Wishon Main Reservoir Report

Last Updated: December 5, 2025

Wishon Main is a privately owned hydroelectric dam located in Wishon Village, California, along the North Fork Kings River.


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Summary

Completed in 1958, this rockfill dam stands at a height of 260 feet and has a storage capacity of 133,600 acre-feet, with a normal storage level of 129,118 acre-feet. The dam's primary purpose is hydroelectric power generation, with a maximum discharge capacity of 52,200 cubic feet per second.

Managed by the Federal Energy Regulatory Commission, Wishon Main has a controlled spillway with a width of 330 feet and is equipped with six Tainter (radial) outlet gates. With a high hazard potential and a very high risk assessment rating, the dam is under state regulation and inspection to ensure its safety and compliance with dam safety guidelines. Despite its risk assessment, the condition assessment of Wishon Main is currently listed as "Not Available," indicating a need for further evaluation and monitoring of the dam's structural integrity.

Located in Fresno County, California, Wishon Main plays a crucial role in water resource management and energy production in the region. As a key component of the hydroelectric infrastructure, this dam serves as a vital resource for the surrounding community and contributes to the sustainable development of the local area. With its impressive height and storage capacity, Wishon Main stands as a testament to human ingenuity in harnessing the power of water for the benefit of society while also highlighting the importance of continuous monitoring and maintenance to ensure the safety and reliability of such critical infrastructure.

Year Completed

1958

Dam Length

3330

Dam Height

260

River Or Stream

North Fork Kings River

Primary Dam Type

Rockfill

Surface Area

1025

Hydraulic Height

260

Drainage Area

177

Nid Storage

133600

Structural Height

260

Outlet Gates

Tainter (radial) - 6

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

260
       
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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.