Mill Picayune Watershed Site B-3 Reservoir Report
Last Updated: December 13, 2025
Mill Picayune Watershed Site B-3 is a flood risk reduction structure located in Harrison County, Iowa, along the TR-PICAYUNE CREEK.
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Summary
Built in 1962 by the USDA NRCS, this earth dam stands at a height of 38 feet and has a length of 493 feet, providing storage of 247 acre-feet of water. With a normal storage capacity of 70 acre-feet and a surface area of 8.9 acres, this site plays a crucial role in mitigating flood risks in the area.
Managed by the local government and regulated by the Iowa DNR, this dam has a high hazard potential but is currently assessed as satisfactory in condition. The spillway, with a width of 3 feet, is uncontrolled, and the structure is inspected every two years to ensure its integrity. While the primary purpose of this dam is flood risk reduction, it also serves other purposes such as recreation, highlighting its importance as a multi-functional water resource management system in the region.
Overall, Mill Picayune Watershed Site B-3 is a vital piece of infrastructure in Harrison County, Iowa, contributing to the protection of the local community from flooding events. With its strategic location, effective design, and regular maintenance, this dam exemplifies the intersection of water resource management and climate resilience, showcasing the importance of sustainable infrastructure for safeguarding against natural hazards in the area.
Year Completed |
1962 |
Dam Length |
493 |
Dam Height |
38 |
River Or Stream |
TR-PICAYUNE CREEK |
Primary Dam Type |
Earth |
Surface Area |
8.9 |
Drainage Area |
0.73 |
Nid Storage |
247 |
Hazard Potential |
High |
Foundations |
Soil |
Nid Height |
38 |
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 |
West Nishnabotna River At Hancock
|
154cfs |
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.
Mill Picayune Watershed Site B-3