Old Mt. Olive City Lake Dam Reservoir Report
Nearby: Lake Ka-Ho 2 Dam Lake Ka-Ho 1 Dam
Last Updated: December 30, 2025
Old Mt.
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Summary
Olive City Lake Dam, located in Macoupin, Illinois, stands as a significant structure for both recreation and water supply purposes. Completed in 1900, this earth dam stretches 380 feet in length and reaches a height of 37 feet, offering a storage capacity of 539 acre-feet. Situated on Sugar Creek, the dam's primary purpose is recreational enjoyment, providing a serene escape for locals and visitors alike.
Managed by the local government, the dam is regulated by the Illinois Department of Natural Resources (IDNR) and undergoes regular inspections to ensure its safety and integrity. With a spillway width of 45 feet and a maximum discharge of 1414 cubic feet per second, the dam's hazard potential is deemed significant, prompting a moderate risk assessment rating of 3. While the condition assessment is currently unavailable, the dam's emergency action plan status and risk management measures remain unspecified.
As part of the St. Louis District, Old Mt. Olive City Lake Dam offers a tranquil retreat for water resource and climate enthusiasts to appreciate the beauty of nature while recognizing the importance of proper dam management and safety protocols. Its historical significance, combined with its recreational and water supply functions, makes it a vital asset within the community, requiring ongoing monitoring and maintenance to uphold its role in serving both human and environmental needs.
Year Completed |
1900 |
Dam Length |
380 |
Dam Height |
37 |
River Or Stream |
SUGAR CREEK |
Primary Dam Type |
Earth |
Surface Area |
37 |
Drainage Area |
0.8 |
Nid Storage |
539 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
37 |
Seasonal Comparison
Weather Forecast
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.
Old Mt. Olive City Lake Dam