Minidoka South Dike

SNAKE RIVER TR· Cassia, Idaho· Built 1906· Rockfill· 21 ft tall
High Hazard Recreation Hydroelectric Irrigation Federal Government

Key Takeaway

Minidoka South Dike is classified as high hazard in Idaho. It was completed in 1906 and is 120 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 21 ft (taller than 30.8% in ID)
Dam Length788 ft
Dam TypeRockfill
Max Storage220.2K acre-ft
Normal Storage210.2K acre-ft
Surface Area12,400 acres
Drainage Area15,625 sq mi
Year Completed1906 (120 years old)
NID IDID00275

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: April 23, 2020
State Regulated: Yes
Regulatory Agency: IDWR

Ownership

RECLAMATION

Federal Government

Frequently Asked Questions

What is the hazard classification of Minidoka South Dike?

Minidoka South Dike 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 Minidoka South Dike?

Minidoka South Dike is owned by RECLAMATION (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Minidoka South Dike built?

Minidoka South Dike was completed in 1906, making it 120 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 Minidoka South Dike?

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

How tall is Minidoka South Dike?

Minidoka South Dike has a dam height of 21 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 Minidoka South Dike last inspected?

Minidoka South Dike was last inspected on April 23, 2020. 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.