Cottonwood-Green Valley Subws Sta 14+10 Reservoir Report
Last Updated: December 13, 2025
Located in Monona, Iowa, the Cottonwood-Green Valley Subws Sta 14+10 is a local government-owned structure designed by the USDA NRCS for fire protection, stock, or small fish pond purposes.
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Summary
Completed in 1966, this earth dam stands at a height of 32 feet and has a length of 568 feet, with a storage capacity of 45 acre-feet. Situated on the TR-MAPLE RIVER, this dam serves to reduce flood risks in the area while also providing essential water resources for various needs.
With a low hazard potential and a moderate risk assessment score of 3, the Cottonwood-Green Valley Subws Sta 14+10 is regulated by the Iowa DNR and undergoes state permitting, inspection, and enforcement. Although its condition is currently not rated, this dam plays a crucial role in maintaining water resources in the region. Despite not having outlet gates or locks, this uncontrolled spillway dam ensures the safety and stability of the surrounding area.
Water resource and climate enthusiasts will find the Cottonwood-Green Valley Subws Sta 14+10 an intriguing structure with its unique design and purpose. As a vital asset for flood risk reduction and water storage, this dam serves as a testament to the collaborative efforts between federal and state agencies in managing and safeguarding water resources in Iowa.
Year Completed |
1966 |
Dam Length |
568 |
Dam Height |
32 |
River Or Stream |
TR-MAPLE RIVER |
Primary Dam Type |
Earth |
Surface Area |
2.2 |
Drainage Area |
0.4 |
Nid Storage |
45 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
32 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Little Sioux River Near Turin
|
1040cfs |
Maple River At Mapleton
|
323cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Soldier River At Pisgah
|
112cfs |
West Fork Ditch At Hornick
|
80cfs |
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.
Cottonwood-Green Valley Subws Sta 14+10