Twelve Mile Creek Watershed Site 73 Reservoir Report
Last Updated: February 6, 2026
Twelve Mile Creek Watershed Site 73, located in Union County, Iowa, is a vital water resource managed by the local government for fire protection, stock, and small fish pond purposes.
Summary
Constructed in 1979 by the USDA NRCS, this earth dam stands at a height of 30 feet and has a normal storage capacity of 32 acre-feet. With a surface area of 5.1 acres and a drainage area of 0.34 square miles, this dam plays a crucial role in flood risk reduction for the surrounding area.
Managed by the Iowa Department of Natural Resources, this dam on Twelve Mile Creek is designated as a state-regulated and permitted structure. While it has a low hazard potential and moderate risk assessment rating, it has not been rated for condition assessment. With its uncontrolled spillway and lack of outlet gates, this dam serves as a valuable asset for water resource management in the region. The site is located in Afton, with a latitude of 41.1055 and longitude of -94.3262, making it a key location for water enthusiasts and climate researchers interested in the conservation and regulation of water resources.
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Wind
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Humidity
15-Day Weather Outlook
Year Completed |
1979 |
Dam Length |
420 |
Dam Height |
30 |
River Or Stream |
TR-TWELVE MILE CREEK |
Primary Dam Type |
Earth |
Surface Area |
5.1 |
Drainage Area |
0.34 |
Nid Storage |
92 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
30 |
Seasonal Comparison
5-Day Hourly Forecast Detail
Nearby Streamflow Levels
South Raccoon River At Redfield
|
268cfs |
Raccoon River At Van Meter
|
1640cfs |
East Fork 102 River At Bedford
|
1cfs |
Middle Raccoon River At Panora
|
92cfs |
Raccoon River Near West Des Moines
|
1300cfs |
Thompson River At Davis City
|
22cfs |
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 73