Herrin Reservoir 2 Dam Reservoir Report

Last Updated: December 5, 2025

Herrin Reservoir 2 Dam, located in Carbondale, Illinois, is a key structure along Middle Wolf Creek with a primary purpose of recreation and water supply.


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Summary

Built in 1926 by designer George H. Anderson, this earth dam stands at a height of 27 feet and spans a length of 630 feet. With a storage capacity of 659 acre-feet, the dam plays a crucial role in regulating water levels and providing recreational opportunities for locals and visitors alike.

Managed by a public utility, Herrin Reservoir 2 Dam is regulated by the Illinois Department of Natural Resources and undergoes regular inspections to ensure its structural integrity and safety. The dam's spillway, with a width of 95 feet, is uncontrolled, adding to the significance of this structure in managing water flow in the area. Despite its moderate risk assessment, efforts to maintain and improve the dam's condition are ongoing to mitigate any potential hazards and ensure the safety of surrounding communities.

As a notable feature in Williamson County, Illinois, Herrin Reservoir 2 Dam serves as a vital resource for both water supply and recreational activities. Its historical significance, combined with its functional importance in water management, highlights the importance of maintaining and monitoring this structure to ensure its continued operation and safety for the community.

Year Completed

1926

Dam Length

630

Dam Height

27

River Or Stream

MIDDLE WOLF CREEK

Primary Dam Type

Earth

Nid Storage

659

Outlet Gates

Uncontrolled

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

27
       
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.