Junction Reservoir Report

Last Updated: December 4, 2025

Junction, a hydroelectric dam located in Coloma, California, is a significant structure managed by a public utility.


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Summary

Designed by Bechtel and completed in 1962, this concrete dam stands at a height of 168 feet with a hydraulic height of 150 feet, serving as a crucial component in the South Fork Silver Creek. With a storage capacity of 3000 acre-feet and a maximum discharge of 53,000 cubic feet per second, Junction plays a vital role in regulating water flow and generating hydroelectric power in the region.

Owned by a public utility and regulated by the Department of Water Resources, Safety of Dams, Junction is subject to state inspections, permitting, and enforcement to ensure its structural integrity and operational safety. With a spillway type classified as "Uncontrolled", the dam has a significant hazard potential and is considered to have a moderate risk level. Emergency action plans are in place, with the last revision conducted in February 2021, indicating a proactive approach to managing potential risks associated with the dam.

The location of Junction in El Dorado County, California, highlights its importance in water resource management and climate adaptation efforts. As a key player in the Federal Energy Regulatory Commission's jurisdiction, Junction serves as a critical infrastructure for both water supply and hydroelectric power generation, contributing to the sustainable development of the region. With its historical significance and ongoing maintenance efforts, Junction remains a crucial asset in California's water resource and climate resilience strategies.

Year Completed

1962

Dam Length

525

Dam Height

168

River Or Stream

South Fork Silver Creek

Primary Dam Type

Concrete

Surface Area

64

Hydraulic Height

150

Drainage Area

142

Nid Storage

3000

Structural Height

168

Hazard Potential

Significant

Nid Height

168
       
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.