Big Coon Subwatershed Site M-5 Reservoir Report
Last Updated: December 15, 2025
Big Coon Subwatershed Site M-5 is a local government-owned flood risk reduction structure located in Anthon, Iowa, along Coon Creek.
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Summary
Designed by USDA NRCS, this Earth dam stands at 20 feet tall and stretches 565 feet in length, with a storage capacity of 52 acre-feet. Completed in 2000, the dam serves multiple purposes including fire protection, stock or small fish pond, and flood risk reduction for the surrounding area, covering a drainage area of 3.57 square miles.
With a low hazard potential and a moderate risk assessment rating, Big Coon Subwatershed Site M-5 is regulated by the Iowa Department of Natural Resources. The dam is inspected, permitted, and enforced by state agencies, ensuring its structural integrity and safety measures are up to standard. Although the condition assessment is currently marked as "Not Rated," the site's risk management measures are in place to address any potential issues that may arise.
Despite being uncontrolled, the spillway type of this dam is designed to handle any excess water during heavy rainfall events, with a surface area of 1.2 acres. Located within the Rock Island District, this structure plays a critical role in managing water resources in the region and highlights the collaborative efforts between local and federal agencies in safeguarding communities from flood risks and ensuring sustainable water management practices.
Year Completed |
2000 |
Dam Length |
565 |
Dam Height |
20 |
River Or Stream |
COON CREEK |
Primary Dam Type |
Earth |
Surface Area |
1.2 |
Drainage Area |
3.57 |
Nid Storage |
52 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
20 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Little Sioux River At Correctionville
|
327cfs |
Maple River At Mapleton
|
323cfs |
West Fork Ditch At Hornick
|
80cfs |
Floyd River At James
|
187cfs |
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
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.
Big Coon Subwatershed Site M-5