Lower Twin Lake
Key Takeaway
Lower Twin Lake is classified as low hazard in California. It was completed in 1985 and is 41 years old. Its primary use is water supply.
Physical Details
| Dam Height | 18 ft (taller than 12.6% in CA) |
| Dam Length | 1,080 ft |
| Dam Type | Earth |
| Max Storage | 127 acre-ft |
| Surface Area | 12 acres |
| Year Completed | 1985 (41 years old) |
| NID ID | CA01293 |
Safety Information
No probable loss of human life and low economic/environmental losses expected.
Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?
Ownership
Juliana Mutual Water Company
Private
Nearby Dams
Upper Twin Lake
Napa, CA
Low Hazard 19 ftDick Week
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Significant Hazard 70 ftDeer Creek
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Low Hazard 40 ftLong Valley West No. 2
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Low Hazard 35 ftHardester North
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Significant Hazard 36 ftReservoir 2
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High Hazard 14 ftDavis
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Significant Hazard 42 ftTurkey Ranch
Napa, CA
High Hazard 35 ftFrequently Asked Questions
What is the hazard classification of Lower Twin Lake?
Lower Twin Lake is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.
Who owns and operates Lower Twin Lake?
Lower Twin Lake is owned by Juliana Mutual Water Company (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.
When was Lower Twin Lake built?
Lower Twin Lake was completed in 1985, making it 41 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 Lower Twin Lake?
Lower Twin Lake 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 Lower Twin Lake?
Lower Twin Lake has a dam height of 18 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 Lower Twin Lake last inspected?
Lower Twin Lake was last inspected on October 10, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.