Lake Ralphine
Key Takeaway
Lake Ralphine is classified as high hazard in California. It was completed in 1882 and is 144 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 | 35 ft (taller than 38.2% in CA) |
| Dam Length | 700 ft |
| Dam Type | Earth |
| Max Storage | 387 acre-ft |
| Surface Area | 19 acres |
| Drainage Area | 0 sq mi |
| Year Completed | 1882 (144 years old) |
| NID ID | CA00882 |
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
City of Santa Rosa
Local Government
Nearby Dams
Santa Rosa Creek Reservoir
Sonoma, CA
High Hazard 37 ftMiddle Fork Brush Creek
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High Hazard 37 ftPiner Creek
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High Hazard 28 ftAnnadel No. 1
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High Hazard 67 ftMatanzas Creek
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High Hazard 95 ftFountaingrove
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High Hazard 38 ftSalinger
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Low Hazard 46 ftThe Hill Ranch
Sonoma, CA
High Hazard 49 ftFrequently Asked Questions
What is the hazard classification of Lake Ralphine?
Lake Ralphine 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 Lake Ralphine?
Lake Ralphine is owned by City of Santa Rosa (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Lake Ralphine built?
Lake Ralphine was completed in 1882, making it 144 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 Lake Ralphine?
Lake Ralphine serves the following purposes: Water Supply, Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.
How tall is Lake Ralphine?
Lake Ralphine has a dam height of 35 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 Lake Ralphine last inspected?
Lake Ralphine was last inspected on December 1, 2021. Inspection dates indicate when a formal review occurred, not the results of that inspection.