Mann Creek

MANN CREEK· Washington, Idaho· Built 1966· Earth· 148 ft tall
High Hazard Irrigation Federal Government

Key Takeaway

Mann Creek is classified as high hazard in Idaho. It was completed in 1966 and is 60 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 148 ft (taller than 96.9% in ID)
Dam Length1,176 ft
Dam TypeEarth
Max Storage15.4K acre-ft
Normal Storage13.0K acre-ft
Surface Area283 acres
Drainage Area56 sq mi
Max Discharge3,885 cfs
Year Completed1966 (60 years old)
NID IDID00285

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 2, 2020
State Regulated: Yes
Regulatory Agency: IDWR

Ownership

RECLAMATION

Federal Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Mann Creek?

Mann Creek 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 Mann Creek?

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

When was Mann Creek built?

Mann Creek was completed in 1966, making it 60 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 Mann Creek?

Mann Creek 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 Mann Creek?

Mann Creek has a dam height of 148 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 Mann Creek last inspected?

Mann Creek was last inspected on July 2, 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.