Great Swamp Flood Control Dam
Great Swamp Flood Control Dam is a dam located in Fairfield County, Connecticut, built in 1979. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Great Swamp Flood Control Dam
The primary purpose of Great Swamp Flood Control 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 Connecticut Deep (state). It impounds the Ridgefield Brook near Ridgefield.
The dam stands 12 feet tall and stretches 276 feet across, creates a reservoir covering 134 acres, and collects water from a drainage area of 2 square miles. Completed in 1979, the structure is 47 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. 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 06/07/2023.
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 | Fairfield |
| Nearest City | Ridgefield |
| River/Stream | Ridgefield Brook |
| Coordinates | 41.29685, -73.49115 |
Physical Characteristics
| NID Height | 12 ft |
| Dam Height | 12 ft |
| Dam Length | 276 ft |
| Year Completed | 1979 (47 years old) |
Storage & Hydraulics
| Surface Area | 134 acres |
| Drainage Area | 2 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Connecticut DEEP |
| Owner Type | State |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 06/07/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CT05002 |
| Federal ID | CT05002 |
| More Info | State Dam Safety Program |