The 100 Year Flood Is Not What You Think It Is (Maybe)
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- Опубліковано 7 лип 2024
- Today on Practical Engineering we're talking about hydrology, and I took a little walk through my neighborhood to show you some infrastructure you may have never noticed before.
Almost everyone agrees that flooding is bad. Most years it’s the number one natural disaster in the US by dollars of damage. So being able to characterize flood risks is a crucial job of civil engineers. Engineering hydrology has equal parts statistics and understanding how society treats risks. Water is incredibly important to us, and it shapes almost every facet of our lives, but it’s almost never in the right place at the right time. Sometimes there’s not enough, like in a drought or just an arid region, but we also need to be prepared for the times when there’s too much water, a flood. Rainfall and streamflow have tremendous variability and it’s the engineer’s job to characterize that so that we can make rational and intelligent decisions about how we develop the world around us. Thanks for watching!
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USGS Stream Gages: maps.waterdata.usgs.gov/mapper...
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As a water resource engineer, I frequently have to explain the idea of the 100-year storm to people. I may just start showing this video instead! Nicely done.
Few days ago in german was (for our conditions) a 100 year flood. About 160 ppl died in it.. was the second 100 year flood within 10 years tho, many people say stuff like "so, that was now 100 years already?" right now.. thats freaking annoying xD
@@terrorhuhn9192 so, tbh, wouldnt it therefore be a decades flood?
@@terrorhuhn9192 It's ALSO because the estimations are falsely based on bell curve probabilities. It's a total load of huey.
This is precisely the content that I WANT to watch on UA-cam, but am never quite able to track down.
im a student in civil engineering and this dude just showed you how much we go through in water resources/hydraulics class
@Alex Tyson sorry, didnt mean to sound arrogant in that comment. my intention was that it's cool yall got to see what we go through in class, that's all. I finished that class and I still dont know much!
@Alex Tyson The proper terminology is "nobody cares Moby". LOL
I think you did our job as civil engineer in educating the society and inspiring young people. Never stop posting!
As a Dutchman, this hits pretty hard today, with all the flooding.
No worries mate - after it's done, you're good for 100 years!
I also got this recommended. I live in Germany....
@@MrJeffcoley1 1250 years for rivers. The Dutch learned long ago that 100 years is not enough.
That feel when 7 out of 9 of your friends in your standard deviation excel spreadsheet are made up
Yeah, Duke Flitznippler is totally real...
@@PracticalEngineeringChannel Charles. No last name, just Charles.
Not convinced Made-Up Friend 5 and Made-Up Friend 6 are different people. Maybe they are clones.
Pfft friends
The technical term for friends is standard deviations.
Duke F L I T Z N I P P L E R
Another thing that really needs stressed is that "any given year" starts tomorrow. And another point, the flood plain is part of the river, just not always.
Needs “ to be” stressed.🙄
But yes, the flood plain IS part of the river.
I love that your sarcastic comment about someone's typo is edited for corrections.
lol well done, you're a true credit to the species.
"Good enough." - The entire methodology of my hydrogeology class.
I found these absolutely fascinating. The fact that you're a fellow Texan made me a subscriber.
I work for the USGS, was nice to see the recognition, thanks.
Not being mean, I've always heard the public sector is where you go when you can't cut it in the private. How true is that?
Absolutely not true. Some of the sharpest engineers I've ever worked with were from public agencies like USGS, USBR, and USACE.
The public sector gets more scrutiny than anything in the private sector, because so many in the private sector rely on the information they provide. You're probably mistaking your experience at the DMV, which is a state thing, not a federal one.
Public or private, it all boils down to the individual's motivation to do the right thing
I'm a Water Resources Engineer pursuing my master's. Most of my work is depend on the data collected from USGS. So thanks 👍
That was good. You didn't insult anyone's intelligence or tried to joke through the hard stuff.
Yup, left that to the comment section lol.
True, except for the part about taking selfies in front of your rain gauge, lol.
@@bobsagget823 Dude, what the hell?
@@w.o.jackson8432 If you look at the discussion tab on his channel, you'll see people have been leaving mean comments for _six years._ Either he's still quite young (and he started his channel when he was, like, ten) or he's been an asshole for a long, long time.
bobsagget823 .
Grady: "we can't make everyone buy flood insurance"
South Amboy NJ: hold my Bud Lite
Another clear and understandable explanation Grady.
I love your videos.
I've worked in the engineering industry for almost 40 years and it still amazes me how the general public view statistical base data.
To most it seems that 1 in 100 year floods means that the chance of a flood happening in these zones is once every 100 years. Statistics are obviously not well understood.
Keep making these clear and simple videos. Maybe the public will start to understand their environment better. 🤞
We need more UA-cam channels like this!
Starfish Prime look at Real Engineering, Wendover Productions, 1blue3brown, and The Engineer Guy
UA-cam would still ban and remove them as its systems would see as it is reading material from a book becomes a copyright violation. Even humming a song UA-cam would remove it.
Very interesting video. As a CAD technician (Stantec Consulting,) focusing on water and wastewater facilities, I have often included flood plane data in drawings and (wrongly) assumed that it was "the worst flooding that has occurred in this area in the last 100 years". This was a excellent balance between presenting a "simplified" explanation without wandering into a "overly simplistic" one. This was a GREAT introduction to hydraulic engineering that has sparked my interest to looking into it a little further. Thanks much, and post more!
Going down the rabbit hole...... FEMA floodplain boundaries are more "easement" than engineering. If someone asks you to draw it and label the elevations make sure your surveyor checks the vertical datum on your plans first.
This is so interesting. I grew up in Central Texas. In 1998, we had a 100 year flood, then in 2002, a 400 year flood. It was very confusing for me as a kid.
This same sort of misunderstanding of statistics happens in finance as well. For example many (most all I think) use a measure called "value at risk" to quantify the uncertainty in their portfolio. So for example after doing a bunch of highly dubious statistical work they may say that their value at risk is $5 million dollars with a 95% confidence interval and a 1-day holding period. So depending on how the confidence interval is defined, that can mean either 5% or 2.5% of the days will have a bigger loss than $5 million dollars. However nobody thinks about all the $4, $3, $2, and $1 million dollar losses that will encompass 50% of the days and can all get strung together if the market is against you. The 1 day holding period is key, if you cannot exit your position in 1 day the total losses from a market event can be well above the stated value at risk. A good rule of thumb is that if you can't get out of a position the total losses possible in a year are about 11 times higher than the stated value at risk, depending on the volatility and liquidity. And then because many financial and commodity markets are log-normal, the stuff inside the 5 or 2.5% can be dramatically larger than the stated value at risk. As the probability of occurrence is going down the impact is going up exponentially. This is how you get a bank failure or market crash. They don't happen very often, but when they do there is not much that can be done. Some very large trading shops have been taken down by events they thought couldn't happen based on statistics.
In this case the 100 year flood actually was what I thought it was.
Harvey is gone Irma is coming, every month a 100-1000 year risk.
Willie van het Kerkhof
To hell with Harvey. May we never see another Harvey like hurricane again.
same here
I don't understand why people would expect it to be anything different. When I first heard the term "100 years flood" I thought "The size of flood that would occur on average once per 100 years?". Admittedly I termed it that way in my head, not "the flood size with a 1% chance of occurring each year", though that is a fairly simple mathematical relation, and if asked for the chance per year I would have replied with 1%
Yeah, same. Though I guess as a Dutch person I already have a larger than average reason to know this stuff.
Just found the channel through Hydraulic Press Channel and I'm loving it, immediately subscribed!
Really well put together videos with fantastic pacing and a pleasing balance between the accessibility and depth of the content.
floods are dangerous and can attack at any time. We must deal with it
vat da fak!
The National Weather Service in the US also allows you to access the Hydrology Data because they also care about water flows in streams so they can issue flood watches and warnings. If you have a stream that floods often in your area, you are likely to have a flow gague on it someplace. Also Highway departments put data into the system, because many bridges essentially have a ruler built onto a pylon that is visible from shore. Some times those also mark record high water events.
Thanks for the video Grady.
We all appreciate the effort you put into them 👍
Keep Making Cool Stuff!
Studying Mech. Eng. in school right now, I really enjoy seeing these videos. It's a good reminder that engineering is more than just studying.
loving the new channel direction - keep it up!
+Nick Ferry Thanks Nick! I want to feel your beard.
Practical Engineering lol - I wish that was the first time I have had that request
+AvE taken?! It's always been there
***** maybe too many pixeys
+Nick Ferry This chain of comments makes me happier than it should.
Also, what's with people wanting to feel beards? I've been stroked a number of times, occasionally without consent.
As a former civil engineer working with hydrology for bridge design, this is a fantastic video. Great explanation of the topic and the pieces that make this up. Keep up the great work. Your videos are informative and very entertaining!
Great vid!
Liked the selfie shot with the rain gauge (I do that too) and the last shot of skipping a stone - always good to feel like I'm back out on the river.
Keep up the good work!
Great video. As a fellow civil engineer, I have to explain this all the time. The other confusing issue for lay people is the 1% flood vs the 1% storm and why they dont occur during corresponsing rain events... Keep up the great work.
Don't know how many times that I've tried to explain 100 year storms to people, I never do as well as you. Maybe someday explain retention basins and metered outfall. Don't know if that's in the code in Texas, but here in Ohio they've been a big part of the building code for about the last 20 years.
been doing basins here in NJ since the 50's or so. we'e elevated it to a level of requiring some kind of Mage to figure out how to make them do all the regulatory requirements - water quality, erosion control, infiltration, flood control. Yikes!
Hi, I'm a civil engineer specializing in water resources, I've never heard of "metered outfall," what does that mean?
i am so stupidd that i dont really understand most of what he said . certain things just make sense while the other stuff is just extra words added to make it sound professional .
You've improved your editing a lot. And I like your humor. Even if it's weird, it's genuine. It is part of the world of top level engineers that you're exposing.
Thank you so much for making this video! I have heard people talk about the 100 year flood, and completely misunderstood it. Your explanation was very clear and interesting!
Mies van der Rohe built the Farmsworth House to sit right on the edge of the 100 year flood plain. Then for good measure, he raised the entire house 5 feet of the ground. Since it's completion,, it has been hit by two 500 year floods causing massive damage to the house.
farnsworthproject.org
Hey Grady, I just found your channel last night and Im getting obsessed with watching your videos. I just started my 3rd semester as an engineering student here in Virginia. I've only been here for about 2 years, but I was born and raised it Manchaca so it was cool to find out that you're a fellow Austinite. Thank you very much for your videos!
This is what makes the internet, shared learning and collaboration and cooperation awesome!
Thank you for adding to the body of knowledge ! This is a great point you should expand on ideas such as black swan or six sigma events!
A great example of dynamic teaching using web technology will replace standard engineering courses. Comprehension is everything : )
I KNEW IT! In one of your other videos I saw a highway underpass that looked very familiar... From Austin, you are!
Hey, thank you for explaining this. I do work as a junior architect and consistently find myself throwing basic property information like this on my general sheets. I didn't fully understand the difference between the flood plains (you would think we'd touch on it at uni at some point). Either way, I respect the work our Civil and Geotech consultants do--this was a great example of how their expertise is necessary--and allows me to do my work.
Dude, your presentation is sweet to listen to. You have a fab (and calming) voice ;)
This presentation is well done.
It would be very helpful for engineers to understand the changes to hydraulic head by flows into and through storm water pits. I think that a lot of unexpected flooding occurs because we have built storm water pits that aggravate hydraulic head. If you do a report on this topic them please tell me. I am easy to find. Thanks.
I have been there and done that. After living thru a 100 year flood, seeing my entire city go under water. I know exactly what it is. Further I know what it is to deal with the aftermath, the cleanup, the destruction to families heirlooms. The pain and the healing.By far the clean up and getting back to life is the hardest part of a 100 year flood.
Awesome video and especially applicable with Houston, hurricane Irma, etc. You do a really good job of presenting concise explanations striking a good balance between the technical side and using layman' terms.
Rofl that 2 second clip of you taking a selfie was a brilliant treasure of comedy that I hope everyone payed attention to.
I think you forgot the link to the FEMA flood plain maps. Great video, though. Very interesting!
+TheBookDoctor Fixed! Good catch.
The 100 year flood reminds me of a principle we use in electronics engineering called "mean time between failures". I've seen it mostly used to describe for measuring the failure rate for latching an asynchronous digital signal, where failure is when the latch goes metastable (i.e. oscillates between 0 and 1 by itself).
The units are in time, but it really reflects a probability that it would fail, e.g. we want the mean time to be in days or years, but all that really means is we wan the probability of failure to be in the parts per billion/trillion.
MTBF is also common on hard disks.
And it can be quite misleading, because it turns out HD typically fail young or live old, so combining those lifespan does not make that much sense.
When politicians and concerned voters see the bill of the flood protection projects needed, or how many people/businesses/industries/facilities must be evicted out of the floodway, and how much land would be needed elsewhere to relocate all the affected activities, they'll shriek in pain and agony and sweep the problem under the rug.
That is, until the problem starts costing dozens to hundreds of billions of dollars per year, every year. As it's happening with climate change inducing more extreme weather and sea level rise giving more inland reach to coastal storms.
For instance, the US Army Corps of Engineers is evaluating the feasibility of constructing flood defenses for Galveston bay and the Houston Shipping Chanel. Price tag? $90 billion. Cost of Hurricane Harvey (2017)? $125 billion. When did the next nasty storm happen? Tropical storm Imelda, 2 years later.
I first encountered MTBF in the military, where weapons and vehicles, as well as other major equipment, was listed with MTBF (or MRBF - Mean Rounds Before Failure) to give the unit quartermaster working estimates of how much to order, and when.
Thank you for a good link to share with friends. Your videos are an interesting and efficient use of time, though I'm glad I can replay parts of it a few times when it's deep, so to speak. Approachable engineering and science material is a wonderful thing to share.
Grady, I just discovered you a couple of years ago and now going back to watch your old videos. Your production value has increased a lot (not saying this to downplay your older videos but you're definitely getting better at your craft!).
Missed a chance for a pun at 7:04: "[water] shapes every facet of our lives" and faucet of our lives!
5:00 hey pervert why are you recording me?
I was recording the stream gages I swear!
tell that to the police
haha she looked over too
I adore this channel
You are one of the reasons I have decided to go back to school and finish my engineering degree
Thank you, Sir 🙏
Hi! Really appreciate this video. Thanks for makin it!
The number of dislikes on your video really doesn't matter, and as long as your video isn't factually incorrect, uninteresting to the point of tedium, or a controversial opinion, you're unlikely to have more than a few percent dislikes. Inviting the audience to honestly represent their feelings about a video using the like/dislike buttons or by leaving a comment is more endearing than directing them to hit "like" regardless, and won't negatively affect the outcome.
Can the past floods in Germany, Belgium, Austria be in this line? Nobody expected this.
Obviously. The problem with floodings is: the higher the flood level is, the less likely it is to occur. if you look at a 1000 year period, then you'd see that certain flood levels are reached 10 times in that period - that is the 100year flood level. From a single event, you can't tell that easily though. There are problems with this statistical analysis though because various boundary conditions have changed over time (climate, think of the small ice age in central europe), building density (especially in such highly populated areas like the rhine-valley), river straightenings... And what you have to remember: a 100 year flood occurs around once in a life time. There is a high chance that there is nobody alive to tell you about it. For comparison the flood level markings at Schloss Pillnitz: upload.wikimedia.org/wikipedia/commons/6/6a/Hochwasserstand_Pillnitz_Schloss.jpg You can clearly see that the last flood before 2002 was 150 years ago. There simply was nobody alive anymore to speak about it. I think the same happened for the floods in rhine region this year.
It's only for Americans, they don't think there is anyone else other then them
Thank you, your explanation gave me a much better understanding of flood plains and the 100 year flood. This will help me determine where I relocate. Your videos are the best!
5:00 I really appreciate the beauty of this stream guage.
that just made my brain hurt... but good stuff.
Chase Mixon he feeds information too quickly and often does not explain much about a concept and rushes to the next one.
new2k16rapper Pretty much how lectures work in higher education.
The information he presented was very bare-bone. Explaining every single concept in this video would take hours assuming the viewers have the basic knowledge of fluid mechanics.
And no this is not how lectures woke in higher ed, it's meant for an audience with little to no knowledge regarding the subject. He barely went over any math except for some basic statistics and rudimentary formulas.
Basically all you need to know is that take the phrase "x year flood". Take that x and put it in the fraction 1/x and then convert that fraxtion to a percentage. So a 100 year flood would be 1/100 which equals 1%. The larger the x the least likely it will flood in that area
@5:02 I ride my bike by that gauge every day on my way to work!
Yo! Travis County whats up! I grew up there, but now I'm in Atlantis (Houston). It's so cool to see local (somewhat) people creating amazing videos like this that are viewed by thousands of people across the world. Btw totally agree with changing the x-amount year flood system to an x-percent chance system, I was a little confused on why they used that terminology in my civil engineering classes last year. Can't wait to see the next video!
Thank you this was informative and you broke it down just right. I am trying to learn one new thing a week or so. Keep up the good work.
I've watched your channel for a while now, and I'm loving all the information (for an engineer to be)! What type of Basin Modelling software did you use? Secondly, how did you model the Flood Map Service? Thanks!
Thanks. For this video, I didn't perform any modeling. I was just showing some examples. There's a link to the FEMA map service in the description.
What program did you use to show those examples? Thanks again!
HEC-SSP and HEC-HMS
And with recent happenings in Texas, this video has made it's way in to the Recommended Videos again.
Now I need to get a rainfall gauge so I can check it obsessively and brag to my friends.
Excellent video.
I have always been curious about all the stuff we see everyday, your book is the best thing I found this year. Keep up the good work .
Fish jumps in foreground → 0:43
Good eye! Fisherman? Lol.
thank uou
Mmm, that is actually exactly what I thought the 100 year flood was. The only people confused were the people who think that they can be "due" when gambling or something.
More people would probably think they were "due" for it if they called it a 26-roll dice throw. It's a terminology issue.
26 roll?
They should call it "the 100-sided die roll". In this case, a critical fail being a flood. ...And a critical success being that you become a hydromancer.
It seems a lot less crazy to believe there might be cyclical behaviors in nature than in the behavior of dice. This is especially true since we *know* the days, months, years, and seasons are cyclical as are less well known phenomena like earth's axis precession, the sun's 11-year cycle, a possible 105-year cycle seen in carbon-14 studies, and more. It's not just astrologists or gambling junkies who might think a "100-year flood" probably refers to something cyclical, even if it doesn't.
Yeah dumbasses be dumb as usual.
I work in the Engineering Department in Bridgeport Connecticut City Hall. I get people in my office all the time complaining about being in a flood zone and saying "I've lived there 30 years and I've never been flooded!" Now I'll just show them this video to save myself some time of explaining. Thanks!
Thanks for the nice video. I just studied NRCS TR-55 at my hydrogy class and this video really helped me understand a lot!
The fact that this video appeared on my feed right after Hurricane Harvey.
Well you got my sub easy information to digest on a curiosity click :3
I couldn't have agreed more. Guy seems to have his shit in one basket, I enjoyed it really.
this is my third vid, glad i found this.
:3
Thank you so much for the video. I have experienced catastrophic flooding many times in my life. This video gives a great perspective of how many variables come into play in circumstances that cause flooding. Thank you.
these videos have so much content and you actually learn something. and can take notes if you want to actually remember
Woo woo, Hydrology major represent.
AdamOrnelles usually you need a masters for hydrology
It's nice that it comes today in my recommendation. Is it because of the events in Germany?
I also got it (again) in the recommendations. Grüße aus Hamburg
probably that's the reason..
algorithms hits u xD
The algorithm works in both mysterious and predictable ways.
Yo, not even done with the video and I subbed. Great stuff. Really gets me psyched to become an engineer.
This is one of if not the first video that decently explains storm water concepts! Thank you so much! You should make a video on what a Storm water pollution prevention plan (SWPPP) is! ;) (Thats what I needed to learn, usually I look to UA-cam to learn about stuff I have no idea on, but there was almost nothing on the subject which was kinda disappointing because it is something that is important to consider. Ive been subed for awhile so this was a pleasant surprise! Thanks for all of your hard work.
5:04 nice.
Yeah; gotta love that stream gauge. 😉
7:39
Bruh.
haha I was gonna say that too #buns
I knew that comment would be here
ha, Civils, with your using imperial units, and you're huge estimations, and your concrete canoes.
Geoffrey Vonbargen and providing clean safe potable water to your house that conveniently comes out of a tap that you can turn on and off at will. Then to 'tap' it off (sorry couldn't resist) we'll also provide you with a convenient way to remove your wastewater and treat it for you.
Thank you Civ Eng.
Imperical units is not something typical to this field of research. More like geographical *uche* the USA *uche*
Something wonderful about watching videos that deal with things I deal with and have to design around at work.
Ah rational method, hydroflow. So much storm water design in some areas for well pad design.
I really appreciate that you share quality engineering videos for young aspirants to learn and design future communities.
What's the probability of a 100 year storm occurring in a 100 years if it's normally distributed? The answer is not obvious.
The probability of having exactly one 100 year storm in 100 years is 37%. The probability of having at least one 100 year storm in 100 years is 63%. This is application of binomial statistics if you want to learn more.
That is correct, thank you! I love your channel and have watched all the videos today and study civil engineering myself.
IIRC an event with probability 1/p happening exactly once in P trials is always ~63% which I think is a pretty fun fact.
+Kevin Markielowski Isn't this the geometric distribution?
Angel33Demon666 man its been a while since college! A geometric distribution is basically, "how many until" whereas a binomial is "how many in x" they are very closely related. In my example above its probably of 1 "successes" in p years, so you can use binomial, I think you can also use geometric because some factors will cancel out.
>engineering
>users imperial measurements
This was really interesting. I am an architecture student and currently my class is working on projects in an area with several rivers. We were told to consider the 100 year flood plain and have all the data for it, but it was never explained to us how it worked. I kind of assumed more or less correctly, but this video really cleared up the uncertainty I had.
Very interesting video! I live in a flood plain area and did my own work determining our risk on a new home. I had the advantage of having the TVA as a great resource. Thanks for this excellent video!
Physicist here: Measuring something to 1% is no walk in the park. This is even more true when you're talking about understanding the shape of a distribution out in the 1% tails. Even if you have a theoretical basis for the shape of the distribution, the 1% tails are generally mucked up by instrumentation effects, noise, background, etc., etc. So, if you think the technical parts of this seemed hard, I suspect it is even harder than it appears while, simultaneously, requiring a substantial amount of prayer and a fair bit preparing to run to high ground anyway. Nice video!
5:02 Nnnice
Fever Dream Stream fuckboy
Love all of your videos, Grady!
Meme a killer ass videos in the sense of they're informative and they're fun to watch keep it up man you put it all together really nice and really well
Oh, so the 100-year flood actually IS what I thought it was.
7:37 missing closed parenthesis
Thank you so much for saying that! I'm so glad you pointed that out!
i wish i had seen this video when we studied engineering hydrology last year . thanks a lot . u made my concept more clear.
As a hydrologist, that is a beautifully put together video. Essential watching for all engineers and Earth scientists in this field. Thank you.
This was a very helpful video. Thank you, and keep up the great work!
After 7/8 videos, you Sir have me subscribed (: Amazing content and integrated mathematical knowledge, I am very happy to have found you
Crazy good video man! You earned my sub!
Such great content, keep up the great work!
Great video - as usual. Keep up the good work.
This helped me alot with the lake Ontario flooding thx man
This is inspirational
The incidence rate is probably a good idea. We definitely had news reporters mis-explaining the 500 year flood when I was young. I think they were told it was expected to be a 100 year flood before turning out to be a 500 year flood, but I distinctly recall a news report saying the 500 year and 100 year floods overlapped as if the water worked like cicadas.
Thanks for all of the work you do for this channel, it's very interesting content.
Thanks.This is an unusually clear explanation of engineering, statistics, social risk, and law in one video. Keep at it!
Love your videos! Help me understand so many things I otherwise wouldn't.
I find your videos valuable, informative and well produced. Thanks for your efforts. Please keep it up.
Great video!
Keep doing this!!!