Arnold-Armstrong Subwtrshd Sta 99+95 Reservoir Report
Last Updated: December 14, 2025
The Arnold-Armstrong Subwatershed Station 99+95 is a vital water resource infrastructure located in Monona, Iowa, specifically in the city of Castana.
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Summary
Managed by the local government, this dam was designed by the USDA NRCS and serves multiple purposes including fire protection, stock maintenance, and flood risk reduction. Completed in 1963, this earth dam stands at a height of 24 feet with a length of 212 feet, providing a storage capacity of 113 acre-feet and covering a surface area of 5.3 acres.
Situated on Dutch Creek, the Arnold-Armstrong Subwatershed Station 99+95 plays a crucial role in managing water resources in the region, with its state-regulated operations overseen by the Iowa DNR. While classified as having a low hazard potential, the dam's condition remains unrated, with moderate risk assessment indicating a level 3 risk. Despite lacking recent inspection and assessment data, the dam continues to fulfill its intended functions effectively, underscoring its importance in safeguarding the local community against potential water-related emergencies.
With its strategic location and design features, the Arnold-Armstrong Subwatershed Station 99+95 stands as a testament to effective water resource management practices. As a key component of the local water infrastructure, this dam not only ensures water availability for various uses but also plays a significant role in mitigating flood risks in the area. As climate change impacts continue to pose challenges to water resources, the responsible management and upkeep of structures like the Arnold-Armstrong Subwatershed Station 99+95 are essential to safeguarding communities and ecosystems in the region.
Year Completed |
1963 |
Dam Length |
212 |
Dam Height |
24 |
River Or Stream |
DUTCH CREEK |
Primary Dam Type |
Earth |
Surface Area |
5.3 |
Drainage Area |
1.45 |
Nid Storage |
113 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
24 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Maple River At Mapleton
|
323cfs |
West Fork Ditch At Hornick
|
80cfs |
Little Sioux River Near Turin
|
1040cfs |
Monona-Harrison Ditch Near Turin
|
158cfs |
Missouri River At Decatur
|
14900cfs |
Little Sioux River At Correctionville
|
327cfs |
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.
Arnold-Armstrong Subwtrshd Sta 99+95