Wausau Detached Reservoir Report

Last Updated: December 6, 2025

Wausau Detached is a captivating hydroelectric structure located in Marathon, Wisconsin, along the beautiful Wisconsin River.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1930, this gravity dam stands at 28 feet high and spans 339 feet in length, with a storage capacity of 2800 acre-feet. The dam serves multiple purposes, including hydroelectric power generation and recreational activities, making it a vital asset for the region.

Managed by the Federal Energy Regulatory Commission, Wausau Detached boasts a controlled spillway and two Tainter radial gates for water discharge control. Despite its low hazard potential, the dam is rated with a very high risk assessment due to its age and structural condition assessment that is currently not available. With a designated emergency action plan and regular inspection frequency, the dam is well-prepared to handle any potential risks and ensure the safety of the surrounding communities.

The picturesque scenery and functional design of Wausau Detached make it a must-visit destination for water resource and climate enthusiasts. With its historical significance and environmental impact, this hydroelectric structure continues to play a crucial role in providing sustainable energy and recreational opportunities for the residents of Marathon, Wisconsin.

Year Completed

1930

Dam Length

339

Dam Height

28

River Or Stream

Wisconsin River

Primary Dam Type

Gravity

Surface Area

304

Hydraulic Height

27.5

Drainage Area

3092

Nid Storage

2800

Structural Height

28

Outlet Gates

Other Controlled - 1, Tainter (radial) - 2

Hazard Potential

Low

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.