Mill Picayune Watershed Site G-1 Reservoir Report
Last Updated: December 13, 2025
Mill Picayune Watershed Site G-1, located in Harrison, Iowa, is a local government-owned earth dam completed in 1986 by the USDA NRCS, with a primary purpose of fire protection, stock, or small fish pond usage.
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Summary
This dam stands at 34 feet in height and spans 640 feet in length, with a storage capacity of 150 acre-feet and a surface area of 8.4 acres. It serves the community of Woodbine and is regulated by the Iowa DNR, with state permitting, inspection, and enforcement in place to ensure its safety and functionality.
With a low hazard potential and a moderate risk assessment rating of 3, Mill Picayune Watershed Site G-1 is deemed to be in fair condition, though not rated specifically. Despite lacking an official condition assessment and emergency action plan, this dam plays a crucial role in flood risk reduction and water resource management within the TR-Mill Cr. stream. Its location in a picturesque setting underscores the importance of proper maintenance and oversight to safeguard against potential risks and ensure its long-term effectiveness as a vital part of the local water infrastructure. For water resource and climate enthusiasts, this site offers a unique opportunity to observe the intersection of human engineering and natural landscapes in sustainable water management practices.
Year Completed |
1986 |
Dam Length |
640 |
Dam Height |
34 |
River Or Stream |
TR-MILL CR. |
Primary Dam Type |
Earth |
Surface Area |
8.4 |
Drainage Area |
0.41 |
Nid Storage |
150 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
34 |
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 G-1