Potato Rapids Reservoir Report

Last Updated: December 5, 2025

Potato Rapids, located in Marinette, Wisconsin, along the Peshtigo River, is a gravity dam completed in 1920 primarily for hydroelectric purposes.


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Summary

With a height of 19 feet and a length of 1220 feet, the dam has a normal storage capacity of 2800 acre-feet and a maximum discharge of 21000 cubic feet per second. The controlled spillway, with a width of 158 feet, helps regulate water flow, ensuring efficient operation of the hydroelectric facility.

Managed by a public utility, Potato Rapids boasts a low hazard potential and a very high risk assessment rating of 1. Despite not being state-regulated, the dam falls under the jurisdiction of the Federal Energy Regulatory Commission for permitting, inspections, and enforcement. The facility also offers recreational opportunities in addition to its hydroelectric function, adding to its value as a water resource in the region.

Overall, Potato Rapids serves as a vital infrastructure for water resource management and renewable energy production in Wisconsin. With its historic significance and strategic location on the Peshtigo River, the dam plays a crucial role in the local community's water supply, recreation, and climate resilience efforts.

Year Completed

1920

Dam Length

1220

Dam Height

19

River Or Stream

Peshtigo River

Primary Dam Type

Gravity

Surface Area

350

Hydraulic Height

17

Drainage Area

1030

Nid Storage

2800

Structural Height

20

Outlet Gates

Tainter (radial) - 7

Hazard Potential

Low

Foundations

Rock, Soil

Nid Height

20
       
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.