Upper Ansonia Reservoir Dam
Key Takeaway
Upper Ansonia Reservoir Dam is classified as high hazard in Connecticut. It was completed in 1887 and is 139 years old. Its primary use is water supply. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.
Physical Details
| Dam Height | 21 ft (taller than 76.6% in CT) |
| Dam Length | 345 ft |
| Dam Type | Masonry |
| Max Storage | 310 acre-ft |
| Normal Storage | 196 acre-ft |
| Surface Area | 34 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 240 cfs |
| Year Completed | 1887 (139 years old) |
| NID ID | CT00029 |
Safety Information
Loss of human life is likely if the dam fails.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
City of Derby
Local Government
Nearby Dams
Lower Ansonia Reservoir Dam
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Significant Hazard 3 ftShelton Reservoir #2 Dam
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Significant Hazard 35 ftFrequently Asked Questions
What is the hazard classification of Upper Ansonia Reservoir Dam?
Upper Ansonia Reservoir Dam is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Upper Ansonia Reservoir Dam?
Upper Ansonia Reservoir Dam is owned by City of Derby (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Upper Ansonia Reservoir Dam built?
Upper Ansonia Reservoir Dam was completed in 1887, making it 139 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 Upper Ansonia Reservoir Dam?
Upper Ansonia Reservoir Dam serves the following purposes: Water Supply. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Upper Ansonia Reservoir Dam?
Upper Ansonia Reservoir Dam has a dam height of 21 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 Upper Ansonia Reservoir Dam last inspected?
Upper Ansonia Reservoir Dam was last inspected on August 5, 2015. Inspection dates indicate when a formal review occurred, not the results of that inspection.