Quabbin Winsor Dam
Quabbin Winsor Dam is an earth dam located in Hampshire County, Massachusetts, built in 1939. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Quabbin Winsor Dam
The primary purpose of Quabbin Winsor 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 Ma Department Of Conservation & Recreation (state). It impounds the Swift River near Ware.
The dam stands 170 feet tall and stretches 2,640 feet across, creates a reservoir covering 25,216 acres, has a maximum storage capacity of 1,810,000 acre-feet, and collects water from a drainage area of 187 square miles. Completed in 1939, 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 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 10/31/2022.
At 170 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 | Hampshire |
| Nearest City | Ware |
| River/Stream | Swift River |
| Coordinates | 42.28130, -72.34583 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 170 ft |
| Dam Length | 2,640 ft |
| Year Completed | 1939 (87 years old) |
Storage & Hydraulics
| NID Storage | 1,810,000 acre-ft |
| Max Storage | 1,810,000 acre-ft |
| Normal Storage | 1,265,200 acre-ft |
| Surface Area | 25,216 acres |
| Drainage Area | 187 sq mi |
| Max Discharge | 27,500 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | MA Department of Conservation & Recreation |
| Owner Type | State |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/31/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MA00588 |
| Federal ID | MA00588 |
| More Info | State Dam Safety Program |