Grassy Pond Dam is a concrete dam located in Merrimack County, New Hampshire, built in 1836. It carries a Low hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 9 ft9 ft tall and 75 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 Grassy Pond Dam
The primary purpose of Grassy Pond Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Nh Fish and Game Department (state). It impounds the Intermittent Stream near Hopkinton.
The dam stands 9 feet tall and stretches 75 feet across, creates a reservoir covering 35 acres, has a maximum storage capacity of 204 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 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 03/31/2020.
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Location
| State | New Hampshire |
| County | Merrimack |
| Nearest City | Hopkinton |
| River/Stream | Intermittent Stream |
| Coordinates | 43.21609, -71.77473 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 9 ft |
| Dam Height | 9 ft |
| Dam Length | 75 ft |
| Year Completed | 1836 (190 years old) |
Storage & Hydraulics
| NID Storage | 204 acre-ft |
| Max Storage | 204 acre-ft |
| Normal Storage | 79 acre-ft |
| Surface Area | 35 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 565 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Nh Fish and Game Department |
| Owner Type | State |
| Hazard Classification | Low |
| Condition Assessment | Fair |
| Last Inspection | 03/31/2020 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | NH00418 |
| Federal ID | NH00418 |
| More Info | State Dam Safety Program |