Otter Lake Low Flow Dam Reservoir Report
Nearby: Austiff Pond Dam Hartsook Pond Dam 1
Last Updated: December 21, 2025
The Otter Lake Low Flow Dam is a vital structure located in Hagaman, Illinois, along Otter Creek.
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Summary
Built in 2008 by HURST-ROSCHE ENGINEERS, INC., this rockfill dam stands at a height of 6.3 feet and serves the primary purpose of debris control. With a storage capacity of 217 acre-feet and a drainage area of 10.8 square miles, the dam plays a crucial role in managing water flow and protecting the surrounding environment.
Despite its low hazard potential, the dam is regulated by the Illinois Department of Natural Resources and undergoes regular inspections to ensure its structural integrity. With a maximum discharge capacity of 2087 cubic feet per second and an uncontrolled spillway width of 317 feet, the dam is equipped to handle extreme weather events and prevent flooding downstream. Its moderate risk assessment highlights the importance of ongoing risk management measures to safeguard the community and the environment.
As a key component of the local water management system, the Otter Lake Low Flow Dam not only provides essential debris control but also contributes to the overall resilience of the region against the impacts of climate change. With a focus on sustainable water resource management, this dam serves as a model for effective infrastructure planning and maintenance in the face of evolving environmental challenges.
Year Completed |
2008 |
Dam Length |
317 |
Dam Height |
6.3 |
River Or Stream |
OTTER CREEK |
Primary Dam Type |
Rockfill |
Surface Area |
42 |
Drainage Area |
10.8 |
Nid Storage |
217 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
6 |
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 Low Flow Dam