First Connecticut Lake Dam
Key Takeaway
First Connecticut Lake Dam is classified as high hazard in New Hampshire. It was completed in 1930 and is 96 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 | 56 ft (taller than 95.8% in NH) |
| Dam Length | 1,117 ft |
| Dam Type | Earth |
| Max Storage | 114.0K acre-ft |
| Normal Storage | 76.5K acre-ft |
| Surface Area | 3,125 acres |
| Drainage Area | 83 sq mi |
| Year Completed | 1930 (96 years old) |
| NID ID | NH00186 |
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
GREAT RIVER HYDRO LLC
Private
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Low Hazard 25 ftSecond Connecticut Lake Dam
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Low Hazard 28 ftFrequently Asked Questions
What is the hazard classification of First Connecticut Lake Dam?
First Connecticut Lake 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 First Connecticut Lake Dam?
First Connecticut Lake Dam is owned by GREAT RIVER HYDRO LLC (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was First Connecticut Lake Dam built?
First Connecticut Lake Dam was completed in 1930, making it 96 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 First Connecticut Lake Dam?
First Connecticut Lake Dam 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 First Connecticut Lake Dam?
First Connecticut Lake Dam has a dam height of 56 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 First Connecticut Lake Dam last inspected?
First Connecticut Lake Dam was last inspected on August 24, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.