Lac Vieux Desert Reservoir Report

Last Updated: December 5, 2025

Lac Vieux Desert, located in Vilas, Wisconsin, is a hydroelectric dam with a primary purpose of flood risk reduction, hydroelectric power generation, and recreation.


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Summary

Completed in 1870, this gravity dam stands at 7 feet high and is supported by stone foundations. With a storage capacity of 20,000 acre-feet and a surface area of 5,066 acres, Lac Vieux Desert plays a crucial role in managing water resources in the area.

Managed by the Federal Energy Regulatory Commission, Lac Vieux Desert has a significant hazard potential and a very high risk assessment rating. The dam features a controlled spillway and Tainter (radial) outlet gates, ensuring the safe release of water during high discharge events. Despite being in operation for over a century, the dam's condition assessment is currently not rated, emphasizing the importance of regular inspections and maintenance to ensure its continued safety and effectiveness for both water management and hydroelectric power generation.

As a key structure in the region, Lac Vieux Desert serves as a vital resource for the community, providing essential flood control measures, renewable energy production, and recreational opportunities. Its location on the Wisconsin River, along with its historical significance and engineering design, make it a notable site for water resource and climate enthusiasts to study and appreciate the intersection of human infrastructure with natural landscapes.

Years Modified

1938 - Other

Year Completed

1870

Dam Length

50

Dam Height

7

River Or Stream

WISCONSIN

Primary Dam Type

Gravity

Surface Area

5066

Hydraulic Height

7

Drainage Area

21

Nid Storage

20000

Structural Height

7

Outlet Gates

Tainter (radial) - 1

Hazard Potential

Significant

Foundations

Soil

Nid Height

7
       
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.