De Wees Lake Dam Reservoir Report
Last Updated: December 20, 2025
De Wees Lake Dam, located in Adams County, Illinois, is a private earth dam primarily used for recreation purposes.
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Summary
Built in 1965 by the USDA NRCS, this dam stands at a height of 31 feet and has a length of 285 feet. The dam has a storage capacity of 98 acre-feet and a spillway width of 50 feet, making it a vital structure for managing water resources in the area.
Despite being classified as having a low hazard potential, De Wees Lake Dam is regulated by the Illinois Department of Natural Resources and undergoes regular inspections to ensure its safety and functionality. The dam is situated on the TRIB BEEBE CREEK tributary and is under the jurisdiction of the state, with enforcement and permitting responsibilities falling under the IDNR. The risk assessment for the dam is moderate, indicating the need for ongoing monitoring and management measures to mitigate potential issues.
In the event of an emergency, the dam's Emergency Action Plan (EAP) status and readiness are not currently available. However, with its controlled outlet gates and uncontrolled spillway, De Wees Lake Dam plays a crucial role in water management and recreation in the Kinderhook-Offstream area. Climate and water resource enthusiasts will find this dam to be a fascinating example of infrastructure designed to balance the needs of both human recreation and environmental protection.
Year Completed |
1965 |
Dam Length |
285 |
Dam Height |
31 |
River Or Stream |
TRIB BEEBE CREEK |
Primary Dam Type |
Earth |
Nid Storage |
98 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
31 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Bay Creek At Pittsfield
|
43cfs |
Bear Creek At Hannibal
|
2cfs |
Salt River Near New London
|
82cfs |
Spencer Cr. Bl Plum Cr. Nr Frankford
|
24cfs |
Illinois River At Valley City
|
2970cfs |
North River At Palmyra
|
15cfs |
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.
De Wees Lake Dam