Gonic Dam is a concrete dam located in Strafford County, New Hampshire, built in 1935. It carries a Significant hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 16 ft16 ft tall and 130 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic concrete gravity section and the water level is illustrative.
About Gonic Dam
The primary purpose of Gonic Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Gosport Properties LLC (private). It impounds the Cocheco River near Rochester.
The dam stands 16 feet tall and stretches 130 feet across, creates a reservoir covering 18 acres, has a maximum storage capacity of 700 acre-feet, and collects water from a drainage area of 78 square miles. Completed in 1935, the structure is well-established, with more than 75 years of service.
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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. The most recent inspection on record was 06/01/2020.
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Location
| State | New Hampshire |
| County | Strafford |
| Nearest City | Rochester |
| River/Stream | Cocheco River |
| Coordinates | 43.27330, -70.97770 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 16 ft |
| Dam Height | 16 ft |
| Dam Length | 130 ft |
| Year Completed | 1935 (91 years old) |
Storage & Hydraulics
| NID Storage | 700 acre-ft |
| Max Storage | 700 acre-ft |
| Normal Storage | 60 acre-ft |
| Surface Area | 18 acres |
| Drainage Area | 78 sq mi |
| Max Discharge | 6,300 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Gosport Properties LLC |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 06/01/2020 |
| Emergency Action Plan | No |
Identifiers
| NID ID | NH00388 |
| Federal ID | NH00388 |
| More Info | State Dam Safety Program |