Kelly Dam

RATTLESNAKE CREEK· Beaverhead, Montana· Built 1965· Earth· 26 ft tall

High Hazard Irrigation Private

Key Takeaway

Kelly Dam is classified as high hazard in Montana. It was completed in 1965 and is 61 years old. Its primary use is irrigation. 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	26 ft (taller than 77.8% in MT)
Dam Length	230 ft
Dam Type	Earth
Max Storage	850 acre-ft
Normal Storage	614 acre-ft

Surface Area	44 acres
Drainage Area	25 sq mi
Max Discharge	1,240 cfs
Year Completed	1965 (61 years old)
NID ID	MT01563

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: July 6, 2023

State Regulated: Yes

Regulatory Agency: DNRC

Ownership

RATTLESNAKE RESERVOIR CO

Private

Nearby Dams

Tub Lake Dam

Beaverhead, MT

Significant Hazard 13 ft

Pear Lake Dam

Beaverhead, MT

High Hazard 19 ft

Boot Lake Dam

Beaverhead, MT

High Hazard 27 ft

Deerhead Lake Dam

Beaverhead, MT

Significant Hazard 13 ft

Anchor South Dam

Beaverhead, MT

High Hazard 11 ft

Bond Lake Dam

Beaverhead, MT

Low Hazard 16 ft

Frequently Asked Questions

What is the hazard classification of Kelly Dam?

Kelly 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 Kelly Dam?

Kelly Dam is owned by RATTLESNAKE RESERVOIR CO (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Kelly Dam built?

Kelly Dam was completed in 1965, making it 61 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 Kelly Dam?

Kelly Dam serves the following purposes: Irrigation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Kelly Dam?

Kelly Dam has a dam height of 26 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 Kelly Dam last inspected?

Kelly Dam was last inspected on July 6, 2023. 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.