Radigan Reservoir Report

Last Updated: December 5, 2025

Radigan is a gravity dam located on the Upper Tamarack River in Douglas, Wisconsin.


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Summary

Completed in 1938, the dam serves primarily for recreational purposes, providing a storage capacity of 420 acre-feet and a surface area of 150 acres. With a structural height of 12 feet and a hydraulic height of 7 feet, Radigan also has a spillway width that allows for controlled discharge of up to 3595 cubic feet per second.

Despite its historical significance, Radigan has been classified as having a high hazard potential due to its poor condition assessment. The dam underwent modifications in 1964 and is currently regulated, permitted, inspected, and enforced by the Wisconsin Department of Natural Resources. With a risk assessment rating of "Very High (1)", there is a pressing need for risk management measures to be implemented to ensure the safety and integrity of the structure for both water resource management and climate-related concerns.

Overall, Radigan presents both a valuable recreational resource and a significant engineering challenge in terms of maintenance and risk management. As water resource and climate enthusiasts, it is essential to recognize the importance of proactive measures in safeguarding dams like Radigan to mitigate potential hazards and ensure the sustainability of water infrastructure in the face of changing environmental conditions.

Years Modified

1964 - Other

Year Completed

1938

Dam Length

300

Dam Height

12

River Or Stream

Upper Tamarack River

Primary Dam Type

Gravity

Surface Area

150

Hydraulic Height

7

Drainage Area

41

Nid Storage

420

Structural Height

12

Hazard Potential

High

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.