How Do You Fix a 45-Mile-Long Leaky Pipe 70 Stories Underground?
Dan Lewis, author of the daily newsletter Now I Know (“Learn Something New Every Day, By Email”) joins us Wednesdays with surprising facts about the world of business.
When the pipes under your sink spring a leak, you call a plumber. But who does New York City call when the pipes carrying its drinking water from a reservoir two hours away start to leak?
That job calls for some something special: underwater repairmen.
Most of New York City’s water comes from the Catskills, more than 75 miles northwest of Manhattan. To get the water from the Catskills into the city's showers, sinks, and toilets, the government built huge tunnels—one is 13.5 feet wide, 1,200 feet below ground, and 45 miles (miles!) long. This particular tunnel, called the Rondout-West Branch Tunnel, started leaking in 2008.
The fact that the tunnel leaks is not that big of a deal in and of itself—leaks are rather common. What makes the Rondout-West leak notable is the sheer magnitude of the seepage: About 20 million gallons are lost on a typical day, and nearly double that on particularly bad ones. For approximately twenty years, the city’s Department of Environmental Protection had poo-pooed the problem, but with houses in the area of the leak (located 100 miles from Manhattan) complaining of flooding, the DEP changed its tune. The solution? The aforementioned repair crew.
As reported by the New York Times, the city hired six deep-sea divers, enlisting them for a month of repairs. During this month, the divers were confined to a pressurized, 24-foot-long tube (seen here), allowing them to enter the repair zone 70 stories underwater without having to go through depressurization each time to avoid compression sickness. The pressurized tank comes with basic amenities like showers and beds, but in general is a less-than-hospitable abode. Oh, and to make conditions survivable, the air mix is only 2.5 percent oxygen to 97.5 percent helium. This makes verbal communication difficult because the divers’ voices are constantly high-pitched.
The work entailed four-hour shifts performing repairs, removing potentially corroded piping, and the like, three divers at a time. Air, electricity, and oddly enough, water was funneled down to them at the job site. At the end of the shift, they spent another eight hours underwater resting before returning to the pressurized tank at the surface. Once “home,” other employees of the construction company provided them with food and clothes via an air lock. The food, however, tended to taste bland in the pressurized environment.
Unfortunately, the pipe is probably beyond repair. Instead, the DEP is building a bypass pipeline, which will break ground in 2013 and is scheduled to be completed in 2019—at the cost of roughly $2 billion.
Bonus Fact: There is a park in Austria which sits at the base of snow-capped mountains. During the winter, the park is relatively dry, with just a shallow pool contained within the landlocked area. But when the snow and ice melt in the warmer months, the park floods, submerged under a few feet of water, as seen here.
To subscribe to Dan’s daily email Now I Know, click here. You can also follow him on Twitter.