DATABASE: Dig into the Adirondack Park’s 500+ dams

Look up the dams on your favorite Adirondack rivers

By Zachary Matson

The state documents over 500 dams in the Adirondack Park. Presenting different risks to public safety, many haven’t been inspected in decades or at all.

Below is a database compiled by the Adirondack Explorer using the website Airtable. The database includes details from the state Department of Environmental Conservation dam inventory, as well as insepction reports and engineering documents for some structures obtained through the state Freedom of Information Law.

While the state inventory lists over 1,300 dams in the 12 counties that comprise the Adirondack Park, the below database only includes those within the Blue Line.

You can group the dams by hazard rating or county; search by name, owner or river; compare heights and lengths; research uses and construction types; examine inspections reports; and read hundreds of pages of engineering studies of some of the region’s high hazard dams.

Here are the hazard defintions used to classify dams in the state:

• Class “A” or “Low Hazard” dam: A dam failure is unlikely to result in damage to anything more than isolated or unoccupied buildings, undeveloped lands, minor roads such as town or county roads; is unlikely to result in the interruption of important utilities, including water supply, sewage treatment, fuel, power, cable or telephone infrastructure; and/or is otherwise unlikely to pose the threat of personal injury, substantial economic loss or substantial environmental damage.
• Class “B” or “Intermediate Hazard” dam: A dam failure may result in damage to isolated homes, main highways, and minor railroads; may result in the interruption of important utilities, including water supply, sewage treatment, fuel, power, cable or telephone infrastructure; and/or is otherwise likely to pose the threat of personal injury and/or substantial economic loss or substantial environmental damage. Loss of human life is not expected.
• Class “C” or “High Hazard” dam: A dam failure may result in widespread or serious damage to home(s); damage to main highways, industrial or commercial buildings, railroads, and/or important utilities, including water supply, sewage treatment, fuel, power, cable or telephone infrastructure; or substantial environmental damage; such that the loss of human life or widespread substantial economic loss is likely.
• Class “D” or “Negligible or No Hazard” dam: A dam that has been breached or removed, or has failed or otherwise no longer materially impounds waters, or a dam that was planned but never constructed. Class “D” dams are considered to be defunct dams posing negligible or no hazard. The department may retain pertinent records regarding such dams.

(Warning: some of the data included in the state inventory is outdated or inaccurate.)

Go forth and explore!

The average dam in New York is 86 years old, compared to the national average of 57 years, according to the 2022 Report Card for America’s Infrastructure produced by the American Society of Civil Engineers. “New York’s dams are significantly older than those across the rest of the United States and many of them were built before modern design standards,” the organization wrote. Adirondack dams are even older, nearly 90 years old on average.