Jacobs Pond Dam is an earth dam located in Plymouth County, Massachusetts, built in 1730. It carries a Significant hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 11 ft11 ft tall and 650 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 Jacobs Pond Dam
The primary purpose of Jacobs Pond Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Town of Norwell (local government). It impounds the Third Herring Brook near Norwell.
The dam stands 11 feet tall and stretches 650 feet across, creates a reservoir covering 55 acres, has a maximum storage capacity of 650 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1730, the structure is one of the older dams in the region, with over a century and a half 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. An emergency action plan is in place for this dam. The most recent inspection on record was 06/11/2021.
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Location
| State | Massachusetts |
| County | Plymouth |
| Nearest City | Norwell |
| River/Stream | Third Herring Brook |
| Coordinates | 42.15823, -70.84738 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 11 ft |
| Dam Length | 650 ft |
| Year Completed | 1730 (296 years old) |
Storage & Hydraulics
| NID Storage | 650 acre-ft |
| Max Storage | 650 acre-ft |
| Normal Storage | 110 acre-ft |
| Surface Area | 55 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 520 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Town of Norwell |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 06/11/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MA00365 |
| Federal ID | MA00365 |
| More Info | State Dam Safety Program |