Castaic Reservoir Report

Last Updated: December 5, 2025

Castaic, located in Los Angeles County, California, is a state-regulated dam on Castaic Creek with a primary purpose of water supply.


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Summary

Completed in 1973, this earth-type dam stands at 340 feet in height and has a storage capacity of 323,700 acre-feet. The dam also serves multiple purposes including irrigation and recreation, making it a vital resource for the region.

Despite its significant storage capacity, Castaic Dam has a high hazard potential and a poor condition assessment as of August 2021. The dam's last inspection in October 2021 revealed the need for improvements to ensure its safety and functionality. With the dam being state-regulated and inspected regularly, efforts are likely being made to address any potential risks and enhance the dam's overall condition.

Castaic Dam plays a crucial role in water supply management for the area, and its importance cannot be understated. With ongoing assessments and potential risk management measures in place, the dam continues to be a key asset in maintaining water resources and ensuring the safety of surrounding communities in the face of changing climate conditions.

Year Completed

1973

Dam Length

5200

Dam Height

340

River Or Stream

Castaic Creek

Primary Dam Type

Earth

Surface Area

2235

Hydraulic Height

320

Drainage Area

153.7

Nid Storage

323700

Hazard Potential

High

Nid Height

340
       
Seasonal Comparison

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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.