Dennis Lake Dam Reservoir Report
Last Updated: December 21, 2025
Dennis Lake Dam, located in Tazewell, Illinois, is a privately owned structure that serves primarily for recreational purposes.
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Summary
Completed in 1970, this earth dam stands at 32 feet high and stretches 461 feet in length, with a storage capacity of 80 acre-feet. Situated on the Sargent Slough-Offstream, the dam is regulated by the Illinois Department of Natural Resources and undergoes regular inspections to ensure its safety and compliance with state regulations.
Despite its low hazard potential, Dennis Lake Dam poses a moderate risk due to its age and limited information on its condition assessment. The dam features an uncontrolled spillway and outlet gates, making it crucial for emergency preparedness and risk management measures to be in place. While the dam has not had any major modifications over the years, a thorough risk assessment and updated emergency action plan would enhance its safety measures and overall resilience in the face of potential climate-related challenges.
As water resource and climate enthusiasts, monitoring the condition and risk profile of structures like Dennis Lake Dam is essential for understanding the broader implications of climate change on water infrastructure. By staying informed about the dam's inspection frequency, hazard potential, and emergency preparedness, we can contribute to the sustainable management of our water resources and ensure the safety of communities downstream.
Year Completed |
1970 |
Dam Length |
461 |
Dam Height |
32 |
River Or Stream |
SARGENT SLOUGH-OFFSTREAM |
Primary Dam Type |
Earth |
Nid Storage |
80 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
32 |
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.
Dennis Lake Dam