San Justo Reservoir Report

Last Updated: December 5, 2025

San Justo is a federal-owned irrigation dam located in Pacines, California, along the San Benito River.


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Summary

Built in 1987, this Earth-type dam stands at a height of 150.9 feet and serves the primary purpose of irrigation, with a storage capacity of 11,693 acre-feet. Managed by the Bureau of Reclamation, San Justo plays a crucial role in water resource management in the region, providing water for agricultural activities and supporting the local ecosystem.

With a high hazard potential and moderate risk assessment, San Justo has a spillway width of 508 feet and is equipped with uncontrolled spillways. The dam is regularly inspected by the Bureau of Reclamation to ensure its structural integrity and safety. Despite its age, the condition assessment of San Justo is currently listed as "Not Available", highlighting the need for ongoing monitoring and maintenance to mitigate any potential risks associated with the dam.

San Justo's presence along the San Benito River contributes to the water security and climate resilience of the surrounding area. As a vital infrastructure for irrigation, this dam underscores the importance of sustainable water management practices in the face of changing climate conditions. Enthusiasts of water resources and climate will find San Justo to be a fascinating example of how human-made structures can both harness and protect precious water resources in a dynamic environment.

Year Completed

1987

Dam Length

1115

Dam Height

150.9

River Or Stream

SAN BENITO RIVER OS

Primary Dam Type

Earth

Surface Area

208

Hydraulic Height

126

Drainage Area

1

Nid Storage

11693

Structural Height

151

Hazard Potential

High

Foundations

Rock

Nid Height

151
       
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.