Hubbard Lake Dam Reservoir Report

Last Updated: December 5, 2025

Hubbard Lake Dam, located in Hubbard Lake, Michigan, was completed in 1890 and serves as a crucial structure for hydroelectric purposes on the South Branch Thunder Bay River.


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Summary

This private dam, with a gravity design and a height of 11 feet, has a storage capacity of 35,200 acre-feet and covers a surface area of 8,800 acres. With a maximum discharge of 1,100 cubic feet per second, the dam plays a significant role in managing water resources in the region.

Despite being classified as a low hazard potential structure, Hubbard Lake Dam is considered to have a very high risk level, emphasizing the importance of proper risk management measures. While the dam's condition assessment is currently marked as 'Not Rated,' the last inspection in August 2010 noted a five-year inspection frequency. The dam has a controlled spillway type with a width of 16 feet, ensuring a safe and controlled release of excess water during high flow events. Overall, Hubbard Lake Dam stands as a historical landmark and vital infrastructure for water resource management and hydroelectric power generation in Michigan.

Year Completed

1890

Dam Length

108

Dam Height

11

River Or Stream

South Br Thunder Bay River

Primary Dam Type

Gravity

Surface Area

8800

Hydraulic Height

11

Drainage Area

14.6

Nid Storage

35200

Structural Height

11

Hazard Potential

Low

Nid Height

11
       
Seasonal Comparison

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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.