Thirty Acre Pond Dam
Thirty Acre Pond Dam is an earth dam located in Plymouth County, Massachusetts, built in 1936. It carries a High hazard potential classification and has a fair condition assessment.
About Thirty Acre Pond Dam
The primary purpose of Thirty Acre 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 And Salisbury Plain River near Brockton.
The dam stands 12 feet tall and stretches 600 feet across, creates a reservoir covering 27 acres, has a maximum storage capacity of 230 acre-feet, and collects water from a drainage area of 4 square miles. Completed in 1936, the structure is well-established, with more than 75 years of service.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. 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 11/14/2022.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Massachusetts dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Massachusetts |
| County | Plymouth |
| Nearest City | Brockton |
| River/Stream | Salisbury Brook And Salisbury Plain River |
| Coordinates | 42.09361, -71.04653 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 12 ft |
| Dam Length | 600 ft |
| Year Completed | 1936 (90 years old) |
Storage & Hydraulics
| NID Storage | 230 acre-ft |
| Max Storage | 230 acre-ft |
| Normal Storage | 125 acre-ft |
| Surface Area | 27 acres |
| Drainage Area | 4 sq mi |
| Max Discharge | 83 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | City of Brockton |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 11/14/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MA00423 |
| Federal ID | MA00423 |
| More Info | State Dam Safety Program |