Flat Rock
Key Takeaway
Flat Rock is classified as high hazard in New York. It was completed in 1925 and is 101 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 | 67 ft (taller than 95.9% in NY) |
| Dam Length | 568 ft |
| Dam Type | Concrete |
| Max Storage | 3.4K acre-ft |
| Normal Storage | 3.4K acre-ft |
| Surface Area | 228 acres |
| Drainage Area | 262 sq mi |
| Max Discharge | 12,000 cfs |
| Year Completed | 1925 (101 years old) |
| NID ID | NY00413 |
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
Nearby Dams
Browns Falls
St. Lawrence, NY
High Hazard 69 ftTwin Lakes Dam
St. Lawrence, NY
Low Hazard 7 ftNewton Falls Stabilization Pond #4 Dam
St. Lawrence, NY
Low Hazard 35 ftNewton Falls Stabilization Pond #3 Dam
St. Lawrence, NY
Low Hazard 22 ftNewton Falls Lower
St. Lawrence, NY
Low Hazard 25 ftNewton Falls Upper
St. Lawrence, NY
High Hazard 21 ftBenson Mines Plant Dam
St. Lawrence, NY
Low Hazard 38 ftChaumont Swamp Dam
St. Lawrence, NY
Low Hazard 100 ftFrequently Asked Questions
What is the hazard classification of Flat Rock?
Flat Rock 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 Flat Rock?
Flat Rock is owned by Erie Boulevard Hydropower, L.P. (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Flat Rock built?
Flat Rock was completed in 1925, making it 101 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 Flat Rock?
Flat Rock 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 Flat Rock?
Flat Rock has a dam height of 67 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 Flat Rock last inspected?
Flat Rock was last inspected on June 15, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.