Lost Valley
Key Takeaway
Lost Valley is classified as high hazard in Idaho. It was completed in 1910 and is 116 years old. Its primary use is other. 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 | 31 ft (taller than 58.6% in ID) |
| Dam Length | 262 ft |
| Normal Storage | 9.6K acre-ft |
| Surface Area | 633 acres |
| Drainage Area | 29 sq mi |
| Max Discharge | 505 cfs |
| Year Completed | 1910 (116 years old) |
| Year Modified | 1938 |
| NID ID | ID00255 |
Safety Information
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?
Ownership
Private
Frequently Asked Questions
What is the hazard classification of Lost Valley?
Lost Valley 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 Lost Valley?
Lost Valley is owned by information not available (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Lost Valley built?
Lost Valley 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 Lost Valley?
Lost Valley serves the following purposes: Other. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Lost Valley?
Lost Valley has a dam height of 31 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 Lost Valley last inspected?
Lost Valley was last inspected on June 18, 2019. Inspection dates indicate when a formal review occurred, not the results of that inspection.