Department of Environmental Conservation

D E C banner

Catskill Watershed Program - Summer 2009 - Protecting NYC drinking water

(by James Tierney, Assisstant Commissioner for Water Resources)

The New York City Watershed is a treasure. While a beautiful home for many, it serves as the source of high quality drinking water for nine million New Yorkers, eight million of whom receive it as an unfiltered water supply. It comprises only 4.2 percent of the land area of the state. Much of the Catskill Park and Forest Preserve lies within the Watershed. The system is an engineering marvel - providing approximately 1.2 billion gallons of drinking water each day through a gravity powered system of 19 reservoirs and hundreds of miles of aqueducts that stretch 125 miles north and west of New York City.

A comprehensive protection and water quality enhancement program is being actively implemented to protect the public health long term. The 1997 New York City Watershed Memorandum of Agreement (MOA) embodies a partnership to keep the Watershed's water clean and maintain economic vitality. It was joined by New York State, New York City, the EPA, 80 upstate Watershed communities and key environmental organizations. "Filtration avoidance," made possible by this partnership, saves water rate payers an estimated $8 billion in construction costs, and $1 million each day in operation and maintenance.

The quality of New York City's drinking water continues to be high but the Watershed is so fragile that real risks remain without this working partnership.

New York City's land acquisition program is one of the cornerstones of the protection program. Nearly 110,000 acres of high-priority lands have been acquired by the City and the State of New York has protected another 200,000 acres in the Watershed. While substantial, this is only 31 percent of the Watershed, an amount far below other major unfiltered systems. A dramatic increase in the parcelization of land is also setting the stage for development that, over time, could seriously impair the waters.

Impressive protection efforts include the fact that nearly all waste-water treatment plants within the Catskill and Delaware portions of the Watershed have been upgraded to the most stringent level, "tertiary treatment with micro-filtration and phosphorus treatment." The City has completed five new wastewater treatment plants. Read also in this edition about the many important accomplishments of the Catskill Watershed Corporation and the Watershed Agricultural Council.

Many challenges yet remain. "Turbidity" problems in the Watershed's Catskill portion continue to be a major threat to meeting filtration avoidance criteria. Turbid water from the Ashokan Reservoir, in particular, can potentially enter City water distribution, violating standards that trigger the highly expensive filtration requirement. Active efforts are underway to meet this challenge, but more intense storms projected from climate change cause concern.

Nutrient phosphorus, with the associated algae blooms, is another major risk. Fully eight of the 19 reservoirs in the Watershed are designated as impaired by excess phosphorus, violating state and federal water quality standards. Excess algae increases the transport of pathogens and interferes with the effectiveness of drinking water disinfection. When this organic matter is chlorinated, it often reacts to create a whole class of unhealthful, regulated chemicals, or "disinfection by-products." Governor David Patterson has proposed legislation to substantially reduce the phosphorus content of lawn fertilizers and in dishwashing detergents which, if enacted, would benefit the Watershed and all waters of our state.

I have been proud and grateful to be part of the partnership to protect the Watershed for this and future generations. Undoubtedly, it is a national model.

  • Links Leaving DEC's Website
  • PDF Help
  • For help with PDFs on this page, please call 518-402-8180.
  • Contact for this Page
  • Department of Environmental Conservation
    Division of Water, 4th Floor
    625 Broadway
    Albany, NY 12233-3500
    Send us an email
  • This Page Covers
  • Page applies to all NYS regions