New York opens first segment of 3rd water tunnel 60-mile, $6 billion project will be done in about 20 years

August 21, 1998|By Fred Kaplan | Fred Kaplan,BOSTON GLOBE

NEW YORK - Deep beneath the Earth's surface - 60 stories deep - the workers in Shaft No. 19-B drill through some of the hardest bedrock that anyone has ever seen.

Around the clock, in three shifts of eight hours, they are building New York's City Water Tunnel No. 3, a $6 billion, 60-mile-long bit of urban infrastructure that officials say ranks as the largest construction project in the world.

The first segment of the tunnel, which spans 13 miles, was turned on to great fanfare recently, gushing forth water at a pressure of 350 pounds per square inch.

When finished, about 20 years from now, the tunnel will not only be the longest in the world, but will complete one of the world's most massive engineering marvels - yet, being entirely underground, perhaps also the least-noticed.

"I often ask New Yorkers if they know where their water comes from," said Joel A. Miele, commissioner of the Department of Environmental Protection, which runs the tunnel and all the city's water projects. "No more than 6 to 8 percent have the slightest idea."

The water for all three tunnels - Tunnels No. 1 and No. 2 were built in 1917 and 1936, respectively - comes from as far as 125 miles away, north of the city, coaxed out of the Croton, Delaware and Catskill reservoirs along the Hudson River.

Wending through an elaborate system of aqueducts, tunnels, and smaller reservoirs, the water streams into Yonkers, down through the Bronx, then off through various other tunnels and pipes into Manhattan, Queens, Brooklyn, and Staten Island.

Tunnels No. 1 and No. 2 carry, together, 1.5 billion gallons of water a day - 95 percent of it without any pumps, flowing along by simple force of gravity.

New York City consumes nearly every drop of this water. This led officials to start planning a third tunnel as far back as the mid-1950s. Not until 1970 did construction begin - and not until 2020 is it expected to end.

Shaft 19-B, plunging 672 feet below a far-flung industrial site in a decrepit area along the Brooklyn-Queens border, leads into a stretch of Tunnel No. 3's Second Stage, which is not due to come on line for seven years or so.

The elevator ride to the tunnel takes two minutes to hit bottom. (The ride back up is three minutes.) The elevator opens into a vast cavern dug out from the rock.

There's nothing remotely claustrophobic about the space, a cylinder 23 feet in diameter. A constant flow of air is pumped through a huge tube on the ceiling. Smaller pipes on the walls carry water. Railroad tracks have been laid on the floor, to bring the workers to the outer reaches of their drilling, now three miles away from the shaft. Conveyor belts stretch overhead, carrying the broken rocks back up to the surface.

Tunnel No. 3 has taken the lives of 23 workers in its 28 years of construction, but all but one of the deaths were caused by accidents typical of industrial projects - falls, electrocutions, collapsing equipment.

No one fears a cave-in of the tunnel itself. The rock that surrounds it was formed 450 million years ago, long before life began on this planet. It's as solid as anything. But just in case, 8-foot-long bolts have been hammered into the arc of the cylinder, the tunnel's ceiling, for extra stability.

Except for the life-support gear and the constant clanking of the pump and the chugging of the motor, the scene feels like another planet. The ground is muddy like clay. The walls are craggy, made of a rock that nobody has ever seen before.

The rough sections of the tunnel were created the old-fashioned way - by sandhogs, as the workers called themselves, wielding dynamite and hand drills.

In the newer area - built in just the past two years - the workers were given the Tunnel-Boring Machine, a 110-foot-long, worm-like device, spinning 50 huge cutters on a rotating head, that digs into the rock with 3.5 million pounds of thrust, capable of pushing forward at a rate of 15 feet per hour.

The cylinders that the machine have dug out are smooth and symmetrical. One finished section, which has been lined with concrete, glistens in the arc lights. The project's resident engineer, Ami Mukherjee, seemed jaded by the effect. "That's what concrete looks like when it's wet," he said. But, seen for the first time, it seems surreally spectacular, like a high-tech aircraft-hangar that somehow wound up on the moon.

Shaft 19B is twice as deep as any part of the city's first two water tunnels, but even it stops short of Tunnel No. 3's deepest point - an area under Roosevelt Island, just east of Manhattan, that goes 780 feet underground.

That segment of the tunnel is part of the 13-mile stretch that opened recently.

The Central Park fountain was first turned on in 1917, with the opening of Tunnel No. 1, but was immediately turned off and forgotten. City officials rediscovered it just six months ago, hooked its pipes up to Tunnel No. 3, and decided to turn it on again for symbolic effect. Now, the fountain is gushing all the time, as a publicly visible monument to the maze of metal and mud carved through the prehistoric rock down under.

Pub Date: 8/21/98

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