Bigfork Diversion Dam

Swan River· Flathead, Montana· Built 1910· Gravity· 22 ft tall

Key Takeaway

Bigfork Diversion Dam is classified as high hazard in Montana. It was completed in 1910 and is 116 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 22 ft (taller than 63.5% in MT)
Dam Length92 ft
Dam TypeGravity
Normal Storage109 acre-ft
Surface Area73 acres
Drainage Area736 sq mi
Year Completed1910 (116 years old)
NID IDMT00220

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 18, 2022
State Regulated: No

Ownership

PacifiCorp

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Bigfork Diversion Dam?

Bigfork Diversion 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 Bigfork Diversion Dam?

Bigfork Diversion Dam is owned by PacifiCorp (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Bigfork Diversion Dam built?

Bigfork Diversion Dam was completed in 1910, making it 116 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 Bigfork Diversion Dam?

Bigfork Diversion Dam serves the following purposes: Hydroelectric, Fish And Wildlife Pond, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Bigfork Diversion Dam?

Bigfork Diversion Dam has a dam height of 22 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 Bigfork Diversion Dam last inspected?

Bigfork Diversion Dam was last inspected on October 18, 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.