4 ms·
> 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], whi
by woodruffw 10mo 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 10mo agoThe 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.
- woodruffw 10mo agoYeah, that's certainly possible for Brooklyn and Queens. Manhattan and The Bronx have very shallow bedrock, but Brooklyn and Queens have lots of clay, sand, and silt.