THE NEW YORK City watershed, formed in 1842 to serve the growing needs of the city, today also provides water for a million residents of Ulster, Orange, Putnam and Westchester counties. Altogether, 9 million people in the New York metropolitan area consume about 1.2 billion gallons of water daily, Michaels said.

There's a long and bitter history between New York City and its upstate watershed communities over land rights and the regulation of homes and businesses near the city's 19 upstate reservoirs and three controlled lakes, which cover nearly 2,000 square miles in the Catskill Mountains and points east of the Hudson River.

Though most city residents enjoy clean, fresh water with the turn of a tap, few know about the struggle it has taken for that water to reach them, the legal battles over land rights and the homes and businesses that were sacrificed to build their water system.

Sandhogs, the workers who labor on the tunnel, also bear a sad history. Since 1970, when construction on Tunnel No. 3 began, 24 workers have died in construction-related accidents.

UPSTATE, 2,000 residents of the area now covered by the Ashokan Reservoir were forced to move in the early part of the 20th century when their land was seized through eminent domain. Ten thousand acres were cleared, and more than 500 homes, 10 schools and six railroad stations were either moved by their owners or burned by the city. Most residents didn't put up a fight.

"I think they were kind of in shock," said Ruth Ann Muller, the town of Olive historian, who wrote a thesis on the uprooting of thousands of gravesites.

The New York Times derisively dubbed the area "aboriginal Ulster" as the city looked to the rural county to meet its water needs.

The tension between upstate and downstate has changed some, Muller says, but many of the old-timers still carry a grudge. Today, septic systems, municipal wastewater treatment and local economic development are all closely monitored to ensure water sources remain clean and safe.

As in 1917, when Tunnel No. 1 was activated, the cleanliness of the city's water depends on strict land-use regulation. At the Ashokan Reservoir, the only physical filter the city's drinking water passes through is a large metal net resembling a chain link fence.

UNDERGROUND at Tunnel No. 3, some 250 sandhogs and 70 to 80 operating engineers are on the payroll for the massive project, which uses a tunnel-boring machine to cut up to 92 feet per day through the bedrock beneath Manhattan.

"It's a man's world," says a Department of Environmental Protection employee, who gives a safety lesson required for all non-employees who enter the tunnel.

The tunnel-boring machine, or TBM, was purchased second-hand for $8 million and flown to the United States from Norway, said Louis Huang, chief of waterworks construction for the Department of Environmental Protection.

The boring mechanism alone weighs 200 tons; the machine was disassembled and taken down an elevator in pieces and reassembled before work could begin, Huang said. That process alone took several months.

THE TUNNEL-BORING machine works by applying approximately 700,000 pound of pressure from each of its 27, 300-pound cutters, which continuously rotate and chip away at the bedrock. The rotating head cuts into the rock face, and pieces that chip off are removed by a conveyor belt, which carries about 3 million pounds of muck each day.

Previously, excavating was accomplished through a "drill and blast" method, which was more primitive and labor-intensive. Workers would drill a hole into bedrock, then detonate an explosive placed inside the drilled pocket, Huang said.

HUANG, who says he enjoys his work, looks forward to the day when the tunnel will be completed. "It will be a big accomplishment," he said.

When boring is completed, the tunnel will be lined with concrete, Huang said. The finished tunnel will be 10 feet in diameter.

Sandhogs work around the clock seven days a week, with shifts from 7 a.m. to 3 p.m., 3 to 11 p.m. and 11 p.m. to 7 a.m. But the intense, production-motivated schedule is not without rewards: sandhogs can make up to $100,000 per year.

THE ONLY female operating engineer on staff is Lori Kirk, a mother of four and the project's elevator operator. The elevator is a noisy metal cage that takes about four minutes to descend the 500 feet to the construction site.

Kirk, who holds a bachelor's degree in English from Villanova University, said she joined Local 14 after college, and the flexibility the job provides allows her to care for her children.

"They treat me wonderful," Kirk said of the men who work underground, many of whom have families of their own. Kirk estimates she operates the lift 30 to 50 times a day.

THE NICKNAME "sandhogs" originally was given to workers who removed soft earth during the construction of the Brooklyn Bridge in the 1870s.

The title still conveys a skill uncommon among laborers and a sense of pride among those who labor in an 8.5-mile stretch between lower Manhattan and Central Park, 540 feet below street level.

CLYDE Beatty of Middletown said he began to work on the tunnel in 1972, when he was 22.

"I was the cool kid who didn't put in ear plugs," Beatty recalled, saying he woke up "stone deaf" the next morning. Thankfully, it turned out to be a temporary condition.

"All my lessons have been learned the hard way," Beatty said.

The risks of working in the tunnel are constant, but years can lessen a worker's sensitivity to the environment.

"You can become lackadaisical, and lose respect for your surroundings," Beatty said.

AMAZINGLY, despite the years of clamor underground, "no one knows that this is down here," said Ted Dowey, the tunnel project's executive construction manager.

Only one case of noise from the tunnel was ever detected, Dowey said, when a recording studio in Queens complained.

IRWIN Sylvester, a sandhog for more than 20 years, said the men he works with have become like a family to him.

Steve Large, another sandhog, agrees that the close-knit group provides a good system of support, but no replacement for the real thing.

Large looks forward to going home to his wife at the end of the day but said working in the tunnel has become commonplace to him.

"To me, it seems like working in someone's basement," he said.