Quick, how do you repair the 65 years' worth of decay in the longest tunnel in the world while keeping the billion gallons of water per day it delivers to 9 million thirsty New Yorkers flowing?
Answer: With a fancy computer program and a giant plug.
Today, the Department of Environmental Protection announced the next phase in a public works project that makes digging a tunnel under the city of Boston look easy: updating the Delaware Aqueduct, which has transported the water from four reservoirs in upstate New York to taps in New York City without any significant repairs since 1944.
The 85-mile-long tunnel has become notoriously leaky in recent years, and this fall, the DEP will close off an entire section of it for three weeks in order to install a plug that will keep workers installing repair equipment dry and alive. From the DEP's press release:
The shutdown will allow workers to perform work on a shaft necessary to ultimately repair the Aqueduct. Earlier this year, divers investigated the area around an existing hatch in the shaft that leads to the Aqueduct. In the fall, this area will be reinforced, which will lay the groundwork for the next phase of work, the installation of a pumping station in the shaft.
To prepare for tunnel closure in October, the DEP will release water from the reservoirs this summer using its half-built $5.2 million water-management computer system. The idea is to keep the trout streams and sink faucets flowing as much as possible.
The repair project is no joke. Watchdog groups like the Riverkeeper have warned that if the DEP isn't careful, it could cause a catastrophic tunnel collapse:
[D]raining the aqueduct could lead to a tunnel collapse, as the internal pressure of the water decreases relative to the pressure exerted by the rock on the outside of the tunnel.
To read the DEP's full press release, click here. Photo of the Delaware Aqueduct under construction from NYC DEP.
