Behnken Lake Dam Reservoir Report
Last Updated: December 22, 2025
Behnken Lake Dam, located in Randolph, Illinois, was completed in 1975 and serves primarily for recreational purposes.
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Summary
The dam stands at a height of 24 feet and has a length of 700 feet, providing storage capacity of 85 acre-feet with a normal storage level of 62 acre-feet. Situated on TRIB MARYS RIVER, the dam is owned privately but regulated by the Illinois Department of Natural Resources (IDNR) with state jurisdiction, permitting, inspection, and enforcement in place.
With a low hazard potential and a moderate risk assessment rating, Behnken Lake Dam has an uncontrolled spillway and is constructed mainly of earth and stone materials on a soil foundation. The dam's condition assessment is currently not available, and the last inspection was conducted in August 2018 with a scheduled frequency of every 5 years. While the dam does not have outlet gates, locks, or associated structures, it remains an essential component for recreational activities in STEELEVILLE, Illinois, attracting water resource and climate enthusiasts to its tranquil waters and scenic surroundings.
Despite its simple design and low hazard potential, Behnken Lake Dam plays a vital role in providing recreational opportunities and water storage in the region. As a privately owned structure regulated by the IDNR, the dam ensures public safety and environmental protection while offering a serene location for outdoor activities. With its longstanding history and ongoing maintenance, Behnken Lake Dam continues to be a significant feature along TRIB MARYS RIVER, contributing to the natural beauty and water resource management of Randolph, Illinois.
Year Completed |
1975 |
Dam Length |
700 |
Dam Height |
24 |
River Or Stream |
TRIB MARYS RIVER |
Primary Dam Type |
Earth |
Surface Area |
8 |
Drainage Area |
0.06 |
Nid Storage |
85 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
24 |
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.
Behnken Lake Dam