Croy Subwatershed Site M-10500 Reservoir Report
Last Updated: December 14, 2025
Located in Monona County, Iowa, the Croy Subwatershed Site M-10500 is a local government-owned dam designed by the USDA NRCS for various purposes including fire protection, stock, or small fish pond, and flood risk reduction.
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Summary
Completed in 1952, this earth dam stands at a height of 67 feet and has a storage capacity of 139 acre-feet, serving the TR- Maple River. With a drainage area of 0.51 square miles and a surface area of 5 acres, this structure plays a crucial role in managing water resources in the region.
Even though the dam has a low hazard potential and is currently rated as 'Not Rated' in terms of its condition assessment, it is regulated by the Iowa DNR and undergoes state permitting, inspection, and enforcement. The dam's risk assessment is moderate, and there are no specific risk management measures or emergency action plan in place as of the latest data update in May 2021. Despite these challenges, the Croy Subwatershed Site M-10500 continues to be a vital component of the water infrastructure in the area, contributing to both water resource management and climate resilience efforts.
For water resource and climate enthusiasts, the Croy Subwatershed Site M-10500 offers a fascinating glimpse into the intricate network of dams and structures that play a critical role in safeguarding communities and ecosystems from the impacts of extreme weather events and flooding. As part of the larger Rock Island District, this dam stands as a testament to the collaborative efforts between federal, state, and local agencies in ensuring the sustainable management of water resources. Its location in the picturesque surroundings of Little Sioux adds to its significance, highlighting the intersection of nature, engineering, and environmental stewardship in the face of changing climate patterns.
Year Completed |
1952 |
Dam Height |
67 |
River Or Stream |
TR- MAPLE RIVER |
Primary Dam Type |
Earth |
Surface Area |
5 |
Drainage Area |
0.51 |
Nid Storage |
139 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
67 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Maple River At Mapleton
|
323cfs |
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.
Croy Subwatershed Site M-10500