Poquonnock Reservoir Dam
Key Takeaway
Poquonnock Reservoir Dam is classified as high hazard in Connecticut. It was completed in 1901 and is 125 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 | 18 ft (taller than 67.8% in CT) |
| Dam Length | 290 ft |
| Dam Type | Earth |
| Max Storage | 1.7K acre-ft |
| Normal Storage | 921 acre-ft |
| Surface Area | 139 acres |
| Drainage Area | 16 sq mi |
| Max Discharge | 1,160 cfs |
| Year Completed | 1901 (125 years old) |
| NID ID | CT00231 |
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 Groton
Local Government
Nearby Dams
Poquonock Lake Dam
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Low Hazard 7 ftMorgan Pond Dam
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Significant Hazard 45 ftPerry Pond Dam
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Significant Hazard 13 ftBrandagee Lake Dam
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Significant Hazard 15 ftFrequently Asked Questions
What is the hazard classification of Poquonnock Reservoir Dam?
Poquonnock 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 Poquonnock Reservoir Dam?
Poquonnock Reservoir Dam is owned by City of Groton (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Poquonnock Reservoir Dam built?
Poquonnock Reservoir Dam was completed in 1901, making it 125 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 Poquonnock Reservoir Dam?
Poquonnock 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 Poquonnock Reservoir Dam?
Poquonnock Reservoir Dam has a dam height of 18 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 Poquonnock Reservoir Dam last inspected?
Poquonnock Reservoir Dam was last inspected on January 26, 2018. Inspection dates indicate when a formal review occurred, not the results of that inspection.