Middle Appleton Reservoir Report

Last Updated: December 6, 2025

Middle Appleton is a privately owned hydroelectric dam located on the Fox River in Appleton, Wisconsin.


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Summary

Built in 1930, this gravity dam stands at a height of 11 feet and has a hydraulic height of 10.5 feet. With a storage capacity of 195 acre-feet and a surface area of 36 acres, Middle Appleton plays a crucial role in generating hydroelectric power for the region.

Managed by the Federal Energy Regulatory Commission, Middle Appleton has a controlled spillway with a width of 300 feet and 16 Tainter (radial) outlet gates. Despite its low hazard potential, the dam is considered to have a very high risk level due to various factors. While the condition assessment is not available, the dam undergoes inspections every 3 years, with the last one conducted in August 2018. Emergency action plans are in place, with the last revision made in December 2019.

Water resource and climate enthusiasts will be intrigued by Middle Appleton's role in harnessing hydropower along the Fox River. Its historical significance, engineering design, and risk management measures provide valuable insights into the intersection of water infrastructure and environmental stewardship in the region. The dam's location in Outagamie County, Wisconsin, underlines its importance in maintaining water resources while balancing energy needs and environmental protection.

Year Completed

1930

Dam Length

372

Dam Height

11

River Or Stream

Fox River

Primary Dam Type

Gravity

Surface Area

36

Hydraulic Height

10.5

Drainage Area

6098

Nid Storage

195

Outlet Gates

Tainter (radial) - 16

Hazard Potential

Low

Foundations

Rock, Soil

Nid Height

11
       
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.