Willimantic Reservoir Dam
Willimantic Reservoir Dam is a concrete dam located in Windham County, Connecticut, built in 1885. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Willimantic Reservoir Dam
The primary purpose of Willimantic Reservoir 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 Willimantic Water Works Dept. (local government). It impounds the Natchaug River near Willimantic.
The dam stands 29 feet tall and stretches 491 feet across, creates a reservoir covering 100 acres, has a maximum storage capacity of 1,670 acre-feet, and collects water from a drainage area of 166 square miles. Completed in 1885, the structure is over a century 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 11/02/2023.
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 Connecticut 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 | Connecticut |
| County | Windham |
| Nearest City | Willimantic |
| River/Stream | Natchaug River |
| Coordinates | 41.74046, -72.19485 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 29 ft |
| Dam Height | 29 ft |
| Dam Length | 491.3 ft |
| Year Completed | 1885 (141 years old) |
Storage & Hydraulics
| NID Storage | 1,670 acre-ft |
| Max Storage | 1,670 acre-ft |
| Normal Storage | 750 acre-ft |
| Surface Area | 100 acres |
| Drainage Area | 166 sq mi |
| Max Discharge | 38,125 cfs |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Willimantic Water Works Dept. |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 11/02/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CT00198 |
| Federal ID | CT00198 |
| More Info | State Dam Safety Program |