Deferiet

Black River· Jefferson, New York· Built 1899· Buttress· 18 ft tall
Low Hazard Hydroelectric Private

Key Takeaway

Deferiet is classified as low hazard in New York. It was completed in 1899 and is 127 years old. Its primary use is hydroelectric.

Physical Details

Dam Height 18 ft (taller than 49.5% in NY)
Dam Length695 ft
Dam TypeButtress
Max Storage405 acre-ft
Normal Storage405 acre-ft
Surface Area70 acres
Drainage Area1,817 sq mi
Max Discharge45,000 cfs
Year Completed1899 (127 years old)
NID IDNY00297

Safety Information

Low Hazard

No probable loss of human life and low economic/environmental losses expected.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: No
Last Inspection: August 9, 2019
State Regulated: No

Ownership

Erie Boulevard Hydropower, L.P.

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Deferiet?

Deferiet is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Deferiet?

Deferiet is owned by Erie Boulevard Hydropower, L.P. (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Deferiet built?

Deferiet was completed in 1899, making it 127 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Deferiet?

Deferiet serves the following purposes: Hydroelectric. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Deferiet?

Deferiet has a dam height of 18 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Deferiet last inspected?

Deferiet was last inspected on August 9, 2019. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.