Lewiston
Key Takeaway
Lewiston is classified as high hazard in California. It was completed in 1963 and is 63 years old. Its primary use is water supply. 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 | 73 ft (taller than 74.1% in CA) |
| Dam Length | 745 ft |
| Dam Type | Earth |
| Max Storage | 14.7K acre-ft |
| Normal Storage | 14.7K acre-ft |
| Surface Area | 750 acres |
| Drainage Area | 719 sq mi |
| Max Discharge | 0 cfs |
| Year Completed | 1963 (63 years old) |
| NID ID | CA10165 |
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
RECLAMATION
Federal Government
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Lewiston?
Lewiston 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 Lewiston?
Lewiston is owned by RECLAMATION (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Lewiston built?
Lewiston was completed in 1963, making it 63 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 Lewiston?
Lewiston serves the following purposes: Water Supply. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Lewiston?
Lewiston has a dam height of 73 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 Lewiston last inspected?
Lewiston was last inspected on September 28, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.