Otter Rapids

Wisconsin River· Vilas, Wisconsin· Built 1907· Gravity· 20 ft tall
High Hazard Hydroelectric Recreation Public Utility

Key Takeaway

Otter Rapids is classified as high hazard in Wisconsin. It was completed in 1907 and is 119 years old. Its primary use is hydroelectric. 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 20 ft (taller than 60.1% in WI)
Dam Length474 ft
Dam TypeGravity
Max Storage42.3K acre-ft
Normal Storage42.3K acre-ft
Surface Area3,916 acres
Drainage Area535 sq mi
Max Discharge12,700 cfs
Year Completed1907 (119 years old)
NID IDWI00807

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 16, 2022
State Regulated: No

Ownership

Wisconsin Public Service Corporation

Public Utility

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Otter Rapids?

Otter Rapids 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 Otter Rapids?

Otter Rapids is owned by Wisconsin Public Service Corporation (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Otter Rapids built?

Otter Rapids was completed in 1907, making it 119 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 Otter Rapids?

Otter Rapids serves the following purposes: Hydroelectric, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Otter Rapids?

Otter Rapids has a dam height of 20 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 Otter Rapids last inspected?

Otter Rapids was last inspected on August 16, 2022. 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.