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?
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]
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.
Wild to think this is the same project featured in the third Die Hard, which turned 30 this year.
Should they ever reboot Die Hard; it'll need a sequence involving CA HSR infrastructure.
Die Hard: The most expensive mile
The project started in 1954. A 70 year old project.
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?
...
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.
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.
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...
Those are… actually some very good questions.
They finally got Water Tunnel #3 close to completion? Work was stopped a decade or so ago, but apparently it was restarted.
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.