Lower Peak Lake Auxiliary

South Yuba River - Tr· Placer, California· Built 1860· Earth· 7 ft tall
High Hazard Hydroelectric Private

Key Takeaway

Lower Peak Lake Auxiliary is classified as high hazard in California. It was completed in 1860 and is 166 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 7 ft (taller than 0.1% in CA)
Dam Length410 ft
Dam TypeEarth
Max Storage484 acre-ft
Normal Storage480 acre-ft
Surface Area33 acres
Drainage Area1 sq mi
Max Discharge312 cfs
Year Completed1860 (166 years old)
NID IDCA00365

Safety Information

High Hazard

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?

Emergency Action Plan: Yes
Last Inspection: June 28, 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 Lower Peak Lake Auxiliary?

Lower Peak Lake Auxiliary 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 Lower Peak Lake Auxiliary?

Lower Peak Lake 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 Lower Peak Lake Auxiliary built?

Lower Peak Lake Auxiliary was completed in 1860, making it 166 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 Peak Lake Auxiliary?

Lower Peak Lake 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 Lower Peak Lake Auxiliary?

Lower Peak Lake Auxiliary has a dam height of 7 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 Peak Lake Auxiliary last inspected?

Lower Peak Lake Auxiliary was last inspected on June 28, 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.