Hillsdale Millpond Dam Reservoir Report

Last Updated: December 5, 2025

The Hillsdale Millpond Dam, located in Hillsdale, Michigan, is a vital structure regulating the flow of the Saint Joseph River.


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Summary

Built in 1837, this earth dam stands at a height of 14 feet and stretches 307 feet in length, with a storage capacity of 100 acre-feet. The primary purpose of the dam is for recreation, providing a surface area of 11 acres for water enthusiasts to enjoy.

Managed by the local government and regulated by the Michigan DEGLE, the dam has a significant hazard potential and is classified as having a fair condition assessment. With a maximum discharge of 730 cubic feet per second and an uncontrolled spillway width of 27 feet, the dam poses a moderate risk (3) to the surrounding area. Regular inspections are conducted, with the last assessment taking place on October 19, 2020, to ensure the safety and integrity of the structure.

Water resource and climate enthusiasts will find the Hillsdale Millpond Dam a fascinating site to explore, offering insights into dam engineering, water management, and environmental risk assessment. As a historic structure with a rich legacy dating back to the 19th century, this dam serves as a reminder of the importance of sustainable water resource management in the face of changing climate conditions.

Year Completed

1837

Dam Length

307

Dam Height

14

River Or Stream

Saint Joseph River

Primary Dam Type

Earth

Surface Area

11

Hydraulic Height

14

Drainage Area

9.4

Nid Storage

100

Structural Height

14

Hazard Potential

Significant

Nid Height

14
       
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.