Alden Milldam Reservoir Report
Nearby: Iowa Falls Milldam Hoffman Dam
Last Updated: December 13, 2025
Alden Milldam, located in Alden, Iowa, is a gravity-type dam constructed in 1932 on the Iowa River for recreational purposes.
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Summary
The dam stands at 11 feet tall and spans 375 feet in length, with a storage capacity of 762 acre-feet. Although the primary purpose of the dam is for recreation, it also serves as a state-regulated structure under the jurisdiction of the Iowa Department of Natural Resources.
The dam has a low hazard potential and is currently rated as "Not Rated" in terms of its condition assessment. The last inspection was conducted in 1989, with no updated assessment available. Despite its moderate risk level, the dam has not been assigned a Dam Safety Action Classification (DSAC) date, and no specific risk management measures have been identified. It is important for water resource and climate enthusiasts to monitor the maintenance and safety of Alden Milldam to ensure its continued functionality and public safety in the face of potential climate challenges.
Year Completed |
1932 |
Dam Length |
375 |
Dam Height |
11 |
River Or Stream |
IOWA RIVER |
Primary Dam Type |
Gravity |
Surface Area |
140 |
Drainage Area |
638 |
Nid Storage |
762 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
11 |
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 |
South Skunk River Near Ames
|
92cfs |
Des Moines River Near Stratford
|
1720cfs |
Squaw Creek At Ames
|
53cfs |
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.
Alden Milldam