New York Thirsts for Third Water Tunnel
But at 1.5 billion gallons a day, city water consumption already exceeds the long-term capacity of the supply system. URBAN PIPELINE
MORE than 350 feet below the city's streets, nine big and grimy sandhogs straddle a metal deck and guide a six-ton concrete form as it is lowered by an American 9260 crane. Working in misty darkness spotlighted by arc lamps, the team spends its eight-hour shift lining about 10 feet of a 20-foot diameter shaft with pressurized concrete. The shaft plummets into the cavernous depths of the city's partially completed third water tunnel. The painstaking and dangerous procedure typifies work in ``the hole,'' as workers call the tunnel, which has been under construction since 1970.Skip to next paragraph
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The third tunnel is designed to handle most of New York's water needs. Its network of huge pipes will be able to deliver 1.2 billion gallons of water per day to points throughout the city. Officials believe it will not be completed until well into the next century.
By the time the last valve is in place, the tunnel's price tag is expected to total $5 billion - the most expensive project financed by the city. In 18 years of blasting through the Fordham gneiss bedrock, 23 workers have been killed.
Despite the cost in lives and dollars, the third tunnel will not bring more water to slake the city's lusty thirst. New Yorkers consume about 200 gallons of water per person each day, according to Tina Casey, a spokeswoman for the city's Department of Environmental Protection, which oversees the Bureau of Water Supply.
The tunnel will carry water from a holding reservoir in Yonkers, rather than from new sources, but officials promise better delivery and pressure throughout the city.
``Every city has its own unique set of water problems,'' said the assistant resident engineer for the project, Ted Dowey, as he stood at the bottom of the third tunnel's west shaft. ``New York's biggest problem is in bringing water to the city from reservoirs that are 125 miles away.''
More troubling is the city's inability to monitor the condition of the two aging, mammoth tunnels that distribute all its water. Tunnel No. 1, built in 1917, and tunnel No. 2, opened in 1937, deliver close to 2 billion gallons of water during the city's hottest summer days - about 60 percent more than they were designed to handle, according to Jack Ledger, resident engineer for construction of tunnel No. 3.
Because the two tunnels are filled with water and cannot be emptied, they have never been inspected. To inspect one would require shutting it down - something the city cannot afford. A shutdown of one of the tunnels, or a cave-in, would leave much of the city without water.
Officials say that a crippling accident in one of the tunnels is unlikely. Yet they acknowledge that stress, age, and no opportunity for maintenance may be exacting a heavy price in water losses. The city states that perhaps 10 percent of its water is lost to leaks in the delivery system, a figure that State Assembly Environmental Conservation Committee chairman Maurice Hinchey calls a ``gross underestimate.'' Noting that many parts of the aging system date from before the turn of the century, Mr. Hinchey estimates that the city may be losing 30 to 40 percent in leaks.
Sometime around the turn of the 21st century, construction will be far enough along to enable the third tunnel to deliver water to much of the city. Engineers will then be able to close one of the other tunnels to make inspections and repairs.