Apple River Reservoir Report

Last Updated: December 6, 2025

Apple River is a captivating hydroelectric dam located in St.


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Summary

Croix, Wisconsin, with a rich history dating back to its completion in 1954. Managed by the Federal Energy Regulatory Commission, this masonry dam stands at an impressive height of 47 feet and boasts a storage capacity of 668 acre-feet. With a primary purpose of hydroelectric power generation, Apple River also offers recreational opportunities for enthusiasts to enjoy.

This picturesque structure spans the Apple River, with a drainage area of 555 square miles and a maximum discharge of 9000 cubic feet per second. The dam features a controlled spillway with a width of 35 feet and is equipped with slide and tainter gates for efficient water flow management. Despite its high hazard potential, Apple River is regularly inspected to ensure its structural integrity and safety compliance.

With its unique design and significant role in power generation and water management, Apple River stands as a testament to sustainable resource utilization. As a popular destination for both energy enthusiasts and outdoor adventurers, this dam continues to play a vital role in the local ecosystem and economy while showcasing the harmonious blend of technology and nature.

Year Completed

1954

Dam Height

47

River Or Stream

Apple River

Primary Dam Type

Masonry

Surface Area

52

Drainage Area

555

Nid Storage

668

Outlet Gates

Slide (sluice gate) - 1, Tainter (radial) - 1

Hazard Potential

High

Foundations

Rock

Nid Height

47
       
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.