Upper Porter Pond Dam is an earth dam located in Plymouth County, Massachusetts, built in 1940. It carries a Significant hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 12 ft12 ft tall and 340 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 Upper Porter Pond Dam
The primary purpose of Upper Porter Pond Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by City of Brockton (local government). It impounds the Salisbury Brook & Salisbury Plain River near Brockton.
The dam stands 12 feet tall and stretches 340 feet across, creates a reservoir covering 11 acres, has a maximum storage capacity of 79 acre-feet, and collects water from a drainage area of 3 square miles. Completed in 1940, 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. An emergency action plan is in place for this dam. The most recent inspection on record was 11/07/2022.
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Location
| State | Massachusetts |
| County | Plymouth |
| Nearest City | Brockton |
| River/Stream | Salisbury Brook & Salisbury Plain River |
| Coordinates | 42.10176, -71.04322 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 12 ft |
| Dam Length | 340 ft |
| Year Completed | 1940 (86 years old) |
Storage & Hydraulics
| NID Storage | 79 acre-ft |
| Max Storage | 79 acre-ft |
| Normal Storage | 28 acre-ft |
| Surface Area | 11 acres |
| Drainage Area | 3 sq mi |
| Max Discharge | 370 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | City of Brockton |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 11/07/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MA00425 |
| Federal ID | MA00425 |
| More Info | State Dam Safety Program |