Winnibigoshish Dam - Dike 1 Reservoir Report

Last Updated: December 5, 2025

Winnibigoshish Dam - Dike 1, located in Cass County, Minnesota, was completed in 1884 with a primary purpose of water supply.


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Summary

The dam, made of earth and stone materials, stands at a height of 5 feet and a length of 50 feet, with a storage capacity of 550,000 acre-feet. Although the dam no longer serves its original function of preventing breakout flows into Portage Lake, it still plays a significant role in flood risk reduction, navigation, recreation, and wildlife conservation in the area.

Managed by the US Army Corps of Engineers, Winnibigoshish Dam undergoes regular inspections and maintenance to ensure its structural integrity and operational effectiveness. The dam poses a significant hazard potential, prompting the implementation of risk management measures that involve monitoring, prioritizing activities, and coordinating with local emergency managers to develop and update emergency action plans. Despite being effectively replaced by Highway 2, the dam continues to contribute to the overall water resource management and environmental preservation efforts in the region.

In light of the dam's historical significance and ongoing relevance, it serves as a critical component of the water infrastructure in the area and showcases the continuous efforts of the US Army Corps of Engineers in safeguarding water resources, mitigating risks, and ensuring public safety in the face of potential dam-related emergencies.

Year Completed

1884

Dam Length

50

Dam Height

5

River Or Stream

MISSISSIPPI RIVER

Primary Dam Type

Earth

Surface Area

68000

Hydraulic Height

5

Drainage Area

1442

Nid Storage

550000

Structural Height

5

Hazard Potential

Significant

Foundations

Soil

Nid Height

5
       
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.