Oconto Falls Lower Reservoir Report

Last Updated: December 13, 2025

Located in Oconto Falls, Wisconsin, the Oconto Falls Lower dam stands as a testament to the area's rich history of hydroelectric power generation.


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Summary

Built in 1857, this rockfill dam spans 425 feet across the Oconto River, with a height of 22 feet and a storage capacity of 51 acre-feet. Despite its age, the dam's hazard potential is classified as low, with a moderate risk assessment rating of 3.

Owned and operated by a private entity, the Oconto Falls Lower dam is primarily used for hydroelectric purposes. With a maximum discharge of 5000 cubic feet per second and a spillway width of 186 feet, the dam has played a crucial role in harnessing the power of the river for over a century. Although the dam is not state regulated, it falls under the jurisdiction of the Federal Energy Regulatory Commission for permitting and enforcement purposes.

As an important part of the local landscape, the Oconto Falls Lower dam serves as a reminder of the region's reliance on water resources for energy production. With its historical significance and continued operational capacity, the dam represents a blend of past traditions and modern infrastructure in the ongoing quest for sustainable and renewable energy sources.

Year Completed

1857

Dam Length

425

Dam Height

22

River Or Stream

Oconto River

Primary Dam Type

Rockfill

Surface Area

9

Hydraulic Height

22

Drainage Area

759

Nid Storage

51

Structural Height

22

Outlet Gates

Vertical Lift - 1

Hazard Potential

Low

Foundations

Rock

Nid Height

22
       
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.