Big Coon Subwatershed Site 3a-4 Reservoir Report
Last Updated: December 14, 2025
Big Coon Subwatershed Site 3a-4, located in Anthon, Iowa, is a significant earth dam constructed in 1999 by the USDA NRCS to serve multiple purposes such as fire protection, stock, small fish pond, and flood risk reduction.
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Summary
This dam has a height of 36 feet and a length of 457 feet, with a storage capacity of 78 acre-feet and a surface area of 3.5 acres. It is regulated and inspected by the Iowa DNR, ensuring its safety and compliance with state regulations.
The dam's primary purpose is to provide essential water resources for the surrounding area while also offering flood risk reduction measures. Despite its low hazard potential and moderate risk assessment, the dam's condition remains unrated, highlighting the need for ongoing monitoring and maintenance. The presence of uncontrolled spillways indicates a careful balance between storage capacity and controlled water release to prevent potential flooding events.
With its location on TR- BIG CREEK and proximity to Woodbury County, Big Coon Subwatershed Site 3a-4 serves as a vital water management structure designed to enhance the local ecosystem and protect against potential water-related hazards. Its construction by the USDA NRCS underscores a commitment to sustainable resource management and climate resilience in the region. As a focal point for water resource and climate enthusiasts, this site offers a fascinating glimpse into the intersection of engineering, environmental conservation, and community safety.
Year Completed |
1999 |
Dam Length |
457 |
Dam Height |
36 |
River Or Stream |
TR- BIG CREEK |
Primary Dam Type |
Earth |
Surface Area |
3.5 |
Drainage Area |
0.32 |
Nid Storage |
78 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
36 |
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 3a-4