Eau Galle Reservoir Report

Last Updated: December 25, 2025

Eau Galle, located in Dunn, Wisconsin, is a hydroelectric dam with a primary purpose of generating electricity and providing recreational opportunities.


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Summary

Built in 1913, this buttress dam stands at a height of 31 feet and has a length of 171 feet, with a storage capacity of 2070 acre-feet and a surface area of 350 acres. The dam is regulated by the Federal Energy Regulatory Commission and is not state-jurisdiction, but does require state permitting and enforcement.

With a low hazard potential and a very high risk assessment rating, Eau Galle is a vital water resource in the region. The dam features a controlled spillway with a width of 127 feet and a maximum discharge capacity of 20,000 cubic feet per second. Although the dam is not regularly inspected by state agencies, the Federal Energy Regulatory Commission oversees its operation and maintenance. The surrounding area offers opportunities for outdoor recreation, making Eau Galle a significant asset for both the local community and the environment.

Overall, Eau Galle serves as a key infrastructure for water resource management and electricity generation in Wisconsin. Despite its age, the dam continues to provide essential services and poses minimal risks to the surrounding area. With proper maintenance and oversight, Eau Galle will remain a valuable asset for years to come, supporting both the local economy and the preservation of natural habitats.

Year Completed

1913

Dam Length

171

Dam Height

31

River Or Stream

Eau Galle

Primary Dam Type

Buttress

Surface Area

350

Drainage Area

173

Nid Storage

2070

Outlet Gates

Bascule - 1

Hazard Potential

Low

Foundations

Rock

Nid Height

31
       
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.