New York Third Water Tunnel
Choose another wonder
Location: New York, New York, USA
Completion Date: 2020
Cost: $6 billion
Length: 316,800 feet (60 miles)
Purpose: Water supply
Engineer(s): Grow, Perini & Skanska; Lehiavone & Shea
Six hundred feet below the busy streets of New York City, engineers are boring a 60-mile-long tunnel -- the largest tunnel in America. This tunnel wonít carry cars, trains, or even people, but it will deliver 1.3 billion gallons of water daily to nine million area residents. New York Cityís $6 billion Third Water Tunnel is one of the nationís largest and most complex public works projects ever attempted.
In 1954, New York City recognized the need for a new tunnel to meet the growing demand on its 150-year-old water supply system. Construction began in 1970 on the Third Water Tunnel, a tunnel designed to improve the dependability of New York Cityís entire water supply system. The majority of the tunnel is being carved with a 450-ton, 19-foot diameter rock-chewing device called a tunnel boring machine. Unlike the older water supply tunnels in New York City, water control valves in the Third Water Tunnel will be housed in large underground chambers, making them accessible for maintenance and repair.
When completed in 2020, the size and length of the Third Water Tunnel, its sophisticated valve chambers, and its depth of excavation will represent the latest in state-of-the-art tunnel technology.Here's how this tunnel stacks up against some of the longest tunnels in the world.
(total length, in feet)