Otter Lake Dam Reservoir Report
Nearby: Whites Pond Dam Austiff Pond Dam
Last Updated: December 21, 2025
Otter Lake Dam, located in Macoupin, Illinois, serves as a crucial water resource for the surrounding area.
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Summary
Built in 1969, this earth dam stands at a height of 71 feet and spans a length of 1010 feet, providing a storage capacity of 24,708 acre-feet. Its primary purpose is for recreation, with water supply being a secondary benefit. The dam is situated on the West Fork Otter Creek and is regulated by the Illinois Department of Natural Resources.
With a maximum discharge capacity of 21,153 cubic feet per second, Otter Lake Dam plays a key role in managing water levels and ensuring flood control in the region. The dam's spillway, with a width of 167 feet, is uncontrolled, adding an element of natural flow to the water management system. Despite being classified as having a significant hazard potential, its risk assessment is moderate, signifying a level of stability in its operations. Regular inspections are conducted to ensure its structural integrity and safety standards are maintained.
Otter Lake Dam's strategic location and design make it a vital asset for both recreational activities and water supply management in the area. Its presence not only enhances the natural landscape but also contributes to the overall environmental sustainability and climate resilience of the region. As a public utility, the dam serves as a testament to the importance of responsible water resource management in the face of changing climatic conditions.
Year Completed |
1969 |
Dam Length |
1010 |
Dam Height |
71 |
River Or Stream |
WEST FORK OTTER CREEK |
Primary Dam Type |
Earth |
Surface Area |
760 |
Drainage Area |
20.2 |
Nid Storage |
24708 |
Outlet Gates |
Uncontrolled |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
71 |
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.
Otter Lake Dam