Lower Mountain Lake Dam is an earth dam located in Grafton County, New Hampshire, built in 1967. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 33 ft33 ft tall and 850 ft long, taller than 76% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Lower Mountain Lake Dam
The primary purpose of Lower Mountain Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Mountain Lakes Village District (local government). It impounds the Waterman Brook near Haverhill.
The dam stands 33 feet tall and stretches 850 feet across, creates a reservoir covering 41 acres, has a maximum storage capacity of 376 acre-feet, and collects water from a drainage area of 3 square miles. Completed in 1967, the structure is well into its service life at over 50 years old.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 04/27/2021.
At 33 feet, this dam is taller than 76% of dams nationwide.
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Location
| State | New Hampshire |
| County | Grafton |
| Nearest City | Haverhill |
| River/Stream | Waterman Brook |
| Coordinates | 44.12685, -71.96069 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 33 ft |
| Dam Height | 33 ft |
| Dam Length | 850 ft |
| Year Completed | 1967 (59 years old) |
Storage & Hydraulics
| NID Storage | 376 acre-ft |
| Max Storage | 376 acre-ft |
| Normal Storage | 191 acre-ft |
| Surface Area | 41 acres |
| Drainage Area | 3 sq mi |
| Max Discharge | 1,650 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Mountain Lakes Village District |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 04/27/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NH00195 |
| Federal ID | NH00195 |
| More Info | State Dam Safety Program |