Thomson Dam No 6 Reservoir Report

Last Updated: December 5, 2025

Thomson Dam No 6, located in Thomson, Minnesota, is an impressive structure that serves multiple purposes, including hydroelectric power generation and recreation.


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Summary

Built in 1907, this dam stands at a height of 51.6 feet and has a storage capacity of 4,352 acre-feet. Situated on the St. Louis River, it plays a crucial role in water resource management in Carlton County.

Managed by the Federal Energy Regulatory Commission, Thomson Dam No 6 is subject to regular inspections and enforcement to ensure its safety and compliance with regulations. With a high hazard potential, the dam is closely monitored to prevent any potential risks to the surrounding area. Despite its age, the dam continues to be a key feature in the region's water infrastructure, providing essential services to the community and supporting the local economy.

As a significant landmark in the area, Thomson Dam No 6 not only contributes to the generation of clean energy but also offers recreational opportunities for residents and visitors. With its historical significance and important role in water resource management, the dam stands as a testament to the ingenuity and engineering prowess of its time, continuing to serve the needs of the community while preserving the natural beauty of the St. Louis River.

Year Completed

1907

Dam Length

125

Dam Height

51

River Or Stream

St Louis River

Surface Area

375

Hydraulic Height

51.6

Nid Storage

4352

Structural Height

51.6

Hazard Potential

High

Nid Height

52
       
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.