Lake Spaulding No. 2 Reservoir Report

Last Updated: December 5, 2025

Lake Spaulding No.


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Summary

2 is a captivating hydroelectric reservoir located in Nevada County, California, near the town of Washington. Built in 1916, this concrete gravity dam stands at a height of 42 feet and has a maximum storage capacity of 74,773 acre-feet. The dam stretches 309 feet in length and features a controlled spillway with a width of 271 feet, ensuring the safe release of water during peak flows.

Managed by a private owner, Lake Spaulding No. 2 is regulated by the California Department of Water Resources and undergoes regular inspections to ensure its structural integrity and safety. With a high hazard potential and very high risk assessment, this dam plays a crucial role in providing hydroelectric power to the region while also posing potential risks in the event of a failure. The reservoir covers a surface area of 698 acres and is fed by the South Yuba River, making it a vital resource for water supply and energy production in the area.

Despite its age, Lake Spaulding No. 2 continues to be a key component of California's water and energy infrastructure. With a strong emphasis on safety and regulatory compliance, this dam serves as a reminder of the delicate balance between harnessing natural resources for human benefit and mitigating the potential risks associated with large-scale water management projects. As climate and water resource enthusiasts, the dynamic nature of Lake Spaulding No. 2's operations and maintenance provides a fascinating insight into the intricate relationship between human development and environmental stewardship.

Year Completed

1916

Dam Length

309

Dam Height

42

River Or Stream

South Yuba River

Primary Dam Type

Concrete

Surface Area

698

Hydraulic Height

39.5

Nid Storage

74773

Structural Height

41

Outlet Gates

Tainter (radial) - 10

Hazard Potential

High

Nid Height

42
       
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.