How Flood Tunnels Work

🥑 Simplify your dinners with code PRACTICAL16 at bit.ly/3Ws1PYm
📚 Did you know I wrote a book? There are still some signed copies left at store.practical.engineering/

I love this channel because it legit tells me about these cool civil engineering systems and areas if study I had no idea actually existed...

I think one important consideration that isn't modelled in your model is that the bottom of building basements and subway tunnels is significantly below the point where river banks overflow so even just a few centimeters above the bank can fill up whole basements.

I am a mechanical engineer and I hated my civil engineering courses in college but man do I love these videos. Keep up the great work Grady 😁

Top quality content as always! I really love the discussion of real world examples coupled with your home-made example creations! If anyone out there is wondering, Grady's book is similarly awesome!

They had to build something similar to the Tokyo system here in Dallas when they rebuilt hwy 75 during the 90s. The highway got moved from the surface down into a huge concrete canyon that can collect rainwater faster than any feasible storm drainage system could handle. There are massive underground caverns 100ft below Uptown to store it until it can be safely released into the storm drainage system (Cole Park Storm Water Detention Vault). It's so well hidden that basically no one knows it exists.

Grady, these vids are the reason you are in a league of your own. No one is able to explain in such detail from experience and have the handy-ness to build something to visualize what you are talking about. Top notch effort my man, you deserve all the success.

I know learning about infrastructure is the point, and it’s still mainly why I enjoy this channel, but I also have to say, I love the glimpses we’ve gotten of your family growing in the Hello Fresh ad segments over the years too. What a lovely little household you have, Grady!

This is the only channel that can make a 15 minute video about an underground tube, and keep me captivated from start to end.

I didn't expect a top-down view of a place I've actually walked around. Waterloo park is somewhere I visited while in Austin for university. It's quite nice! It was constructed rather recently (if I recall correctly, there's more to be added). Whoever designed it did so rather intelligently. The plant species there are native to Texas and are picked to support insect- and birdlife well throughout the entire year.

Thank you for mentioning the metric units too. It really helps 😊👍

I just love these cool well thought out solutions to problems. I find it even more fascinating that people live on top of those structures every day without even knowing about them. Stuff like this gives me back a little bit of hope in humanity every time. I mean, not nearly enough to look hopeful into the future of course, but still.

I had no idea flood tunnels existed. I knew about storm drains and tunnels, but even living in Kansas City, Missouri - which is notorious for flooding - I had never learned about flood tunnels! Thanks so much! I've learned so much from your channel, and now that I understand their functionalities, I really appreciate the infrastructure in my city so much more.

The Deep Tunnel project was recently completed in Milwaukee (in 2016?). I haven’t been in the tunnel but I have spoken to some of the engineers who have, and the photos they show are insane. Part of it is a 21’ diameter tunnel, 2 miles long, and 300’ underground. The entire system is more than just this section and can hold 521 million gallons of water in total. I just wanted to give a scale as to how big some of these diversion tunnels can get. They’re impressive structures.

Interesting, thanks. I have driven through the Kuala Lumpur SMART tunnel in Malaysia which is a multi-use tunnel allowing water and traffic movement and I believe has proven to be of great value since its commissioning.

Note that flood diversion can be done in two dimensions as well - see the Red River Floodway that diverts stormwater around the city of Winnipeg, Manitoba. It's essentially a large ditch that loops around the city to the east; if the river (flowing into the city from the south) overflows, the floodway takes the excess and returns it to the riverbed well north of the city where it can safely drain to Lake Winnipeg.

I used to laugh at civil engineering projects that always just seemed like wastes of money for city vanity projects or overbuilt solutions.
Thanks to this channel, now I get to marvel at the incredible engineering that goes into elegantly solving serious problems!

This kind of tunnel system would've been very helpful for my town a couple weeks ago. Idaho Falls, Idaho got hit with a pretty nasty thunderstorm that dropped 2 inches of rain on downtown in 30 minutes, and most of the western half of town east of the Snake River flooded pretty badly.

I trained as an Electrical Engineer (focusing on computers) but I am ALWAYS interested in how stuff works. I come at these with an eye to find some nugget of knowledge and I am never disappointed.

I've never studied anything connected to physics, engineering or else. But this channel is simply awesome. Your style is very refreshing and you always make sure everybody can understand your explanations by building those great models.
Thank you very much.

I live in the Tokyo region and immediately thought about writing a comment about the Tokyo tunnel project while watching this, then you even mentioned it! You can tour there and see it its huge in person as they need to protect the largest metro area in the world as typhoons and heavy rain is not uncommon

Grady you are magical brother, I love watching your videos and I've never given much of a fleeting thought to civil engineering projects and structures beyond list style comparisons/records/failures... But you've made it as interesting to me as any other science and I look forward to nourishing my brain with every upload. I'll rewatch your videos routinely and always wish there were a month's worth of non stop streaming. 😊

This is awesome. My dad was the District Engineer for the Corps of Engineers when San Antonio was building their tunnel. It was awesome to get lowered by a crane in a man cage down the bore and see the TBM. Very cool stuff. Thanks for the memories!

This is really interesting to see, many years ago I accompanied a group of high school students learning about local flood mitigation projects around Maitland NSW Australia (some which were completed and some which were planned or still under construction). Maitland still floods somewhat during extreme rain events but nowhere near as much as the infamous flood event of 1955 which was the catalyst for nearly 70 years of flood mitigation projects since then.

I lived in Austin during the memorial day flood in 2015, thankfully not downtown. It was insane how much that city flooded, and I was shocked as I had assumed it was too hilly and too close to the Colorado river to possibly flood like that. Good to know they build a tunnel so it (hopefully) doesn't happen again, along with them dredging the hell out of Shoal creek which is now like 15 feet below street level, and the canyon they built is as wide as it could possibly be (up to 100 feet wide in the lower areas). They also built a nice hike and bike trail along the creek in the artificial canyon, and planted as much stuff as possible. It was a fantastic place to walk the dog when I lived in downtown Austin.

The one in Tokyo is amazing. It also has many gates to prevent water coming in from the sea with pumps spitting out the flood waters. And gigantic structures where even the holes for the water to get down to the tunnel are designed to accompany the fall (at some point it's so high that the weight of the water would damage the bottom of the structure so they have this spiral/screw design to accompany the water down).

Hi Grady.
Putting a piece of wet papertowel or a wet cleaningcloth will keep your cuttingboard from slipping, making the overall cutting much safer and easier.
😊

Tokyo's underground thing is SO AMAZING if you ever take a trip to Japan you have to do a video on it because it is amazing

I appreciate you making a stormwater-related video. So many people think that stormwater goes into stormwater drains and then simply vanishes, but it is actually dealt with, with water infrastructure.

Since you talked about this, can you talk about the red river flow-way in Winnipeg? "duffs ditch". It's been described as a modern marvel of engineering and is basically just a big ditch to prevent flooding. Fargo in ND are working on something similar now.

Thank you for reminding us that there are engineers throughout the world working hard to keep us safe and make sure infrastructure benefits all. Things I've learned on your channel have helped me understand the Nova Kakhovka dam situation. Thank you for being a reassuring balance to that sad, bad news. Humans do have capacity for cruelty and destruction, but also for rebuilding, for innovation, creation, beauty and nurture. May the latter ever triumph!

Hey Grady, I'm a master's student currently studying water engineering and have been really enjoying your water-related videos. I especially appreciate the physical models you build and how detailed your explanations are. Would you consider making a video on distributed green stormwater infrastructure (GSI)? At the catchment-scale, it's a supplement to tunnels and separate storm sewers and I'd be really interested to see you do a video on it, especially if you could incorporate a model! Thanks and all the best.

Your models are always so well done! Thanks for informing us about yet another interesting piece of engineering!

As a minor note, Chicago's Tunnel and Reservoir Plan has been "done" for a while, but since the quarries they plan to use as the Reservoirs have remained active longer than was expected the final completion date has fluctuated between 2020 and 2040, depending on the economy and how much money the owners of the quarries are making.

Thanks for mentioning the TARP project in Chicago. I drive over the Thornton reservoir sometimes on I-294 and always wondered what it was. From the interstate, it looks like you are just straddling a regular rock quarry, and I thought that's all it was. Being in a semi, I get a little higher vantage point, and it's always a bit of a trip (no pun intended) crossing it. I'll have to read up more on it now that I know what it is, especially since the product I haul is a chemical used in wastewater treatment (though not for those specific facilities).

I've moved now but I remember sitting there one day with a book! I climbed somewhere that I probably wasn't supposed to be and started looking at the stuff they had built. I spent quite some time trying to figure out what that might be doing because it didn't seem like it was _only_ decorative. I had wandered over from a nearby park. Good memories :). Though I ultimately left Austin for what I feel are good reasons.

Events like flooding and structures like this seem so simple and are often taken for granted. Then I watch a video like this. Thanks for sharing. Live, learn, improve, do.

Another great video, Grady! As always, it's never as simple as it seems on the surface. I love that about pretty much every field. That there is ALWAYS more to learn, however deeply you wish to dive...the pool is certainly deep enough!

Fun seeing a civil engineering project from my home town highlighted. I saw dozens of shows in Waterloo park as a teenager and young person in Austin and didn't ever really know about this project. Even knowing some thing about the Edwards Aquifer and how the fresh water system in and around Austin works I didn't know about the flood tunnels. Mostly it was things I learned as a volunteer water quality monitor for the Colorado river - a whole team of volunteers monitor it throughout the watershed doing tests weekly or every other week (monitoring for disolved O2, nitrates, phosphates, and fecal coliform, in addition to pH and how much suspended sediments were in the river).

Another fascinating video about something I've always wondered about. Thank you for putting this together and explaining

I live near the Chicago tunnel project reservoir and it's a huge source of pride for many Chicagolanders. We can't wait to see the completed project in another decade or so. My grandparents and parents generation started it, and now we'll put the final touches on it. It's like Chicago's very own heritage project for everyone to marvel at.
And well worth the cost. It's already keeping basements and sewers from backing up during extreme rain events.
Come visit and maybe they'll give you a tour if it's dry enough!

My city (Ft. Wayne, IN) has a huge tunnel project they have been doing for a while that is meant to prevent wastewater from entering our rivers like they do now. It would be awesome to see a channel like this break it down in layman's terms. Since our local news has did a terrible job of actually explaining the project, and it's a massive job.

I have to wonder whether such tunnels are being considered here in Mississippi...or if maybe they are not feasible due to the local geology. I keep hearing that it's impossible to build simple cellars here because the water table is so close to the surface, and there's a lot of sand and clay in the soil, making for a bad combination of holding too much water and lacking stability. And yet it feels like we have the ability to overcome those problems - and with how frequently we see floods here it really seems only sensible to try!

Nice. Dallas is currently getting it's first major flood tunnel as well. The Mill Creek Drainage Relief Tunnel project started in 2018 and should be finished in 2025. It's huge. The tunnel will be 5 miles in length and be 30 to 35 feet diameter, running 100 to 150 feet underground. The intake is on the north side of downtown Dallas and the outfall is to the southeast at White Rock Creek.

I really appreciate your models! Somehow, seeing it live makes more sense than seeing it in a graphic. Perhaps I just trust the live model more than a graphic. Either way, your models are awesome!

The SMART Tunnel in Kuala Lumpur is a huge, probably one of a kind, mixed use road/flood tunnel. Used as a bi-directional dual lane road tunnel to ease congestion on the city's arterials, but when needed, it can be evacuated and used as a stormwater management tunnel. Takes about 30-60min, and then back to a road tunnel. Has been very useful for flash flooding during the rainy season.

Glad to see you mention the Chicago Deep Tunnel project! One of the biggest and craziest water management projects ever undertaken

The addition of glitter to you scale model was a cool idea! Makes its much easier to understand the flow!

You always make great videos, always informative and interesting. I'm a big fan, thank you for all that you do!

Can I just say thank you for the closed captions in your videos - these are word perfect, so I guess you produce them yourself instead of relying on AI. These help immeasurably when working with people whose first language isn't English. In addition, your pronunciation is clear and you don't use too many collquial expression - some for interest - but not so many as to be obscure.

In my home city of Wichita we were fortunate enough to get around to solving this problem when the city was still quite young. Therefore we have an absolutely massive trench that bypasses the city core and parallels I-235, and has proven its worth many times. It was also substantially overbuilt - which has come in handy somewhat recently.

If you haven't already, I'd recommend you to take a look at the Dutch "waterschappen" which manages the water levels in all the ditches across the country, they preserve the water in the hot summers, and carefully control the water levels to prevent floods without flood tunnels. They also keep the water levels in peat areas (like in the area around the AirPort of Schiphol) extraordinary high to keep the peat from sinking or something like that

Excellent content. I'm curious if you could do some episodes on NYC and their flood protection measures since Sandy. What they are doing about the city sinking under the weight of all the skyscrapers?

I worked at a facility that had a hazardous waste treatment plant that was essentially a big distillery. There are several one million gallon tanks in the tank farm and they rest in a very large steel containment basin.. During monsoons the large catch basin will collect a lot of rain water which tends to be collected back into the tanks to be processed which is expensive, so they do a lot of testing to make sure the water that's caught from the rains is safe, and then pumps it out onto the desert floor.

The sparkly water in the demo is so cool and pretty! It makes it easy to see the flow and turbulence too. Thanks for the video :)

I'm so glad that I have an option to learn cool things about infrastructure and such things! Thanks Grady.😊
Also I bought your book but it isn't as easy for me to read it as I had hoped, But I like it and am continuing to read it!

The funny thing is surface bypasses are often chosen around the world. Basically what you describe at 3:50. In the 1700s to 1900s, many times a European city got flooded and city officials took land from destroyed buildings (usually compensating the owners... most of the time) and used them as bypass. This was especially common among the Danube, Vienna has a hole story on that. Anyways basically the destruction freed up the surface required for option 3.

I'd love to learn about a deep tunnel system like Milwaukee has implemented. Different purposes, but both tunnels for tons of water!

Houston needs the bayou tunnels more than anything! Great video! Never knew about the system in Austin. This is such a good explanation and visual representation 👌🙏

This is what the city of Tallahassee used to curb flooding with Cascades Park. They used huge precast reinforced concrete tunnel segments to create an underground river with small lakes along the way. This goes thru miles of downtown and between the universities.

educational and approachable, as always. thank you! i would love to see a mini follow-up that highlighted flood management with arroyos and other ground-level techniques.

Have a look at Malaysia's SMART tunnel. It's an excellent example of a multi-use flood tunnel. Really awesome!

A couple of weeks ago, my city experienced 85% of our annual average rainfall in one day. Obviously we weren't prepared for something like that, and the street drains were flooded until the next morning. Part of me wishes we had these flood tunnels to deal with that...😅

I wish more people appreciate how much thought, time, effort, blood, swear, tears, engineering, and adaptations lie mere meters under our feet at any given moment.

Grady, thanks you for your amazing work. Today in 2 am local time Russian forces exploded The New Kakhovka dam in sothern Ukraine. It would be very interesting to see you cover of this topic from engineer point of view.

Thank you for bringing up some international examples. This greatly improves on the usual US focused view in those kinds of videos. Keep up the good work. Greetings from Austria.

You have a great channel and put out awesome, simple to understand concepts that makes people smarter about how the world around them works and why we pay taxes. Keep up the good work!

The fact that you have over 3m followers and your video gets 500k views in 24 hours gives me hope for the world. Keep up the great work!

Excellent video, perfect example of the flood tunnel process. Very informative!

I walk around my city now and see things I never paid attention to because of this channel.
So many interesting things to figure out what they do out there!

I was able to look at the RiverWalk in person some years ago. Was a pretty impressive feat of civil engineering.

So, I thought i would mention that I do like the content very much. Your knowledge and delivery are great. Then there are you models. I understood the whole tunnel thing even though i never knew the existed before. then you whip out a model. Your models are awesome. Thanks for sharing your love for what you do.

Grady that was very interesting. If you are not aware, Lake Ray Hubbard that connects Garland to Rockwall in the Dallas area is in the midst of a huge new construction of several more bridge lanes across the water. Also I-30 is being widened and will divide the flow of traffic before it reaches the lake. Would love it if you would like to comment on that as it appears very interesting. They have boats with huge cranes on them

Just sharing. Thought you might be interested in Malaysia’s SMART tunnel project. A flood tunnel that doubles as a city expressway when it’s dry, and when half-used. But when fully utilised, it closes the expressway portion and turned it into a temporary reservoir and tunnel to channel upriver flow down to another part of the city, to divert waters from major parts of the city. Although it has not prevented certain floods in the city of KL, it has actually prevented the most major ones that had happened in the past that as one consequent actually moved an arts theatre to a dedicated location in the present day. The SMART tunnel is still worth mentioning, as it’s so far the only one that most would be aware of that sees a flood tunnel doubles as an expressway under the city. Thought it might be an interesting piece of information, for those unaware of its existence.

San Antonio actually has a few of these systems in place across the city. There is the River Walk system that protects downtown and a new system that was built in the last few years on the west side between Lackland and Kelly Field down Military Dr. When I lived in downtown SA on the River Walk after several months of walking it every night with my dogs I heard about the history of its beginning and the flood tunnel that was added in the 80’s. Was mind blown to think about all of the systems that are in place that are multipurpose for everyday use, specifically the lock system along the River Walk, which I thought was just for the river barges at the time but in fact was part of the entire flood mitigation system for downtown.

I appreciate your effort you put into all these models in your garage.
I like that they put a little waterfall on that station

This is a great video on the topic of lifesaving flood tunnels. It's only slightly aggravating our cities need these massive costly pieces of infrastructure that go unused 99% of the time instead of putting in the work to incorporate as much permeable surfaces as possible and doing analysis on what elevations and places we can and can't build enclosed structures. There must be a way to shape a society around nature as opposed to forcing nature to bend to our will

Fantastic video! I would love a more detailed video of the concept of sponge cities.

Grady: thank you. Not only do I learn so much from you, but I love infrastructure especially water infrastructure.

I always love learning more about the geology and engineering of our town. 😀

I work in a utility company which is constructing flood tunnels. The tunnels will serve as a buffer leading the water into reservoirs, parks or open fields. The capacity is calcutated to be big enough to carry one flood/heavy rainfall. After the cloudburst is over the water is pumped back into the normal system at a manageable rate and treated at the wastewater plant.

In Cleveland, our combined storm/sewer used to discharge untreated water directly into Lake Erie like 50 times a year. Overflows are much rarer now, down to like just a couple times a year, but it's still an issue.

I visited the flood tunnels of Tokyo that you showed in the video. Quite an impressive structure

I really really hope well implemented flood management, and surface- and groundwater stuff will get more focus in Cities Skylines 2.

Love your videos, and also live in CTX! Would love a little insight into why basements are so rare around here :)

New Castle, Indiana, decided to combine storm and septic sewers to save money. That worked well for people at the top of the hill. During a storm, the results for the people at the bottom was somewhat different. An elementary school was across the street from a house I was working on. My dad had been there months earlier during a storm, and told me the results. First, you could see water and other sewage related items start to dribble out of the finger holes on the manhole cover. Then the surge hit and Mount Crapatoa exploded, sending the cover flying and spraying sewage over the elementary school playground. When I was there, I discovered that the solution was to weld the cover down. I saw the street lift several inches, and plumes of sewage almost 20 feet. But think of the money they saved by putting storm and septic sewers together, especially the money saved by shutting down the elementary school playground and repairing the road a couple of times a year. Eventually the elementary school was turned into an adult education center, because it's OK if adults get violently ill after using the playground.

Grady, A while ago a local rural property owner sued the township for damages incurred from flooding. They had built their home at the fork of two small streams and expected the authorities to eliminate the problem of flooding during periods of high rainfall. They complained that this happened every year during the spring rainy season. Is there an engineering solution to gross stupidity ?
As someone who has always enjoyed learning how things are done and why they are how they are, I love your explanations. Thanks !

Grady thanks for your great videos! With the help of your videos, i started to be interested in infrastructure. And in October, i will start to study the subject infrastructure and environment. And all because of your great videos. So thank you for your videos and your great book. Greetings from Germany!

Well, you've done Austin, but I would love to see a video on Houston and how it deals with flooding (I mean.. when we can), but also how the roads are designed to carry water because we're so close to sea level.

As a person who lives in Vienna, I suggest you have a look how we figured out to manage floods from the danube river... ;)

Great video, when you talked about the combined sewer it reminded me of my mom, who works for the Cleveland sewer district. I don't know many of the details but I think that dealing with storm water is a major problem and project at their treatment plant. Her work has always been of interest to me and you help teach me the stuff about her work that I would never even think to ask about, keep up the great work. Also, is there any method in development to separate storm water and sewer at the treatment plant in a system with combined sewer?
Edit: I just remembered that their shirts and their merch of sorts generally has the text "I (Heart emoji) (A simple graph of water)" and I have so many things littered in my room. Its multiple shirts and draw string bags that are all this same blue color

I had to work on-site at the outlet of the Waller creek project before it was finished. A massive flood in lady bird lake flooded the site before the equipment to be moved out. It was a massive mess. Couldn’t believe how deep that tunnel went down.

Excellent content, wonderful practical demonstration using effective models. Watching the cutting board float and slide ontop of the ceramic stove top while you were cutting green onions scared me a little. I am sure you may already know this, but if you put a damp towel or cloth underneath the cutting board it will help secure it. I would like you to keep full functionality of your digits so that I may benefit from all of your wonderful videos! All the best, and keep up the great work!

It's always a good day when Grady builds a model.

1:33 I always say that too! The only thing cooler than a huge tunnel is a huge tunnel that carries lots of water and protects us from floods. (But really though, water infrastructure is really cool)

The largest system like this I designed was about 10 metres wide, 3m tall and 1.5km in length utilising rcc, this must’ve been a massive feat.

Excellent video Grady! You make learning fun!

3:50: While constructing a bypass through a downtown is economically infeasible due to all the high land values, if you think larger you can bypass the entire downtown (not just through it). This is what Sacramento did with the Yolo Bypass: construct/designate a flood plain on the outskirts of the City that the Sacramento River is diverted into during peak flows. This past winter (one of the wettest in recent memory), the Bypass looked more like a lake with several feet of standing water. But this was better than the alternative - overtopped levies and flooded urban areas (downtown and environs).

With the hello fresh sponsorships this channel has become both an engineering channel and a food channel. Now we need a video about the infrastructure that goes into growing food

The Tokyo system is also used for filming impressive spaces in live action works, and has even been used as reference for locations in animated science fiction and fantasy. Assuming they collect some fees from that along with tour admissions, they can get at least a trickle of revenue (pun intended) while generating civic pride in their impressive achievement.