Little Rocky Run Lake Dam Reservoir Report
Last Updated: December 14, 2025
Little Rocky Run Lake Dam, located in Hancock County, Illinois, was completed in 1971 by the Corps of Engineers and serves as a vital structure for flood risk reduction along the Little Rocky Run Creek.
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Summary
The dam stands at a height of 64 feet and has a length of 586 feet, providing a storage capacity of 5200 acre-feet. With a spillway width of 465 feet and uncontrolled outlet gates, the dam plays a crucial role in managing water flow during peak discharge events.
The dam is state-regulated by the Illinois Department of Natural Resources, with regular inspections conducted every three years to ensure its structural integrity and safety. Classified as having a significant hazard potential, the dam is designed as an earth dam with a buttress core type, reflecting its robust construction to withstand flood events. Despite its moderate risk assessment, the dam has no available condition assessment data, highlighting the need for continued monitoring and maintenance to ensure its long-term functionality and resilience in the face of changing climate conditions.
For water resource and climate enthusiasts, Little Rocky Run Lake Dam presents a fascinating case study of a locally owned flood control structure that plays a critical role in safeguarding communities against the impacts of extreme weather events. With its strategic location in Tioga, Illinois, and proximity to the Rock Island District of the US Army Corps of Engineers, the dam serves as a key asset in water resource management and climate adaptation efforts in the region. As the dam continues to be monitored and regulated by state authorities, its importance in mitigating flood risks and protecting downstream areas underscores the interconnected relationship between water infrastructure and climate resilience.
Year Completed |
1971 |
Dam Length |
586 |
Dam Height |
64 |
River Or Stream |
LITTLE ROCKY RUN CREEK |
Primary Dam Type |
Earth |
Nid Storage |
5200 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
64 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Bear Creek Near Marcelline
|
5cfs |
Wyaconda River Above Canton
|
13cfs |
Fox River At Wayland
|
8cfs |
Des Moines River At St. Francisville
|
1620cfs |
South Fabius River Near Taylor
|
12cfs |
La Moine River At Colmar
|
18cfs |
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.
Area Campgrounds
| Location | Reservations | Toilets |
|---|---|---|
Warsaw City Campground
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Hubinger Landing Park
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Victory Park
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Canton City River Park
|
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Mississippi Riverfront RV Park
|
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Bear Creek - Mississippi River
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Little Rocky Run Lake Dam