Lake Valley Auxiliary

North Fork American River· Placer, California· Built 1889· Earth· 28 ft tall
Significant Hazard Hydroelectric Private

Key Takeaway

Lake Valley Auxiliary is classified as significant hazard in California. It was completed in 1889 and is 137 years old. Its primary use is hydroelectric. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 28 ft (taller than 27.2% in CA)
Dam Length525 ft
Dam TypeEarth
Max Storage8.0K acre-ft
Normal Storage7.7K acre-ft
Surface Area298 acres
Drainage Area5 sq mi
Max Discharge5,200 cfs
Year Completed1889 (137 years old)
NID IDCA00361

Safety Information

Significant Hazard

No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes
Last Inspection: June 6, 2022
State Regulated: Yes
Regulatory Agency: DWR, Safety of Dams

Ownership

Pacific Gas and Electric Company

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Lake Valley Auxiliary?

Lake Valley Auxiliary is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Lake Valley Auxiliary?

Lake Valley Auxiliary is owned by Pacific Gas and Electric Company (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Lake Valley Auxiliary built?

Lake Valley Auxiliary was completed in 1889, making it 137 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 Valley Auxiliary?

Lake Valley Auxiliary serves the following purposes: Hydroelectric. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Lake Valley Auxiliary?

Lake Valley Auxiliary has a dam height of 28 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 Valley Auxiliary last inspected?

Lake Valley Auxiliary was last inspected on June 6, 2022. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.