Upper Mianus River Dam
Upper Mianus River Dam is a masonry dam located in Fairfield County, Connecticut, built in 1930. It carries a Significant hazard potential classification.
About Upper Mianus River Dam
The primary purpose of Upper Mianus River Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Ruth Spelke Est (private). It impounds the Mianus River near Stamford.
The dam stands 3 feet tall and stretches 60 feet across, creates a reservoir covering 18 acres, has a maximum storage capacity of 72 acre-feet, and collects water from a drainage area of 70 square miles. Completed in 1930, the structure is well-established, with more than 75 years of service.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life.
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Location
| State | Connecticut |
| County | Fairfield |
| Nearest City | Stamford |
| River/Stream | Mianus River |
| Coordinates | 41.11812, -73.60344 |
Physical Characteristics
| Dam Type | Masonry |
| NID Height | 3 ft |
| Dam Height | 3 ft |
| Dam Length | 60 ft |
| Year Completed | 1930 (96 years old) |
Storage & Hydraulics
| NID Storage | 72 acre-ft |
| Max Storage | 72 acre-ft |
| Normal Storage | 72 acre-ft |
| Surface Area | 18 acres |
| Drainage Area | 70 sq mi |
| Max Discharge | 810 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Ruth Spelke Est |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not Rated |
| Emergency Action Plan | No |
Identifiers
| NID ID | CT01703 |
| Federal ID | CT01703 |
| More Info | State Dam Safety Program |