Grizzly Forebay Reservoir Report

Last Updated: December 5, 2025

Grizzly Forebay in Pulga, California is a privately owned hydroelectric dam on Grizzly Creek, completed in 1928.


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Summary

With a dam height of 98 feet and a storage capacity of 1112 acre-feet, this concrete structure serves as a key component in the region's water resource management. The dam's spillway, with a width of 100 feet, is uncontrolled, and its maximum discharge capacity is 9200 cubic feet per second.

Maintained and regulated by the Federal Energy Regulatory Commission, Grizzly Forebay is rated with a high hazard potential due to its structural characteristics and location. Despite its age, the dam's risk assessment indicates a moderate level of risk, suggesting that it has been well-maintained and managed over the years. With its strategic location and importance for hydroelectric power generation, Grizzly Forebay stands as a testament to sustainable water resource utilization in California.

Enthusiasts of water resources and climate will find Grizzly Forebay to be a fascinating example of early 20th-century engineering and its continued relevance in the modern era. Its role in providing renewable energy and managing water resources in the region highlights the importance of sustainable infrastructure for addressing current and future climate challenges. As a regulated and inspected structure, Grizzly Forebay exemplifies the collaboration between private ownership, state agencies, and federal oversight to ensure the safety and efficiency of water management systems in California.

Year Completed

1928

Dam Length

520

Dam Height

98

River Or Stream

Grizzly Creek

Primary Dam Type

Concrete

Surface Area

38

Hydraulic Height

82

Drainage Area

14.6

Nid Storage

1112

Structural Height

87

Hazard Potential

High

Foundations

Rock

Nid Height

98
       
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.