Willimantic Reservoir Dam

NATCHAUG RIVER· Windham, Connecticut· Built 1885· Concrete· 29 ft tall
High Hazard Water Supply Local Government

Key Takeaway

Willimantic Reservoir Dam is classified as high hazard in Connecticut. It was completed in 1885 and is 141 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 29 ft (taller than 86.8% in CT)
Dam Length491 ft
Dam TypeConcrete
Max Storage1.7K acre-ft
Normal Storage750 acre-ft
Surface Area100 acres
Drainage Area166 sq mi
Max Discharge38,125 cfs
Year Completed1885 (141 years old)
NID IDCT00198

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: October 8, 2019
State Regulated: Yes
Regulatory Agency: DEEP

Ownership

Willimantic Water Works Dept.

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Willimantic Reservoir Dam?

Willimantic 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 Willimantic Reservoir Dam?

Willimantic Reservoir Dam is owned by Willimantic Water Works Dept. (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Willimantic Reservoir Dam built?

Willimantic Reservoir Dam was completed in 1885, making it 141 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 Willimantic Reservoir Dam?

Willimantic 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 Willimantic Reservoir Dam?

Willimantic Reservoir Dam has a dam height of 29 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 Willimantic Reservoir Dam last inspected?

Willimantic Reservoir Dam was last inspected on October 8, 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.