Thermalito Forebay
Key Takeaway
Thermalito Forebay is classified as high hazard in California. It was completed in 1967 and is 59 years old. Its primary use is hydroelectric. 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 | 91 ft (taller than 79.8% in CA) |
| Dam Length | 15,900 ft |
| Dam Type | Earth |
| Max Storage | 11.8K acre-ft |
| Normal Storage | 11.8K acre-ft |
| Surface Area | 630 acres |
| Drainage Area | 5 sq mi |
| Max Discharge | 5,000 cfs |
| Year Completed | 1967 (59 years old) |
| NID ID | CA00041 |
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
California Department of Water Resources
State Government
Nearby Dams
Fish Barrier
Butte, CA
Low Hazard 61 ftThermalito Diversion
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High Hazard 143 ftA. L. Chaffin
Butte, CA
Low Hazard 65 ftThermalito Afterbay
Butte, CA
High Hazard 39 ftCannon Ranch
Butte, CA
Significant Hazard 17 ftBidwell Bar Canyon Saddle
Butte, CA
High Hazard 47 ftMiner'S Ranch
Butte, CA
High Hazard 55 ftLake Wyandotte
Butte, CA
High Hazard 46 ftFrequently Asked Questions
What is the hazard classification of Thermalito Forebay?
Thermalito Forebay 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 Thermalito Forebay?
Thermalito Forebay is owned by California Department of Water Resources (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Thermalito Forebay built?
Thermalito Forebay was completed in 1967, making it 59 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 Thermalito Forebay?
Thermalito Forebay serves the following purposes: Hydroelectric, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Thermalito Forebay?
Thermalito Forebay has a dam height of 91 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 Thermalito Forebay last inspected?
Thermalito Forebay was last inspected on August 29, 2023. Inspection dates indicate when a formal review occurred, not the results of that inspection.