Charles City Milldam Reservoir Report

Last Updated: December 13, 2025

Charles City Milldam, located in Floyd County, Iowa, along the Cedar River, is a gravity dam primarily used for recreation.


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Summary

Built in 1945, this dam stands at a height of 10 feet and spans 236 feet in length, with a maximum storage capacity of 606 acre-feet and a surface area of 120 acres. Despite its low hazard potential and moderate risk assessment rating, the dam's condition remains unrated as of the last inspection in 1999.

Managed by the local government and regulated by the Iowa Department of Natural Resources, Charles City Milldam serves as a popular spot for outdoor enthusiasts seeking recreational activities. Although the dam lacks designated outlet gates and spillways, its uncontrolled spillway type poses minimal risk to surrounding areas. With a drainage area of 1054 square miles, this dam plays a crucial role in water resource management and environmental conservation efforts within the region.

For water resource and climate enthusiasts, Charles City Milldam offers a unique opportunity to explore the intersection of human infrastructure and natural ecosystems. As a focal point for outdoor recreation, this dam showcases the balance between human enjoyment and environmental stewardship in sustainable water management practices. Despite its age, the dam continues to serve as a valuable resource for the community, highlighting the importance of ongoing inspection and maintenance to ensure its safety and longevity in the face of changing climate conditions.

Year Completed

1945

Dam Length

236

Dam Height

10

River Or Stream

CEDAR RIVER

Primary Dam Type

Gravity

Surface Area

120

Drainage Area

1054

Nid Storage

606

Hazard Potential

Low

Foundations

Soil

Nid Height

10
       
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.