Lake Valley Auxiliary Reservoir Report

Last Updated: December 5, 2025

Lake Valley Auxiliary is a private hydroelectric dam located in Placer, California, near the North Fork American River.


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Summary

Built in 1889, this Earth-type dam stands at a height of 28 feet and has a maximum storage capacity of 7,964 acre-feet. With a surface area of 298 acres and a drainage area of 4.5 square miles, the dam plays a crucial role in regulating water flow and generating hydroelectric power for the region.

Managed by the Federal Energy Regulatory Commission, Lake Valley Auxiliary has a significant hazard potential and is subject to regular state inspections and enforcement. While the dam's condition assessment is not currently available, its emergency action plan was last revised in December 2020, indicating ongoing efforts to ensure safety and preparedness in case of emergencies. The dam's spillway, with a width of 100 feet, helps control water levels during periods of high discharge, contributing to effective water resource management in the area.

Overall, Lake Valley Auxiliary serves as a key infrastructure for water resource and climate enthusiasts, providing insights into the intersection of hydroelectric power generation, dam safety regulations, and emergency response planning. Located in a picturesque setting near Washington, California, this historic dam continues to play a vital role in water management and renewable energy production in the region, highlighting the importance of sustainable practices for a resilient future.

Year Completed

1889

Dam Length

525

Dam Height

28

River Or Stream

North Fork American River

Primary Dam Type

Earth

Surface Area

298

Hydraulic Height

18

Drainage Area

4.5

Nid Storage

7964

Structural Height

25

Hazard Potential

Significant

Nid Height

28
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.