Turtle-Flambeau Detached Dike 1 Reservoir Report

Last Updated: December 5, 2025

Turtle-Flambeau Detached Dike 1, located in Iron, Wisconsin, is a public utility structure managed by the Federal Energy Regulatory Commission.


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Summary

Built in 1926, this earth dam stands at a height of 12 feet and has a storage capacity of 239,000 acre-feet. The dam plays a crucial role in flood control and water management in the region, with a high hazard potential due to its significant storage capacity.

Associated with eight other structures, Turtle-Flambeau Detached Dike 1 has not been inspected since September 2019, with a high risk potential and no condition assessment available. While it meets regulatory guidelines, there is no Emergency Action Plan (EAP) prepared, raising concerns about emergency preparedness. With a history of serving the community for nearly a century, ongoing monitoring and maintenance are essential to ensure the safety and integrity of this vital water resource infrastructure.

As climate change continues to impact water resources and infrastructure, the importance of regular inspections, risk assessments, and emergency preparedness for structures like Turtle-Flambeau Detached Dike 1 cannot be overstated. With its strategic location and significant storage capacity, this dam plays a crucial role in protecting downstream communities and ecosystems from potential flooding events. Ongoing collaboration between federal and state agencies is essential to ensure the continued safety and effectiveness of this key water management structure.

Year Completed

1926

Dam Height

12

Primary Dam Type

Earth

Surface Area

13798

Nid Storage

239000

Hazard Potential

High

Foundations

Rock, Soil

Nid Height

12
       
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.