Illinois Power Company Lake Dam Reservoir Report
Last Updated: December 26, 2025
Illinois Power Company Lake Dam, located in Hillery, Illinois, stands as a testament to engineering excellence with its primary purpose being recreation.
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Summary
Built in 1954 by HARZA ENGINEERING CO., this earth dam with a buttress core type spans 500 feet in length and reaches a height of 80 feet, providing a storage capacity of 2400 acre-feet for the Vermillion River. The dam's spillway, with a width of 30 feet, is uncontrolled, adding an element of natural beauty to the surroundings.
Managed by the Illinois Department of Natural Resources (IDNR), the Illinois Power Company Lake Dam boasts a low hazard potential, making it a safe and enjoyable spot for water resource and climate enthusiasts. Despite its age, with the last inspection conducted in November 2020, the dam continues to fulfill its intended purpose efficiently. With a moderate risk assessment rating, the dam's risk management measures ensure the safety of the surrounding community and environment.
As a part of the Louisville District, Illinois Power Company Lake Dam remains a vital structure in Vermilion County, serving as a recreational hub for locals and visitors alike. Its historical significance, coupled with its sound engineering and regulatory oversight, make it a noteworthy destination for those interested in water resource management and climate resilience.
Year Completed |
1954 |
Dam Length |
500 |
Dam Height |
80 |
River Or Stream |
VERMILLION RIVER |
Primary Dam Type |
Earth |
Nid Storage |
2400 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
80 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Illinois Power Company Lake Dam