Twelve Mile Creek Watershed Site 27 Reservoir Report
Last Updated: December 12, 2025
Twelve Mile Creek Watershed Site 27 is a local government-owned dam located in Westerville, Iowa, within the Union County.
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Summary
Constructed in 1986 by the USDA NRCS, this earth-type dam serves multiple purposes such as fire protection, creating a stock or small fish pond, and reducing flood risks. With a height of 31 feet and a length of 550 feet, the dam has a storage capacity of 293 acre-feet and covers a surface area of 10.3 acres.
Managed by the Iowa DNR, Twelve Mile Creek Watershed Site 27 is regulated, permitted, inspected, and enforced by state authorities. Despite having a low hazard potential, the dam's condition is currently not rated, and there is a moderate risk level associated with its operations. The dam does not have an emergency action plan in place, and there is limited information available on its risk management measures and inundation mapping.
Located in the Rock Island District and falling under the jurisdiction of Representative Cindy Axne, the dam plays a crucial role in water resource management in the area. Its significance lies in providing essential services like fire protection, agriculture, and flood mitigation while also serving as a habitat for fish and wildlife. As an integral part of the local ecosystem, Twelve Mile Creek Watershed Site 27 stands as a testament to sustainable water resource management practices in Iowa.
Year Completed |
1986 |
Dam Length |
550 |
Dam Height |
31 |
River Or Stream |
TR- TWELVE MILE CR. |
Primary Dam Type |
Earth |
Surface Area |
10.3 |
Drainage Area |
0.96 |
Nid Storage |
293 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
31 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Thompson River At Davis City
|
22cfs |
East Fork 102 River At Bedford
|
1cfs |
Raccoon River At Van Meter
|
1640cfs |
South River Near Ackworth
|
18cfs |
North River Near Norwalk
|
48cfs |
Middle River Near Indianola
|
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 27