Speaking of blow-down

This structure on the East shore of the Hudson River a few miles south of Newburgh, NY houses the blow-down valve for the Catskill Aqueduct.

If you look at page 28 of this book you can see a cross section of the tunneling at that location.

The blow-down was intended to be used to drain the aqueduct should internal maintenance ever be required. However the engineers are afraid now that if the internal pressure is relieved portions of the aqueduct would collapse.

If you click the "PDF" in the upper right of the page you can download the entire book. It will be my reading for the next few days.

 

[metengr]

Hope you have a large supply of bottled water.

 

[MikeHalloran]

Fascinating book.
Thanks.


Mike Halloran
Pembroke Pines, FL, USA

 

[zdas04]

With that cross section I wouldn't drain a 100 year old 14-inch pipe either. If I'm reading the cross section right, they went down to 1110 ft to cross the Hudson River. With a water gradient the external pressure is nearly 500 psig. Since it is under a river, the gradient could be a gravel pressure gradient which could increase that number to over 2000 psig. I've seen a lot less external pressure make modern 36" steel pipe look like a beer can under a Semi.

David

 

[MintJulep]

It's 14 feet, not 14 inches.

 

[zdas04]

Even better. I'd be terrified.

David

 

[ivymike]

so... sleeve it somehow?

 

[unclesyd]

The crossing the Hudson is in solid Granite, supposedly under enough Granite to take the pressure.
I've seen several shows on various Discovery TV where they are driving two new tunnels.

I would like to see a pay scale for the workers, including engineers, at the time.

 

[MintJulep]

Those new tunnels are under Manhattan for distribution. No new supply tunnels in the works that I know of.

 

[unclesyd]

MintJulep
You are correct when I remembered the programs the vertical shaft entrance was between a lot of building. I called a buddy who works for NYPA and he confirmed what you posted.
He stated that at one time they were looking to move some people from the NYPA to the tunnels, his comment was what does inspecting bridges have in common with tunnel inspection.

 

[VEBill]

I saw a documentary on the new "Tunnel No. 3".

Wiki: "It is intended to provide the city with a critical third connection to its Upstate New York water supply system. The tunnel will eventually be more than 60 miles (97 km) long. Construction on the tunnel began in 1970 but is not expected to be completed until at least 2020."

The documentary mentioned the inability to service the old tunnels and it implied that No. 3 was being built to address that problem.

 

[BigH]

Must be dense today - but I can't find any "pdf" button to click . . .

 

[ScottyUK]

I couldn't either.


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If we learn from our mistakes I'm getting a great education!

 

[zdas04]

It is on the same lline as the zoom buttons all the way to the right, just to the right of "Feedback" (your screens may be cutting the last few columns off).

David

 

[MikeyP]

I don't see the zoom buttons or "Feedback" either. Perhaps the copyright restrictions mean it is only available in certain countries?

M

--
Dr Michael F Platten

 

[waross]

I ran eventually into this:

It looks like you're located outside of the United States. Although you're welcome to read about Google eBooks, please note that Google eBooks are only available for sale to customers in the U.S. at this time.

Bill
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"Why not the best?"
Jimmy Carter