Millecoquins Creek Dam Reservoir Report

Last Updated: December 5, 2025

Millecoquins Creek Dam, located in Mackinac County, Michigan, is a state-regulated structure with a primary purpose of recreation.


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Summary

Completed in 1965, this earth dam stands at a height of 18 feet and has a hydraulic height of 15 feet. With a length of 144 feet, the dam provides a storage capacity of 58 acre-feet, with a normal storage level of 42 acre-feet. The dam is situated on the Upper Millecoquin River, within the Detroit District of the US Army Corps of Engineers.

Despite its low hazard potential and satisfactory condition assessment, Millecoquins Creek Dam is subject to regular state inspections and enforcement measures by the Michigan Department of Environment, Great Lakes, and Energy (DEGLE). The structure features an uncontrolled spillway with a width of 3 feet, capable of discharging a maximum flow of 64 cubic feet per second. The risk assessment for the dam is moderate, indicating a level 3 risk, although specific risk management measures have not been detailed.

Overall, Millecoquins Creek Dam presents an intriguing case study for water resource and climate enthusiasts, showcasing the intersection of recreational infrastructure, regulatory oversight, and risk management in the context of dam operations. Its historical significance, engineering design, and environmental impact make it a compelling subject for further study and analysis within the broader context of water resource management and climate resilience efforts.

Year Completed

1965

Dam Length

144

Dam Height

18

River Or Stream

Trib Upper Millecoquin River

Primary Dam Type

Earth

Surface Area

8

Hydraulic Height

15

Drainage Area

0.25

Nid Storage

58

Structural Height

18

Hazard Potential

Low

Nid Height

18
       
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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.