Beardsley Lake Reservoir Report

Last Updated: December 5, 2025

Beardsley Lake is a reservoir located in the Sierra Nevada Mountains in California.


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Summary

The lake was created in 1923 with the construction of Beardsley Dam, which was built for hydroelectric power generation. The lake is fed by the Middle Fork Stanislaus River and is used as a storage facility for water that is released to generate electricity. The area also receives snowpack that melts and flows into the lake. The lake provides water for agricultural uses such as irrigation and recreation activities such as fishing, boating, and camping. The lake has a surface area of 600 acres and a maximum depth of 240 feet. Overall, Beardsley Lake plays an important role in providing water resources and recreational opportunities for the surrounding communities.

Reservoir Details

Storage 24hr Change -0.82%
Percent of Normal 200%
Minimum 19,432.0 acre-ft
2007-12-01
Maximum 97,813.0 acre-ft
2017-07-18
Average 45,502 acre-ft
Dam_Height 278
Hydraulic_Height 276
Drainage_Area 310
Year_Completed 1957
Nid_Storage 97800
Hazard_Potential High
Structural_Height 284
Primary_Dam_Type Earth
River_Or_Stream Middle Fork Stanislaus River
Foundations Rock
Surface_Area 720
Outlet_Gates Tainter (radial) - 4
Dam_Length 1000
Nid_Height 284
       
Seasonal Comparison
Storage Levels
Pool Elevation Levels
Top Conserv Storage Levels
Inflow Levels

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.