New Yorkers will proudly tell you that the city has some of the finest tap water that you can find. But for nearly a century, all of Manhattan has been served by a single water tunnel that hasn’t been shut down for maintenance since it first opened in 1917. That’s no longer the case. The city has finally completed work on a water tunnel designed to provide some redundancy to Manhattan’s lifeline.

The tunnel runs 500 feet below the surface and is 12 feet in diameter. The section activated this week runs for 8.5 miles, serving all of Manhattan below Central Park. Ten separate shafts, each about a mile apart, use pressure alone to bring the water up to local distribution systems closer to the surface. Meanwhile, an earlier stage of the water tunnel completed in 1993 brings water 13 miles down from Yonkers, which lies just north of the city limits. In all a total of 82 million cubic feet of soil and rock has been removed from under the city — enough to fill Madison Square Garden 200 times. An astounding 30 million cubic feet of concrete has been poured to line the tunnels. A total of 24 "sandhogs," the term given to the men behind many of the city's legendary urban mining projects, have died to complete work on the latest tunnel.



Construction on this massive project to build Water Tunnel 3 (Tunnel 2 serves outer boroughs Queens and Brooklyn) has been underway, in fits and starts, since 1970. A total of $4.7 billion has been spent to bring a second water tunnel to Manhattan, with $2.7 billion of that funding coming under Mayor Bloomberg’s administration since 2003. That makes it one of the city’s largest public works projects ever.

But perhaps what’s most impressive is the system as a whole. The water that serves all of New York City comes from a number of reservoirs upstate. Aqueducts, some of which were built in the late 19th century, continue to provide water for the city. Water Tunnel 1, completed in 1917, was built with enough capacity that it remains completely sufficient today — the third tunnel was built for redundancy, not increased volume.

To announce the news, Mayor Bloomberg triumphantly gave a press conference from a massive valve chamber some 200 feet below Central Park. The soaring space has the presence of a cathedral — a place of worship for public works, if you will. Speaking of the water tunnel, he said "When I came to office, I asked what could literally close down the city. And the water tunnel could have really done that. I said, we have just got to make the investments." He added, "It's not sexy. And nobody says thank you." The third and final leg of Water Tunnel 3 remains to be completed. It’s set to provide redundancy in Brooklyn in Queens, which are both served by a single tunnel completed in 1936. The 10.5-mile long tube is expected to be completed in 2021.

Lead image credit: REUTERS/Mike Segar

Grid View Mayor Michael Bloomberg triumphantly announced the completion of the second stage of Water Tunnel 3 from a valve chamber 200 feet below Central Park. The project to provide redundancy to Manhattan's water system has been underway since 1970. (Photo credit: NYC Department of Environmental Protection)

Water Tunnel 3 was proposed in 1954 in order to provide backup for the aging Water Tunnel 1, which was completed in 1917. Work began in 1970 on stage one, pictured above in 1978 before concrete was laid. Workers used the "drill and blast" technique to make it through 13 miles of bedrock. (Photo credit: NYC Department of Environmental Protection)

Stage 1 has a diameter 20 to 24 feet — significantly larger than the city's other water tunnels — to accomadate increased capacity. This completed section from 1978 brings water down from a reservoir just north of the city down to Central Park. (Photo credit: NYC Department of Environmental Protection)

This 1978 photo shows a passageway in water tunnel 3 leads to the surface. The diameter of the tunnel decreases and water pressure forces liquid to the surface, 500 feet up. (Photo credit: NYC Department of Environmental Protection)

By 1994, workers started using massive tunnel boring machines to work their way through the bedrock. This photo, from April 21st, 1994, shows the first day the machine was used. (Photo credit: NYC Department of Environmental Protection)

The boring machine creates a smoother tunnel through the ground than the drill and blast technique, meaning less concrete is necessary to create a cylindrical tube, as seen in this 2006 photo of construction in tunnel 3. (Photo credit: NYC Department of Environmental Protection)

Section two of Water Tunnel 3, which was activated this week, runs for 8.5 miles from Central Park down to the rest of Manhattan. (Photo credit: NYC Department of Environmental Protection)

Construction on the tunnels for stage two were completed in 2008, and final preparations — including the construction of riser shafts to bring water to the surface — were finished this year. (Photo credit: NYC Department of Environmental Protection)

This section of Water Tunnel 3 has been lined with a steel structure to support the concrete that will carry the water. (Photo credit: NYC Department of Environmental Protection)

Water Tunnel 3 is one of the largest public works projects in New York City history, but the water system itself is far larger than one tunnel. In the mid 1800s the city decided to import water from reservoirs to the north. Workers here are constructing the second aqueduct to serve the city, which was completed in 1890. It remains in use today. (Photo credit: NYC Department of Environmental Protection)

Work on Water Tunnel 1, designed to serve Manhattan, was completed in 1917. Workers here in 1914 use the drill and blast method 500 feet below the surface to dig through the bedrock. (Photo credit: NYC Department of Environmental Protection)

Water Tunnel 1 was built with incredible capacity. To this day it remains sufficient to serve all of Manhattan. The new tunnel is designed merely to allow for extensive repairs to the older system, which hasn't been taken offline in nearly 100 years. In this photo, construction crews fill the gap between the concrete tunnel and the bedrock with grout. (Photo credit: NYC Department of Environmental Protection)

Significant sections of the Bronx, Queens, Brooklyn, and Staten Island are served by Water Tunnel 2, which was put into service in 1936. Above, crews work in 1931 on a Brooklyn section of the tunnel that's 17 feet in diameter. (Photo credit: NYC Department of Environmental Protection)

This map diagrams the entire system that brings water from the land and mountains north of the city. Several reservoirs — some of which are over 100 miles from the city — hold water that moves south solely with gravity. (Photo credit: NYC Department of Environmental Protection)

The Cannonsville reservoir, located near the New York–Pennsylvania border some 100-plus miles from the city. Completed in 1964, it's the newest of the reservoirs. It holds nearly 100 billion gallons of water and was created by damming the Delaware river and destroying the town of Cannonsville, which sat in the valley. (Photo credit: NYC Department of Environmental Protection)



