Otter Lake Diversion Dam Reservoir Report

Last Updated: December 5, 2025

Built in 1979, the Otter Lake Diversion Dam in Baraga, Michigan, serves as a crucial structure along the Sturgeon River for flood risk reduction and recreation purposes.


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Summary

This gravity dam stands at 11 feet high and spans 197 feet in length, with a storage capacity of 30,800 acre-feet. While primarily owned by the local government, it is also regulated and inspected by the Michigan Department of Environment, Great Lakes, and Energy (DEGLE) to ensure its safe operation and compliance with state regulations.

Despite its low hazard potential, the dam has a moderate risk assessment rating, indicating the need for ongoing monitoring and risk management measures. The uncontrolled spillway, with a width of 78 feet, helps to manage excess water flow during periods of heavy rainfall or snowmelt. Although last inspected in 1989, the dam's condition is currently listed as "Not Rated," highlighting the importance of regular assessments to ensure its structural integrity and safety for surrounding communities.

With its scenic location and vital role in flood protection, the Otter Lake Diversion Dam stands as a testament to the intersection of water resource management and climate resilience. As climate change continues to impact the frequency and intensity of extreme weather events, structures like this dam play a crucial role in safeguarding communities and ecosystems against potential flooding and water-related disasters.

Year Completed

1979

Dam Length

197

Dam Height

11

River Or Stream

Sturgeon River

Primary Dam Type

Gravity

Surface Area

700

Hydraulic Height

11

Nid Storage

30800

Structural Height

11

Hazard Potential

Low

Nid Height

11
       
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.