Effley

Beaver River· Lewis, New York· Built 1902· Concrete· 30 ft tall

High Hazard Hydroelectric Private

Key Takeaway

Effley is classified as high hazard in New York. It was completed in 1902 and is 124 years old. Its primary use is hydroelectric. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Height	30 ft (taller than 78.3% in NY)
Dam Length	1,247 ft
Dam Type	Concrete
Max Storage	3.1K acre-ft
Normal Storage	3.1K acre-ft

Surface Area	340 acres
Drainage Area	249 sq mi
Max Discharge	17,300 cfs
Year Completed	1902 (124 years old)
NID ID	NY00302

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

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

Emergency Action Plan: Yes

Last Inspection: August 9, 2022

State Regulated: No

Ownership

Erie Boulevard Hydropower, L.P.

Private

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Elmer

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Taylorville - North Dam

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Soft Maple Terminal

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Belfort

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Eagle

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Crystal Lake Dike

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High Falls - Dike No. 1

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Croghan Island Dam

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Frequently Asked Questions

What is the hazard classification of Effley?

Effley is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Effley?

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

When was Effley built?

Effley was completed in 1902, making it 124 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 Effley?

Effley 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 Effley?

Effley has a dam height of 30 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 Effley last inspected?

Effley was last inspected on August 9, 2022. 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.