Alleman Lake Dam Reservoir Report
Last Updated: December 14, 2025
Alleman Lake Dam, located in LaSalle, Illinois, along the TRIB VERMILION RIVER, is a privately owned structure primarily used for recreation purposes.
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Summary
Built in 1975, this earth dam stands at a height of 26 feet and stretches 1285 feet in length, providing a maximum storage capacity of 80 acre-feet of water. Despite its uncontrolled spillway and outlet gates, the dam has a low hazard potential and a moderate risk assessment rating, indicating a moderate level of risk associated with its operation.
Managed by the Illinois Department of Natural Resources (IDNR), Alleman Lake Dam is subject to state regulation, permitting, inspection, and enforcement. The dam's last inspection in 2011 revealed no available condition assessment, suggesting a need for updated evaluations to ensure its safety and functionality. While the dam's Emergency Action Plan (EAP) status and risk management measures are not specified, its risk assessment level of moderate highlights the importance of continued monitoring and maintenance to mitigate potential hazards and protect downstream communities.
With its scenic location and recreational purpose, Alleman Lake Dam serves as a popular spot for outdoor enthusiasts in the Lowell area. Although it is not operated by the US Army Corps of Engineers, the dam's position within the Rock Island District and its association with the TRIB VERMILION RIVER make it a key component of the local water resource and climate landscape, emphasizing the need for ongoing oversight and maintenance to ensure its long-term sustainability and safety.
Year Completed |
1975 |
Dam Length |
1285 |
Dam Height |
26 |
River Or Stream |
TRIB VERMILION RIVER |
Primary Dam Type |
Earth |
Nid Storage |
80 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
26 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Vermilion River Near Leonore
|
17cfs |
Fox River At Dayton
|
672cfs |
Illinois River At Marseilles
|
3770cfs |
Illinois River At Henry
|
3410cfs |
East Bureau Creek Near Bureau
|
2cfs |
Big Bureau Creek At Princeton
|
8cfs |
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.
Alleman Lake Dam
Ed Hand Highway 95, Deer Park