Lake Eleanor Reservoir Report

Last Updated: December 5, 2025

Lake Eleanor is a reservoir located in Tuolumne County, California.


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Summary

The lake was created in the early 1900s as a part of the Hetch Hetchy water system development. It is managed by the San Francisco Public Utilities Commission and is used to supply water to the Bay Area. The hydrology of the lake is unique as it is fed by the Tuolumne River and receives water from the Hetch Hetchy Reservoir through a tunnel system. The snowpack from the Sierra Nevada Mountains also contributes to the lake's water supply. The lake is not used for agricultural purposes but is popular for recreational activities such as camping, fishing, and hiking. It is a part of the Stanislaus National Forest and is known for its scenic beauty.

Reservoir Details

Storage 24hr Change -0.07%
Percent of Normal 167%
Minimum 7,341.0 acre-ft
2020-12-31
Maximum 27,452.0 acre-ft
2022-12-31
Average 16,090 acre-ft
Dam_Height 61
Hydraulic_Height 61
Drainage_Area 80.4
Year_Completed 1918
Nid_Storage 28600
River_Or_Stream Eleanor Creek
Surface_Area 953
Hazard_Potential High
Dam_Length 1260
Primary_Dam_Type Multi-Arch
Nid_Height 61
       
Seasonal Comparison
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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.