Lake Mahopac Dam
Key Takeaway
Lake Mahopac Dam is classified as high hazard in New York. It was completed in 1940 and is 86 years old. Its primary use is recreation. 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 | 9 ft (taller than 9% in NY) |
| Dam Length | 190 ft |
| Dam Type | Earth |
| Max Storage | 17.9K acre-ft |
| Normal Storage | 16.7K acre-ft |
| Surface Area | 583 acres |
| Drainage Area | 2 sq mi |
| Max Discharge | 109 cfs |
| Year Completed | 1940 (86 years old) |
| NID ID | NY01329 |
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
TOWN OF CARMEL
Local Government
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Low Hazard 13 ftFrequently Asked Questions
What is the hazard classification of Lake Mahopac Dam?
Lake Mahopac Dam 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 Lake Mahopac Dam?
Lake Mahopac Dam is owned by TOWN OF CARMEL (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Lake Mahopac Dam built?
Lake Mahopac Dam was completed in 1940, making it 86 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 Lake Mahopac Dam?
Lake Mahopac Dam serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Lake Mahopac Dam?
Lake Mahopac Dam 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 Lake Mahopac Dam last inspected?
Lake Mahopac Dam was last inspected on April 23, 2019. Inspection dates indicate when a formal review occurred, not the results of that inspection.