Wishon Auxiliary No. 1
Key Takeaway
Wishon Auxiliary No. 1 is classified as significant hazard in California. It was completed in 1958 and is 68 years old. Its primary use is hydroelectric. Significant hazard means failure could cause economic or environmental damage. Learn more.
Physical Details
| Dam Height | 26 ft (taller than 24.8% in CA) |
| Dam Length | 220 ft |
| Dam Type | Concrete |
| Max Storage | 133.6K acre-ft |
| Normal Storage | 129.1K acre-ft |
| Surface Area | 1,025 acres |
| Drainage Area | 177 sq mi |
| Max Discharge | 52,000 cfs |
| Year Completed | 1958 (68 years old) |
| NID ID | CA00411 |
Safety Information
No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
Pacific Gas and Electric Company
Private
Nearby Dams
Frequently Asked Questions
What is the hazard classification of Wishon Auxiliary No. 1?
Wishon Auxiliary No. 1 is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Wishon Auxiliary No. 1?
Wishon Auxiliary No. 1 is owned by Pacific Gas and Electric Company (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Wishon Auxiliary No. 1 built?
Wishon Auxiliary No. 1 was completed in 1958, making it 68 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 Wishon Auxiliary No. 1?
Wishon Auxiliary No. 1 serves the following purposes: Hydroelectric. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Wishon Auxiliary No. 1?
Wishon Auxiliary No. 1 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 Wishon Auxiliary No. 1 last inspected?
Wishon Auxiliary No. 1 was last inspected on August 17, 2023. Inspection dates indicate when a formal review occurred, not the results of that inspection.