Mike Mikkelson Subwatershed M-5905 Reservoir Report
Last Updated: December 14, 2025
The Mike Mikkelson Subwatershed M-5905 is a locally owned earth dam located in Monona, Iowa, designed by the USDA NRCS for fire protection, stock, or small fish pond purposes.
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Summary
Completed in 1960, this dam has a height of 24 feet and a storage capacity of 89 acre-feet. Situated along the TR-Cottonwood Creek, it covers a surface area of 6 acres and serves a drainage area of 1.81 square miles.
Managed by the Iowa DNR, this dam has a low hazard potential and a moderate risk assessment rating. While it is not currently rated for condition assessment, it is regulated, permitted, inspected, and enforced by state agencies. Although it does not have outlet gates or locks, it features an uncontrolled spillway. With a history of no modifications and no associated structures, the Mike Mikkelson Subwatershed M-5905 remains an essential asset for flood risk reduction and water resource management in the Little Sioux area.
Enthusiasts of water resources and climate in Iowa will find the Mike Mikkelson Subwatershed M-5905 a fascinating example of a local government-owned dam designed to serve multiple purposes. With its strategic location, design features, and risk management measures, this dam plays a crucial role in enhancing water security and resilience in the region. Its history, current status, and regulatory framework provide valuable insights for those interested in sustainable water infrastructure and environmental stewardship.
Year Completed |
1960 |
Dam Height |
24 |
River Or Stream |
TR- COTTONWOOD CREEK |
Primary Dam Type |
Earth |
Surface Area |
6 |
Drainage Area |
1.81 |
Nid Storage |
89 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
24 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Soldier River At Pisgah
|
112cfs |
Maple River At Mapleton
|
323cfs |
Missouri River At Decatur
|
14900cfs |
West Fork Ditch At Hornick
|
80cfs |
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.
Mike Mikkelson Subwatershed M-5905