South Magnolia Watershed Site 3 Reservoir Report
Last Updated: December 13, 2025
South Magnolia Watershed Site 3, located in Harrison County, Iowa, is a crucial water resource managed by the local government.
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Summary
Built in 1958 by the USDA SCS, this earth dam serves multiple purposes including fire protection, stock watering, and small fish pond maintenance. With a height of 28 feet and a length of 735 feet, the dam has a storage capacity of 72 acre-feet and covers a surface area of 2.8 acres.
The dam is situated on TR-WILLOW CREEK and is regulated by the Iowa DNR, with state permitting, inspection, and enforcement in place. Despite its low hazard potential and moderate risk assessment rating, the condition of the dam has not been officially assessed. While the last inspection took place in 1965, the dam's emergency action plan status remains unclear, highlighting the need for updated risk management measures and adherence to state guidelines.
South Magnolia Watershed Site 3 plays a vital role in flood risk reduction within the region, providing valuable water resources for both agricultural and environmental purposes. Climate enthusiasts and water resource management professionals are encouraged to monitor and support the ongoing maintenance and regulatory efforts to ensure the long-term sustainability of this important infrastructure.
Year Completed |
1958 |
Dam Length |
735 |
Dam Height |
28 |
River Or Stream |
TR-WILLOW CREEK |
Primary Dam Type |
Earth |
Surface Area |
2.8 |
Drainage Area |
0.46 |
Nid Storage |
72 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
28 |
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 |
Big Papillion Cr
|
38cfs |
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.
South Magnolia Watershed Site 3