62 years in the making: NYC's newest water tunnel nears the finish line

147 pointsposted a month ago
by eatonphil

73 Comments

aizk

a month ago

It's amusing to me watching devs talk about the breakneck pace of AI and LLMS, AGI all that sorts of stuff, what that wild future will give us - when there are far, far more difficult problems that lie directly in front of us, mainly getting public infrastructure projects done in normal spans of time, or hell, getting them done at all.

BurningFrog

a month ago

The problems with getting public infrastructure projects done in time or at all are political, not technical.

There typically are no technical solutions to rhose.

awesome_dude

a month ago

Kind of - the art of fortune telling plays a big part in things

It's not needed now, but we think that it will be needed in the future

It's needed now, but we don't know if we will use it in the future

How MUCH will it be needed in the future

Will there be a future technology that makes this investment unnecessary, or even obselete before the project ever completes

For the latter, a big argument of "No need to invest in commuter trains" argument was "self driving cars are 'just around the corner' and they will make mass transit a quaint thing of the past" was used to deny investment in trains.

rayiner

a month ago

> For the latter, a big argument of "No need to invest in commuter trains" argument was "self driving cars are 'just around the corner' and they will make mass transit a quaint thing of the past" was used to deny investment in trains.

People don’t want to invest in trains because Americans don’t like trains. We have only one real city, and that city’s population consistently has net domestic outmigration. The city’s population is kept stable by a steady supply of international migrants: https://www.cityandstateny.com/media/ckeditor-uploads/2025/0....

Most Americans don’t want to commute sitting next to strangers. It’s not complicated.

teleforce

a month ago

>There typically are no technical solutions to rhose.

Not that they can't, but they won't.

cwillu

a month ago

Yes, that's what a political problem is.

programjames

a month ago

There typically are, but sometimes the technical solution is bad for those in power, or they're unaware of it, or it hasn't been discovered yet.

8bitsrule

a month ago

If empirical observation is 'technical', then keen eyes can spot the grifters before they can be elected or corrupt the already-elected. Then we just need the will to permanently deter them.

pclmulqdq

a month ago

AGI is easier than getting New York City to complete an infrastructure project in less than a decade or less than a billion dollars.

The corruption and graft run so deep you would have to literally murder a lot of people to get that to happen.

woodruffw

a month ago

Call me crazy, but I don't think $6B for a 60-mile, deep-bore tunnel through the densest urban core in the US is that much money.

user

a month ago

[deleted]

mmooss

a month ago

What indication do you have that the construction time for tunnel 3 is due to corruption or even that it's taking longer than necessary? It seems like a very large engineering project; sometimes those take time.

bee_rider

a month ago

Yeah, I have no idea how long a tunnel of this size is supposed to take, and I’m surprised if many people here do.

It’s a big project, and it is tricky to patch it after release. The thing is supposed to last 300 years, and usually we use infrastructure well past it’s intended lifespan…

zdragnar

a month ago

Google claims the original build was supposed to take 50 years, and it will take 62 due to delays from a funding crisis before de blasio.

However, this is only the second phase of the plan, with two more phases broken out into separate projects. I've no idea if those were supposed to be a part of the original 50 year timeline or not.

deaux

a month ago

> What indication do you have that the construction time for tunnel 3 is due to corruption or even that it's taking longer than necessary?

These two questions are casually put next to each other in the same sentence but they're incredibly different. Personally, I don't think that corruption is a significant factor in how long it took. The second question is way too leading/framed - "necessary" doesn't exist past the physical limits.

For example, would the same project have taken the same time in China? No. Does that mean it should've taken as long as it would've in China, as clearly it took longer "than necessary"? Not by definition.

rayiner

a month ago

Why is NYC so corrupt when large cities like London, Munich, and even Paris are much less so?

mmooss

a month ago

Why do people say NYC is more corrupt? I don't know of evidence or reports. To me, it doesn't seem more or less corrupt than other major cities in the US. It's hard to compare to other countries, where city government may have different roles.

Certainly NY's government and budget are larger than other US cities, for obvious reasons.

cyberax

a month ago

They are just as corrupt and/or incompetent. Have you tried Deutsche Bahn recently?

EdwardDiego

a month ago

If you think Munich isn't corrupt, you should ask a Münchner - hell, their airport is named after a corrupt politician. [0]

But as a few Germans have put it to me - sure, there's corruption here, but at least it still gets things built unlike _Italian_ corruption.

Which is an... ...interesting point of view.

[0]: https://en.wikipedia.org/wiki/Franz_Josef_Strauss

As for London, they built an entire industry around hiding money for oligarchs who stole it from their own countries. Maybe it's technically legal, but it's morally corrupt AF.

aizk

a month ago

Yes. That's exactly my point.

arjie

a month ago

That is true. In fact it relates to one of current America's greatest truths: coordination problems here are much more difficult than many technological problems. This is what makes many of those "oh so you take those autonomous vehicles, put them on a track for efficiency reasons, then link them together so they can transport more people, and voila! you have a train!" comments ring hollow.

Building a train requires coordination. Building an autonomous vehicle requires technological innovation and convincing a few people at the top levels of government. The specifics matter (and the Abundance guys have done a great job summarizing them) but it's due to an entrenchment of certain styles of laws.

So the answer to "why do Americans build self-driving cars to ease transport when Europeans just built subway systems?" is "we do these things not because they are hard, but because they're actually much easier than the other thing you find easy".

llbbdd

a month ago

The other answer is that Europe is tiny and subways are almost useless in America unless you are exceptionally poor

user

a month ago

[deleted]

potato3732842

a month ago

The "problem" here isn't the construction of a tunnel. It's the political reality of the people on top of it.

bongodongobob

a month ago

You have to deal with directly affecting real estate owners, potentially 100s of thousands of different ones in NYC. Not to mention 100s of years of underground infra and all the different companies that own that stuff without cutting service to anyone. It's insanely difficult and I'm not sure I understand why you think it wouldn't be.

aizk

a month ago

You're missing what I'm saying. I'm poking fun at devs that think AGI will magically solve all our problems - they have no idea just how insanely complicated physical infrastructure is.

bongodongobob

a month ago

I could definitely see it helping in this space though. I was a project manager for a telco for a bit and there's lots of data in different formats and systems that even today's AI would be great at splicing it all together for one coherent picture.

tsunamifury

a month ago

Haha the technical difficulty is not the hold up here sweet summer child

ChickeNES

a month ago

Wild to think this is the same project featured in the third Die Hard, which turned 30 this year.

linksnapzz

a month ago

Should they ever reboot Die Hard; it'll need a sequence involving CA HSR infrastructure.

wtvanhest

a month ago

Die Hard: The most expensive mile

rayiner

a month ago

They need to do a post-apocalyptic movie with a scene set in Fresno with unfinished CA HSR viaducts hulking in the background against a polluted orange sky.

linksnapzz

a month ago

The problem with post-apocalyptic films set in Fresno is that the local audience will be challenged to find things depicted that are different, nevermind worse.

cogman10

a month ago

The project started in 1954. A 70 year old project.

jeffwask

a month ago

I was just going to ask is this the tunnel from Die Hard, so cool.

mvkel

a month ago

Die Hard: The Way of Water

jmyeet

a month ago

If you ever want to put the cost of something into context, remember that Mark Zuckerberg spent $77 billion on the Metaverse.

I went looking for an article I read a decade ago about the challenges of supplying water to NYC and maintaining the aging infrastructure. Part of the "race" to build new capacity is so they can actually turn off some of this supply for extended periods to repair it. Millions of gallons of water leaks or is just unaccounted for every day.

I didn't find it but this [1] kind of goes into it.

And since you can't turn the water off (generally), you need to do repairs in fairly extreme environments and use materials that don't corrode over very long periods of time. IIRC some pump or valve infrastructure was made out of manganese bronze for this purpose.

[1]: https://nysfocus.com/2024/11/27/new-york-water-leaks-drought

rangestransform

a month ago

Mark's money is sucked up from the entire world, whereas NYC's money is picked from the pockets of NYC residents, obviously I'd prefer one over the other given I live in NYC

xnx

a month ago

> remember that Mark Zuckerberg spent $77 billion on the Metaverse.

I'll never be a billionaire, but I'll also never spend $77 billion with so little to show for it.

Animats

a month ago

They finally got Water Tunnel #3 close to completion? Work was stopped a decade or so ago, but apparently it was restarted.

toomuchtodo

a month ago

Still a bit more to go. Hopefully they offer some tours of the final phase before it’s flooded and no longer accessible for decades.

> The Bronx and Manhattan already receive water from it, and the final phase — extending service to Brooklyn and Queens — is expected to be completed by 2032.

senordevnyc

a month ago

I live in NYC, and I'd love a tour like this. Are there other of these kinds of civil engineering tours out there?

toomuchtodo

a month ago

The one that made me think of this is Metropolitan Area Outer Underground Discharge Channel in Kasukabe, but I’m sure there are others. If you find a list of civil engineering tours available, please share!

Tokyo Metropolitan Area Outer Underground Discharge Channe - https://news.ycombinator.com/item?id=43816183 - April 2025 (6 comments)

Tokyo's Underground Discharge Channel - https://news.ycombinator.com/item?id=19785044 - May 2019 (40 comments)

Tokyo Is Preparing for Floods ‘Beyond Anything We’ve Seen’ - https://news.ycombinator.com/item?id=15436943 - October 2017 (210 comments)

mmooss

a month ago

So many questions ... which probably have been asked on prior HN threads ...

I wonder why 800 feet underground: Is that necessary to pass beneath all other infrastructure (to prevent flooding it?)? Remain beneath waterline to create negative pressure and reduce leaking? ?

Also, what is the general mathematical relationship between depth, rock pressure / weight, and energy required to drill? That is, what is the proportion of energy required to drill beneath 800 feet of material compared to drilling beneath 400 feet?

...

cap11235

a month ago

I don't know about New York in particular, but Chicago water engineering seems a related topic.

Here you do deep tunnels to avoid the surface, in ways another poster said; everything is easier when nothing is in the way.

For the mathematical difference, 400 feet below sea level and 800 feet below are almost exactly the same: difficulties are water getting in to your pit, but the machines that work on rock, work on rock at the same speed regardless of depth, so the difference between 400 feet and 800 feet is best described as 400 feet difference. A big issue here is that they do not drill; they hammer. Pounding base pylons into bedrock causes dramatic rhythms in the surrounding 500m, but that's to deal with the bedrock, not depth.

xnx

a month ago

> A big issue here is that they do not drill; they hammer. Pounding base pylons into bedrock causes

What? I've never heard this. Everything I've read says pylons go into drilled holes.

Spooky23

a month ago

The depth allows it to be drilled through bedrock, which avoids a bunch of complications on an already complicated project.

This thing will probably be operating hundreds of years from now. What a project.

cogman10

a month ago

It's a 60 mile long tunnel and in order for water to flow through it, you need either pumps or a downhill gradient.

I'd guess the reason for the 800 ft is because the reservoir it'll draw from is near sea level.

nuccy

a month ago

Rivers (e.g. Mississipi) work with much smaller gradient of just 0.01% [1], while with your assumption it would be 0.25%, so 25x.

Maybe instead it needs to pass under the rivers [2: cross-section] surrounding New-York, which may be much deeper, especially when it comes closer to the bay passing Queens and Brooklyn [2: map]

1. https://en.wikipedia.org/wiki/Mississippi_River

2. https://gordonsurbanmorphology.wordpress.com/2014/10/26/wate...

woodruffw

a month ago

This piqued my interest, so I checked: Tunnel #3 passes under the Harlem River and then the East River, but the Harlem River is less than 30 feet deep for the most part and the East River is around 40 feet deep at the most.

(The Army Corps of Engineers has great detailed depth surveys for most of NY's waterways[1].)

Edit: There's also a higher-resolution render of the tunnel layout here[2].

[1]: https://www.nan.usace.army.mil/Missions/Navigation/Controlli...

[2]: https://extapps.dec.ny.gov/docs/water_pdf/nycsystem.pdf

woodruffw

a month ago

> I'd guess the reason for the 800 ft is because the reservoir it'll draw from is near sea level.

I believe Tunnel #3 connects to the Catskill Aqueduct[1], which draws from the Schoharie and Ashokan reservoirs. Both are at least a few hundred feet above sea level (the Ashokan is about 600 feet above, since it was formed by flooding a valley in the Catskills).

But I have no idea why they dug it so deep, given that! Maybe to give themselves an (extremely) ample buffer for any future infrastructure in Manhattan.

maxerickson

a month ago

The average depth is more like 400 feet.

One diagram I saw indicated 2 different layers of bedrock. I didn't find anything real clear, but it can be that the lower layer is a more suitable material for the tunnel.

SoftTalker

a month ago

The tunnel is a pipe, as long as the tunnel and exit end is lower than the entrance end, water will flow without pumps. Unlike an aquaduct, it doesn't need to be on a continual downward gradient from one end to the other.

cyberax

a month ago

> Also, what is the general mathematical relationship between depth, rock pressure / weight, and energy required to drill?

There isn't any. It completely depends on the local geology.

Liquids are easy because there are no lateral load transfers, and the structures have to bear the weight of the entire water column above them. But with soil you get lateral load transfer, so the pressure on the tunnel is not easily relatable to its depth.

That's also why you can have mines that are kilometers deep, yet with tunnels held by wooden beams.

KaiserPro

a month ago

> energy required to drill

That depends on the rock type. In london, most things are clay, so not actually that solid (ie it needs shoring up immediately, and will collapse without supports, hence the travelling shield)

manhattan schist appears to be reasonably hard (not granite, but also no clay)

7thpower

a month ago

Those are… actually some very good questions.

zhivota

a month ago

My immediate thought is at what point does desalination tech + clean energy reach the crossover where building a 60 mile tunnel over 60 years not make sense?

It feels like very soon, and coastal cities can stop relying on hinterland reservoirs for water.

PLenz

a month ago

Probably never. The tunnels cost a lot to build but, once built run almost for free - they're powered by gravity and will keep running for close to a century before major maintained is needed.

zhivota

a month ago

Yeah that makes sense but if growth dictates another tunnel... And it takes another 60 years, your capital expense starts to look a lot like an operating expense. Not to mention one of the big stated purposes of this tunnel is actually to facilitate maintenance of the other tunnels. There is probably more operation cost hidden here than seems obvious.

cguess

a month ago

The big reason for tunnel 3 isn't new population growth, it's so that the other tunnels can be shut down for maintenance and inspection. NYC's population is more or less stable over the last 90 years.

margalabargala

a month ago

Close to a century?

There are Roman aqueducts in continuous operation for two millenia.

llbbdd

a month ago

AFAIK there is one still in operation and entirely for tourist purposes

patmorgan23

a month ago

Capital vs operating is a big factor here. The tunnels operations & maintenance cost is probably far lower than a desalinization plant that could produce an equivalent volume of potable water.

Ericson2314

a month ago

Desalination will be a West Coast thing. The East Coast has abundant fresh water.

youarentrightjr

a month ago

> Desalination will be a West Coast thing. The East Coast has abundant fresh water.

It's not entirely accurate to say that the West Coast doesn't have enough fresh water. Oregon and Washington have a lot of rain, and many groundwater resources.

California kneecaps itself with perpetual deeded water rights and mismanagement/closure/lack of improvement to reservoirs and related infrastructure. There's a long history of this kind of stuff in the state (see the watering LA desert, the Salton Sea experiment, and many others).

mattmaroon

a month ago

It’s probably more likely AI will become sentient and kill us than it is desalination and clean energy are cheaper than this.

This was only a 60 year project because of politics.

user

a month ago

[deleted]

larusso

a month ago

Is that the same project shown in Die Hard 3? Where the truck driver enumerates the progress etc?

user

a month ago

[deleted]