Timber Lake Dam Reservoir Report

Last Updated: December 22, 2025

Timber Lake Dam, located in Tower Lake, Illinois, is a private dam primarily used for recreation purposes.


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Summary

Completed in 1949, this earth dam stands at a height of 20 feet and spans a length of 320 feet, with a storage capacity of 292 acre-feet. While the dam is categorized as having a low hazard potential, it is regulated by the Illinois Department of Natural Resources (IDNR) and undergoes regular inspections to ensure its safety and compliance with state regulations.

Despite its low hazard potential, Timber Lake Dam presents a moderate risk level, as indicated by a risk assessment rating of 3. The dam features an uncontrolled spillway and is not equipped with outlet gates. Although the condition assessment is marked as "Not Available," the dam has a history of regular inspections with a frequency of every five years, with the last inspection conducted in July 2017. While emergency action plans and risk management measures are not explicitly documented, the dam remains a significant feature in the local landscape, contributing to the recreational and environmental appeal of the area.

Timber Lake Dam serves as a vital component in the local water resource infrastructure, providing recreational opportunities while also posing a moderate risk level that necessitates ongoing monitoring and management. As a private dam regulated by the IDNR, its maintenance and safety are paramount to ensure the protection of surrounding communities and the preservation of water resources in Lake County, Illinois. With a history dating back to 1949, Timber Lake Dam stands as a testament to the intersection of human-made structures and natural environments, highlighting the importance of responsible stewardship in the face of evolving climate challenges.

Year Completed

1949

Dam Length

320

Dam Height

20

River Or Stream

TRIB TOWER LAKE

Primary Dam Type

Earth

Nid Storage

292

Outlet Gates

None

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

20
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.