Combined Locks Reservoir Report

Last Updated: December 6, 2025

Combined Locks in Kaukauna, Wisconsin is a hydroelectric dam on the Fox River, serving primarily for flood risk reduction and hydroelectric power generation.


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Summary

This gravity-type dam stands at a height of 23.1 feet and has a hydraulic height of 22 feet, with a structural height of 28 feet. Completed in 1912, the dam has a storage capacity of 1700 acre-feet, with a normal storage level of 1600 acre-feet and a maximum discharge rate of 20800 cubic feet per second. With a significant hazard potential, the dam is regulated by the Federal Energy Regulatory Commission and does not fall under state jurisdiction.

The dam features a multi-arch core with a concrete and gravity structure resting on rock foundation. It spans a length of 653 feet and has a spillway width of 288 feet, operating with uncontrolled spillway type. The outlet gates consist of seven Tainter (radial) gates, facilitating water flow management. While the condition assessment is not available, the dam is subject to moderate risk with a risk assessment rating of 3. Emergency action plans are in place, last revised in January 2021, to ensure preparedness in case of unforeseen events. With its historical significance and operational relevance in water resource management, Combined Locks remains a key infrastructure for sustaining the surrounding ecosystem and local community.

Year Completed

1912

Dam Length

653

Dam Height

23.1

River Or Stream

Fox River

Primary Dam Type

Gravity

Surface Area

180

Hydraulic Height

22

Drainage Area

6000

Nid Storage

1700

Structural Height

28

Outlet Gates

Tainter (radial) - 7

Hazard Potential

Significant

Foundations

Rock

Nid Height

28
       
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.