Pyramid Reservoir Report

Last Updated: December 5, 2025

Pyramid Dam, located in Piru, California, is a state-regulated structure built in 1974 by the California Department of Water Resources (DWR) for water supply purposes.


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Summary

Standing at a height of 400 feet and with a hydraulic height of 380 feet, the dam plays a crucial role in flood risk reduction, hydroelectric power generation, recreation, and water supply for the region. With a storage capacity of 171,000 acre-feet and a surface area of 1,290 acres, Pyramid Dam is a key component of the water resource infrastructure in Los Angeles County.

Managed by the Federal Energy Regulatory Commission (FERC), Pyramid Dam has a controlled spillway with a width of 40 feet and is equipped with a Tainter radial gate for water release. The dam has a high hazard potential and is subject to regular inspections and state enforcement to ensure its structural integrity and safety. Despite its importance in water management, the condition assessment of Pyramid Dam is currently marked as not available, highlighting the need for ongoing monitoring and maintenance to mitigate risks associated with its operation.

As a vital water supply source for the region, Pyramid Dam's risk assessment is classified as very high, emphasizing the critical role it plays in managing water resources in the area. With its strategic location on Piru Creek and its significant storage capacity, Pyramid Dam serves as a cornerstone for ensuring water security, flood protection, and sustainable development in Los Angeles County.

Year Completed

1974

Dam Length

1090

Dam Height

400

River Or Stream

Piru Creek

Primary Dam Type

Earth

Surface Area

1290

Hydraulic Height

380

Drainage Area

432

Nid Storage

171000

Structural Height

422

Outlet Gates

Tainter (radial) - 1

Hazard Potential

High

Foundations

Rock

Nid Height

422
       
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.