Gunderson-Marmsoler Detention Reservoir Report

Last Updated: December 5, 2025

Gunderson-Marmsoler Detention, located in Winona, Minnesota, is a privately owned earth dam designed by the USDA NRCS for flood risk reduction.


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Summary

Completed in 1972, this structure stands at 34 feet tall and stretches 331 feet in length along the Big Trout Creek-TR. With a low hazard potential and satisfactory condition assessment, this detention facility has a storage capacity of 16.3 acre-feet and a drainage area of 0.5 square miles.

Maintained by the Minnesota Department of Natural Resources, this detention serves a critical role in mitigating flood risks in the region. With uncontrolled spillways and outlets, it is equipped to handle a maximum discharge of 160 cubic feet per second. The dam's risk assessment rates it as moderate, highlighting the importance of ongoing monitoring and risk management measures to ensure its effectiveness in protecting the surrounding areas from potential inundation events.

Owned by a private entity, Gunderson-Marmsoler Detention plays a vital role in the flood risk reduction efforts in the region. With its earth construction and buttress core type, this structure exemplifies the collaboration between private landowners and government agencies in safeguarding water resources and enhancing climate resilience. As climate change continues to impact water systems, facilities like Gunderson-Marmsoler Detention will be instrumental in adapting to and mitigating the challenges posed by a changing climate.

Year Completed

1972

Dam Length

331

Dam Height

29

River Or Stream

BIG TROUT CREEK-TR

Primary Dam Type

Earth

Drainage Area

0.5

Nid Storage

16.3

Structural Height

34

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

34
       
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.