Apthorp
Key Takeaway
Apthorp is classified as significant hazard in New Hampshire. It was completed in 1936 and is 90 years old. Its primary use is hydroelectric. Significant hazard means failure could cause economic or environmental damage. Learn more.
Physical Details
| Dam Height | 24 ft (taller than 79% in NH) |
| Dam Length | 235 ft |
| Dam Type | Concrete |
| Max Storage | 210 acre-ft |
| Normal Storage | 210 acre-ft |
| Surface Area | 20 acres |
| Drainage Area | 205 sq mi |
| Max Discharge | 14,800 cfs |
| Year Completed | 1936 (90 years old) |
| NID ID | NH00611 |
Safety Information
No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
White Mountain Hydroelectric Corporation
Private
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High Hazard 149 ftFrequently Asked Questions
What is the hazard classification of Apthorp?
Apthorp is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Apthorp?
Apthorp is owned by White Mountain Hydroelectric Corporation (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Apthorp built?
Apthorp was completed in 1936, making it 90 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 Apthorp?
Apthorp 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 Apthorp?
Apthorp has a dam height of 24 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 Apthorp last inspected?
Apthorp was last inspected on August 17, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.