Why Rivers Move

The basics of fluvial geomorphology (the science behind the shape of rivers)
Watch Part 2 of this series: • Why Engineers Can't Co...
Errata: At 11:54, the slope equation is inverted.
We’ve teamed up with @emriver , a company that makes physical river models called stream tables, to create a two-part series on the science and engineering behind why river channels shift and meander and what tools engineers use to manage the process.
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Practical Engineering is a KZbin channel about infrastructure and the human-made world around us. It is hosted, written, and produced by Grady Hillhouse. We have new videos posted regularly, so please subscribe for updates. If you enjoyed the video, hit that ‘like’ button, give us a comment, or watch another of our videos!
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DISCLAIMER
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This is not engineering advice. Everything here is for informational and entertainment purposes only. Contact an engineer licensed to practice in your area if you need professional advice or services. All non-licensed clips used for fair use commentary, criticism, and educational purposes.
SPECIAL THANKS
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Thanks to Emriver for hosting our crew. Check them out at Emriver.com!
This video is sponsored by Keysight.
Stock video and imagery provided by Getty Images and Shutterstock.
Music by Epidemic Sound: epidemicsound.com/creator
Tonic and Energy by Elexive is licensed under a Creative Commons Attribution License
Source: • Elexive - Tonic and En...
Producer/Writer/Host: Grady Hillhouse
Editor: Wesley Crump
Production Assistant: Josh Lorenz
Script Editor: Ralph Crewe
Background Painting: Josh Welker
Graphics: Nebula Studios

[@PracticalEngineeringChannel]

📟Step up your electronics skills and win free gear from Keysight! Sign up here: www.keysight.com/us/en/events/keysight-world/live-from-the-lab-practicalengineering.html 🌊Huge thanks to Emriver for having me at their headquarters. Make sure you subscribe so you don't miss the second video in the series!

[@wagglebutt]

I'm sorry to report that your slope equation is inverted. 11:54

[@In_Rem]

Can you make a scale model of the Nile from up river where the Blue and White Nile conjoin to down river to Dongola. don't forget to scale in the 8 inches per mile squared to account for the earth sphere's curvature drop and explain how the river is able to flow both up hill and down hill through this region.

[@dm3on]

is there computer simulation for rivers movement ? (all I could think of while watching video, how I can simulate this)

[@In_Rem]

@@dm3on good luck with a computer program, earth is an observable stationary level plane.

[@kaboom-zf2bl]

Victor Schauberger ... Copy and comprehend nature ... great video and it covers whay waters shift and how to control them from back in 1910 era ...

[@SnappyWasHere]

I am beginning to think the main reason you do KZbin is to satisfy your model building hobby. Another great display!

[@desupernoodle]

You gotta keep secret or his wife will figure out!

[@JacobGrippenMusic]

@@desupernoodle eh, if he’s making money, and teaching folks, why should she care if he’s having a good time? 😉🙂

[@ammonjohnson5592]

@@JacobGrippenMusic It depends on how much money is being made. Is there enough money to offset the model building costs?

[@JacobGrippenMusic]

@@ammonjohnson5592 of course. I still need to buy his book, soon hopefully.

[@moxxy3565]

Also since his channel is monetized he can write his models off on his taxes as a business expense 😊

[@sean..L]

The fact that there is a company that specializes in creating highly detailed models of rivers is so cool.

[@emriver]

100% agree! Mind if we quote you on that? 😊Happy Pi Day!

[@ABANDONEDCHANNEL68]

​@@emriver Nice Models!

[@supercharged5-39]

@@emriver woah its them

[@AWSVids]

I'm currently working for one that builds models even bigger than the one in this video. They test designs of bridges and dams, etc. Huge warehouse sized models with massive tanks of water. They're pretty cool to see in action. This is the best video I could find of one online, but I've worked on ones even bigger: kzbin.info/www/bejne/bXXQgHl3aayod80

[@JohnVanderbeck]

@@emriver These tables are so memorizing I want one in my home!

[@gordonallen7334]

As a fluvial geomorphologist I wish this video was around 10 years ago so I could sit every city that we went to do a project in and make them watch it! The introductory course 😁. A couple other folks that have really made big strides in predicting river movements are Luna Leopold and Dave Rosgen. Worth looking into their work as well!

[@referencefool6525]

🔎📚usbr.gov/tsc/techreferences/mands/mands-pdfs/Erosion%20and%20Sedimentation%20Manual.pdf

[@TheGarratc]

I'm taking Rosgen's level 3 course in Wyoming later this year

[@emriver]

"The river is the carpenter of its own edifice." - Luna Leopold 😉

[@gordonallen7334]

@@emriver We have a lot to learn from him!

[@KingCouilles]

Rosgen is a more controversial figure as his approach seems to be centered on form rather than process. See Simon et al. 2007 for an in depth critical review of his approach to stream restoration. However I did hear that the higher level courses provide more nuance and better consideration of processes. I still think that the misinterpretation and widespread adoption of his introductory material can lead to bad projects which can tarnish our discipline in the long run.

[@jasonpatterson9821]

Thank you for including high quality subtitles with your videos. Automated subtitles are getting better all the time, but names, technical terms, and the like are often incorrect and the pacing can be terrible. You are providing a useful service not only to people with hearing disabilities (me) but also to people who can't watch with full volume sound for a variety of reasons. Again, thank you - your thoughtfulness is genuinely appreciated.

[@rogerhorky7258]

i teach college history and refer to the shifting of river channels in my lectures about the transportation revolution in US history. The "wedding cake" steamboat (the one we associate with Mark Twain) was designed specifically to meet the challenges of the constantly-shifting rivers between the Appalachians and Rockies--the Ohio, Mississippi, Missouri, and all the rest. Their most important feature was a VERY shallow draft--two, three feet--to avoid the sandbars, snags, and snakeheads (submerged trees) of the river channels. I'll be citing this video in my classes.

[@Swampratatta]

im gonna take your class

[@eriklarson9137]

@@Swampratatta $10.00 says you don't do it.

[@jameshisself9324]

@@eriklarson9137 Since you can't prove it either way, he did do it and I'm a witness. You owe him $10.00. @Swampratatta I'll take my cut now.

[@salvadorvega9834]

W professor

[@lizj5740]

I hope you tell your students about Mark Twain's Life on the Mississippi, a memoir of Twain's time as a riverboat pilot.

[@danrobidoux]

This is an example of a perfect KZbin video, and one that makes the platform worth using. A subject that, although I'd never go out of my way to learn about it on my own, is undeniably fascinating when explained by someone who is both knowledgeable and passionate. I learned so much in the span of 15 minutes, and I'll never look at a river the same way again as a result. What's not to love about that? 🌊

[@halfbit]

Um, any low lying area in the vicinity is a potential path. No charge.

[@DeadsTBD]

True, seeing how it work is very interesting and this experiment make me remember of a game (from dust) where you had sand and water sources and the river that were forming usually ended in delta... I never really though much about it but then explained it make sense...

[@Hillwatch]

I agree with the op. Now I feel armed with knowledge so that next time I look at a river or drainage or gully, I can understand the significance of its erosion pattern to some extent

[@erinmac4750]

Truth! That's one of the reasons I hope YT doesn't go crazy trying to compete with TikTok or other platforms that have different parameters. A couple other channels which have opened my eyes in similar ways are Pecos Hank, a storm chaser, photographer, musician & critter lover, and Just Icelandic, a quintessentially Icelandic story teller)videographer who loves his country and is learning about its volcanoes. 💜🌎🏞️🍀✌️😎

[@candaceloftus1047]

As a water resources/river engineer, well done. All the river engineers I know will tell you that playing with a stream table is one of the most fun things to do and is often the gateway to getting into this field of engineering. I know it certainly was for me.

[@WinstonSmith0824]

I'm sure you know, but just to be safe, this is a lie and a scam. (The telegram message above)

[@stefanomorandi7150]

im not an engineer nor do i work in a related field.... if i had the space i would build a stream table like this for myself, it looks so much fun to use! i bet a crafty person could make a tabletop game out of it with placing little homes and trees and stuff!

[@scbond]

@@stefanomorandi7150 placing objects in is exactly what most do with these. I used one with a load of plastic bin liners to simulate urbanisation.

[@willburkhart7430]

Thank you Grady for covering this topic! I'm a water resource/river engineer (and fluvial geomorphologist as needed) who often feels unseen in the civil engineering world. As river Restoration and fish passage become bigger parts of the industry our profession is growing rapidly and it's really exciting to see you discuss rivers and their processes! Playing with stream tables like the one here and playing with my grandparent's creek as a kid inspired me to work with rivers. Videos like yours will help to inspire the next generation of river engineers!

[@cartertran270]

One of favorite things about water is that it scales almost perfectly so you can do thing small scale and represent real world results.

[@ohioplayer-bl9em]

I used to love building damns in the creek near my house. I would spend hours finding just the right rocks to make it as water tight as possible and create big pools of water behind it. A large rainfall would destroy it overnight. A few years back the city widened the creek and poured concrete making it a smooth water channel with no wildlife anymore. Sad to see because it was beautiful and teaming with life. Various turtles, Craw Dads aka craw fish, minnows and other small fish. It dumped into the river just a mile downstream. Its now just a smooth and open water channel, no rocks or anything for the life to live in.

[@pony3284]

​@@ohioplayer-bl9emis that legal? Sounds like it would lead to A ton of issues

[@Lucius.Hercules]

watching stream tables and seeing how rivers form is quite possibly my favourite thing. everything on this channel is extremely fascinating but frankly, this is the best yet.

[@dalanoyo]

I'm sitting here trying to think how I could design one of these into a dining room table that I could watch how it changes over the years

[@jaredf6205]

@@dalanoyo an autopsy table seems to have most of the same design features, you could probably pick up a used one.

[@dcjxd]

@@jaredf6205 Mate, I just showed this video to my wife and was super excited about it and she mentioned how much I played the last level of "From Dust" just to see deltas form. Great recommendation.

[@jaredf6205]

@@dcjxd Yeah, as a kid I would play with water cascading down sand and dirt in big tree roots, I’ve just always kept an interest in it. Also check out the KZbin channel Emriver, they have years of videos using these.

[@jansalomin]

@@jaredf6205 That game needs a reboot, imagine if we had a game purely focused on water

[@adamplace1414]

If you grew up in a rural area and played outside when it rained, every trickle of water past a muddy patch became your own personal stream table. I found it fascinating then, and I still do today.

[@WinstonSmith0824]

I'm sure you know, but just to be safe, this is a lie and a scam. (The telegram message above)

[@matthewerwin4677]

My buddies and I blocked a 24' culvert and flooded an entire field for fun.

[@Lillireify]

We had gravel/muddy road leading up to our house where I grew up. I was fascinated with blocking and steering water around from puddle to puddle :) this and several other things were the reason I was studying to be a civil engineer :) I left the field in the end, but the love and admiration for engineering and other connected sciences is still there.

[@nerdwisdomyo9563]

I’ve done this, you could actually see the bottom of a hill turn into mud then a stream then a river then a lake to a bigger lake to another river and so on

[@TheTraveller20081]

Every time I find a stream flowing down a beach...

[@borghorsa1902]

My favorite past time! I used to play with water and sand on our farm for hours at a time, have witnessed mini rivers, deluges, dam formations, waterfalls, alluvial floods, mini lakes and even local animal behavior changes because of new "lakes" and "rivers" I have created. Once in the middle of a very dry summer I have created a mini puddle then forgot about it, left the water running, half hour later came back and found a colony of ants making a little trail to the water's edge. There were other bugs appearing out of the "woods" at the shore of the puddle. Dad was joking that I singlehandedly quadrupled our water bill but he never actually stopped me and actually encouraged me to study fluid dynamics 🐜🐝🐝🐝🐝

[@terracottaneemtree6697]

Congratulations! I'm sure you can use it. 😁

[@Simcitywok]

This guy is the best. He doesn’t play the KZbin clickbait game (“you’ll never believe the 3rd reason why rivers move”) and nothing is controversial or negative. What a prime individual

[@reedr7142]

I’ve made a conscious effort not to click on those anymore. Even if they end up NOT being click-bait, it’s just annoying. At least we can report them as being spam/misleading.

[@OldOneTooth]

As a kindergarten teacher for many years we made many rivers in sandpits everyday, even got water to travel under the sand and made it well up, then move the springs. One of my favorite parts of the job, so no surprises here.

[@Vinemaple]

You would never have gotten me away from that table!

[@kindlin]

Super cool kindergarten teahcer! I just did normal lame stuff like be read to, take naps, draw pictures, and every once in a while count to 10 or try and write your name.

[@glen7695]

Thanks for your service. And thanks for inspiring young minds!

[@ChemEDan]

Thanks for restoring my faith in humanity 🙂

[@mariokarter13]

An interesting experiment might be to run water through a mixture of materials (sand, sugar, salt, etc.), because sediment isn't just one thing.

[@CajunWolffe]

Grady, as an old and retired mechanical engineer, you make me wish I had taken up civil. My career involved massive machinery such as turbines, reciprocal integral gas compressors, and generators. When I graduated from engineering school, we still used slide rules, and I still have my trusty Post Versalog II. Once again, great video; keep them coming to inspire the next generation of engineers.

[@kindlin]

I have a slide rule sitting on desk that an old coworker gave me as a good luck gift for my engineer career when I was still in college. It's super nice with a leather case and everything. I know the gist of how it works, but I've never actually tried to do math with it.

[@ahndeux]

@@kindlin My co-worker gave me an abacus as a good luck gift. Now I just use it to calculate all the money I made by not being an engineer.

[@richardross7219]

40+ years ago, I was a Civil Engineering Graduate student at UCONN. I was helping Professor Jack E. Stephens with a project. We got along well. By a funny coincidence, his oldest son and I were in the same squad in the Army years before. We were talking about engineering disciplines and he said that we civil engineers have the most fun of all engineers. Now that I'm retired and look back, I agree with him. I built: roads, bridges, and buildings. IT was a challenge to design them but when the construction was done there was a huge sense of accomplishment. Take solace that mechanical engineers are usually paid better than civil engineers. I see your name and have to ask, are you from LA? My wife was from Jennings. Good Luck, Rick

[@kindlin]

@@richardross7219 I debated going into theorteical physics, or a math major, or maybe CSE, but none of them had the real world impact that Civil does. And with the structural focus (my dad was a foreman in a construction company), I can see the actual buildings and things get built that I designed the year before.

[@johanneswerner1140]

I used a slide rule when studying physics, early 2000s. Anything I cannot do with it required a computer anyways... Maths was lots of proofs, and physics was either purely using variables (plugging in the numbers was not the big deal) or lots of complicated calculations, numerical integration, numerical deq solving etc.

[@rogervaught3985]

In the 70's, the Corps of Engineers had a scale model of the Mississippi River drainage basin outside of Jackson, Mississippi. A stream table that covered covered acres! They could simulate precipitation and flow in various areas to better understand how changing precipitation from the Rockies to Pennsylvania could affect flooding and erosion. After thousands of scenarios, it was shut down. It was very interesting to walk over the model and have the project explained.

[@amberbydreamsart5467]

Over the lockdown periods of the pandemic, I took a daily walk in the woods behind my parents' neighborhood. There was a little, tucked-away, undeveloped spot where a local significant creek met a significant river of the area. This being an area that tends to get significant downpour that threatens river flooding a few times a year, it was a quite active flow spot that was maybe a food deep on your average day, but I once saw it at about six feet deep. Watching how it changed day by day for a year and a half was honestly a great way to get a sense for now non-static even a relatively healthy stream and river meeting is. When I first started walking there, relatively recently a tree had fallen over the stream, just ten feet before it met the river. Initially, it flowed fine, and the log was a great transport to some trails across the creek that were otherwise a mile away from another access point. But as the year went on, the tree started to significantly dam flow. Stagnant pools developed behind it and on the side i entered, where there was one a long, gradual sandy bank, now had become steeper with a lot of the sand washed away as the main flow transitioned from the far side of the creek to the near. Finally, after a major flood, the near side, sandy bank washed away entirely. The fallen tree and its trapped debris had fully dammed the far bank and the near was now taking the full flow of the stream, what was once a gradual cutoff was now a 3-4 foot high cliff, and you needed to get down to the bank from another spot further upstream. Then, after several months of this, another major flood came, and this time the full tree was carried off entirely! the dam broken, the stream flow returned to the far bank, and within a few months the sandy shore was already half-reformed.. now, a few years later, it's practially fully back to how it was when I first started walking there... truly a testament to the power of water flow!

[@davejoseph5615]

As a kayaker this is one phenomena that always seems puzzling whenever you see a river eating away at the edge of a farmer's field. The river has had millions of years to find an optimum path and yet it keeps moving.

[@Niskirin]

There's a powerful metaphor buried in that observation.

[@irondiver292]

I see the same thing. The increased rate is because of irrigation I am sure. Once the existing stream sides are gone, dust bowl catastrophes again.

[@yliannamarie403]

Rivers are dynamic. Our attempts to fix river boundaries is evidence that our engineers don’t understand the laws of nature.

[@cunicularium5424]

*optimal*

[@kenbrown2808]

it's because every raindrop that joins the river, and every bit of dirt the river moves changes what is "optimum"

[@Hybrid_RockCrawler]

That stream table beautifully demonstrates river delta formation. I'd love to see a cross section of it. It looked like it it came right out of my sedimentology text book.

[@MattH-wg7ou]

Sounds nerdy but Id love to flip through a sedimentology textbook for real though. Interesting stuff to me, a business major that knows nothing about it.

[@brianreddeman951]

@@MattH-wg7ou Pick up or borrow a copy of "Introducing Sedimentology" by Stuart J. Jones. That one isn't going to clobber you with hardcore equations :)

[@chrisw.8903]

This is an excellent example of of how to educate people on a complex and unfamiliar topic. Your videos are expertly crafted and written to inform and maintain interest. I am a Service and Product Designer and find so much inspiration in the way you present your content, building upon previously provided information to take the viewer to a new place of understanding. Thank you for making these videos!

[@amicaaranearum]

I like these geology-focused videos. The model river is particularly neat, with its color-coded sediment.

[@eustatic3832]

My grandad was an undergrad in Fisk's lab. I hope you can cover the Mississippi Deltarestoration, or the Texas coastal study!

[@dienelt5661]

This video scratches so many of my itches, geology, fluid dynamics, models and engineering. One of the best channels on KZbin, keep up the amazing work !

[@gustavmuller30]

I teach property law at undergraduate and postgraduate levels in South Africa. Under the broad theme of original modes to acquire ownership is the sub-theme of attaching (accesio) of immovable things to immovable things. We discuss the principles of alluvio, avulsio, islands arising in rivers and rivers changing its course. I shared this video and today's video with my class together with a time lapse of a Peruvian river changing its course between 1985 and 2020. Excellent work on the production. You have triggered a desire in me to learn more about fluvial geomorphology!

[@pony3284]

If you Inherited an island or sand bar from Mother nature, does that have to be listed on tax documents? 😅

[@matthewdockter2424]

Grady: I grew up 1 farm field away from the Upper Mississippi River in the Driftless region. River Mechanics has always been a curiosity of mine because of where I grew up. I appreciate you walking through it in the manner you walk through so many things. I look forward to your next episode. Thank you!

[@AndrewWells527]

Next time you're flying over rural areas, try to spot signs of a moving river. There are a couple creeks/rivers around Denver that are allowed to flow freely and it's cool to see those same features shown in the model. Also, Yellowstone is a great recent example of this.

[@referencefool6525]

🌋🌊What Really Happened During the Yellowstone Park Flood? kzbin.info/www/bejne/iXmco2xqg9CNpqc

[@Ratchet4647]

Yellowstone is a very interesting case for this. As mentioned in this video, vegetation can affect river flow. Wolves were once a keystone species in Yellowstone until they were wiped out by hunters and farmers. There was a conservation effort made where they brought in wolves from Canada. They found that returning the wolves changed yellowston for the better, including affecting the flow of its rivers!!!

[@candaceloftus1047]

You can also do this with satellite photos as well if you're looking for something more accessible. My mom was laughing at me when I was looking at the satellite photo on the in-plane entertainment screen and identifying dams and historic channels.

[@brandonadams7837]

@@Ratchet4647the wolves weren't directly affecting the rivers, but rather the behavior of he bison. With no wolves the bison were lazy and grazing in areas without moving at all until they had consumed all the grass, leading to erosion and run off which negatively affected the river. With the wolves back it forced the bison to being on the move which allowed the grasses to stay healthy and prevent erosion.

[@cvkline]

When I was visiting Alaska, I learned about "braided rivers" which are formed because of the extreme flood/dry cycles of rivers fed by glacial melt. They really do look a lot like the example on the right towards the end with the pulsed flow of water.

[@erinmac4750]

Thank you for your comment. I was trying to remember where I had seen it before! 💜🌎🏞️🍀

[@peepeetrain8755]

Braided rivers are really cool. Most are from glacial or snowpack melt as it is formed by heavy summer melting and little melting during winter. I've seen a few around my area in Australia but only during drought when rainfall is much lower than usual.

[@MrEazyE357]

You never fail to tech me something I had no idea I wanted to know, Grady. I feel like that should be a skill you should be extra proud of. Keep doing you my man!

[@kosica4126]

Okay wow, i'm hella impressed. Not only are the visual representations really nice to look at, you're explanation for everything was really clear and interesting to listen to. While i may not dabble in engineering or geology, this was such a worth watch and i can't wait for the second part!

[@user-dg9pu4pe9d]

Growing up, we had a pretty slow moving creek at the bottom of out property. The Crick was curvy. One bend was eroding in the direction of a road. So the township widened and straightened out the problematic bend. They placed cement slabs along the edges to prevent erosion. Worked great until storms caused the creek to flood. It partially filled in the new channel, eroded the new bank that replaced its original bend, and tossed around the cement slabs. While the road is safe for years to come, a new bend was made. The township failed to consider that the serene little creek turns into a raging torrent after heavy rains.

[@jonasmiller1739]

`

[@erniepasveer8027]

I work in in the Seismic industry (oil and gas exploration). We create subsurface images and we see these images of "river meandering" all the time. Often hundreds or thousands of feet below the surface. Quite fascinating. The deeper you look, the further back in time you are. Also, deep in the earth, old and gas love these old channels to "migrate" to other pockets.

[@gabor6259]

So if you go deeper, it's like a time lapse of the river?

[@erniepasveer8027]

@@gabor6259 Yes it is.

[@gabor6259]

@@erniepasveer8027 If it's not too cumbersome, can you talk a liitle about how you create subsurface images? How does it work? What equipment is needed for it? Is it something that the average person can do?

[@michaelyoung7261]

You should team up with Grady or Dustin (from smarter every day) on a video to better explain this phenomenon. It sounds fascinating

[@lawrencetchen]

Your most visually stunning episode yet, Grady! Not only colorful but there's something so viscerally satisfying about seeing the shapes and evolution of how water flows 💙

[@herzogsbuick]

The way those channels behaved absolutely blew my mind. I had no idea, but it made so much sense after you explained it, especially how the slope shallows out as a river meanders! That one -- woooo that got me going. Thank you Grady and emriver!

[@christinacody8653]

This is one of my VERY favorite topics. At the museum I volunteered at there was a stream table filled with microplastic aggregate (typically used for scouring walls) with two water sources on each end simulating a stream just like Grady is using here. I spent hours in front of it talking about the different aspects of river change. Given the one Grady uses here is from Carbondale, I think it's probably made by the same company (the museum I volunteered and later worked at was the St. Louis Science Center.)

[@dickJohnsonpeter]

The Proportional symbol in that formula is where ot gets complicated. I'm not a geologist but we did have to solve that as part of a midterm test in a calculus class for different variables in a river that goes to a pond our professor made in his yard. He was partly using us to solve problems he had with it lol but it was interesting and as simple as that formula seems it gets quite complicated especially with how vague a proportional can get.

[@TheGarratc]

I work on stream restoration projects, basically we take streams that are out of equilibrium (typically due to human impacts) and try to put them back closer to an equilibrium state by changing their pattern and cross sectional area to closer match what it should be. Good video

[@shadowfang13]

I really like this "series" (couple videos) I've always been fascinated by rivers. So happy you're making videos on it. I'm not an engineer, or even know much about it. Its just super interesting. You are really good at showing, and explain concepts.

[@lucbrinkman9709]

I really appreciate the visualisation of correlations with the balance at the 8 minute mark. I think it's a helpful and original way to visualise complex behavior, which is a hard thing to do

[@andrerenault]

Excellent video! I'm doing a master's in fluvial hydraulics, and our project team has found a channel configuration that stubbornly refuses to meander. It doesn't help that our grain size is massive compared to the channel width, and we don't have sediment recirculation installed yet... oh well, finding things that don't work is part of research!

[@wirelesmike73]

I've been easily fascinated by the movement of water over surfaces since I was a child. And, this model you've created illustrates precisely why. The imagery of the flowing movement is pure eye candy, and I could watch those playbacks all day. The natural world around us is amazing, and beautiful in the most unexpected ways. A little contrast and food coloring only make it that much more dynamic. 🌊👍

[@gunning6407]

The way you use this scale analog to illustrate the equation is elegant & ingenious. This is a beautiful video, thanks.

[@lucas.faria.v]

It's wonderful to see the scale of erosion and river changing behavior in minutes like this, I am not an engineer, but beeing able to see this and learn is incomparable, amazing display!! Thank you!

[@Gakulon]

As a geology enthusiast and student, that table is absolutely beautiful. I will always love learning about how our wonderful world works

[@robertball3578]

I am a mechanical engineer (retired) but studied geology as a recreational gold miner living at the foot of the Sierras and the gold country, a band of faults and volcanic vents. Early streams ran N-S, modern streams run E-W, cutting across the old river beds and exposing the gold that deposited in prehistoric times. A lot of fun but not enough income to give up my day job.

[@mbryson2899]

You have a remarkable skill at making topics that seem (to me) to be boring on the surface and making them genuinely fascinating. Thank you for sharing!

[@KarissaBoBissa]

Your model is truly one of the prettiest things I've ever seen. I would LOVE it if you could upload an uninterrupted length or time-lapse of the whole thing, to use as a sort of screensaver or "fireplace" video. Maybe the sand wouldn't last that long but occasional resets would be rad to see in the time-lapse too. I love all your content but this river model is *chef's kiss*

[@du4lstrik3]

I remember taking geology in college, and the rivers segment was probably my favorite part of the course. It's amazing how we can see the history of a river's path, develop around oxbow lakes and make predictions as to how it will meander in the future. After we finished rivers and sedimentation, I hopped on Google Earth and started perusing all of the rivers I could find to reinforce my knowledge gained from the class. The Mississippi is a great example of meandering, but there are also a lot of rivers in Russia near Siberia that are untouched and show heavy history of river movement. Check it out sometime! It's quite fascinating.

[@jacquescousteau4592]

I am a Biology Student and am fascinated with rivers and their development. Some years ago I searched for animations and models that could accurately simulate the evolution of floodplains and river morphology, I found a couple of simple animations and videos from "Emriver, Inc." that built these kinds of model tables which absolutely fascinated me. Now I can’t wait to watch your video about it. I am going to watch it tomorrow and I am so excited 😆

[@jacquescousteau4592]

However, I have to say, I would have loved to hear you address planning methods that include natural river dynamics in the planning of infrastructure instead of framing it as a threat. After all, we will need more natural rivers and stable natural landscapes globally in order to be able to face many of the threats we are facing.

[@TheKnarlyKarly]

I’m on the west side of New Braunfels, and your video helped me understand why a dry creek near us changes paths almost every time we get substantial rain. It’s a real world mini-example of what you explained here. Thanks for the education!

[@danwolfe7665]

This was a great video! I’m an aeronautical engineer and I loved the way you presented this material.

[@alexmcd378]

My family was very impacted by a moving river around 175 years ago. The deed to the hill where the matriarch was buried specified the river as the property line. The river changes course to the other side of the hill, and the resulting property battle turned into a Hatfield and Mccoy style fued. Thankfully that had settled down by the time I was born. 😅

[@amicaaranearum]

I’m a dirt lawyer; it’s always interesting to read old deeds that reference rivers and other features as property boundaries. Sometimes these outdated assumptions about the stability of natural features still crop up in the law.

[@QuantumHistorian]

That was genuinely beautiful. One of the few cases where video compression might have made something prettier, giving an almost ethereal appearance to the movement of the grains.

[@adamelliott2302]

Thank you!!!! The Mississippi is near and dear to me. I've lived along it in various places my entire life. In 2007 I had the opportunity to take a break for a while and kayak the entire river from head waters to the Gulf. Eventually I operated a canoe outfitter on those broad, brown waters. It was a real pleasure to hear you discuss the dynamics of a river. I did my best to read up and impart alot of what you spoke about to all. The Fisk Maps are real works of art! I have the map sections for the State of MS framed and hung on my wall.

[@khaldaeras7038]

The top down time lapses comparing two different flow types is mesmerizing to watch. Love it

[@theoneandonlyandyman]

I went to Winona State University up in Minnesota for a BS in geology. As a school on an alluvial island in bluff country on the Mississippi, we were big on both sedimentology and hydrology, because of how much our local geology had been shaped by them. Our department had two of these stream tables, and they were always so fascinating to just watch run over long periods.

[@ag135i]

You are one of those youtubers who give right and accurate information in a simplified way.

[@danielhale1]

Watching that river simulation was so good -- beautiful and fascinating! I'd heard about how rivers snake around because of sediment deposit, but it's something else to see it in action!

[@smokncho77]

@Practical Engineering This channel is amazing. I love your experimental approach to demonstrate large scale occurrences. I try to show people your channel, because I think these videos are good enough to be considered in curriculum. Thank you for the work you do!

[@andrewjmarx]

Have you done any videos on soil composition (clay, silt, sand, organic matter) or soil horizons? It's such a cool topic. I had an undergrad course on soils that had a field component where we went out to pits and "played" in the dirt and learned about it in the context of the surrounding geology. Super relevant to a lot of fields like engineering, but even as an ecologist, I've used soil data for modeling and predicting species distributions both in a contemporary context and a historical context.

[@andrewjmarx]

And more directly related to this video, I've also used slope, water flow, and water accumulation metrics in wildlife species distribution models because they can play a major role in the types of plant communities that develop in an area, which can then determine what animal species might be there.

[@DanielinLaTuna]

Thanks for the video, Grady. Can you also do one about California’s “killer Kern”, a fast moving river that drops 13,300 feet from its origins in the western slopes of the Sierra Nevada Mountains in just over 165 miles? It’s a serious elevation change that moves not only silt, sand, and gold nuggets, but boulders as well.

[@WayneWerner]

Small boulders the size of large boulders?

[@DanielinLaTuna]

@@WayneWerner , 👍🏼 yup; sounds like you’ve been on those stretches. On inflatables?

[@erinmac4750]

If I'm not mistaken, it's living up to its name right now with all these atmospheric rivers we've been getting. I'm wondering where all the gold is going to show up. 🤔 Edit: "up" 😸

[@DanielinLaTuna]

@@erinmac4750 , yes, it’s moving tons of water, with more to follow. This spring and summer will be a bonanza year for gold hounds. When I passed through Oroville, on the Feather river in Northern California several years ago I talked with one of the old timers there and he said they still get nuggets and gold dust in the riverbed sand, especially after a good runoff year. (Oro-ville means gold village in a mix of old Spanish and English...) I’ve seen gold in the western Sierras (Sequoia) before

[@Frostgnaw]

Thank you for all you do for us, Grady. I feel like I'm in my highschool physics class again. It's been a decade since I graduated and I feel like I'm back in school. Absolutely love these.

[@WinstonSmith0824]

I'm sure you know, but just to be safe, this is a lie and a scam. (The telegram message above)

[@ddaniels]

This video is so well done. My attention hung to every word and the visuals were really well done. One of your best, Brady! Well done! 👍❤️

[@christhemarketingguy]

Great video. I can't imagine how many people you have inspired with all your videos. They are always simple and easy to understand with all the examples, diagrams, and visuals. Thank you so much.

[@LillianCrawfishDE]

I graduated with a BS in geology, way back in the 80s. The biggest takeaway for me was that the earth is dynamic. The only thing you can count on is change. My appreciation for fluvial geomorpgology is second only to plate tectonics. Thank you for covering this topic. Longshore drift (LSD in the 80s) would be a great topic to follow this one. I'm always amazed that people want to live on a barrier island, which, by its very nature, is constantly moving and reshaping.

[@amicaaranearum]

We have a number of developed barrier islands in the area. It always seemed strange to me that people could continually get funding to fight coastal erosion and replace structures inevitably lost to the ocean. At some point, you’d think people would realize that it makes more sense not to build on land that is so dynamic.

[@paulthomson2288]

magnitude and frequency in geological processes is a topic most local government authorities responsible for environmental management have also obviously not fully understood especially recently in NZ after cyclone gabriel burst many river stop banks...

[@hoo7797]

The pulse flow erosion looks so beautiful, like draping cloth. Amazing how such destructive forces as erosion can create amazing, mesmerizing features in the process.

[@SharpAssKnittingNeedles]

I was the geology lab assistant for a couple years in school and we had an Emriver stream table. Fun labs, but I had the dubious honor of setting it up and preparing it for storage 😅 fun memories, and awesome video!

[@andreijecu765]

A behind the scenes or extended cut that can show how they separate the different particles used and the inner workings of Emriver and some large designs or digital models would be fun.

[@elizabethcook1577]

@emriver has a KZbin!

[@kindlin]

I would be all over that.

[@tombombadil811]

Your channel literally makes me so excited to begin a career in engineering, thank you Grady

[@mikelong9638]

Grady, as an "armchair geologist" I've watched countless videos on what causes rivers to meander. As you said in the beginning of the segment, it isn't an intuitive process. One would think that water would take the shortest straight line course to the sea. This is hands down the best explanation I've seen, and your models are outstanding. Thanks

[@michaelschmitt2427]

Fascinating. Your videos are getting better and better, I really look forward to each new episode. The question of why and how far rivers meander has long seemed mysterious to me, but thanks to your video, less so. Keep up the good work!!

[@Germankipp]

Loved this video, I once went into an internet hole about the Morganza Spillway and how the Mississippi River bed is several feet higher than its path of desire along the Atchafalaya River. It always concerns me with the amount of sediment human engineering seems to hold back from the coastal marshes, but I digress. Thanks for the video

[@notSwiftie]

Perfect timing! Just as I was gaining huge interest and learning this in school.

[@morgantouvereyquilling3465]

As a child I was fascinated by how a river in our favorite vacation destination would change each year. I loved building little dams or create new pathways and observe the river's reaction (one day I flooded a good part of a dry and a little to much flat but slightly sloped area my family was using for picnic, we had to take our stuff in an rush and leave lol). That river (and most other I enjoyed messing around with) was of the "pulse" type I realize. A very variable sub-bed at a year's scale, in a larger one with high solid cliffs, carved by the river for eons. That stream table looks like such a cool and fascinating toy. Could spend hours watching and messing with it!

[@kevinbyrne4538]

I'd never heard of "Lane's balance" until today. And the explanation of meander as a river's way of lengthening its course (to compensate for a steep change of elevation) was very insightful. Thank you for posting this video.

[@wrex509]

There's 2 parts?!?! Thats so exciting! This kind of stuff is so mesmerizing in time-lapse

[@d00mf00d]

Such an amazing topic! I love geology and geomorphology! Thank you for covering this in such detail:)

[@Arcexey]

Just got back from my first trip to New Orleans, which was mostly a flood tour by locals. Literally perfect video to see coming back. Thank you sir.

[@piropitiflautico]

This video is truly amazing. Your work of explaining complicated concepts to us simple humans is very much appreciated and admirable

[@Soggstermainia]

This is one of my favourite sciences. Been hoping you would get to use a full size water table to show us real examples like this for ages. It's your visual demonstrations that really help put across information.

[@WinstonSmith0824]

I'm sure you know, but just to be safe, this is a lie and a scam. (The telegram message above)

[@Soggstermainia]

@ErstwhileCanard I am aware the telegram messages that are scams are on tons of channels. Also it has now been removed.

[@rogervaught3985]

My geomorphology course had no texts so we had to read multiple books and reports on every topic. This video would have been so helpful! Very well made. This is how youtube videos should be made. Thanks!

[@beenschmokin]

Study Victor Schauberger. It will change your life

[@kendallwiggins6468]

Field Trip! This was so exciting. I first learned about river dynamics when preparing to spend a month in the Peruvian Amazon for an ecology/conservation study abroad. In that case, we learned about the importance of river meandering in the context of forest succession and ecosystem diversity. I love how this fundamental feature of our planet can impact so many different fields.

[@davidmills5286]

its 11:15 pm on a Sunday, and i just geeked out watching a youtube video about river erosion. Loved every second. Super satisfying time lapses and great explanations. thank you

[@muhxnnxd]

Love this video, hopefully we get more general geology related videos

[@mattlarson9897]

My high school geology teacher set up a table like that and let it run for weeks to show us how rivers meander. It is really neat to see how much it can change over time with no human input.

[@beenschmokin]

Victor Schauberger. Study his work. Plenty of docs. Rivers do not do what people think and he proves it over and over.

[@marcelomontero7446]

Thanks for this beautiful and educational video Grady. Rivers are just amazing.

[@Abel19129]

this one is definitely one of the best model i've in your channel. Love it so much!!

[@Leanzazzy]

This channel never ceases to amaze me. I love how you can make even the most weird and unassuming topics (at first glance) so much more interesting when you explain the practicality behind it.

[@gizzmo7301]

That graveyard looks like Hollywood cemetery in Richmond. 10:31

[@markdmeadows]

It is. That's right by Monroe's tomb.

[@tackontitan]

The online compression joke around 3:00 is criminally underrated and needs to be recognized for how good it is

[@erikaj1078]

Thank you for sharing, Grady! This is an interesting video from what I consider one of the best channels on KZbin. I love learning about the different things in the world around us. The practicality of your videos and your simple explanations help me to understand which in turn foster more interest and fascination.

[@rodchallis8031]

One of the things that puzzled me about our local river-- the Thames river in South Western Ontario-- is just where all the dirt ended up. The river currently empties into Lake St. Clair-- and there's no delta there. Looking at the depth and width of the ravines it carved that's a lot of sediment not to be accounted for anywhere. It seems most likely all that sediment was discharged via entirely different drainage. At the time the ravines were carved out, the river drained into other post glacial lakes, so the sediment is either high and dry on vanished glacial lake lands in Michigan, or as part of the Mississippi delta today, as those lakes at that time discharged down that river. I guess I'm so used to thinking of things in geology having a "geological time scale", meaning our landforms took eons to form, it's still surprises me how dynamic and radically different drainage in the Great Lakes Region were relatively not that long ago.

[@volentimeh]

There were some massive flood events connected to the last glaciation that greatly changed the landscape, quite a few comparatively tiny current rivers are meandering along the bottom of massive flood carved channels.

[@rodchallis8031]

@@volentimeh, Yeah, the "scab lands" out west are probably the most dramatic example of this, and there's evidence of this in the Snake River basin in Idaho. I'm sure there are many others.

[@kevinheard8364]

A sincere thank you to Emriver for their participation in this video effort. As you undoubtedly already know, Grady has received multiple commendations from even the 'experts'. "The whole world should see Grady's videos".... I, myself, ALWAYS learn so much.

[@davebujold5596]

Great video! Well Explained. Id love to see a ''part 2'' on water behaviour on hills/mountains, differences between a city hillside, a ski resort, hill side housing project, rock cliffs, farming valley, etc. Cheers!

[@coryrice1417]

Grew up on a river. I had a decent understanding of this, especially oxbows...but I understand a lot more now, thank you brother! Keep up the work!

[@defenestrated23]

Isn't slope usually change in elevation over horizontal length? The equation on screen at 11:52 shows S = length/ðelevation. That would imply a singularity for flat ground, which feels yucky mathematically, so I don't understand why they don't put the term on the other side of the equation?

[@toma5153]

Great demo. Would be good to explain why a really small model behaves in the same way as the real thing. For example if you have such a small flow rate you would think you needed a proportionally smaller sediment size.

[@marleybeem6537]

The stream table media is plastic and of lower density than natural sediment

[@k_slyons7346]

This is an incredibly intuitive explanation for something that I never needed to know but am so glad I do. Thoroughly enjoyed it!

[@karlinthesmarts]

Love the dig at video compression algorithms working overtime on those particle movements ;) Another excellent episode.

[@TrainsandRockets]

4:47 ... That's the map of my region...😍 I remembered just by the look of river because I had seen this river map hundreds of times...because I also wanted to see how the meandering changed in Ganga River... My childhood school came in path of changing river and it's half area was eroded completely... By the way I also took Civil Engineering 😊 What a coincidence that you chose this map...😁

[@redi6460]

*4:35

[@gijskramer1702]

In the netherlands this subject is thought from a very young age since rivers and the space they need is huge. You should take a look at the "room for the river" project.

[@WeyounSix]

There is a creek going through some property where I've camped every year growing up, and the creek has become more of a river over time, but not only that, I have watched it's position move and zigzag over time. It was really cool being able to see this first hand.