Plymouth Reservoir Dam
Plymouth Reservoir Dam is an earth dam located in Litchfield County, Connecticut, built in 1881. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Plymouth Reservoir Dam
The primary purpose of Plymouth 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 Town Of Plymouth (local government). It impounds the Naugatuck River Trib near Thomaston.
The dam stands 20 feet tall and stretches 730 feet across, creates a reservoir covering 36 acres, has a maximum storage capacity of 390 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1881, 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 10/01/2021.
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 Trib |
| Coordinates | 41.68487, -73.05263 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 20 ft |
| Dam Height | 20 ft |
| Dam Length | 730 ft |
| Year Completed | 1881 (145 years old) |
Storage & Hydraulics
| NID Storage | 390 acre-ft |
| Max Storage | 390 acre-ft |
| Normal Storage | 290 acre-ft |
| Surface Area | 36 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 408 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Town of Plymouth |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/01/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CT00286 |
| Federal ID | CT00286 |
| More Info | State Dam Safety Program |