Tulloch Reservoir Report

Last Updated: December 5, 2025

Tulloch is a reservoir located in the Sierra Nevada Mountains of California.


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Summary

It was created in 1955 with the construction of the Tulloch Dam on the Stanislaus River. The reservoir has a total capacity of 83,000 acre-feet and is used to provide irrigation water for agriculture and to generate hydroelectric power. The hydrology of the area is heavily impacted by the snowpack in the surrounding mountains, which provides a significant amount of the surface flow into the reservoir during the spring and summer months. The lake is a popular destination for recreational activities such as boating, fishing, and camping. The surrounding area is also home to many vineyards and orchards that rely on the irrigation water provided by the reservoir.

Reservoir Details

Storage 24hr Change -1.22%
Percent of Normal 125%
Minimum 31,204.0 acre-ft
2023-12-12
Maximum 66,906.0 acre-ft
2005-08-09
Average 51,508 acre-ft
Dam_Height 205
Hydraulic_Height 165
Drainage_Area 980
Year_Completed 1958
Nid_Storage 68400
Structural_Height 200
Foundations Rock
Surface_Area 1260
Outlet_Gates Tainter (radial) - 7
River_Or_Stream Stanislaus River
Dam_Length 1914
Hazard_Potential High
Primary_Dam_Type Concrete
Nid_Height 205
       
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.