Mirror Lake Dam is an earth dam located in Grafton County, New Hampshire, built in 1836. It carries a Low hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 12 ft12 ft tall and 290 ft long. 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 Mirror Lake Dam
The primary purpose of Mirror Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Nh Des Water Division (state). It impounds the Tr Hubbard Brook near Woodstock.
The dam stands 12 feet tall and stretches 290 feet across, creates a reservoir covering 38 acres, has a maximum storage capacity of 187 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1836, the structure is one of the older dams in the region, with over a century and a half of service.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected 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 09/20/2022.
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Location
| State | New Hampshire |
| County | Grafton |
| Nearest City | Woodstock |
| River/Stream | Tr Hubbard Brook |
| Coordinates | 43.94050, -71.69110 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 12 ft |
| Dam Height | 12 ft |
| Dam Length | 290 ft |
| Year Completed | 1836 (190 years old) |
Storage & Hydraulics
| NID Storage | 187 acre-ft |
| Max Storage | 187 acre-ft |
| Normal Storage | 136 acre-ft |
| Surface Area | 38 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 215 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Nh Des Water Division |
| Owner Type | State |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 09/20/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NH00317 |
| Federal ID | NH00317 |
| More Info | State Dam Safety Program |