Foss Valley
Key Takeaway
Foss Valley is classified as high hazard in California. It was completed in 1988 and is 38 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 | 56 ft (taller than 65.1% in CA) |
| Dam Length | 2,500 ft |
| Dam Type | Earth |
| Max Storage | 800 acre-ft |
| Surface Area | 31 acres |
| Year Completed | 1988 (38 years old) |
| NID ID | CA01268 |
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
Atlas Peak Vineyards
Private
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High Hazard 49 ftFrequently Asked Questions
What is the hazard classification of Foss Valley?
Foss 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 Foss Valley?
Foss Valley is owned by Atlas Peak Vineyards (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Foss Valley built?
Foss Valley was completed in 1988, making it 38 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 Foss Valley?
Foss Valley serves the following purposes: Water Supply, Irrigation, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Foss Valley?
Foss Valley has a dam height of 56 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 Foss Valley last inspected?
Foss Valley was last inspected on March 16, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.