Great Pond Dam
Great Pond Dam is an earth dam located in Norfolk County, Massachusetts, built in 1945. It carries a High hazard potential classification and has a fair condition assessment.
About Great Pond Dam
The primary purpose of Great Pond Dam is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Tri-town Water Board (local government). It impounds the Norroway Brook near Braintree.
The dam stands 10 feet tall and stretches 2,000 feet across, creates a reservoir covering 206 acres, has a maximum storage capacity of 2,227 acre-feet, and collects water from a drainage area of 6 square miles. Completed in 1945, 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 08/18/2020.
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 | Norfolk |
| Nearest City | Braintree |
| River/Stream | Norroway Brook |
| Coordinates | 42.20576, -71.04434 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 10 ft |
| Dam Length | 2,000 ft |
| Year Completed | 1945 (81 years old) |
Storage & Hydraulics
| NID Storage | 2,227 acre-ft |
| Max Storage | 2,227 acre-ft |
| Normal Storage | 1,650 acre-ft |
| Surface Area | 206 acres |
| Drainage Area | 6 sq mi |
| Max Discharge | 467 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Tri-Town Water Board |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 08/18/2020 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MA00828 |
| Federal ID | MA00828 |
| More Info | State Dam Safety Program |