Iowa Falls Milldam Reservoir Report
Nearby: Moorewood Farms Dam John Hackbarth
Last Updated: December 13, 2025
The Iowa Falls Milldam is a historic structure located on the Iowa River in Hardin County, Iowa.
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Summary
Built in 1925, this gravity dam serves multiple purposes, including hydroelectric power generation, recreation, and water supply. With a height of 26 feet and a length of 225 feet, the dam has a storage capacity of 4751 acre-feet and covers a surface area of 365 acres.
Managed by the Iowa Department of Natural Resources, the Iowa Falls Milldam is considered to have a low hazard potential and is in satisfactory condition as of the last assessment in 2016. While the dam has not been modified in recent years, it is subject to regular inspections, permitting, and enforcement by state regulatory agencies to ensure its safety and functionality. The dam's location in the Rock Island District and its designation as a public utility highlight its significance in providing renewable energy and recreational opportunities in the region.
Despite its moderate risk assessment, the Iowa Falls Milldam continues to play a vital role in water resource management and climate resilience efforts in Iowa Falls. With its historic significance, multiple uses, and state-regulated operations, the dam serves as a valuable asset for the community while also contributing to sustainable water supply and energy generation practices in the area. Enthusiasts of water resources and climate change will find the Iowa Falls Milldam an intriguing example of how infrastructure can adapt to evolving environmental challenges while fulfilling essential societal needs.
Year Completed |
1925 |
Dam Length |
225 |
Dam Height |
26 |
River Or Stream |
IOWA RIVER |
Primary Dam Type |
Gravity |
Surface Area |
365 |
Drainage Area |
679 |
Nid Storage |
4751 |
Hazard Potential |
Low |
Foundations |
Rock, Soil |
Nid Height |
26 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
South Fork Iowa River Ne Of New Providence
|
79cfs |
Iowa River Near Rowan
|
195cfs |
Boone River Near Webster City
|
232cfs |
Beaver Creek At New Hartford
|
123cfs |
Iowa River At Marshalltown
|
1040cfs |
South Skunk River Near Ames
|
92cfs |
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.
Iowa Falls Milldam