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Groundwater System for 2007

New York City Groundwater Distribution Area

Between 1887 and 1996, the privately owned Jamaica Water Supply Company (JWS) operated a group of wells that served the communities of southeastern Queens and portions of Nassau County. In 1996, New York City purchased the Queens portion of the JWS and took responsibility for the delivery of drinking water to those communities served by the groundwater wells. After acquiring the JWS wells, the Department of Environmental Protection (DEP) renamed the group of wells "the Groundwater System."

Comprised of 69 wells, the Groundwater System provides drinking water to fewer than 100,000 people in New York City. Residents within the system receive groundwater or a mix of ground and surface waters depending on demand and supply availability. In 2007, New York City's Groundwater System (PWSID NY7011735) operated one well for two months of the year, which supplied a daily average of 1.1 million gallons of drinking water per day, less than 0.1% of the City's total usage.

Located in southeastern Queens, the Groundwater System covers an area of approximately 5.5 square miles. The neighborhoods connected to the Groundwater System include: Cambria Heights, Hollis, Holliswood, Jamaica, Kew Gardens, Queens Village, Richmond Hill, St. Albans, South Jamaica, and South Ozone Park.

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Wells in Operation in 2007

The table below lists the wells that were in operation in 2007:

Well* Town Aquifer Depth (ft.) Present Well Capacity (mgd)
5 Hollis Magothy or Cretaceous Formation 275 1.73

* - Wells are each assigned a number for easy reference. These numbers may be followed by the letters A, B, C, or D. These letters indicated multiple wells housed at the same location. For example W6, W6A, W6B, W6C, and W6D are all distinct wells at the same address.

Well 5 was the only well in operation in 2007, running briefly into distribution in January and February of 2007. For a more extensive listing of all the Groundwater System wells, accompanied by detailed location, aquifer, depth and operational information, see:

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An aquifer is a natural underground layer of porous, water-bearing materials (sand, gravel) usually capable of yielding a large supply of water. Three aquifers run the length of Long Island, which includes Brooklyn and Queens Counties: the Upper Glacial, which is the shallowest; the Magothy, which is the middle layer; and the Lloyd, which is the deepest. Formed approximately 60 million years ago, the three aquifers are separated by layers of clay.

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Treatment Information

All groundwater entering New York City's distribution system is treated with chlorine, fluoride, food grade phosphoric acid, and, in some cases, sodium hydroxide. New York City uses chlorine to meet the New York State Sanitary Code and federal Safe Drinking Water Act disinfection requirements. Fluoride, at a concentration of one part per million, is added to help prevent tooth decay and has been added since 1966 in accordance with the New York City Health Code. Phosphoric acid is added to create a protective film on pipes that reduces the release of metals such as lead and copper from household plumbing. Additionally, a sequestering phosphate is applied at several wells to prevent the precipitation of naturally occurring minerals, mostly iron and manganese, in the distribution mains and customers' household piping. Air stripper facilities can be operated at several wells to remove volatile organic compounds (VOCs). The only well in operation in 2007 had an air stripper in operation.

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Operational Information - 2007

Well 5 of the Groundwater System was the only well online for a brief portion of the year in January and February of 2007. Well 5 was operated remotely via telemetering from Station 6, which is the headquarters for Groundwater Operations, located in Jamaica, Queens. This well was started and stopped on a daily basis depending upon distribution demands. In general, the well was started everyday between 5AM and 6 AM (as people start to wake up) and shut down when the system demand was met. Well 5 was then restarted around 3 PM as system demand increased and shutdown again later in the evening, when system demand decreased.

The other 68 wells which comprise the Groundwater System were not used for drinking water distribution in 2007. These wells are either mechanically inactive, for emergency use only, or have poor water quality. This information is available on the Service Status Table.

Individual Well Information:

Well 5: Originally put into service in 1924, Well 5 was designed at a flow rate of 1200 gallons per minute (gpm). Water is pumped from the wellhead, or water source, through a water treatment plant in order to remove any VOCs from the water before it is discharged into the distribution system. Well 5 was removed from service in February 2007 due to a pump failure. The pump has since been replaced, but the station is undergoing other repairs and improvements before it is put back into service.

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Water Quality Data

Index Numbers

DEP assigns index numbers to sampling locations throughout the distribution system. The nomenclature of the index for a well sample location signifies the status of the water at a specific tap. An index number followed by the letters E, F or T denotes sampling sites that are treated, or finished groundwater. Well index numbers that have no letter after the number, or are followed only by the letters A, B, C, D, I or S are considered untreated, or raw water. Examples of untreated water IDs are W5 and W23A. Examples of treated water are W5E and W23AT. The following table illustrates this in greater detail:

Index Numbers Description
W##, W##A-D, I, S Groundwater wells sampling points prior to final treatment
W##E Effluent finished groundwater from wells with air-stripping
W##F Finished groundwater effluent from wells without any special treatment
W##T Treated finished groundwater effluent from sequestering/iron treatment wells

Data Tables and Graphs

The tables listed below contain water quality data from 2007. The only well in operation for the year was Well 5, which was online for a brief period in January and February of 2007. Additional water quality parameters, not analyzed in 2007, were measured in 2006. Please see the 2006 tables for additional data.

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GAC – granular activated carbon, a form of particulate carbon manufactured with increased surface area per unit mass to enhance the adsorption of soluble contaminants.

gpm – gallons per minute.

mgd – million gallons per day.

MTBE - Methyl Tertiary-Butyl Ether, formerly an additive to gasoline.

VOCs – volatile organic compounds, a class of organic compounds that includes volatile liquids.

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Previous Years

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Reservoir Levels

Current: %

Normal: %