Menno Dam Reservoir Report

Last Updated: December 13, 2025

Menno Dam, also known as George S.


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Summary

Mickelson Dam, is a state-owned structure located in South Dakota. Completed in 1935, this earth dam stands at a height of 53 feet and spans a length of 660 feet along the James River tributary. With a normal storage capacity of 700 acre-feet and a maximum storage of 2050 acre-feet, Menno Dam plays a crucial role in managing and regulating water resources in the region.

The dam features an uncontrolled spillway with a width of 221 feet and vertical lift outlet gates. Despite its fair condition assessment as of the last inspection in October 2020, Menno Dam is classified as having a high hazard potential due to its location and the surrounding area's vulnerability to flooding. The risk assessment for the dam is moderate, reflecting the need for ongoing monitoring and maintenance to ensure its structural integrity and continued effectiveness in water resource management.

As a key piece of infrastructure in Hutchinson County, Menno Dam serves as a vital component of the local water management system. With its historical significance as a Works Progress Administration (WPA) project and its ongoing role in regulating water flow and storage, Menno Dam stands as a testament to the importance of sustainable water resource management in the face of changing climate conditions.

Year Completed

1935

Dam Length

660

Dam Height

53

River Or Stream

JAMES RIVER TRIBUTARY

Primary Dam Type

Earth

Hydraulic Height

53

Drainage Area

13

Nid Storage

2050

Outlet Gates

Vertical Lift

Hazard Potential

High

Foundations

Soil

Nid Height

53
       
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.