Lake Nellie Dam Reservoir Report
Last Updated: December 5, 2025
Located in Fayette, Illinois, Lake Nellie Dam is a significant earth structure that was completed in 1963 for recreational and water supply purposes.
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Summary
Managed by the local government, this dam on the South Fork Sugar Creek has a height of 41 feet and a length of 460 feet, with a storage capacity of 1478 acre-feet. With a surface area of 67 acres and a drainage area of 2.5 square miles, the dam plays a crucial role in regulating water levels in the region.
Despite its age, Lake Nellie Dam is inspected regularly to ensure its safety and functionality, with the last inspection conducted in May 2019. Classified as having a significant hazard potential, the dam is equipped with uncontrolled spillways and outlets. The risk assessment for the dam is moderate, indicating a need for ongoing monitoring and risk management measures. With a maximum discharge capacity of 6095 cubic feet per second, Lake Nellie Dam remains a key infrastructure for water resource management in the area.
For water resource and climate enthusiasts, Lake Nellie Dam serves as a prime example of the vital role that dams play in providing recreational opportunities and water supply management. With its earth structure design and strategic location on the South Fork Sugar Creek, this dam continues to be a crucial asset for the community of Vandalia and the surrounding area. As efforts continue to monitor and assess the condition of the dam, it underscores the importance of maintaining and managing such structures for the sustainable use of water resources in Illinois.
Year Completed |
1963 |
Dam Length |
460 |
Dam Height |
41 |
River Or Stream |
SOUTH FOEK SUGAR CREEK |
Primary Dam Type |
Earth |
Surface Area |
67 |
Drainage Area |
2.5 |
Nid Storage |
1478 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
41 |
Seasonal Comparison
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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 Nellie Dam