Great Hill Reservior Dam

FOURMILE BROOK· New Haven, Connecticut· Built 1909· Concrete· 41 ft tall
High Hazard Recreation Local Government

Key Takeaway

Great Hill Reservior Dam is classified as high hazard in Connecticut. It was completed in 1909 and is 117 years old. Its primary use is recreation. 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 41 ft (taller than 94.2% in CT)
Dam Length165 ft
Dam TypeConcrete
Max Storage378 acre-ft
Normal Storage360 acre-ft
Surface Area12 acres
Drainage Area3 sq mi
Max Discharge810 cfs
Year Completed1909 (117 years old)
NID IDCT00087

Safety Information

High Hazard

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?

Emergency Action Plan: Yes
Last Inspection: August 15, 2019
State Regulated: Yes
Regulatory Agency: DEEP

Ownership

Town of Seymour

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Great Hill Reservior Dam?

Great Hill Reservior 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 Great Hill Reservior Dam?

Great Hill Reservior Dam is owned by Town of Seymour (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Great Hill Reservior Dam built?

Great Hill Reservior Dam was completed in 1909, making it 117 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 Great Hill Reservior Dam?

Great Hill Reservior 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 Great Hill Reservior Dam?

Great Hill Reservior Dam has a dam height of 41 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 Great Hill Reservior Dam last inspected?

Great Hill Reservior Dam was last inspected on August 15, 2019. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.