Macallen Dam
Key Takeaway
Macallen Dam is classified as high hazard in New Hampshire. It was completed in 1887 and is 139 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 | 27 ft (taller than 83.7% in NH) |
| Dam Length | 150 ft |
| Dam Type | Concrete |
| Max Storage | 1.7K acre-ft |
| Normal Storage | 480 acre-ft |
| Surface Area | 120 acres |
| Drainage Area | 211 sq mi |
| Max Discharge | 10,930 cfs |
| Year Completed | 1887 (139 years old) |
| Year Modified | 2021 |
| NID ID | NH00365 |
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 NEWMARKET
Local Government
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High Hazard 17 ftFrequently Asked Questions
What is the hazard classification of Macallen Dam?
Macallen 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 Macallen Dam?
Macallen Dam is owned by TOWN OF NEWMARKET (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Macallen Dam built?
Macallen Dam was completed in 1887, making it 139 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 Macallen Dam?
Macallen 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 Macallen Dam?
Macallen Dam has a dam height of 27 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 Macallen Dam last inspected?
Macallen Dam was last inspected on August 2, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.