Constantine Reservoir Report

Last Updated: December 5, 2025

Constantine is a historic hydroelectric dam located in St.


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Summary

Joseph, Michigan, along the picturesque St. Joseph River. Built in 1873, this gravity dam stands at a height of 30 feet and spans 1515 feet, providing a storage capacity of 5750 acre-feet. With a maximum discharge of 21,000 cubic feet per second, Constantine plays a crucial role in harnessing the river's power for hydroelectric purposes.

Managed by the Federal Energy Regulatory Commission, Constantine is classified as a high hazard potential dam with a moderate risk assessment. The dam features an uncontrolled spillway with a width of 242 feet and seven slide (sluice gate) outlet gates. Despite its age, the condition assessment of Constantine is currently not available, highlighting the need for regular inspections and maintenance to ensure its continued safe operation.

For water resource and climate enthusiasts, Constantine presents a fascinating blend of history, engineering, and environmental impact. As a vital piece of infrastructure in Michigan's water management system, this gravity dam serves as a reminder of our ongoing need to balance energy production with environmental stewardship. With its rich history and crucial role in power generation, Constantine stands as a testament to the enduring importance of sustainable water resource management in the face of climate challenges.

Year Completed

1873

Dam Length

1515

Dam Height

11

River Or Stream

St Joseph River

Primary Dam Type

Gravity

Surface Area

525

Hydraulic Height

27

Drainage Area

1543

Nid Storage

5750

Structural Height

30

Outlet Gates

Slide (sluice gate) - 7

Hazard Potential

High

Foundations

Soil

Nid Height

30
       
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.