East Fork Lake Dam Reservoir Report
Nearby: Webber Lake Dam M. D. Borah Lake Dam
Last Updated: December 10, 2025
East Fork Lake Dam, located in Olney, Illinois, stands as a testament to the importance of water resource management and climate resilience.
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Summary
Built in 1972 by Warren & Van Praag, Inc., this earth dam serves multiple purposes, primarily focusing on recreation and water supply. With a height of 84 feet and a length of 6500 feet, the dam holds a maximum storage capacity of 22,680 acre-feet, providing a critical source of water for the surrounding area.
Managed by the local government and regulated by the Illinois Department of Natural Resources, East Fork Lake Dam plays a vital role in flood control and water management along the East Fork Fox River. The dam's uncontrolled spillway, with a width of 629 feet, helps mitigate high hazard potential during extreme weather events. Despite its high hazard potential, the dam's risk assessment remains at a moderate level (3), reflecting ongoing efforts to ensure the safety and integrity of the structure.
With its scenic location and recreational opportunities, East Fork Lake Dam is not only a crucial water resource but also a popular destination for outdoor enthusiasts. As climate change continues to impact water availability and quality, the management and maintenance of dams like East Fork Lake are essential in ensuring sustainable water management practices for future generations.
Year Completed |
1972 |
Dam Length |
6500 |
Dam Height |
84 |
River Or Stream |
EAST FORK FOX RIVER |
Primary Dam Type |
Earth |
Surface Area |
930 |
Drainage Area |
10.4 |
Nid Storage |
22680 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
84 |
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.
East Fork Lake Dam