August 20, 2022 • 31 mins
Fuelled once again by Christine's insatiable curiosity, today Talk Description to Me explores the visuals of river systems. How do rivers form? Are the headwaters obvious? Are stream networks visible in satellite images? Does a river in the Amazon look the same as a river in Egypt? With the help of diagrams, descriptions of maps, and tactile primers on continental geography, JJ and Christine dive headfirst into the cool, rushing waters of the world's great rivers.
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JJ Hunt (00:03):
Talk description to me is Christine Malec and JJ Hunt
Christine Malec (00:27):
Hi, I'm Christine Malec.
JJ Hunt (00:28):
And I'm JJ Hunt. This is talk description to me, where
the visuals of current eventsand the world around us get
hashed out in description richconversations.
Christine Malec (00:47):
As with so many of our previous episodes, this
episode came out of a kind of alifelong curiosity of mine about
river systems. And as someonewho grew up blind, I, I kind of
remember the moment it was, youknow, shockingly late in my in
my education process where,okay, I was still a kid, but
(01:08):
where I realized rivers don'tjust start and flow straight
down to the ocean and empty intoit. They're really twisty and
windy and complicated. And Ididn't know that not having seen
maps. And so the more I learnedabout them, the more I learned
how complex they are. So today,we're going to talk about
waterways, specifically riversystems, and how they interact
(01:32):
with the land and how the landinteracts with them. And what
what the behavior of riversystems is, and we're going to
definitely be looking at somespecific examples, and how they
fit into the landscape and whatthey do. So, JJ, for this, you
use some satellite data andsatellite images as a starting
(01:53):
point, right?
JJ Hunt (01:54):
Yeah, I looked at some satellite images also looked at
a lot of diagrams, I found thatbetween the satellite images and
the diagrams, you get a prettydecent understanding of the
systems and how they work riveror stream systems. When you look
at them in a diagram, orsometimes in satellite images,
(02:14):
they look like Bear trees,they've got these thick trunks
with a wide base of major routesthat are connected to a large
body of water, like an ocean ora sea or lake or something like
that, then then the big trunkthat goes up from there, and
then wide branches that come offof the trunk, these are the main
tributaries, and then fromthere, smaller branches and
(02:36):
twigs that come off of the mainbranches, these are the little
streams, not kind of descriptionis in reverse of the way it
actually works. Of course, thewater starts in those tiny
little streams, those littletwigs and branches, comes down
toward the connect with enjoyingthe kind of, you know, larger
branches of water, thetributaries, those then feed
(02:56):
into the trunk of the tree thatthen come out into into the
roots, which are like the deltasthat connect to major bodies of
water. And the diagrams of riversystems, I think are often used
in textbooks and in videoexplainers, diagrams that that
really emphasize this patternthat I've just described.
(03:18):
Because even when the satelliteimages are readily available,
the diagrams can can really drawattention to those smaller
streams and tributaries. Insatellite images, those often
get left out, because they just,they're just not, they're just
not clearly visible. So asatellite image of a river
system might be taken fromhundreds, maybe even 1000s of
(03:40):
kilometers above sea level, anda stream that's only 10 feet
wide with, with trees growing onboth sides of the bank, that's
just not going to show up. I'msure the experts can see the
visual evidence I can cat youknow, configure it, a little bit
of it. But for the purposes ofeducation, the diagram is often
the thing.
Christine Malec (03:58):
So you already challenged an idea that I had by
saying that the what you'resaying is that the head of a
river, like where it starts isnot necessarily obvious. I
always assumed like, oh, okay,that's the starting point.
That's really obvious. But theway you're describing it is a
little branch let's feeding intosomething bigger and bigger and
(04:20):
bigger. And it's a bit almostlike the reverse of how I
pictured it. So is it everunclear what the actual head of
a river is like the actualstarting point?
JJ Hunt (04:30):
Yeah, I think it is.
Rivers are fed by lots ofdifferent types of water, right?
You've got rainwater, you've gotglacial melt. There's also
groundwater ins and springs,those feed river systems as
well. And so there are someareas where the clear part of
the river the tributary or thestream that might be that might
be clear, you know, there's acut in the soil. There's a
(04:53):
there's a you know, some kind ofhollow in the land and and water
is running down it, that's astream that's clear. But the
groundwater that kind of bubblesup and becomes swamp land,
that's part of the river systemas well. So the wetlands that
feed into those streams, thoseare all part of the river system
(05:15):
of a stream network. So therainwater, the glacial melt, the
groundwater, all of that flowsinto the small streams, those
streams converge into branches,those gather into the main
trunk, you know, so on and soforth. And then when they get
close to the big body of waterthat they are releasing into,
(05:36):
that's when you get these flatdeltas, because a lot of the
sediment has been carried downby the water deposited in this
flat land that builds up thisflat land. And then that's what
floods and creates these deltasthat then release into into the
sea or the ocean and whatnot.
Christine Malec (06:00):
And so I guess you've answered my question that
was brewing for me is, is thatwhy a diagram might be more
effective than a satellite imagebecause it labels things and
traces that out for you?
JJ Hunt (06:14):
That's right, it labels things, it traces it clearly. If
you're looking at a satelliteimage, if you are an expert, you
might know that this brown patchin the satellite image
represents a kind of swampyarea. And in that swampy area,
we know that the elevation ofthat swamp is higher than this
(06:35):
thin blue squiggle that appears,you know, a down, you know
downslope from that, and sotherefore, that water is feeding
that stream. But to thelayperson, who's looking at
that, that might not be clear.
Whereas if you have a nicearrow, blue arrow on a green
piece of land that points like,here's where the, you know,
(06:57):
here's the wetland, and here'swhere the stream is going. It's
just more clear than asatellite. I've got an image of
a satellite here, an examplethat I pulled up from the NASA's
Earth Observatory website, thisimage was taken in 2019. This
is, was taken at a time when thewater levels in the Mississippi
and the Missouri rivers in thesouthern US they were very, very
(07:21):
high. This image is a high resfull color satellite picture of
the southern part of theMississippi. And, you know, it's
got state borders, overlaid andfine white lines, but it's
mostly just about the geographyhere. Visually. This image shows
the main trunk of theMississippi running south from
(07:43):
about the southeast tip ofMissouri, near Kentucky and
Illinois. But in fact, the riversystem actually starts far, far,
far north of that it starts nearthe Canadian border. There's
water that's pulled in from thatfar away. But it's not always
clear in these satellite imagesin this satellite image of the
(08:07):
lower half the lower portion ofthe Mississippi, the river
system looks like a tall,narrow, windblown tree, that
kind of leans a little bit tothe right near the base of the
tree kind of moving up, there'sa branch that breaks off to our
left into Louisiana, but themain trunk kind of angles up to
(08:29):
our right, and that the trunk ofthe Mississippi that creates the
divide between Louisiana andabove it Arkansas, which is on
our left or the West, andMississippi and above it
Tennessee to our right or to theeast. And then about halfway up
of Mississippi there's this wideblue patch that looks kind of
(08:50):
like a knot or a burl if we'resticking with this tree
metaphor. This is Delta NationalForest part of the Mississippi's
floodplain. And then above thatnorth of the Louisiana Arkansas
border, there's a branch thatgoes off to the left this
creates a bit of a V shape thatI believe is the Arkansas River
going off to the left and theMississippi that's the right
(09:13):
side of the V shape and thatcarries on up and up and up up
the top of our image and thenagain eventually fades away into
this you know green area that isstill feeding that's still the
headwaters coming down from thesouth. So it's amazing and again
keep in mind this roots updescription that I've just given
(09:33):
us backwards, the water flowsfrom the tiny twigs, the which
of the streams into the largerbranches then into the trunk and
I say that over and over againbecause visually, I sometimes
find that hard to remember likewhen you write or water on the
ground. It comes the water, youknow flows from the source this
bucket or whatever that you'vedumped water out of. And then it
(09:55):
slowly creeps out and becomesthese You know, into little tiny
streams or trickles along theearth. But in fact, this is the
opposite the little tiny streamsor trickles, that's where the
water is coming from feedinginto the big branch and then
going into the major body ofwater, the lake or the sea or
(10:16):
the ocean.
Christine Malec (10:19):
I play like to understand deltas better. And I
feel like from my memory of atactile map of the Nile, I feel
like the Nile is a good exampleto start with, because unlike
many rivers, it's it's actuallysort of straight compared to
other rivers. So can we kind ofuse that as an example and also
and describe the delta thathappens when it reaches the
(10:41):
Mediterranean.
JJ Hunt (10:42):
So the Nile Delta is kind of extraordinary, because
of just how green it is,compared to the rest of the
landscape. You know, the NileDelta is in Egypt, at the north
end of the of the country whereit reaches the Mediterranean.
And yes, so the river, the NileRiver has gone in a more or less
(11:06):
straight line. And when you lookat a satellite image, the Nile
river looks green, because it isbordered by trees, vegetation
growing right along either sideof the relatively straight and
narrow, for the most part, notthat narrow, but it looks narrow
compared to the deserts oneither sides. On the satellite
(11:29):
image, you've got desert to theright desert to the left, and
then a relatively straight greenthin line that comes up through
the middle, that's the Nile andthe vegetation on either side.
And then as it approaches theMediterranean in a satellite
image, it fans out into a greatbig V. And everything in that is
(11:50):
green, it's lush, there arethings growing, this is the
floodplain. And right along theborder, like right along the
shore, really of theMediterranean, that's when you
get city. So that's an urbancenter there right along. And so
some within that green, there'skind of this green and gray
(12:11):
patch, which is where it isurban, but there's still
vegetation, there's still life.
And that's what it looks likewhen it is when things are lush,
if you look at the diagram ofthat, you can actually see
individual like rivulets, youcan see little streams, you can
see those roots, that that go into, you know, that branch out
(12:33):
into the water. But when thearea is is either flooded, or,
or the you know, the vegetationhas grown, you can't see those
individual streams, the wholearea just looks green and lush.
Christine Malec (12:49):
I want to try my hand at a bit of describing
because this wasn't clear to meuntil I was able to check out a
tactile map. And if I'm right,the Nile makes kind of a Y
shape. So it's coming from southto north. And then when it hits
the Mediterranean, it depositsall of this silt and soil and
stuff to make this triangularformation of land so that you
(13:12):
end up I think, at theMediterranean, the Nile kind of
splits around this triangulardelta. So there's water flowing,
sort of northeast and northwestaround the delta. And so the
delta is a triangular result ofdeposits from the Nile, is that
right?
JJ Hunt (13:31):
Yeah, that's absolutely right. With the line coming up
from the bottom, from from theSouth to the North, it's a
little bit bendy, but it's, youknow, more or less straight, and
then you've got, you know, the vshape on top of that, that
triangular shape on top of that,that triangle with the line
coming at the bottom that's verymuch a Y shape.
Christine Malec (13:49):
And from a human perspective, what happens
on Delta's like, Are therecities on that delta people live
there? And if they do, is it akind of a canal based area where
you would need boats or a lot ofbridges to get across the
rivulets?
JJ Hunt (14:05):
Yeah, definitely, you need a lot of you need
infrastructure to deal withthis, right. So either because
you are expecting floodingregularly, or because there just
might be a flood at some point.
Or because this is just wetland, you need to have, you
know, ways to deal with that insome places where the canals in
the Delta are clearer than youhave. Yeah, then you have canal
(14:28):
based systems where where peopleare traveling by boat, from
place to place that just makessense for their way of, of
getting around in other placeswhere you might just be needing,
you might just be prepared forfloods, as opposed to living
without water day in and dayout. And maybe you're going to
(14:48):
you're going to build yourinfrastructure in a different
way. I've got an image here,which is a flood plain. So it's
not a Delta but it's afloodplain of the Nile. This is
in Sioux, then and this image isit's quite something, it's a
hazy picture. So it's a littlebit hard to make out. The city
that's in the background. Sostarts in the background, this
(15:09):
hazy city, and jutting outtoward us from the city is this
point of green land with a fewhigh rises on it. And then all
around that point, reallyoccupying the most of the image
is flooded land. And it's, it'svery difficult to say how large
(15:29):
an area the flood is because thecamera angle was clearly chosen
to emphasize just how vast itis. And you know, so the camera
angles playing a little bit of atrick on us. But it's a huge
expanse of flooded land, thiskind of muddy water, and then
rising out of the muddy water,these little kind of organized
(15:50):
pads of green, so they're kindof making little islands. And I
don't know what this land wouldlook like without the flood. But
with it, it's just this big,huge muddy water like a big
expanse. And then leading fromthe, that green point in the
center coming, you know, that'scoming toward us off to our
(16:14):
right are two very long, thinbridges that from this angle
look like they're barely abovethe water. So this is clearly
how they've built theirinfrastructure. They know it's a
floodplain, they know it's goingto be flooding, you got bridges
to get on and off this, youknow, this green point in the
middle, because it's likely thatthis floodplain has some water
(16:35):
in it all the time. And rightnow, it's just at a high point
where the water is right up tothe green point. And you know,
taking over the entire image.
Christine Malec (16:48):
As a historical geek moment, I want to point out
that if you've read about thehistory of Egypt, you might know
about lower Egypt and UpperEgypt. And it's
counterintuitive, because UpperEgypt refers to closer to the
head of the Nile, which is southand Lower Egypt is north, which
refers to the lower, loweraspect of the river. And the the
(17:12):
origin of the Nile is notactually an Egypt, right? It's,
it's more in the southern partof Africa or the middle part of
Africa.
JJ Hunt (17:19):
Yeah, yeah. Closer to the middle. So the Nile runs,
like you say, north in EastAfrica. So it runs north, and
it's in East Africa, it runsfrom Lake Victoria, which is in
Uganda, and Tanzania. And itruns through South Sudan and
Sudan, up through Egypt. Andthat's when it drains out into
the Mediterranean. So I find itreally helpful to have a mental
(17:42):
picture of maps and landforms inmy head, when I'm talking about
different parts of the world. Solet's try and make the continent
of Africa a little bit easier topicture. Okay, so take your
right hand and make a thumbsdown. So your palm is facing
away from you and the back ofyour hand that is pointed
(18:03):
towards you. Now, open up yourknuckles just a little bit so
that you're not making a tightfist. So your knuckles are just
kind of loosened, they're openedup a little bit. So your
knuckles above the rings, ifyou've ring any rings, those are
pointing to your left, yourthumb is pointing down. That is
kind of the shape of Africa. Soyour knuckles, those are Western
(18:26):
Africa, your thumb, that'sSouthern Africa horn, yes,
that's right. And that the topthe pinky side of your hand,
that's Northern Africa. Now,this isn't perfect, the thumb
Southern Africa that is quite abit bigger than your actual
thumb like relative to the restof your hand, that's a bigger
chunk. But that's more or lesswhere it's placed. And it does
(18:49):
kind of it does stick down likethat. That's the basic shape to
the left of your thumb. That'sthe South Atlantic to the right
of your thumb, that's the IndianOcean, and your wrist, that's
the Red Sea. The risk is the RedSea, which separates Africa from
Saudi Arabia. So the Nile in youknow, relative to this hand, the
(19:11):
Nile runs north from a more orless than knuckle on your thumb,
which is inland but not very farfrom the eastern coast, it runs
from your knuckle, all the wayup across the back of your hand
kind of more or less parallel toyour wrist, which is more or
less parallel to the Red Sea.
And then it dumps into theMediterranean Sea on the pinky
side of your hand, just to theleft of your wrist. And that
(19:35):
journey from about your knuckleacross the back of your hand.
That's about 6800 kilometers4200 miles.
Christine Malec (19:46):
Wow. And as a side note, when we did the
episode on the Suez Canal,that's kind of roughly where the
Suez Canal was going to the eastof the Nile, right?
JJ Hunt (19:55):
That's exactly right.
Because it's connecting that RedSea there's a little tiny bit of
Land paths the Red Sea that theyhad to break through it to get
into into the Mediterranean.
That's absolutely right.
Christine Malec (20:09):
So the Nile being a more or less
straightforward image on a on asatellite map sort of heading
from south to north. Let's talkabout something that's maybe
more complex. And the the AmazonI think is the is the largest
river in the world by volume.
JJ Hunt (20:26):
Yeah, it is massive. So the Amazon cuts across the top
of South America, the headwatersstart on the mountains, which
run down the west coast of thesubcontinent. And then the main
stem crosses Brazil and thenempties into the North Atlantic
on the East Coast. And, yeah, itis. It's enormous. It's about
(20:50):
the network, the system coversabout 7 million square
kilometers, which forcomparison, that's 10 times the
size of France. It's enormous.
It stretches from Colombia inthe north Ecuador and Peru to
the west and Bolivia and CentralBrazil in the south, more water
is discharged from the Amazon,then then the next seven largest
(21:14):
rivers combined. Well, it'shuge. So in satellite images, I
needed to zoom out to about 5000kilometers above the surface of
the Earth, according to Google,to get the entire subcontinent
wide base and on my laptopscreen. And at that height, not
many of the tributaries areclear. It's a big, fairly round
(21:38):
patch that looks lush and reallydark green, perhaps the darkest,
most thoroughly green patch onall of Google Earth. But from
this height, only the main stemsare evident. In fact, they look
like very fine brown lines thatare overlaid on the image, like
they look like border lines.
(22:01):
It's only when you zoom in, andyou see how squiggly those lines
are that you realize, oh, wait aminute, those are waterways,
those are borderlines, those arewaterways, you need a diagram of
the Amazon to really get a senseof how many tributaries, how
many streams, how all of thoseare feeding into this main
trunk, this main stem that cutsmore or less horizontally across
(22:26):
the top of the subcontinent?
Christine Malec (22:29):
No rivers do things to the land and land does
things to the rivers? And is theAmazon a good example, to talk
about those kinds ofinteractions over, you know,
lots of time?
JJ Hunt (22:41):
I mean, there's so many different pathways that are
coming together. And if you'vegot different kinds of different
kinds of land different kinds ofmaterial like rock or how soft
the rock is, or what's thevegetation that's already there,
what's the climate, like, what'sthe elevation drop, all of those
things will change how a riverinteracts with the land, and how
(23:02):
the land forms the river and allof that. So for the Amazon, so
I've got an image here of asunset over what looks like a
really wide Lake, there's just ahint of a tree line and the
distance that are left and ahint of a tree line at a
distance on a right. But at thecenter in the distance, it's
open, there is no tree line. Andthat's the only hint that this
(23:24):
is a river, not a giant lake,the water is not entirely hemmed
in. Otherwise, this is a big,wide, calm looking Lake. You
know, Lake body, and in fact,rivers do at some points, form
lakes, and then just keep going.
And that's that's what theAmazon looks like. In this
particular image. In anotherphoto, there are two very wide
(23:45):
rivers that enter the image atour upper left, and they're just
separated by this point of land,we just get a little tiny point
of land up in the upper left.
It's blanketed in like denselypacked, lush green trees. And so
there's a river on either sideof this point of water that come
(24:06):
together and they converge. Andthey form a single river that
moves through the image downtoward our lower right. So this
is two rivers coming together toform an even larger river that's
coming down. This largertributary is also lined with
thick, green rainforest. Thescale of this image is it's
(24:29):
massive, like it just looks likethis, you know, thick blanket of
green trees. And only when youzoom in, can you actually see
one or two trunks and yourealize, wow, if that's a trunk
of the tree that large, there'snothing human built in here. So
there's no way to to get thescale. It's only when you you
see the the trunk of one ofthese trees when you zoom in
(24:50):
that you realize that this is amassive scale. So then you can
move to something like theColorado so the Colorado is in a
completely different climate.
I'm starting it is starting inmountains the same way that that
the Amazon is starting inmountains. But then it doesn't
go through rain forest, theColorado goes through desert, it
goes through very differentkinds of rock material. So the
(25:12):
river looks quite different. Sothe Colorado starts in the
central Rocky Mountains in thestate of Colorado, and then
flows southwest through youknow, Canyon, specifically the
Grand Canyon. The river doesn'tquite make it out of the
Colorado Delta anymore, it wouldhave emptied into the Gulf of
(25:34):
California. But at this point,it's tapped dry with dams and
irrigation and basic urban watersupply. So the Colorado delta is
more or less dry at this point.
And of course, one of the thingsthat's so very impressive about
the Colorado River is that ithelped carve the Grand Canyon,
(25:57):
so high in the mountains. That'swhere the headwaters are, it's
lush and green up there. I'vegot an image here of a winding
river, the shores dotted withevergreen trees, there are snow
capped mountains in the distancevery, you know, lovely, you
know, typical mountain scene, itstarts to gain strength, the
Colorado River starts to gaingain strength from all of the
(26:19):
tributaries, all of thesemountains with their, you know,
their snow capped mountains, allof that, that that snow was
melting, rushing down, the riverstarts to get pretty swift. And
that's when you get the classicwhitewater streams or rivers
right, churning water, rockyshores. And then as the Colorado
moves south, the climate getsdrier, and the river starts to
(26:41):
encounter increasingly deepgorges of bare rock. And this is
when we start getting the canyonlandscapes that the area is very
well known for red rock cliffsand gorges that are lined with
the striations of the ages, verylittle vegetation, really just
rock wall valleys and this riverwinding along at the bottom.
Christine Malec (27:06):
There's some terms in river talk that I don't
understand. Can we talk about anOxbow?
JJ Hunt (27:13):
Okay, so an Oxbow river can become an oxbow lake. So you
know, the rivers we'll find,we'll find their path, right?
When they're when they'rerushing hard and they're high,
their elevation drop issignificant, they're going more
or less straight, when they'reslowing down. That's when you
(27:34):
often get this winding thismeander this back and forth,
it's a very sin us kind of snakelike back and forth, back and
forth. And one of the thingsthat that can do as it goes back
and forth, the back and forthcan get kind of loopy. So on
each time that you're going, ifyou're basically making a figure
eight shape with your finger,like you point your finger, just
(27:56):
draw figure eight, it's kind ofthat kind of back and forth. But
you're then moving forward,you're still you're still
progressing. But those loopseach time you make a loop and
then turn around and loop in theother direction, you create a U
shape. That is that's part ofthat meander. And if one of
those, the back and forth, Ushape connects, it can it can,
(28:21):
you know, basically form afreestanding body of water in
one of those loops that can thenflood. So instead of just having
this river outline, it joins asit as it kind of swoops back in.
And that area will either createan island in the middle of a
Round Lake, or the entire areacan flood. And then it's and
(28:46):
then you've just got a roundpool that's at the side of
another wise, you know,continuing to flow River.
Unknown (28:53):
What does it mean to say a rapids?
JJ Hunt (28:57):
So when you're up, usually higher in the river
network. So when your yourelevation drop is significant,
the water is churning. That'sthat's a rapid, the water is
rapidly moving through an areaand they tend to have lots of
rocks. So first of all, you'vegot to have a channel that can
hold that kind of watermovement, it won't turn into
(29:19):
that kind of rapid. If you havea sandy bottom, for example,
because it'll just wash all theway you generally need some kind
of harder material on the sidesof the bottom. Also, if you've
got rocks, bigger rocks on theon the sides and bottom, the
water is going to churn in acertain way. It's not just going
(29:39):
to flow straight, like it'sflowing down a pipe, there's
more agitation, there's moremovement in the water. And so
then you get the water goingrapidly down down slope, you've
got the water hitting theserocks and churning, and that's
when you get like white caps andyou get little whirlpools and
things so if you're white Got arafting or something, you're
(30:02):
looking for these kinds of areasthat are navigable. But you know
a little bit dicey because thewater is going fast, it is
churning, and there are rocks inthe way. So that's what, that's
what a rapids looks like.
Christine Malec (30:20):
On Saturday, August the 27th 2022, we'll be
posting our last episode of Talkdescription to me. For now, the
show was more popular than it'sever been. And we're still
firmly committed to descriptionrich programming. But there's
been a tectonic shift in thefinancial position of the
podcast, so we're going onhiatus to regroup and reimagine
(30:41):
our model. The world ofdescription is evolving fast,
and funding models for creatorsand innovators haven't kept up.
We're currently exploring newpartnerships and envisioning new
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(31:03):
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stay subscribe to our podcastfeed and our social media will
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Talk description to me is Christine Malec and JJ Hunt
Christine Malec (00:27):
Hi, I'm Christine Malec.
JJ Hunt (00:28):
And I'm JJ Hunt. This is talk description to me, where
the visuals of current eventsand the world around us get
hashed out in description richconversations.
Christine Malec (00:47):
As with so many of our previous episodes, this
episode came out of a kind of alifelong curiosity of mine about
river systems. And as someonewho grew up blind, I, I kind of
remember the moment it was, youknow, shockingly late in my in
my education process where,okay, I was still a kid, but
(01:08):
where I realized rivers don'tjust start and flow straight
down to the ocean and empty intoit. They're really twisty and
windy and complicated. And Ididn't know that not having seen
maps. And so the more I learnedabout them, the more I learned
how complex they are. So today,we're going to talk about
waterways, specifically riversystems, and how they interact
(01:32):
with the land and how the landinteracts with them. And what
what the behavior of riversystems is, and we're going to
definitely be looking at somespecific examples, and how they
fit into the landscape and whatthey do. So, JJ, for this, you
use some satellite data andsatellite images as a starting
(01:53):
point, right?
JJ Hunt (01:54):
Yeah, I looked at some satellite images also looked at
a lot of diagrams, I found thatbetween the satellite images and
the diagrams, you get a prettydecent understanding of the
systems and how they work riveror stream systems. When you look
at them in a diagram, orsometimes in satellite images,
(02:14):
they look like Bear trees,they've got these thick trunks
with a wide base of major routesthat are connected to a large
body of water, like an ocean ora sea or lake or something like
that, then then the big trunkthat goes up from there, and
then wide branches that come offof the trunk, these are the main
tributaries, and then fromthere, smaller branches and
(02:36):
twigs that come off of the mainbranches, these are the little
streams, not kind of descriptionis in reverse of the way it
actually works. Of course, thewater starts in those tiny
little streams, those littletwigs and branches, comes down
toward the connect with enjoyingthe kind of, you know, larger
branches of water, thetributaries, those then feed
(02:56):
into the trunk of the tree thatthen come out into into the
roots, which are like the deltasthat connect to major bodies of
water. And the diagrams of riversystems, I think are often used
in textbooks and in videoexplainers, diagrams that that
really emphasize this patternthat I've just described.
(03:18):
Because even when the satelliteimages are readily available,
the diagrams can can really drawattention to those smaller
streams and tributaries. Insatellite images, those often
get left out, because they just,they're just not, they're just
not clearly visible. So asatellite image of a river
system might be taken fromhundreds, maybe even 1000s of
(03:40):
kilometers above sea level, anda stream that's only 10 feet
wide with, with trees growing onboth sides of the bank, that's
just not going to show up. I'msure the experts can see the
visual evidence I can cat youknow, configure it, a little bit
of it. But for the purposes ofeducation, the diagram is often
the thing.
Christine Malec (03:58):
So you already challenged an idea that I had by
saying that the what you'resaying is that the head of a
river, like where it starts isnot necessarily obvious. I
always assumed like, oh, okay,that's the starting point.
That's really obvious. But theway you're describing it is a
little branch let's feeding intosomething bigger and bigger and
(04:20):
bigger. And it's a bit almostlike the reverse of how I
pictured it. So is it everunclear what the actual head of
a river is like the actualstarting point?
JJ Hunt (04:30):
Yeah, I think it is.
Rivers are fed by lots ofdifferent types of water, right?
You've got rainwater, you've gotglacial melt. There's also
groundwater ins and springs,those feed river systems as
well. And so there are someareas where the clear part of
the river the tributary or thestream that might be that might
be clear, you know, there's acut in the soil. There's a
(04:53):
there's a you know, some kind ofhollow in the land and and water
is running down it, that's astream that's clear. But the
groundwater that kind of bubblesup and becomes swamp land,
that's part of the river systemas well. So the wetlands that
feed into those streams, thoseare all part of the river system
(05:15):
of a stream network. So therainwater, the glacial melt, the
groundwater, all of that flowsinto the small streams, those
streams converge into branches,those gather into the main
trunk, you know, so on and soforth. And then when they get
close to the big body of waterthat they are releasing into,
(05:36):
that's when you get these flatdeltas, because a lot of the
sediment has been carried downby the water deposited in this
flat land that builds up thisflat land. And then that's what
floods and creates these deltasthat then release into into the
sea or the ocean and whatnot.
Christine Malec (06:00):
And so I guess you've answered my question that
was brewing for me is, is thatwhy a diagram might be more
effective than a satellite imagebecause it labels things and
traces that out for you?
JJ Hunt (06:14):
That's right, it labels things, it traces it clearly. If
you're looking at a satelliteimage, if you are an expert, you
might know that this brown patchin the satellite image
represents a kind of swampyarea. And in that swampy area,
we know that the elevation ofthat swamp is higher than this
(06:35):
thin blue squiggle that appears,you know, a down, you know
downslope from that, and sotherefore, that water is feeding
that stream. But to thelayperson, who's looking at
that, that might not be clear.
Whereas if you have a nicearrow, blue arrow on a green
piece of land that points like,here's where the, you know,
(06:57):
here's the wetland, and here'swhere the stream is going. It's
just more clear than asatellite. I've got an image of
a satellite here, an examplethat I pulled up from the NASA's
Earth Observatory website, thisimage was taken in 2019. This
is, was taken at a time when thewater levels in the Mississippi
and the Missouri rivers in thesouthern US they were very, very
(07:21):
high. This image is a high resfull color satellite picture of
the southern part of theMississippi. And, you know, it's
got state borders, overlaid andfine white lines, but it's
mostly just about the geographyhere. Visually. This image shows
the main trunk of theMississippi running south from
(07:43):
about the southeast tip ofMissouri, near Kentucky and
Illinois. But in fact, the riversystem actually starts far, far,
far north of that it starts nearthe Canadian border. There's
water that's pulled in from thatfar away. But it's not always
clear in these satellite imagesin this satellite image of the
(08:07):
lower half the lower portion ofthe Mississippi, the river
system looks like a tall,narrow, windblown tree, that
kind of leans a little bit tothe right near the base of the
tree kind of moving up, there'sa branch that breaks off to our
left into Louisiana, but themain trunk kind of angles up to
(08:29):
our right, and that the trunk ofthe Mississippi that creates the
divide between Louisiana andabove it Arkansas, which is on
our left or the West, andMississippi and above it
Tennessee to our right or to theeast. And then about halfway up
of Mississippi there's this wideblue patch that looks kind of
(08:50):
like a knot or a burl if we'resticking with this tree
metaphor. This is Delta NationalForest part of the Mississippi's
floodplain. And then above thatnorth of the Louisiana Arkansas
border, there's a branch thatgoes off to the left this
creates a bit of a V shape thatI believe is the Arkansas River
going off to the left and theMississippi that's the right
(09:13):
side of the V shape and thatcarries on up and up and up up
the top of our image and thenagain eventually fades away into
this you know green area that isstill feeding that's still the
headwaters coming down from thesouth. So it's amazing and again
keep in mind this roots updescription that I've just given
(09:33):
us backwards, the water flowsfrom the tiny twigs, the which
of the streams into the largerbranches then into the trunk and
I say that over and over againbecause visually, I sometimes
find that hard to remember likewhen you write or water on the
ground. It comes the water, youknow flows from the source this
bucket or whatever that you'vedumped water out of. And then it
(09:55):
slowly creeps out and becomesthese You know, into little tiny
streams or trickles along theearth. But in fact, this is the
opposite the little tiny streamsor trickles, that's where the
water is coming from feedinginto the big branch and then
going into the major body ofwater, the lake or the sea or
(10:16):
the ocean.
Christine Malec (10:19):
I play like to understand deltas better. And I
feel like from my memory of atactile map of the Nile, I feel
like the Nile is a good exampleto start with, because unlike
many rivers, it's it's actuallysort of straight compared to
other rivers. So can we kind ofuse that as an example and also
and describe the delta thathappens when it reaches the
(10:41):
Mediterranean.
JJ Hunt (10:42):
So the Nile Delta is kind of extraordinary, because
of just how green it is,compared to the rest of the
landscape. You know, the NileDelta is in Egypt, at the north
end of the of the country whereit reaches the Mediterranean.
And yes, so the river, the NileRiver has gone in a more or less
(11:06):
straight line. And when you lookat a satellite image, the Nile
river looks green, because it isbordered by trees, vegetation
growing right along either sideof the relatively straight and
narrow, for the most part, notthat narrow, but it looks narrow
compared to the deserts oneither sides. On the satellite
(11:29):
image, you've got desert to theright desert to the left, and
then a relatively straight greenthin line that comes up through
the middle, that's the Nile andthe vegetation on either side.
And then as it approaches theMediterranean in a satellite
image, it fans out into a greatbig V. And everything in that is
(11:50):
green, it's lush, there arethings growing, this is the
floodplain. And right along theborder, like right along the
shore, really of theMediterranean, that's when you
get city. So that's an urbancenter there right along. And so
some within that green, there'skind of this green and gray
(12:11):
patch, which is where it isurban, but there's still
vegetation, there's still life.
And that's what it looks likewhen it is when things are lush,
if you look at the diagram ofthat, you can actually see
individual like rivulets, youcan see little streams, you can
see those roots, that that go into, you know, that branch out
(12:33):
into the water. But when thearea is is either flooded, or,
or the you know, the vegetationhas grown, you can't see those
individual streams, the wholearea just looks green and lush.
Christine Malec (12:49):
I want to try my hand at a bit of describing
because this wasn't clear to meuntil I was able to check out a
tactile map. And if I'm right,the Nile makes kind of a Y
shape. So it's coming from southto north. And then when it hits
the Mediterranean, it depositsall of this silt and soil and
stuff to make this triangularformation of land so that you
(13:12):
end up I think, at theMediterranean, the Nile kind of
splits around this triangulardelta. So there's water flowing,
sort of northeast and northwestaround the delta. And so the
delta is a triangular result ofdeposits from the Nile, is that
right?
JJ Hunt (13:31):
Yeah, that's absolutely right. With the line coming up
from the bottom, from from theSouth to the North, it's a
little bit bendy, but it's, youknow, more or less straight, and
then you've got, you know, the vshape on top of that, that
triangular shape on top of that,that triangle with the line
coming at the bottom that's verymuch a Y shape.
Christine Malec (13:49):
And from a human perspective, what happens
on Delta's like, Are therecities on that delta people live
there? And if they do, is it akind of a canal based area where
you would need boats or a lot ofbridges to get across the
rivulets?
JJ Hunt (14:05):
Yeah, definitely, you need a lot of you need
infrastructure to deal withthis, right. So either because
you are expecting floodingregularly, or because there just
might be a flood at some point.
Or because this is just wetland, you need to have, you
know, ways to deal with that insome places where the canals in
the Delta are clearer than youhave. Yeah, then you have canal
(14:28):
based systems where where peopleare traveling by boat, from
place to place that just makessense for their way of, of
getting around in other placeswhere you might just be needing,
you might just be prepared forfloods, as opposed to living
without water day in and dayout. And maybe you're going to
(14:48):
you're going to build yourinfrastructure in a different
way. I've got an image here,which is a flood plain. So it's
not a Delta but it's afloodplain of the Nile. This is
in Sioux, then and this image isit's quite something, it's a
hazy picture. So it's a littlebit hard to make out. The city
that's in the background. Sostarts in the background, this
(15:09):
hazy city, and jutting outtoward us from the city is this
point of green land with a fewhigh rises on it. And then all
around that point, reallyoccupying the most of the image
is flooded land. And it's, it'svery difficult to say how large
(15:29):
an area the flood is because thecamera angle was clearly chosen
to emphasize just how vast itis. And you know, so the camera
angles playing a little bit of atrick on us. But it's a huge
expanse of flooded land, thiskind of muddy water, and then
rising out of the muddy water,these little kind of organized
(15:50):
pads of green, so they're kindof making little islands. And I
don't know what this land wouldlook like without the flood. But
with it, it's just this big,huge muddy water like a big
expanse. And then leading fromthe, that green point in the
center coming, you know, that'scoming toward us off to our
(16:14):
right are two very long, thinbridges that from this angle
look like they're barely abovethe water. So this is clearly
how they've built theirinfrastructure. They know it's a
floodplain, they know it's goingto be flooding, you got bridges
to get on and off this, youknow, this green point in the
middle, because it's likely thatthis floodplain has some water
(16:35):
in it all the time. And rightnow, it's just at a high point
where the water is right up tothe green point. And you know,
taking over the entire image.
Christine Malec (16:48):
As a historical geek moment, I want to point out
that if you've read about thehistory of Egypt, you might know
about lower Egypt and UpperEgypt. And it's
counterintuitive, because UpperEgypt refers to closer to the
head of the Nile, which is southand Lower Egypt is north, which
refers to the lower, loweraspect of the river. And the the
(17:12):
origin of the Nile is notactually an Egypt, right? It's,
it's more in the southern partof Africa or the middle part of
Africa.
JJ Hunt (17:19):
Yeah, yeah. Closer to the middle. So the Nile runs,
like you say, north in EastAfrica. So it runs north, and
it's in East Africa, it runsfrom Lake Victoria, which is in
Uganda, and Tanzania. And itruns through South Sudan and
Sudan, up through Egypt. Andthat's when it drains out into
the Mediterranean. So I find itreally helpful to have a mental
(17:42):
picture of maps and landforms inmy head, when I'm talking about
different parts of the world. Solet's try and make the continent
of Africa a little bit easier topicture. Okay, so take your
right hand and make a thumbsdown. So your palm is facing
away from you and the back ofyour hand that is pointed
(18:03):
towards you. Now, open up yourknuckles just a little bit so
that you're not making a tightfist. So your knuckles are just
kind of loosened, they're openedup a little bit. So your
knuckles above the rings, ifyou've ring any rings, those are
pointing to your left, yourthumb is pointing down. That is
kind of the shape of Africa. Soyour knuckles, those are Western
(18:26):
Africa, your thumb, that'sSouthern Africa horn, yes,
that's right. And that the topthe pinky side of your hand,
that's Northern Africa. Now,this isn't perfect, the thumb
Southern Africa that is quite abit bigger than your actual
thumb like relative to the restof your hand, that's a bigger
chunk. But that's more or lesswhere it's placed. And it does
(18:49):
kind of it does stick down likethat. That's the basic shape to
the left of your thumb. That'sthe South Atlantic to the right
of your thumb, that's the IndianOcean, and your wrist, that's
the Red Sea. The risk is the RedSea, which separates Africa from
Saudi Arabia. So the Nile in youknow, relative to this hand, the
(19:11):
Nile runs north from a more orless than knuckle on your thumb,
which is inland but not very farfrom the eastern coast, it runs
from your knuckle, all the wayup across the back of your hand
kind of more or less parallel toyour wrist, which is more or
less parallel to the Red Sea.
And then it dumps into theMediterranean Sea on the pinky
side of your hand, just to theleft of your wrist. And that
(19:35):
journey from about your knuckleacross the back of your hand.
That's about 6800 kilometers4200 miles.
Christine Malec (19:46):
Wow. And as a side note, when we did the
episode on the Suez Canal,that's kind of roughly where the
Suez Canal was going to the eastof the Nile, right?
JJ Hunt (19:55):
That's exactly right.
Because it's connecting that RedSea there's a little tiny bit of
Land paths the Red Sea that theyhad to break through it to get
into into the Mediterranean.
That's absolutely right.
Christine Malec (20:09):
So the Nile being a more or less
straightforward image on a on asatellite map sort of heading
from south to north. Let's talkabout something that's maybe
more complex. And the the AmazonI think is the is the largest
river in the world by volume.
JJ Hunt (20:26):
Yeah, it is massive. So the Amazon cuts across the top
of South America, the headwatersstart on the mountains, which
run down the west coast of thesubcontinent. And then the main
stem crosses Brazil and thenempties into the North Atlantic
on the East Coast. And, yeah, itis. It's enormous. It's about
(20:50):
the network, the system coversabout 7 million square
kilometers, which forcomparison, that's 10 times the
size of France. It's enormous.
It stretches from Colombia inthe north Ecuador and Peru to
the west and Bolivia and CentralBrazil in the south, more water
is discharged from the Amazon,then then the next seven largest
(21:14):
rivers combined. Well, it'shuge. So in satellite images, I
needed to zoom out to about 5000kilometers above the surface of
the Earth, according to Google,to get the entire subcontinent
wide base and on my laptopscreen. And at that height, not
many of the tributaries areclear. It's a big, fairly round
(21:38):
patch that looks lush and reallydark green, perhaps the darkest,
most thoroughly green patch onall of Google Earth. But from
this height, only the main stemsare evident. In fact, they look
like very fine brown lines thatare overlaid on the image, like
they look like border lines.
(22:01):
It's only when you zoom in, andyou see how squiggly those lines
are that you realize, oh, wait aminute, those are waterways,
those are borderlines, those arewaterways, you need a diagram of
the Amazon to really get a senseof how many tributaries, how
many streams, how all of thoseare feeding into this main
trunk, this main stem that cutsmore or less horizontally across
(22:26):
the top of the subcontinent?
Christine Malec (22:29):
No rivers do things to the land and land does
things to the rivers? And is theAmazon a good example, to talk
about those kinds ofinteractions over, you know,
lots of time?
JJ Hunt (22:41):
I mean, there's so many different pathways that are
coming together. And if you'vegot different kinds of different
kinds of land different kinds ofmaterial like rock or how soft
the rock is, or what's thevegetation that's already there,
what's the climate, like, what'sthe elevation drop, all of those
things will change how a riverinteracts with the land, and how
(23:02):
the land forms the river and allof that. So for the Amazon, so
I've got an image here of asunset over what looks like a
really wide Lake, there's just ahint of a tree line and the
distance that are left and ahint of a tree line at a
distance on a right. But at thecenter in the distance, it's
open, there is no tree line. Andthat's the only hint that this
(23:24):
is a river, not a giant lake,the water is not entirely hemmed
in. Otherwise, this is a big,wide, calm looking Lake. You
know, Lake body, and in fact,rivers do at some points, form
lakes, and then just keep going.
And that's that's what theAmazon looks like. In this
particular image. In anotherphoto, there are two very wide
(23:45):
rivers that enter the image atour upper left, and they're just
separated by this point of land,we just get a little tiny point
of land up in the upper left.
It's blanketed in like denselypacked, lush green trees. And so
there's a river on either sideof this point of water that come
(24:06):
together and they converge. Andthey form a single river that
moves through the image downtoward our lower right. So this
is two rivers coming together toform an even larger river that's
coming down. This largertributary is also lined with
thick, green rainforest. Thescale of this image is it's
(24:29):
massive, like it just looks likethis, you know, thick blanket of
green trees. And only when youzoom in, can you actually see
one or two trunks and yourealize, wow, if that's a trunk
of the tree that large, there'snothing human built in here. So
there's no way to to get thescale. It's only when you you
see the the trunk of one ofthese trees when you zoom in
(24:50):
that you realize that this is amassive scale. So then you can
move to something like theColorado so the Colorado is in a
completely different climate.
I'm starting it is starting inmountains the same way that that
the Amazon is starting inmountains. But then it doesn't
go through rain forest, theColorado goes through desert, it
goes through very differentkinds of rock material. So the
(25:12):
river looks quite different. Sothe Colorado starts in the
central Rocky Mountains in thestate of Colorado, and then
flows southwest through youknow, Canyon, specifically the
Grand Canyon. The river doesn'tquite make it out of the
Colorado Delta anymore, it wouldhave emptied into the Gulf of
(25:34):
California. But at this point,it's tapped dry with dams and
irrigation and basic urban watersupply. So the Colorado delta is
more or less dry at this point.
And of course, one of the thingsthat's so very impressive about
the Colorado River is that ithelped carve the Grand Canyon,
(25:57):
so high in the mountains. That'swhere the headwaters are, it's
lush and green up there. I'vegot an image here of a winding
river, the shores dotted withevergreen trees, there are snow
capped mountains in the distancevery, you know, lovely, you
know, typical mountain scene, itstarts to gain strength, the
Colorado River starts to gaingain strength from all of the
(26:19):
tributaries, all of thesemountains with their, you know,
their snow capped mountains, allof that, that that snow was
melting, rushing down, the riverstarts to get pretty swift. And
that's when you get the classicwhitewater streams or rivers
right, churning water, rockyshores. And then as the Colorado
moves south, the climate getsdrier, and the river starts to
(26:41):
encounter increasingly deepgorges of bare rock. And this is
when we start getting the canyonlandscapes that the area is very
well known for red rock cliffsand gorges that are lined with
the striations of the ages, verylittle vegetation, really just
rock wall valleys and this riverwinding along at the bottom.
Christine Malec (27:06):
There's some terms in river talk that I don't
understand. Can we talk about anOxbow?
JJ Hunt (27:13):
Okay, so an Oxbow river can become an oxbow lake. So you
know, the rivers we'll find,we'll find their path, right?
When they're when they'rerushing hard and they're high,
their elevation drop issignificant, they're going more
or less straight, when they'reslowing down. That's when you
(27:34):
often get this winding thismeander this back and forth,
it's a very sin us kind of snakelike back and forth, back and
forth. And one of the thingsthat that can do as it goes back
and forth, the back and forthcan get kind of loopy. So on
each time that you're going, ifyou're basically making a figure
eight shape with your finger,like you point your finger, just
(27:56):
draw figure eight, it's kind ofthat kind of back and forth. But
you're then moving forward,you're still you're still
progressing. But those loopseach time you make a loop and
then turn around and loop in theother direction, you create a U
shape. That is that's part ofthat meander. And if one of
those, the back and forth, Ushape connects, it can it can,
(28:21):
you know, basically form afreestanding body of water in
one of those loops that can thenflood. So instead of just having
this river outline, it joins asit as it kind of swoops back in.
And that area will either createan island in the middle of a
Round Lake, or the entire areacan flood. And then it's and
(28:46):
then you've just got a roundpool that's at the side of
another wise, you know,continuing to flow River.
Unknown (28:53):
What does it mean to say a rapids?
JJ Hunt (28:57):
So when you're up, usually higher in the river
network. So when your yourelevation drop is significant,
the water is churning. That'sthat's a rapid, the water is
rapidly moving through an areaand they tend to have lots of
rocks. So first of all, you'vegot to have a channel that can
hold that kind of watermovement, it won't turn into
(29:19):
that kind of rapid. If you havea sandy bottom, for example,
because it'll just wash all theway you generally need some kind
of harder material on the sidesof the bottom. Also, if you've
got rocks, bigger rocks on theon the sides and bottom, the
water is going to churn in acertain way. It's not just going
(29:39):
to flow straight, like it'sflowing down a pipe, there's
more agitation, there's moremovement in the water. And so
then you get the water goingrapidly down down slope, you've
got the water hitting theserocks and churning, and that's
when you get like white caps andyou get little whirlpools and
things so if you're white Got arafting or something, you're
(30:02):
looking for these kinds of areasthat are navigable. But you know
a little bit dicey because thewater is going fast, it is
churning, and there are rocks inthe way. So that's what, that's
what a rapids looks like.
Christine Malec (30:20):
On Saturday, August the 27th 2022, we'll be
posting our last episode of Talkdescription to me. For now, the
show was more popular than it'sever been. And we're still
firmly committed to descriptionrich programming. But there's
been a tectonic shift in thefinancial position of the
podcast, so we're going onhiatus to regroup and reimagine
(30:41):
our model. The world ofdescription is evolving fast,
and funding models for creatorsand innovators haven't kept up.
We're currently exploring newpartnerships and envisioning new
platforms that will not onlyallow us to keep creating
content, but will also provideopportunities for other
innovative creators, describersand allies to expand our
(31:03):
collective view of what can bedescribed and how we hope you'll
stay subscribe to our podcastfeed and our social media will
be quieter, but we'll still bearound. New episodes might pop
up now and again, as worldevents unfold, and you can stay
in touch with our otherdescription related projects.
We'll be closing our Patreonpage for the time being
(31:25):
limitless gratitude to those whostepped up to help support us,
either with funds or withfeedback. Stay tuned, there's
more to come
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Does hearing about a true crime case always leave you scouring the internet for the truth behind the story? Dive into your next mystery with Crime Junkie. Every Monday, join your host Ashley Flowers as she unravels all the details of infamous and underreported true crime cases with her best friend Brit Prawat. From cold cases to missing persons and heroes in our community who seek justice, Crime Junkie is your destination for theories and stories you won’t hear anywhere else. Whether you're a seasoned true crime enthusiast or new to the genre, you'll find yourself on the edge of your seat awaiting a new episode every Monday. If you can never get enough true crime... Congratulations, you’ve found your people. Follow to join a community of Crime Junkies! Crime Junkie is presented by audiochuck Media Company.
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If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.