Vermilion Valley Reservoir Report

Last Updated: December 5, 2025

Vermilion Valley, also known as Edison Lake, is a private hydroelectric facility located in Fresno, California, along the picturesque Mono Creek.


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Summary

Built by Bechtel and completed in 1954, this earth dam stands at 165 feet tall and stretches over 4,200 feet long, with a storage capacity of 140,000 acre-feet. With a normal storage level of 125,035 acre-feet and a maximum discharge capacity of 18,800 cubic feet per second, this dam plays a crucial role in water resource management and power generation in the region.

Managed by the Federal Energy Regulatory Commission, Vermilion Valley's spillway system is of the controlled type, with one Tainter radial gate for water release. The dam's hazard potential is classified as high, with a risk assessment rating of very high. Despite its age, the dam's condition assessment is currently not available, and its Emergency Action Plan (EAP) status is also pending updates. As a key player in California's water infrastructure, Vermilion Valley serves as a vital asset for both water resource and climate enthusiasts interested in the sustainable management of our natural resources.

With its strategic location in the Sacramento District and its crucial role in water storage and power generation, Vermilion Valley stands as a testament to human ingenuity in harnessing the power of nature for the greater good. As a private facility under state regulation, this dam represents the intersection of technology, environmental stewardship, and public safety. For enthusiasts passionate about water resources and climate resilience, Vermilion Valley offers a fascinating case study in the complexities of managing and maintaining vital infrastructure in the face of changing climatic conditions and regulatory challenges.

Year Completed

1954

Dam Length

4234

Dam Height

165

River Or Stream

Mono Creek

Primary Dam Type

Earth

Surface Area

1910

Drainage Area

88.3

Nid Storage

140000

Outlet Gates

Tainter (radial) - 1

Hazard Potential

High

Foundations

Soil

Nid Height

165
       
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.