Northfield Mt. - Main Dam
Northfield Mt. - Main Dam is a rockfill dam located in Franklin County, Massachusetts, built in 1973. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Northfield Mt. - Main Dam
The primary purpose of Northfield Mt. - Main Dam is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Firstlight Power Services Llc (public utility). It impounds the Connecticut River near Farley.
The dam stands 145 feet tall and stretches 5,500 feet across, creates a reservoir covering 278 acres, has a maximum storage capacity of 21,500 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1973, the structure is well into its service life at over 50 years old.
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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 08/04/2022.
At 145 feet, this dam is taller than 99% of all dams in the United States.
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 | Franklin |
| Nearest City | Farley |
| River/Stream | Connecticut River |
| Coordinates | 42.61020, -72.43880 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 145 ft |
| Dam Height | 145 ft |
| Dam Length | 5,500 ft |
| Year Completed | 1973 (53 years old) |
Storage & Hydraulics
| NID Storage | 21,500 acre-ft |
| Max Storage | 21,500 acre-ft |
| Normal Storage | 17,050 acre-ft |
| Surface Area | 278 acres |
| Drainage Area | 1 sq mi |
| Spillway Type | None |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | FirstLight Power Services LLC |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 08/04/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MA00974 |
| Federal ID | MA00974 |
| More Info | State Dam Safety Program |