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- Background
Encompassing almost 2,000 square miles, the New York City Water Supply System consists of the Croton, Catskill, and Delaware Watersheds. Within these three watersheds, rain and snow are captured and stored in 19 reservoirs and three controlled lakes, with a capacity to hold approximately 580 billion gallons of fresh water.
About one billion gallons of water is delivered each day to more than 8.6 million people by gravity.
From washing your hands to your daily shower and flushing the toilet, like most of the developed world, many New Yorkers really don’t give much thought about where their water originates from, and pretty much take it for granted. But delve a little deeper, and there’s actually a fascinating journey that the water you use on a daily basis takes to reach your home.
Beginning up to 125 miles away in upstate New York, the water travels through mountains and deep valleys, and then once it’s in the city it flows through underground tunnels and into distribution chambers. Along the way, the water is disinfected by ultraviolet light, treated with chlorine, fluoridated and tested for purity before it’s delivered into buildings, with gravity alone being sufficient enough to push it at least six stories high!
New York City is a water-scarce city. Despite being surrounded on all sides by waterways and located in one of the rainier regions of America, the landscape upon which it was built lacks a significant supply of fresh water.
All the Watersheds of NY State
2. Concerns to Protect Watersheds
As water travels over the land or through the ground, it picks up naturally-occurring minerals as well as contaminants from animals and human activities. Thus, pollution sources are classified as point or nonpoint. A point source originates from a single location, such as a sewage treatment plant which may discharge clean, treated wastewater from a pipe into a river or stream. Nonpoint sources are diffuse—they don’t have a single point of origin and are generally carried off the land along with surface water during rain events.
Watershed protection efforts generally focus on human and animal contaminants, and they are tailored to address both the type of pollution source—point or nonpoint—as well as the way pollutants are transported across the landscape. Many scientific studies show there is a direct connection between the activities that occur within a watershed and diminished water quality. This happens when few or no management practices exist and contaminants are simply washed off the landscape or released directly into streams that flow into a water supply.
The essence of watershed management—which is the process of organizing and guiding land and natural resource use to reflect the competing needs and priorities of all stakeholders—is to prevent contaminants from reaching water resources. With careful planning and communication, water quality can be protected while still serving multiple priorities.
In the New York City water supply watersheds, key stakeholders include the nine million urban consumers of the water supply, nearly a quarter-million residents of the older and more suburbanized Croton Watershed (East of Hudson), tens of thousands of residents of the rural Catskill/Delaware Watershed (West of Hudson), and the diverse flora and fauna of the entire watershed ecosystem. This complex web of multiple stakeholders means that watershed protection requires a delicate balance between urban/rural and upstate/downstate interests.
To maintain the quality of the water, testing is done at 1,000 sampling stations around the city. Remember – NYC is only one of five big municipalities that’s allowed by the federal government to supply unfiltered water.
Major Watersheds for NYC
Major Watersheds for NYC
The Croton System
Located in Westchester, Putnam, and Dutchess Counties, the Croton system has 12 reservoirs and three controlled lakes. The largest, the New Croton Reservoir, can hold 19 billion gallons of water. The system normally supplies 10 percent of the City's drinking water, but can supply more when there is a drought in the watersheds farther upstate.
The Catskill System
The Catskill system includes two reservoirs and supplies up to 40 percent of the City's daily needs. The Catskill watershed is located in parts of Greene, Ulster, and Schoharie Counties, about 100 miles north of New York City and 35 miles west of the Hudson River.
The Delaware System
The Delaware system, in parts of Delaware, Ulster, and Sullivan Counties southwest of the Catskill watershed, includes four reservoirs which provide 50 percent of the City's daily water needs. The largest is the Pepacton, which can hold over 140 billion gallons of water — more than the entire capacity of the Croton system.
3. Miles & miles of aqueducts
3. Miles & miles of aqueducts
The water flows from the reservoirs and lakes through an impressive system of aqueducts and tunnels, including the 100 year old Catskill Aqueduct – this extends 92 miles from the Ashokan Reservoir in the Catskill Mountains. It relies on gravity alone to carry the water, and when it was completed in 1916, the Aqueduct was considered to be an engineering masterpiece on the same level as the Panama or Suez canals.
The Catskill Aqueduct has an operational capacity of approximately 550 million gallons per day. It usually operates well below capacity with daily averages around 350-400 million gallons of water each day. About 40% of New York City’s water supply flows through the Catskill Aqueduct. Constructed between 1939 and 1945, the Delaware Aqueduct carries approximately half of the New York City water supply of 1.3 billion gallons per day. A $1 billion project to repair the 36 million gallons per day leak is currently underway.
Fact: Stretching 85 miles, the Delaware is so large that a two man submarine has been used to inspect it for leaks.
Into the tunnels…
Into the tunnels…
From the aqueducts, the water is then distributed throughout the city via three tunnels and routed to distribution mains.
Water Tunnel No.1 – Completed in 1917, this tunnel was built with incredible capacity, and to this day it remains sufficient enough to serve all of Manhattan. It runs from the Hillview Reservoir to Brooklyn where it connects to Tunnel No.2. Tunnel No.1 is expected to go under extensive repairs upon completion of Tunnel No.3 in 2020.
Water Tunnel No.2 – Completed in 1936, this tunnel runs from 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, Tunnel 2 was the longest large diameter water tunnel in the world.
Water Tunnel No.3 – Under construction since 1970, Tunnel 3 is the largest capital construction project in New York City history. It’s being constructed by the New York City Department of Environmental Protection to provide the city with a third connection to its upstate water supply. Costing over $6 billion, the tunnel will be more than 60 miles long and will travel 500 feet below street level in some sections. Expected to be completed in 2020.
Fact: The distribution system is made up of an extensive grid of water mains stretching a staggering 6,500 miles!
See the video below about Water Tunnel 3 from November 2013.
4. Ever see the water towers on tall buildings in NYC?
4. Ever see the water towers on tall buildings in NYC?
…and into your home
…and into your home
Finally, the water arrives into your home. If you live in a building that’s less than six stories high, gravity will do all the work. But if not, then the pumps in your building help to move the water to the top floors.
5. The maintaining and future of NYC Water supply tunnels
5. The maintaining and future of NYC Water supply tunnels
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