Big_Tunnel + Limestone + Acid_Rain =:= Oh_Shit

Ever hear of something called The Delaware Aqueduct?

Yeah, I guessed not.

Its an 85 mile long set of three tunnels in New York connecting the Rondout Reservoir in Ulster county, through the West Branch Reservoir in Putnam county, and ending up in the Hillview reservoir in Yonkers.

Or, for those of you who aren't from New York (or the U.S.), it basically takes water from a reservoir on that side of the Hudson river, and brings it over to New York city, which is on this side of the Hudson river.
See, the thing is, there is this area called The Catskill/Delaware Watershed, which gets a lot of rain.  A ton of rain.  So much rain that, well, its got more water than you can shake many sticks at.  As a result, in the early 20th century, they started building reservoirs there to collect water for New York City which uses that self-same ton of water for all sorts of water-y purposes. 

Technically, there are three reservoirs there at Neversink, Ashokan, Schoharie, Pepacton, and Cannonsville, but if you really want to know more, go hit up Wikipedia.  For our purposes, water from Cannonsville, Pepacton, and Neversink all end up going through a bunch of tunnels, and end up in the Rondout Reservoir, and that, my friends, is where the fun begins. 
The Delaware Aqueduct that I mentioned earlier is a tunnel that takes water from the Rondout reservoir - which is 840 ft. above sea level, and goes waaay down (sometimes almost 1500 feet below sea level), beore making it to the West Branch reservoir.  Its huge, huge, being almost 14 ft. wide, and carrying about 1.3 billion gallons of water per day.  Which, by any measurement, is a lot of water.  Oh, by the way, thats almost exactly half the water used by New York City every day.

And there, my friends, lies a tale.  Y'see, its got a tiny leak in it, losing about 35 million gallons of water every day.  Ok, maybe thats not a tiny leak.  Its the BFG of leaks (a BFL?). 
What happened is that way back when they build this tunnel back in the early 1940s, nobody had ever heard of acid rain.  So they just dug and dug, and when they hit this huge patch of limestone, they just dug right through it.
Y'know what limestone is, right?  Basically calcium carbonate.  And acid rain is, well, acidic. You mix the two together, and the limestone basically just dissolves.  Heres a nice video that points this out since a video is worth 1000**2 words.

So our brave tunnel diggers sent all that water from the Catskills surging through limestone, which has - oh so helpfully and valiantly - dissolved and sprung innumerable growing leaks with no end in sight. Just imagine 35 million gallons of water suddenly showing up underground.  Every day.  No end in sight.  Not too helpful to anything built above it, e.g. Warwasing county.

The thing is, it isn't trivial to fix this.  The height differential in the tunnel reaches up to almost 2400 ft, which means that this hosepipe is under an enormous amount of pressure, which means that its basically not feasible to work in the tunnel.  If you somehow managed to be in there, you'd be squashed flat in, well, no time flat.  Imagine scuba diving at 2500ft.  One...Just...Doesn't. (Ok, technically one *does* at 600 ft to check some of the shallower areas, but lets just leave it at that)

So, enter alternative plan B, which is to dig a second tunnel, and basically shut this tunnel down (and oh, not have the second tunnel go through limestone).  
Its supposed to be three miles long, and goes from Newburgh on the left to Wappinger on the right.  Once done, they'll hook it up to the aqueduct, and shut down the old tunnel - which will be tricky in and as of itself...
Building it is going to be tricky too, since people will be working at depth - breathing helium, protecting against the bends, oh it'll not be a day in the park thats for sure.
And finally, they're going to start this next year, spend a ton of money ($1.2 billion, sure to rise), and end in 2017.

So, whats the point behind all this?
Thanks to budgetary issues, they've shelved this project.  Oh, they might eventually get it back on track, but who knows when.  And the thing is, this is exactly the type of project that qualifies as Really Really Useful Infrastructure Spending.  Its not a Bridge To Nowhere.  Its not Yet Another NFL Stadium Funded By The Public.  And its really, really, not some kind of vanity public sculpture. 


Sigh.  The problem with infrastructure is that we lump it all into the same bucket, and consequently, all the good stuff (like this) ends up getting tarred with the same brush as the idiotic crap.

I weep for our country...