Crescent Lake Dam Reservoir Report

Last Updated: December 13, 2025

Crescent Lake Dam, located in Ophiem, Henry, Illinois, is a privately owned earth dam completed in 1900 primarily designed for recreational purposes.


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Summary

With a dam height of 31 feet and a length of 475 feet, the dam provides a storage capacity of 249 acre-feet, with a normal storage level of 186 acre-feet. The dam is situated on the tributaries of Mud Creek and Edwards Creek, making it an essential water resource in the area.

Managed by the Illinois Department of Natural Resources, Crescent Lake Dam is regulated, permitted, inspected, and enforced by the state agency to ensure its safety and compliance with regulations. The dam has an uncontrolled spillway and outlet gates, with a significant hazard potential and a moderate risk level assessed. While the condition assessment of the dam is not available, regular inspections are conducted every three years, with the last inspection carried out in April 2018.

For water resource and climate enthusiasts, Crescent Lake Dam offers a fascinating glimpse into the intersection of human engineering and environmental conservation. As a recreational dam in a picturesque location, it serves as a vital water source for the community while facing challenges of potential hazards and the need for risk management measures. Its historical significance and ongoing regulatory oversight make it a noteworthy site for those interested in water infrastructure and climate resilience efforts.

Year Completed

1900

Dam Length

475

Dam Height

31

River Or Stream

TRIB MUD CREEK, EDWARDS CREEK

Primary Dam Type

Earth

Nid Storage

249

Outlet Gates

Uncontrolled

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

31
       
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.