Thompson Pond Dam Reservoir Report

Last Updated: December 13, 2025

Thompson Pond Dam in Henry County, Illinois, is a privately owned structure that serves as a recreational spot for water resource and climate enthusiasts.


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Summary

Completed in 1972, this Earth-type dam stands at a height of 21 feet and has a length of 300 feet, providing a storage capacity of 76 acre-feet. Situated on the TRIB EDWARDS RIVER in the ANDOVER-OFFSTEAM area, the dam's primary purpose is for recreation, offering opportunities for activities such as fishing, boating, and wildlife observation.

Managed by the Illinois Department of Natural Resources (IDNR), Thompson Pond Dam is regulated, inspected, and enforced by the state, ensuring its safety and compliance with regulations. The dam's hazard potential is classified as low, with a moderate risk assessment score of 3. While the condition assessment is not available, the structure has an uncontrolled spillway type and outlet gates. Despite its age, the dam remains a popular destination for outdoor enthusiasts seeking to enjoy the natural beauty of the surrounding area.

Thompson Pond Dam's location within the Rock Island District adds to its appeal, attracting visitors who appreciate the tranquility and recreational opportunities it offers. With a history dating back to the early 1970s, this beloved landmark continues to provide a safe and enjoyable environment for water resource and climate enthusiasts to explore and appreciate the beauty of Illinois' natural landscapes.

Year Completed

1972

Dam Length

300

Dam Height

21

River Or Stream

TRIB EDWARDS RIVER

Primary Dam Type

Earth

Nid Storage

76

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

21
       
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.