Lake Winnebago Dam Expansion Reservoir Report

Last Updated: December 7, 2025

The Lake Winnebago Dam Expansion project, not yet built, is a private initiative designed by Olsson Associates in Missouri.


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Summary

The dam, classified as an earth dam with buttress core type, stands at 63 feet high and has a storage capacity of 13,700 acre-feet. Located in Cass County, Missouri, the dam serves the City of Lake Winnebago and is regulated by the state, with required inspections and enforcement in place to ensure its safety.

With a hazard potential rated as high, the condition of the dam is currently not rated. Despite its high risk, the dam has not undergone a formal risk assessment or had an Emergency Action Plan (EAP) prepared. The project is situated within the Tulsa District of the US Army Corps of Engineers jurisdiction, with no federal agency involvement or funding reported. The dam's expansion is intended to enhance water resource management and flood control in the area, with a normal storage capacity of 6,760 acre-feet and a surface area of 416 acres.

Overall, the Lake Winnebago Dam Expansion project presents a significant opportunity for improving water resource infrastructure in Missouri. However, with its high hazard potential and lack of formal risk assessment and emergency preparedness measures, there is a need for careful monitoring and planning to ensure the safety and effectiveness of the proposed expansion. Climate and water resource enthusiasts will be keen to follow the progress of this private development as it unfolds in the coming years.

Dam Height

63

Surface Area

416

Drainage Area

14090

Nid Storage

13700

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

63
       
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.