San Joaquin Reservoir Reservoir Report

Last Updated: December 5, 2025

San Joaquin Reservoir, located in Newport Beach, California, is a vital water supply resource managed by a public utility.


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Summary

The reservoir, completed in 1966, stands at a height of 224 feet and has a storage capacity of 3036 acre-feet. Situated on Tr Bonita Creek, it serves the primary purpose of providing water to the surrounding area, with a drainage area of 0.35 square miles.

With a surface area of 50 acres, San Joaquin Reservoir is regulated and inspected by the California Department of Water Resources for safety and compliance. Despite its high hazard potential, the dam is currently rated as satisfactory in condition, last assessed in September 2017. The Emergency Action Plan (EAP) for the reservoir was last revised in February 2021, ensuring preparedness and response in case of emergencies.

Managed by the Los Angeles District of the US Army Corps of Engineers, San Joaquin Reservoir plays a crucial role in water resource management in Orange County. Its strategic location and functional design make it a key component in the region's water supply infrastructure, contributing to the sustainability and resilience of the local water system.

Year Completed

1966

Dam Length

873

Dam Height

224

River Or Stream

Tr Bonita Creek

Primary Dam Type

Earth

Surface Area

50

Hydraulic Height

218.5

Drainage Area

0.35

Nid Storage

3036

Hazard Potential

High

Nid Height

224
       
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.