State of the Planet

News from the Columbia Climate School

, ,

One Billion Gallons a Day, Naturally

By Samuel Barnes

There are myriad causes of New York’s rise and role as a central hub in the global human network.  By virtue of its geography, our city was a destination for generations of immigrants, a nexus for the natural assets of the Americas, and thanks to the countless geniuses who have graced its streets and shores New York developed into a center of wealth, of culture, of life and art and education.  It has retained and refined these faculties for over a century, and a hallmark of a true New Yorker is the grateful recognition that there is no place on Earth more happening than here.

A view of the Kensico Reservoir. Over 1 billion gallons per day flow into the city from its pristine reservoir system – Photo by Lauren

Less considered in the story of New York’s success is why the mighty City agglomerated here, in this little archipelago; even less is how it continues to operate and sustain such a high level of activity, growth, and quality of life for its 8-million-plus inhabitants.  Amongst New Yorkers it’s a trope to declare that we have some of the cleanest drinking water in the world—but the claim is true.  The water of New York, culled from a complicated network of upstate reservoirs, rivers and canals, is a silent partner in the superstructure of city life.  If not for the amazing feats of planning and engineering that provide access to this most essential resource, New York City would never have become the essential node in the many meshworks of the world that it so clearly is.

In New York’s early history, water was sourced from the ground: contemporary City Hall stands atop the famous Collect Pond, which was the main source of New York’s water up to the War of 1812.  The 19th-century city, quickly expanding and tired of the ill effects of using local water for all purposes (from sewage to washing to industry to drinking), constructed the Croton dam system, collecting water from the Croton reservoir in Westchester and channeling it to New York through canals and aqueducts.  The Central Park Aqueduct on 79th Street, long since retired, was the main dispersion point for this system in Manhattan.  But as the city continued its rapid growth and development accelerated upstate, an ambitious plan was hatched to bring even more water, of even higher caliber, from even farther away to the taps and faucets of the newly-incorporated City.

Beginning in 1907, New York City authorities began a program of purchase and annexation of vast swaths of land in the Catskills watershed.  Their plan was to construct a network of reservoirs, and build a 150-mile-long canal that would connect the new supply to the previously implemented Croton system.  After much wrangling with natives of Ulster and Orange counties over displacement of villages and properties as well as imposition new land-use laws that prohibited major agricultural or industrial development, work was begun on a system that when completed would consist of five brand new reservoirs: the Ashokan, the Schoharie, the Kensico, the Neversink, and the Roundout, and a total revamping of the existent Westchester supply chain.  When they came on-line in 1915, the new system supplied New York City with almost 800 million gallons per day of clean, pristine water.

With the construction of the Delaware system in 1950’s, the entirety of Manhattan, Brooklyn, and Queens’ water supply now comes from this area over a hundred miles distant from the city.  All of this water is unfiltered: the city authorities wholly rely on the natural quality of the water, simply sifting out particulate and adding minute amounts of anti-septic chemicals.  It is also gravity fed—the only pumping of your water occurs when it travels up from one of the three major tunnels that run deep beneath the city’s surface to your faucet.  With reference to scale, distance, longevity, and quality, there is no comparable water supply system anywhere.  New York City is home to the finest tap water in the world.

Beyond the feats of construction that enabled it (and continue to—the Third Tunnel, scheduled to go on line in 2013, is the largest, longest, and most expensive public works venture in the city’s history), our water system is not maintained by new technologies, development, or treatment: it is maintained by careful preservation.  The Catskills and Delaware systems remain able to supply safe and plentiful drinking water because they have been rigorously protected from hazardous development over the last century.  NYC’s Department of Environmental Protection monitors the conditions at over 50 stations in the million-acre watershed, and ensures that the rich natural landscape is able to retain its health and provide this essential asset for many years into the future.  The foresight that New York City displayed in recognizing that a well-maintained wilderness ecosystem can be an invaluable source of wealth has, quietly, been a major factor in the transformation of our humble Mid-Atlantic harbor into a global center of human life.

CERC provides a course on the sustainability of water, a critical issue facing society over the coming decades. Water resources are affected by changes not only in climate but also in population, economic growth, technological change, and other socioeconomic factors. In addition, successful water management must account for the importance of water for both human society and natural ecosystems. The objective of this course then is to examine water management issues in light of the expected climatic and socioeconomic changes that will occur during the twenty-first century. Students will be asked to think critically in order to answer questions related to sustainable development. The knowledge that students obtain from this course will ultimately allow them to make informed decisions on the sustainability of water resources.

This course is part of CERC’s Certificate Program in Conservation and Environmental Sustainability. This first session is free and open to the public. Registration is required to attend the full 10-hour course.

Courses may be taken on an individual basis or you may pursue the full 12-course Certificate. Interested in learning more? Visit our website or contact CERC for more information: or 212-854-0149.

Source: Anastasia Van Burkalow, The Geography of New York City’s Water Supply: A Study of Interactions. Geographical Review, Vol. 43 No. 3. 1959.

Samuel Barnes is an intern at the Center for Environmental Research and Conservation.

Banner featuring a collage of extreme heat images.

Recent record-breaking heat waves have affected communities across the world. The Extreme Heat Workshop will bring together researchers and practitioners to advance the state of knowledge, identify community needs, and develop a framework for evaluating risks with a focus on climate justice. Register by June 15

Notify of

Inline Feedbacks
View all comments
Richard Seager
Richard Seager
12 years ago

Yes, the NYC water supply system is a wonder. Our study of the precipitation history in the Catskills watershed – the 1960s drought and the wet climate that has followed – is described here:
I think the water supply is fairly well placed to withstand climate variability and climate change but these factors need to be considered – along with hydrofracking of course – in order to ensure good quality water for the city for ever more.

Samuel Barnes
Samuel Barnes
12 years ago

Wow, Richard– that is truly an impressive study. Thank you for the link.

When I visited the Neversink watershed last month we discussed the profound shift in precipitation patterns, particularly in light of Irene and Lee—I heard ‘hundred-year flood’ tossed around a few times.
Amazingly, throughout the entirety of the crisis virtually no water was softened or lost. New York’s water is exceedingly well-suited to withstand climate variability and change in that direction.

However, along with the potential horrors of Marcellus Shale, I agree with you in the assertion that a return to pre-60’s precipitation levels and certainly to the drought conditions of the 60’s constitute the greatest danger to the continuing success of our water supply system.