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New York City water supply system

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What's So Great About New York City Water? | 6sqft

 New York City's water supply system is one of the most extensive municipal water systems in the world. This complex system relies on a combination of aqueducts, reservoirs, and tunnels to meet the daily needs of New York City's more than eight million residents and its many visitors.


Thanks to well-protected wilderness watersheds, New York's water treatment process is simpler than in other American cities. One advantage of the system is that 95% of the total water supply is supplied by gravity. The other 5% needs to be pumped to maintain pressure, but this is sometimes increased in times of drought when the reservoirs are at lower than normal levels.

The city has sought to restrict development throughout its watershed. One of its largest watershed protection programs is the Land Acquisition Program, under which the New York City Department of Environmental Protection (DEP) has purchased or protected, through conservation easement, over 130,000 acres (53,000 ha) since 1997.

Responsibility for water supply, sewerage and wastewater treatment

Responsibility for the city water supply is shared among three institutions: the New York City Department of Environmental Protection ("DEP"), which operates and maintains the system and is responsible for investment planning; the New York City Municipal Water Finance Authority ("NYW"), which raises debt financing in the market to underwrite the system's costs; and the Water Board, which sets rates and collects user payments.

New York City Department of Environmental Protection

The DEP has a workforce of over 6,000 employees. It includes three bureaus in charge of, respectively, the upstate water supply system, New York City's water and sewer operations, and wastewater treatment:

  • The Bureau of Water Supply manages, operates and protects New York City's upstate water supply system to ensure the delivery of a sufficient quantity of high quality drinking water. The Bureau is also responsible for the overall management and implementation of the provisions of the city's $1.5 billion Watershed Protection Program.
  • In addition to operating and maintaining the water supply and sewerage system, the Bureau of Water and Sewer Operations is also responsible for the operation of the Staten Island Bluebelt, an ecologically sound, cost-effective natural alternative to storm sewers, which occupies approximately 15 square miles (39 km2) of land in the South Richmond area of Staten Island. This project preserves streams, ponds and other wetland ("bluebelt") areas, allowing them to perform their natural function of conveying, storing and filtering storm water.
  • The Bureau of Wastewater Treatment operates 14 water pollution control plants treating an average of 1.5 billion US gallons (5,700,000 m3) of wastewater a day; 95 wastewater pump stations; eight dewatering facilities; 490 sewer regulators; and 7,000 miles (11,000 km) of intercepting sewers.
  • New York City Municipal Water Finance Authority

    The NYW finances the capital needs of the water and sewer system of the city through the issuance of bonds, commercial paper, and other debt instruments. It is a public-benefit corporation created in 1985 pursuant to the New York City Municipal Water Finance Authority Act. The Authority is administered by a seven-member Board of Directors. Four of the members are ex officio members: the Commissioner of Environmental Protection of the City, the Director of Management and Budget of the City, the Commissioner of Finance of the City, and the Commissioner of Environmental Conservation of the State. The remaining three members are public appointments: two by the Mayor, and one by the Governor.

    New York City Water Board

    The New York City Water Board sets water and sewer rates for New York City sufficient to pay the costs of operating and financing the system, and collects user payments from customers for services provided by the water and wastewater utility systems of the City of New York. The five Board members are appointed to two-year terms by the Mayor.

    Overview of infrastructure

    New York City's water system consists of aqueducts, distribution pipes, reservoirs, and water tunnels that channel drinking water to residents and visitors. A comprehensive raised-relief map of the system is on display at the Queens Museum of Art.

    Reservoirs and aqueducts

    The water system has a storage capacity of 550 billion US gallons (2.1×109 m3) and provides over 1.2 billion US gallons (4,500,000 m3) per day of drinking water to more than eight million city residents, another one million users in four upstate counties bordering on the water supply system, and visitors to the region. Three separate sub-systems, each consisting of aqueducts and reservoirs, bring water from Upstate New York to the New York City:

  • The New Croton Aqueduct, completed in 1890, brings water from the New Croton Reservoir in Westchester and Putnam counties.
  • The Catskill Aqueduct, completed in 1916, is significantly larger than New Croton and brings water from two reservoirs in the eastern Catskill Mountains.
  • The Delaware Aqueduct, completed in 1945, taps tributaries of the Delaware River in the western Catskill Mountains and provides approximately half of New York City's water supply.
  • The latter two aqueducts provide 90% of New York City's drinking water. Water from both aqueducts is stored first in the large Kensico Reservoir and subsequently in the much smaller Hillview Reservoir closer to the city.

    Brooklyn Reservoirs

    Brooklyn has had many water reservoirs; they can be seen on an 1864 map of Brooklyn Waterworks. They are listed below, from east to west:

    1. Hempstead Reservoir
    2. Smith's Pond
    3. Rockville Reservoir
    4. Valley Stream Pond
    5. Watts Pond
    6. Clear Stream Reservoir
    7. Brookfield Reservoir
    8. Conselyea Pond
    9. P. Cornells Pond
    10. Springfield Pond
    11. One Mile Pond
    12. Jamaica Reservoir
    13. Ridgewood Reservoir
    14. Mount Prospect Reservoir

    Tunnels and distribution system

    From the Hillview Reservoir water flows by gravity through three tunnels under New York City, where water rises again to the surface under natural pressure, through a number of shafts. The three tunnels are:

    1. New York City Water Tunnel No.1, completed in 1917. It runs from the Hillview Reservoir under the central Bronx, Harlem River, West Side, Midtown, and Lower East Side of Manhattan, and under the East River to Brooklyn where it connects to Tunnel 2. It is expected to undergo extensive repairs upon completion of Tunnel No. 3, in 2020.
    2. New York City Water Tunnel No. 2, completed in 1935. It runs from the Hillview Reservoir under the central Bronx, East River, and western Queens to Brooklyn, where it connects to Tunnel 1 and the Richmond Tunnel to Staten Island. When completed, it was the longest large diameter water tunnel in the world.
    3. The uncompleted New York City Water Tunnel No. 3, the largest capital construction project in New York City's history (see below).

    The distribution system is made up of an extensive grid of water mains stretching approximately 6,500 miles (10,500 km).

    The Croton Water Filtration Plant Project

    In order to comply with federal and state laws regarding the filtration and disinfection of drinking water, the U.S. Environmental Protection Agency (EPA) and the New York State Department of Health called on the city to create a treatment plan to serve the Croton System. The underground filtration plant is under construction in Van Cortlandt Park. While the Bloomberg administration originally budgeted the project at $992 million in 2003, an audit by the city's comptroller placed the actual costs at $2.1 billion in August 2009.

    Delaware Aqueduct repair

    The New York City water supply system leaks at a rate of up to 36 million US gallons (140,000 m3) per day. A complex five-year project with an estimated $240 million construction cost was initiated in November 2008, to correct some of this leakage.

    Water tunnel No. 3

    The construction of Water tunnel No. 3 is intended to provide the city with a critical third connection to its Upstate New York water supply system, allowing the city to close tunnels No. 1 and No. 2 for repair for the first time of their history. The tunnel will eventually be more than 60 miles (97 km) long. Construction on the tunnel began in 1970, and its first and second phases are completed. The latter opened with a ceremony under Central Park, in 2013. Completion of all phases is not expected until at least 2020.


    New York City water supply system Wikipedia

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