Lake Of Egypt Dam Reservoir Report

Last Updated: December 5, 2025

Lake of Egypt Dam, located in Marion, Illinois, is a vital structure along the South Fork Saline River.


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Summary

Built in 1962 by BURNS & MCDONNELL ENGINEERS, this earth dam stands at 55 feet high and spans a length of 2850 feet, creating a reservoir with a maximum storage capacity of 82,942 acre-feet. The dam serves multiple purposes, including recreation and water resource management, with a normal storage capacity of 41,215 acre-feet and a surface area of 2,265 acres.

The dam's spillway type is uncontrolled, with a spillway width of 200 feet, and it has a high hazard potential, indicating the need for regular inspections and risk management measures. Although the current condition assessment is not available, the dam is under state regulation, permitting, inspection, and enforcement by the Illinois Department of Natural Resources. Despite its age, Lake of Egypt Dam continues to be a significant asset for the region, providing water supply, recreational opportunities, and flood control for the surrounding area.

With its picturesque location and important role in water resource management, Lake of Egypt Dam stands as a testament to engineering ingenuity and the essential relationship between humans and the environment. As climate change impacts water resources, structures like Lake of Egypt Dam play a crucial role in safeguarding communities and ecosystems. By ensuring proper maintenance and oversight, this dam remains a key element in the sustainable management of water in Illinois.

Year Completed

1962

Dam Length

2850

Dam Height

55

River Or Stream

SOUTH FORK SALINE RIVER

Primary Dam Type

Earth

Surface Area

2265

Drainage Area

33.3

Nid Storage

82942

Outlet Gates

Uncontrolled

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

55
       
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.