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Rhyme Reason
- N.Y. / Region | New York 101
Share - The city’s water is treated with chlorine, but the chemical can create harmful byproducts when mixed with organic compounds. In the 1990s, ultraviolet radiation was identified as a safe and effective supplementary treatment. But for it to be evenly applied, the water must be moving at constant speed.
- How New York Gets Its Water
Revelations about tainted water have sparked worry across the country. The New York Times decided to look at how the nation’s largest municipal water supplier delivers what has been called the champagne of drinking water to 9.5 million people.
By EMILY S. RUEB;
Illustrations by JOSH COCHRAN
- How New York Gets Its Water
Protecting Water at Its Source
The Catskill/Delaware watershed, which extends 125 miles northwest of the city, provides more than 90 percent of the city’s supply. The rest comes from the Croton watershed.
- Safeguarding the city’s water begins with protecting land that surrounds the streams, rivers, lakes and reservoirs.
The Catskill/Delaware watershed encompasses more than a million acres. The city, state and local governments and nonprofit land conservancies own 40 percent of the land.
The rest is privately owned, but development is regulated to prevent pollutants from getting into the water supply.
- The city has also upgraded septic systems and wastewater treatment plants in communities around the watershed and helped build municipal salt sheds and manure sheds on dairy farms to prevent harmful runoff.
“We’re treating things at the source, as opposed to at the end of the pipe,” said Paul V. Rush, deputy commissioner of the city’s Bureau of Water Supply.
As a result, the federal Environmental Protection Agency exempts water originating in the Catskill/Delaware watershed from its usual filtration requirements, a dispensation the agency gives to only a few other major cities.
- How New York Gets Its Water
An Engineering Marvel
The 92-mile-long Catskill Aqueduct, which plunges 1,100 feet underneath the Hudson River, was constructed a century ago.
- It can take 12 weeks to a year for water to wind its way to the city from the streams, tunnels, dams and reservoirs in the Catskills. All of it is delivered to the city by gravity alone.
“Gravity’s an important friend of ours,” said Mr. Rush, the deputy commissioner, explaining that it “works nonstop” and is “energy efficient.”
But the system is showing its age.
- The city plans to spend $3.4 billion over the next five years for hundreds of projects to fix decaying infrastructure.
Among the items on the to-do list is a new tunnel to bypass a portion of the Delaware Aqueduct that has been leaking more than 18 million gallons a day for decades. When it is shut down for repairs in 2022, the city will rely on the Catskill system, as well as Croton, where a $3.2 billion filtration plant was turned on last year.
- How New York Gets Its Water
Monitoring and Testing
The Catskill and Delaware Aqueducts feed into the Kensico Reservoir, where robotic buoys transmit information about water quality. Chlorine, which kills bacteria, and fluoride, for dental health, are added.
- Field scientists are constantly monitoring temperature, pH, nutrient and microbial levels.
Last year, robotic buoys recorded 1.9 million measurements, and field scientists collected 15,500 samples from reservoirs, streams and aqueducts upstate for analysis.
All of the data is fed into a centralized computer system, which also takes into account advanced weather forecasting to make determinations to predict the quality and quantity of water that day — and even six months into the future — at each reservoir.
- One issue of concern to water experts is turbidity, or cloudiness of the water. Heavy rain and high winds can sweep fine particles of clay and silt into the system that can inhibit treatment of the water.
Climate change is a major factor, too. Fluctuating precipitation patterns, forest health and water temperature can drastically affect the quality of the water and how much of it is available.
- How New York Gets Its Water
High-Tech Water Treatments
Over a billion gallons of water a day pass through an ultraviolet disinfection facility in Westchester County, the world’s largest.
The $1.54 billion plant uses a system of pipes to slow the water before it passes through one of 56 large containers that hold ultraviolet lights encased in quartz tubes that zap stomach-ravaging micro-organisms.http://www.nytimes.com/interactive/2016/03/24/nyregion/how-nyc-gets-its-water-new-york-101.html?_r=2&module=ArrowsNav&contentCollection=N.Y. / Region&action=keypress®ion=FixedLeft&pgtype=Multimedia
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