Farmington Dam Reservoir Report

Last Updated: December 5, 2025

Farmington Dam in San Joaquin, California, stands as a crucial Federal structure managed by the US Army Corps of Engineers for flood risk reduction, hydroelectric power generation, irrigation, and water supply.


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Summary

Completed in 1951, this earth dam with stone core spans 7,800 feet in length and stands 58 feet tall, holding a maximum storage capacity of 119,314 acre-feet. Despite its high hazard potential, the dam is well-equipped with an uncontrolled spillway and emergency action plan to mitigate risks associated with extreme weather events such as heavy rainfall, snow melting, and earthquakes that could potentially lead to downstream flooding of communities like Farmington and Stockton.

USACE's risk management efforts at Farmington Dam include regular inspections, instrument monitoring, and collaboration with local emergency managers to update emergency action plans and conduct drills. By incorporating weather forecasts and adjusting dam releases accordingly, USACE aims to minimize risks to downstream communities. In the event of a catastrophic scenario like an extreme earthquake or uncontrolled water surge, the emergency action plan is designed to lower the risk of life loss by providing timely warnings to residents. While such events are considered unlikely, USACE's proactive measures help ensure the safety and security of the surrounding area.

Year Completed

1951

Dam Length

7800

Dam Height

58

River Or Stream

ROCK AND LITTLEJOHN CREEKS

Primary Dam Type

Earth

Surface Area

4100

Hydraulic Height

53

Drainage Area

212

Nid Storage

52000

Structural Height

58

Hazard Potential

High

Nid Height

58
       
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.