Mcwilliams Pond Dam 1 Reservoir Report

Last Updated: December 6, 2025

Mcwilliams Pond Dam 1, located in Montgomery County, Illinois, is a privately owned structure with a primary purpose of serving as a Fish and Wildlife Pond.


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Summary

Built in 1970 by the USDA NRCS, this earth dam stands at a height of 30 feet and spans a length of 400 feet, creating a storage capacity of 38 acre-feet. Situated on the TR- SHOAL CREEK E W FORK river, the dam is regulated by the Illinois Department of Natural Resources and undergoes regular inspections to ensure its safety and functionality.

Despite being classified as having a low hazard potential, Mcwilliams Pond Dam 1 poses a moderate risk due to its condition assessment being listed as "Not Available." The dam features an uncontrolled spillway and outlet gates, with a maximum discharge of 232 cubic feet per second. With a drainage area of 0.09 square miles, the dam provides recreational opportunities while also supporting the local fish and wildlife population. The surrounding area offers a tranquil setting for water resource and climate enthusiasts to appreciate the importance of sustainable dam management practices.

While the specifics of the dam's emergency action plan and risk management measures are not provided, the presence of state permitting, inspection, and enforcement mechanisms ensures that Mcwilliams Pond Dam 1 is being monitored and maintained in accordance with regulatory standards. As a vital component of the local ecosystem, this dam serves as a reminder of the interconnectedness between water resources, climate considerations, and the need for responsible stewardship of our natural environment.

Year Completed

1970

Dam Length

400

Dam Height

30

River Or Stream

TR- SHOAL CREEK E W FORK

Primary Dam Type

Earth

Surface Area

4

Drainage Area

0.09

Nid Storage

38

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Soil

Nid Height

30
       
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.