Stony Gorge Reservoir Report

Last Updated: December 12, 2025

Stony Gorge, located in Glenn County, California, is a Federal-owned structure managed by the Bureau of Reclamation.


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Summary

Completed in 1928, this buttress dam serves as a vital water supply source for the region, with a storage capacity of 58,500 acre-feet and a normal storage level of 50,380 acre-feet. The dam stands at 151 feet in height and has a structural height of 151 feet, providing essential water resources for the surrounding area.

With a hazard potential categorized as high, Stony Gorge underwent modifications in 1985 for hydraulic and structural improvements, as well as seismic upgrades in 2009. The dam has a risk assessment rating of moderate (3), indicating the importance of ongoing risk management measures. Despite its age, the condition assessment of Stony Gorge is currently listed as not available, emphasizing the need for regular inspections and maintenance to ensure its continued function and safety.

In the event of an emergency, the Emergency Action Plan (EAP) for Stony Gorge was last revised in 2016, with an annual inspection frequency to monitor its safety. With its critical role in water supply and risk management, Stony Gorge stands as a key infrastructure for water resource and climate enthusiasts to monitor and support for the sustainable management of California's water systems.

Years Modified

1985 - Hydraulic, 1985 - Structural, 2009 - Seismic

Year Completed

1928

Dam Length

868

Dam Height

119

River Or Stream

STONY CREEK

Primary Dam Type

Buttress

Surface Area

1280

Hydraulic Height

131

Drainage Area

197

Nid Storage

58500

Structural Height

151

Hazard Potential

High

Nid Height

151
       
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.