Mount Sunapee Sewage Lagoon Dam is an earth dam located in Merrimack County, New Hampshire, built in 1973. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 22 ft22 ft tall and 1,300 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 Mount Sunapee Sewage Lagoon Dam
Mount Sunapee Sewage Lagoon Dam is a dam in Merrimack, New Hampshire. The dam is owned by Mount Sunapee Resort (state). It impounds the Na near Newbury.
The dam stands 22 feet tall and stretches 1,300 feet across, creates a reservoir covering 2 acres, and has a maximum storage capacity of 14 acre-feet. Completed in 1973, 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. The most recent inspection on record was 10/20/2021.
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Location
| State | New Hampshire |
| County | Merrimack |
| Nearest City | Newbury |
| River/Stream | Na |
| Coordinates | 43.33610, -72.07690 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 22 ft |
| Dam Height | 22 ft |
| Dam Length | 1,300 ft |
| Year Completed | 1973 (53 years old) |
Storage & Hydraulics
| NID Storage | 14 acre-ft |
| Max Storage | 14 acre-ft |
| Normal Storage | 14 acre-ft |
| Surface Area | 2 acres |
Ownership & Safety
| Purpose | Other |
| Owner | Mount Sunapee Resort |
| Owner Type | State |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/20/2021 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | NH00800 |
| Federal ID | NH00800 |
| More Info | State Dam Safety Program |