Tall Timbers Lake East Dam Reservoir Report
Last Updated: December 30, 2025
Tall Timbers Lake East Dam, located in Macoupin County, Illinois, is a private earth dam constructed in 1921 for recreational purposes.
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Summary
Standing at a height of 14 feet and stretching 515 feet in length, the dam serves to create Tall Timbers Lake East, offering a storage capacity of 90 acre-feet. The dam, regulated by the Illinois Department of Natural Resources, is classified as having a low hazard potential, with a moderate risk assessment score of 3.
Despite its age, the dam has not undergone any recent condition assessments, and its emergency action plan status remains unknown. With uncontrolled spillway and outlet gates, the structure poses minimal risk to surrounding areas. The last recorded inspection in July 2017 indicated a low hazard potential, pointing to the overall stability and safety of the dam. For water resource and climate enthusiasts, Tall Timbers Lake East Dam presents a unique opportunity to explore the intersection of recreational water management and infrastructure maintenance in a historic setting.
Year Completed |
1921 |
Dam Length |
515 |
Dam Height |
14 |
River Or Stream |
TRIB EAST CREEK |
Primary Dam Type |
Earth |
Nid Storage |
90 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
14 |
Seasonal Comparison
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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.
Tall Timbers Lake East Dam