Cilca Lake Dam Reservoir Report
Last Updated: December 25, 2025
Cilca Lake Dam, located in Petersburg, Illinois, is a privately-owned earth dam with a primary purpose of recreation.
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Summary
Constructed in 1968 by the USDA NRCS, this dam stands at a height of 43 feet and has a length of 505 feet. The dam has a storage capacity of 164 acre-feet, with a normal storage level of 126 acre-feet. The spillway width is 143 feet, and the dam is classified as having a low hazard potential.
The dam is regulated by the Illinois Department of Natural Resources and undergoes state inspections regularly. While the condition assessment is not available, the risk assessment categorizes the dam as having a moderate risk level. The surrounding area of Cilca Lake Dam is prone to moderate flooding, with the Sangamon River tributary nearby. The dam does not have any associated locks or outlet gates, and there have been no significant modifications to the structure since its completion.
Overall, Cilca Lake Dam serves as a vital recreational resource in the Sangamon County area, providing opportunities for water enthusiasts and climate lovers to enjoy the beauty of the surrounding landscape. The dam's maintenance and regulatory oversight ensure its continued safety and functionality for the community to appreciate for years to come.
Year Completed |
1968 |
Dam Length |
505 |
Dam Height |
43 |
River Or Stream |
TRIB SANGAMON RIVER |
Primary Dam Type |
Earth |
Nid Storage |
164 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
43 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Spring Creek At Springfield
|
2cfs |
Sangamon River At Petersburg
|
166cfs |
Sangamon River At Riverton
|
131cfs |
South Fork Sangamon River Nr Rochester
|
25cfs |
Salt Creek Near Greenview
|
149cfs |
Lake Fork Near Cornland
|
9cfs |
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.
Cilca Lake Dam