Twelve Mile Creek Watershed Site 30 Reservoir Report
Nearby: Swine Graphics Dam #2 Van Hall Dam
Last Updated: December 14, 2025
Twelve Mile Creek Watershed Site 30, located in Union County, Iowa, is a local government-owned earth dam completed in 1986 by the USDA Natural Resources Conservation Service.
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Summary
The dam serves multiple purposes, including fire protection, stock, and small fish pond management, as well as flood risk reduction. With a dam height of 35 feet and a length of 490 feet, the site has a storage capacity of 175 acre-feet and covers a surface area of 6.4 acres.
Managed by the Iowa Department of Natural Resources, Twelve Mile Creek Watershed Site 30 is regulated, permitted, inspected, and enforced by state agencies to ensure its safety and functionality. The dam has a low hazard potential and a moderate risk assessment rating, indicating a relatively low level of risk associated with its operation. Despite not being rated for its condition, the dam is regularly monitored and maintained to meet safety standards.
Situated along the TR- SAND CR. stream, this site plays a crucial role in water resource management and protection in the region. With its strategic location and design, Twelve Mile Creek Watershed Site 30 serves as a vital component of the local ecosystem, providing essential services for both human and environmental well-being.
Year Completed |
1986 |
Dam Length |
490 |
Dam Height |
35 |
River Or Stream |
TR- SAND CR. |
Primary Dam Type |
Earth |
Surface Area |
6.4 |
Drainage Area |
0.58 |
Nid Storage |
175 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
35 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Thompson River At Davis City
|
22cfs |
South River Near Ackworth
|
18cfs |
Chariton River Near Chariton
|
2cfs |
Middle River Near Indianola
|
48cfs |
North River Near Norwalk
|
48cfs |
Raccoon River At Van Meter
|
1640cfs |
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 30