Pettysville Mill Dam Reservoir Report

Last Updated: December 5, 2025

Located in Livingston, Michigan, the Pettysville Mill Dam, also known as the Mill House & Flume Dam, is a privately owned structure on Chilson Creek.


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Summary

Built in 1840, this Earth and Gravity dam stands at a height of 21 feet with a length of 370 feet, providing 85 acre-feet of storage capacity for recreational purposes. The dam is regulated and inspected by the Michigan Department of Environment, Great Lakes, and Energy (DEGLE), ensuring compliance with state regulations.

Despite being in fair condition as of the last assessment in 2009, the Pettysville Mill Dam is classified as having a significant hazard potential, with a very high risk level assigned. The dam features a controlled spillway with a width of 5 feet and is located in a picturesque setting, offering a surface area of 5 acres for recreational activities. With the dam's historical significance dating back over a century, its presence adds to the charm of the surrounding landscape and provides valuable water resource management in the area.

As water resource and climate enthusiasts explore the Pettysville Mill Dam, they can appreciate its role in the local ecosystem and the recreational opportunities it offers. The dam's presence on Chilson Creek contributes to the overall water management strategy in the region, while its historical and structural significance adds to the cultural heritage of the area. With ongoing inspections and regulatory oversight, the Pettysville Mill Dam remains a vital part of the landscape, blending functionality with historical charm for visitors and residents alike.

Year Completed

1840

Dam Length

370

Dam Height

21

River Or Stream

Chilson Creek

Primary Dam Type

Earth

Surface Area

5

Hydraulic Height

21

Drainage Area

11

Nid Storage

85

Structural Height

21

Hazard Potential

Significant

Nid Height

21
       
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.