Lake Monomonac Dam
Lake Monomonac Dam is an earth dam located in Worcester County, Massachusetts. It carries a High hazard potential classification and has a fair condition assessment.
About Lake Monomonac Dam
The primary purpose of Lake Monomonac 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 Winchendon (local government). It impounds the North Branch Of Millers River near Winchendon.
The dam stands 16 feet tall and stretches 250 feet across, creates a reservoir covering 595 acres, has a maximum storage capacity of 4,340 acre-feet, and collects water from a drainage area of 18 square miles.
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 11/22/2022.
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 | Worcester |
| Nearest City | Winchendon |
| River/Stream | North Branch Of Millers River |
| Coordinates | 42.70060, -72.00061 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 16 ft |
| Dam Length | 250 ft |
Storage & Hydraulics
| NID Storage | 4,340 acre-ft |
| Max Storage | 4,340 acre-ft |
| Normal Storage | 1,880 acre-ft |
| Surface Area | 595 acres |
| Drainage Area | 18 sq mi |
| Max Discharge | 675 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Town of Winchendon |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 11/22/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MA00631 |
| Federal ID | MA00631 |
| More Info | State Dam Safety Program |