Mcginnis Lake Dam Reservoir Report

Last Updated: December 5, 2025

Mcginnis Lake Dam, located in Grand Blanc, Michigan, is a state-owned structure primarily used for recreation purposes.


°F

°F

mph

Wind

%

Humidity

Summary

Built in 1978, this earth dam stands at a height of 19 feet and has a hydraulic height of 14 feet, with a length of 400 feet. The dam has a normal storage capacity of 16 acre-feet and a maximum storage capacity of 125 acre-feet, serving as a vital resource for the surrounding area.

With an uncontrolled spillway width of 15 feet, Mcginnis Lake Dam has a low hazard potential and is currently assessed to be in fair condition as of October 2020. The dam is inspected every five years, with the most recent inspection revealing moderate risk levels. Despite its moderate risk assessment, the dam is equipped to handle a maximum discharge of 200 cfs and plays a crucial role in managing water resources for the tributary to Thread Creek.

As a significant feature in the region, Mcginnis Lake Dam provides not only recreational opportunities but also serves as a crucial resource for water management. With its strategic location and moderate risk assessment, the dam is an essential component in the overall infrastructure of Michigan's water resource system.

Year Completed

1978

Dam Length

400

Dam Height

19

River Or Stream

Tributary to Thread Creek

Primary Dam Type

Earth

Surface Area

25

Hydraulic Height

14

Drainage Area

0.41

Nid Storage

125

Structural Height

19

Hazard Potential

Low

Nid Height

19
       
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.