Potrero Reservoir Report

Last Updated: December 5, 2025

Potrero is a private dam located in Thousand Oaks, California, along the Triunfo Canyon Cr.


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Summary

Built in 1967, this gravity dam stands at a height of 40 feet and has a storage capacity of 1600 acre-feet. Its primary purpose is flood risk reduction, but it also serves as a water supply source for the region. The dam is under state regulation and inspection by the Department of Water Resources (DWR) for safety compliance.

With a hazard potential rated as high, Potrero has been deemed to be in satisfactory condition as of the last assessment in September 2017. Regular inspections are conducted, with the most recent one taking place in March 2020. In case of emergencies, an Emergency Action Plan (EAP) is in place, and the dam meets safety guidelines. Despite its age, Potrero continues to play a crucial role in managing flood risks and providing essential water supply to the surrounding area, showcasing the importance of infrastructure maintenance and monitoring in the face of climate challenges.

Year Completed

1967

Dam Length

730

Dam Height

40

River Or Stream

Triunfo Canyon Cr

Primary Dam Type

Gravity

Surface Area

95

Hydraulic Height

30

Drainage Area

28.9

Nid Storage

1600

Hazard Potential

High

Nid Height

40
       
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.