Briones Reservoir Report

Last Updated: December 5, 2025

Briones Reservoir, located in El Sobrante, California, is a vital water resource managed by a public utility.


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Summary

With a primary purpose of flood risk reduction, this earth dam stands at a height of 273 feet and has been in operation since its completion in 1964. The reservoir boasts a storage capacity of 67,520 acre-feet and covers a surface area of 735 acres, drawing water from Bear Creek to serve the surrounding community.

Managed by the California Department of Water Resources, Briones Reservoir is subject to state regulation and inspection to ensure its safety and functionality. Despite being classified with a high hazard potential, the dam's condition assessment remains satisfactory as of September 2017. With a close eye on safety measures, the reservoir's emergency action plan is regularly updated to meet guidelines and address any potential risks or emergencies that may arise.

For water resource and climate enthusiasts, Briones Reservoir serves as a critical infrastructure piece in managing flood risks and providing water supply to the region. With its impressive height and storage capacity, this earth dam underscores the importance of proper regulation, inspection, and emergency preparedness in safeguarding our water resources and communities against potential hazards.

Year Completed

1964

Dam Length

2100

Dam Height

273

River Or Stream

Bear Creek

Primary Dam Type

Earth

Surface Area

735

Hydraulic Height

261.2

Drainage Area

8.6

Nid Storage

67520

Hazard Potential

High

Nid Height

273
       
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.