Arnold-Armstrong Subwtrshd Sta 2+05 #3 Reservoir Report

Last Updated: December 14, 2025

Arnold-Armstrong Subwtrshd Sta 2+05 #3 is a dam located in Monona County, Iowa, owned and regulated by the local government.


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Summary

Built in 1962 by the USDA NRCS, this earth dam serves multiple purposes including fire protection, stock watering, and flood risk reduction. With a dam height of 45 feet and a storage capacity of 107 acre-feet, the structure covers a surface area of 5.3 acres and drains an area of 0.8 square miles.

The dam is classified as having a low hazard potential and a moderate risk level, with a spillway type marked as uncontrolled. Despite not being currently rated for condition assessment, the dam is under state regulation and inspection by the Iowa DNR. Located offstream, Arnold-Armstrong Subwtrshd Sta 2+05 #3 plays a crucial role in water resource management in the region, providing essential services and protection to the surrounding community in Castana.

Overall, Arnold-Armstrong Subwtrshd Sta 2+05 #3 stands as a vital infrastructure for water resource and climate enthusiasts, showcasing the importance of sustainable water management practices in mitigating flood risks and supporting local agricultural activities. With its historical significance and functional design, this dam serves as a key component in maintaining the environmental and economic stability of Monona County, Iowa.

Year Completed

1962

Dam Length

363

Dam Height

45

River Or Stream

OFFSTREAM

Primary Dam Type

Earth

Surface Area

5.3

Drainage Area

0.8

Nid Storage

107

Hazard Potential

Low

Foundations

Soil

Nid Height

45
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.