Wishon Forebay Reservoir Report

Last Updated: December 5, 2025

Wishon Forebay, also known as Corrine Lake, is a privately-owned reservoir located in Friant, California.


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Summary

Built in 1896, this hydroelectric facility serves multiple purposes including hydroelectric power generation and recreation. The earth dam stands at a height of 15 feet and has a spillway width of 62 feet, with a maximum storage capacity of 69 acre-feet and a surface area of 7 acres. The reservoir is situated on the North Fork Willow Creek, part of the Sacramento District, and is regulated by the Federal Energy Regulatory Commission.

The dam at Wishon Forebay has a low hazard potential and a moderate risk assessment rating. While the condition assessment is not available, the dam is inspected regularly by both state and federal agencies, with the last inspection taking place in September 2017. Emergency action plans are in place, with the most recent update in October 2020, to ensure the safety and security of the surrounding area in case of a dam failure. With its historical significance and important role in water resource management and energy production, Wishon Forebay is a site of interest for water resource and climate enthusiasts alike.

Overall, Wishon Forebay is a vital component of California's water infrastructure, providing both renewable energy and recreational opportunities for the surrounding community. With its long-standing history and regulated status, the reservoir continues to play a significant role in water management and environmental conservation efforts in the region. For those interested in water resources and climate issues, Wishon Forebay offers a fascinating glimpse into the intersection of hydroelectric power generation, dam safety, and recreational use within the state of California.

Year Completed

1896

Dam Length

1572

Dam Height

15

River Or Stream

North Fork Willow Creek

Primary Dam Type

Earth

Surface Area

7

Hydraulic Height

12

Nid Storage

69

Structural Height

15

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

15
       
Seasonal Comparison

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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.