Croton.
In New York, the word is synonymous with water — Croton River, Croton Falls, Croton Aqueduct, Croton Reservoir.
But no one in the city has drunk a drop of Croton water since 2008.
New York long prided itself on having the largest unfiltered water system in the country, drawing on the Croton Watershed in Westchester and Putnam Counties, and the more distant, rural Catskill and Delaware Watersheds in upstate New York. In 1993, the federal government required the city to filter Croton water, coming as it did from an area that had been intensively developed.
Croton water had accounted for about 10 percent of the 1.1 billion gallons consumed daily in New York City. It was shut off six years ago, its place temporarily taken by water from the Catskill and Delaware systems.
Much attention has focused since then on the problems faced by the city Department of Environmental Protection in constructing a $3.2 billion filtration plant under Van Cortlandt Park in the Bronx. The budget has ballooned. The timeline has stretched. Contractors have been suspected of and have admitted to fraud. And this litany takes no account of the neighbors’ many objections.
That is why the sight of a 100-year-old, 13-foot-tall, 20,000-pound manganese bronze guard valve, laid out flat on the ground near the Jerome Park Reservoir in the Bronx, was welcomed this week by James J. Roberts as a quiet milestone.
At a cost of $1 million, this valve and its twin are being replaced with 6,700-pound stainless steel valves, newly fabricated by an Italian company called Vanessa in Lugagnano Val d’Arda, roughly midway between Milan and Bologna.
Installation of the new valves will allow the final links to be completed in a network of pipes through which as many as 290 million gallons of filtered Croton water are to begin flowing daily to Manhattan and the Bronx, said Mr. Roberts, the deputy commissioner for water and sewer operations at the city’s environmental agency. The filtration plant is to be finished next year.
The changing of the valves offers a chance to appreciate the foresight with which the water system was developed and the magnitude of its scale. One rarely has the chance to walk around a bronze fixture the size of a subcompact car.
“I have a fondness for these,” Mr. Roberts said of the old valves, “because they’re really a bridge between our history, our legacy and our future.”
One thing that has not changed much in recent years is gravity. Water is generally propelled through New York’s system by gravity, since it comes from reservoirs that are at a much higher elevation than the city itself.
The challenge facing engineers like Mr. Roberts is not so much pumping water. It pretty much rises on its own, as high as the sixth floor in some parts of town.
Instead, the stress on the system comes from resisting and channeling all that pressure. Mr. Roberts estimated that a force of about 180,000 pounds was typically exerted on the City Water Tunnel No. 1 guard valves.
There are typically three key types of valves between the enormous, gravity-fed water tunnels hundreds of feet below ground and the faucet in my kitchen sink that needs to be fixed again soon. (Note to self.)
The riser valve comes first. It is placed where the vertical shaft from the tunnel meets a six-foot-diameter riser pipe that will carry the water farther up. This valve, shaped roughly like an inverted cone, can be raised or lowered to regulate flow.
Capping the top of the riser pipe is a hollow bronze sphere, anchored into bedrock. The guard valve is bolted onto this cap to regulate the flow from the riser into the distribution system, where it is further controlled by operating valves.
The old guard valves worked by the mechanical raising and lowering of a four-foot-wide disc of solid bronze. By contrast, the new valves have gates that pivot on a vertical axis. This will make them easier to open and close, Mr. Roberts said.
That was not the only factor influencing the change, he said. Where the 1914 valves were custom-made, the Vanessa valves are virtually off-the-shelf. That means a much shorter delivery time and much lower cost, without sacrificing performance. Replicating the manganese bronze valve might cost $1 million and take years.
Mr. Roberts said the new valves might last more than 40 to 50 years. That is a longer-than-usual horizon for a city agency, but Mr. Roberts said, “My colleagues and I see ourselves as stewards of the system.”
As such, they know better than to discard functioning antique fixtures. The valves will be warehoused instead.
“This valve’s pedigree and the shape it’s in after a century of performance speaks for itself,” Mr. Roberts said. “If we needed it in an emergency, I’d be comfortable installing it.”
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