Donnells Reservoir Report

Last Updated: December 5, 2025

Donnell Lake in California is a hydroelectric reservoir that was created in the 1950s.


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Summary

The lake is fed by the Middle Fork Stanislaus River, and its primary purpose is to provide water storage for hydropower generation. The surrounding area is also home to several creeks and streams that contribute to the area's hydrology. In terms of surface flow, Donnell Lake is a significant provider of water for the surrounding areas, particularly during the dry summer months. The area also receives a significant amount of snowpack during the winter, which also contributes to the region's hydrology. While the primary use of Donnell Lake is for hydropower generation, it also supports various agricultural and recreational activities. Farmers in the area use the water for irrigation, and the lake is a popular spot for boating and fishing.

Reservoir Details

Storage 24hr Change None%
Percent of Normal None%
Minimum 4.0 acre-ft
2023-10-02
Maximum 64,801.0 acre-ft
2006-07-13
Average 26,517 acre-ft
Nid_Height 317
Hydraulic_Height 310
Primary_Dam_Type Concrete
Drainage_Area 226
Year_Completed 1958
Dam_Height 317
Structural_Height 317
Foundations Rock
Surface_Area 418
Outlet_Gates Tainter (radial) - 5
Nid_Storage 65000
River_Or_Stream Middle Fork Stanislaus River
Dam_Length 750
Hazard_Potential High
       
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.