Lyonsdale - Dam No. 2

Moose River· Lewis, New York· Built 1935· Concrete· 9 ft tall
Low Hazard Hydroelectric Private

Key Takeaway

Lyonsdale - Dam No. 2 is classified as low hazard in New York. It was completed in 1935 and is 91 years old. Its primary use is hydroelectric.

Physical Details

Dam Height 9 ft (taller than 9% in NY)
Dam Length34 ft
Dam TypeConcrete
Max Storage50 acre-ft
Normal Storage50 acre-ft
Surface Area9 acres
Drainage Area426 sq mi
Year Completed1935 (91 years old)
NID IDNY12234

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: September 19, 2019
State Regulated: No

Ownership

Lyonsdale Associates, LLC

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Lyonsdale - Dam No. 2?

Lyonsdale - Dam No. 2 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 Lyonsdale - Dam No. 2?

Lyonsdale - Dam No. 2 is owned by Lyonsdale Associates, LLC (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Lyonsdale - Dam No. 2 built?

Lyonsdale - Dam No. 2 was completed in 1935, making it 91 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 Lyonsdale - Dam No. 2?

Lyonsdale - Dam No. 2 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 Lyonsdale - Dam No. 2?

Lyonsdale - Dam No. 2 has a dam height of 9 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 Lyonsdale - Dam No. 2 last inspected?

Lyonsdale - Dam No. 2 was last inspected on September 19, 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.