Lake Thunderbird Dam Reservoir Report

Last Updated: December 21, 2025

Lake Thunderbird Dam, located in Putnam, Illinois, stands as a vital source of recreation and water resource management in the region.


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Summary

Constructed in 1970 by FARGO ENGINEERING, this private earth dam boasts a height of 86 feet and a length of 910 feet, creating a reservoir with a maximum storage capacity of 3,844 acre-feet. The dam, situated on the TRIB SENACHWINE CREEK, serves as a popular destination for outdoor enthusiasts seeking activities such as fishing, boating, and picnicking.

Managed by the Illinois Department of Natural Resources (IDNR), Lake Thunderbird Dam is subject to regular inspections and enforcement measures to ensure its structural integrity and safety. With a spillway width of 120 feet and a maximum discharge capacity of 3,320 cubic feet per second, the dam is equipped to handle high hazard potential situations. Though the condition assessment is not currently available, the dam's risk assessment indicates a moderate level of risk, prompting the need for ongoing risk management measures and emergency action planning. Despite these challenges, Lake Thunderbird Dam remains a cornerstone of the local community, providing both recreational opportunities and essential water resource management functions.

Year Completed

1970

Dam Length

910

Dam Height

86

River Or Stream

TRIB SENACHWINE CREEK

Primary Dam Type

Earth

Surface Area

109

Drainage Area

2.9

Nid Storage

3844

Outlet Gates

Uncontrolled

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

86
       
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.