Black Rock Dam
Black Rock Dam is a rockfill dam located in Litchfield County, Connecticut, built in 1971. It carries a High hazard potential classification.
About Black Rock Dam
The primary purpose of Black Rock 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 Branch Brook near Waterbury.
The dam stands 130 feet tall and stretches 933 feet across, creates a reservoir covering 21 acres, has a maximum storage capacity of 8,450 acre-feet, and collects water from a drainage area of 20 square miles. Completed in 1971, 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 10/25/2023.
At 130 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 | Waterbury |
| River/Stream | Branch Brook |
| Coordinates | 41.65764, -73.10541 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 130 ft |
| Dam Height | 130 ft |
| Dam Length | 933 ft |
| Year Completed | 1971 (55 years old) |
Storage & Hydraulics
| NID Storage | 8,450 acre-ft |
| Max Storage | 8,450 acre-ft |
| Normal Storage | 305 acre-ft |
| Surface Area | 21 acres |
| Drainage Area | 20 sq mi |
| Max Discharge | 33,500 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 | 10/25/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CT00508 |
| Federal ID | CT00508 |
| More Info | State Dam Safety Program |