Dunkirk Reservoir Report

Last Updated: December 6, 2025

Dunkirk, located in Dane County, Wisconsin, is a privately owned hydroelectric dam on the Yahara River.


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Summary

Completed in 1915, this gravity dam stands at a height of 20 feet and has a structural height of 22.4 feet. With a normal storage capacity of 270 acre-feet and a maximum discharge of 4,626 cubic feet per second, Dunkirk serves not only as a source of hydroelectric power but also for recreational activities.

Managed by the Federal Energy Regulatory Commission, Dunkirk's spillway type is controlled, with a width of 55 feet. The dam features Tainter and vertical lift outlet gates, and has a low hazard potential. Although the condition assessment is not available, the risk assessment for Dunkirk is rated as very high, emphasizing the importance of effective risk management measures. Despite its age, Dunkirk continues to play a crucial role in the region's water resource management and climate adaptation efforts.

As water resource and climate enthusiasts, Dunkirk serves as a fascinating example of how historic infrastructure can be repurposed for modern needs while balancing environmental considerations. With its blend of hydroelectric power generation and recreational opportunities, Dunkirk stands as a testament to sustainable water resource management practices. As efforts continue to manage the risk associated with this aging structure, Dunkirk remains a symbol of innovation and resilience in the face of evolving climate challenges.

Year Completed

1915

Dam Length

800

Dam Height

20

River Or Stream

Yahara River

Primary Dam Type

Gravity

Surface Area

70

Hydraulic Height

11

Drainage Area

414

Nid Storage

270

Structural Height

22.4

Outlet Gates

Tainter (radial) - 1, Vertical Lift - 2

Hazard Potential

Low

Foundations

Soil

Nid Height

22
       
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.