freedom that the river used tohave, because you know you
mentioned earlier about, youknow, changes in how the river
responds, and the river is stillgoing to respond to the cutoffs
and but now we don't allow theriver to meander, so all the all

(57:49):
the adjustments are occurring inthe vertical, they can't go
lateral anymore, so it just, theriver is still going, going to
try to respond, it just going tobe a different response than it
would have been under a morenatural 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 degradationregime say upstream of the
Arkansas River, from there upmoving toward Cairo, and we see
that that degradation is justnow getting into the region just

(58:26):
south of Cairo, so it'smigrating upstream. We have
downstream of the ArkansasRiver, the river is actually
transitions to equilibrium, ormaybe slightly aggradational
down toward Vicksburg andNatchez. So it's a, it's a
complex response, but it'sreally a typical response to a
series of cutoffs. But these,but that response is not just

(58:50):
the cutoffs, and that's where Iwas going, is that it's the
cutoffs are probably the mostdramatic immediate change on the
river, increasing that slopethat dramatically, but now we've
got the revetments. We've nowstopped the river from
meandering, and if you recall, Isaid prior to the 1930s the

(59:13):
average annual supply ofsediment from the banks between
Cairo and Baton Rouge was about600 million tons per year. Well,
now it's essentially zero. It'sno longer being supplied to the
river.
So, what's the consequences ofthat? The, you know, a lot of

(59:33):
that sediment is fine sediments,the silts and clays, the wash
load. Well, that's a reductionin that wash load is delivered
down to the Gulf. There'simpacts there. There's a lot of
environmental habitat waterquality issues with that.
There's also a lot of coresediments, sands, gravels in

(59:53):
these banks. That's no longerbeing supplied. How is the river
responding to that reducedsediment supply coming from the
bank. So that can contribute tothe channel response as well. So
that's just one issue.
There's also beginning in the1960s we began constructing the

(01:00:17):
dike systems on the river. Theseare transverse riprap structures
that extend out into thechannel, and these are
navigation structures, andthey're designed to cut off the
side channels and the secondarychannels, and to force more of
the water into the main channelto reduce maintenance dredging.

(01:00:39):
And with that, with respect toreducing 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 secondaryeffects, and some of the
negative impacts might be thatwe're actually closing off some

(01:01:02):
of these side channels, and froma habitat perspective, that's a
negative issue.
So now, and I'm sure JackKilgore talked about this, some
of the restoration work that'sbeing 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

(01:01:25):
the dikes to allow more water tocome through those, those
secondary channels from ahabitat perspective. So, the
Corps is working pretty closewith the fish and wildlife to
construct these dike notches.
But there's a lot of sedimentthat's been trapped in these
dike fields, which again we'reremoving some sediment from the
system.

(01:01:47):
So all of these features arecombining are being integrated
to to capture that, or to thatcause this channel response that
we're seeing degradationmigrating upstream, aggradation
and stability downstream. It'shard to single out, you know,

(01:02:08):
how much relative impact thecutoffs, the revetments, the
dikes, the levees. You know,it's hard to actually quantify,
you know, what relative percenteach of these is contributing,
and I actually try not to,because it just almost gives me
a headache trying to think abouthow to do that, but you know,

(01:02:31):
cumulatively the river isresponding to all of this, and
and so the present day river iscompletely different than
Charles Dickens' river, that hesaw, and hopefully he would see
a better river today. Maybe hewould see it even worse. I don't
know.
But we've actually transformed akind of wider bar island

(01:02:53):
dominated slightly aggradationalsystem to a more single channel,
more efficient channel that'sdesigned for flood control
navigation. The interesting partof it is even today our channel
slopes in the present day riverare still anywhere from 10 to 15

(01:03:16):
to upwards of 60% higher thanthey were pre 1930s and as a
result, we've got a lot morestream power in the river. As I
mentioned, we have degradationoccurring upstream of the
Arkansas River, but downstreamthe river is actually

(01:03:37):
aggradational or in equilibrium,and that comes back to that one
of their initial questions youhad about the reduction in the
sediment loads on the river andit being complex, we talked
about the sediment loads beingreduced 50 to 85% and that's

(01:03:57):
primarily that that finesediment loads that I mentioned
that's measured in suspendedsediment calculations, but this
is where I'm saying that the bedmaterial sediment loads at core
settlement loads are actuallyhigher than they used to be,
because our slopes and streampower are so much higher in the

(01:04:18):
river, and we have plenty ofsand and gravel in the river for
supply, it's there to be moved,and we have reaches, for
instance, here at Vicksburg, theslopes on the river are maybe 15
to 20% higher than they used tobe, yet the river is actually

(01:04:39):
slightly aggradational. Thatmeans it's filling up with
sediment, so if this, if theslopes were 20%, 15 to 20%
higher, yet the sediment loadshad reduced 85% we'd be scouring
to China here at Vicksburg, we'dbe, it would be eroding like

(01:04:59):
crazy.
But it's not, and that's where Icome from, saying we need to
think about the core sedimentswhen we think about these, these
bed material or wash loadreductions in the sediment
loads.

Dean Klinkenberg (01:05:13):
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, degradationaltendency on the above Memphis,
around Memphis, so talking abouta deeper channel at that point,
essentially.

Dr. David Biedenharn (01:05:29):
Yeah, the channel is, it's very
complicated. The degradation wesee, you know, you can have the
channel bed decreasing, watersurfaces are coming down, a lot
of it's just because of theincreased slopes that, but yeah,
typically you would see thechannel enlarging, and we see

(01:05:49):
that when we compare comparativesurveys through time, we've seen
an increase in that area, and alot of that has to be through
the bed deepening, is you know,because the banks are revetted
and diked on the other side, butwe are seeing an increase in
area and channel volume.

Dean Klinkenberg (01:06:11):
So the reverse of that, then does that mean
there's a tendency for someparts below there for the
channel bed to be rising alittle bit?

Dr. David Biedenharn (01:06:21):
Yes. The downstream, when we compare the
channel surveys, we see a lossof area, cross-sectional area
volume in the river. So we'reseeing a loss of volume and area
in the river downstream, anincrease upstream.

Dean Klinkenberg (01:06:37):
And then, so that loss of volume downstream
certainly would have someimplications for flood control,
I would imagine.

Dr. David Biedenharn (01:06:43):
Exactly, yes. And that's where you have
to look at that and say, allright, how is this going to
impact long-term flood control,levee height, that type of
thing. Right now we're in goodshape, but you know what's it
going to be like in 100 years,200 years.

Dean Klinkenberg (01:06:59):
Yeah, interesting. I've had, I've been
lucky enough to walk on somegravel bars on the Lower
Mississippi. They're fascinatingplaces, but so I guess that's
part of the, that is some of thesource of those bigger chunks of
sediment. Some of the gravelbars, when the river's higher,
it can pick up content from thegravel bars, or you know, maybe

(01:07:19):
rocks that are stuck into thebanks and move that further
downriver, so because of theincreased velocity of the river,
now we can carry some of thosefurther down river because of
that,

Dr. David Biedenharn (01:07:32):
Right, and and then we have to think about,
as I mentioned, what is the longterm future of the river going
to look like with all thesechanges and complications, and
that's where it gets reallyinteresting. And a number of

(01:07:52):
years ago, the Corps created aprogram within the MR&T called
the Mississippi RiverGeomorphology and Potamology
Program, and that's what it'saimed at doing, is trying to
understand all these complexprocesses and interactions that
I've discussed, and how is thatgoing to affect the future of

(01:08:17):
the river, and when I say thefuture, I'm thinking 50, 100
years, 200 years. I think weneed to be thinking out that
far, and it's we don't alwayshave tools and ways to be to
quantify things 100 or 200 yearsfrom now, but we need to start
trying to look in thatdirection, and that's that's one

(01:08:37):
of the things we're trying to dowith MRGMP program is to think
about what's the river systemgoing to be 100 years from now,
or 200 years, you know.
My, my goal is I want theengineers and scientists 100 or
200 years from now to look backon us and say they may not have
really known everything that wasgoing on, and they probably

(01:08:58):
missed and were wrong on anumber of things, but at least
they established a program and aprotocol for moving forward that
we're today in a better positionto manage the river, you know,
for another 200 years. So that'sthat's my long-term goal.

Dean Klinkenberg (01:09:14):
So if we don't do anything differently for the
next couple decades or 50 yearsor whatever, what would you
picture the Mississippi would belike 50 years from now if we
didn't change anything?

Dr. David Biedenharn (01:09:27):
Well, in 50 years, I think you know, 50
years for me is a long time, butfor the Mississippi is not that
long. But I think we would see acontinuation of the trends that
we're seeing, a long slowdegradational process moving
upstream, the degradation movingup toward Cairo. I think will

(01:09:52):
continue. It's going to be at aslow rate. We might lose another
few feet in degradation. We'llprobably see some more
aggradation on the downstream,and so we'll see kind of a
continuation of those existingtrends, that's what I would
envision.

Dean Klinkenberg (01:10:09):
Yeah, I think one of the things that's really
interesting to me, as somebodywho doesn't have to make these
decisions, is how difficult itis to develop a plan when you
have so many competing, or notnecessarily competing, but so
many factors that aren'tnecessarily complementary. You

(01:10:32):
pull a lever over here, and youget this consequence down here.
We can create a river that flowsfaster and self-scours to some
degree, and makes it better fornavigation, but then we've
degraded some of the ecosystemsfor the life off the main
channel, and all of this isrelatively expensive as well.

(01:10:54):
Dredging, dredging, the dredgingbudget is pretty enormous for
the Corps, and most of that's onthe Lower Mississippi.
Maintaining these structures isnot cheap, so like from from
your point of view, like whatcan you tell me, I know there
are congressional mandates, butlike how in an ideal world, how
do we go about balancing allthese different factors and

(01:11:15):
making decisions about how tomanage this beast of a river?

Dr. David Biedenharn (01:11:21):
Wow.

Dean Klinkenberg (01:11:21):
Above your pay grade?

Dr. David Biedenharn (01:11:23):
Above my pay grade, Dean, but, but that's
a more complication, morecomplicated question than some
of the technical questions. Wecan technically, you know, if
you tell me we, we want floodcontrol and nothing else, we can
give you flood control, youknow, for whatever event, almost
we can make that happen. Butthat's probably not going to sit

(01:11:45):
well with a lot of the users andthe other people in the valley,
which we have to think about,you know, their their viewpoints
and impacts to their lives andtheir livelihoods, and that's
where it gets to be verycomplicated.
As we mentioned, we can changethings to, you know, if it's

(01:12:06):
just a single goal, single, youknow, objective. That's simple,
but it's no longer singleobjectives. We've got multiple
objectives, and most of them arenot moving along the same path,
and that's where it gets socomplicated, and we almost
always run into that. You know,we could, we could restore the

(01:12:28):
entire Mississippi River, wecould, we could do away with the
revetments and the levees, andlet the valley have the
floodplain again. That, youknow, of course, that would have
consequences. We'd probably losenavigation, flood control
wouldn't exist. We'd have usnatural, more natural
environment out there, butthat's probably not going to

(01:12:48):
happen. And so it's just, it'sjust, it's hard to satisfy all
the different groups, and that'sthat's where I'm glad I'm not
the one having to make thosedecisions, I'm just a technical
geek trying to understand theriver.

Dean Klinkenberg (01:13:07):
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'velearned about the Mississippi
from all these years?

Dr. David Biedenharn (01:13:17):
The gosh, I think just the connectivity of
the system, and understand, andthis translates, not just the
Mississippi, translates to smallstreams everywhere, is that we
can't just drop into the riverat one location where there's a

(01:13:38):
problem and put our blinders onand think about fixing that
particular problem withoutthinking about how that reach
fits into the system upstreamand downstream and how what we
might do to change something atthat local reach is going to
have impacts upstream anddownstream. And then how those

(01:14:00):
secondary impacts will havelonger term trends as well, so
we have this complex responsethat we see. We see it because
we have such a long record onthe Mississippi. We can see that
complex response, and that'salways been a learning thing for
me, and it applies, you know, instreams all over the country and

(01:14:24):
all over the world.

Dean Klinkenberg (01:14:26):
Fantastic. So, do you have a favorite spot to
go to on the river, like forfishing or partying, or just
hanging out?

Dr. David Biedenharn (01:14:37):
Not really. We used to have a nice
lounge on the Mississippi,called Delta, the Delta Point, I
think was the name. It was rightthere above the bridge at
Vicksburg, and had this reallynice lounge that you could sit
and just look out through thesewindows, and you can sit there
in the evenings and have a havea drink and watch the river
flow, and then the casino camein, and then they tore that

(01:15:01):
down, and so my favorite spot isgone. So I don't have that spot
anymore.

Dean Klinkenberg (01:15:08):
Bummer.

Dr. David Biedenharn (01:15:09):
Yeah, it is.

Dean Klinkenberg (01:15:12):
It's been a while since I've been down
there. I remember reallyenjoying St. Catherine Creek
National Wildlife Refuge, butthat's a little further south.

Dr. David Biedenharn (01:15:20):
Yeah.

Dean Klinkenberg (01:15:21):
But I thought that was a beautiful area.

Dr. David Biedenharn (01:15:25):
Yeah.

Dean Klinkenberg (01:15:26):
Well, David, is there anything else you feel
like we didn't cover that youwant to add before we wrap this
up?

Dr. David Biedenharn (01:15:34):
Gosh, I'm trying to remember what I, what
I said in the last hour so.

Dean Klinkenberg (01:15:39):
We just got a master class, I think, so.

Dr. David Biedenharn (01:15:41):
I don't know, we got something, but hope
I didn't ramble and babble toomuch, so.

Dean Klinkenberg (01:15:49):
No, that was fantastic, and you explained it
very clearly, so I deeplyappreciate your time and sharing
your expertise with us, andthank you again, like hopefully
this, you know, maybe it'llraise a few questions, maybe
people will reach out and havesome questions. Is there a place
where people can follow the workthat you're doing?

Dr. David Biedenharn (01:16:11):
There is.
If they go, I don't have thelink to tell you right now, but
if you go on to the Corps ofEngineers Mississippi Valley
Division Office, there's aMississippi River Geomorphology
and Potamology site there, andthere's a lot of information

(01:16:32):
there about some of the studiesthat have that have gone on.
That's one place, there's alsothe here at ERDC, we have a
library, you can go to the ERDClibrary, and if you have
particular authors or people ortopics you're interested in, you

(01:16:54):
might can research and find somepublications there.

Dean Klinkenberg (01:16:58):
All right, we will search those out, and I can
put links to those in the shownotes for folks. So, well, thank
you very much, David. Grateful,deeply appreciate your time
today.

Dr. David Biedenharn (01:17:10):
All right, if you ever get to Vicksburg,
come see us.

Dean Klinkenberg (01:17:13):
Thanks for listening. If you enjoyed this
episode, subscribe to the serieson your favorite podcast app, so
you don't miss out on futureepisodes. I offer the podcast
for free, but when you supportthe show with a few bucks
through Patreon you help keepthe program going. Just go to
patreon.com/deanklinkenberg. Ifyou want to know more about the

(01:17:34):
Mississippi River, check out mybooks. I write the Mississippi
Valley Traveler guidebooks forpeople who want to get to know
the Mississippi better. I alsowrite the Frank Dodge Mystery
Series that's set in placesalong the river. Find them
wherever books are sold. TheMississippi Valley Traveler
podcast is written and producedby me, Dean Klinkenberg.
Original music by Noah Fence.
you next time.