Anthon Subwatershed M-4001 Reservoir Report
Last Updated: December 13, 2025
Anthon Subwatershed M-4001, located in Anthon, Iowa, is a key water resource managed by the local government for purposes such as fire protection, stock, or small fish pond management, and flood risk reduction.
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Summary
Built in 1954 by the USDA NRCS, this Earth-type dam stands 28 feet tall and spans 400 feet, with a storage capacity of 37 acre-feet and a surface area of 1.3 acres. Situated on the TR-Little Sioux River, this dam plays a vital role in managing water flow and reducing flood risks in the region.
With a low hazard potential and a moderate risk assessment rating, Anthon Subwatershed M-4001 is currently not rated for its condition but is regulated, permitted, inspected, and enforced by the Iowa Department of Natural Resources. Although it has not undergone recent inspections or assessments, the dam continues to serve its primary purposes effectively. The surrounding area, including Woodbury County in Iowa, benefits from the water management and flood control provided by this structure, ensuring the safety and sustainability of the local ecosystem and communities. With its long history and continued relevance in water resource management, Anthon Subwatershed M-4001 remains a critical asset in the region's efforts to address climate-related challenges and ensure water security for all stakeholders.
Year Completed |
1954 |
Dam Length |
400 |
Dam Height |
28 |
River Or Stream |
TR-LITTLE SIOUX RIVER |
Primary Dam Type |
Earth |
Surface Area |
1.3 |
Drainage Area |
0.16 |
Nid Storage |
37 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
28 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Little Sioux River At Correctionville
|
327cfs |
West Fork Ditch At Hornick
|
80cfs |
Maple River At Mapleton
|
323cfs |
Floyd River At James
|
187cfs |
Missouri River At Sioux City
|
15100cfs |
Little Sioux River Near Turin
|
1040cfs |
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.
Anthon Subwatershed M-4001