Forest Lemon Dam Reservoir Report
Nearby: Le Baube Lake Dam Cross Lake Dam
Last Updated: December 21, 2025
Forest Lemon Dam, also known as Timberline Recreation Area, is a rockfill dam located in Mackinaw, Illinois.
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Summary
Built in 1965 by the USDA NRCS, the primary purpose of this dam is for recreation, offering visitors a serene environment to enjoy nature. With a height of 26 feet and a length of 365 feet, the dam provides a storage capacity of 55 acre-feet, making it a valuable asset for water resource management in the area.
Managed by the Illinois Department of Natural Resources, Forest Lemon Dam is state-regulated and undergoes regular inspections to ensure its structural integrity and safety. Despite its low hazard potential, the dam is considered to have a moderate risk level, indicating the importance of proper risk management measures. While its spillway is uncontrolled, the dam's design and location on the tributary of Mackinaw River make it a crucial component in the local watershed management system.
As a key feature in the Chicago District's water infrastructure, Forest Lemon Dam not only serves as a recreational area but also plays a vital role in flood control and water supply management. With its scenic surroundings and strategic location, the dam serves as a testament to the successful collaboration between federal and state agencies in ensuring the sustainable use of water resources in Illinois.
Year Completed |
1965 |
Dam Length |
365 |
Dam Height |
26 |
River Or Stream |
TRIB MACKINAW R |
Primary Dam Type |
Rockfill |
Nid Storage |
55 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
26 |
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.
Forest Lemon Dam