Adder Reservoir
Key Takeaway
Adder Reservoir is classified as high hazard in Connecticut. It was completed in 1934 and is 92 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 | 28 ft (taller than 85.5% in CT) |
| Dam Length | 700 ft |
| Dam Type | Earth |
| Max Storage | 306 acre-ft |
| Normal Storage | 306 acre-ft |
| Surface Area | 34 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 349 cfs |
| Year Completed | 1934 (92 years old) |
| Year Modified | 1974 |
| NID ID | CT00139 |
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 Middletown
Local Government
Nearby Dams
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Significant Hazard 17 ftFrequently Asked Questions
What is the hazard classification of Adder Reservoir?
Adder Reservoir 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 Adder Reservoir?
Adder Reservoir is owned by City of Middletown (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Adder Reservoir built?
Adder Reservoir was completed in 1934, making it 92 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 Adder Reservoir?
Adder Reservoir 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 Adder Reservoir?
Adder Reservoir has a dam height of 28 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 Adder Reservoir last inspected?
Adder Reservoir was last inspected on October 8, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.