Three Mile Reservoir Dam
Key Takeaway
Three Mile Reservoir Dam is classified as high hazard in New Hampshire. It was completed in 1986 and is 40 years old. Its primary use is flood risk reduction. 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 | 20 ft (taller than 70.9% in NH) |
| Dam Length | 292 ft |
| Dam Type | Concrete |
| Max Storage | 620 acre-ft |
| Normal Storage | 250 acre-ft |
| Surface Area | 9 acres |
| Drainage Area | 5 sq mi |
| Max Discharge | 8,000 cfs |
| Year Completed | 1986 (40 years old) |
| NID ID | NH00736 |
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
CITY OF KEENE DPW
Local Government
Nearby Dams
Goose Pond Dike
Cheshire, NH
Low Hazard 8 ftOtter Brook Dam
Cheshire, NH
High Hazard 119 ftGoose Pond Dam
Cheshire, NH
High Hazard 22 ftRobinhood Park Reservoir Dam
Cheshire, NH
High Hazard 18 ftAshuelot River Dam
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Low Hazard 16 ftBabbidge Reservoir Dam
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High Hazard 38 ftSurry Mountain Dam
Cheshire, NH
High Hazard 83 ftRodgers Pond Dam
Cheshire, NH
Low Hazard 14 ftFrequently Asked Questions
What is the hazard classification of Three Mile Reservoir Dam?
Three Mile Reservoir 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 Three Mile Reservoir Dam?
Three Mile Reservoir Dam is owned by CITY OF KEENE DPW (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Three Mile Reservoir Dam built?
Three Mile Reservoir Dam was completed in 1986, making it 40 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 Three Mile Reservoir Dam?
Three Mile Reservoir Dam serves the following purposes: Flood Risk Reduction. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Three Mile Reservoir Dam?
Three Mile Reservoir Dam has a dam height of 20 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 Three Mile Reservoir Dam last inspected?
Three Mile Reservoir Dam was last inspected on June 23, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.