Thomaston Dam
Thomaston Dam is a rockfill dam located in Litchfield County, Connecticut, built in 1960. It carries a High hazard potential classification.
About Thomaston Dam
The primary purpose of Thomaston Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Usace - New England District (federal). It impounds the Naugatuck River near Thomaston.
The dam stands 137 feet tall and stretches 2,000 feet across, creates a reservoir covering 1 acres, has a maximum storage capacity of 63,000 acre-feet, and collects water from a drainage area of 97 square miles. Completed in 1960, 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. An emergency action plan is in place for this dam. The most recent inspection on record was 11/14/2023.
At 137 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 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 | Litchfield |
| Nearest City | Thomaston |
| River/Stream | Naugatuck River |
| Coordinates | 41.69502, -73.06231 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 137 ft |
| Dam Height | 137 ft |
| Dam Length | 2,000 ft |
| Year Completed | 1960 (66 years old) |
Storage & Hydraulics
| NID Storage | 63,000 acre-ft |
| Max Storage | 63,000 acre-ft |
| Surface Area | 1 acres |
| Drainage Area | 97 sq mi |
| Max Discharge | 132,200 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | USACE - New England District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 11/14/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CT00501 |
| Federal ID | CT00501 |
| More Info | State Dam Safety Program |