Live data from Hacker News

New York Underground

nationalgeographic.com

11–20 of 87 posts

Re: New York Underground

#14
post #2

The to scale version is better: http://www.nationalgeographic.com/nyunderground/docs/scale.h...

Woah. The water mains are 800 feet down? How does that work? How did they even get there?

I'm guessing they probably got there before everything on top was built, but how do they get down there now for repairs and such?

Re: New York Underground

#15
post #2

The to scale version is better: http://www.nationalgeographic.com/nyunderground/docs/scale.h...

Woah. The water mains are 800 feet down? How does that work? How did they even get there?

It's closer to an underground version of an aqueduct than to a normal water main, a long-distance tunnel being bored to bring water from upstate reservoirs: http://en.wikipedia.org/wiki/New_York_City_Water_Tunnel_No._...

I'm not 100% sure why it's that deep (and can't seem to find a solid explanation). What I can glean suggests that it's partly due to wanting it to be in more geologically stable bedrock that passes below any bodies of water and geological aberrations in the area. And partly so that it can be fed by gravity along a continual downwards slope, which causes it to be fairly deep by the end (then at the end the tunnel narrows, increasing pressure sufficiently to push water up a vertical shaft to the surface distribution network).

Re: New York Underground

#16
I'm no civil engineer, but why are the sewage tunnels above the clean water tunnels? If there were a leak, wouldn't the sewage seep into the clean water? Or is the clay thick enough to provide a good barrier?

Re: New York Underground

#18

I'm no civil engineer, but why are the sewage tunnels above the clean water tunnels? If there were a leak, wouldn't the sewage seep into the clean water? Or is the clay thick enough to provide a good barrier?

I feel safer about it when looking at the scaled version: http://www.nationalgeographic.com/nyunderground/docs/scale.h...

Re: New York Underground

#20
The greatest depth shown in that graphic is 800 feet. At 10-12 feet per floor, that's equal to the height of a 67-80 story skyscraper. This means Manhattan has a 'mirror-image' city under the ground -- its 'citizens' are electric power, water, gas, and trash.

I can't help but be in awe.

Post reply on HN