Lake Joy Dam Reservoir Report

Last Updated: December 6, 2025

Lake Joy Dam, located in Posey-Offstream, Illinois, is a privately owned structure regulated by the Illinois Department of Natural Resources.


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Summary

Built in 1946, this earth dam stands at a height of 23 feet and spans 292 feet in length, with a storage capacity of 87 acre-feet. The primary purpose of Lake Joy Dam is for recreation, offering opportunities for boating, fishing, and other water-based activities in the area.

Despite being classified as having a low hazard potential, Lake Joy Dam is subject to regular inspections and enforcement by the state regulatory agency to ensure its safety and functionality. The dam features an uncontrolled spillway and outlet gates, with an inspection frequency of every 5 years. While the condition assessment is currently unavailable, the risk assessment is moderate, indicating the importance of continued monitoring and maintenance to mitigate any potential risks associated with the structure.

Overall, Lake Joy Dam serves as a vital resource for water recreation enthusiasts in the Clinton County area, offering a picturesque setting for outdoor activities. With its historical significance and moderate risk profile, efforts are ongoing to ensure the dam's safety and compliance with regulatory standards to protect both the environment and the surrounding community.

Year Completed

1946

Dam Length

292

Dam Height

23

River Or Stream

TRIB LITTLE YORK BRANCH

Primary Dam Type

Earth

Nid Storage

87

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

23
       
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.