Hamlin Lake Dam Reservoir Report

Last Updated: December 5, 2025

Hamlin Lake Dam, located in Ludington State Park, Michigan, stands as a testament to both man-made ingenuity and natural beauty.


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Summary

Completed in 1913, this gravity dam on the Big Sable River serves primarily for recreational purposes, offering visitors a picturesque backdrop for outdoor activities. With a height of 23 feet and a hydraulic height of 21.6 feet, the dam creates a reservoir with a normal storage capacity of 85,600 acre-feet and a maximum storage of 102,500 acre-feet.

Despite its serene appearance, Hamlin Lake Dam carries a high hazard potential, prompting regular inspections by the Michigan Department of Environment, Great Lakes, and Energy (DEGLE). The dam's condition was last assessed as satisfactory in July 2019, with a moderate risk level assigned. Emergency action plans are in place, although their last revision dates back to 2015. The dam's spillway, an uncontrolled type with a width of 94 feet, ensures the safe release of excess water when needed, guarding against potential flooding downstream.

Surrounded by the natural beauty of Mason County, Michigan, Hamlin Lake Dam serves as a vital link between water resource management and recreational enjoyment. As climate change impacts the region, ensuring the safety and integrity of this historic structure becomes increasingly crucial. With its rich history and scenic location, Hamlin Lake Dam continues to be a popular destination for water resource and climate enthusiasts seeking to explore the intersection of human engineering and environmental stewardship.

Year Completed

1913

Dam Length

206

Dam Height

23

River Or Stream

Big Sable River

Primary Dam Type

Gravity

Surface Area

4750

Hydraulic Height

21.6

Drainage Area

206

Nid Storage

102500

Structural Height

23

Hazard Potential

High

Nid Height

23
       
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.