Tiskilwa Structure 5 Dam Reservoir Report
Last Updated: December 14, 2025
Located in Tiskilwa, Illinois, the Tiskilwa Structure 5 Dam, also known as Twin Faun Lake Dam, was completed in 1960 by the USDA NRCS.
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Summary
This earth dam stands at a height of 60 feet and stretches 270 feet in length, serving primarily for flood risk reduction. With a storage capacity of 352 acre-feet and a drainage area of 0.6 square miles, the dam plays a crucial role in managing water flow along the Durfess Run river.
Despite its age, the Tiskilwa Structure 5 Dam remains state regulated and inspected by the Illinois Department of Natural Resources. Classified with a high hazard potential, the dam features an uncontrolled spillway with a width of 104 feet, capable of handling a maximum discharge of 2330 cubic feet per second. The dam's condition assessment is currently listed as "Not Available," emphasizing the importance of ongoing monitoring and maintenance to ensure its continued effectiveness in flood control and recreation activities for the local community.
Year Completed |
1960 |
Dam Length |
270 |
Dam Height |
60 |
River Or Stream |
DURFESS RUN |
Primary Dam Type |
Earth |
Surface Area |
7 |
Drainage Area |
0.6 |
Nid Storage |
352 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
High |
Foundations |
Unlisted/Unknown |
Nid Height |
60 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Big Bureau Creek At Princeton
|
8cfs |
East Bureau Creek Near Bureau
|
2cfs |
Illinois River At Henry
|
3410cfs |
Indian Creek Near Wyoming
|
3cfs |
Vermilion River Near Leonore
|
17cfs |
Rock River At Como
|
3610cfs |
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.
Tiskilwa Structure 5 Dam