Twelve Mile Creek Watershed Site 58 Reservoir Report
Last Updated: December 12, 2025
Twelve Mile Creek Watershed Site 58 in Afton, Iowa, is a locally owned Earth dam completed in 1985 by the USDA NRCS with a primary purpose of fire protection, stock, or small fish pond, and flood risk reduction.
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Summary
This low-hazard potential structure has a height of 28 feet and a length of 650 feet, providing a storage capacity of 128 acre-feet. Located on TR- Twelve Mile Creek in Union County, Iowa, this dam serves as a critical resource for water supply and flood control in the region.
Managed by the Iowa Department of Natural Resources, this dam is regulated, permitted, inspected, and enforced to ensure its safety and functionality. With a drainage area of 0.45 square miles and a normal storage capacity of 41 acre-feet, Twelve Mile Creek Watershed Site 58 plays a vital role in managing water flow and mitigating flood risks in the area. The structure's design and construction by the Natural Resources Conservation Service reflect a commitment to sustainable water resource management and environmental conservation.
Despite being rated as "Not Rated" in terms of condition assessment, Twelve Mile Creek Watershed Site 58 is considered to have a moderate risk level, with appropriate risk management measures in place. As a part of the Rock Island District, this site represents a collaboration between local and federal agencies to ensure the safety and resilience of water infrastructure in the region. For water resource and climate enthusiasts, this site offers a fascinating insight into the intersection of water management, environmental protection, and community resilience in the face of changing climate patterns.
Year Completed |
1985 |
Dam Length |
650 |
Dam Height |
28 |
River Or Stream |
TR- TWELVE MILE CR. |
Primary Dam Type |
Earth |
Surface Area |
8 |
Drainage Area |
0.45 |
Nid Storage |
128 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
28 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Thompson River At Davis City
|
22cfs |
Raccoon River At Van Meter
|
1640cfs |
East Fork 102 River At Bedford
|
1cfs |
South Raccoon River At Redfield
|
268cfs |
Raccoon River Near West Des Moines
|
1300cfs |
North River Near Norwalk
|
48cfs |
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.
Twelve Mile Creek Watershed Site 58
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