Alexander DeLuca, M.D.
Addiction, Pain, & Public Health website  
[Home] [Library]  [Slides]  [Search]  [Medline]  [Links]
Statement of Purpose; Privacy policy; Statement of Ownership; Statement of Sponsorship; Advertising policy 

The Croton Watershed:
an Argument for Collaborative Resource Management

by Alexander DeLuca, M.D., Originally posted: February 19, 2003; Most recently revised: May 14, 2005. This paper was written as an assignment for the Course P6300: Environment Sciences, Columbia University Mailman School of Public Health, Professor Brandt-Rauf,


By the end of the 18th century, NYC faced an environmental crisis. The Collect, a forty-eight acre fresh water pond where the Tombs now stands, once a potable water supply some 50 feet deep, had become so hopelessly polluted and overused that it was no longer able to support even the demands of municipal firefighters.
[Mankiewicz, 1998] Without a sewage system, most of the city’s wells had become polluted. Ravaged by fire and repeated outbreaks of cholera, yellow fever and typhoid, a reliable water supply was desperately needed.

Civil engineer John Jervis began work on the Croton Dam in 1836, and six years later ninety million gallons of water a day began flowing into Yorkville Reservoir (currently the Great Lawn) in Central Park through an aqueduct approximately 40 miles long.
[SoutheastMuseum, 2003] In the late 1890's additional dams and a second Croton Aqueduct were constructed, and capacity increased to almost 400 million gallons a day. The original aqueduct served the City continuously until 1955 and it remains operational serving the Town of Ossining. Eventually the Delaware and Catskill water systems were built, and today the 2000 square mile NYC watershed, though threatened by development, supplies 1.4 billion gallons of high quality, unfiltered, affordable, fresh drinking water to the people of lower New York State. The New Croton Aqueduct serves the South Bronx, Harlem and parts of the East Side. [Thomas, 1994]

Common Ground
Clean drinking water is a priority at all levels of society.

The people who live in the NYC watershed rate clean drinking water as the most important social problem and have demonstrated a willingness to support governmental efforts to protect and enhance it. In 1999, EMPACT, an interagency Presidential Initiative, conducted a survey of the general public. Among the findings for Region 2, which includes the NYC watershed:

1. Respondents considered environmental issues as more important than non-environmental issues,

2. Of local environmental concerns, water issues were primary.
[EMPACT, 2000]

And the citizenry are highly organized. Locally, the Bronx Council for Environmental Quality and the Croton Watershed Clean Water Coalition (CWCWC) have taken the lead in advocating for Croton watershed maintenance and restoration programs, and these are backed by diverse groups including block and community associations, local and regional chapters of the Audubon Society, Trout Unlimited, the Sierra Club, and Riverkeeper, among others.

The federal government is also committed to clean drinking water, and it has developed elaborate policies that it aggressively pursues. The Safe Water Drinking Act of 1974 forms the basis of federal regulation of public water systems. In 1989 the EPA promulgated the Surface Water Treatment Rules (SWTR) to limit the publics exposure to waterborne pathogens and make it’s Total Coliform Rule more stringent. [Kramer, 1996]

The State has likewise demonstrated that protection of the watershed is a top priority. On 5/23/2002 the Army Corps of Engineers, concluding a process begun by Governor Pataki, officially designated all waters east of the Hudson River as Critical Resource Waters (CRW). CRW status compels attention to source protection and strengthens enforcement of regulations already in place. The result is that stricter standards must be met prior to any development activity in the watershed. [CWCWC, 2002]

[Top of Page]

Finally, the City, after manifesting little enthusiasm under Mayor Giuliani for the difficult political and legal work necessary to protect the watershed, has become fully involved. It was encouraged, perhaps, by the necessity of dealing with a law suit brought against it by the EPA in 1997 to force the building of a filtration system for the watershed. The settlement was a City, State, and Federal "Watershed Agreement" in which the NYC Department of Environmental Protection (NYCDEP) agreed to build a filtration plant for the Croton watershed. Since then the NYCDEP has embarked on a plan to purchase land within the Catskill and Delaware systems to avoid having to filter them; perhaps wrongly, it did not seek a filtration waiver for the Croton system at that time.

The Controversy
There is a choice in how to ensure clean drinking water and protect the watershed: either build a billion dollar filtration facility in a densely populated area where the aqueduct enters the City, or protect and enhance the ecological structures that are already accomplishing the same function naturally. "The question is what to trust: nature's diverse and widespread capacities, or one centralized technological filtration facility?"
[Mankiewicz, 1998]

A Critique of Filtration

Current EPA policy is embodied in the 1989 Surface Water Treatment Rules (SWTR), which require that all surface sources of drinking water be filtered unless municipalities establish that they meet all standards for water quality and "show control of the watershed." The policy is extremely focused, considering only whether a filtration plant need be built or not. Mankiewicz
[1998] has criticized the SWTR as being "all or nothing" and based on "no rational criteria." He criticizes the Rules for not specifying measurable criteria as to when surface water needs to be filtered, and for failing to recognize the reality of biogeochemical purification. Further, "control of the watershed" is ambiguous and is defined neither in terms of land usage nor ecologically, but only in terms of ownership. This has significant implications and consequences. For example, the lands comprising the Croton system are approximately 25 percent managed forest, but the EPA considers these in exactly the same way it would if the area was entirely paved.

[Top of Page]

The EPA's position is that the Croton watershed is stressed from development and in danger of failure. Certainly, the rate of growth of the counties that comprise the Croton system is dramatic. Between 1990 and 1998 Putnam County was the fastest growing county in the State with a population increase of 11.2 percent. It grew from 56,00 people in 1970 to approximately 94,000 in 1998, and this growth has continued to accelerate in the new millennium.
[Rae, 1999] Despite this growth and development, the EPA's equation of ‘ownership equals development’ and ‘development equals degraded water quality’ is not supported by the their own analysis of the data. From their "Filtration Avoidance Determination Mid-Course Review" released in 2000:

"Water quality data analysis shows that fecal coliform levels, turbidity and disinfectant byproduct levels are all within acceptable limits. NYCDEP has never incurred a monthly maximum contaminant level violation… [and] monitoring has shown that adequate disinfectant concentrations are being maintained." [EPA, 2000]
In essence, the Rules do not admit the possibility of a community stewardship that protects and enhances water quality. They represent a failure to understand that the health of a watershed is determined not by ownership, per se, but rather by how the land is managed, how land usage is prioritized, and toward what end.

Filtration systems are complex, centralized, industrial plants that require continuous maintenance and monitoring. Though promoted specifically to limit exposure to infectious agents, such plants cannot completely eliminate water borne disease outbreaks (WBDOs). First, not all pathogens are susceptible to current detection and treatment technology. Giardia and enteric pathogens are the usual targets for determining adequacy of treatment, but other common pathogens are not routinely or easily discovered. The most important such is Cryptosporida, which was found to be more common than Shigella and almost as common as Salmonella in a two-year prospective study conducted in 1985. [Meinhardt, 1996] None of the technologies widely in use is completely effective at inactivating and removing Cryptosporidum oocysts. "[Even] when multiple barriers are operating efficiently, oocysts may break through a treatment system..." [Meinhardt, 1996]

And when treatment systems fail, they can become a contributing factor in WBDOs. Filtration plants concentrate the pathogens that they remove, and can become a reservoir in the life cycle of the pathogen. [Meinhardt, 1996] If operational lapses or frank filtration failure occurs, the results can be dramatic. For example, in 1967 a WBDO of some 13,000 cases occurred in Georgia in a filtered water supply due to "operational irregularities" in the filtration system; Cryptosporidium oocytes were detected in 38% of the stool specimens associated with this outbreak. In 1993 Wisconsin experienced 800 confirmed cases of cryptosporidiosis and an estimated additional 400,000 cases of diarrhea due to inadequate removal of oocysts by the coagulation/filtration process in use. [Meinhardt, 1996]

[Top of Page]

Finally, there are serious social and political problems with centralized filtration water treatment systems. As large and complex industrial plants that take many years to build and which operate in close proximity to the communities they serve, they arouse NIMBYism and are difficult to site. Cost is another problem, especially in the current environment of massive City and State budget deficits. But perhaps the most important negative and far-reaching social consequence is subtler. Compared to the dispersed installations and varied practices employed in the soil/watershed alternative (SWA), centralized filtration systems are disempowering by their very nature. Rather than collectively sharing responsibility for nurturing a watershed, the citizenry tend to rely passively on an industrial plant to assure quality drinking water.

The Soil/Watershed Alternative
Everyone, including the EPA and the NYCDEP, agrees that water quality in the Croton system meets federal standards and a well-organized and articulate coalition of community and environmental groups, scientists, and lawyers feel there is no need to build anything on the scale of a billion dollar filtration plant. The alternative is to let nature, in the form of Croton's 300-odd square miles of soil, do the purification work

The SWA is a collection of decentralized, redundant, low-cost, mostly landscape-based installations placed throughout the watershed. These are designed to collectively maximize the amount of rainwater and runoff that enter the soil, and to increase both the hydroperiod contact time and filter contact time. [Mankiewicz, 1998] The strategy is to connect street and land runoff with streams, wetlands, forests and meadows and to allow nature to filter and biogeochemically neutralize pathogens and chemical toxins. Such an approach depends on intensive and continuous monitoring of environmental markers and water quality, rigorous policing of business and household water use and waste practices, and vigorous enforcement of environmental regulations. Resource management expertise, adequate staffing levels, sufficient alignment of goals, and stakeholder leadership skills are necessary for successful collaborative watershed management. [Henly, 2002] This level of community involvement and collaboration seems daunting in the abstract, and is considered by some a drawback of this approach.

I would argue, however, that this combination of a common goal, scientific and technical expertise, and capable stakeholder groups with experience working with each other exists right now in the Croton region. The NYC watershed is the largest, unfiltered, surface water system in the nation, and it sits in a densely populated and rapidly growing area. We have a historic opportunity to demonstrate that sustainable development, development coexisting with watershed protection and enhancement, is achievable through collaborative resource management.

[Top of Page]


1 EMPACT (2000). Local Urban Environmental Issues Study of 86 Metropolitan Areas - Region 2. Environmental Protection Agency. (accessed February 14, 2003).

2 Environmental Protection Agency (2000). Filtration Avoidance Determination - Mid-Course Review. (accessed February 15, 2003).

3 Environmental Protection Agency (2003). EPA Order Against NYC Points Out Need to Filter Croton Water Supply. (accessed February 15, 2003).

4 SoutheastMuseum (2002). The Croton Water System. SoutheastMuseum org. (accessed February 16, 2003).

5 Akhter, M.N., Levy, M.E., Bodie, C.M.R., Donegan, N., Griffith, B., Jones, M., and Stair, P.O. (1994). Assessment of Inadequately Filtered Public Drinking Water — Washington, D.C., December 1993. MMWR CDC Epidemiologic Notes and Reports, 43, 661-669. (accessed February 15, 2003).

6 Croton Watershed Clean Water Coalition (2002). Critical Resource Waters Designation Given to all East-Of-Hudson New York City Reservoirs, Including Tributaries and Wetlands. (accessed February 14, 2003).

7 Henly, R.K. (2002). An Institutional Analysis Framework For Collaborative Watershed Management Efforts. The Watershed Management Council. (accessed February 16, 2003).

8 Kennedy, R.F., Sullivan, M., and Postman, M.B. (1999). Watershed for Sale: Explosive Development Threatens New York City's Drinking Water Supply. Riverkeeper, Inc. (accessed February 14, 2003).

9 Kramer, M.H., Herwaldt, B.L., Craun, G.F., Calderon, R.L., and Juranek, D.D. (1996). Surveillance for Waterborne-Disease Outbreaks - United States, 1993-1994. MMWR CDC Surveillance Summary, 45, 1-33. (accessed February 15, 2003).

10 Mankiewicz, P.S. (1998). Can We Drink the Water We Live With? - New Yorkers struggle to let nature do the job. Whole Earth Magazine, Summer 1998. (accessed February 14, 2003).

11 Meinhardt, P.L., Casemore, D.P., and Miller, K.B. (1996). Epidemiologic Aspects of Human Cryptosporidiosis and the Role of Water borne Transmission. Epidemiologic Reviews, 18, 118-136.

12 Rae, L. and Henderson, T. (1999). Putnam Leads State in Growth. Journal News, Section A, pg 1.

13 Thomas, J. (1994). Algae Bloom Shuts Down Croton Aqueduct. New York Times, Section B, pg 3.



Dr. DeLuca's Addiction, Pain, and Public Health Website

Alexander DeLuca, M.D., FASAM.

[Top of Page]

Originally posted:  2/19/2003

All website Email to:

Statement of Purpose; Privacy policy; Statements of Confidentiality, Ownership, & Sponsorship; Advertising policy

Most recently revised: 5/14/2005
Copyright © 2003 All rights reserved.

We subscribe to the HONcode principles of the HON Foundation. Click to   This website is in compliance with the HONcode. Pin # = HONConduct911193. Verify HONcode Status We subscribe to the HONcode principles of the HON Foundation. Click to