San Gabriel Reservoir Report

Last Updated: December 5, 2025

San Gabriel Dam, located in Azusa, California, is a vital structure managed by the local government for flood risk reduction and hydroelectric purposes.


°F

°F

mph

Wind

%

Humidity

Summary

Completed in 1937, this earth dam stands at a height of 320 feet and has a maximum storage capacity of 45,832 acre-feet. With a drainage area of 203 square miles and a maximum discharge capacity of 297,000 cubic feet per second, the dam plays a crucial role in managing water resources in the region.

Owned by the Federal Energy Regulatory Commission (FERC) and regulated by the Safety of Dams division of the California Department of Water Resources, San Gabriel Dam is subject to regular inspections and enforcement to ensure its structural integrity and safety. The dam's high hazard potential underscores the importance of its maintenance and emergency preparedness. Despite its age, the risk assessment for San Gabriel Dam is moderate, indicating a need for ongoing risk management measures to safeguard the surrounding communities and water resources.

San Gabriel Dam's presence on the San Gabriel River not only helps in flood control but also contributes to the local hydroelectric power generation. With its strategic location and significant storage capacity, this dam is a key player in the water resource management and climate resilience efforts in Los Angeles County, making it an essential structure for water resource and climate enthusiasts to monitor and appreciate.

Year Completed

1937

Dam Length

1500

Dam Height

320

River Or Stream

San Gabriel River

Primary Dam Type

Earth

Hydraulic Height

292

Drainage Area

203

Nid Storage

45832

Structural Height

381

Hazard Potential

High

Foundations

Soil

Nid Height

381
       
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.