Practical Engineering - 2022-06-07
Some unexpected issues for engineers who design subsurface structures... Worksafe BC video: https://youtu.be/kluzvEPuAug Next time you see a dam, retaining wall, caisson, or any other subsurface construction, there’s a good chance that engineers have had to consider how groundwater will affect the stability. Even though you’d never know they’re there, some combination of drains and cutoffs were probably installed to keep the structure (and the people around it) safe and sound. Watch this video and the entire Practical Engineering catalog ad-free on Nebula: https://go.nebula.tv/practical-engineering Practical Engineering is a YouTube 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! CONNECT WITH ME ____________________________________ Website: http://practical.engineering Twitter: https://twitter.com/HillhouseGrady Instagram: https://www.instagram.com/practicalengineering Reddit: https://www.reddit.com/r/PracticalEngineering Facebook: https://www.facebook.com/PracticalEngineerGrady Patreon: http://patreon.com/PracticalEngineering SPONSORSHIP INQUIRIES ____________________________________ Please email my agent at practicalengineering@standard.tv DISCLAIMER ____________________________________ 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 ____________________________________ This video is sponsored by HelloFresh. Stock video and imagery provided by Getty Images, Shutterstock, Pond5, and Videoblocks. Music by Epidemic Sound: http://epidemicsound.com/creator Tonic and Energy by Elexive is licensed under a Creative Commons Attribution License Source: https://www.youtube.com/watch?v=U6fBPdu8w9U Producer/Writer/Host: Grady Hillhouse Editor/Production Assistant: Wesley Crump Script Editor: Ralph Crewe
I'm a geotechnical engineer (the field of engineering that designs dams) and I can say that, while extremely simplified, the presentation of engineering concepts in the video is very accurate.
if you can't simplify something complicated - you don't understand it well enough.
Hi, I need your help. We are going to construct a 10 story building which is designed to sit on a raft. But the raft is also gonna sit on a 3m thick layer of hardcore. But we have big problem with ground water as it overflows even the hardcore we have laid. What could be the permanent solution to curb this ground water? Thanks
Thank god he's great at simplifying things, otherwise he would have about 13 subscribers 🤣
Remember that the Lord Jesus Christ died on a cross for you because He loves you so much. He then rose up from the dead three days later
The Ten Commandments are called the moral law, (most of us are lying thieving blasphemous adulterer at heart and deserve hell) you and I broke the law, Jesus paid the fine. That’s what happened on that cross.
By believing that Jesus died on the cross and rose up from the dead 3 days later and not just confessing your sin, but also repenting of all sin you have done and putting all your trust in Him in prayer, He will grant you everlasting life as a free Gift
@Dove unsolicited religious comment, that doesn't have anything to do with the topic in discussion. So please refrain from doing this.
I'm an engineer and the concepts that you can efficiently describe in 10 minutes are worth hours of reading a text book. Love your videos!
Remember that the Lord Jesus Christ died on a cross for you because He loves you so much. He then rose up from the dead three days later
The Ten Commandments are called the moral law, (most of us are lying thieving blasphemous adulterer at heart and deserve hell) you and I broke the law, Jesus paid the fine. That’s what happened on that cross.
By believing that Jesus died on the cross and rose up from the dead 3 days later and not just confessing your sin, but also repenting of all sin you have done and putting all your trust in Him in prayer, He will grant you everlasting life as a free Gift
@Dove yeah ok... in what parallel universe does this have anything to do with the video?
I live in a town that apparently used to be a swamp or marshland on top of being in a geological bowl, so we flood almost every storm. it never occurred to me how difficult it would be for a civil engineer in this area. I love your channel cause it helps me notice these things
Grady, I just want you to know that I've been watching your channel for years but I was able to put one of your videos to practical use yesterday. My grandmother (who grew up one of 8 kids on a tobacco farm in Rockingham, NC) had seen both water towers and grain bins all her 88 years but never known what they do/are for, since on her farm they used a well and drying sheds. Out of nowhere she asked me that while we were driving. I was able to mostly explain it to her because of your video on water towers and Destin's video on "Smarter Every Day" about grain bins. When we got to the house, I showed her both videos. I wouldn't have been able to answer her without you guys so I'm thanking you both.
Great video, I'm a senior cad tech of 23 years and have done numerous dam inspection, monitoring and removal projects over the years. I usually get all the drilling and survey data and make detailed plans showing all the data. Your video was very well done sir! Just a month ago our survey crew went out to a dam that we had been monitoring for at least 15 years and was recently dewatered. I was shocked that the crest of the earthen dam sunk by a few inches after dewatering lol.
I've gotta say, Grady. I've noticed an uptick in the frequency of the videos you're posting lately. But no negative change in quality. I just want you to know that the effort you put in to make that happen is not in vain. I appreciate every iota of time and energy that you've put into this channel. It brings me and in excess of 2.68 million people a great deal of joy. It may not seem like much sometimes from your end. But one of your videos can be the difference between a crappy day getting me down, and forgetting why I even felt crappy in the first place. You really do change lives with this stuff. Not to mention how many you've inspired to pursue (civil) engineering.
@H You and me both. I grew up and went to school in the 90's. So I didn't really have the internet to benefit me much. Except the odd Lycos page I could find researching a school project. Not at all like the wealth of knowledge available to every lay person today.
The only thing that makes me think it WOULDN'T have been good for me, is just how distractible I am and how many distractions exist on the internet. Coupled with the lazy, unmotivated (more than now =P) person I was as a teenager. I know I wouldn't have been interested in watching anything like this back at that age. I probably woulda been the typical kid watching Pewdiepie or Jake Paul or whatever it is kids watch these days. Jeez that makes me feel old to say.
But my point is, I wasn't the right person back then to be able to take full (or any) advantage of the educational content on YouTube. I loved medicine, and watched surgeries on a TLC show called The Operation, before TLC became like LifeTime Network for Women 2. And there's a lot of surgery and anatomy videos on here I know I woulda loved. But that's about all I can think of. Man, reality sucks. But I guess that's why people take up drugs lol.
Well said!
A fancy way of saying thanks I appreciate you making the videos more frequently and I understand that it takes a lot of effort.
Pander harder NPC, he might see it someday! 😂
@H ?...what about ' asta la vista, baby ? '' '' ......no, i won't BE BAACK !
I build tailings dams and I absolutely love your videos. My friends and family have a better grasp of what I do because of them. Cheers.
Engineering is an amazing field that has so many possibilities! You're inspiring and I can't wait to see what you achieve next!
I was introduced to this concept during flood defense. Turns out it's too expensive to shore up a river with miles of concrete so you have to rely on good solid earth... And when the water level rises too far, any water seeping through is a threat that can only be contained by, not blocking the exit hole, but building a cylinder of sandbags around the exit that allows the water level to rise to the level of the river on the other side, equalizing pressure and stopping flow.
It's all so counterintuitive for laypeople!
Yawn 🥱 who asked?
@Woosh Bait I Asked.
@Woosh Bait I asked.
@Jacob Bachman yawn
A year or so ago I started working on the administrative side of a firm that does a lot of design and construction involving wells, lift stations, and so on, so these videos have suddenly become much more relevant to my daily life as I encounter the terminology on a regular basis! Thanks for building acrylic models in your basement.
As a geotechnical PM, I love your videos. My company will be drilling into a 100 foot earthen dam to address seepage issues. I look forward to seeing what solution we can come up with!
Love your models. Can you change the media in the model from uniform sand grains to different densities, like a layer of clay, a layer of gravel, and a layer of rock (maybe using spackle or some other mouldable material)? The groundwater would behave quite differently. It would be interesting to run the same experiments with different media and see what happens.
Hopefully your educational productions are seen far and wide. This featured explanation brings to light some of the hidden risks most people never see or even conceive during their daily lives because engineers have done the hard work - Thank you
I love that acrylic sand water flow demonstration! There are so many little experiment you could do with it. Groundwater is super interesting and I am always trying find ways to tie in fresh water with my classes--now I have another rad application! Thanks!
After a couple of years of watching your videos, I now walk around wondering how buildings, dams and bridges manage to stay up at all! In the early days of civil engineering, rather than some designs being unlucky, it feels more like the majority were just lucky!
Once one starts to watch disaster breakdown videos, this kind of perspective becomes even more intense! 😅
Even in best of circumstances there can be unanticipated factors leading to surprise results - but then add in cost-cutting, political shenanigans, and the occasional natural disaster or shonky contractor... 😬
I wonder how ancient succesful builders did the job...
Lots and lots of Trial and Error
I'm not an engineer of anything. But this video really explained the forces at work and how to resist them really well. Great vid.
🥑 Give HelloFresh a try and see if you like it as much as we do here: https://bit.ly/30Tr2CE!
📖 Did you know I wrote a book?! It comes out in November. You can preorder now for early access and other cool stuff: https://practical.engineering/book
🐦 I posted a little behind-the-scenes discussion about this video on Twitter: https://twitter.com/HillhouseGrady
Do you know any water engineers in jalisco, Mexico?
what if I use Practical99 instead, can I get more free meal? 🤔
jk thanks for informative video!
Hey I was wondering if there were any good resources to learn more about groundwater and storm water flow topics that you would recommend
I just wanted to say you are such a blessed man to have a beautiful family. Your children are going to be so excited growing up in a house full of engineering and science.
Really love your videos and the simplistic way you explain the science.
Hey, why use permanent marker on your demos? Get dry erase and you can draw all you like 🤷♂️
Years ago in school I did a CFD analysis of fluid passing through a porous membrane and it ended up just like your physical model! Real neat! I miss that type of feeling.
Thanks for the explanation! Groundwater is truly a thing, that not many people think about.
I've seen some funky things due to groundwater recently, so this visualization helped a lot in clearing out my misinterpretations
Your groundwater videos are seriously top notch. I never considered the implications of groundwater before and you make it so easy to understand. Along with your visual aides it's amazing governments/institutions aren't trying to buy these videos to teach their civil engineers!
Great video, narration, and presentation.
I have been involved with very deep excavations close to buildings that have almost inevitably had to be done by hand, ie: shovel and breaker, so I have a 1st hand appreciation of what you're describing.
Greetings from Melbourne, Australia.
Brilliant idea using the model to demonstrate each problem, so visually clear and making it way easier to understand!
It's insane that he managed to explain something in 14mins that took our tutor two 2hr lectures. I can't believe we're paying 9.25k a year for content that's taught far more effectively on Youtube.
You're paying for the paper to say "look I'm qualified" not the tuition nowadays
Companies should change the application process to just a test of the required abilities! Test passed? You're in!
Only real advantage i could see is that you managed to pass test and time management while at uni!
@Filippo Eich that is not feasible, unless they provide their own training. Theory helps and is a basic requirement but practical understanding will not come easy. You have to be naturally talented toward the subject to circumvent the lack of experience.
"You wouldn't pirate an education, would you?"
I studied chemistry at the local university many years ago. I also found, that I could teach another student in an afternoon, what took other students 2-3 weeks to pick up from lectures and reading a few chapters in a chemistry book. (specifically organic substitution reactions).
As I recall, the books used words that didn't really describe the effects of common side groups on the reactions too well. Essentially, the books were written in a way, that meant you had to read them really, really close, more than twice, spending hours on a few pages, trying to figure out what the author is trying to convey.
As a geotechnical engineer, thanks for explaining part of what we do! Actually, I would love to see an entire video describing the wide variety of scenarios, mathematical models, and methods we use to keep buildings straight and roads functional. No one knows what we do!!
@Anthony why spend an extra $5k up front when you can spend a ton of engineering time and concrete later
@zbou23 ....? you must be referring to leaning/sinking Millenium tower, in San Fran. What a fiasco.....686,000 pounds, of leaning cement.
@peter sack there isn't a plumb building in america ;)
One of the challenges of a great educator is to simplify concepts and tame complexity while keeping it scientific.
You excel at this and manage to make me understand and be fascinated and value all engineering work.
man, i really love your experiments. I’m new to the channel as I am trying to broaden my skillset from computer to general engineering. I want to replicate your experiments at home - I think it’s probably a great way to learn not only theory but practice.
Speaking of things unexpectedly sinking, I'd love to hear you talk about permafrost related engineering issues.
Hey Grady, I was having a bit of withdrawal from seeing the awesome clear plastic models that you build. Thanks for making me feel better and rectifying my withdrawal situation!
i have very very little formal education but you make these explanation videos so well that i always come out of them with a decent understanding of whatever the topic was when i previously had no understanding of it. a testament to the quality of your work. keep it up!
Can you sum it up for me?
I know, right. I also like Technology Connections content for the same reason. If you know of any other channels that explain things this well, please let me know. I hope you have a great week!
@Sagar Shrestha can you give me 100k USD? if not then no.
@Wabash15 honestly i dont know of anything thats as easily understood and universally applicable as this channel. but i will check out what you recommended
@saturation station would you like to take 100k USD written money 💰, 😈
Im a Hydrogeologist / Groundwater Engineer, thank you for such a cool visual display of familiar ideas, was a treat. You also explained the basics of the field perfectly, thanks mate.
Im an astronaut
I recently heard about the terrible trouble they are having at Fukushima with groundwater flows penetrating the basement and becoming radioactive. It seems they excavated substantially into the hillside when building the plant and this has left the structures unusually under threat from large groundwater flows. While Japan is short on flat land for construction, especially next to the sea which is needed for cooling water, this seems to me to be a reckless choice. Of all the things you don't want to get flooded the basement of a nuclear reactor is pretty high up on the list. It would be interesting to hear a professional point of view on whether this was a perfectly normal practice that has only become a problem because of the extreme earthquake and tsunami, or if they really shouldn't have built the reactor building into the hillside like this. The ground freezing techniques they are using to combat the problem are also interesting.
I've seen the proposals for a lot of water and wastewater projects.... There is A LOT of engineering copy and paste.
It's pretty scary actually and I can easily see how something bad can happen when the situation strays too far from the normal.
I love seeing your growing family! I hope everything is going well.
In the weeks before my daughter was born (3 years after my son), I couldn't imagine any possible way that my heart could get any bigger. I mean, as you're aware, the first kid ushers you across the Rubicon, a different ontological universe compared to The Pre Kid Times. But could it happen again!? Yes. It does. And a logical person such as yourself will appreciate how illogically this all happens. :)
My kids are 10 and 7 now, somehow, and I've long since given up on understanding how the journey works. Enjoy as necessary/possible, and clean up later. (Also, I'm not thinking about the imminent teenagers we'll have around here in a couple years. [fingers in ears... LALALALALA!!!!])
Best of luck in the coming weeks and months!
I love all of these models you create and actively demonstrate the topics being discussed. I wish there was more of this. Have you thought of expanding your team?
Hi Grady - Is it possible for you to do a video on the effects of over-pumping ground water for potable municipal water supplies? We live in Florida where the soil is sandy and population has been growing fast. Intuitively - I believe the result has been that the local water table around these “well-fields” gets lowered to a point where organic s in the soil are exposed to oxygen. The organics decompose leading to subsidence, often in residential areas where foundations are not built strong enough to resist pressures. Added to this were development practices where organic fill or “scrapings” were used to level certain areas to create more usable lots. With 5 feet of clean inorganic sand placed on top. I’m speaking from personal experience here documented with subsurface samples and ground penetrating radar studies. The part I am not familiar with has to do with the effect (for potentially miles around) of a lowering of the local water table. Not to mention saltwater intrusion when drilling near the ocean where most of Florida’s population lives. Mostly I’m interested in the more general hydrological engineering considerations as a result of “over pumping” the aquifer. Water is very expensive in Florida for these reasons. Most communities use reclaimed water to lower the pumping demand.
I can definitely add it to my list of ideas for future videos. Subsidence is a widespread consequence of groundwater withdrawals, and some places even have subsidence districts that regulate pumping (e.g. Houston). But the mechanism you described of organic decomp of topsoil isn't one I'm familiar with.
@Practical Engineering I remember from my intro hydrology course the picture of the telephone pole in California that subsided something like 20 ft
Subsidence is caused by the over-pumping of aquifers leading to the pore structures in the soil collapsing. I haven't heard of organic decomposition causing subsidence but if you could link some resources I'd be interested in reading about it. Usually, organic soil has oxygen available for decomposition unless it's a wetland or used to be a wetland and the organic material is deep enough for oxygen not to penetrate.
@Practical Engineering Subsidence due to lowering the water table is an interesting topic for sure. In the area around Gouda in the Netherlands (yes, the same name as the cheese) the groundwater level is extremely high. The soil consists of peat and has a very high organic content. If the water table is lowered, the ground will be exposed to air, and hence the organic matter will rot away almost completely. The desired effect of lowering the water table is completely overturned. The need to pump out water from canals becomes even more important.
If you want an over-the-top case study for Subsidence, check Mexico City. The whole city was originally built on top of a lake, and has (or used to have) a huge sinking rate.
Enjoyable and informative as always. Perhaps in a future video you could go over the remedial work that was done to repair the Old River Control Structure on the Mississippi River after it almost failed during the flood of 1973. I've seen it written that had the dam (more of a weir, really) failed, the course of the river might have been irrevocably altered.
This video really help demonstrate what was happening in one of my natural filtration systems I’ve used on koi ponds in the past. The deco gravel was being eroded in short period of time and now I see just how fast that water was moving through the gravel.
Thanks for all the great content Grady. I work in building construction, and because of my exposure to some of the engineering content you cover I can say you do a great job explaining these concepts in layman terms.
It was interesting to hear you talk about the sink hole in BC. That's where I live and remember this event right around the time we were digging a 90' deep hole for a tower in downtown Vancouver and the hazard alert from WorkSafeBC was circulating...
Hey Grady, have you done a video on the engineering on mountains or steep, rocky surfaces? I never know how they do it and how they build roads and structures on sheer cliffs sometimes. Or even when the ground is just rock and sand. Thanks
We just had to have our in ground pool removed (broken up / filled in) due to ground water issues in our neighborhood. Each year, over the winter and early spring, the excessive groundwater would “float the liner”. Each time this happened and the liner settled, it would pull away from the track and return jets, either tearing it or creating a weak point. Several options were discussed to deal with this but all came with a bigger price tag than the pool was worth to us.
this definitely explains why, after resolving water management issues at my house, it only took a few months for water to find its way back in to the udrain and thereby to the sump.
@Chris DawsonI'm interested in his comment, as are a couple hundred people. It's relevant to the video.
@Chris Dawson what are you talking about? We're talking about engineering not politics. You're attempt to guess someone's nationality and political affiliations based on absolutely nothing further confirms your ignorance for all to see. I'm sure your next post will just be additional proof of foolishness and immaturity.
@Dan Don't reply to trolls, mate, that's what they want.
@Dan some trolls will say anything to get a response. There's nothing to understand.
@moonra true, thank you!
A very similar incident happened in Alaska in 2010. A crew was working on a water well for a prison construction project I was working on when one of them was swallowed by a sinkhole right next to the well casing. He, unfortunately, did not make it being buried under 15 feet of soil.
Thanks again for a great video! Your series about groundwater have really helped me understand subsurface dynamics.
These 2D acrylic models are fascinating and are a great aid in simplifying and visualizing the phenomenon. Maybe a collab with Steve Mould down the line would be interesting! Since you both are trying to explain complex problems using 2D models. :D :D
Great visual model. It’s great to have so many dam good engineers 😂 (I’m a geologist). You provide videos with quality technical content that are easy to understand. Great work! Also, Congrats on the new baby.
Living in a very Karst topography dominated river valley area, i have been able to locate underground streams thanks to knowledge i picked up via videos like this. My livestock would like to thank you for their (virtually)never ending fresh flowing water supply. The chickens have been loving the mud bugs (crawfish) living in along them as well.
I've never been more glad to live somewhere where there is only 6 inches of soil before you hit rock.
It always amazes me to see people digging really deep holes with nothing more than a shovel. If I do anything more than scraping the surface I have to break out the pickaxe or power tools.
haha, we say the same thing here in coastal BC. But there are river valleys, etc where the soil is deeper.
I remember trying to dig holes for various things growing up and always hitting massive boulders or at least 100+lb rocks within the first 12".
I live on an ancient lakebed, it's basically several hundred feet of gravel. So diggings frustrating unless you have big equipment. It handles water well though. In spring you can literally see the surrounding hills draining themselves of water after the ground thaws by the trail conditions. The driest areas will be on top first and then spread down.
we have places like that here too. no foundation needed for the houses just to level it. but digging a cellar underground its a nightmare. opposite to that where i live i bet the only rock i find is what we put in there. we have like 50cm of soil which is cultivated in some way, then brown clay for a meter and after that grey clay till the end of the world :D
We've got a huge gravel layer under the first meters of soil. No amount of rain has ever been able to flood the land here, except some underpass that will clear itself within a few hours at worst
...and here I am with our house sitting on the side of a sand hill. Our neighbours to the back have their ground floor at the same level as our 2nd floor, our gardens are separated by a 3.5 metre high and 130+ year old sandstone wall.
When our neighbour to the right excavated for a small kids' pool near the back of his garden, a section of that wall collapsed...
💦🇳🇱🏗 Living in the Netherlands, water management is crucial, especially when constructing below sea level. It's fascinating to see how the intricate control of groundwater plays a vital role in building and maintaining structures. The complex paths and techniques involved in managing water flow are truly mind-boggling. I'm curious to delve deeper into this topic! 🤔🌊🔬
Really great video 😃😃 ! The models are awesome, i would have such a harder time understanding if they were not here 😊😊.
Something i would add for the future if you ever do another video with this type of demonstration is when you're talking about areas of low and high pressure is mark which are which with just LP and HP. It would help out a lot people who, like me, are interested enough in the subject to watch videos about it but who have not received any formal education on it and need a moment to understand what is what on top of understanding what you're talking about.
Something i wished you had explained in more details are the equipotential lines. When they were straight i understood the concept but once they starting getting all bent and connecting at the top that understanding flew out the window 😅.
Maybe someone can explain why and how they do that 😅 🧐 ?
Just my two cents, keep ut the great work !
MrBlueBurd - 2022-06-07
Living in the Netherlands, water, and especially groundwater, is a massive part of life around here. It's good to finally learn how we control all that when building anything a meter below sea level.
Voltaic Fire - 2022-06-07
I imagine ground water is not just an important but a somewhat terrifying matter when a good part of your country is at permanent risk from the ocean, rain, adverse weather, and pretty much all water on top of it.
EnlightenedSavage - 2022-06-07
Same is true in the state of Florida. You take about one meter you will hit water. Plus we have sinkholes. It's similar to building on top of a large brick of Swiss cheese.
volvo09 - 2022-06-07
@EnlightenedSavage yeah one thing I noticed when I have visited Florida is just how many wells there are. I figured it must have been easy to hit water because just about every lawn sprinkler has a well.
MrBlueBurd - 2022-06-07
@Voltaic Fire Not really, to be honest. Flood insurance, for example, is just not a thing here. Our water management infrastructure is so omnipresent and so fundamentally integrated into every level of life that we just don't think about it anymore. There's even a level of government which is equal to but distinct from the province level called the watersheds. So 'It's taken care of' is the mindset most of us have.
Voltaic Fire - 2022-06-07
@MrBlueBurd I have seen your water management infrastructure, it really is impressive, but I'm a worrier so I do not think I could adopt the same mentality.