Patterson
Key Takeaway
Patterson is classified as high hazard in California. It was completed in 1960 and is 66 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 | 37 ft (taller than 41.5% in CA) |
| Dam Length | 435 ft |
| Dam Type | Earth |
| Max Storage | 350 acre-ft |
| Surface Area | 29 acres |
| Drainage Area | 1 sq mi |
| Year Completed | 1960 (66 years old) |
| NID ID | CA01050 |
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
Lake Oaks Community
Private
Nearby Dams
Shaffer
El Dorado, CA
Significant Hazard 33 ftVolo Mining Company
El Dorado, CA
High Hazard 35 ftHoliday Lake
El Dorado, CA
Significant Hazard 39 ftGastaldi
El Dorado, CA
Low Hazard 36 ftChili Bar
El Dorado, CA
High Hazard 126 ftCross Creek Ranch
El Dorado, CA
Low Hazard 23 ftIndian Creek
El Dorado, CA
High Hazard 36 ftBig Canyon Creek
El Dorado, CA
Low Hazard 63 ftFrequently Asked Questions
What is the hazard classification of Patterson?
Patterson 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 Patterson?
Patterson is owned by Lake Oaks Community (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Patterson built?
Patterson was completed in 1960, making it 66 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 Patterson?
Patterson 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 Patterson?
Patterson has a dam height of 37 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 Patterson last inspected?
Patterson was last inspected on May 10, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.