Sharon Mills Dam Reservoir Report

Last Updated: December 5, 2025

Sharon Mills Dam, located in Manchester, Michigan, is a concrete structure built in 1930 on the River Raisin.


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Summary

This dam serves primarily for recreational purposes, with a low hazard potential and satisfactory condition assessment. With a height of 10 feet and a hydraulic height of 9.3 feet, the dam has a storage capacity of 260 acre-feet and a maximum discharge rate of 1700 cubic feet per second.

The dam covers a surface area of 46 acres and has a drainage area of 128 square miles. It features an uncontrolled spillway with a width of 74 feet. The last inspection in October 2017 reported the structure as being in satisfactory condition, meeting regulatory requirements for inspection, enforcement, and permitting. The risk assessment for Sharon Mills Dam indicates a moderate level of risk (3) with no significant risk management measures identified at this time.

Overall, Sharon Mills Dam is a key feature in the recreational landscape of Washtenaw County, Michigan, providing both environmental and recreational benefits to the local community. As climate change impacts water resources, monitoring and maintaining dams like Sharon Mills become increasingly important for ensuring public safety and the sustainable management of waterways.

Year Completed

1930

Dam Length

365

Dam Height

10

River Or Stream

River Raisin

Primary Dam Type

Concrete

Surface Area

46

Hydraulic Height

9.3

Drainage Area

128

Nid Storage

260

Structural Height

10

Hazard Potential

Low

Nid Height

10
       
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.