Comment by bilbo0s | Hacker News Reader

Comment by bilbo0s | Hacker News Reader

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???

Um, sabotaging any city's water tunnels would make the city uninhabitable for years.

Most frightening experience I ever had as engineer in my life:

I was intern. At a place in a midwestern city where a city's water infrastructure can be monitored. Long story short, I heard "PING". Then three more "PING"s. Then another "PING". Then 2 more. Even as an idiot intern, I knew what the implications were with respect to tensioned concrete. I was thinking in my head, "8 feet diameter. 96 inches." But I couldn't remember the PSI because I probably had already soiled myself. Thankfully there was a grey beard there who coolly looked over at me and said, "Probably want to start shutting that down son."

2 things I learned. Calm is contagious. And our infrastructure is way more frail than should be the case.

Shutting what down? Anyway, terrifying.

But NYC has a rather high level of vulnerability with a small number of choke points (there are currently only two water tunnels for the entire NYC metro area), but yes, the water infrastructure for a lot of major cities could be disrupted disturbingly easily.

> there are currently only two water tunnels for the entire NYC metro area

How are you counting this? If you mean Hudson River crossings between NJ and Manhattan, there are five: two road tunnel groups (Holland and Lincoln) and three rail grops (Upper/Lower Hudson and North River). When Gateway is complete (2030s), there will be four rail groups.

But if you mean the entire NYC metro area, there are significantly more: Manhattan <-> Brooklyn alone has the Hugh L. Carey for road traffic, and then six active subway tunnel groups. Manhattan <-> Queens has a similar number.

This is in reference to the 2 tunnels that supply water to the NYC metro area.

Thanks, I misread that. Although technically there are three operational water tunnels for NYC :-) — tunnel #3 is operational despite being under construction.

What does ping mean?

There are steel wires inside the concrete that holds the structure, and when they are about to break, they start to crackle ("ping").

https://youtu.be/RMZW1SX_rbk?t=48

Uh, how about a spoiler alert? Linking to the end ruined the first 75 seconds for me.

> "Probably want to start shutting that down son."

Can totally picture

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