Neenah Reservoir Report

Last Updated: December 6, 2025

Neenah, a privately owned dam located in Winnebago, Wisconsin, plays a crucial role in flood risk reduction along the Fox River.


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Summary

Built in 1881, this gravity dam stands at a height of 15 feet and spans 650 feet, providing a storage capacity of 1,100,000 acre-feet. With a normal storage capacity of 700,000 acre-feet and a drainage area of 6,124 square miles, Neenah is essential in managing water levels and mitigating potential flooding in the region.

Despite its age, Neenah remains in satisfactory condition and is inspected regularly to ensure its structural integrity and operational effectiveness. With a high hazard potential and a very high risk assessment rating, it is vital that the dam continues to be properly maintained and managed. The dam's controlled spillway, with a maximum discharge capacity of 24,000 cubic feet per second, further enhances its flood risk reduction capabilities, safeguarding the surrounding communities and infrastructure from potential water-related disasters.

Neenah not only serves as a critical infrastructure for flood control but also offers recreational opportunities for the local community. As one of the key structures managed by the Wisconsin Department of Natural Resources (WIDNR), Neenah stands as a testament to effective water resource management and climate resilience efforts in the region, highlighting the importance of sustainable practices in safeguarding our water resources for future generations.

Years Modified

1922 - Other

Year Completed

1881

Dam Length

650

Dam Height

15

River Or Stream

FOX R

Primary Dam Type

Gravity

Surface Area

137708

Hydraulic Height

9

Drainage Area

6124

Nid Storage

1100000

Structural Height

15

Hazard Potential

High

Nid Height

15
       
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.