Mascoma Lake Dam
Key Takeaway
Mascoma Lake Dam is classified as high hazard in New Hampshire. It was completed in 1881 and is 145 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 | 18 ft (taller than 63.5% in NH) |
| Dam Length | 575 ft |
| Dam Type | Concrete |
| Max Storage | 18.3K acre-ft |
| Normal Storage | 8.3K acre-ft |
| Surface Area | 1,155 acres |
| Drainage Area | 153 sq mi |
| Max Discharge | 17,255 cfs |
| Year Completed | 1881 (145 years old) |
| Year Modified | 2002 |
| NID ID | NH00153 |
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
NH DES WATER DIVISION
State Government
Nearby Dams
Harris Brook Reservoir Dam
Grafton, NH
Significant Hazard 22 ftMontcalm Golf Club Dam
Grafton, NH
Low Hazard 27 ftBaltic Mills Dam
Grafton, NH
Low Hazard 21 ftLebanon Water Treatment Intake Dam
Grafton, NH
Significant Hazard 16 ftFerson Pond Dam
Grafton, NH
Low Hazard 7 ftHanover Center Reservoir Dam
Grafton, NH
High Hazard 30 ftSmith Pond Dam
Grafton, NH
High Hazard 12 ftRivermill Mascoma Hydro Dam
Grafton, NH
High Hazard 22 ftFrequently Asked Questions
What is the hazard classification of Mascoma Lake Dam?
Mascoma 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 Mascoma Lake Dam?
Mascoma Lake Dam is owned by NH DES WATER DIVISION (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Mascoma Lake Dam built?
Mascoma Lake Dam was completed in 1881, making it 145 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 Mascoma Lake Dam?
Mascoma Lake 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 Mascoma Lake Dam?
Mascoma Lake Dam has a dam height of 18 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 Mascoma Lake Dam last inspected?
Mascoma Lake Dam was last inspected on October 31, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.