Coles Lake Dam Reservoir Report
Last Updated: December 21, 2025
Located in Rockbridge, Illinois, the Coles Lake Dam serves multiple purposes, including fire protection, stock, and as a small fish pond.
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Summary
Built in 1923, this earth dam stands at a height of 22 feet and has a length of 302 feet. With a storage capacity of 84 acre-feet, the dam is primarily used for recreational activities in the area. The dam is state-regulated by the Illinois Department of Natural Resources, ensuring proper inspection, enforcement, and permitting processes are in place to maintain its integrity.
The Coles Lake Dam poses a low hazard potential and has a moderate risk assessment rating. Despite its age, the dam's condition assessment is not available, indicating a need for further evaluation. With uncontrolled spillways and outlet gates, the dam has a basic infrastructure design but continues to provide essential water resource management for the surrounding community. Regular inspections are conducted every five years to monitor the dam's safety and functionality.
Owned by a private entity, the Coles Lake Dam is situated in a picturesque location along the Trib Rubicon Creek, offering a serene setting for outdoor enthusiasts. With its historical significance dating back almost a century, the dam serves as a vital piece of infrastructure for both water resource management and recreational activities. As climate change continues to impact water resources, maintaining the safety and integrity of dams like Coles Lake Dam is crucial for preserving the environment and ensuring sustainable water management practices in the region.
Year Completed |
1923 |
Dam Length |
302 |
Dam Height |
22 |
River Or Stream |
TRIB RUBICON CREEK |
Primary Dam Type |
Earth |
Nid Storage |
84 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
22 |
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.
Coles Lake Dam