Lake Glenn Shoals Dam Reservoir Report
Last Updated: December 6, 2025
Lake Glenn Shoals Dam, located in Montgomery County, Illinois, is a vital structure managed by the local government for flood risk reduction and water supply purposes.
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Summary
Built in 1978 by HURST-ROSCHE, this earth dam stands at a height of 56 feet and spans 1430 feet along the Middle Fork of Shoal Creek. The dam has a storage capacity of 38,900 acre-feet, with a maximum discharge rate of 20,800 cubic feet per second.
The dam's spillway, with a width of 362 feet, is uncontrolled, posing a significant hazard potential. Although its condition assessment is currently unavailable, the dam is inspected every three years to ensure its structural integrity. With a moderate risk rating, the dam is regulated by the Illinois Department of Natural Resources and has been designed for efficient flood risk management. Lake Glenn Shoals Dam serves as a critical infrastructure in safeguarding the local community against flood events and ensuring a stable water supply for the region.
Managed by the St. Louis District of the US Army Corps of Engineers, Lake Glenn Shoals Dam plays a crucial role in the overall water resource management of the area. Despite its age, the dam continues to fulfill its primary purpose of flood risk reduction, highlighting its importance in the region's climate resilience efforts. Climate enthusiasts and water resource professionals alike can appreciate the strategic design and operational capabilities of this essential infrastructure in maintaining the balance between flood protection and sustainable water supply management.
Year Completed |
1978 |
Dam Length |
1430 |
Dam Height |
56 |
River Or Stream |
MIDDLE FORK OF SHOAL CREEK |
Primary Dam Type |
Earth |
Nid Storage |
38900 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
56 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
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.
Lake Glenn Shoals Dam