Mianus River Dam
Key Takeaway
Mianus River Dam is classified as significant hazard in Connecticut. It was completed in 1920 and is 106 years old. Its primary use is recreation. Significant hazard means failure could cause economic or environmental damage. Learn more.
Physical Details
| Dam Height | 20 ft (taller than 72.5% in CT) |
| Dam Length | 350 ft |
| Dam Type | Concrete |
| Max Storage | 525 acre-ft |
| Normal Storage | 525 acre-ft |
| Surface Area | 48 acres |
| Drainage Area | 31 sq mi |
| Max Discharge | 10,158 cfs |
| Year Completed | 1920 (106 years old) |
| NID ID | CT00045 |
Safety Information
No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
Town of Greenwich
Local Government
Nearby Dams
Cos Cob Pond Dam
Fairfield, CT
Significant Hazard 8 ftEast Pond Dam
Fairfield, CT
Significant Hazard 18 ftMilbrook Upper Lake Dam
Fairfield, CT
Significant Hazard 14 ftDublin Hill Dam
Fairfield, CT
Significant Hazard 9 ftMianus Filter Plant Dam
Fairfield, CT
High Hazard 31 ftRidgeview Pond Dam
Fairfield, CT
Significant Hazard 10 ftDingletown Road Dam
Fairfield, CT
Significant Hazard 7 ftFrye Lake Dam
Fairfield, CT
Significant Hazard 10 ftFrequently Asked Questions
What is the hazard classification of Mianus River Dam?
Mianus River Dam is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Mianus River Dam?
Mianus River Dam is owned by Town of Greenwich (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Mianus River Dam built?
Mianus River Dam was completed in 1920, making it 106 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.
What is the primary purpose of Mianus River Dam?
Mianus River Dam serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Mianus River Dam?
Mianus River Dam has a dam height of 20 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.
When was Mianus River Dam last inspected?
Mianus River Dam was last inspected on April 27, 2016. Inspection dates indicate when a formal review occurred, not the results of that inspection.