Marion Reservoir Report

Last Updated: December 6, 2025

Marion, also known as Marion Millpond, is a gravity dam located in Waupaca, Wisconsin, along the North Branch Pigeon river.


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Summary

Built in 1880, this dam serves primarily for recreational purposes, offering hydroelectric power and recreation opportunities. With a structural height of 17 feet and a length of 114 feet, Marion has a storage capacity of 900 acre-feet and a surface area of 108 acres.

Managed by the local government and regulated by the Wisconsin Department of Natural Resources (WIDNR), Marion has a high hazard potential and is classified as very high risk. Despite its age, the dam is in satisfactory condition and undergoes regular inspections, with the last assessment conducted in March 2019. The surrounding area is at risk of inundation, prompting the need for emergency action plans to ensure public safety in case of a dam failure.

With a controlled spillway type and a maximum discharge capacity of 680 cubic feet per second, Marion remains a key water resource for the region. Its historical significance, combined with its vital role in water management and recreation, highlights the importance of continued maintenance and risk management measures to protect the community and the environment.

Years Modified

1906 - Other, 1995 - Other

Year Completed

1880

Dam Length

114

Dam Height

17

River Or Stream

NORTH BRANCH PIGEON

Primary Dam Type

Gravity

Surface Area

108

Hydraulic Height

16

Drainage Area

30

Nid Storage

900

Structural Height

17

Hazard Potential

High

Nid Height

17
       
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.