Thunderbird Lake Dam Reservoir Report
Nearby: Ingram Pond Dam Gotter Pond Dam
Last Updated: December 22, 2025
Thunderbird Lake Dam, located in Alton on the Mississippi River in Jersey, Illinois, is a privately owned structure designed by the USDA NRCS and completed in 1965.
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Summary
This earth dam stands at a height of 28 feet and spans 300 feet, with a primary purpose of recreation. With a storage capacity of 48 acre-feet and a surface area of 4 acres, Thunderbird Lake Dam serves as a popular spot for water resource and climate enthusiasts to enjoy outdoor activities.
Managed by the state regulatory agency IDNR, Thunderbird Lake Dam is equipped with an uncontrolled spillway and outlet gates. The dam's hazard potential is currently classified as undetermined, with a moderate risk assessment. Although the condition assessment is not available, the dam undergoes regular state inspections and enforcement to ensure safety and compliance. Despite its age, Thunderbird Lake Dam continues to provide recreational opportunities while being monitored for any necessary risk management measures.
For those interested in water resource management and climate resilience, Thunderbird Lake Dam offers a fascinating example of a privately owned earth dam in Illinois. With a rich history dating back to the 1960s and a moderate risk assessment, this recreational structure on the Little Piasa Creek serves as a valuable asset for both locals and visitors alike. As efforts to strengthen dam infrastructure and emergency preparedness continue, Thunderbird Lake Dam remains a key feature in the area's water resource landscape for enthusiasts to explore and appreciate.
Year Completed |
1965 |
Dam Length |
300 |
Dam Height |
28 |
River Or Stream |
TR- LITTLE PIASA CREEK |
Primary Dam Type |
Earth |
Surface Area |
4 |
Drainage Area |
0.23 |
Nid Storage |
48 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Undetermined |
Foundations |
Soil |
Nid Height |
28 |
Seasonal Comparison
Weather Forecast
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.
Thunderbird Lake Dam