Johnsonville
Key Takeaway
Johnsonville is classified as high hazard in New York. It was completed in 1909 and is 117 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 | 39 ft (taller than 87.6% in NY) |
| Dam Length | 529 ft |
| Dam Type | Concrete |
| Max Storage | 6.4K acre-ft |
| Normal Storage | 6.4K acre-ft |
| Surface Area | 450 acres |
| Drainage Area | 604 sq mi |
| Max Discharge | 11,000 cfs |
| Year Completed | 1909 (117 years old) |
| NID ID | NY00119 |
Safety Information
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?
Ownership
Erie Boulevard Hydropower, L.P.
Private
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What is the hazard classification of Johnsonville?
Johnsonville 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 Johnsonville?
Johnsonville is owned by Erie Boulevard Hydropower, L.P. (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Johnsonville built?
Johnsonville was completed in 1909, making it 117 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 Johnsonville?
Johnsonville 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 Johnsonville?
Johnsonville has a dam height of 39 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 Johnsonville last inspected?
Johnsonville was last inspected on July 20, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.