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USGS Public Lecture Series: A Field Trip to the Congo--Hydroacoustic measurements in "the river that swallows all rivers."
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Matthew Larsen: Hello, everyone. Thanks for waiting patiently. We’re just a few minutes behind our schedule, but it’s the inevitable delay at coming in the door through our security procedures being in a Federal Building. So thanks for your patience. Thanks for tolerating the security rules. I’m Matt Larsen,  I’m the Associate Director for Water here at the US Geological Survey, formerly known as the Chief Hydrologis, less symbols in that title.



00:46



I want to welcome you to our third in a series of Science in Action lectures and these are meant to introduce to a broad audience here in the Northern Virginia area are some of the science areas we’re focusing on in this agency and we’re delighted to have so many people here in the audience. We’re in for a treat.  Our speaker is John Shelton. He is up here in Reston from our USGS office in South Carolina. John has worked for the USGS for about 16 years.



01:23



Prior to South Carolina, he worked in our Florida office and then prior to that in our Tennessee office.  Among other things, he has taught a number of hydroacoustic courses in Canada, Great Britain; and in 2006, worked in the Tigris River in Northern Iraq. You’re probably wondering what a hydroacoustic course is. I’m going to leave you in suspense because you’ll learn about it from him. One hint is that orange modern( looking surfboard over there. You’ll hear more about that from John as well.



01:56



So John had the interesting experience among others of working in Iraq and was among members of the team to install the first new stream flow stations in Iraq. I think you could still find those data on the web, am I right John?


John Shelton : Yes, sir.



02:15



They’re not easily found, but they are there. Getting to the end of my remarks, I’ll just tell you that last year John was on a team that worked in Africa on the Congo River. It was a research team with the American Museum of National History.  He and his team were able to document parts of the river among other things that were deeper than 700 feet; perhaps making the Congo the deepest river in the world. So I’m going to let John take the stage and you’ll learn a lot more about that part of the world. Thanks. John?


[Applause]



02:59



John Shelton: Good evening. Can everybody hear me OK?


Audience: Yeah.


Audience: A little.



03:02



John Shelton: I kind of get to wander around a little bit, but I’ve been instructed to make sure I kind of stay in front of this microphone. So I’ll try to stay over here. If I get too antsy, I’ll try not to wander in front of the screen. I’ve been on several international missions. I guess, Matt said in Great Britain in 2006, I get to go to Africa and Iraq and then this presentation is on my trip to the Congo and I told the group earlier today that I’ve been very pleased with my opportunities to do hydrology work in these foreign countries and I thought it was because people had confidence in my skills and abilities and were sending me to these place, but when I came to Reston, I was enlightened and I was talking to a gentleman he said, “Wow, who did you make mad !”



03:48



[Laughter]


So I’m not sure that they’re sending me to these places because of my abilities or they’ve been trying to knock me off. I can't figure that out. Tonight, this is not going to be a technical presentation at all. I’m a storyteller, so I’ll try to kind of go over my whole month in Africa as a story.  I will show some of the results that we were able to get in technical graphs and charts towards the end, but I’ll try to explain it the best I can. But for the most part, it’s going to be a story.



04:19



Our whole trip was featured on a National Geographic Explorer episode called “Monster Fish in the Congo”. So parts of this presentation, I’ve taken clips from that episode and kind of embedded them in the presentation so we’ll get to see a few short movies in there.  Title of this presentation is "A Field Trip to the Congo, Hydroacoustic Measurements in the River that Swallows all Rivers." I’m going to try to follow this outline the best I can.



04:50



I’ll give you a brief history of the Congo River Project and how it got started, and AMNH is the American Museum of Natural History and they were the primary investigators on this project, specifically the Ichthyology Department at AMNH. Then we will move  into field verification of model predictions. There were some AMNH were looking at specific hydraulic conditions in the lower Congo and we had a USGS scientists in Connecticut who modeled the river. Actually, it was him who said it will be great if we could get USGS personnel on the ground to kind of verify what we predicted here, so I owe him this trip.



05:31



And then last but not the least, acoustic and water quality measurements. That’s kind of where I fit in to this and some of the projects that I worked on. Our primary purpose was fish diversity definition. I’ll talk more about that on the next slide. OSW is the USGS Office of Surface Water here at headquarters. We wanted to… There’s not many opportunities to be able to collect data on a river this size. So we had some specific instrumentation tests that we wanted to try to complete while we were over there.



06:03



Turbulence definition: not only is the Congo River the second largest river in the world, but it’s also an incredibly turbulent river with unbelievable boils and whirlpools that are just of a magnitude that’s almost hard to comprehend.  We also, while we were there, collected water quality samples. We were collecting (inaudible) parameters from the boat and we’re collecting physical grab samples at most of the tributaries on the river and having them analyzed when we got back stateside.



06:34



And then the two points on the right are bathymetry and discharge. Those were the two points that I was primarily involved with.  Bathymetry is going to be the mapping of the bedform. We wanted to be able to paint a three-dimensional picture of what the bed of the Congo River looked like in the region where we were studying. In concert with that, we were also mapping three-dimensional velocity field. We wanted to be able to show what the water was doing as it was crossing these irregular bedforms.



07:02



And then we wanted to come up with the total flow. How much water is there in the lower Congo. The project started from the American Museum of Natural History in New York City. The PI on this project is Dr. Melanie Stiassny. She is the Head of the Ichthyology Department and part of her life’s goal, I guess, is fish species determination on the African continent. The Democratic Republic of Congo is the second African county she’s worked on and this was her second trip there.



07:41



Her primary goal there was looking at fish species in the lower Congo. There is just an unbelievable amount of diversity, but they’re incredibly diverse populations. You might find one species in this location and then you go across the river and there’s something totally different or even downstream. Go downstream on the same bank and that species you just found upriver is not there anymore. They’re totally segregated in these pocketed populations.


What she was trying to figure out was what physical structures or hydraulic structures in the river make these fish so isolated. Why is there no interaction or integration? So that was kind of where we came in to play. We going to try to determine what features in the river were causing this fish to act like this.



08:32



You can see the blowup from the upper left of the African continent.  That outlined area that we’re looking at is the draining basin for the Congo River. The Congo drains pretty much the entire central portion of the African continent. That drainage area is about 1.4 million square miles. It’s above the Mississippi. If you know, the drainage basin for the Mississippi takes up most of the center of the US and it’s about 1.2 million square miles. Congo is the number two river directly behind the Amazon and it’s followed closely by the Mau.



09:13



We were there, actually, we went on this project last year and we measured about 1.3 million cubic feet per second. I’ll get more into that later, as that was one of the highlights we’re going to look at. I’m going to take a step back and make some qualifications to what I’m going to talk to you about tonight. I started my career in Tennessee and I moved to Florida. I worked in Florida for a few years, now in South Carolina and I’m studying Hydrology in Africa. So I’m already a little bit out of my element.



09:47



But now I’m also going to talk about Geology and Biology, of which I know absolutely nothing about. So, no questions whatsoever on those two subjects. But I’m going to try to talk a little bit about central African geology and how the Congo River was formed. There is suspect that somewhere between 400,000 years ago and 35 million years ago that central Africa, and the Congo River was a closed basin. There were no major outfalls to the Atlantic Ocean.



10:19



There might have been some minor rivers that are coming out of the Congo and make it into the ocean, but as far as a mainstream river that actually reached, it wasn’t existent. It was primarily a centrally drained basin that formed. You can see here the central Congo basin, the major tributaries coming in. At some point during this time period, during that 400,000 to 35 million years ago, there was a great catastrophic geologic event that ripped apart western Africa, somewhere in this area.



10:54



So when this event occurred, it ripped the country apart, it allowed the Congo River to complete its path towards the ocean and formed the lower Congo River. It’s pretty evident when you’re looking at the physics of the Congo River. It’s upstream in these rifs, the Congo River is totally different than the last hundred miles. The last hundred miles is incredibly turbulent, much narrower, the bed is much more irregular. And irregularity, I’m talking about because it has this huge chimneys.



11:30



Chimneys, being these big rock pillars coming up from the bottom that could be anywhere from 200 to 400 feet just rising above the bottom. The same place you can have tabletops, which would be like shelves in the river where you have these flat areas and then suddenly they drop off. It could drop off to depths of 500 or 600 feet – totally irregular, not at all like the smooth river channels we’re used seeing in the US.



12:00



If you look on this map, this little yellow circle was indicating Pool Malebo and that’s a section of the river that’s about somewhere between 14 and 15 miles across. It’s a really braided channel and somewhere in this area is probably where the original plug was. It is from this point forward that the river has these unique characteristics that we were just talking about. And this is the area of our study. From just below Kinshasa is about 85 miles down to Pioka and we studied on down to this area. But this is the lower Congo River, the lower Congo Rapids, and this is where we did all our work.



12:45



Kinshasa is the capital of the Democratic Republic of the Congo. The Democratic Republic of Congo was formerly the country of Zaire. It occurred 20 plus years ago, I guess. In this area just north of Kinshasa, this is the country of Congo. So the river is the national boundary between the DRC and Congo. Kind of another side pont,  where I get to go on these international ventures where I’m trying to get knocked off and I had one of my colleagues tell me, he said, “John, you know,” he said, “any country that starts with democratic republic of anything is probably not one you want to be visiting.”


[Laughter]



13:30



We did have a good time, though, it was a great trip. This is looking at the change in elevation of that last 350 kilometers. From Pool Malebo, which is this area here on the map, and then you can see the change in elevation all the way down to Matadi which is in this area. There’s two primary jumps or falls that will show up as pretty extreme rapids and that’s  in this area. I’ll talk about this later in the presentation. And then this extreme change in elevation here, that’s all down in this area. That’s the area known as Inga.



14:09



Inga is the area that’s just… we flew over it and were taking pictures. Congolese Government actually has some dam building projects in that area for electricity, hydroelectric generation and with that kind of fall in the river, though, it’s an awesome sight to see that quantity of water changing elevation that rapidly. It’s unbelievable. This is what we were looking at. These are the fish species that have been identified in the lower Congo River.



15:05



Currently, I think the museums  been there twice and in those two visits, they’ve found at least 135 species and that number is on the rise. Of those 135, 30% of them were found only in the lower Congo River. They’re totally localized and found nowhere else in the world.


You can see we were finding some pretty unique-looking fish. This is... to me these look like animals out of Dr. Seuss books or fairy tales.[Laughter] In the National Geographic episode, they caught one of my candid moments where I referred to the fish in the Lower Congo River as a 'freak fish Garden of Eden.'


[Laughter]


And of course that made the cut, and now they're using it as one of the little promo clips and so my boss is constantly reminding me of my eloquence.


[Laughter]


Yes. Speaking with that strong Southern accent just doesn't do a whole lot for accountability. [Laughter] This is... Well, look. This is the Lower Congo, Malebo Pool in the upper right-hand corner. We're just going to kind of quickly look at three different fish species.



16:03



You can see here that the green, yellow and red dots represent individual species. So the green dot being Lamprologus werneri, and they're only found in those green dots. Once they reach this portion of the River, species changes. You don't find them anymore. They're gone. It's only that one short little range that you can find werneri.


The yellow dots represent Lamprologus tigripictilis, and they're found--after werneri disappears, they go all the way down in the area of Inga.


And then the red dot is this good fish we tell stories about. This is Lamprologus lethops and you can see lethops, we got another picture of him over here. He has no pigment, he's totally white and has no eyes. He has skin covering the areas where you expect to find the eyes.



17:00



So just looking at those features of the fish, I mean, the first thought that comes to mind is he’s a depth dweller, he lives in areas of extreme depth where there is no sunlight penetration, so there is no skin pigmentation and there's no need for eyes because it's so dark. This fish had only been found--I think it was identified on the first trip, and they only ever found dead specimens of these fish. I'll back up another hundred seconds.


All these are cichlids, so they're relatively small species. The title of the National Geographic episode is "Monster Fish of the Congo". 'Monster fish' refers to the giant Tiger fish, Goliath Tiger fish, and there was another research project going on looking at those, but I have to believe that National Geographic knew that if you said "six-inch little cichlid fish in the Congo" [Laughter] you probably wouldn't get the same viewership as you did for 'monster fish.' So they went with 'monster fish,' which is fine.



18:03



Back to lethops, they only found dead specimens of them, until one afternoon, a fisherman brought one up that was on its last legs, so to speak. He was still gasping for breath. He was minutes from dying. And so as the scientists were looking at this fish, they noticed these air bubbles forming just below the surface of the skin. They watched these air bubbles form as he died.


What's really interesting about that is that's a characteristic of what scuba divers go through called fatal decompression syndrome or 'the bends.' Scuba divers are at great depth. As they're surfacing, they have to stop every so many feet, at least 15 feet from the surface, to allow time to off-gas. The gas in their blood has to stabilize. Should they rise to the surface too quickly, they don't have time to stabilize and air pockets will form in their blood and their blood will pretty much turn into foam,and it's fatal.  That’s what decompression chambers are for.



19:11



So that's exactly what's happening to these fish. These fish are used to living at extreme depths and there's some physical structure in the River that's propelling the fish to the surface faster than they're able to stabilize, and they meet their death. So another part of our job was to figure out what was causing these fish to plummet in the upward direction.


This is another shot. It gives you a size perspective of the fish we were looking at. I'll move away from geology and biology a little bit and get into a field that I'm a little more familiar with,and this is where my field of science came into play. It was within that field verification in hydroacoustic measurements.



20:00



We had these model predictions that showed us what they expected the depths of the Congo River to be and how fast they expected the water to be, but they wanted somebody on the ground to actually give them ground-truth information and say, "Yes, this works" or "This does not work," and then try to relate those features of the River to why the fish species were so isolated. What was causing them to depopulate?


We had two teams that were kind of working on that project. The first was a seven-man kayak team. They were charged with running an 85-mile stretch that had never before been navigated successfully. They were also going to take National Geographic photography and videography down this reach that had never been seen by anyone other than the locals. And we were going to try to rig up some instrumentation on their boats to see if we could get some really neat data sets from that part of the River. We'll talk more about those.


The second one was kind of a two-man hydrology team. This is where I came into play. That team was myself and Dr. Ned Gardner from the Museum. He's a geographer.



21:09



And our primary function was like three-dimensional velocity data and telemetry data. We wanted a three-dimensional map that showed why and how the bed was so irregular and then how the water was passing over that irregular bed, what it was doing to the velocities, how it was creating this turbulence. That instrument--you're welcome to come up and look at it after the fact. That orange boat sitting on the table is the instrument we used. That's an acoustic doppler current profiler. It's a hydroacoustic instrument that sends acoustic pulses in the water column and is able to show you in real time what the velocities are and what the bed looks like.


We'll talk a little bit more about the kayak team. If you look on this picture, and see these black circles that just showed up, those are the first two kayakers on their way down to the lower Congo River.



22:03



They're seven guys and they had to draw straws to see who was going to get to claim the fame, to be the first two to navigate the upper rapids. And if you look at the size of their helmets in comparison to the size of those waves, it kind of puts the whole thing in perspective. But they did it successfully.


Another cool part about this day was we were really close to a village, and the village--just the fact that we were white was quite an attention-getter. They came out to see what all these crazy white folks were doing on the banks of their mighty river. And then to see these little plastic boats, they really came out to see how foolish we were going to be to put those things in the water.(Laughter) So these guys put these first two boats in and did a shoot of...it was probably two miles, just as a test to make sure that they were as capable as they thought they were.


And the whole village is standing on the banks of the river. And when they saw those guys pop up on the downstream end and were paddling over to the shore, they just erupted in this great applause and cheering, and it was just an awesome experience to see the looks on those people's faces and see that somebody had come through the river.



23:13



This is the first little National Geographic clip. This comes straight out of the Explorer episode... This is talking about our kayak team.. This runs for about two minutes. Let me know if it's not loud enough. I'll play back and I'll turn up the volume.


[Clip]


Announcer: The Lower Congo River's rapids and whirlpools make much of its length inaccessible, but Melanie has brought a secret weapon. A team of world-class kayakers, led by one of National Geographic Adventure Magazine's Adventurers of the Year, Trip Jennings. They will brave the Lower Congo's raging waters and collect depth and hydrology data in places no one else can go. All while attempting an historic first: a four-day, 85-mile journey down the Lower Congo, in kayaks.



24:07



Using kayaks to map a river is an experiment in itself. Charged with retrofitting them are geographer Ned Gardner and John Shelton of the U.S. Geological Survey.


Speaker 1: We are investing something,.  These sediment  instruments, they weren't designed to be put together in this way, on this platform, in this confined space.


Announcer:  There fitting Trips’ kayak with scientific instruments: GPS to chart position, an echo sounder for measuring depth, and the data logger to store all of this information. These tools will provide the first glimpse of what lies beneath the waves of the Congo River.


But working in this environment with instruments this sensitive is a gamble. That's why they chose the Kensuko rapids for the test run, one of the roughest stretches of white water on Earth.



25:07



Speaker 2: Look at that thing explode! Look at that!


Announcer: The water collected by the vast Congo basin drains into this bottom lake. The flow is more than a million cubic feet per second. Enough water to fill over 800 Olympic-size swimming pools every 60 seconds. If the equipment survives here, it's likely to make it through the 85-mile journey ahead.


[End Clip]


John Shelton: You heard what he said last. He said, "If the equipment survives here," it's likely to make history. That's a little bit of foreshadowing. There's a good story coming up.


This is a close-up of that kayak. The kayak on the top, you can see the white globe is GPS. That's enabling us to keep submeter accuracy as far as location. They wanted to know the exact location of that kayak so they could reference the depth data that was also collecting.



26:15



The depth data we were getting from this grey box, this is an echo sounder, and the transducer for the echo sounder is actually mounted inside the hole, so the transducer's sending the signal down in every second to get a depth reading. The depth reading would be geo-referenced to the yellow black box GPS processor. Then it's all being fed into the data logger to record all this information.


In the bottom picture you can also see the orange kayak also had a camera up here, pretty large camera mounted to the front of it. And then his partner has a camera mounted to his helmet. Also in the back of the kayak we had water quality sampling supplies.



27:00



At first it doesn't seem like any great deal, but you have to also think that all this instrumentation requires some substantial amount of battery power. Water quality samples take up quite a bit of space. We're adding a lot of weight to these kayaks where weight is not a good thing. The boats were considerably lower in the water than the kayakers were comfortable with. We were also--with all the equipment taking up valuable space that they were going to need for supplies as far as tents and sleeping bags and food.


But this group of guys was incredibly gung-ho and supportive of the project. They actually work,they have their own organization, I guess, where their kind of scope is to travel in these international rivers and kind of bring the importance of water resources to the forefront on a global scale. So they were really excited about being able to help us with this and we were very grateful to have their assistance.



28:04



If you look, they put in just below Kinshasa, in this area, the 85-mile stretch travels along that red line and  ends here. This is Pioka. The little village of Pioka just above Luozi.


The trip was scheduled to take four days. They were going to go... They were, again, recording depth all along the way. They were also collecting water quality samples at every tributary that came into the Congo. They were taking a good deal of video for National Geographic.


And along the way, on the morning of the third day, they woke up to a military force pointing AK-47s and shotguns at their heads. Not a good way to wake up especially in the Congo.



29:00



To make matters worse, of course the whole kayak team was English-speaking and the military was French-speaking, so there was not a whole lot of negotiation going on. They did have government papers, but at first the military was not interested at all. They kept them all liad down, commenced to riffling through all their belongings and took whatever they wanted to take.


At some point, I think the whole ordeal probably lasted maybe an hour. They asked the boys to stand up and they were trying to march them into the woods. At that point the kayakers said, "You know, this is not good. We're not going to walk into the woods. We've shown you our papers." And so they turned around and walked the opposite direction and just kind of crossed their fingers that everything was going to be OK. There was no confrontation. They got their boats and paddled away. And they made the trip in three days instead of four days. They weren't about to stop again. [Laughter]



30:00



We met them in Pioka and they were visibly shaken, and rightfully so. It was a great reunion we were happy to see them.,and we were also very excited to see all the data that they've collected on this never-before-seen portion of the river. I will say that this portion of the river was previously attempted. I think it was in the '80s by another kayak team, and that kayak team put in at the same place and they were never seen again. They didn't make it.


So the whole kayak instrumentation project was kind of one of my tasks. I had instrumented this boat and put all the equipment together. I had planned how it was all going to work so flawlessly. And we started pulling data cards to look at all this data and had absolutely none. We hadn't collected the first piece of information on that 85-mile trek. And you talked about letting the wind out of your sails,  that was a hard pill to swallow.



31:04



We looked, I looked at everything I could possibly think of to figure out what had failed and we had no idea. So I was pretty beaten. but the kayak guys, being the gung-ho crowd that they are, they said, "Look, we're only in the Congo once. We still got a few days. Let's do it again!"


[Laughter]


So they did it twice.


[Laughter]


Yeah. Not this boy.


[Laughter]


They loaded up all their kayaks in the jeep. They made the trip back to Kinshasa which in itself takes another day. It's a day down a mud trail, pretty much, to get back to the city. We rewired the instrumentation. We came up with some other ways that we thought might improve the process. They put in--the second time they made the trip in two days.


[Laughter]


They paddled pretty ferociously. And when they did camp, they camped on the island in the middle of the river, with no hopes of meeting any unwanted guests.



32:08



So they made it. We saw them on the second day. We pulled the data cards. We had a beautiful data set of single-line telemetry down the center line of the Congo River for 85 miles. It was part of that data set that we discovered a reach of, I think it was about a quarter of a mile that had depths in excess of 700 feet. We were just blown away by depths of 700 feet.


We looked it up after the fact to see if we could find any documentation on the deepest river in the world, and the only semi reliable facts that we could find was from NASA, they documented the Yangtze in China at about 450 feet. So we smoked them and were pretty tickled. 700 feet on the Upper Congo and a great data set.



33:01



We'll move away from the kayakers and get to John and Ned's excellent adventure. This is Ned on the boat here. That's Dr. Gardner from the American Museum of Natural History. This is at Luozi. We had two boats primarily that we were working out of. They're pirouge. The pirouge in this case is a carved wooden canoe. This canoe here, it's actually about 40 feet long. It's carved out of a single tree trunk. Forty feet long and it's probably somewhere around three feet wide, I guess.


And if you look on the back it's got a--on this particular day, it has a 25 horsepower motor on it. So we have a 25-horsepower motor powering a 40-foot wooden boat in the second biggest river in the world.


[Laughter]


They told me this upfront and I honestly thought they were kidding.I think if I had known that beforehand I might've rethought the whole trip. But we'd get to some of the water if this boat went through.



34:12



This is that same boat on the left. We had the red one, which was the big one, probably 40 feet, and then the blue one, which was considerably smaller in every aspect. It was--I'm not exactly sure, it was probably in the 25-foot range. It was also considerably older, the wood over the years has warped, so it wasn't exactly straight. It was kind of curved and cockeyed. I think it had a 15 horse on the back.


This is another clip that kind of explains what we did with our data collection. So I'll let this one run.


[Clip]


Announcer: John and Ned set out to document the barriers that are keeping Melanie’s  fish populations apart. They brought the right machine to do it.



35:01



Meet the Acoustic Doppler Current Profiler or ADCP for short. On board this miniature trimaran are four acoustic transducers. When activated, they fire acoustic pulses through the water to chart the floor of the river and record the speed and direction the water moves.


Speaker 1: They're marking it not like how we see it. What they're doing is they're looking at it like a fish. They're looking at depth, velocity, temperature, conductivity, PH., dissolved  oxygen; how much oxygen  in the water. That's very, very critical for  fish.


[End Clip]


John Shelton: So this was our first data set that we collected with that instrument on the table. This was our first discharge measurement of the Lower Congo River. Not just our first but actually 'the' first discharge measurement on the Lower Congo River.



36:04



We measured about 1.3 million CFS and that to a --I'm a stream gauger at heart, that's what I do. And to me this was--they make fun of me on the boat actually because when I crossed the million CFS mark, I was actually taking pictures of my computer screen.


[Laughter]


The guys there showed them I've just joined the million CFS club. It's like the gold feather in my cap. In the U.S. we only see flows like that on the Lower Mississippi probably.


We did this in about 22 minutes. A single pass in 22 minutes. The river at Luozi where we did this first pass was about 1.3 miles wide, so an incredible quantity of water flowing through a huge [inaudible]. What we're looking at in this plot, this is direct output from the software. This is like a slice of the river. So you can see the black line is the bed. So you can see where it's shallow on the bank and then it gets deeper towards the center.



37:01



And then the color codes are velocity magnitudes, so you're looking at how fast the water is in those different areas. You can see the reds and the yellows will be the fastest flows over towards the right hand side.


But what the Ichthyology people were incredibly excited about was this division where you have the fast flows and then the purples are incredibly slow flows. And there is no mixing. It's just the straight line division there where if you think about it from the aspect of a fish who's living in these calm, slow flows, where this fish to accidentally move over, for some reason be pushed just a foot or two in the wrong direction, he suddenly caught in these flows that are 20 times faster than what he's used to living in and he's on a jet on the way to the ocean.


So they were excited to see the capabilities of this instrument. They were hoping that it would be applicable to the other areas that we were looking at to help define why these fish populations were so divided.



38:13



We went from Luozi upstream to Pioka. Pioka is the little community where we met the kayak team on the end of their second journey. And I'll stop here and talk about this gentleman. This is Mr. Durak. And you can see on our trip that unfortunately he was in the little blue boat, the small boat. It's about wide enough to wedge your hips in. There's not a whole lot of wiggle room there. It's crooked.


And the journey from Luozi to Pioka is where we saw our first turbulence, where I first saw my first turbulence ever in the whirlpools and boils that were just magnificent. We had four people in the boat. We had a producer for National Geographic sitting in the front, he was in the front of the boat facing backwards.



39:05



And then my partner Ned was in front of me, and then it was me. Then we had Durak, who  was our boat driver. Ned, the character that he is, he had his banjo out. Ned's playing his banjo as we're riding in the canoe up the Congo River. It's a great picture. He's looking off towards the left-hand side, opposite direction.


The right-hand side is magnificent. Mind-blowing whirlpool opens up. I mean, just a black hole into the middle of the river goes down into darkness. And I've never seen anything like that. You certainly don't have them in South Carolina. [Laughter] So in my excitement, I yelled for Ned and for the gentleman in the front, and I pointed at the whirlpool. Well, Mr. Durak, who doesn't understand English, thought I wanted a closer look.


[Laughter]


And so he took the tiller handle of the boat and cut the boat hard right.



40:01



And let me tell you, a 25-foot wooden canoe with an outboard motor on it doesn't spin on a dime. It more tends to kind of roll. And so it started rolling, our equipment's going all over the place, we're grabbing the sides of the boat for dear life. And the boat rights itself, we're all OK, our hearts start beating again, lungs start functioning and breath this great sigh of relief. And Ned said, "You know, that was really close." And the National Geographic guy said, "Yeah, it was too close. We lost our boat driver."


So we turned around and Durak is in the great whirlpool. His arms were flairing, his eyes were as big as saucers. And we're putten up the Congo River in a uncontrolled boat. So it's quite an experience. I jumped up, ran to the back of the boat, grabbed hold of the motor, and very gently turned the boat back around to go back for Durak. They grabbed him, pulled him back in the boat.



41:00



You'll notice this picture was taken after his rescue because now he's wearing a life jacket.


[Laughter]


Yeah. He did not lose the life jacket for the rest of the trip,so Ned laughed and did not ride with Durak for the rest of the trip.


[Laughter]


He chose to stay in the bigger boat. Well, yeah. I also learned--it was also a joke, too, Ned always told me, he says, "from now on  John, when you see something really cool, keep your hands in your pockets."


[Laughter]


"Don't point."


This is our camp at Pioka. If you can remember, one of the earlier slides kind of showed the profile of the Congo River. You had those two extreme drops in elevation. The first is here. This is part of the Livingston Falls chain. When we're motoring up the Congo River, you just see this white wall up in the distance.


I looked at it for the longest time trying to figure out what that white wall was. Well, it’s  a waterfall! There's a waterfall in the Congo River that makes upstream navigation impossible. But that's what we're looking at here.



42:07



This is our camp at Pioka. The lower photo, this is my tent. This is laundry day, obviously., we cleaned our clothes in the river and then hang them on your tent to dry.


This is all our equipment. I took with me probably close to $175,000 worth of equipment. Paranoia doesn't even begin to describe how I felt about having that kind of equipment. So every night I would take a rope and tie every piece of equipment together and then run the rope inside my tent and tie it to my shoes. So if they stole the equipment they'd, well, they'd probably take my tennis shoes as well.


[Laughter]


At least I'd know if it was going somewhere. We had no problems. We didn't lose anything, except the solar panel, actually. We lost one of our charging stationschargers space, but that was no biggie.


The upper picture shows, one afternoon we had a gentleman from the military who came down from the hills and everybody was a little leery.



43:07



This was after our kayakers that had their little run-in, so seeing somebody walking down with an AK-47 strapped to their back made us a little uncomfortable. But he was actually just curious. He wanted to know what we were doing and checked out the laptops and see the data processing. It was very friendly..


While we were there, we had several processing issues. This is something that I've actually never even thought about stateside. And of course we're in the Congo for just better than 30 days and we're using all this scientific instrumentation and it's all electronic. It requires some source of power and we had no electricity at all. So we had to figure out on the forefront how we were going to keep this power.


This picture--this black sheet is a big solar panel that we were able to use. It was a flexible, collapsible solar panel. So every spare minute  we had at daylight, we're connecting as many batteries as we can to keep everything charged.



44:10



When we did have access to vehicles, I'd strap all the batteries I could to the alternator and try to charge that way without blowing anything up.


And then on top of power issues, of course we had bug problems. This is... I have to say this was only one day. I went in really worried about the mosquitoes and how that was going to be a problem. And actually we were there in the dry season, so mosquitoes weren't a problem at all. But this one day, these were probably mayflies. The mayflies came out in full force and pretty much blacked out the sun.


That night, we were trying to do some processing and of course having  the lights and the computer screen on, it was nothing but a magnet, so they just swarmed in on the computer, and getting bugs everywhere you were. But next day, all gone and no problems.



45:06



So now we'll travel from Pioka all the way down to Bulu. You can see the big red boat here, it's pretty weighted down. We've already picked up the kayak team, so all the kayak team's on there as well as the Ichthyology Department from the Museum. Were heading downstream to Bulu. Bulu is the location of the white fish, the depth-dweller, the Lamprologus lethops. So that's one of the areas that we're going to do some pretty intensive studying to see what we can find, especially in relation to that fish.


This was our set-up. You can see Ned standing here. This staff in his left hand, is actually a metal pole that's on the end of it has an echo sounder transducer, so we're collecting depth data on the way.



46:01



That staff has a--there's a rope for stability. There's a rope tied across the hole of the boat and it goes around and wraps around the bottom of the boat. You get to hold them to it. It's not the most stable platform, but you do what you can.


The orange ADCP is up on the right-hand side. Again, we're connected with differential GPS. We're trying to charge as we go, so we had a solar panel in the boat to keep everything powered. We had water quality sampling equipment in the back. And then the brains of the operation and all centered everything is coming into the laptop down behind Ned.


This is where I start showing some of the results. What is the deepest river? We were quite certain that the kayakers, with their 700-foot depth, document each river in the world. Around Bulu, you can see we got depths greater than 500 feet.



47:02



What's interesting here is the ADCP is a four-beam instrument. You had four beams that are 20 degrees off the axis. So the beams are going down and creating a relatively large footprint by the time they hit the bottom. But you can see those four beams are seeing incredibly variable depths. We're varying anywhere from 330 feet to 512 feet, which kind of helps define that irregular area at the bottom, that real rough structure we're seeing. The great chimneys that are rising up off the bed and the great cliffs that we're also seeing.


In this particular plot, we have two references. One is the ADCP itself and the other's the low echo sounder. The depths were so variable that the echo sounder was falling apart, that's why we have these flat line areas here. It just wasn't as functional as we were hoping.


Velocity distribution we learned. I'll try to explain this the best I can. This, again, is that cross-sectional plot where we got a slice of the River and were looking at the velocity from side to side and from top to bottom.



48:08



The top plot, if you look at the yellow circle is up-velocities. So we're only looking at that component of the water that's going directly towards the surface. Positive would be towards the surface, negative would be towards the bed. And you can see these really identifiable blue and purple marks. The blue and purple shows on the scale as negative up-velocities. That would be a whirlpool. And that's somewhere around... looks like five feet a second.


But what's cool is you get these cyclic [inaudible] where you have the whirlpools and they'll kind of disappear and then immediately following you have these boils that will erupt and break the water surface by sometimes as much as three feet. They’ll  be 30 feet in diameter and three feet high and all of a  sudden it will just explode from a relatively calm water surface. And you're really expecting something to come up there, a submarine or Nessie.


[Laughter]


But it's amazing.



49:08



The bottom plot is what you would expect as far as downstream velocity. What's the speed of the river flowing in the downstream direction? You can see in this particular plot we also had another dead water area. We have relatively low velocities on the left bank. But the cool part about this particular section is the red circles. And these red circles are extreme velocities that are depths of probably 120 feet.


So a typical river hydraulics we expect the fastest flows to be near the surface, probably towards the center of the channel. In the Congo, due to the irregular bed surface, there's no telling where the extreme velocities are going to be. In this case, they're 120 feet deep and they're just like tunnels or jets that are flowing down the middle of the River.



50:04



Again, it kind of makes you think what the fish around it are going to do when they happen to hit that wrong spot. You can see they're kind of isolated. It would be really hard to predict where these jets are going to be.


This is another velocity distribution plot. This one you have to kind of think in a different way. We're no longer going from one bank to the other and just getting a single slice across the River. We actually started this one accidentally and then we saw what kind of data we were getting and we thought, hey wait, that's pretty incredible. Let's keep doing this.'


We started at the center of the Congo and went for just over a mile straight down the middle of the River. So this is just a one-mile stretch straight down the center. So in the U.S., in most of our rivers, we would expect to see just a relatively stable depth. It stays about the same depth all the way down because that's going to be the deepest part of the river.



51:01



In the Congo, that's not true at all. It's, again, we're looking at that really irregular nature, and that's probably due to the fact that it's relatively young and it hasn't had the time to erode like we would expect. Also, the hard rock that it's made of is very resistant.


So when we start, we're looking at depths of about 150 feet. We go several hundred yards and you can see we get from 150 feet to near 20 feet. The bed comes up and then it's only 20 feet deep. This bed, a large mound,or mountains or even classified as  chimneys, I guess, where you have just this big column in the center of the River.


So you have tributaries on either side of it, but again we're in the center of the channel. Where it gets really interesting is after the mound, you get this extreme depth and then you start having these features that look like ramps. And you can see what affects the ramps have on the velocity. As the bed elevation increases where the River gets shallower, you're trying to push that same quantity of water through a smaller area. So the water has to accelerate.



52:07



So that’s shown in these red contour areas where you have velocity acceleration. And then as soon as it gets deeper again it slows back down. And then you get another ramp and the water has to accelerate to go a little further so that is creating incredible turbulence not only in depth but also at the surface.


In the bottom …, you can see that same effect. Now we're looking at up-velocities. We're not looking at downstream velocities, but we're looking at what that effect is in either going straight up or straight down. And these are really interesting in the fact that they would do exactly what you would expect them to do. When the water comes across the ramp, it gives light green colors, which is referenced to a vertical velocity or a positive vertical velocity.


So in these areas you're just above the ramps are the areas that we're seeing these huge boils, these big eruptions where we document that. On the downstream side of the boil, you can see the purple colors. The purple colors represent the negative velocities, so immediately after the eruption or after the boil, you get the whirlpools. You get these big 'suck holes' that are created on the downstream side where that water's funneling back down, being sucked back towards the bed to try to take up that extra area.



53:21



This is a--I call it "The Turbulence". It's like the title of a bad B-movie. But we're in this area that just has such extreme turbulence. I grabbed my little digital camera that has a video function on it and I videoed some of this to try to share with you.


I'll say this beforehand on this one. You can hear my voice pretty strong in this video. I'm probably near-tears. And I'm kind of laughing, and I'm not laughing because I was having fun. I was laughing because I was scared out of my gourd. It's like when you're a child or you have children and you take them to a haunted house, and they're so scared but they don't know if they're supposed to cry or scream or what, so you get this real kind of trembly laugh going on because you're so unsure. "What's that..." Exactly what I'm doing here.



54:10



It's--so if we can get this to work.


[Clip]   (Inaudible)


 


Speaker 1: Holy!


Speaker 2: Eww! Get out of here!


Speaker 1: Ned!


John Shelton: Ned is there behind the boat and is now trembling 30 feet in diameter.


Speaker 2: What? Oh my God! What did you see on that?


John Shelton: Boys got to laugh.


Speaker 1: We got it.


Speaker 2: Yeah?


Speaker 1: Yeah.


Speaker 2: I could see. Downwelling?


John Shelton: Downwelling at 100 feet, upwelling at 200 hundred feet.



55:02



Speaker 3: Don't fall! Wow! Incredible!


Speaker 2: Oh my God.


John Shelton: They're looking a bit shallow.


Speaker 1: Watch out!


John Shelton: It's 300 feet deep.


[End Clip]



56:22



John Shelton: The way the water looked, it was really deceiving for me. I don't know if you heard what I said but...the way the water surface broke, can you see it? It looked almost like sheet flow where you have these flows over relatively shallow areas or near-surface rock formations. And it wasn't the case at all we were seeing. In that particular area there were depths of greater than 300 feet, but because of the irregular nature of the bottom, it was in such velocities going over such a rough bottom and it was creating a turbulence that was coming all the way up to 300 feet of depth.


Finishing up. Where do we go from here?



57:00



We had unbelievable amount of data collection while we were there. We collected some just really incredible data sets. We've done a lot of processing. We still have a lot to do. We had to figure out exactly what we're looking at. We want to relate what we collected with the acoustic instrumentation and look at that hydraulic data and see how it actually relates to the fish populations that the Museum was looking at. See what kinds of relationships we can draw there.


The data is a lot of fun to work with and look at. We're trying to figure out the best ways we can to present that to make it a useful tool. So we're hoping to do animations and fact sheets and then of course the National Geographic Explorer episode. That episode came out in February and it's done very well. It's actually coming on again in July. It will be on I think four times in July. It's called "Monster Fish in the Congo".



58:01



As far as visualization projects, we've had several hydrologists across the nation who wanted copies of the data set to work with. And we have one in particular in the Illinois whos taken it and developed some incredible graphics. I'll share you just a few quick examples of that before we finish up.


All the water quality samples were processed and analyzed. We have that information back. We're just waiting for our water quality people to kind of dig into it and tell us exactly what they've got. Then we're actually hoping to have some future projects as well. There's a lot of interest in the work we did and meeting many organizations and several different national governments who were really curious about all we were able to find.


But we’ll look at some of that work, some of visualization tools. This is--his name is Dr. Ryan Jackson from the Illinois Water Science Center. This map, it just kind of put it in perspective.



59:01



This is around Bulu. So we camped up here. Around the number1 was our camp. The pool is the area that the fishermen took us to and said, "This is where we find the most Lamprologus lethops. The white blind fish." They said, "This is where we find most of those dead fish, somewhere in this area."


So I was really pleased that he focused so much on this data set because now when we've got ground-truth information that corresponds to lethops so we are able  to look at what we were speculating is actually correct. You can see the pool elevation is close to 500 feet, so we have a pretty extreme depth. So right off the bat we're saying, "OK, good, that's home of the depth dweller, that makes sense."


We'll zoom in on this particular area and look at some of the graphics that he's created around that pool where we think lethops is. This first graphic is a pethimetry map.



60:00



We’re looking now at how the bed is laid out in that particular area. You can see upstream of where lethops is found.


It’s relatively flat, still pretty deep, somewhere in the 200 - 250 feet range. But then, in this area, you can see we go from dark browns to light browns and yellow, greens and all the way to light blue in a relatively short amount of time. It’s like a plunge pool or an area at the bottom of the waterfall. It’s just really deep,  really quick.


We have this light blue area, which is the deepest area somewhere in the 500 plus foot range. So now, we see the hole and it has big potential or where we expect lethops, and then we are going to change that and look at up velocities.


So if you remember looking back – here’s the little cove, it, comes straight down the cove towards the deep spots is right in the middles and now we’re looking at up velocities.



61:05



It comes straight down again so and we’re looking somewhere right in here as the deep area. So this color contour is looking at verticle velocities. It’s looking at that flow that’s going towards the surface.


So you can see, in the deep area, we have very little upward flows in the greens and yellows. So it’s a relatively stable condition. [Laughter] Sure. Can you hear me OKwithout  it?{Microphone)


Audience: Yes.


John Shelton: Let’s go. I’ve only got like two minutes. So in this area of the deep hole, we have a very little upwelling. The blues are actually a little bit of downwelling, so they have a little bit of down pressure that can actually help keep them over there.



62:09



But the really interesting part is this red flum just off the edge of where the deep hole is. And that red flum is close to three feet per second in the upward direction.


So if those fish just happen to move from this little area of downwelling suddenly this acts like a sonic elevator directly to the surface, which really corresponds to what we thought was happening. We got an area of extreme upwelling right beside the deep hole. If the fish are in the wrong place at the wrong time, they get propelled to the service and failed decompression takes place.


That’s another cross-sectional plot, kind of looking at how that would also work, see the color codes represent downstream velocities. So we have the reds that are pretty fast in the downstream direction and they are right next to another area of low velocities.



63:05



That arrow that are embedded in this graphic in the bigger gray areas are secondary velocities. So you can actually see the little arrows in this area where you get the slow velocities that you have and a secondary current. It’s actually pushing water underneath into the fast velocity.


So we get this area then once again, wrong place, wrong time you get caught the wrong velocity profile. That’s it, this is just kind of a montage of pictures I thought were pretty cool that didn't belong anywhere else in the presentation [Laughter]. If you have any questions, I’ll be happy to answer those. Yes, sir.


[Applause]



64:04



Male Speaker: Your interest in translation on a most unusual content, but how did you, your organization justify going to Africa, conducting the study you did there? Why did you get the taxpayers to send you over there?


[Laughter]


John Shelton: The good news is, one, the USGS is recognized  as a world leader in this particular form of instrumentation. So they were looking for someone who had the expertise to do it. Good news for you is, you didn’t fund it. The American Museum of Natural History paid my salary and National Geographic paid for my travel.





Details

Title: USGS Public Lecture Series: A Field Trip to the Congo--Hydroacoustic measurements in "the river that swallows all rivers."

Description:

Imagine yourself in central Africa, in a dugout canoe crossing the lower Congo Rive''s rapids and whirlpools. USGS scientist John Shelton found himself there this past summer, measuring places where the waters reached a depth of over 700 feet. His measurements indicate that the Congo River is perhaps the deepest river in the world! This discovery was made during data collection to describe the River's conditions and understand its extraordinarily diverse richness of fish species. In this effort, Shelton worked with a team of scientists from the American Museum of Natural History.

Transcript will be available soon

Location: Reston, VA, USA

Date Taken: 6/16/2009

Length: 0:00

Video Producer: U.S. Geological Survey


Note: This video has been released into the public domain by the U.S. Geological Survey for use in its entirety. Some videos may contain pieces of copyrighted material. If you wish to use a portion of the video for any purpose, other than for resharing/reposting the video in its entirety, please contact the Video Producer/Videographer listed with this video. Please refer to the USGS Copyright section for how to credit this video.

Source:

For more information on this topic visit:
The American Museum of Natural History
National Geographic--Monster Fish of the Congo

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