Winner Dam Reservoir Report
Nearby: Harper Century Farm Dam Kasparbauer
Last Updated: December 13, 2025
Winner Dam, located in Missouri Valley, Iowa, is a privately-owned structure designed by the USDA NRCS and regulated by the Iowa DNR.
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Summary
Completed in 2011, this earth dam stands 41 feet tall and stretches 800 feet in length, serving primarily for flood risk reduction. With a storage capacity of 190 acre-feet and a surface area of 8 acres, Winner Dam plays a crucial role in managing water resources for the surrounding area.
The dam also serves multiple purposes including fish and wildlife pond creation, grade stabilization, and recreation. With a low hazard potential and not yet rated for condition assessment, Winner Dam remains a reliable asset for the community. Despite not having any associated structures or outlet gates, the dam's construction and operation are overseen by the Natural Resources Conservation Service, ensuring its effectiveness in protecting against floods and contributing to the local ecosystem.
With its strategic location along a tributary to Thompson Creek, Winner Dam plays a vital role in water management for Harrison County, Iowa. As a key element in flood risk reduction efforts, this structure demonstrates the importance of sustainable water resource management and the collaboration between private owners, regulatory agencies, and design experts in safeguarding the local environment and community from potential water-related hazards.
Year Completed |
2011 |
Dam Length |
800 |
Dam Height |
41 |
River Or Stream |
Trib to Thompson Creek |
Primary Dam Type |
Earth |
Surface Area |
8 |
Drainage Area |
0.78 |
Nid Storage |
190 |
Outlet Gates |
None |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
41 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Boyer River At Logan
|
417cfs |
Soldier River At Pisgah
|
112cfs |
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Maple River At Mapleton
|
323cfs |
Missouri River At Decatur
|
15500cfs |
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.
Winner Dam