Tulloch Reservoir Report

Last Updated: December 5, 2025

Tulloch, located in Knights Ferry, California, is a concrete dam on the Stanislaus River with a primary purpose of hydroelectric power generation.


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Summary

Completed in 1958, it stands at a height of 205 feet and has a hydraulic height of 165 feet, providing a maximum storage capacity of 68,400 acre-feet and a normal storage capacity of 67,000 acre-feet. The dam, designed by George E. Goodall Co., spans 1,914 feet in length and has a controlled spillway with a width of 280 feet, ensuring efficient water management during peak discharges.

Maintained by the Federal Energy Regulatory Commission, Tulloch is a state-regulated and inspected structure with a high hazard potential due to its location in a densely populated area. The dam's associated purposes include flood risk reduction and recreation, in addition to hydroelectric power generation. Despite its age, Tulloch's risk assessment remains very high, emphasizing the need for ongoing monitoring and maintenance to ensure the safety and reliability of this critical water resource infrastructure in Calaveras County. As a significant feature on the Stanislaus River, Tulloch plays a vital role in water resource management and climate resilience efforts in the region.

Year Completed

1958

Dam Length

1914

Dam Height

205

River Or Stream

Stanislaus River

Primary Dam Type

Concrete

Surface Area

1260

Hydraulic Height

165

Drainage Area

980

Nid Storage

68400

Structural Height

200

Outlet Gates

Tainter (radial) - 7

Hazard Potential

High

Foundations

Rock

Nid Height

205
       
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.