Little Cache Structure 5 Dam Reservoir Report

Last Updated: December 5, 2025

Little Cache Structure 5 Dam, located in Johnson County, Illinois, was completed in 1973 by the USDA NRCS and serves as a crucial flood risk reduction measure along the TRIB LITTLE CACHE CREEK.


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Summary

This private-owned earth dam stands at a height of 31 feet and spans 400 feet in length, with a storage capacity of 578 acre-feet. Despite its low hazard potential, the dam is regulated by the Illinois Department of Natural Resources and undergoes regular state inspections and enforcement to ensure its structural integrity.

The dam features an uncontrolled spillway with a width of 75 feet and operates with uncontrolled outlet gates. Its primary purpose and design are focused on flood risk reduction, effectively mitigating the impact of high water levels in the region. Despite its moderate risk assessment rating, the dam currently lacks a comprehensive emergency action plan and condition assessment, highlighting areas for potential improvement in its risk management measures. With its strategic location and design, Little Cache Structure 5 Dam stands as a vital infrastructure supporting water resource management and climate resilience efforts in the area.

Year Completed

1973

Dam Length

400

Dam Height

31

River Or Stream

TRIB LITTLE CACHE CREEK

Primary Dam Type

Earth

Nid Storage

578

Outlet Gates

Uncontrolled

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

31
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.