Owens Dam Reservoir Report

Last Updated: December 5, 2025

Owens Dam, located in Mariposa, California, is a federally-owned structure managed by the US Army Corps of Engineers.


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Summary

Completed in 1949, this earth dam stands at a height of 72 feet and serves primarily for flood risk reduction and hydroelectric purposes along Owens Creek. With a maximum storage capacity of 6,064 acre-feet and normal storage of 4,138 acre-feet, the dam covers a surface area of 175 acres and has a drainage area of 26 square miles.

This high-hazard potential dam features an uncontrolled spillway, with a spillway width of 75 feet, and has a history of periodic inspections to ensure its structural integrity. The USACE actively manages dam-related flood risks by monitoring its condition, conducting maintenance and repairs as needed, and working closely with local emergency managers to develop emergency action plans and evacuation procedures. Despite the risks associated with flood events and dam releases, the USACE is dedicated to mitigating these risks and ensuring the safety of downstream communities. Additional details specific to the risk management measures for Owens Dam will be provided in the future to enhance public awareness and preparedness.

Year Completed

1949

Dam Length

790

Dam Height

72

River Or Stream

OWENS CREEK

Primary Dam Type

Earth

Surface Area

175

Hydraulic Height

70

Drainage Area

26

Nid Storage

3600

Structural Height

75

Hazard Potential

High

Nid Height

75
       
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.