Johnson Lake Dam Reservoir Report
Last Updated: December 6, 2025
Johnson Lake Dam, located in Enterprise, Illinois, stands as a critical infrastructure designed by RHUTASEL & ASSOC.
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Summary
in 2002 for the primary purpose of debris control. This private-owned dam, regulated by the Illinois Department of Natural Resources, spans 400 feet in length and reaches a height of 20 feet, with a storage capacity of 110 acre-feet. Situated on the TRIB ENDSLEY CREEK, the dam plays a significant role in managing water resources and mitigating flood risks in the Wayne County area.
With a low hazard potential and a moderate risk assessment rating, Johnson Lake Dam has a spillway width of 16 feet and a maximum discharge capacity of 213 cubic feet per second. The dam's structure, primarily made of earth and stone, covers a surface area of 7 acres and serves as a recreational spot for enthusiasts. Despite its age, the dam undergoes regular inspections every five years to ensure its structural integrity and safety, showcasing a commitment to water resource management and climate resilience in the region.
Overall, Johnson Lake Dam stands as a vital component of the water infrastructure in Wayne County, Illinois, serving not only for debris control but also providing recreational opportunities for the local community. With its state-regulated status and adherence to inspection protocols, the dam exemplifies a commitment to water resource management and environmental stewardship. As climate change impacts continue to affect water resources, the importance of structures like Johnson Lake Dam in maintaining water security and flood control cannot be overstated.
Year Completed |
2002 |
Dam Length |
400 |
Dam Height |
20 |
River Or Stream |
TRIB ENDSLEY CREEK |
Primary Dam Type |
Earth |
Surface Area |
7 |
Drainage Area |
0.16 |
Nid Storage |
110 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
20 |
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.
Johnson Lake Dam